[go: up one dir, main page]

WO2025149476A1 - Tunable cct maximum output laser-phosphor engine with two laser banks - Google Patents

Tunable cct maximum output laser-phosphor engine with two laser banks

Info

Publication number
WO2025149476A1
WO2025149476A1 PCT/EP2025/050235 EP2025050235W WO2025149476A1 WO 2025149476 A1 WO2025149476 A1 WO 2025149476A1 EP 2025050235 W EP2025050235 W EP 2025050235W WO 2025149476 A1 WO2025149476 A1 WO 2025149476A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
beam splitter
luminescent material
received
arrangement
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2025/050235
Other languages
French (fr)
Inventor
Christoph Gerard August HOELEN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Signify Holding BV
Original Assignee
Signify Holding BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Signify Holding BV filed Critical Signify Holding BV
Publication of WO2025149476A1 publication Critical patent/WO2025149476A1/en
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
    • F21K9/64—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V13/00—Producing particular characteristics or distribution of the light emitted by means of a combination of elements specified in two or more of main groups F21V1/00 - F21V11/00
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
    • F21V9/14—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters for producing polarised light
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
    • F21V9/30—Elements containing photoluminescent material distinct from or spaced from the light source
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2033—LED or laser light sources
    • G03B21/204—LED or laser light sources using secondary light emission, e.g. luminescence or fluorescence
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2073—Polarisers in the lamp house
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B33/00—Colour photography, other than mere exposure or projection of a colour film
    • G03B33/10—Simultaneous recording or projection
    • G03B33/12—Simultaneous recording or projection using beam-splitting or beam-combining systems, e.g. dichroic mirrors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
    • F21V9/20—Dichroic filters, i.e. devices operating on the principle of wave interference to pass specific ranges of wavelengths while cancelling others
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3083—Birefringent or phase retarding elements

Definitions

  • the invention relates to a light generating system.
  • the invention further relates to a lighting device comprising the light generating system.
  • US2020/333699A1 discloses a light source apparatus that includes a first light source configured to emit light in a blue wavelength band, a second light source configured to emit light in a red wavelength band, a light amount ratio changer configured to change a light amount ratio between a first polarized light component and a second polarized light component in light of the blue wavelength band, a polarization beam splitter configured to split the first polarized light component and the second polarized light component, a wavelength converter configured to convert the light of the blue wavelength band obtained from the first polarized light component, into light in a red/green wavelength band, and a light combiner configured to combine the light.
  • US2022/091493A1 discloses a light source device that includes blue, green, and red laser light sources.
  • a first retardation plate controls the polarization of blue laser light emitted from the blue laser light source and a polarizing beam splitter that separates the blue laser light whose polarization is controlled by the first retardation plate into a first blue laser light and a second blue laser light.
  • a second retardation plate controls polarization of the second blue laser light separated by the polarizing beam splitter.
  • a fluorescent plate is excited by the first blue laser light emits fluorescent light including a green component and a red component.
  • a first dichroic mirror combines the second blue laser light and light emitted from the green and red laser light sources, to generate combined laser light.
  • a dynamic diffuser plate diffuses the combined laser light to generate diffused laser light.
  • a second dichroic mirror combines the diffused laser light and the fluorescent light.
  • the optics may comprise a first polarizing beam splitter.
  • the first polarizing beam splitter may be configured downstream of the first light generating device and the second light generating device. Additionally, in embodiments, the first polarizing beam splitter may be configured upstream of both the luminescent material arrangement and the diffuser arrangement.
  • the light generating system may, in embodiments, be configured such that the first device light and the second device light received by the first polarizing beam splitter may comprise polarized light.
  • the first polarizing beam splitter may be configured to transmit or reflect light (received by the first polarizing beam splitter) in dependence of its polarization.
  • the first light generating device and the second light generating device may be substantially different.
  • the second light generating device may herein also comprise a plurality of second (solid state) light sources.
  • the second light generating device may comprise a second laser bank comprising a plurality of second lasers.
  • the second light generating device may especially be configured to generate second device light having a second peak wavelength (Xp2).
  • the second device light may have a second peak wavelength (Xp2) selected from the wavelength range of 430-490 nm, such as from the range of 440-480 nm, like from the range of 445-475 nm.
  • the second device light may be blue light.
  • the first polarizing beam splitter may be configured such that a ratio of the amount of p-polarized light being reflected relative to the amount of s-polarized light being reflected may be ⁇ 0.9, such as ⁇ 0.8, like ⁇ 0.6, especially ⁇ 0.4. Yet alternatively, in embodiments, the first polarizing beam splitter may be configured to partially transmit and partially reflect one or more of light comprising the first linear polarization and light comprising the second linear polarization, see also further below. Amounts of light may be based on the spectral power (of the light) (e.g. Watts).
  • the first polarizing beam splitter in a first operational mode of the light generating system may be configured to direct at most 50%, such as at most 40%, like at most 30%, especially at most 20%, more especially at most 10%, including 0% of the first device light to the diffuser arrangement.
  • the first polarizing beam splitter in a first operational mode of the light generating system may be configured to direct at least 50%, such as at least 60%, like at least 70%, especially at least 80%, more especially at least 90%, including 100% of the first device light to the diffuser arrangement.
  • the first polarizing beam splitter may thus, in embodiments, be configured to (re-)direct the (first) device light received by the first polarizing beam splitter in dependence of its polarization.
  • At least part of the first device light received by the first polarizing beam splitter may be directed towards the luminescent material arrangement and/or at least (another) part of the first device light received by the first polarizing beam splitter may be directed towards the diffuser arrangement.
  • the optics together with the second light generating device may be configured such that at least 70%, such as at least 80%, like at least 90%, especially at least 95%, more especially at least 98%, including 100% of the second device light received by the first polarizing beam splitter may be directed towards the luminescent material arrangement.
  • the optics and the second light generating device may be configured such that most of the second device light, especially essentially all of the second device light propagating from the first polarizing beam splitter, may be directed to the luminescent material arrangement (by the first polarizing beam splitter).
  • one or more luminescent materials may be configured to convert incident light into one or more of green and yellow luminescent material light, and one or more other luminescent materials may be configured to convert incident light into one or more of orange and red luminescent material light.
  • the term “luminescent material” especially refers to a material that can convert first radiati on, (especially one or more of UV radiation and blue radiation,) into second radiation.
  • first radiation and second radiation have different spectral power distributions.
  • the terms “luminescent converter” or “converter” may be applied.
  • the term “luminescent material” also the term “phosphor” may be applied.
  • the second radiation has a spectral power distribution at larger wavelengths than the first radiation, which is the case in the so-called downconversion. In specific embodiments, however the second radiation has a spectral power distribution with intensity at smaller wavelengths than the first radiation, which is the case in the so-called up-conversion.
  • the term “luminescence” may refer to phosphorescence. In embodiments, the term “luminescence” may also refer to fluorescence. Instead of the term “luminescence”, also the term “emission” may be applied. Hence, the terms “first radiation” and “second radiation” may refer to excitation radiation and emission (radiation), respectively. Likewise, the term “luminescent material” may in embodiments refer to phosphorescence and/or fluorescence.
  • the term “luminescent material” may also refer to a plurality of different luminescent materials. Hence, the term “luminescent material” may in specific embodiments also refer to a luminescent material composition. The term “luminescent material” herein may also refer to a material comprising a luminescent material, such as a light transmissive host comprising the luminescent material. Examples of possible luminescent materials are indicated further below.
  • the diffuser may be configured to diffuse at least 50%, such as at least 60%, like at least 70%, especially at least 80%, more especially at least 90%, including 100% of the first device light received by the diffuser (arrangement) into diffused device light.
  • the diffuser may especially comprise a substantially polarization maintaining diffuser, i.e., the diffuser may be configured to substantially maintain the polarization of the incident light upon diffusion (and in some embodiments reflection).
  • the diffuser may comprise a metal coated surface textured glass substrate mounted on a heat conductive material such as e.g. a metal or a ceramic.
  • the heat conductive material may be configured to conduct away heat that may be generated in the diffuser due to some absorption of incident device light.
  • the luminescent material light may propagate via a dichroic beam splitter (comprised by the optics, see also further below) to the light exit.
  • the optics may be configured such that the diffused device light may propagate via part of the optics to the light exit.
  • the diffused device light may propagate via one or more reflectors (comprised by the optics) to the light exit.
  • the diffused device light may propagate via a second polarizing beam splitter (comprised by the optics, see also further below) to the light exit.
  • the diffused device light may propagate via a dichroic beam splitter (comprised by the optics, see also further below) to the light exit.
  • the light exit may refer to a position where system light escapes from the light generating system.
  • This may, in embodiments, be a light transmissive window or an opening (in the system).
  • the light transmissive window may in embodiments be provided by an optical component.
  • the amount of first device light comprising the first linear polarization and first device light comprising the second linear polarization may be controlled by the control system, which may in turn be controlling the light generating devices.
  • the control system may especially be configured to control the spectral power distribution of the system light by controlling both the polarization control system and the light generating devices.
  • the optics may further comprise a (polarizing) beam splitter arrangement, configured between the first polarizing beam splitter and the diffuser arrangement, wherein the beam splitter arrangement may be configured (i) to transmit device light received by the beam splitter arrangement and comprising the first linear polarization and to reflect device light received by the beam splitter arrangement and comprising the second linear polarization, or (ii) to reflect device light received by the beam splitter arrangement and comprising the first linear polarization and to transmit device light received by the beam splitter arrangement and comprising the second linear polarization.
  • a (polarizing) beam splitter arrangement configured between the first polarizing beam splitter and the diffuser arrangement, wherein the beam splitter arrangement may be configured (i) to transmit device light received by the beam splitter arrangement and comprising the first linear polarization and to reflect device light received by the beam splitter arrangement and comprising the second linear polarization, or (ii) to reflect device light received by the beam splitter arrangement and comprising the first linear polarization and to transmit device light received by the beam splitter
  • the birefringent rotator may be configured to receive the first device light emitted by the first light generating device and may be configured to adjust (or control) the polarization of the first device light, such that first device light having a predetermined (linear) polarization may be provided to the first polarizing beam splitter.
  • the polarization control system may be configured to control rotation of the birefringent rotator, such that the polarization of the first device light reaching the first polarizing beam splitter may be adjusted.
  • the birefringent rotator may therefore, in embodiments, comprise a X/2 waveplate.
  • the actuator may (also) be configured to control the birefringent rotator.
  • the polarization control system may comprise a separate actuator for the birefringent rotator.
  • the polarization control system may comprise one or more of (A) a birefringent rotator configured downstream of the first light generating device and upstream of the first polarizing beam splitter, wherein the polarization control system may be configured to control rotation of the birefringent rotator (such that the polarization of the first device light reaching the first polarizing beam splitter may be adjusted); and wherein the birefringent rotator may comprise a X/2 waveplate; and (B) an actuator configured to (mechanically) rotate the first light generating device (and optionally the second light generating device), wherein the polarization control system may be configured to control the actuator (such that the polarization of the first device light reaching the first polarizing beam splitter may be adjusted).
  • the optics may further comprise a dichroic beam splitter configured downstream of both the luminescent material and the diffuser, wherein the dichroic beam splitter may be configured to: (a) transmit the diffused device light and reflect the luminescent material light, or (b) reflect the diffused device light and transmit the luminescent material light.
  • the first device light provided to the diffuser may have essentially any polarization, i.e., there may be essentially no limitations to the polarization of the first device light provided to the diffuser.
  • the first polarizing beam splitter may thus even comprise a partially polarizing beam splitter.
  • the partially polarizing beam splitter may be configured to (redirect first device light comprising the first polarization such that at least 10%, like at least 20%, such as at least 30%, especially at least 40% may be reflected and at most 90%, like at most 80%, such as at most 70%, especially at most 60% may be transmitted.
  • the partially polarizing beam splitter may be partially (e.g. 80%) reflective and partially (e.g. 20%) transmissive for s-polarized light, whereas it may be essentially fully transmissive for p-polarized light (or vice versa).
  • the partially polarizing beam splitter may (even) be configured to be partially reflective for both the first linear polarization and the second linear polarization.
  • the partially polarizing beam splitter may be configured (i) to transmit part (such as e.g. selected between 10-90%, like between 30-70%) of the first device light comprising the first linear polarization and part (such as e.g. selected between 10-90%, like between 30-70%) of the first device light comprising the second linear polarization, and (ii) to reflect another part (such as e.g. selected between 10-90%, like between 30-70%) of the first device light comprising the first linear polarization and another part (such as e.g. selected between 10-90%, like between 30-70%) of the first device light comprising the second linear polarization.
  • the first polarizing beam splitter may comprise a partially polarizing beam splitter configured to partially transmit s-polarized first device light while being essentially fully reflective for p-polarized first device light.
  • the light generating system may further comprise the above described polarization converter.
  • the safety mechanism may comprise a small-angle diffuse reflector configured to transmit undiffused (i.e. unsafe) device light (optionally to a beam dump) and to reflect diffused device light to the light exit optionally via one or more optics.
  • undiffused device light i.e. unsafe
  • alternative safety mechanisms may be possible as well, such as e.g. comprising one or more light sensors and/or a reflective polarizer.
  • the luminescent material may be configured in the transmissive mode
  • the low pass dichroic filter may be configured to transmit the (blue) device light and reflect the converted (yellow-green) luminescent material light.
  • it may be desired to configure the luminescent material (comprised e.g. by a ceramic plate) onto (or into) a metallic support comprising a hole configured to allow the (blue) device light to pass.
  • one of the luminescent material and the diffuser may be configured in the reflective mode and the other one of the luminescent material and the diffuser may be configured in a transmissive mode.
  • Such embodiments may be beneficial as no additional optical elements (such as waveplates) are necessary to separate the undiffused device light from the diffused device light.
  • An additional benefit thereof may be that the polarization of the device light reaching the diffuser arrangement may be irrelevant of its function.
  • most elements of the previously described embodiments (where the luminescent material and diffuser are both configured in either the reflective of the transmissive mode) may be applied and/or combined here.
  • luminescent materials are selected from garnets and nitrides, especially doped with trivalent cerium or divalent europium, respectively.
  • nitride may also refer to oxynitride or nitridosilicate, etc.
  • the luminescent material(s) may be selected from silicates, especially doped with divalent europium.
  • the luminescent material is configured to convert at least part of the light source light into luminescent material light
  • the luminescent material may comprise a (garnet) luminescent material of the type AsBsOn Ce, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc.
  • the luminescent material light may e.g. be green light or yellow light (or in specific embodiments even orange (dependent upon the composition of the garnet and cerium concentration)).
  • 0.05-10% of the A elements comprise Ce, even more especially 0.05-5%, such as 0.1-5%.
  • 0.1-3% of the A elements comprise Ce, such as up to 2%, like selected from the range of 0.1-1.5%, such as at least above 0.5%.
  • a luminescent material comprises conversion material or is a conversion material.
  • a luminescent material converts light from a light source, such as the light source light, into secondary light (here the luminescent material light).
  • the luminescent material may comprise an organic group that converts the light, or a molecule that converts the light, or an inorganic group that converts the light, etc. Such groups (or molecule) may be indicated as converter element.
  • the garnet type material as indicated above, comprises cerium (Ce) as converter element. Cerium comprising garnets are well known in the art.
  • the luminescent material comprises a (first) luminescent material of the type AsEEOn Ce, wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc.
  • A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu.
  • B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al.
  • especially suitable luminescent materials are cerium comprising garnet materials.
  • Embodiments of garnets especially include A3B5O12 garnets, wherein A comprises at least yttrium or lutetium and wherein B comprises at least aluminum.
  • Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce.
  • B comprises aluminum (Al), however, B may also partly comprise gallium (Ga) and/or scandium (Sc) and/or indium (In), especially up to about 20% of Al, more especially up to about 10 % of Al (i.e.
  • the B ions essentially consist of 90 or more mole % of Al and 10 or less mole % of one or more of Ga, Sc, and In); B may especially comprise up to about 10% gallium.
  • B and O may at least partly be replaced by Si and N.
  • the element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and/or Tb are especially only present up to an amount of about 20% of A.
  • the garnet luminescent material comprises (Yi- x Lu x )3B50i2:Ce, wherein x is equal to or larger than 0 and equal to or smaller than 1.
  • Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the full correct formula could be (Yo.iLuo.89Ceo.oi)3A150i2.
  • Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.
  • the luminescent material (thus) comprises A3B5O12 wherein in specific embodiments at maximum 10% of B-0 may be replaced by Si-N.
  • x3 is selected from the range of 0.001-0.1.
  • xl>0 such as >0.2, like at least 0.8.
  • Garnets with Y may provide suitable spectral power distributions.
  • the material (Ba,Sr,Ca)2SisN8:Eu can also be indicated as NfcSis Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound Sr and/or Ba.
  • M consists of Sr and/or Ba (not taking into account the presence of Eu), especially 50 to 100%, more especially 50 to 90% Ba and 50 to 0%, especially 50 to 10% Sr, such as Bai.sSro.sSis Eu (i.e. 75 % Ba; 25% Sr).
  • Eu is introduced and replaces at least part of M, i.e. one or more of Ba, Sr, and Ca).
  • the material (Ba,Sr,Ca)2SisN8:Eu can also be indicated as NfcSis Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound Sr and/or Ba.
  • M consists of Sr and/or Ba (not taking into account the presence of Eu), especially 50 to 100%, more especially 50 to 90% Ba and 50 to 0%, especially 50 to 10% Sr, such as Bai.sSro.sSisNsEu (i.e. 75 % Ba; 25% Sr).
  • Eu is introduced and replaces at least part of M, i.e. one or more of Ba, Sr, and Ca).
  • the material (Ba,Sr,Ca)AlSiN3:Eu can also be indicated as MAlSi Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium.
  • Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca).
  • Eu in the above indicated luminescent materials is substantially or only in the divalent state, as is known to the person skilled in the art.
  • luminescent material herein especially relates to inorganic luminescent materials.
  • luminescent materials may be applied.
  • quantum dots and/or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc. etc.
  • quantum confinement structures should, in the context of the present application, be understood as e.g. quantum wells, quantum dots, quantum rods, tripods, tetrapods, or nano-wires, etcetera.
  • Organic phosphors can be used as well.
  • suitable organic phosphor materials are organic luminescent materials based on perylene derivatives, for example compounds sold under the name Lumogen® by BASF.
  • suitable compounds include, but are not limited to, Lumogen® Red F305, Lumogen® Orange F240, Lumogen® Yellow F083, and Lumogen® F170.
  • the luminescent material is selected from the group of divalent europium containing nitrides, divalent europium containing oxynitrides, divalent europium containing silicates, cerium comprising garnets, and quantum structures.
  • Quantum structures may e.g. comprise quantum dots or quantum rods (or other quantum type particles) (see above). Quantum structures may also comprise quantum wells. Quantum structures may also comprise photonic crystals.
  • the luminescent material may be comprised by a luminescent body.
  • the luminescent body may be a layer, like a self-supporting layer.
  • the luminescent body may also be a coating.
  • the luminescent body may also comprise a luminescent coating on a support (especially a light transmissive support in the transmissive mode).
  • the luminescent body may essentially be self-supporting.
  • the luminescent material may be provided as luminescent body, such as a luminescent single crystal, a luminescent glass, or a luminescent ceramic body. Such body may be indicated as “converter body” or “luminescent body”.
  • the luminescent body may be a luminescent single crystal or a luminescent ceramic body.
  • a cerium comprising garnet luminescent material may be provided as a luminescent single crystal or as a luminescent ceramic body.
  • the luminescent body may comprise a light transmissive body, wherein the luminescent material is embedded.
  • the luminescent body may comprise a glass body, with luminescent material embedded therein. Or, the glass as such may be luminescent.
  • the luminescent body may comprise a polymeric body, with luminescent material embedded therein.
  • the light generating system may comprise a second luminescent material (different from the above described (first) luminescent material).
  • the second luminescent material may especially, in embodiments, be configured to convert at least part of the first device light into second luminescent material light.
  • the second luminescent material may comprise one or more of Nao.sKo.sLisSiC ⁇ Eu 2 , MSi2C>2N2: Eu 2+ , wherein M comprises one or more of Ba, Sr, and Ca, Sr[BeeON4]:Eu 2+ , and MAhC ⁇ Eu 2 , wherein M comprises one or more of Ba, Sr, and Ca.
  • Such embodiments may be beneficial as the second luminescent material may improve the color point adjustability of the light generating system. Especially, such embodiments may result in color point tunability along a line that is substantially parallel to the BBL in a targeted range of color temperatures.
  • the light generating system may comprise optics.
  • optics may especially refer to (one or more) optical elements.
  • optical elements may refer to the same items.
  • the optics may include one or more of (specular or surface textured) mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffractive elements, gratings, dichroics, selectively reflective and/or selectively transmissive optics, arrays of one or more of the afore-mentioned, etc.
  • the optics may comprise one or more of a homogenizing optics, collimating optics, condensing optics, and reflecting optics.
  • the luminescent material light and the diffused laser light may be provided (e.g. by the dichroic beam splitter or the beam splitter arrangement as defined above) along the same optical path to the light exit, and the optics may comprise a beam homogenizer configured upstream of the light exit and configured to combine and homogenize the received light and to provide (homogenized white) system light to the light exit.
  • the condensing optics may comprise a first condensing optics configured (directly) upstream of the luminescent material and a second condensing optics configured (directly) upstream of the diffuser.
  • the first condensing optics and the second condensing optics may each comprise at least one positive lens.
  • the first condensing optics may comprise a first positive lens and a second smaller positive lens.
  • the smaller positive lens may especially be located between (relative to the propagation of light through the system) the first positive lens and the luminescent material or diffuser, respectively.
  • the term “light generating device” may also refer to a plurality of light generating devices which may provide device light having essentially the same spectral power distributions. In specific embodiments, the term “light generating device” may also refer to a plurality of light generating devices which may provide device light having different spectral power distributions.
  • the term “light source” may in principle relate to any light source known in the art. In a specific embodiment, the light source comprises a solid state LED light source (such as an LED or laser diode (or “diode laser”)).
  • the term “light source” may also relate to a plurality of light sources, such as 2-2000 (solid state) LED light sources. Hence, the term LED may also refer to a plurality of LEDs.
  • the term “light source” may in embodiments also refer to a so-called chips-on-board (COB) light source.
  • COB especially refers to LED chips in the form of a semiconductor chip that is neither encased nor connected but directly mounted onto a substrate, such as a PCB. Hence, a plurality of light emitting semiconductor light source may be configured on the same substrate.
  • a COB is a multi LED chip configured together as a single lighting module.
  • the term “light source” may also refer to a chip scaled package (CSP).
  • CSP chip scaled package
  • a CSP may comprise a single solid state die with provided thereon a luminescent material comprising layer.
  • the term “light source” may also refer to a midpower package.
  • a midpower package may comprise one or more solid state die(s).
  • the die(s) may be covered by a luminescent material comprising layer.
  • the die dimensions may be equal to or smaller than 2 mm, such as in the range of e.g. 0.2-2 mm.
  • the light source comprises a solid state light source.
  • the light source comprises a chip scale packaged LED.
  • the term “light source” may also especially refer to a small solid state light source, such as having a mini size or micro size.
  • the light sources may comprise one or more of mini LEDs and micro LEDs.
  • the light sources comprise micro LEDs or “microLEDs” or “pLEDs”.
  • mini size or mini LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm - 1 mm.
  • p size or micro LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm and smaller.
  • the light source comprises a laser light source.
  • the terms “laser” or “solid state laser” or “solid state material laser” may refer to one or more of cerium doped lithium strontium (or calcium) aluminum fluoride (Ce:LiSAF, Ce:LiCAF), chromium doped chrysoberyl (alexandrite) laser, chromium ZnSe (CrZnSe) laser, divalent samarium doped calcium fluoride (Sm:CaF2) laser, Er:YAG laser, erbium doped and erbium-ytterbium codoped glass lasers, F-Center laser, holmium YAG (Ho: YAG) laser, Nd:YAG laser, NdCrYAG laser, neodymium doped yttrium calcium oxoborate Nd:YCa4O(BO3)3 or Nd:YCOB, neodymium doped
  • the light generating device is configured to generate device light.
  • the device light may be blue light.
  • the terms “blue light” or “blue emission”, and similar terms, may especially relate to light having a wavelength in the range of about 440-490 nm (including some violet and cyan hues). However, intensity at shorter wavelengths may also be possible, such as within the wavelength range of 400-440 nm.
  • the device light may have a centroid wavelength (Xci) selected from the 400-490 nm wavelength range, more especially from the 400-480 nm wavelength range.
  • the device light has a peak wavelength selected from the blue wavelength range.
  • the light generating system may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, digital projection, or LCD backlighting.
  • the light generating system (or luminaire) may be part of or may be applied in e.g. optical communication systems or disinfection systems.
  • UV may especially refer to a wavelength selected from the range of 190-380 nm, such as 200-380 nm.
  • IR infrared
  • 780-3000 nm such as 780-2000 nm, e.g. a wavelength up to about 1500 nm, like a wavelength of at least 900 nm, though in specific embodiments other wavelengths may also be possible.
  • blue light or “blue emission” especially relates to light having a wavelength in the range of about 440-495 nm (including some violet and cyan hues).
  • green light or “green emission” especially relate to light having a wavelength in the range of about 495-570 nm.
  • yellow light or “yellow emission” especially relate to light having a wavelength in the range of about 570-590 nm.
  • range light or “orange emission” especially relate to light having a wavelength in the range of about 590- 620 nm.
  • red light or “red emission” especially relate to light having a wavelength in the range of about 620-780 nm.
  • the phrase “light having one or more wavelengths in a wavelength range” and similar phrases may especially indicate that the indicated light (or radiation) has a spectral power distribution with at least intensity or intensities at these one or more wavelengths in the indicate wavelength range.
  • a blue emitting solid state light source will have a spectral power distribution with intensities at one or more wavelengths in the 440-495 nm wavelength range.
  • the element may comprise the control system.
  • the control system and element may not be physically coupled. Control can be done via wired and/or wireless control.
  • the term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems.
  • a control system may comprise or may be functionally coupled to a user interface.
  • the control system may also be configured to receive and execute instructions from a remote control.
  • the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc.
  • the device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.
  • control system may (also) be configured to be controlled by an App on a remote device.
  • the control system of the lighting system may be a slave control system or control in a slave mode.
  • the lighting system may be identifiable with a code, especially a unique code for the respective lighting system.
  • the control system of the lighting system may be configured to be controlled by an external control system which has access to the lighting system on the basis of knowledge (input by a user interface of with an optical sensor (e.g. QR code reader) of the (unique) code.
  • the lighting system may also comprise means for communicating with other systems or devices, such as on the basis of Bluetooth, Thread, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.
  • a control system may be available, that is adapted to provide at least the controlling mode.
  • the choice of such modes may especially be executed via a user interface, though other options, like executing a mode in dependence of a sensor signal or a (time) scheme, may also be possible.
  • the operation mode may in embodiments also refer to a system, or apparatus, or device, that can only operate in a single operation mode (i.e. “on”, without further tunability).
  • control system may control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer.
  • timer may refer to a clock and/or a predetermined time scheme.
  • the invention also provides a lamp or a luminaire comprising the light generating system as defined herein.
  • the luminaire may further comprise a housing, optical elements, louvres, etc. etc...
  • the lamp or luminaire may further comprise a housing enclosing the light generating system.
  • the lamp or luminaire may comprise a light window in the housing or a housing opening, through which the system light may escape from the housing.
  • the invention also provides a projection device comprising the light generating system as defined herein.
  • a projection device or “projector” or “image projector” may be an optical device that projects an image (or moving images) onto a surface, such as e.g. a projection screen.
  • the projection device may include one or more light generating systems such as described herein.
  • the invention also provides a lighting device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system as defined herein.
  • the lighting device may comprise a housing or a carrier, configured to house or support, one or more elements of the light generating system.
  • the lighting device may comprise a housing or a carrier, configured to house or support one or more of the light generating devices, the luminescent material arrangement, the diffuser arrangement, and the optics.
  • the invention may thus comprise an optical wireless communication device comprising the light generating system.
  • one or more of the first light generating device and the second light generating device may especially comprise a high frequency laser and/or may be amplitude modulated.
  • especially the first light generating device may comprise a high frequency laser and/or may be amplitude modulated.
  • Such embodiments may be beneficial as in such embodiments the light generating device providing the fraction of (blue laser) diffused device light to the reflective diffuser is modulated, which is generally faster in their temporal response (i.e., in their decay rate) than luminescent material.
  • a lighting device or a lighting system may be configured to generate device light (or “lighting device light”) or system light (“or lighting system light”). As indicated above, the terms light and radiation may interchangeably be used.
  • the lighting device may comprise a light source.
  • the device light may in embodiments comprise one or more of light source light and converted light source light (such as luminescent material light).
  • the lighting system may comprise a light source.
  • the system light may in embodiments comprise one or more of light source light and converted light source light (such as luminescent material light).
  • Figs. 1-4 schematically depict some embodiments of the light generating system.
  • Fig. 5 schematically depicts some applications of the light generating system in lighting devices.
  • the schematic drawings are not necessarily to scale.
  • Fig. 1 schematically depicts an embodiment of the light generating system 1000 of the invention comprising light generating devices 100, a luminescent material arrangement 2000, a diffuser arrangement 7000, optics 500, a polarization control system 600, a light exit 1090, and a control system 300.
  • the light generating devices 100 may comprise (i) a first light generating device 110 configured to generate first device light 111, and (ii) a second light generating device 120 configured to generate second device light 121.
  • the first light generating device 110 and the second light generating device 120 (each) may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode.
  • the luminescent material arrangement 2000 may comprise a luminescent material 200 configured to convert at least part of first device light 111 and/or second device light 121 received by the luminescent material 200 into luminescent material light 201.
  • the luminescent material 200 may at least comprise a first luminescent material 210 of the type AsBsOn Ce.
  • A may comprise one or more of Y, La, Gd, Tb and Lu.
  • B may comprise one or more of Al, Ga, In and Sc.
  • the diffuser arrangement 7000 may comprise a diffuser 700 configured to diffuse first device light 111 received by the diffuser 700 into diffused device light 701.
  • the first device light 111 and the second device light 121 may propagate from the light generating devices 100 to one or more of the luminescent material arrangement 2000 and the diffuser arrangement 7000.
  • the light generating system 1000 may be configured such that the first device light 111 and the second device light 121 received by the first polarizing beam splitter 510 may comprise polarized light.
  • the optics 500 may comprise a first polarizing beam splitter 510 configured (a) downstream of the first light generating device 110 and second light generating device 120 and (b) upstream of both the luminescent material arrangement 2000 and the diffuser arrangement 7000.
  • the first polarizing beam splitter 510 may be configured to transmit (device) light received by the first polarizing beam splitter 510 and comprising a first linear polarization and to reflect (device) light received by the first polarizing beam splitter 510 and comprising a second linear polarization, different from the first linear polarization.
  • the first polarizing beam splitter 510 may be configured to reflect (device) light received by the first polarizing beam splitter 510 and comprising the first linear polarization and to transmit (device) light received by the first polarizing beam splitter 510 and comprising the second linear polarization.
  • the optics may further comprise a plurality of additional components.
  • reference 530 may refer to homogenizing optics
  • reference 540 may refer to collimating (and/or condensing) optics
  • reference 550 may refer to reflecting optics (such as e.g. a specular reflector).
  • the second polarization comprising first device light 111b may be transmitted towards the luminescent material 200 by the dichroic beam splitter 520.
  • the functionality of the dichroic beam splitter 520 is (substantially) independent of the polarization of (blue) device light 111,121 that is incident upon it.
  • the second device light 121 and the second polarization comprising first device light 111b may be converted into (yellow-green) luminescent material light 201.
  • the luminescent material light 201 may propagate from the luminescent material 200 back to the dichroic beam splitter 520, where it may be reflected to the light exit 1090.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • General Engineering & Computer Science (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Multimedia (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

