WO2024160650A1

WO2024160650A1 - Laser light engine with rotating cylinder

Info

Publication number: WO2024160650A1
Application number: PCT/EP2024/051790
Authority: WO
Inventors: Daniël Anton BENOY; Hugo Johan Cornelissen; Rifat Ata Mustafa Hikmet; Christoph Gerard August HOELEN; Olexandr Valentynovych VDOVIN; Ties Van Bommel
Original assignee: Signify Holding BV
Current assignee: Signify Holding BV
Priority date: 2023-01-31
Filing date: 2024-01-25
Publication date: 2024-08-08
Anticipated expiration: 2025-07-31
Also published as: CN120604075A

Abstract

The invention provides a light generating system (1000) comprising a light generating device (100) and a light conversion system (2000), wherein: (A) the light generating device (100) is configured to generate device light (101); wherein the light generating device (100) comprises a solid state light source, wherein the solid state light source comprises one or more of a laser light source and a superluminescent diode; (B) the light conversion system (2000) comprises a light transmissive body (2100) and a luminescent material (200); (C) the light transmissive body (2100) is configured rotatable about a rotational axis (A); the light transmissive body (2100) comprises (i) an outer face (2110) configured at a distance (r1) from the rotational axis (A), and (ii) an inner part (2120) enclosed by the outer face (2110), wherein at least part of the inner part (2120) is light transmissive for the device light (101); (D) the luminescent material (200) is configured to convert at least part of the device light (101) received by the luminescent material (200) into luminescent material light (201); wherein the luminescent material (200) is configured at a part of the outer face (2110); and (E) the light generating system (1000) is configured such that during operation of the light generating system (1000) during at least part of the time at least part of the device light irradiates at least part of the luminescent material (200) from the inner part (2120).

Description

LASER LIGHT ENGINE WITH ROTATING CYLINDER

FIELD OF THE INVENTION

The invention relates to a light generating system. The invention further relates to a lighting device comprising such light generating system.

BACKGROUND OF THE INVENTION

Laser-phosphor based stage lighting engines 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.

US2022/290842A1 discloses a lighting device comprising a first laser light source configured to generate first light source light. The device further comprises a first yellow/green luminescent material, configured to convert at least part of the first light source light into first luminescent material light, and a second orange/red luminescent material configured to convert part of the first luminescent material light into second luminescent material light. The first laser light source, the first luminescent material, and the second luminescent material are configured such that first light source light can only reach the second luminescent material after scattering via the first luminescent material, and a first thermally conductive element is in thermal contact with the first and second luminescent material.

EP2677233B1 discloses a lamp with LEDs and a remote phosphor converter. The lamp comprises a heat-dissipating base with a radiation exit opening, and light-emitting diodes fixed over the periphery of the opening, with, arranged in series at a distance from said light-emitting diodes, a radiation converter in the form of a concave layer of phosphor material, the cavity of which is turned towards the light-emitting diodes and the exit opening. Light from the LEDs incident on the surface of the luminescent converter is partly converted to form white light as a result of the LED light passing through the converter and the converted light that mixes and exits through the layer of phosphor material.