The invention provides a light generating system (1000) comprising light generating devices (100), a luminescent material arrangement (2000), a diffuser arrangement (7000), optics (500), a polarization control system (600), and a control system (300); wherein: (A) the light generating devices (100) comprise (i) a first light generating device (110) configured to generate first device light (111), and (ii) a second light generating device (120) configured to generate second device light (121); (B) the luminescent material arrangement (2000) comprises a luminescent material (200) configured to convert at least part of first device light (111) and/or second device light (121) received by the luminescent material (200) into luminescent material light (201); (C) the diffuser arrangement (7000) comprises a diffuser (700) configured to diffuse first device light (111) received by the diffuser (700) into diffused device light (701); (D) the optics (500) comprise a first polarizing beam splitter (510) configured such that the first device light (111) and the second device light (121) received by the first polarizing beam splitter (510) comprise polarized light; (E) the first polarizing beam splitter (510) is configured (i) to transmit or reflect light received by the first polarizing beam splitter (510) and comprising a first linear polarization and (i) to reflect or transmit light received by the first polarizing beam splitter (510) and comprising a second linear polarization, different from the first linear polarization; (F) the polarization control system (600) is configured to control a polarization of the first device light (111) reaching the first polarizing beam splitter (510); (G) the optics (500) and the second light generating device (120) are configured such that (i) at least 90% of the second device light (121) received by the first polarizing beam splitter (510) is directed towards the luminescent material arrangement (2000), and (ii) in a first operational mode, in dependence of the polarization, at least part of the first device light (111) received by the first polarizing beam splitter (510) is directed towards the luminescent material arrangement (2000) and at least another part of the first device light (111) received by the first polarizing beam splitter (510) is directed towards the diffuser arrangement (7000); (H) the light generating system (1000) is configured to provide system light (1001) comprising one or more of at least part of the luminescent material light (201) and at least part of the diffused device light (701); and (I) the control system (300) is configured to control the system light (1001).