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 laser light in combination to generate phosphor converted light. Thermal aspect at high powers, however, may be an issue. Other problems associated with such laser light sources may come with the desire to create compact high- power devices. Further, controllability of the spectral power distribution may also be an issue. 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 (“system”) comprising a light generating device and a light conversion system. Especially, the light generating device may be configured to generate device light. In specific embodiments, the light generating device may comprise a solid state light source. Yet, in embodiments the solid state light source comprises one or more of a laser light source and a superluminescent diode. In embodiments, the light conversion system may comprise a light transmissive body and a luminescent material. In specific embodiments, the light transmissive body may be configured rotatable about a rotational axis (or axis of rotation). In embodiments, the light transmissive body may comprise (i) an outer face, especially configured at a distance (rl) from the rotational axis (A), and (ii) an inner part enclosed by the outer face. In specific embodiments, at least part of the inner part is light transmissive for the device light. Especially, the luminescent material may be configured to convert at least part of the device light received by the luminescent material into luminescent material light. In embodiments, the luminescent material may be configured at a part of the outer face. In specific embodiments, the light generating system may be configured such that during operation of the light generating system during at least part of the time at least part of the device light may irradiate at least part of the luminescent material from the inner part. Therefore, in embodiments the invention provides a light generating system comprising a light generating device and a light conversion system, wherein: (A) the light generating device is configured to generate device light; wherein the light generating device comprises a solid state light source, wherein the solid state light source comprises one or more of a laser light source and a superluminescent diode; (B) the light conversion system comprises a light transmissive body and a luminescent material; (C) the light transmissive body is configured rotatable about a rotational axis (A); the light transmissive body comprises (i) an outer face configured at a distance (rl) from the rotational axis (A), and (ii) an inner part enclosed by the outer face, wherein at least part of the inner part is light transmissive for the device light; (D) the luminescent material is configured to convert at least part of the device light received by the luminescent material into luminescent material light; wherein the luminescent material is configured at a part of the outer face; and (E) the light generating system is configured such that during operation of the light generating system during at least part of the time at least part of the device light irradiates at least part of the luminescent material from the inner part.

With such system, the thermal load of the phosphor may be reduced and/or spread over different phosphor parts. Yet, the rotatable light transmissive body may allow good thermal management of the phosphor. Alternatively or additionally, with such system it may be possible to control the spectral power distribution of the (system) light escaping from the system. Further, the system may allow generating of light with a relatively high power. Yet, the system may allow a relatively compact system with relatively good thermal management. Further, with the system different phosphors may be spatially separated. This also allows the phosphors having different temperatures, by which the system performance may be improved. Hence, the invention provides amongst others a (tunable) laser light engine with rotating cylinder or rotating rod.

As indicated above, the invention provides amongst others a light generating system comprising a light generating device and a light conversion system. Here below, embodiments of the light generating device and of the light conversion system are described. Also specific embodiments of the light conversion system, optionally including optics, are described below.

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 light source 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 (other) 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. It may be a conventional (tungsten) light bulb, a low pressure mercury lamp, a high pressure mercury lamp, a fluorescent lamp, an LED (light emissive diode). 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 chip-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. Referring to conventional light sources such as light bulbs or fluorescent lamps, it may be an outer surface of a glass or a quartz envelope. 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 LED may also refer to a plurality of LEDs.

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 converted 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, 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 laser diode, 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; AhO3:Ti³⁺) 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 (trival ent) 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 dopes 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.

US2020192017 indicates for instance that “With current technology, a single SLED is capable of emitting over a bandwidth of, for example, at most 50-70 nm in the 800- 900 nm wavelength range with sufficient spectral flatness and sufficient output power. In the visible range used for display applications, i.e. in the 450-650 nm wavelength range, a single SLED is capable of emitting over bandwidth of at most 10-30 nm with current technology. Those emission bandwidths are too small for a display or projector application which requires red (640 nm), green (520 nm) and blue (450 nm), i.e. RGB, emission" . Further, superluminescent diodes are amongst others described, in “Edge Emitting Laser Diodes and Superluminescent Diodes”, Szymon Stanczyk, Anna Kafar, Dario Schiavon, Stephen Naj da, 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. Amongst others, it is indicated therein that the superluminescent diode (SLD) is an emitter, which combines the features of laser diodes and light-emitting diodes. SLD emitters utilize the stimulated emission, which means that these devices operate at current densities similar to those of laser diodes. The main difference between LDs and SLDs is that in the latter case, the device waveguide may be designed in a special way preventing the formation of a standing wave and lasing. Still, the presence of the waveguide ensures the emission of a high-quality light beam with high spatial coherence of the light, but the light is characterized by low time coherence at the same time” and “Currently, the most successful designs of nitride SLD are bent, curved, or tilted waveguide geometries as well as tilted facet geometries, whereas in all cases, the front end of the waveguide meets the device facet in an inclined way, as shown in Figure 9.10. The inclined waveguide suppresses the reflection of light from the facet to the waveguide by directing it outside to the lossy unpumped area of the device chip". Hence, an SLD may especially be a semiconductor light source, where the spontaneous emission light is amplified by stimulated emission in the active region of the device. Such emission is called “super luminescence”. Superluminescent diodes combine the high power and brightness of laser diodes with the low coherence of conventional lightemitting 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. Especially, with varying electrical current, the spectral power distribution of the superluminescent diode may vary. In this way the spectral power distribution can be controlled, see e.g. also Abdullah A. Alatawi, et al., Optics Express Vol. 26, Issue 20, pp. 26355-26364, https://doi.org/10.1364/QE.26.026355. Hence, a superluminescent diode may be indicated as a semiconductor device which may be able to emit low-coherence light of a broad spectrum like a LED, while having a brightness in the order of a laser diode. 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. Hence, especially the light generating device may be configured to generate device light. Further, in embodiments the light generating device comprises a solid state light source. Especially, in embodiments the solid state light source may comprise one or more of a laser light source and a superluminescent diode. Especially, the light generating device may comprise a diode laser. Hence, in specific embodiments the device light may comprise (especially be) laser light. In other specific embodiments, the device light may comprise (especially be) light from a superluminescent diode. In embodiments, the device light is 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). In specific embodiments, the blue light may have a centroid wavelength in the 440-490 nm range. Hence, in embodiments the device light may be blue laser light.