Description

Tunable CCT maximum output laser-phosphor engine with two laser banks
FIELD OF THE INVENTION
The invention relates to a light generating system. The invention further relates to a lighting device comprising the light generating system.
BACKGROUND OF THE INVENTION
Laser-phosphor based stage lighting fixtures are known in the art. For instance, WO2022143318 describes a light emitting device, comprising a first light source, a second light source, a dichroic mirror, a wavelength conversion apparatus, a first light path adjusting apparatus or a second light path adjusting apparatus, and a first scattering optical system. The light mixing effect of emergent light can be improved by using the first scattering optical system. Light emitted by the first light source is all used for exciting the wavelength conversion apparatus.
US2020/333699A1 discloses a light source apparatus that includes a first light source configured to emit light in a blue wavelength band, a second light source configured to emit light in a red wavelength band, a light amount ratio changer configured to change a light amount ratio between a first polarized light component and a second polarized light component in light of the blue wavelength band, a polarization beam splitter configured to split the first polarized light component and the second polarized light component, a wavelength converter configured to convert the light of the blue wavelength band obtained from the first polarized light component, into light in a red/green wavelength band, and a light combiner configured to combine the light.
US2022/091493A1 discloses a light source device that includes blue, green, and red laser light sources. A first retardation plate controls the polarization of blue laser light emitted from the blue laser light source and a polarizing beam splitter that separates the blue laser light whose polarization is controlled by the first retardation plate into a first blue laser light and a second blue laser light. A second retardation plate controls polarization of the second blue laser light separated by the polarizing beam splitter. A fluorescent plate is excited by the first blue laser light emits fluorescent light including a green component and a red component. A first dichroic mirror combines the second blue laser light and light emitted from the green and red laser light sources, to generate combined laser light. A dynamic diffuser plate diffuses the combined laser light to generate diffused laser light. A second dichroic mirror combines the diffused laser light and the fluorescent light.
SUMMARY OF THE INVENTION
High brightness light sources can be used in various applications including spots, stage-lighting, headlamps, home and office lighting, and automotive lighting. For this purpose, laser-phosphor technology can be used, wherein a laser provides laser light and a remote phosphor converts laser light into converted light. A relatively straightforward way to produce white light using lasers is to use (blue) laser light in combination with a (yellow) phosphor to generate phosphor converted light. Laser-phosphor systems may allow generation of high brightness light and may therefore be used in projection systems, including displays such as cinema projectors and projectors for home, school, and office applications, car front lighting, search lighting, stage lighting, architectural lighting, and special lighting applications. In general, a laser-phosphor light engine may be capable to generate only a single color point as defined by the luminescent converter. Creation of a product range providing different color points may be costly as it requires multiple unique components to be designed, qualified, produced, and kept in stock. In other cases, e.g. in RGB LCD-based projection systems, the maximum brightness is limited by the components used, the engine volume is large due to the many components, and the system cost are high due to the many dedicated components. A way to combine pump light and luminescent light may be to use a polarizing beam splitter for the pump light, by which part of the light is reflected to the luminescent material and part is transmitted to a diffuser. However, in general the diffused light may to a large degree be depolarized, which may result in relatively high losses of diffused blue light at a beam combiner where it is combined with the luminescent light into white output light. Hence, it may be desired to improve the performance of stage lighting fixtures.
Hence, it is an aspect of the invention to provide an alternative light generating system, which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.
According to a first aspect, the invention provides a light generating system comprising light generating devices, a luminescent material arrangement, a diffuser arrangement, optics, a polarization control system, a light exit, and a control system. In embodiments, the light generating devices may comprise a first light generating device configured to generate first device light and a second light generating device configured to generate second device light. Especially, in embodiments, the first light generating device may comprise a first solid state light source configured to generate first light source light. Similarly, in embodiments, the first light generating device may comprise a first solid state light source configured to generate first light source light. Especially, in embodiments, the first light generating device and the second light generating device may (each) comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction lightemitting diode. Further, in embodiments, the luminescent material arrangement may comprise a luminescent material. In embodiments, the luminescent material may be configured to convert at least part of first device light and/or second device light received by the luminescent material into luminescent material light. Yet further, in embodiments, the diffuser arrangement may comprise a diffuser. In embodiments, the diffuser may be configured to diffuse first device light received by the diffuser into diffused device light. Moreover, in embodiments, the optics may comprise a first polarizing beam splitter. The first polarizing beam splitter may be configured downstream of the first light generating device and the second light generating device. Additionally, in embodiments, the first polarizing beam splitter may be configured upstream of both the luminescent material arrangement and the diffuser arrangement. The light generating system may, in embodiments, be configured such that the first device light and the second device light received by the first polarizing beam splitter may comprise polarized light. The first polarizing beam splitter may be configured to transmit or reflect light (received by the first polarizing beam splitter) in dependence of its polarization. Especially, in embodiments, the first polarizing beam splitter may be configured to transmit (device) light received by the first polarizing beam splitter and (said (device) light) comprising a first linear polarization. In such embodiments, the first polarizing beam splitter may be configured to reflect (device) light received by the first polarizing beam splitter and (said (device) light) comprising a second linear polarization, different from the first linear polarization. Alternatively, in embodiments, the first polarizing beam splitter may be configured to reflect (device) light received by the first polarizing beam splitter and (said (device) light) comprising the first linear polarization. In such embodiments, the first polarizing beam splitter may be configured to transmit (device) light received by the first polarizing beam splitter and (said (device) light) comprising the second linear polarization. Furthermore, in embodiments, the polarization control system may be configured to control a polarization of the first device light reaching the first polarizing beam splitter. Moreover, in embodiments, the optics and the second light generating device may be configured such that at least 90% of the second device light received by the first polarizing beam splitter may be directed towards the luminescent material arrangement. Additionally or alternatively, in embodiments, the optics and the second light generating device may be configured such that in a first operational mode of the light generating system in dependence of the polarization at least part of the first device light received by the first polarizing beam splitter may be directed towards the luminescent material arrangement. Similarly, in such embodiments, the optics and the second light generating device may be configured such that in a first operational mode of the light generating system in dependence of the polarization at least another part of the first device light received by the first polarizing beam splitter may be directed towards the diffuser arrangement. Yet further, in embodiments, the optics may be configured such that the luminescent material light may propagate via part of the optics to the light exit. Analogously, in embodiments, the optics may be configured such that the diffused device light may propagate via part of the optics to the light exit. In embodiments, the light generating system may be configured to provide in the first operational mode of the light generating system at the light exit system light. Hence, in embodiments, the system light may comprise one or more of at least part of the luminescent material light and at least part of the diffused device light. Furthermore, in embodiments, the control system may be configured to control a spectral power distribution of the system light (by controlling the polarization of the (first) device light). In such embodiments, the control system may especially do so by controlling one or more of the polarization control system and the light generating devices. Hence, in embodiments, the invention provides a light generating system comprising light generating devices, a luminescent material arrangement, a diffuser arrangement, optics, a polarization control system, a light exit, and a control system; wherein: (A) the light generating devices may comprise (i) a first light generating device configured to generate first device light, and (ii) a second light generating device configured to generate second device light; wherein the first light generating device and the second light generating device may (each) comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode; (B) the luminescent material arrangement may comprise a luminescent material configured to convert at least part of first device light and/or second device light received by the luminescent material into luminescent material light; (C) the diffuser arrangement may comprise a diffuser configured to diffuse first device light received by the diffuser into diffused device light; (D) the optics may comprise a first polarizing beam splitter configured downstream of the first light generating device and second light generating device and upstream of both the luminescent material arrangement and the diffuser arrangement; wherein the light generating system may be configured such that the first device light and the second device light received by the first polarizing beam splitter may comprise polarized light; (E) the first polarizing beam splitter may be configured (ia) to transmit (device) light received by the first polarizing beam splitter and comprising a first linear polarization and (ib) to reflect (device) light received by the first polarizing beam splitter and comprising a second linear polarization, different from the first linear polarization, or (iia) to reflect (device) light received by the first polarizing beam splitter and comprising the first linear polarization and (iib) to transmit (device) light received by the first polarizing beam splitter and comprising the second linear polarization; (F) the polarization control system may be configured to control a polarization of the first device light reaching the first polarizing beam splitter; (G) the optics and the second light generating device may be configured such that (i) at least 90% of the second device light received by the first polarizing beam splitter may be directed towards the luminescent material arrangement, and (ii) in a first operational mode of the light generating system in dependence of the polarization at least part of the first device light received by the first polarizing beam splitter may be directed towards the luminescent material arrangement and at least another part of the first device light received by the first polarizing beam splitter may be directed towards the diffuser arrangement; the optics may be configured further such that the luminescent material light may propagate via part of the optics to the light exit and such that the diffused device light may propagate via part of the optics to the light exit; (H) the light generating system may be configured to provide in the first operational mode of the light generating system at the light exit system light comprising one or more of at least part of the luminescent material light and at least part of the diffused device light; and (I) the control system may be configured to control a spectral power distribution of the system light by controlling one or more of the polarization control system and the light generating devices. The first device light has a first peak wavelength (Xpi) selected from the wavelength range of 440-480 nm and the second device light has a second peak wavelength (Xp2) selected from the wavelength range of 440-480 nm. In an operational mode of the light generating system the system light is white light having a correlated color temperature selected from the range of 2700-10000 K and a color rendering index of at least 65.
With such system, a high power light generating system may be provided. Further, such system may allow control of spectral power distribution of the system light (of a high power system), in dependence of the controllable polarization of light.. Yet, such system may in a safe way provide high power light. The system may be relatively compact. Yet, thermal management of the luminescent material may also be provided with this system. In addition to high optical power, the system may also provide high radiance (or luminance), i.e., a high optical power density of the source.
Further, such a light generating system may provide a light engine configured to make effective use of its light sources. Further such a system can be easily factory- calibrated with respect to a requested color point. Additionally, for such a light generating system the color point may easily be adjusted by the user, based on maximum output power of two laser light sources for any of the color points selected in a predetermined range of white light output color points (e.g. 6000 - 10000 K), while providing relatively highly efficient collection of all the spectral contributions to the output light, resulting in a high efficiency high brightness white light engine.
The light generating system (or “system”) may thus comprise light generating devices, a luminescent material arrangement, a diffuser arrangement, optics, a polarization control system, a light exit, and a control system. The light generating system may thus apply two (or more) light generating devices that may both be operated at a constant power while the system may be set to any correlated color temperature (CCT) in a predetermined range of CCTs. Here below, embodiments of the different components of the light generating system will be described in further detail.
The light generating devices may be configured to generate device light. In embodiments, the light generating devices may comprise (at least) a first light generating device and a second light generating device. The first light generating device may, in embodiments, be configured to generate first device light. Therefore, in embodiments, the first light generating device may comprise a first light source. The first light source may be essentially any light source, see also further below. Especially, in embodiments, the (first light source of the) first light generating device may comprise a first solid state light source. Hence, in embodiments, the first light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode (LED). The first light generating device may herein also comprise a plurality of first (solid state) light sources. Especially, in specific embodiments, the first light generating device may comprise a first laser bank comprising a plurality of first lasers. A laser banks may comprise a relatively dense assembly of multiple laser diodes on a shared substrate provided with collimating optics, such as collimating lenses comprising one lens per laser diode. The use of laser banks may especially be convenient for projecting a beam of high power laser light onto a luminescent converter without the need for using an inverse beam expander.
Further, in embodiments, the first light generating device may especially be configured to generate first device light having a first peak wavelength (Xpi). Especially, in embodiments, the first device light may have a first peak wavelength (Xpi) selected from the wavelength range of 430-490 nm, such as from the range of 440-480 nm, like from the range of 445-475 nm. Hence, in embodiments, the first device light may be blue light.
Analogously to the first light generating device, in embodiments, the second light generating device may be configured to generate second device light. Therefore, in embodiments, the second light generating device may comprise a second light source. The second light source may be essentially any light source, see also further below. Especially, in embodiments, the (second light source of the) second light generating device may comprise a second solid state light source. Hence, in embodiments, the second light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multijunction light-emitting diode (LED). In embodiments, the second light generating device may comprise essentially the same light generating device as the first light generating device. However, in other embodiments, the first light generating device and the second light generating device may be substantially different. The second light generating device may herein also comprise a plurality of second (solid state) light sources. Especially, in specific embodiments, the second light generating device may comprise a second laser bank comprising a plurality of second lasers.
Further, in embodiments, the second light generating device may especially be configured to generate second device light having a second peak wavelength (Xp2). Especially, in embodiments, the second device light may have a second peak wavelength (Xp2) selected from the wavelength range of 430-490 nm, such as from the range of 440-480 nm, like from the range of 445-475 nm. Hence, in embodiments, the second device light may be blue light.
In embodiments, the first light generating device and the second light generating device may be configured to provide first device light and second device light, respectively, to the optics. The optics may, in embodiments, comprise a first polarizing beam splitter. In embodiments, (in an operational mode of the light generating system) the first polarizing beam splitter may be configured downstream of both the first light generating device and the second light generating device. In other words, in embodiments, in an operational mode of the light generating system the first polarizing beam splitter may be configured in a light-receiving relationship with both the first device light and the second device light. The terms “upstream” and “downstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here the especially the light source), wherein relative to a first position within a beam of light from the light generating means, a second position in the beam of light closer to the light generating means is “upstream”, and a third position within the beam of light further away from the light generating means is “downstream”.
In embodiments, the device light received by the first polarizing beam splitter may especially be polarized light. Hence, in embodiments, the light generating system may be configured such that the first device light received by the first polarizing beam splitter may comprise polarized light. In embodiments, the first device light received by the first polarizing beam splitter may especially comprise linearly polarized first device light, such as e.g. p-polarized first device light and/or s-polarized first device light. The first light generating device may, in embodiments, be configured to provide (linearly) polarized first device light. Additionally or alternatively, in embodiments, the first device light may be unpolarized light and the polarization control system (see also further below) may be configured such that (linearly) polarized first device light may be provided to the first polarizing beam splitter. In such embodiments, the polarization control system may especially comprise a polarizer configured to change the polarization of device light received by the polarizer. For example, in embodiments, the first light generating device may be configured to generate first device light comprising a circular polarization and to provide said circularly polarized first device light to the polarizer (such as e.g. a X/4 waveplate). In such embodiments, the polarizer may be configured to convert the circularly polarized first device light into first device light comprising a ratio of first device light comprising the first linear polarization relative to first device light comprising the second linear polarization.
The phrase “... light received by ...”, and similar phrases, such as “device light received by the first polarizing beam splitter” may especially indicate that when the light is actually received by an item, an action may take place. The action may in embodiments be one or more of conversion, reflection, and transmission. Further, the action may also include refraction. Whether or not such item receives light may e.g. depend on e.g. a controlling mode (for instance whether or not a light generating device provides light).
Similarly, in embodiments, the device light received by the second polarizing beam splitter may especially be polarized light. Hence, in embodiments, the light generating system may be configured such that the second device light received by the first polarizing beam splitter may comprise polarized light. In embodiments, the second device light received by the first polarizing beam splitter may especially comprise linearly polarized second device light, such as e.g. p-polarized second device light and/or s-polarized second device light. The second light generating device may, in embodiments, be configured to provide (linearly) polarized second device light. Additionally or alternatively, in embodiments, the second device light may be unpolarized light and the polarization control system (see also further below) may be configured such that (linearly) polarized second device light may be provided to the first polarizing beam splitter.
The first polarizing beam splitter may further, in embodiments, be configured upstream of the luminescent material arrangement. Additionally or alternatively, in embodiments, the first polarizing beam splitter may (also) be configured upstream of the diffuser arrangement. Especially, in embodiments, in an operational mode of the light generating system the first polarizing beam splitter may be configured upstream of both the luminescent material arrangement and the diffuser arrangement. As such, in embodiments, the luminescent material arrangement and the diffuser arrangement may both be configured in a light-receiving relationship with the first polarizing beam splitter. Especially, in embodiments, the first polarizing beam splitter may be configured to direct device light to the luminescent material arrangement and the diffuser arrangement.
In embodiments, the first polarizing beam splitter may be configured to transmit or reflect (device) light in dependence of its polarization. Especially, in embodiments, the first polarizing beam splitter may be configured to transmit (device) light received by the first polarizing beam splitter and (said (device) light) comprising a first linear polarization. Especially, in embodiments, the first polarizing beam splitter may be configured to transmit at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95%, including 100% of the light (comprising the first linear polarization) received by the first polarizing beam splitter. Further, in such embodiments, the first polarizing beam splitter may be configured to reflect light received by the first polarizing beam splitter and (said (device) light) comprising a second linear polarization. Especially, in embodiments, the first polarizing beam splitter may be configured to reflect at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95%, including 100% of the light (comprising the second linear polarization) received by the first polarizing beam splitter. Alternatively, in embodiments, the first polarizing beam splitter may be configured to reflect light received by the first polarizing beam splitter and (said (device) light) comprising the first linear polarization. Especially, in embodiments, the first polarizing beam splitter may be configured to reflect at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95%, including 100% of the light (comprising the first linear polarization) received by the first polarizing beam splitter. Further, in such embodiments, the first polarizing beam splitter may be configured to transmit light received by the first polarizing beam splitter and (said (device) light) comprising the second linear polarization. Especially, in embodiments, the first polarizing beam splitter may be configured to transmit at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95%, including 100% of the light (comprising the second linear polarization) received by the first polarizing beam splitter. Note that, in embodiments, the first polarizing beam splitter may also function as a beam combiner (e.g. configured to combine (along a same optical path) a part of the first device light with the second device light).
In embodiments, the second linear polarization may especially be different from the first linear polarization. Especially, in some embodiments the first linear polarization may be p-polarization and the second linear polarization may be s-polarization. In other embodiments, the first polarization may be s-polarization and the second polarization may be p-polarization. Herein, the terms “p-polarization” and “s-polarization” may especially refer to the polarization of light when incident on (a light-receiving plane of) the lightreceiving element, such as e.g. the first polarizing beam splitter. Hence, in embodiments, the first polarizing beam splitter may be configured to transmit p-polarized light received by the first polarizing beam splitter and to reflect s-polarized light received by the first polarizing beam splitter. Additionally or alternatively, in embodiments, the first polarizing beam splitter may be configured to transmit s-polarized light received by the first polarizing beam splitter and to reflect p-polarized light received by the first polarizing beam splitter. Especially, in some such embodiments, the first polarizing beam splitter may be configured such that a ratio of the amount of s-polarized light being transmitted relative to the amount of p-polarized light being transmitted may be <0.9, such as <0.8, like <0.6, especially <0.4. Similarly, in some such embodiments, the first polarizing beam splitter may be configured such that a ratio of the amount of p-polarized light being reflected relative to the amount of s-polarized light being reflected may be <0.9, such as <0.8, like <0.6, especially <0.4. Yet alternatively, in embodiments, the first polarizing beam splitter may be configured to partially transmit and partially reflect one or more of light comprising the first linear polarization and light comprising the second linear polarization, see also further below. Amounts of light may be based on the spectral power (of the light) (e.g. Watts). As indicated above, in embodiments, the polarization control system may be configured to control a polarization of the first device light reaching the first polarizing beam splitter. Especially, in embodiments, the polarization control system may be configured such that xl% of first device light comprising the first linear polarization and yl% of first device light comprising the second linear polarization may be provided to the first polarizing beam splitter. Herein, in embodiments, xl and yl may be individually selected from the range of 0- 100%, such as from the range of 10-90%, like from the range of 20-80%. In some embodiments, the polarization control system may be configured such that only first device light comprising the first linear polarization may be provided to the first polarizing beam splitter, i.e., xl=100% and yl=0%. In other embodiments, the polarization control system may be configured such that only first device light comprising the second linear polarization may be provided to the first polarizing beam splitter, i.e., yl=100% and xl=0%. In yet other embodiments, the polarization control system may be configured such that a combination of first device light comprising the first linear polarization and first device light comprising the second linear polarization may be provided to the first polarizing beam splitter, i.e., xl )%, yl )%, and xl+yl=100%. For example, in embodiments, the polarization control system may be configured such that x=70% of first device light comprising the first linear polarization and y=30% of first device light comprising the second linear polarization may be provided to the first polarizing beam splitter, or vice versa (i.e., xl=30% and yl=70%).
Hence, in embodiments, the polarization control system may be configured to control a polarization of the first device light reaching the first polarizing beam splitter. Especially, in embodiments, the polarization control system may be configured to control a polarization of the first device light reaching the first polarizing beam splitter, such that (selected from the range of) 50-98% of the first device light received by the first polarizing beam splitter may be directed to the luminescent material arrangement. More especially, in embodiments, at least 50%, such as at least 60%, especially at least 70%, like at least 80% of the first device light received by the first polarizing beam splitter may be directed to the luminescent material arrangement. Further, in embodiments, at most 99%, such as at most 98%, like at most 95%, especially at most 90%, more especially at most 80% of the first device light received by the first polarizing beam splitter may be directed to the luminescent material arrangement. Hence, in embodiments, the polarization control system may be configured to control a polarization of the first device light reaching the first polarizing beam splitter, such that (selected from the range of) 50-98% of the first device light received by the first polarizing beam splitter may be directed to the luminescent material arrangement. Hence, in embodiments, in a first operational mode of the light generating system the first polarizing beam splitter may be configured to direct part of (or even essentially all of) the first device light to the luminescent material arrangement. Additionally or alternatively, in embodiments, in a first operational mode of the light generating system the first polarizing beam splitter may be configured to direct part of (or even essentially all of) the first device light to the diffuser arrangement. Note that herein, in embodiments, the light generating system may be operated in a plurality of (different) operational modes, such as the first operational mode indicated above. Furthermore, in embodiments, the term “first operational mode” may herein also refer to a plurality of (different) first operational modes. Especially, in embodiments, in a first operational mode of the light generating system the first polarizing beam splitter may be configured to direct at most 50%, such as at most 40%, like at most 30%, especially at most 20%, more especially at most 10%, including 0% of the first device light to the diffuser arrangement. However, in alternative embodiments, in a first operational mode of the light generating system the first polarizing beam splitter may be configured to direct at least 50%, such as at least 60%, like at least 70%, especially at least 80%, more especially at least 90%, including 100% of the first device light to the diffuser arrangement. The first polarizing beam splitter may thus, in embodiments, be configured to (re-)direct the (first) device light received by the first polarizing beam splitter in dependence of its polarization. Hence, in embodiments, in a first operational mode of the light generating system in dependence of the polarization at least part of the first device light received by the first polarizing beam splitter may be directed towards the luminescent material arrangement and/or at least (another) part of the first device light received by the first polarizing beam splitter may be directed towards the diffuser arrangement.
Furthermore, in embodiments, the optics together with the second light generating device may be configured such that at least 70%, such as at least 80%, like at least 90%, especially at least 95%, more especially at least 98%, including 100% of the second device light received by the first polarizing beam splitter may be directed towards the luminescent material arrangement. Hence, in embodiments, the optics and the second light generating device may be configured such that most of the second device light, especially essentially all of the second device light propagating from the first polarizing beam splitter, may be directed to the luminescent material arrangement (by the first polarizing beam splitter).
In embodiments, the luminescent material arrangement may comprise a luminescent material. The luminescent material is configured to convert at least part of first radiation (selected from one or more of UV radiation and visible radiation), into luminescent material light. Especially, in embodiments the luminescent material may be configured to convert at least part of blue light (as radiation) into luminescent material light. Especially when blue light is partly converted, the blue light may be used as source of blue light (for the device light) and as excitation light that can be converted by the luminescent material. The first radiation may especially be provided by a (solid state) light source. Hence, in embodiments, the luminescent material may be configured to convert at least part of first device light received by the luminescent material (arrangement) into luminescent material light. As described above, in embodiments, the (part of) first device light that may be received by the luminescent material may depend on the polarization (as controlled by the polarization control system) of the first device light reaching the first polarizing beam splitter. Especially, in embodiments, the luminescent material may be configured to convert at least 50%, such as at least 60%, like at least 70%, especially at least 80%, more especially at least 90%, including 100% of the first device light received by the luminescent material (arrangement) into luminescent material light. Additionally or alternatively, in embodiments, the luminescent material may be configured to convert at least part of second device light received by the luminescent material into luminescent material light. Especially, in embodiments, the luminescent material may be configured to convert at least 50%, such as at least 60%, like at least 70%, especially at least 80%, more especially at least 90%, including 100% of the second device light received by the luminescent material (arrangement) into luminescent material light.
When different luminescent materials are applied, one or more luminescent materials may be configured to convert incident light into one or more of green and yellow luminescent material light, and one or more other luminescent materials may be configured to convert incident light into one or more of orange and red luminescent material light.
The term “luminescent material” especially refers to a material that can convert first radiati on, (especially one or more of UV radiation and blue radiation,) into second radiation. In general, the first radiation and second radiation have different spectral power distributions. Hence, instead of the term “luminescent material”, also the terms “luminescent converter” or “converter” may be applied. Further, instead of the term “luminescent material” also the term “phosphor” may be applied. These terms are known to the person skilled in the art. In general, the second radiation has a spectral power distribution at larger wavelengths than the first radiation, which is the case in the so-called downconversion. In specific embodiments, however the second radiation has a spectral power distribution with intensity at smaller wavelengths than the first radiation, which is the case in the so-called up-conversion.
In embodiments, the “luminescent material” may especially refer to a material that can convert radiation into e.g. visible and/or infrared light. For instance, in embodiments the luminescent material may be able to convert one or more of UV radiation and blue radiation, into visible light. The luminescent material may in specific embodiments also convert radiation into infrared radiation (IR). Hence, upon excitation with radiation, the luminescent material emits radiation. In general, the luminescent material will be a down converter, i.e. radiation of a smaller wavelength is converted into radiation with a larger wavelength (Xex<Xem), though in specific embodiments the luminescent material may comprise up-converter luminescent material, i.e. radiation of a larger wavelength is converted into radiation with a smaller wavelength ( x> m).
In embodiments, the term “luminescence” may refer to phosphorescence. In embodiments, the term “luminescence” may also refer to fluorescence. Instead of the term “luminescence”, also the term “emission” may be applied. Hence, the terms “first radiation” and “second radiation” may refer to excitation radiation and emission (radiation), respectively. Likewise, the term “luminescent material” may in embodiments refer to phosphorescence and/or fluorescence.
The term “luminescent material” may also refer to a plurality of different luminescent materials. Hence, the term “luminescent material” may in specific embodiments also refer to a luminescent material composition. The term “luminescent material” herein may also refer to a material comprising a luminescent material, such as a light transmissive host comprising the luminescent material. Examples of possible luminescent materials are indicated further below.
As indicated above, in embodiments, part of the device light received by the first polarizing beam splitter may be directed to the diffuser arrangement. In embodiments, the diffuser arrangement may comprise a (surface) diffuser. Especially, in embodiments, the diffuser may comprise an element comprising a light-diffusive material, such as e.g. a silica, ground glass, a polymeric material, a ceramic material, a metal(lic) material, a white material, and a rough-surfaced material. The diffuser may, in embodiments, be configured to diffuse first device light received by the diffuser into diffused (first) device light. Especially, in embodiments, the diffuser may be configured to diffuse at least 50%, such as at least 60%, like at least 70%, especially at least 80%, more especially at least 90%, including 100% of the first device light received by the diffuser (arrangement) into diffused device light. In embodiments, the diffuser may especially comprise a substantially polarization maintaining diffuser, i.e., the diffuser may be configured to substantially maintain the polarization of the incident light upon diffusion (and in some embodiments reflection). Therefore, in embodiments, the diffuser may comprise a metal coated surface textured glass substrate mounted on a heat conductive material such as e.g. a metal or a ceramic. In such embodiments, the heat conductive material may be configured to conduct away heat that may be generated in the diffuser due to some absorption of incident device light.
Hence, in embodiments, the light generating system may be configured to generate luminescent material light and/or diffused device light. In embodiments, the optics may be configured such that the luminescent material light may propagate via part of the optics to the light exit. For example, in some embodiments, the luminescent material light may propagate via one or more reflectors (comprised by the optics) to the light exit. Additionally or alternatively, in some embodiments, the luminescent material light may propagate via a second polarizing beam splitter (comprised by the optics, see also further below) to the light exit. Additionally or alternatively, in some embodiments, the luminescent material light may propagate via a dichroic beam splitter (comprised by the optics, see also further below) to the light exit. Similarly, in embodiments, the optics may be configured such that the diffused device light may propagate via part of the optics to the light exit. For example, in some embodiments, the diffused device light may propagate via one or more reflectors (comprised by the optics) to the light exit. Additionally or alternatively, in some embodiments, the diffused device light may propagate via a second polarizing beam splitter (comprised by the optics, see also further below) to the light exit. Additionally or alternatively, in some embodiments, the diffused device light may propagate via a dichroic beam splitter (comprised by the optics, see also further below) to the light exit.
Herein, the light exit may refer to a position where system light escapes from the light generating system. This may, in embodiments, be a light transmissive window or an opening (in the system). The light transmissive window may in embodiments be provided by an optical component.
The light generating system may thus, in embodiments, be configured to provide in the first operational mode of the light generating system at the light exit one or more of luminescent material light and diffused device light. In other words, in such embodiments, (the system light comprising) one or more of luminescent material light and diffused device light may emanate away from the light generating system via the light exit. In embodiments, the light generating system may especially be configured to generate system light comprising one or more of at least part of the luminescent material light and at least part of the diffused device light. Hence, in embodiments, the light generating system may be configured to provide in the first operational mode of the light generating system at the light exit system light comprising one or more of at least part of the luminescent material light and at least part of the diffused device light.
In embodiments, the control system may be configured to control the system light. Especially, in embodiments, the control system may be configured to control a spectral power distribution of the system light. The control system may, in embodiments, be configured to control said spectral power distribution by controlling the polarization control system. Hence, in such embodiments, the amount of first device light comprising the first linear polarization and first device light comprising the second linear polarization may be controlled by the control system, which may in turn be controlling the polarization control system. Additionally or alternatively, in embodiments, the control system may be configured to control said spectral power distribution by controlling the light generating devices. Especially, in such embodiments, the control system may be configured to control the polarization of at least the first light generating device. Hence, in such embodiments, the amount of first device light comprising the first linear polarization and first device light comprising the second linear polarization may be controlled by the control system, which may in turn be controlling the light generating devices. In some embodiments, the control system may especially be configured to control the spectral power distribution of the system light by controlling both the polarization control system and the light generating devices.
In an operational mode of the light generating system, in embodiments, the system light may thus comprise (yellow-green) luminescent material light and (blue) diffused device light. Hence, in such embodiments, the system light may be white light. Especially, in embodiments, in an operational mode of the light generating system the system light may be white light having a correlated color temperature selected from the range of 2000-12000 K, such as from the range of 2700-10000 K, especially from the range of 6500-8000 K. Additionally or alternatively, in embodiments, in an operational mode of the light generating system the system light may be white light having a color rendering index of at least 60, such as at least 65, like at least 70, especially at least 80. Such embodiments may especially be beneficial for application of the light generating system in entertainment (spot) lighting applications.
The term “white light”, and similar terms, herein, is known to the person skilled in the art. It may especially relate to light having a correlated color temperature (CCT) between about 1800 K and 20000 K, such as between 2000 and 20000 K, especially 2700- 20000 K, for general lighting especially in the range of about 2000-7000 K, such as in the range of 2700 K and 6500 K. In embodiments, e.g. for backlighting purposes, or for other purposes, the correlated color temperature (CCT) may especially be in the range of about 7000 K and 20000 K. Yet further, in embodiments the correlated color temperature (CCT) is especially within about 15 SDCM (standard deviation of color matching) from the BBL (black body locus), especially within about 10 SDCM from the BBL, even more especially within about 5 SDCM from the BBL.
In specific embodiments, the correlated color temperature (CCT) may be selected from the range of 6000-12000 K, like selected from the range of 7000-12000 K, like at least 8000 K. Yet further, in embodiments the correlated color temperature (CCT) may be selected from the range of 6000-12000 K, like selected from the range of 7000-12000 K, in combination with a CRI of at least 70.
In an embodiment, the light source may also provide light source light having a correlated color temperature (CCT) between about 5000 and 20000 K, e.g. direct phosphor converted LEDs (blue light emitting diode with thin layer of phosphor for e.g. obtaining of 10000 K). Hence, in a specific embodiment the light source is configured to provide light source light with a correlated color temperature in the range of 5000-20000 K, even more especially in the range of 6000-20000 K, such as 8000-20000 K. An advantage of the relative high color temperature may be that there may be a relatively high blue component in the light source light.
In embodiments, an element, such as e.g. the luminescent material and the diffuser, may be configured in either a reflective mode or a transmissive mode. Especially, the luminescent material and/or the diffuser may be configured in the transmissive mode. In the transmissive mode, it may be relatively easy to have light source light admixed in the luminescent material light and/or the diffused device light, respectively, which may be useful for generating the desirable spectral power distribution. Hence, would any device light escape from the system, in embodiments, this may only escape via transmission through the luminescent material and/or the diffuser. In the reflective mode, thermal management may be easier, as a substantial part of the luminescent material and/or the diffuser may be in thermal contact with a thermally conductive element, like a heatsink or heat spreader. Hence, would any device light escape from the system, in embodiments, this may only escape via reflection at the luminescent material and/or the diffuser. In some embodiments, the luminescent material and the diffuser may thus both be configured in the reflective mode. Here below, such embodiments where the luminescent material and the diffuser are both configured in the reflective mode are described in further detail. Especially, in such embodiments, the diffuser may comprise a polarization maintaining diffuser. Such embodiments may be beneficial as depolarization at the diffuser may be reduced, therewith improving the efficiency of the contribution of the diffuser arrangement to the system light.
Further, in embodiments, the diffuser arrangement may comprise a X/4 waveplate. As known from the art, a waveplate or retarder is an optical device that alters the polarization state of a light wave travelling through it. A halfwave plate may shift the polarization direction of linearly polarized light (especially from s to p or from p to s polarization), and a quarter-wave plate may convert linearly polarized light into elliptically (such as especially circularly) polarized light (and vice versa). The X/4 waveplate may especially be configured between (relative to the propagation of light through the system) the first polarizing beam splitter and the diffuser. In embodiments, the first polarizing beam splitter may thus be configured to direct first device light received by the first polarizing beam splitter and comprising (either) the first linear polarization or the second linear polarization (optionally via optics) to the X/4 waveplate. The X/4 waveplate may, in embodiments, be configured to convert first device light received by the X/4 waveplate comprising a linear polarization into first device light having a (first) circular polarization. At the diffuser, in embodiments, the first device light having the (first) circular polarization may be diffused into diffused device light having a second circular polarization. Therefore, in embodiments, the X/4 waveplate may also be configured to convert diffused device light received by the X/4 waveplate (via the diffuser) and having the (second) circular polarization into diffused device light comprising a linear polarization. For example, in embodiments, p- polarized first device light may be directed by the first polarizing beam splitter to the X/4 waveplate. In such embodiments, the X/4 waveplate may be configured to convert the p- polarized first device light into left-handed circularly polarized first device light. Further, in such embodiments, the diffuser may be configured to diffuse the left-handed circularly polarized first device light received by the diffuser into right-handed circularly polarized diffused device light. The X/4 waveplate may then, in embodiments, be configured to convert the right-handed circularly polarized diffused device light received by the X/4 waveplate (back) to linearly polarized light, especially to s-polarized diffused device light. However, in embodiments, different polarizations and conversions from the example described here may be possible too, such as e.g. starting from s-polarized first device light. Hence, in embodiments, the luminescent material and the diffuser may both be configured in the reflective mode; wherein the diffuser may comprise a polarization maintaining diffuser, and wherein the diffuser arrangement may further comprise a X/4 waveplate configured between the first polarizing beam splitter and the diffuser, wherein the first polarizing beam splitter may be configured to direct first device light received by the first polarizing beam splitter and comprising the first linear polarization or the second linear polarization (optionally via optics) to the X/4 waveplate, wherein the X/4 waveplate may be configured to (i) convert first device light received by the X/4 waveplate and comprising a linear polarization into first device light having a (first) circular polarization, and (ii) convert diffused device light received by the X/4 waveplate (via the diffuser) and comprising a (second) circular polarization into diffused device light comprising a linear polarization.
In an operational mode of the light generating system (blue) diffused device light and (yellow-green) luminescent material light may thus propagate through the system. Therefore, in embodiments, the optics may further comprise a (first) dichroic beam splitter. In embodiments, the dichroic beam splitter may especially be configured between (relative to the propagation of light through the system) the first polarizing beam splitter and the luminescent material. Especially, in embodiments, the dichroic beam splitter may be configured in a light-receiving relationship with the first polarizing beam splitter. As such, in embodiments, the first polarizing beam splitter may be configured to direct one of the first linear polarization comprising first device light and the second linear polarization comprising first device light to the dichroic beam splitter. Moreover, in embodiments, the first polarizing beam splitter may (also) be configured to direct at least part of the second device light to the dichroic beam splitter.
In embodiments, the dichroic beam splitter may be configured to transmit the first device light received by the dichroic beam splitter and/or the second device light received by the dichroic beam splitter to the luminescent material, and reflect the luminescent material light received by the dichroic beam splitter (optionally via part of the optics) to the light exit. Alternatively, in embodiments, the dichroic beam splitter may be configured to reflect the first device light received by the dichroic beam splitter and/or the second device light received by the dichroic beam splitter, and transmit the luminescent material light received by the dichroic beam splitter (optionally via part of the optics) to the light exit. As such, in embodiments, the dichroic beam splitter may also function as a beam combiner (e.g. configured to combine (along a same optical path) the luminescent material light with the diffused device light). Hence, in embodiments, part of the optics (especially in some embodiments the dichroic beam splitter) may be configured to combine at least part of the luminescent material light and at least part of the diffused device light into a same optical path. Herein, the phrase “to combine X and Y into a same optical path” and similar phrases may refer to the respective beams of light being provided such, that their respective optical axes may be substantially parallel and/or may coincide. The term “optical axis” may especially be defined as an imaginary line that defines the path along which light propagates through a system. Especially, the optical axis may coincide with the direction of the light with the highest radiant flux. Therefore, in embodiments, the dichroic beam splitter may comprise one or more of a (flat or tile-shaped) dichroic mirror (e.g. a flat plat or tile comprising a dichroic coating), a dichroic cube (e.g. a cube comprising a diagonally oriented internal plane comprising a dichroic coating), and a dichroic sphere (e.g. a sphere comprising a cross-sectional internal plane comprising a dichroic coating). For example, in some embodiments, the luminescent material light and the diffused device light may be provided to the dichroic beam splitter from orthogonal directions, and the dichroic beam splitter may comprise a dichroic mirror configured to combine the (yellow) luminescent material light and the (blue) diffused device light into the same optical path. Hence, in embodiments, the optics may further comprise a (first) dichroic beam splitter configured between the first polarizing beam splitter and the luminescent material; wherein the first polarizing beam splitter may be configured to direct one of the first linear polarization comprising first device light and the second linear polarization comprising first device light to the dichroic beam splitter, wherein the dichroic beam splitter may be configured to: (a) transmit the first device light received by the dichroic beam splitter and/or the second device light received by the dichroic beam splitter to the luminescent material, and reflect the luminescent material light received by the dichroic beam splitter (optionally via part of the optics) to the light exit, or (b) reflect the first device light received by the dichroic beam splitter and/or the second device light received by the dichroic beam splitter, and transmit the luminescent material light received by the dichroic beam splitter (optionally via part of the optics) to the light exit.
The optics may further, in embodiments, (also) comprise a (polarizing) beam splitter arrangement. Especially, in embodiments, the beam splitter arrangement may be configured between (relative to the propagation of light through the system) the first polarizing beam splitter and the diffuser arrangement. Hence, in embodiments where the diffuser arrangement comprises the above described X/4 waveplate, the beam splitter arrangement may be configured between (relative to the propagation of light through the system) the first polarizing beam splitter and the X/4 waveplate, such that the X/4 waveplate may be configured (directly) upstream of the diffuser.
In embodiments, the beam splitter arrangement may comprise at least a polarizing beam splitter. Further, in embodiments, the beam splitter arrangement may thus be configured in a light receiving relationship with the first polarizing beam splitter (optionally via one or more optics). Moreover, in embodiments, the beam splitter arrangement may be configured to transmit (first) device light received by the beam splitter arrangement and comprising the first linear polarization and to reflect (first) device light received by the beam splitter arrangement and comprising the second linear polarization. Alternatively, in embodiments, the beam splitter arrangement may be configured to reflect (first) device light received by the beam splitter arrangement and comprising the first linear polarization and to transmit (first) device light received by the beam splitter arrangement and comprising the second linear polarization. For example, in embodiments, the beam splitter arrangement may be configured to reflect s-polarized (first) device light and to transmit p-polarized (first) device light(, and/or vice versa). Note that, in embodiments, the beam splitter arrangement may also function as a beam combiner (e.g. configured to combine (along a same optical path) the luminescent material light and the diffused device light). Hence, in embodiments, the optics may further comprise a (polarizing) beam splitter arrangement, configured between the first polarizing beam splitter and the diffuser arrangement, wherein the beam splitter arrangement may be configured (i) to transmit device light received by the beam splitter arrangement and comprising the first linear polarization and to reflect device light received by the beam splitter arrangement and comprising the second linear polarization, or (ii) to reflect device light received by the beam splitter arrangement and comprising the first linear polarization and to transmit device light received by the beam splitter arrangement and comprising the second linear polarization.
Further, in embodiments, the beam splitter arrangement may be configured to combine the luminescent material light and the diffused device light. In embodiments, the luminescent material arrangement and the diffuser arrangement may be configured to provide the luminescent material light and the diffused device light, respectively, to the beam splitter arrangement (optionally via one or more optics). As such, in embodiments, the luminescent material light and the diffused device light may especially be provided to the beam splitter arrangement in directions orthogonal to each other. Hence, in embodiments, the beam splitter arrangement may be configured to combine the luminescent material light and the diffused device light such that the luminescent material light and the diffused device light may propagate along the same optical path to the light exit. Therefore, in embodiments, the beam splitter arrangement may comprise a polarizing beam splitter with an additional spectral requirement such that at least (a substantial) part of a spectral power of the luminescent material light received by the beam splitter arrangement may be transmitted. In other words, the beam splitter arrangement may be configured, such that at least (a substantial) part of a spectral power of the luminescent material light received by the beam splitter arrangement may be transmitted. Especially in embodiments, (the spectral requirement of the polarizing beam splitter of) the beam splitter arrangement may be selected such that at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95%, including 100% of the spectral power of the luminescent material light received by the beam splitter arrangement may be transmitted. Furthermore, in such embodiments, the beam splitter arrangement may be configured to transmit first device light (comprising one of the first linear polarization and the second linear polarization) received by the beam splitter arrangement and/or reflect diffused device light (comprising the other one of the first linear polarization and the second linear polarization) received by the beam splitter arrangement.
Alternatively, in embodiments, the beam splitter arrangement may comprise a polarizing beam splitter with an additional spectral requirement such that at least (a substantial) part of a spectral power of the luminescent material light received by the beam splitter arrangement may be reflected. In other words, the beam splitter arrangement may be configured, such that at least (a substantial) part of a spectral power of the luminescent material light received by the beam splitter arrangement may be reflected. Especially in embodiments, (the spectral requirement of the polarizing beam splitter of) the beam splitter arrangement may be selected such that at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95%, including 100% of the spectral power of the luminescent material light received by the beam splitter arrangement may be reflected.
In embodiments, such a spectral requirement as described above may e.g. be achieved by providing an optical layer (or coating), especially a dichroically active layer, to (the polarizing beam splitter of) the beam splitter arrangement. Further, in embodiments, one or more such optical layers, such as an arrangement of such optical layers, may be provided to (the polarizing beam splitter of) the beam splitter arrangement.
Furthermore, in such embodiments, the beam splitter arrangement may be configured to reflect first device light (comprising one of the first linear polarization and the second linear polarization) received by the beam splitter arrangement and/or transmit diffused device light (comprising the other one of the first linear polarization and the second linear polarization) received by the beam splitter arrangement. Hence, in embodiments, the beam splitter arrangement may comprise a polarizing beam splitter with an additional spectral requirement such that (i) at least 80% of a spectral power of the luminescent material light received by the beam splitter arrangement may be transmitted, and such that the beam splitter arrangement may (also) be configured to transmit first device light received by the beam splitter arrangement and to reflect diffused device light received by the beam splitter arrangement, or (ii) at least 80% of a spectral power of the luminescent material light received by the beam splitter arrangement may be reflected, and such that the beam splitter arrangement may (also) be configured to reflect first device light received by the beam splitter arrangement and to transmit diffused device light received by the beam splitter arrangement.
Hence, in embodiments, the beam splitter arrangement may be configured between (relative to the propagation of light through the system) the first polarizing beam splitter and the (reflective mode) diffuser. In some embodiments, the beam splitter arrangement may be configured to transmit first device light (comprising one of the first linear polarization and the second polarization) and to reflect diffused device light (comprising the other one of the first linear polarization and the second polarization). Would, in such embodiments, the first polarizing beam splitter be configured to provide (especially transmit) p-polarized first device light towards the beam splitter arrangement, in embodiments, the beam splitter arrangement may be capable of transmitting said p-polarized first device light to the diffuser arrangement. However, would, in such embodiments, the first polarizing beam splitter be configured to provide (especially reflect) s-polarized first device light towards the beam splitter arrangement, in embodiments, an additional polarization converter may be required between (relative to the propagation of light through the system) the first polarizing beam splitter and the beam splitter arrangement. The polarization converter may, in embodiments, especially comprise a birefringent rotator. Especially, in embodiments, the polarization converter may comprise a X/2 waveplate. In embodiments, the polarization converter may be configured to convert first device light comprising the first linear polarization (e.g. p or s polarization) into first device light comprising the second linear polarization (e.g. s or p polarization). Additionally or alternatively, in embodiments, the polarization converter may be configured to convert first device light comprising the second linear polarization (e.g. s or p polarization) into first device light comprising the first linear polarization (e.g. p or s polarization). The polarization of the first device light may thus impact the optical path the first device light may follow through the light generating system. Therefore, in embodiments, the light generating system may comprise the polarization control system, such that the polarization of the first device light may be controlled. In embodiments, the polarization control system may comprise a birefringent rotator configured downstream of the first light generating device and upstream of the first polarizing beam splitter. As such, in embodiments, the birefringent rotator may be configured to receive the first device light emitted by the first light generating device and may be configured to adjust (or control) the polarization of the first device light, such that first device light having a predetermined (linear) polarization may be provided to the first polarizing beam splitter. Especially, in embodiments, the polarization control system may be configured to control rotation of the birefringent rotator, such that the polarization of the first device light reaching the first polarizing beam splitter may be adjusted. The birefringent rotator may therefore, in embodiments, comprise a X/2 waveplate. Here, in embodiments, the wavelength X may especially refer to a representative wavelength of the incoming beam of first device light, with which, upon rotation about the optical axis (of the birefringent rotator), the polarization of the incoming (linearly polarized) beam of first device light can be rotated by any angle. Hence, in embodiments, with a X/2 waveplate configured in an optical path between the first light generating device and the first polarizing beam splitter, a linearly polarized beam of first device light may be adjusted such that a beam of first device light comprising any ratio of p/(s+p) and s/(s+p) may be provided to the first polarizing beam splitter. In such embodiments, p may refer to the p-polarized fraction and s may refer to the s-polarized fraction relative to a splitting (transmitting vs reflecting) plane of the first polarizing beam splitter.
Additionally or alternatively, in embodiments, the polarization control system may comprise an actuator. In embodiments, the actuator may be configured to (mechanically) rotate the first light generating device (and optionally the second light generating device). As such, in embodiments, the actuator may change the polarization of (a beam of) the first device light provided to the first polarizing beam splitter. The polarization control system may, in embodiments, be configured to control the actuator. Especially, in embodiments, the polarization control system may be configured to control the actuator such that the polarization of the first device light reaching the first polarizing beam splitter may be adjusted. Furthermore, in some embodiments, the polarization control system may comprise both the birefringent rotator and the actuator. In such embodiments, the actuator may (also) be configured to control the birefringent rotator. However, in alternative such embodiments, the polarization control system may comprise a separate actuator for the birefringent rotator. Hence, in embodiments, the polarization control system may comprise one or more of (A) a birefringent rotator configured downstream of the first light generating device and upstream of the first polarizing beam splitter, wherein the polarization control system may be configured to control rotation of the birefringent rotator (such that the polarization of the first device light reaching the first polarizing beam splitter may be adjusted); and wherein the birefringent rotator may comprise a X/2 waveplate; and (B) an actuator configured to (mechanically) rotate the first light generating device (and optionally the second light generating device), wherein the polarization control system may be configured to control the actuator (such that the polarization of the first device light reaching the first polarizing beam splitter may be adjusted).
Conversely to the above described, in some embodiments, the luminescent material and the diffuser may both be configured in the transmissive mode. Here below, such embodiments where the luminescent material and the diffuser are both configured in the transmissive mode are described in further detail. Such embodiments may be beneficial as no additional optical elements (such as waveplates) are necessary to separate the undiffused device light from the diffused device light. An additional benefit thereof may be that the polarization of the device light reaching the diffuser arrangement may be irrelevant of its function.
In embodiments with both the luminescent material and the diffuser configured in the transmissive mode different optics may be required to allow combination of the luminescent material light and the diffused device light along the same optical path to the light exit. Especially, in embodiments, the optics may comprise a dichroic beam splitter (see also above for suitable dichroics). In such embodiments, the dichroic beam splitter may in an operational mode be configured downstream (rather than upstream) of one or more of the luminescent material and the diffuser. Especially, in some embodiments, the dichroic beam splitter may in an operational mode be configured downstream of both the luminescent material and the diffuser. In some embodiments, the dichroic beam splitter may be configured to transmit the diffused device light (received by the dichroic beam splitter) and reflect the luminescent material light (received by the dichroic beam splitter). Alternatively, in embodiments, the dichroic beam splitter may be configured to reflect the diffused device light (received by the dichroic beam splitter) and transmit the luminescent material light (received by the dichroic beam splitter). Hence, in embodiments, the optics may further comprise a dichroic beam splitter configured downstream of both the luminescent material and the diffuser, wherein the dichroic beam splitter may be configured to: (a) transmit the diffused device light and reflect the luminescent material light, or (b) reflect the diffused device light and transmit the luminescent material light.
In some embodiments, (such as e.g. when the diffuser may be configured in the transmissive mode,) the first device light provided to the diffuser may have essentially any polarization, i.e., there may be essentially no limitations to the polarization of the first device light provided to the diffuser. In such embodiments, the first polarizing beam splitter may thus even comprise a partially polarizing beam splitter. The partially polarizing beam splitter may, in embodiments, be configured to transmit first device light comprising the first linear polarization (received by the partially polarizing beam splitter) and part of the first device light comprising the second linear polarization (received by the partially polarizing beam splitter) and to reflect another part of the first device light comprising the second linear polarization (received by the partially polarizing beam splitter). Especially, in embodiments, the partially polarizing beam splitter may be configured to (re-)direct first device light comprising the second polarization such that at least 10%, like at least 20%, such as at least 30%, especially at least 40% may be reflected and at most 90%, like at most 80%, such as at most 70%, especially at most 60% may be transmitted. Additionally or alternatively, in embodiments, the partially polarizing beam splitter may be configured to reflect first device light comprising the first linear polarization (received by the partially polarizing beam splitter) and part of the first device light comprising the second linear polarization (received by the partially polarizing beam splitter) and to transmit another part of the first device light comprising the second linear polarization (received by the partially polarizing beam splitter). Especially, in embodiments, the partially polarizing beam splitter may be configured to (redirect first device light comprising the first polarization such that at least 10%, like at least 20%, such as at least 30%, especially at least 40% may be reflected and at most 90%, like at most 80%, such as at most 70%, especially at most 60% may be transmitted. For example, in embodiments, the partially polarizing beam splitter may be partially (e.g. 80%) reflective and partially (e.g. 20%) transmissive for s-polarized light, whereas it may be essentially fully transmissive for p-polarized light (or vice versa). Hence, in embodiments, the first polarizing beam splitter may comprise a partially polarizing beam splitter configured (ia) to transmit first device light comprising the first linear polarization and part of the first device light comprising the second linear polarization and (ib) to reflect another part of the first device light comprising the second linear polarization, or (iia) to reflect first device light comprising the first linear polarization and part of the first device light comprising the second linear polarization and (iib) to transmit another part of the first device light comprising the second linear polarization.
Furthermore, in some embodiments, (such as e.g. when the diffuser may be configured in the transmissive mode,) the partially polarizing beam splitter may (even) be configured to be partially reflective for both the first linear polarization and the second linear polarization. Hence, in such embodiments, the partially polarizing beam splitter may be configured (i) to transmit part (such as e.g. selected between 10-90%, like between 30-70%) of the first device light comprising the first linear polarization and part (such as e.g. selected between 10-90%, like between 30-70%) of the first device light comprising the second linear polarization, and (ii) to reflect another part (such as e.g. selected between 10-90%, like between 30-70%) of the first device light comprising the first linear polarization and another part (such as e.g. selected between 10-90%, like between 30-70%) of the first device light comprising the second linear polarization.
In embodiments where the diffuser is configured in the reflective mode and where the beam splitter arrangement is configured to transmit or reflect the first device light and reflect or transmit the diffused device light, partial polarization may be possible with some additional requirements. Especially, in such embodiments, the device light provided to the diffuser arrangement may be required to have only one of the first linear polarization and the second linear polarization. Therefore, in such embodiments, the first polarizing beam splitter may comprise a partially polarizing beam splitter configured to partially reflect p- polarized first device light while being essentially fully reflective for s-polarized first device light. Alternatively, in such embodiments, the first polarizing beam splitter may comprise a partially polarizing beam splitter configured to partially transmit s-polarized first device light while being essentially fully reflective for p-polarized first device light. Especially, in such embodiments, the light generating system may further comprise the above described polarization converter.
Furthermore, in embodiments, (especially when the diffuser and/or luminescent material may be configured in the transmissive mode) it may be desired to provide a safety mechanism, such that eye-safety may be ensured in case of failure (or decay) of one or more of the optical elements. For example, in embodiments, the safety mechanism may comprise a small-angle diffuse reflector configured to transmit undiffused (i.e. unsafe) device light (optionally to a beam dump) and to reflect diffused device light to the light exit optionally via one or more optics. However, alternative safety mechanisms may be possible as well, such as e.g. comprising one or more light sensors and/or a reflective polarizer.
Yet further, in embodiments, (especially when the luminescent material may be configured in the transmissive mode) it may be desired to configure the luminescent material onto (or into) a (translucent, e.g. ceramic) support comprising a low pass dichroic filter (e.g. configured as a layer or coating). In such embodiments, the low pass dichroic filter may be configured to transmit the (blue) device light and reflect the converted (yellow-green) luminescent material light. Alternatively, in embodiments, (especially when the luminescent material may be configured in the transmissive mode) it may be desired to configure the luminescent material (comprised e.g. by a ceramic plate) onto (or into) a metallic support comprising a hole configured to allow the (blue) device light to pass.
Conversely to the above described, in some embodiments, one of the luminescent material and the diffuser may be configured in the reflective mode and the other one of the luminescent material and the diffuser may be configured in a transmissive mode. Such embodiments may be beneficial as no additional optical elements (such as waveplates) are necessary to separate the undiffused device light from the diffused device light. An additional benefit thereof may be that the polarization of the device light reaching the diffuser arrangement may be irrelevant of its function. Further, in such embodiments, most elements of the previously described embodiments (where the luminescent material and diffuser are both configured in either the reflective of the transmissive mode) may be applied and/or combined here.
In embodiments, luminescent materials are selected from garnets and nitrides, especially doped with trivalent cerium or divalent europium, respectively. The term “nitride” may also refer to oxynitride or nitridosilicate, etc. Alternatively or additionally, the luminescent material(s) may be selected from silicates, especially doped with divalent europium.