Further, the light generating system comprises a light conversion system. The light conversion system especially comprises a luminescent material (see further also below), which may be able to convert at least part of the device light into luminescent material light. In order to manage the thermal load, the light generating device, such as a laser, and the luminescent material may be configured in the system such that during operation of the system, the light generating device irradiates different parts of the luminescent material over time. To this end, a construction may be chosen wherein the luminescent material moves, like e.g. a rotating element comprising or provided with luminescent material.

Herein, the rotating element may especially not be a plate or disc, but a light transmissive body. The light transmissive body may in embodiments allow one or more of the following: (i) device light not absorbed by the luminescent material may propagate through the light transmissive body to another part of the same luminescent material, or to another luminescent material, and (ii) device light entering a hollow part of the light transmissive body may be redirected to the luminescent material with the aid of optics. In both cases, part of the device light may propagate from within the light transmissive body in the direction of external of the light transmissive body, thereby irradiating the luminescent material from internal. Hence, whether or not the light transmissive body is irradiated from external with the device light, at least part of this device light may irradiate at least part of the luminescent material from internal. Therefore, the rotation element may be light transmissive. Especially, the rotating element may be light transmissive for the device light, see further also below. Therefore, in embodiments the light conversion system may comprise a light transmissive body and a luminescent material. In embodiments, the light transmissive body may be configured rotatable about a rotational axis (A). Especially, the system may comprise an actuator configured to rotate the light transmissive body about the rotational axis (A). Rotational frequencies may e.g. be selected from the range of 40-300 Hz, such as at least about 50 Hz, though other rotational frequencies may also be possible. Hence, typically, the duration of irradiating the luminescent material is much shorter (> lOx, more commonly > 50x) than the duration of not irradiating the luminescent material.

The light transmissive body may in embodiments be cylindrically shaped, i.e. hollow, or have a rod-like shape, i.e. massive. Other shapes, however, are herein not excluded. For instance, whereas a cylinder may be hollow over its entire height, a rod-like shape with a cavity may also be an embodiments (which may be considered a hybrid embodiment of the cylinder and rod-like shape). In both indicated embodiments, the light transmissive body comprises (i) an outer face configured at a distance (rl). Especially, the distance may be constant over the height of the light transmissive body (defined parallel to the rotational axis). Especially, the distance (rl) is defined perpendicular to the rotational axis. Hence, especially the outer face may have essentially a single curvature, defined by the distance (rl) (though other embodiments are herein not excluded). The luminescent material may be provided on (part of the outer face). Alternatively or additionally, the outer face may comprise indentations, like an indented ring, wherein the luminescent material may be configured. The outer face may define an inner part. The inner part may thus especially comprise in embodiments a cylinder (i.e. hollow) or have a rod (i.e. massive). In both cases, the inner part may comprise a light transmissive material (see also below), such as in embodiments e.g. provided as cylinder of light transmissive material, or in other embodiments e.g. as light transmissive rod. Therefore, in embodiments the light transmissive body may comprise (i) an outer face configured at a distance (rl) from the rotational axis (A), and (ii) an inner part enclosed by the outer face, wherein at least part of the inner part may be light transmissive for the device light.