Especially, the luminescent material is configured to convert at least part of the light source light into luminescent material light, wherein the luminescent material may comprise a (garnet) luminescent material of the type AsBsOn Ce, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc. Hence, the luminescent material light may e.g. be green light or yellow light (or in specific embodiments even orange (dependent upon the composition of the garnet and cerium concentration)). However, other embodiments are also possible, see below. In embodiments, 0.05-10% of the A elements comprise Ce, even more especially 0.05-5%, such as 0.1-5%. Especially, embodiments, 0.1-3% of the A elements comprise Ce, such as up to 2%, like selected from the range of 0.1-1.5%, such as at least above 0.5%.
Especially, a luminescent material comprises conversion material or is a conversion material. A luminescent material converts light from a light source, such as the light source light, into secondary light (here the luminescent material light). The luminescent material may comprise an organic group that converts the light, or a molecule that converts the light, or an inorganic group that converts the light, etc. Such groups (or molecule) may be indicated as converter element. The garnet type material as indicated above, comprises cerium (Ce) as converter element. Cerium comprising garnets are well known in the art.
Hence, in specific embodiments the luminescent material comprises a (first) luminescent material of the type AsEEOn Ce, wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc. Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Especially, B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al. Hence, especially suitable luminescent materials are cerium comprising garnet materials. Embodiments of garnets especially include A3B5O12 garnets, wherein A comprises at least yttrium or lutetium and wherein B comprises at least aluminum. Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B comprises aluminum (Al), however, B may also partly comprise gallium (Ga) and/or scandium (Sc) and/or indium (In), especially up to about 20% of Al, more especially up to about 10 % of Al (i.e. the B ions essentially consist of 90 or more mole % of Al and 10 or less mole % of one or more of Ga, Sc, and In); B may especially comprise up to about 10% gallium. In another variant, B and O may at least partly be replaced by Si and N. The element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and/or Tb are especially only present up to an amount of about 20% of A. In a specific embodiment, the garnet luminescent material comprises (Yi-xLux)3B50i2:Ce, wherein x is equal to or larger than 0 and equal to or smaller than 1. The term “:Ce”, indicates that part of the metal ions (i.e. in the garnets: part of the “A” ions) in the luminescent material is replaced by Ce. For instance, in the case of (Yi-xLux)3A150i2:Ce, part of Y and/or Lu is replaced by Ce. This is known to the person skilled in the art. Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the full correct formula could be (Yo.iLuo.89Ceo.oi)3A150i2. Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.
In embodiments, the luminescent material (thus) comprises A3B5O12 wherein in specific embodiments at maximum 10% of B-0 may be replaced by Si-N.
In specific embodiments the luminescent material comprises (YXI-X2- x3A’X2CeX3)3(Alyi-y2B’y2)5Oi2, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+y2=l, wherein 0<y2<0.2, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc. In embodiments, x3 is selected from the range of 0.001-0.1. In the present invention, especially xl>0, such as >0.2, like at least 0.8. Garnets with Y may provide suitable spectral power distributions.
In specific embodiments at maximum 10% of B-0 may be replaced by Si-N. Here, B in B-0 refers to one or more of Al, Ga, In and Sc (and O refers to oxygen); in specific embodiments B-0 may refer to Al-O. As indicated above, in specific embodiments x3 may be selected from the range of 0.001-0.04. Especially, such luminescent materials may have a suitable spectral distribution (see however below), have a relatively high efficiency, have a relatively high thermal stability, and allow a high CRI (optionally in combination with (the) light of other sources of light as described herein). Hence, in specific embodiments A may be selected from the group consisting of Lu and Gd. Alternatively or additionally, B may comprise Ga. Hence, in embodiments the luminescent material comprises (YXI-X2- x3(Lu,Gd)x2Cex3)3(Alyi-y2Gay2)5Oi2, wherein Lu and/or Gd may be available. Even more especially, x3 is selected from the range of 0.001-0.1, wherein 0<x2+x3<0.1, and wherein 0<y2<0.1. Further, in specific embodiments, at maximum 1% of B-0 may be replaced by Si- N. Here, the percentage refers to moles (as known in the art); see e.g. also EP3149108. In yet further specific embodiments, the luminescent material comprises (Yxi-xsCexs^ALOn, wherein xl+x3=l, and wherein 0<x3<0.2, such as 0.001-0.1.
In specific embodiments, the light generating device may only include luminescent materials selected from the type of cerium comprising garnets. In even further specific embodiments, the light generating device includes a single type of luminescent materials, such as (Yxi-x2-x3A’x2Cex3)3(Alyi-y2B’y2)5Oi2. Hence, in specific embodiments the light generating device comprises luminescent material, wherein at least 85 weight%, even more especially at least about 90 wt.%, such as yet even more especially at least about 95 weight % of the luminescent material comprises (Yxi-x2-x3A’x2Cex3)3(Alyi-y2B’y2)5Oi2. Here, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+y2=l, wherein 0<y2<0.2. Especially, x3 is selected from the range of 0.001-0.1. Note that in embodiments x2=0. Alternatively or additionally, in embodiments y2=0.
In specific embodiments, A may especially comprise at least Y, and B may especially comprise at least Al.
Alternatively or additionally, the luminescent material may comprise a luminescent material of the type AsSieNiuCe3 , wherein A comprises one or more of Y, La, Gd, Tb and Lu, such as in embodiments one or more of La and Y.
In specific embodiments, the luminescent material may comprise at least two different luminescent materials configured to provide luminescent material light having different spectral power distributions. As can be derived from the above, the term “different luminescent materials” may refer to luminescent materials that are different, or to two compositions, each including at least one luminescent material in common, but wherein the compositions differ. For instance, a primary luminescent material comprising luminescent materials A and B, and a secondary luminescent material comprising only A or only B, or comprising both A and B, but in a different weight ratio. Such primary luminescent material and secondary luminescent material may have different spectral power distributions of their respective luminescent material light.
The garnet type luminescent material may also be described with an alternative formula AsB^C’^On. Here, A may comprise one or more of (i) rare earth ions, such as one or more selected from Y3+, Lu3+, Gd3+, Tb3+, La3+, and (ii) divalent cations, such as Ca2+. Here, B may comprise one or more of (i) trivalent cations, such as one or more of Al3+, Ga3+, Sc3+, Sb3+, and In3+, and (ii) divalent cations, such as one or more of Mg2+ and Mn2+. Here, C may comprise one or more of (i) trivalent cations, such as one or more of Ga3+ and Al3+, (ii) divalent cations, such as Mn2+, and (iii) tetravalent cations, such as one or more of Si4+ and Ge4+. With such ions, the garnet crystal structure can be maintained. Other substitutions than mentioned may also be possible.
In embodiments, the luminescent material may alternatively or additionally comprise one or more of MS:Eu2+ and/or NESis Eu2 and/or MAlSiNs Eu2 and/or Ca2AlSi3O2Ns:Eu2+, etc., wherein M comprises one or more of Ba, Sr and Ca, especially in embodiments at least Sr. Hence, in embodiments, the luminescent material may comprise one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu and (Ba,Sr,Ca)2SisN8:Eu. In these compounds, europium (Eu) is substantially or only divalent, and replaces one or more of the indicated divalent cations. In general, Eu will not be present in amounts larger than 10% of the cation; its presence will especially be in the range of about 0.5 to 10%, more especially in the range of about 0.5 to 5% relative to the cation(s) it replaces. The term “:Eu”, indicates that part of the metal ions is replaced by Eu (in these examples by Eu2+). For instance, assuming 2% Eu in CaAlSi Eu, the correct formula could be (Cao.98Euo.o2)AlSiN3. Divalent europium will in general replace divalent cations, such as the above divalent alkaline earth cations, especially Ca, Sr or Ba. The material (Ba,Sr,Ca)S:Eu can also be indicated as MS:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca). Further, the material (Ba,Sr,Ca)2SisN8:Eu can also be indicated as NfcSis Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound Sr and/or Ba. In a further specific embodiment, M consists of Sr and/or Ba (not taking into account the presence of Eu), especially 50 to 100%, more especially 50 to 90% Ba and 50 to 0%, especially 50 to 10% Sr, such as Bai.sSro.sSis Eu (i.e. 75 % Ba; 25% Sr). Here, Eu is introduced and replaces at least part of M, i.e. one or more of Ba, Sr, and Ca). Likewise, the material (Ba,Sr,Ca)AlSiN3:Eu can also be indicated as MAlSi Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca). Eu in the above indicated luminescent materials is substantially or only in the divalent state, as is known to the person skilled in the art. Hence, such nitride luminescent materials may also be or comprise converter elements, here especially Eu2+.
Especially, the luminescent material may be an inorganic luminescent material, such as one or more of the above-described trivalent cerium or divalent europium comprising oxides, oxynitrides, or nitrides.
In embodiments, a red luminescent material may comprise one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu and (Ba,Sr,Ca)2SisN8:Eu. In these compounds, europium (Eu) is substantially or only divalent, and replaces one or more of the indicated divalent cations. In general, Eu will not be present in amounts larger than 10% of the cation; its presence will especially be in the range of about 0.5 to 10%, more especially in the range of about 0.5 to 5% relative to the cation(s) it replaces. The term “:Eu”, indicates that part of the metal ions is replaced by Eu (in these examples by Eu2+). For instance, assuming 2% Eu in CaAlSi Eu, the correct formula could be (Cao.98Euo.o2)AlSiN3. Divalent europium will in general replace divalent cations, such as the above divalent alkaline earth cations, especially Ca, Sr or Ba.
The material (Ba,Sr,Ca)S:Eu can also be indicated as MS:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca).
Further, the material (Ba,Sr,Ca)2SisN8:Eu can also be indicated as NfcSis Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound Sr and/or Ba. In a further specific embodiment, M consists of Sr and/or Ba (not taking into account the presence of Eu), especially 50 to 100%, more especially 50 to 90% Ba and 50 to 0%, especially 50 to 10% Sr, such as Bai.sSro.sSisNsEu (i.e. 75 % Ba; 25% Sr). Here, Eu is introduced and replaces at least part of M, i.e. one or more of Ba, Sr, and Ca).
Likewise, the material (Ba,Sr,Ca)AlSiN3:Eu can also be indicated as MAlSi Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca).
Eu in the above indicated luminescent materials is substantially or only in the divalent state, as is known to the person skilled in the art.
Blue luminescent materials may comprise YSO (Y2SiOs:Ce3+), or similar compounds, or BAM (BaMgAlioOi?:Eu2+), or similar compounds.
The term “luminescent material” herein especially relates to inorganic luminescent materials.
Alternatively or additionally, also other luminescent materials may be applied. For instance quantum dots and/or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc. etc.
Quantum dots are small crystals of semiconducting material generally having a width or diameter of only a few nanometers. When excited by incident light, a quantum dot emits light of a color determined by the size and material of the crystal. Light of a particular color can therefore be produced by adapting the size of the dots. Most known quantum dots with emission in the visible range are based on cadmium selenide (CdSe) with a shell such as cadmium sulfide (CdS) and zinc sulfide (ZnS). Cadmium free quantum dots such as indium phosphide (InP), and copper indium sulfide (CuInS?) and/or silver indium sulfide (AglnS?) can also be used. Quantum dots show very narrow emission band and thus they show saturated colors. Furthermore the emission color can easily be tuned by adapting the size of the quantum dots. Any type of quantum dot known in the art may be used in the present invention. However, it may be preferred for reasons of environmental safety and concern to use cadmium-free quantum dots or at least quantum dots having a very low cadmium content.
Instead of quantum dots or in addition to quantum dots, also other quantum confinement structures may be used. The term “quantum confinement structures” should, in the context of the present application, be understood as e.g. quantum wells, quantum dots, quantum rods, tripods, tetrapods, or nano-wires, etcetera.
Organic phosphors can be used as well. Examples of suitable organic phosphor materials are organic luminescent materials based on perylene derivatives, for example compounds sold under the name Lumogen® by BASF. Examples of suitable compounds include, but are not limited to, Lumogen® Red F305, Lumogen® Orange F240, Lumogen® Yellow F083, and Lumogen® F170.
Different luminescent materials may have different spectral power distributions of the respective luminescent material light. Alternatively or additionally, such different luminescent materials may especially have different color points (or dominant wavelengths).
As indicated above, other luminescent materials may also be possible. Hence, in specific embodiments the luminescent material is selected from the group of divalent europium containing nitrides, divalent europium containing oxynitrides, divalent europium containing silicates, cerium comprising garnets, and quantum structures. Quantum structures may e.g. comprise quantum dots or quantum rods (or other quantum type particles) (see above). Quantum structures may also comprise quantum wells. Quantum structures may also comprise photonic crystals.
The luminescent material may be comprised by a luminescent body. The luminescent body may be a layer, like a self-supporting layer. The luminescent body may also be a coating. The luminescent body may also comprise a luminescent coating on a support (especially a light transmissive support in the transmissive mode). Especially, the luminescent body may essentially be self-supporting. In embodiments, the luminescent material may be provided as luminescent body, such as a luminescent single crystal, a luminescent glass, or a luminescent ceramic body. Such body may be indicated as “converter body” or “luminescent body”. In embodiments, the luminescent body may be a luminescent single crystal or a luminescent ceramic body. For instance, in embodiments a cerium comprising garnet luminescent material may be provided as a luminescent single crystal or as a luminescent ceramic body. In other embodiments, the luminescent body may comprise a light transmissive body, wherein the luminescent material is embedded. For instance, the luminescent body may comprise a glass body, with luminescent material embedded therein. Or, the glass as such may be luminescent. In other embodiments, the luminescent body may comprise a polymeric body, with luminescent material embedded therein.
In specific embodiments, the luminescent body comprises a ceramic body comprising the luminescent material. Ceramic bodies are known in the art. Alternatively, the luminescent body comprises single crystal. In yet further specific embodiments, different types of luminescent bodies may be applied. Hence, the body may especially be selected from single crystalline bodies and ceramic bodies. The latter may be more easily made than the former, while they nevertheless may have good optical and/or thermal properties. Hence, in embodiments the body may be a ceramic body. However, in specific embodiments also a combination of single crystalline bodies and ceramic bodies may be applied. Especially, the luminescent body comprises a ceramic luminescent body. Hence, in specific embodiments the luminescent body is defined by a ceramic luminescent material. Therefore, in specific embodiments the luminescent material is a luminescent material that can be provided a ceramic luminescent body. Hence, the luminescent body may comprise a ceramic luminescent body.
Hence, in embodiments, the luminescent material arrangement may especially comprise a luminescent body comprising a luminescent material. Further, in embodiments, the (luminescent body comprising the) luminescent material may be configured in thermal contact with a thermally conductive material. Especially, in embodiments where the luminescent material is configured in the reflective mode, such thermal contact may be beneficial as the luminescent material may give rise to significant thermal dissipation. Similarly, in some embodiments, the diffuser may be configured in thermal contact with a thermally conductive material. An element may be considered in “thermal contact” with another element if it can exchange energy through the process of heat. Hence, the elements may be thermally coupled. In embodiments, thermal contact can be achieved by physical contact. In embodiments, thermal contact may be achieved via a thermally conductive material, such as a thermally conductive glue (or thermally conductive adhesive). Thermal contact may also be achieved between two elements when the two elements are arranged relative to each other at a distance of equal to or less than about 10 gm, though larger distances, such as up to 100 gm may be possible. The shorter the distance, the better the thermal contact. Especially, the distance is 10 pm or less, such as 5 pm or less, such as 1 gm or less. The distance may be the distanced between two respective surfaces of the respective elements. The distance may be an average distance. For instance, the two elements may be in physical contact at one or more, such as a plurality of positions, but at one or more, especially a plurality of other positions, the elements are not in physical contact. For instance, this may be the case when one or both elements have a rough surface. When two elements are in thermal contact, they may be in physical contact or may be configured at a short distance of each other, like at maximum 10 gm, such as at maximum 1 mm. When the two elements are configured at a distance from each other, an intermediate material may be configured in between, though in other embodiments, the distance between the two elements may filled with a gas, liquid, or may be vacuum. When an intermediate material is available, the larger the distance, the higher the thermal conductivity may be useful for thermal contact between the two elements. However, the smaller the distance, the lower the thermal conductivity of the intermediate material may be (of course, higher thermal conductive materials may also be used).
A thermally conductive material may especially have a thermal conductivity of at least about 20 W/(m*K), like at least about 30 W/(m*K), such as at least about 100 W/(m*K), like especially at least about 200 W/(m*K). In yet further specific embodiments, a thermally conductive material may especially have a thermal conductivity of at least about 10 W/(m*K). In embodiments, the thermally conductive material may comprise one or more of copper, aluminum, silver, gold, silicon carbide, aluminum nitride, boron nitride, aluminum silicon carbide, beryllium oxide, a silicon carbide composite, aluminum silicon carbide, a copper tungsten alloy, a copper molybdenum carbide, carbon, diamond, and graphite. Alternatively, or additionally, the thermally conductive material may comprise or consist of aluminum oxide. In embodiments, the thermally conductive material may be comprised by and/or configured in thermal contact with one or more of a heatsink, a heat spreader, and a two-phase cooling device.
Another solution for the thermal management of the luminescent material may be to, in embodiments, apply (or mount) the luminescent material onto a rotating element, such as e.g. a rotating (phosphor-)wheel (or disk) or a rotating rod (or cylinder). Such embodiments may enable thermal spreading and cooling without the need for e.g. active water cooling, and thereby enabling maximum possible irradiance values. Hence, in embodiments, the luminescent material may be configured onto a rotating element.
Further, in embodiments, the diffuser may be a static diffuser. Alternatively, in embodiments, the diffuser may be a dynamic diffuser, such as e.g. a rotating wheel or a rotating rod, with a reflective diffuser track. In contrast to a static diffuser, a dynamic diffuser may provide improved thermal behavior but may add bulk to the engine volume and rotating mass. Hence, in embodiments, the diffuser may (also) be configured onto a rotating element.
In some embodiments, the luminescent material and the diffuser may each be configured on a separate rotating element. Alternatively, in embodiments, the luminescent material and the diffuser may be configured on the same rotating element, such as e.g. combined as separate rings on a rotating wheel or a rotating rod.
Furthermore, in embodiments, the light generating system may comprise a second luminescent material (different from the above described (first) luminescent material). The second luminescent material may especially, in embodiments, be configured to convert at least part of the first device light into second luminescent material light. Especially, in embodiments, the second luminescent material may comprise one or more of Nao.sKo.sLisSiC^Eu2 , MSi2C>2N2: Eu2+, wherein M comprises one or more of Ba, Sr, and Ca, Sr[BeeON4]:Eu2+, and MAhC^Eu2 , wherein M comprises one or more of Ba, Sr, and Ca. Such embodiments may be beneficial as the second luminescent material may improve the color point adjustability of the light generating system. Especially, such embodiments may result in color point tunability along a line that is substantially parallel to the BBL in a targeted range of color temperatures.
In some embodiments, the second luminescent material may be configured together with, such as mixed with, the (first) luminescent material. Additionally or alternatively, in embodiments, the second luminescent material may be combined with the diffuser. For example, in embodiments, the light generating system may comprise a phosphor wheel comprising two concentric rings, wherein one ring may comprise the first luminescent material and the other ring may comprise a section comprising the diffuser and a section comprising the second luminescent material. The second luminescent material may thus, in embodiments, be configured integrated with the diffuser arrangement.
As indicated above, the light generating system may comprise optics. The term “optics” may especially refer to (one or more) optical elements. Hence, the terms “optics” and “optical elements” may refer to the same items. The optics may include one or more of (specular or surface textured) mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffractive elements, gratings, dichroics, selectively reflective and/or selectively transmissive optics, arrays of one or more of the afore-mentioned, etc.
Alternatively or additionally, the term “optics” may refer to a holographic element or a mixing rod. In embodiments, the optics may include one or more of beam expander optics and zoom lens optics. See further above for examples of optics. In embodiments, the optics may comprise an integrator, like a “Koehler integrator” (or “Kohler integrator”).
In specific embodiments, the optics may comprise one or more of a homogenizing optics, collimating optics, condensing optics, and reflecting optics. For example, in embodiments, the luminescent material light and the diffused laser light may be provided (e.g. by the dichroic beam splitter or the beam splitter arrangement as defined above) along the same optical path to the light exit, and the optics may comprise a beam homogenizer configured upstream of the light exit and configured to combine and homogenize the received light and to provide (homogenized white) system light to the light exit.
As indicated above, in embodiments, the light generating system may comprise laser banks. As beams of light emitted from such (multi-chip packages and/or) laser banks may comprise multiple narrow laser beams, each individual laser beam may represent a hot spot in the beam of device light. Focusing of such a beam of device light on e.g. a luminescent material may exceed the maximum tolerable local irradiance and result in damage to the luminescent material, or other materials present in the luminescent material arrangement. Therefore, in some embodiments, homogenizing optics may be applied and may especially be configured between (relative to the propagation of light through the system) the light generating devices (contributing to irradiation of the luminescent material) and collimating optics of the luminescent material, see also below. Similarly, in some embodiments, homogenizing optics may be applied and may especially be configured between (relative to the propagation of light through the system) the light generating devices (contributing to irradiation of the diffuser) and collimating optics of the diffuser, see also below. In embodiments, the homogenizing optics may e.g. comprise one or more of a transmissive volume diffuser, a transmissive surface diffuser, a reflective surface diffuser, a transmissive or reflective diffractive optical element, a transmissive holographic optical element, a single multi lens array, a double multi lens array such as a fly-eye lens array, or an integrating polygonal light pipe that may be either solid (with propagation in the integrator based on total internal reflection) or hollow (with propagation in the integrator based on specular reflection).
In embodiments, the condensing optics may comprise a first condensing optics configured (directly) upstream of the luminescent material and a second condensing optics configured (directly) upstream of the diffuser. Especially, in embodiments, the first condensing optics and the second condensing optics may each comprise at least one positive lens. In specific embodiments (such as e.g. when the luminescent material is configured in the reflective mode) the first condensing optics may comprise a first positive lens and a second smaller positive lens. In such embodiments, the smaller positive lens may especially be located between (relative to the propagation of light through the system) the first positive lens and the luminescent material or diffuser, respectively. Further, in embodiments, the optics may comprise a first collecting and collimating optics configured (directly) downstream of the luminescent material and a second collecting and collimating optics configured (directly) downstream of the diffuser. Especially, in embodiments, the first collecting and collimating optics and the second collecting and collimating optics may each comprise at least one positive lens, especially at least two positive lenses. In embodiments, the collimating optics and/or condensing optics, especially the lenses, may comprise glass materials, such as e.g. N-BK7, H-K51, B270, or fused silica (FS). The latter shows relatively low absorption and relatively low induced stress, but also has a relatively low refractive index. Therefore, if FS is used for all the lenses, in embodiments, the condensing optics for the reflective mode may preferably comprise three lenses.
As indicated above, the light generating system comprises a light generating device. A light generating device may especially be configured to generate device light. Especially, the light generating device may comprise a light source. The light source may especially configured to generate light source light. In embodiments, the device light may essentially consist of the device light. In other embodiments, the device light may essentially consist of converted light source light. In yet other embodiments, the device light may comprise (unconverted) light source light and converted light source light. Light source light may be converted with a luminescent material into luminescent material light and/or with an upconverter into upconverted light (see also below). The term “light generating device” may also refer to a plurality of light generating devices which may provide device light having essentially the same spectral power distributions. In specific embodiments, the term “light generating device” may also refer to a plurality of light generating devices which may provide device light having different spectral power distributions. The term “light source” may in principle relate to any light source known in the art. In a specific embodiment, the light source comprises a solid state LED light source (such as an LED or laser diode (or “diode laser”)). The term “light source” may also relate to a plurality of light sources, such as 2-2000 (solid state) LED light sources. Hence, the term LED may also refer to a plurality of LEDs.
Further, the term “light source” may in embodiments also refer to a so-called chips-on-board (COB) light source. The term “COB” especially refers to LED chips in the form of a semiconductor chip that is neither encased nor connected but directly mounted onto a substrate, such as a PCB. Hence, a plurality of light emitting semiconductor light source may be configured on the same substrate. In embodiments, a COB is a multi LED chip configured together as a single lighting module.
The term “light source” may also refer to a chip scaled package (CSP). A CSP may comprise a single solid state die with provided thereon a luminescent material comprising layer. The term “light source” may also refer to a midpower package. A midpower package may comprise one or more solid state die(s). The die(s) may be covered by a luminescent material comprising layer. The die dimensions may be equal to or smaller than 2 mm, such as in the range of e.g. 0.2-2 mm. Hence, in embodiments the light source comprises a solid state light source. Further, in specific embodiments, the light source comprises a chip scale packaged LED. Herein, the term “light source” may also especially refer to a small solid state light source, such as having a mini size or micro size. For instance, the light sources may comprise one or more of mini LEDs and micro LEDs. Especially, in embodiment the light sources comprise micro LEDs or “microLEDs” or “pLEDs”. Herein, the term mini size or mini LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm - 1 mm. Herein, the term p size or micro LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm and smaller.
The light source may have a light escape surface. For LED’s it may for instance be the LED die, or when a resin is applied to the LED die, the outer surface of the resin. In principle, it may also be the terminal end of a fiber. The term escape surface especially relates to that part of the light source, where the light actually leaves or escapes from the light source. The light source is configured to provide a beam of light. This beam of light (thus) escapes from the light exit surface of the light source. Likewise, a light generating device may comprise a light escape surface, such as an end window. Further, likewise a light generating system may comprise a light escape surface, such as an end window.
The term “light source” may refer to a semiconductor light-emitting device, such as a light emitting diode (LEDs), a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (VCSELs), an edge emitting laser, etc... The term “light source” may also refer to an organic light-emitting diode (OLED), such as a passive-matrix (PMOLED) or an active-matrix (AMOLED). In a specific embodiment, the light source comprises a solid-state light source (such as an LED or laser diode). In an embodiment, the light source comprises an LED (light emitting diode). The terms “light source” or “solid state light source” may also refer to a superluminescent diode (SLED).
The term “light source” may also relate to a plurality of (essentially identical (or different)) light sources, such as 2-2000 solid state light sources. In embodiments, the light source may comprise one or more micro-optical elements (array of micro lenses) downstream of a single solid-state light source, such as an LED, or downstream of a plurality of solid-state light sources (i.e. e.g. shared by multiple LEDs). In embodiments, the light source may comprise an LED with on-chip optics. In embodiments, the light source comprises pixelated single LEDs (with or without optics) (offering in embodiments on-chip beam steering).
In embodiments, the light source may be configured to provide primary radiation, which is used as such, such as e.g. a blue light source, like a blue LED, or a green light source, such as a green LED, and a red light source, such as a red LED. Such LEDs, which may not comprise a luminescent material (“phosphor”) may be indicated as direct color LEDs.
In other embodiments, however, the light source may be configured to provide primary radiation and part of the primary radiation is converted into secondary radiation. Secondary radiation may be based on conversion by a luminescent material. The secondary radiation may therefore also be indicated as luminescent material radiation. The luminescent material may in embodiments be comprised by the light source, such as an LED with a luminescent material layer or dome comprising luminescent material. Such LEDs may be indicated as phosphor converted LEDs or PC LEDs (phosphor converted LEDs). In other embodiments, the luminescent material may be configured at some distance (“remote”) from the light source, such as an LED with a luminescent material layer not in physical contact with a die of the LED. Hence, in specific embodiments the light source may be a light source that during operation emits at least light at wavelength selected from the range of 380-470 nm. However, other wavelengths may also be possible. This light may partially be used by the luminescent material.
In embodiments, the light generating device may comprise a luminescent material. In embodiments, the light generating device may comprise a PC LED. In other embodiments, the light generating device may comprise a direct LED (i.e. no phosphor). In embodiments, the light generating device may comprise a laser device, like a laser diode. In embodiments, the light generating device may comprise a superluminescent diode. Hence, in specific embodiments, the light source may be selected from the group of laser diodes and superluminescent diodes. In other embodiments, the light source may comprise an LED.
The light source may especially be configured to generate light source light having an optical axis (O), (a beam shape,) and a spectral power distribution. The light source light may in embodiments comprise one or more bands, e.g. having band widths as known for lasers.
The term “light source” may (thus) refer to a light generating element as such, like e.g. a solid state light source, or e.g. to a package of the light generating element, such as a solid state light source, and one or more of a luminescent material comprising element and (other) optics, like a lens, a collimator. A light converter element (“converter element” or “converter”) may comprise a luminescent material comprising element. For instance, a solid state light source as such, like a blue LED, is a light source. A combination of a solid state light source (as light generating element) and a light converter element, such as a blue LED and a light converter element, optically coupled to the solid state light source, may also be a light source (but may also be indicated as light generating device). Hence, a white LED is a light source (but may e.g. also be indicated as (white) light generating device).
The term “light source” herein may also refer to a light source comprising a solid state light source, such as an LED or a laser diode or a superluminescent diode.
The term “light source” may (thus) in embodiments also refer to a light source that is (also) based on conversion of light, such as a light source in combination with a luminescent converter material. Hence, the term “light source” may also refer to a combination of an LED with a luminescent material configured to convert at least part of the LED radiation, or to a combination of a (diode) laser with a luminescent material configured to convert at least part of the (diode) laser radiation.
In embodiments, the term “light source” may also refer to a combination of a light source, like an LED, and an optical filter, which may change the spectral power distribution of the light generated by the light source. Especially, the term “light generating device” may be used to address a light source and further (optical components), like an optical filter and/or a beam shaping element, etc.
The phrases “different light sources” or “a plurality of different light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from at least two different bins. Likewise, the phrases “identical light sources” or “a plurality of same light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from the same bin.
The term “solid state light source”, or “solid state material light source”, and similar terms, may especially refer to semiconductor light sources, such as a light emitting diode (LED), a diode laser, or a superluminescent diode.
The term “laser light source” especially refers to a laser. Such laser may especially be configured to generate laser light source light having one or more wavelengths in the UV, visible, or infrared, especially having a wavelength selected from the spectral wavelength range of 200-2000 nm, such as 300-1500 nm. The term “laser” especially refers to a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation.
Especially, in embodiments the term “laser” may refer to a solid-state laser. In specific embodiments, the terms “laser” or “laser light source”, or similar terms, refer to a laser diode (or diode laser).
Hence, in embodiments the light source comprises a laser light source. In embodiments, the terms “laser” or “solid state laser” or “solid state material laser” may refer to one or more of cerium doped lithium strontium (or calcium) aluminum fluoride (Ce:LiSAF, Ce:LiCAF), chromium doped chrysoberyl (alexandrite) laser, chromium ZnSe (CrZnSe) laser, divalent samarium doped calcium fluoride (Sm:CaF2) laser, Er:YAG laser, erbium doped and erbium-ytterbium codoped glass lasers, F-Center laser, holmium YAG (Ho: YAG) laser, Nd:YAG laser, NdCrYAG laser, neodymium doped yttrium calcium oxoborate Nd:YCa4O(BO3)3 or Nd:YCOB, neodymium doped yttrium orthovanadate (Nd:YVO4) laser, neodymium glass (Nd:glass) laser, neodymium YLF (Nd:YLF) solid-state laser, promethium 147 doped phosphate glass (147Pm3+:glass) solid-state laser, ruby laser (AhO3:Cr3+), thulium YAG (Tm:YAG) laser, titanium sapphire (Ti:sapphire; AhCLHi3 ) laser, trival ent uranium doped calcium fluoride (U:CaF2) solid-state laser, Ytterbium doped glass laser (rod, plate/chip, and fiber), Ytterbium YAG (Yb:YAG) laser, Yb2O3 (glass or ceramics) laser, etc. For instance, including second and third harmonic generation embodiments, the light source may comprise one or more of an F center laser, an yttrium orthovanadate (Nd:YVO4) laser, a promethium 147 doped phosphate glass (147Pm3+:glass), and a titanium sapphire (Ti:sapphire; AhO3:Ti3+) laser. For instance, considering second and third harmonic generation, such light sources may be used to generated blue light.
In embodiments, the terms “laser” or “solid state laser” or “solid state material laser” may refer to one or more of a semiconductor laser diodes, such as GaN, InGaN, AlGalnP, AlGaAs, InGaAsP, lead salt, vertical cavity surface emitting laser (VCSEL), quantum cascade laser, hybrid silicon laser, etc.
A laser may be combined with an upconverter in order to arrive at shorter (laser) wavelengths. For instance, with some (trivalent) rare earth ions upconversion may be obtained or with non-linear crystals upconversion can be obtained. Alternatively, a laser can be combined with a downconverter, such as a dye laser, to arrive at longer (laser) wavelengths.
As can be derived from the below, the term “laser light source” may also refer to a plurality of (different or identical) laser light sources. In specific embodiments, the term “laser light source” may refer to a plurality N of (identical) laser light sources. In embodiments, N=2, or more. In specific embodiments, N may be at least 5, such as especially at least 8. In this way, a higher brightness may be obtained. In embodiments, laser light sources may be arranged in a laser bank (see also above). The laser bank may in embodiments comprise heat sinking and/or optics e.g. a lens to collimate the laser light. Hence, in embodiments lasers in a laser bank (or “laser array bank”) may share the same optics.
The laser light source is configured to generate laser light source light (or “laser light”). The light source light may essentially consist of the laser light source light. The light source light may also comprise laser light source light of two or more (different or identical) laser light sources. For instance, the laser light source light of two or more (different or identical) laser light sources may be coupled into a light guide, to provide a single beam of light comprising the laser light source light of the two or more (different or identical) laser light sources. In specific embodiments, the light source light is thus especially collimated light source light. In yet further embodiments, the light source light is especially (collimated) laser light source light.
The laser light source light may in embodiments comprise one or more bands, having band widths as known for lasers. In specific embodiments, the band(s) may be relatively sharp line(s), such as having full width half maximum (FWHM) in the range of less than 20 nm at RT, such as equal to or less than 10 nm. Hence, the light source light has a spectral power distribution (intensity on an energy scale as function of the wavelength) which may comprise one or more (narrow) bands.
The beams (of light source light) may be focused or collimated beams of (laser) light source light. The term “focused” may especially refer to converging to a small spot. This small spot may be at the discrete converter region, or (slightly) upstream thereof or (slightly) downstream thereof. Especially, focusing and/or collimation may be such that the cross-sectional shape (perpendicular to the optical axis) of the beam at the discrete converter region (at the side face) is essentially not larger than the cross-section shape (perpendicular to the optical axis) of the discrete converter region (where the light source light irradiates the discrete converter region). Focusing may be executed with one or more optics, like (focusing) lenses. Especially, two lenses may be applied to focus the laser light source light. Collimation may be executed with one or more (other) optics, like collimation elements, such as lenses and/or parabolic mirrors. In embodiments, the beam of (laser) light source light may be relatively highly collimated, such as in embodiments <2° (FWHM), more especially <1° (FWHM), most especially <0.5° (FWHM). Hence, <2° (FWHM) may be considered (highly) collimated light source light. Optics may be used to provide (high) collimation (see also above).
The term “solid state material laser”, and similar terms, may refer to a solid state laser like based on a crystalline or glass body doped with ions, like transition metal ions and/or lanthanide ions, to a fiber laser, to a photonic crystal laser, to a semiconductor laser, such as e.g. a vertical cavity surface-emitting laser (VCSEL), etc.
The term “solid state light source”, and similar terms, may especially refer to semiconductor light sources, such as a light emitting diode (LED), a laser diode, or a superluminescent diode.
Instead of the term “solid state light source” also the term “semiconductorbased light source” may be applied. Hence, the term “semiconductor-based light source” may e.g. refer to one or more of a light emitting diode (LED), a laser diode, and a superluminescent diode. Hence, the light generating device may comprise one or more of a light emitting diode (LED), a laser diode, and a superluminescent diode.
A light-emitting diode (LED) is especially a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor may recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) may be determined by the energy required for electrons to cross the band gap of the semiconductor.
A laser diode (or diode laser) may be a semiconductor device substantially similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction. This is known to a person skilled in the art.
Superluminescent diodes are known in the art. A superluminescent diode may be indicated as a semiconductor device which may be able to emit low-coherence light of a broad spectrum like an LED, while having a brightness in the order of a laser diode. Superluminescent diodes are e.g. described in US2020192017, incorporated herein by reference, or in “Edge Emitting Laser Diodes and Superluminescent Diodes”, Szymon Stanczyk, Anna Kafar, Dario Schiavon, Stephen Najda, Thomas Slight, Piotr Perlin, Book Editor(s): Fabrizio Roccaforte, Mike Leszczynski, First published: 03 August 2020 https://doi.org/10.1002/9783527825264.ch9 in chapter 9,3 superluminescent diodes. This book, and especially chapter 9.3, are herein incorporated by reference. Superluminescent diodes may combine the high power and brightness of laser diodes with the low coherence of conventional light-emitting diodes. The low (temporal) coherence of the source has advantages that the speckle is significantly reduced or not visible, and the spectral distribution of emission is much broader compared to laser diodes, which can be better suited for lighting applications. Hence, in embodiments, the solid state light source may comprise a superluminescent diode. For instance, in further specific embodiments, the solid state light source may comprise a GaN-based superluminescent diode, or an InGaN-based superluminescent diode, or an AlGaN-based superluminescent diode.
Especially, in embodiments the light generating device is configured to generate device light. In specific embodiments, the device light may be blue light. The terms “blue light” or “blue emission”, and similar terms, may especially relate to light having a wavelength in the range of about 440-490 nm (including some violet and cyan hues). However, intensity at shorter wavelengths may also be possible, such as within the wavelength range of 400-440 nm. In specific embodiments, the device light may have a centroid wavelength (Xci) selected from the 400-490 nm wavelength range, more especially from the 400-480 nm wavelength range. Especially, in embodiments the device light has a peak wavelength selected from the blue wavelength range.
The light generating system may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, digital projection, or LCD backlighting. The light generating system (or luminaire) may be part of or may be applied in e.g. optical communication systems or disinfection systems.
The terms “visible”, “visible light” or “visible emission” and similar terms refer to light having one or more wavelengths in the range of about 380-780 nm. Herein, UV may especially refer to a wavelength selected from the range of 190-380 nm, such as 200-380 nm. Herein, IR (infrared) may especially refer to radiation having a wavelength selected from the range of 780-3000 nm, such as 780-2000 nm, e.g. a wavelength up to about 1500 nm, like a wavelength of at least 900 nm, though in specific embodiments other wavelengths may also be possible.
The terms “light” and “radiation” are herein interchangeably used, unless clear from the context that the term “light” only refers to visible light. The terms “light” and “radiation” may thus refer to UV radiation, visible light, and IR radiation. In specific embodiments, especially for lighting applications, the terms “light” and “radiation” refer to (at least) visible light.
The terms “blue light” or “blue emission” especially relates to light having a wavelength in the range of about 440-495 nm (including some violet and cyan hues). The terms “green light” or “green emission” especially relate to light having a wavelength in the range of about 495-570 nm. The terms “yellow light” or “yellow emission” especially relate to light having a wavelength in the range of about 570-590 nm. The terms “orange light” or “orange emission” especially relate to light having a wavelength in the range of about 590- 620 nm. The terms “red light” or “red emission” especially relate to light having a wavelength in the range of about 620-780 nm. The phrase “light having one or more wavelengths in a wavelength range” and similar phrases may especially indicate that the indicated light (or radiation) has a spectral power distribution with at least intensity or intensities at these one or more wavelengths in the indicate wavelength range. For instance, a blue emitting solid state light source will have a spectral power distribution with intensities at one or more wavelengths in the 440-495 nm wavelength range.
The term “controlling” and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein “controlling” and similar terms may e.g. refer to imposing behavior to the element (determining the behavior or supervising the running of an element), etc., such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term “controlling” and similar terms may additionally include monitoring. Hence, the term “controlling” and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element. The controlling of the element can be done with a control system, which may also be indicated as “controller”. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. In embodiments, the control system and element may not be physically coupled. Control can be done via wired and/or wireless control. The term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems. A control system may comprise or may be functionally coupled to a user interface.
The control system may also be configured to receive and execute instructions from a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.
Hence, in embodiments the control system may (also) be configured to be controlled by an App on a remote device. In such embodiments the control system of the lighting system may be a slave control system or control in a slave mode. For instance, the lighting system may be identifiable with a code, especially a unique code for the respective lighting system. The control system of the lighting system may be configured to be controlled by an external control system which has access to the lighting system on the basis of knowledge (input by a user interface of with an optical sensor (e.g. QR code reader) of the (unique) code. The lighting system may also comprise means for communicating with other systems or devices, such as on the basis of Bluetooth, Thread, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.
The system, or apparatus, or device may execute an action in a “mode” or “operation mode” or “mode of operation” or “operational mode”. The term “operational mode may also be indicated as “controlling mode”. Likewise, in a method an action or stage, or step may be executed in a “mode” or “operation mode” or “mode of operation” or “operational mode”. This does not exclude that the system, or apparatus, or device may also be adapted for providing another controlling mode, or a plurality of other controlling modes. Likewise, this may not exclude that before executing the mode and/or after executing the mode one or more other modes may be executed.
However, in embodiments a control system may be available, that is adapted to provide at least the controlling mode. Would other modes be available, the choice of such modes may especially be executed via a user interface, though other options, like executing a mode in dependence of a sensor signal or a (time) scheme, may also be possible. The operation mode may in embodiments also refer to a system, or apparatus, or device, that can only operate in a single operation mode (i.e. “on”, without further tunability).
Hence, in embodiments, the control system may control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer. The term “timer” may refer to a clock and/or a predetermined time scheme.
In yet a further aspect, the invention also provides a lamp or a luminaire comprising the light generating system as defined herein. The luminaire may further comprise a housing, optical elements, louvres, etc. etc... The lamp or luminaire may further comprise a housing enclosing the light generating system. The lamp or luminaire may comprise a light window in the housing or a housing opening, through which the system light may escape from the housing. In yet a further aspect, the invention also provides a projection device comprising the light generating system as defined herein. Especially, a projection device or “projector” or “image projector” may be an optical device that projects an image (or moving images) onto a surface, such as e.g. a projection screen. The projection device may include one or more light generating systems such as described herein. Hence, in an aspect the invention also provides a lighting device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system as defined herein. The lighting device may comprise a housing or a carrier, configured to house or support, one or more elements of the light generating system. For instance, in embodiments the lighting device may comprise a housing or a carrier, configured to house or support one or more of the light generating devices, the luminescent material arrangement, the diffuser arrangement, and the optics. In embodiments, the invention may thus comprise an optical wireless communication device comprising the light generating system. In such embodiments, one or more of the first light generating device and the second light generating device may especially comprise a high frequency laser and/or may be amplitude modulated. In specific embodiments, especially the first light generating device may comprise a high frequency laser and/or may be amplitude modulated. Such embodiments may be beneficial as in such embodiments the light generating device providing the fraction of (blue laser) diffused device light to the reflective diffuser is modulated, which is generally faster in their temporal response (i.e., in their decay rate) than luminescent material.
Instead of the terms “lighting device” or “lighting system”, and similar terms, also the terms “light generating device” or “light generating system”, (and similar terms), may be applied. A lighting device or a lighting system may be configured to generate device light (or “lighting device light”) or system light (“or lighting system light”). As indicated above, the terms light and radiation may interchangeably be used.
The lighting device may comprise a light source. The device light may in embodiments comprise one or more of light source light and converted light source light (such as luminescent material light).
The lighting system may comprise a light source. The system light may in embodiments comprise one or more of light source light and converted light source light (such as luminescent material light).
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:
Figs. 1-4 schematically depict some embodiments of the light generating system.
Fig. 5 schematically depicts some applications of the light generating system in lighting devices. The schematic drawings are not necessarily to scale.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Fig. 1 schematically depicts an embodiment of the light generating system 1000 of the invention comprising light generating devices 100, a luminescent material arrangement 2000, a diffuser arrangement 7000, optics 500, a polarization control system 600, a light exit 1090, and a control system 300. Especially, the light generating devices 100 may comprise (i) a first light generating device 110 configured to generate first device light 111, and (ii) a second light generating device 120 configured to generate second device light 121. In embodiments, the first light generating device 110 and the second light generating device 120 (each) may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode. Especially, in some embodiments, the first light generating device 110 may comprise a first laser bank comprising a plurality of first lasers 10. Similarly, in some embodiments, the second light generating device 120 may comprise a second laser bank comprising a plurality of second lasers 20.
Further, in embodiments, the luminescent material arrangement 2000 may comprise a luminescent material 200 configured to convert at least part of first device light 111 and/or second device light 121 received by the luminescent material 200 into luminescent material light 201. Especially, in embodiments, the luminescent material 200 may at least comprise a first luminescent material 210 of the type AsBsOn Ce. Especially, in embodiments, A may comprise one or more of Y, La, Gd, Tb and Lu. Moreover, in embodiments, B may comprise one or more of Al, Ga, In and Sc.
Conversely, in embodiments, the diffuser arrangement 7000 may comprise a diffuser 700 configured to diffuse first device light 111 received by the diffuser 700 into diffused device light 701.
Hence, in embodiments, the first device light 111 and the second device light 121 may propagate from the light generating devices 100 to one or more of the luminescent material arrangement 2000 and the diffuser arrangement 7000. Especially, the light generating system 1000 may be configured such that the first device light 111 and the second device light 121 received by the first polarizing beam splitter 510 may comprise polarized light. Therefore, in embodiments, the optics 500 may comprise a first polarizing beam splitter 510 configured (a) downstream of the first light generating device 110 and second light generating device 120 and (b) upstream of both the luminescent material arrangement 2000 and the diffuser arrangement 7000. Especially, in embodiments, the first polarizing beam splitter 510 may be configured to transmit (device) light received by the first polarizing beam splitter 510 and comprising a first linear polarization and to reflect (device) light received by the first polarizing beam splitter 510 and comprising a second linear polarization, different from the first linear polarization. Alternatively, in embodiments, the first polarizing beam splitter 510 may be configured to reflect (device) light received by the first polarizing beam splitter 510 and comprising the first linear polarization and to transmit (device) light received by the first polarizing beam splitter 510 and comprising the second linear polarization.
In embodiments, the polarization control system 600 may especially be configured to control a polarization of the first device light 111 reaching the first polarizing beam splitter 510. Especially, the polarization control system 600 may be configured to control a ratio of first device light comprising the first linear polarization I l la relative to first device light comprising the second linear polarization 11 lb.
Further, in embodiments, the optics 500 and the second light generating device 120 may be configured such that at least 90% of the second device light 121 received by the first polarizing beam splitter 510 may be directed towards the luminescent material arrangement 2000. Furthermore, in some embodiments, the polarization control system 600 may be configured to control a polarization of the first device light 111 reaching the first polarizing beam splitter 510, such that (selected from the range of) 50-98% of the first device light 111 received by the first polarizing beam splitter 510 may be directed to the luminescent material arrangement 2000.
Additionally or alternatively, in embodiments, in a first operational mode of the light generating system 1000 in dependence of the polarization at least part of the first device light 111 received by the first polarizing beam splitter 510 may be directed towards the luminescent material arrangement 2000 and at least another part of the first device light 111 received by the first polarizing beam splitter 510 may be directed towards the diffuser arrangement 7000.
In embodiments, the optics 500 may further be configured such that the luminescent material light 201 may propagate via part of the optics 500 (such as e.g. via dichroic beam splitter 520 as depicted in Fig. 1 A or via both the dichroic beam splitter 520 and a beam splitter arrangement 515 as depicted in Figs. 2 and 3) to the light exit 1090. Additionally or alternatively, in embodiments, the optics 500 may further be configured such that the diffused device light 701 may propagate via part of the optics 500 (such as e.g. via both the beam splitter arrangement 515 and the dichroic beam splitter 520 as depicted in Fig. 1A or via the beam splitter arrangement 515 as depicted in Figs. 2 and 3) to the light exit 1090. Hence, in embodiments, the light generating system 1000 may be configured to provide in the first operational mode of the light generating system 1000 at the light exit 1090 system light 1001 comprising one or more of at least part of the luminescent material light 201 and at least part of the diffused device light 701.
Furthermore, in embodiments, the control system 300 may be configured to control a spectral power distribution of the system light 1001 by controlling one or more of the polarization control system 600 and the light generating devices 100.
As depicted in Figs. 1 A, 2, and 3, in embodiments, the luminescent material 200 and the diffuser 700 may be both configured in the reflective mode. In such embodiments, the diffuser 700 may especially comprise a polarization maintaining diffuser. Moreover, in embodiments, the diffuser arrangement 7000 may further comprise a X/4 waveplate 710 configured between the first polarizing beam splitter 510 and the diffuser 700. In embodiments, the first polarizing beam splitter 510 may be configured to direct first device light 111 received by the first polarizing beam splitter 510 and comprising the first linear polarization (1 I la) (not depicted) or the second linear polarization (11 lb) (as depicted) (optionally via optics 500) to the X/4 waveplate 710. In embodiments, the X/4 waveplate 710 may be configured to convert first device light 111 received by the X/4 waveplate 710 and comprising a linear polarization into first device light 111 comprising a (first) circular polarization (e.g., as depicted I l la). Additionally, in embodiments, the X/4 waveplate 710 may be configured to convert diffused device light 701 received by the X/4 waveplate (via the diffuser 700) and comprising a (second) circular polarization (in the figure indicated with 701’) into diffused device light 701 comprising a linear polarization (in the figure indicated with 701”). Note that references 701’ and 701” are only indicated in Fig. 1A, but may be analogously applied to the Figs. 2 and 3.
Moreover, in such embodiments, the optics 500 may further comprise a (first) dichroic beam splitter 520 configured between the first polarizing beam splitter 510 and the luminescent material 200. In embodiments, the first polarizing beam splitter 510 may be configured to direct (at least) one of the first linear polarization comprising first device light 11 la (as depicted in Fig. 3) and the second linear polarization comprising first device light 111b (as depicted in Figs. 1 A, and 2) to the (first) dichroic beam splitter 520. The (first) dichroic beam splitter 520 may then, in embodiments, be configured to transmit the first device light 111 received by the (first) dichroic beam splitter 520 and/or the second device light 121 received by the (first) dichroic beam splitter 520 to the luminescent material 200, and to reflect the luminescent material light 201 received by the (first) dichroic beam splitter 520 (optionally via part of the optics 500) to the light exit 1090. Alternatively, in embodiments (not depicted), the first dichroic beam splitter 520 may be configured to reflect the first device light 111 received by the (first) dichroic beam splitter 520 and/or the second device light 121 received by the (first) dichroic beam splitter 520, and to transmit the luminescent material light 201 received by the (first) dichroic beam splitter 520 (optionally via part of the optics 500) to the light exit 1090.
Moreover, in embodiments, the optics 500 may further comprise a (polarizing) beam splitter arrangement 515, configured between the first polarizing beam splitter 510 and the diffuser arrangement 7000. Especially, in embodiments, the beam splitter arrangement 515 may be configured to transmit device light 111 (e.g., as depicted I l la) received by the beam splitter arrangement 515 and comprising the first linear polarization and to reflect device light 111 received by the beam splitter arrangement 515 and comprising the second linear polarization (such as e.g. as depicted diffused device light 701). Alternatively, in embodiments (not depicted), the beam splitter arrangement 515 may be configured to reflect device light 111 received by the beam splitter arrangement 515 and comprising the first linear polarization and to transmit device light 111 received by the beam splitter arrangement 515 and comprising the second linear polarization. In such alternative embodiments the beam splitter arrangement 515 and the diffuser arrangement 7000 may especially be flipped 90° relative to the rest of the light generating system 1000.
In further embodiments, the polarization control system 600 may comprise a birefringent rotator 610 configured downstream of the first light generating device 110 and upstream of the first polarizing beam splitter 510. Especially, in embodiments, the polarization control system 600 may be configured to control rotation of the birefringent rotator 610, such that the polarization of the first device light 111 reaching the first polarizing beam splitter 510 may be adjusted. Further, in embodiments, the birefringent rotator 610 may comprise a X/2 waveplate. Additionally or alternatively, in embodiments, the polarization control system 600 may comprise an actuator 630 configured to (mechanically) rotate the first light generating device 100 (and optionally the second light generating device 120). Especially, in embodiments, the polarization control system 600 may be configured to control the actuator 630, such that the polarization of the first device light 111 reaching the first polarizing beam splitter 510 may be adjusted. In some embodiments, the actuator 630 may also be configured to (mechanically) rotate the birefringent rotator 610. However, in other embodiments, the polarization control system 600 may comprise a separate actuator (not depicted) configured to rotate the birefringent rotator 610.
The optics may further comprise a plurality of additional components. Here especially reference 530 may refer to homogenizing optics, reference 540 may refer to collimating (and/or condensing) optics, and reference 550 may refer to reflecting optics (such as e.g. a specular reflector).
Here below, working principles relating to Fig. 1 A are described in further detail. Note that this figure represents an example of the light generating system 1000, and hence different elements and working principles of the invention may be applied as well.
As depicted in Fig. 1 A, a second (blue laser) light generating device 120 may be fully used for luminescent conversion at the luminescent material 200. Conversely here a first (blue laser) light generating device 110 may be partly used for luminescent conversion and partly used to contribute as blue (diffused device) light spectral component to the output white system light 1001. Especially, the second device light 121 may propagate from the second light generating device 120 to the first polarizing beam splitter 510. The first polarizing beam splitter 510 may here be configured to substantially transmit the second device light 121, such that the second device light 121 may propagate to the dichroic beam splitter 520. The dichroic beam splitter may here be configured to substantially transmit the second device light 121 such that the second device light 121 may propagate to the luminescent material 200. Conversely, the first device light 111 may propagate from the first light generating device 110 to the birefringent rotator 610. The birefringent rotator may provide a ratio of first linear polarization comprising first device light 11 la to second linear polarization comprising first device light 11 lb. At the first polarizing beam splitter the second polarization comprising first device light 111b may be reflected to the dichroic beam splitter 520, whereas the first linear polarization comprising first device light I l la may be transmitted to a reflecting optics 550. The second polarization comprising first device light 111b may be transmitted towards the luminescent material 200 by the dichroic beam splitter 520. Note here that the functionality of the dichroic beam splitter 520 is (substantially) independent of the polarization of (blue) device light 111,121 that is incident upon it. At the luminescent material 200 the second device light 121 and the second polarization comprising first device light 111b may be converted into (yellow-green) luminescent material light 201. The luminescent material light 201 may propagate from the luminescent material 200 back to the dichroic beam splitter 520, where it may be reflected to the light exit 1090. Meanwhile, the first linear polarization comprising first device light I l la may be reflected by the reflecting optics 550 to the beam splitter arrangement 515. The beam splitter arrangement 515 may be configured to transmit the first linear polarization comprising first device light 11 la to the X/4 waveplate 710. At the X/4 waveplate 710 the first linear polarization comprising first device light I l la may be converted into (first) circular polarization comprising first device light. The (first) circular polarization comprising first device light may then propagate to the diffuser 700 where it may be diffused to (second) circular polarization comprising diffused device light 701,701’. The (second) circular polarization comprising diffused device light 701,701’ may propagate back to the X/4 waveplate 710 where it may be converted into second linear polarization comprising diffused device light 701,701”. The (second linear polarization comprising) diffused device light 701(,701”) may then be reflected to the dichroic beam splitter 520 by the beam splitter arrangement 515. At the dichroic beam splitter 520 the (second linear polarization comprising) diffused device light 701(,701”) may be transmitted to the light exit 1090. Hence at the light exit system light 1001 comprising at least part of the luminescent material light 201 and at least part of the diffused device light 701 may be provided.
Conversely to Fig. 1 A, in Fig. 2 the luminescent material light 201 and the diffused device light 701 may be combined by and may propagate to the light exit 1090 via the beam splitter arrangement 515 rather than the dichroic beam splitter 520. Therefore, in embodiments as depicted here, the beam splitter arrangement 515 may not only comprise a polarizing beam splitter, but may have an additional spectral requirement such that at least 80% of a spectral power of the luminescent material light 201 received by the beam splitter arrangement 515 may be transmitted, and such that the beam splitter arrangement 515 may be (also) configured to transmit first device light 111 (e.g. as depicted I l la) received by the beam splitter arrangement 515 and reflect diffused device light 701 received by the beam splitter arrangement 515. Alternatively, in embodiments (not depicted), the beam splitter arrangement 515 may have an additional spectral requirement such that at least 80% of a spectral power of the luminescent material light 201 received by the beam splitter arrangement 515 may be reflected, and such that the beam splitter arrangement 515 may be (also) configured to reflect first device light 111 received by the beam splitter arrangement 515 and transmit diffused device light 701 received by the beam splitter arrangement 515.
In Fig. 3, the light generating system 1000 may be similar to that depicted in Fig. 2, however, here the second linear polarization comprising first device light 111b may be directed to the diffuser arrangement 7000 rather than the first linear polarization comprising first device light I l la. For example, in embodiments, the second linear polarization comprising first device light 111b may be an s-polarized fraction of the first device light 111 and may thus be split off by the first polarizing beam splitter 510 towards the diffuser 700. In such embodiments, however, the polarization of the first device light 111 split off towards the diffuser 700 has to be changed from s- to p-polarization before arriving at the integrated beam splitter arrangement 515. To make that possible, an additional X/2 waveplate may be inserted in the optical path of the s-polarized fraction of first device light 111 that was split off by first polarizing beam splitter 510 towards the diffuser 700. Hence, in such embodiments, an additional polarization converter 620 may be required. Especially, in embodiments, the polarization converter 620 may be configured between the first polarizing beam splitter 510 and the (polarizing) beam splitter arrangement 515. Especially, in embodiments, the polarization converter 620 may comprise a X/2 waveplate. Further, in embodiments (not depicted), the polarization converter 620 may be configured to convert first device light 111 comprising the first linear polarization into first device light 111 comprising the second linear polarization. Alternatively, in embodiments as depicted here, the polarization converter 620 may be configured to convert the first device light 111 comprising the second linear polarization (e.g. as depicted 11 lb) into first device light 111 comprising the first linear polarization (e.g. as depicted I l la). In other words, the polarization converter 620 may be configured to convert the first linear polarization comprising first device light I l la into second polarization comprising first device light 111b and vice versa.
Further, as depicted here, in embodiments, the luminescent material 200 (and optionally the diffuser 710) may be configured onto a rotating element 750, such as e.g. a phosphor wheel or a rotating rod. Additionally or alternatively, in embodiments, the , the luminescent material 200 (and optionally the diffuser 710) may be configured in thermal contact with a thermally conductive material.
In further embodiments, such as depicted in Figs. IB and 4, the luminescent material 200 and the diffuser 710 may be both configured in the transmissive mode.
As depicted in Fig. IB, in embodiments, the optics 500 may further comprise a dichroic beam splitter 520 configured downstream of both the luminescent material 200 and the diffuser 700. Especially, in embodiments, the dichroic beam splitter 520 may be configured to transmit the diffused device light 701 and reflect the luminescent material light 201 (not depicted). Alternatively, in embodiments as depicted here, the dichroic beam splitter 520 may be configured to reflect the diffused device light 701 and transmit the luminescent material light 201.
Fig. 4 may schematically depict a light generating system 1000 similar to the one depicted in Fig. IB, i.e., where the luminescent material 200 and the diffuser 700 are both configured in the transmissive mode. However, as depicted here, the first polarizing beam splitter 510 may comprise a partially polarizing beam splitter. In embodiments, the partially polarizing beam splitter may be configured (i) to transmit first device light 111 comprising the first linear polarization and part of the first device light 111 comprising the second linear polarization and (ii) to reflect another part of the first device light 111 comprising the second linear polarization. In other words, as depicted here the partially polarizing beam splitter may be configured (i) to transmit first linear polarization comprising first device light I l la and part of the second linear polarization comprising first device light 111b and (ii) to reflect another part of the second linear polarization comprising first device light 11 lb. Alternatively, in embodiments, (not depicted here), the partially polarizing beam splitter may be configured (i) to reflect first device light 111 comprising the first linear polarization and part of the first device light 111 comprising the second linear polarization and (ii) to transmit another part of the first device light 111 comprising the second linear polarization.
Further, in yet other embodiments, one of the luminescent material 200 and the diffuser 700 may be configured in the reflective mode and the other one of the luminescent material 200 and the diffuser 700 may be configured in a transmissive mode. Such embodiments are not depicted here, but may apply a combination of the features as described above.
Fig. 5 schematically depicts an embodiment of a luminaire 2 comprising the light generating system 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system 300 comprised by or functionally coupled to the light generating system 1000. Fig. 5 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a projector device or projector system, which may be used to project images, such as at a wall, which may also comprise the light generating system 1000. Hence, Fig. 5 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a luminaire 2, a projector device 3, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system 1000 as described herein. In embodiments, such lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, or an optical wireless communication device. Lighting device light escaping from the lighting device 1200 is indicated with reference 1201. Lighting device light 1201 may essentially consist of system light 1001, and may in specific embodiments thus be system light 1001. Reference 1300 refers to a space, such as a room.
The term “plurality” refers to two or more.
The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%.
The term “comprise” also includes embodiments wherein the term
“comprises” means “consists of’. The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of' but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species".
Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.
The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.
In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.
Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.
The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.
The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. In yet a further aspect, the invention (thus) provides a software product, which, when running on a computer is capable of bringing about (one or more embodiments of) the method as described herein. The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.
The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.
The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