A hollow body may be lighter and may allow configuration of optics within the cavity. A massive body may be easier to handle and may facilitate a better thermal management. However, a hollow body may also be cooled by cooling fluid within the hollow part. For instance, a (cooling) gas (or a cooling liquid) may be guided through a hollow cylinder for cooling of especially the cylinder wall, and thereby the luminescent material. Yet, in embodiments spokes may be provided in a hollow body, to further facilitate thermal transport. Such spokes may be provided such that they stimulate the cooling air flow, like the blades of a fan that push air through a tube. Of course, they should not block the optical path.

Herein, the term “hollow light transmissive body” may especially refer to a light transmissive comprising a hollow part, such as a cavity. In embodiments, the hollow light transmissive body may especially be a light transmissive cylinder.

It is not necessary that the entire light transmissive body consists of light transmissive material, though the one or more portions that may comprise light transmissive material may especially facilitate that at least part of the device light may irradiate at least part of the luminescent material from internal. However, in specific embodiments the entire light transmissive body consists of light transmissive material; this may (especially) facilitate that at least part of the device light may irradiate at least part of the luminescent material from internal. Hence, in embodiments the light generating system is configured such that during operation of the light generating system during at least part of the time at least part of the device light irradiates at least part of the luminescent material from the inner part.

Further, as indicated above, especially the luminescent material may be configured to convert at least part of the device light received by the luminescent material into luminescent material light. Yet, as indicated above, the luminescent material is configured at a part of the outer face. The phrase “configured at a part of the outer face” may in embodiments indicate on the outer face and may in (other) embodiments indicate in a recessed part of the outer face.

Especially, the luminescent material may form at least part of a ring around the rotational axis (at (a part of) the outer face). In general, the height (defined parallel to the rotational axis) of the ring may be essentially constant over the perimeter. The entire ring may comprise the luminescent material, or one or more parts of the ring may comprise luminescent material. Hence, in embodiments the luminescent material may be configured in a semi-ring shape or in a ring-shape. Especially, however, the entire ring may comprise the luminescent material (especially having an essentially constant height)(and especially having an essentially constant thickness). This may allow a relatively easy operation. Therefore, in embodiments the light conversion system may have a circular cross-sectional shape (perpendicular to the rotational axis (A)) and the luminescent material may especially be configured in at least part of a ring-shaped arrangement at the outer face.

Here below, first some embodiments in relation to the luminescent material are described. The term “luminescent material” especially refers to a material that can convert first radiation, 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. 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 down-conversion. 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. Examples of possible luminescent materials are indicated below. Hence, the term “luminescent material” may in specific embodiments also refer to a luminescent material composition. 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 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. In specific embodiments the luminescent material comprises a luminescent material of the type AsBsOn 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 may comprise aluminum (Al); however, in addition to aluminum, B may also partly comprise gallium (Ga) and/or scandium (Sc) and/or indium (In), especially up to about 20% of B, more especially up to about 10 % of B (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-_xLu_x)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-_xLu_x)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 (Y_xiA’_X2Ce_X3)3(Al_yiB’y2)5Oi2, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+y2=l, wherein especially 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 (Y_xi(Lu,Gd)x2Cex3)3(AlyiGa_y2)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 (YxiCexs^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 (YxiA’x2Cex3)3(Al_yiB’_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 (YxiA’x2Ce_X3)3(Al_yiB’_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 embodiments, the luminescent material may alternatively or additionally comprise one or more of MS:Eu²⁺ and/or LSisNs 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 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.

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 nanowires, 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.

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 first luminescent material comprising luminescent materials A and B, and a second luminescent material comprising only A or only B, or comprising both A and B, but in a different weight ratio. Such first luminescent material and second luminescent material may have different spectral power distributions of their respective luminescent material light. Different luminescent materials may have luminescent material light differing in spectral power distribution. Especially, they may also differ in color point.