CLAIMS:
1. A light generating system (1000) comprising light generating devices (100), a luminescent material arrangement (2000), a diffuser arrangement (7000), optics (500), a polarization control system (600), a light exit (1090), and a control system (300); wherein: the light generating devices (100) comprise (i) a first light generating device (110) configured to generate first device light (111), and (ii) a second light generating device
(120) configured to generate second device light (121); wherein the first light generating device (110) and the second light generating device (120) comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode; the luminescent material arrangement (2000) comprises a luminescent material (200) configured to convert at least part of first device light (111) and/or second device light
(121) received by the luminescent material (200) into luminescent material light (201); the diffuser arrangement (7000) comprises a diffuser (700) configured to diffuse first device light (111) received by the diffuser (700) into diffused device light (701); the optics (500) comprise a first polarizing beam splitter (510) configured (a) downstream of the first light generating device (110) and second light generating device (120) and (b) upstream of both the luminescent material arrangement (2000) and the diffuser arrangement (7000); wherein the light generating system (1000) is configured such that the first device light (111) and the second device light (121) received by the first polarizing beam splitter (510) comprise polarized light; the first polarizing beam splitter (510) is configured (ia) to transmit light received by the first polarizing beam splitter (510) and comprising a first linear polarization and (ib) to reflect light received by the first polarizing beam splitter (510) and comprising a second linear polarization, different from the first linear polarization, or (iia) to reflect light received by the first polarizing beam splitter (510) and comprising the first linear polarization and (iib) to transmit light received by the first polarizing beam splitter (510) and comprising the second linear polarization; the polarization control system (600) is configured to control a polarization of the first device light (111) reaching the first polarizing beam splitter (510); the optics (500) and the second light generating device (120) are configured such that (i) at least 90% of the second device light (121) received by the first polarizing beam splitter (510) is directed towards the luminescent material arrangement (2000), and (ii) in a first operational mode of the light generating system (1000) in dependence of the polarization at least part of the first device light (111) received by the first polarizing beam splitter (510) is directed towards the luminescent material arrangement (2000) and at least another part of the first device light (111) received by the first polarizing beam splitter (510) is directed towards the diffuser arrangement (7000); the optics (500) are further configured such that the luminescent material light (201) propagates via part of the optics (500) to the light exit (1090) and such that the diffused device light (701) propagates via part of the optics (500) to the light exit (1090); the light generating system (1000) is configured to provide in the first operational mode of the light generating system (1000) at the light exit (1090) system light (1001) comprising one or more of at least part of the luminescent material light (201) and at least part of the diffused device light (701); the control system (300) is configured to control a spectral power distribution of the system light (1001) by controlling one or more of the polarization control system (600) and the light generating devices (100); wherein the first device light (111) has a first peak wavelength (Xpi) selected from the wavelength range of 440-480 nm, wherein the second device light (121) has a second peak wavelength (Xp2) selected from the wavelength range of 440-480 nm; and wherein in an operational mode of the light generating system (1000) the system light (1001) is white light having a correlated color temperature selected from the range of 2700-10000 K and a color rendering index of at least 65.
2. The light generating system (1000) according to any one of the preceding claims, wherein the luminescent material (200) and the diffuser (700) are both configured in the reflective mode; wherein the diffuser (700) comprises a polarization maintaining diffuser, and wherein the diffuser arrangement (7000) further comprises a X/4 waveplate (710) configured between the first polarizing beam splitter (510) and the diffuser (700), wherein the first polarizing beam splitter (510) is configured to direct first device light (111) received by the first polarizing beam splitter (510) and comprising the first linear polarization or the second linear polarization to the X/4 waveplate (710), wherein the X/4 waveplate (710) is configured to (i) convert first device light (111) received by the X/4 waveplate (710) and comprising a linear polarization into first device light (111) comprising a circular polarization, and (ii) convert diffused device light (701) received by the X/4 waveplate and comprising a circular polarization into diffused device light (701) comprising a linear polarization.
3. The light generating system (1000) according to any one of the preceding claims, wherein the optics (500) further comprise a dichroic beam splitter (520) configured between the first polarizing beam splitter (510) and the luminescent material (200); wherein the first polarizing beam splitter (510) is configured to direct one of the first linear polarization comprising first device light (1 I la) and the second linear polarization comprising first device light (11 lb) to the dichroic beam splitter (520), wherein the dichroic beam splitter (520) is configured to: (a) transmit the first device light (111) received by the dichroic beam splitter (520) and/or the second device light (121) received by the dichroic beam splitter (520) to the luminescent material (200), and reflect the luminescent material light (201) received by the dichroic beam splitter (520) to the light exit (1090), or (b) reflect the first device light (111) received by the dichroic beam splitter (520) and/or the second device light (121) received by the dichroic beam splitter (520), and transmit the luminescent material light (201) received by the dichroic beam splitter (520) to the light exit (1090).
4. The light generating system (1000) according to any one of the preceding claims, wherein the optics (500) further comprises a beam splitter arrangement (515), configured between the first polarizing beam splitter (510) and the diffuser arrangement (7000), wherein the beam splitter arrangement (515) is configured (i) to transmit device light (111) received by the beam splitter arrangement (515) and comprising the first linear polarization and to reflect device light (111) received by the beam splitter arrangement (515) and comprising the second linear polarization, or (ii) to reflect device light (111) received by the beam splitter arrangement (515) and comprising the first linear polarization and to transmit device light (111) received by the beam splitter arrangement (515) and comprising the second linear polarization.
5. The light generating system (1000) according to claim 4, wherein the beam splitter arrangement (515) comprises a polarizing beam splitter, wherein the beam splitter arrangement (515) is further configured, such that (i) at least 80% of a spectral power of the luminescent material light (201) received by the beam splitter arrangement (515) is transmitted, and such that the beam splitter arrangement (515) is configured to transmit first device light (111) received by the beam splitter arrangement (515) and to reflect diffused device light (701) received by the beam splitter arrangement (515), or (ii) at least 80% of a spectral power of the luminescent material light (201) received by the beam splitter arrangement (515) is reflected, and such that the beam splitter arrangement (515) is configured to reflect first device light (111) received by the beam splitter arrangement (515) and to transmit diffused device light (701) received by the beam splitter arrangement (515).
6. The light generating system (1000) according to any one of the preceding claims, wherein the polarization control system (600) comprises one or more of a birefringent rotator (610) configured downstream of the first light generating device (110) and upstream of the first polarizing beam splitter (510), wherein the polarization control system (600) is configured to control rotation of the birefringent rotator (610); and wherein the birefringent rotator (610) comprises a X/2 waveplate; an actuator (630) configured to rotate the first light generating device (100), wherein the polarization control system (600) is configured to control the actuator (630).
7. The light generating system (1000) according to claim 1, wherein the luminescent material (200) and the diffuser (710) are both configured in the transmissive mode.
8. The light generating system (1000) according to claim 6, wherein the optics (500) further comprise a dichroic beam splitter (520) configured downstream of both the luminescent material (200) and the diffuser (700), wherein the dichroic beam splitter (520) is configured to: (a) transmit the diffused device light (701) and reflect the luminescent material light (201), or (b) reflect the diffused device light (701) and transmit the luminescent material light (201).
9. The light generating system (1000) according to claim 1, wherein one of the luminescent material (200) and the diffuser (700) is configured in the reflective mode and the other one of the luminescent material (200) and the diffuser (700) is configured in a transmissive mode.
10. The light generating system (1000) according to any one of the preceding claims, wherein the polarization control system (600) is configured to control a polarization of the first device light (111) reaching the first polarizing beam splitter (510), such that 50- 98% of the first device light (111) received by the first polarizing beam splitter (510) is directed to the luminescent material arrangement (2000).
11. The light generating system (1000) according to any one of the preceding claims, wherein the first light generating device (110) comprises a first laser bank comprising a plurality of first lasers (10), and wherein the second light generating device (120) comprises a second laser bank comprising a plurality of second lasers (20).
12. The light generating system (1000) according to any one of the preceding claims, wherein the system light (1001) is white light having a correlated color temperature selected from the range of 6500-8000 K and a color rendering index of at least 70.
13. The light generating system (1000) according to any one of the preceding claims, wherein the first polarizing beam splitter (510) comprises a partially polarizing beam splitter configured (ia) to transmit first device light (111) comprising the first linear polarization and part of the first device light (111) comprising the second linear polarization and (ib) to reflect another part of the first device light (111) comprising the second linear polarization, or (iia) to reflect first device light (111) comprising the first linear polarization and part of the first device light (111) comprising the second linear polarization and (iib) to transmit another part of the first device light (111) comprising the second linear polarization.
14. The light generating system (1000) according to any one of the preceding claims, wherein the luminescent material (200) is configured (i) in thermal contact with a thermally conductive material and/or (ii) onto a rotating element; and wherein the luminescent material (200) at least comprises a luminescent material of the type AsBsOn Ce, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc.
15. A lighting device (1200) selected from the group of a lamp (1), a luminaire (2), and an optical wireless communication device, comprising the light generating system (1000) according to any one of the preceding claims.
PCT/EP2025/050235 2024-01-11 2025-01-07 Tunable cct maximum output laser-phosphor engine with two laser banks Pending WO2025149476A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP24151366.2 2024-01-11
EP24151366 2024-01-11

Publications (1)

Publication Number Publication Date
WO2025149476A1 true WO2025149476A1 (en) 2025-07-17

Family

ID=89619196

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2025/050235 Pending WO2025149476A1 (en) 2024-01-11 2025-01-07 Tunable cct maximum output laser-phosphor engine with two laser banks

Country Status (1)

Country Link
WO (1) WO2025149476A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3149108A2 (en) 2014-09-11 2017-04-05 Philips Lighting Holding B.V. Pc-led module with enhanced white rendering and conversion efficiency
US20200192017A1 (en) 2018-12-13 2020-06-18 Exalos Ag Superluminescent Diode Module
US20200333699A1 (en) 2019-04-18 2020-10-22 Canon Kabushiki Kaisha Light source apparatus and image projection apparatus
US20220091493A1 (en) 2019-08-05 2022-03-24 Panasonic Intellectual Property Management Co., Ltd. Light source device and projection-type display apparatus
WO2022143318A1 (en) 2020-12-31 2022-07-07 万民 Light emitting device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3149108A2 (en) 2014-09-11 2017-04-05 Philips Lighting Holding B.V. Pc-led module with enhanced white rendering and conversion efficiency
US20200192017A1 (en) 2018-12-13 2020-06-18 Exalos Ag Superluminescent Diode Module
US20200333699A1 (en) 2019-04-18 2020-10-22 Canon Kabushiki Kaisha Light source apparatus and image projection apparatus
US20220091493A1 (en) 2019-08-05 2022-03-24 Panasonic Intellectual Property Management Co., Ltd. Light source device and projection-type display apparatus
WO2022143318A1 (en) 2020-12-31 2022-07-07 万民 Light emitting device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
SZYMON STANCZYKANNA KAFARDARIO SCHIAVONSTEPHEN NAJDATHOMAS SLIGHTPIOTR PERLIN: "Edge Emitting Laser Diodes and Superluminescent Diodes", 3 August 2020

Similar Documents

Publication Publication Date Title
US11767966B2 (en) High intensity light source with high CRI and R9
CN116324265A (en) Laser phosphor light source with improved brightness and thermal management
WO2025008197A1 (en) High flux laser phosphor engine with partial polarization beam splitter and tunable color point
WO2024160723A1 (en) Tunable beam comprising laser phosphor engine
WO2024184100A1 (en) Laser-phosphor engine with partial polarizing beam splitter and tunable color point
US12493194B2 (en) High brightness light source providing light using twin phosphors
WO2025149476A1 (en) Tunable cct maximum output laser-phosphor engine with two laser banks
WO2025146308A1 (en) Laser-phosphor light engine for stage-lighting using a diffuser in the transmissive mode
EP4476477B1 (en) Heatsink comprising a closed-loop slit for pumping a cylindrical phosphor body
JP7727879B1 (en) High-intensity laser phosphor lighting with CCT control
WO2025021470A1 (en) High brightness white light source comprising a blue laser bank and a blue-red laser bank
WO2025186130A1 (en) Constant power tunable cct laser-phosphor source comprising three laser banks
WO2025209863A1 (en) Tunable laser-phosphor source with increased gamut area
WO2025261881A1 (en) Laser-phosphor engine architecture comprising a geometric beam combiner
WO2025068067A1 (en) Laser combination configuration for obtaining white stage lighting without differential aging
WO2025012199A1 (en) Laser-phosphor light source using phosphor in a transmission and a reflection mode
WO2025209970A1 (en) Laser-phosphor engine with multiple blue sources and fractional use for diffused blue
WO2024208634A1 (en) Laser-phosphor engine with rotating converter
WO2025223872A1 (en) Tunable constant power dual laser-phosphor engine with single laser wavelength
EP4649259A1 (en) Laser-phosphor based stage lighting engine with a highly efficient polarization maintaining diffuser configuration
WO2025153402A1 (en) Cct control using laser banks by splitting bank light in different portions for focusing laser light on phosphors and a diffuser
WO2024022844A1 (en) Laser-phosphor based fixture with polarization dependent beam shaping
WO2025228908A1 (en) Optimized retardation plates for producing eye-safe white laser light
WO2025186028A1 (en) Static phosphor and dynamic phosphor for producing high cri high-intensity light
WO2024231148A1 (en) Tunable laser phosphor engine with rotating optical wedge

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 25700317

Country of ref document: EP

Kind code of ref document: A1