In specific embodiments, colors or color points of a first type of light and a second type of light may be different when the respective color points of the first type of light and the second type of light differ with at least 0.01 for u’ and/or with at least 0.01 for v’, even more especially at least 0.02 for u’ and/or with at least 0.02 for v’. In yet more specific embodiments, the respective color points of first type of light and the second type of light may differ with at least 0.03 for u’ and/or with at least 0.03 for v’. Here, u’ and v’ are color coordinates of the light in the CIE 1976 UCS (uniform chromaticity scale) diagram.

Spectral power distributions of different sources of light having centroid wavelengths differing least 10 nm, such as at least 20 nm, or even at least 30 nm may be considered different spectral power distributions, e.g. different colors. In general, the differences in centroid wavelengths will not be larger than about 400 nm, such as not more than 350 nm.

Hence, when there are two or more mutually differing luminescent material, the spectral power distributions of the (respective) luminescent material light may especially differ.

In yet other specific embodiments, two or more ring-shaped arrangements may comprise essentially the same luminescent materials, however, at least two of the two or more ring-shaped arrangements comprise the luminescent material with different thicknesses. This implies that irradiating the ring-shaped arrangement comprising a thicker luminescent material layer will lead to relatively more conversion, and thus more luminescent material light, and less remaining device light, whereas when irradiating the ring-shaped arrangement comprising a thinner luminescent material layer will lead to relatively less conversion, and thus relatively less luminescent material light, and relatively more remaining device light. In this way, the spectral power distribution of the system light may also be controlled. The thickness of the luminescent material is especially defined in a direction perpendicular to the rotational axis.

In yet other specific embodiments, of two or more ring-shaped arrangements one may comprise a luminescent material, and the other one may comprise a reflective material (reflective for the device light). This implies that irradiating the ring-shaped arrangement comprising the luminescent material layer may lead to conversion into luminescent material light, whereas when irradiating the ring-shaped arrangement comprising the reflective material, this may lead to no conversion, and thus essentially only (reflected) device light. In this way, the spectral power distribution of the system light may also be controlled. The reflective material may in embodiments be specular reflective. In other embodiments, it may be diffuse reflective.

In embodiments, device light may irradiate at least part of the luminescent material at the outer face (at a first position). Part of the device light irradiating the luminescent material may be absorbed by the luminescent material (and at least partly be converted into luminescent material light), another part may be transmitted by the luminescent material, may propagate through the light transmissive body, and reach a second position at the outer face luminescent material. Here, the device light at that second position of outer face may at least partly be absorbed by the luminescent material (and at least partly be converted into luminescent material light), and optionally part of the device light may also be transmitted. The luminescent material at that second part of outer face may thus be irradiated from internal of the light transmissive body. Therefore, in embodiments wherein the luminescent material is irradiated from external, the luminescent material may also be transmissive for the device light. Hence, in embodiments the luminescent material and its thickness may be chosen such that part of the device light received by the luminescent material is transmitted (and thus that part is not converted). For instance, in embodiments the luminescent material and its thickness may be chosen such that selected from the range of 20- 80% of (the spectral power of) the device light reached by the luminescent material is transmitted, and 80-20% of (the spectral power of) the device light reached by the luminescent material is absorbed, wherein the percentages may add up to 100% (not taking into account reflection at the luminescent material).

Therefore, in embodiments the luminescent material, configured in at least part of the ring-shaped arrangement at the outer face, is configured to absorb part of the device light received by the luminescent material; wherein the light generating system is configured such that device light irradiating the luminescent material in at least part of the ring-shaped arrangement from external of the light conversion system is at least partly transmitted by the luminescent material and the inner part and irradiates during operation of the light generating system during at least part of the time (also at least part of the luminescent material (from the inner part) at another part of the light conversion system. Herein, the phrase “during at least part of the time” is included to also include embodiments wherein the luminescent material is not available over the entire ring-shaped arrangement. Would the luminescent material be available over the entire ring-shaped arrangement, the “during at least part of the time” may effectively be the same time as the luminescent material is irradiated from external of the light conversion system. Further, during operation in embodiments the device light may be directed to a first ring-shaped arrangement during a first time period and to a second ring-shaped arrangement during a second time period. This may in embodiments be done altematingly. This may also imply that there are time periods wherein the luminescent material in the first ring-shaped arrangement is not irradiated (during the second time period), and time periods wherein the luminescent material in the second ring-shaped arrangement is not irradiated (during the first time period). The phrase “at least part of the time” may especially relate to the operating time of the system.

Hence, in an operational mode different ring-shaped arrangement may altematingly be irradiated with the device light.

Note that the above embodiments may (thus) also include two or more ringshaped arrangements with the same luminescent material, two or more ring-shaped arrangements with the same luminescent material with at least two different luminescent materials in two of the two or more ring-shaped arrangements, as well as to a single ringshaped arrangement with a single type of luminescent materials, or to a single ring-shaped arrangement with a two or more different types of luminescent materials, which are positioned spatially different (see further also below).

As can be derived from the above, when the device light irradiates another part of the outer face from internal of the light transmissive body, as the device light is partly transmitted by the luminescent material that is irradiated from external by the device light, (a) the luminescent material at the other part of the outer face may be in the same ring-shaped arrangement or in another ring-shaped arrangement, and (b) it can be the same luminescent material or a different luminescent material.

Hence, in embodiments the term “ring-shaped arrangement” may refer to a single ring-shaped arrangement, and in other embodiments the term “ring-shaped arrangement” may refer to at least two ring-shaped arrangements. Especially, ring shaped arrangement may be configured parallel to each other. Further, the term “luminescent material” may refer in embodiments to a single type of luminescent material, and in other embodiments the term “luminescent material” may refer to two or more different types of luminescent material.

In specific embodiments, there may be at least two ring-shaped arrangements and at least two different luminescent materials (comprised by the respective at least two ring-shaped arrangements). Especially, in embodiments the luminescent material may comprise a first luminescent material and a second luminescent material, different from the first luminescent material, wherein the first luminescent material may be configured in at least part of a first ring-shaped arrangement at the outer face, and wherein the second luminescent material may be configured in at least part of a second ring-shaped arrangement at the outer face. Hence, when irradiating the different luminescent materials in the different ring-shaped arrangements, respectively, light with different spectral power distributions will be obtained.

As indicated above, the device light transmitted through one of the luminescent materials at a first position at the of outer face may irradiate at a second position at the outer face another one of the luminescent materials; this device light may at least partly be absorbed by this luminescent material at the second position (and at least partly be converted into luminescent material light), and optionally part of the device light may also be transmitted. The luminescent material at that second part of outer face may thus be irradiated from internal of the light transmissive body. Therefore, in embodiments the first luminescent material, configured in at least part of the first ring-shaped arrangement at the outer face, may be configured to absorb part of the device light received by the first luminescent material. Further, the light generating system may be configured such that device light irradiating the first luminescent material in at least part of the ring-shaped arrangement from external of the light conversion system may (also) at least partly transmitted by the first luminescent material and the inner part and may irradiate during operation of the light generating system during at least part of the time (also) at least part of the second luminescent material (from the inner part) in at least part of the second ring-shaped arrangement at the outer face.

Would in embodiments two (or more) ring-shaped arrangements be applied, which are configured parallel, and configured at different heights, the device light may propagate from one of the ring-shaped arrangements to the other one when one or more of the following applies: (i) the device light is provided with an optical axis penetrating both ringshaped arrangements, for instance with the optical axis not being configured perpendicular to the outer face, and (ii) optics may be applied configured in a hollow light transmissive body.

Therefore, in specific embodiments the light generating system may be configured such that an optical axis (O) of the device light irradiating the first luminescent material in at least part of the ring-shaped arrangement from external of the light conversion system may have an angle (a) unequal to zero with a plane perpendicular to the rotational axis (A). For instance, the angle may be selected from the range of 2-85°, more especially selected from the range of 2-70°, such as selected from the range of 2-45°, more especially 2- 15°, such as in specific embodiments selected from the range of 5-10°.

In further specific embodiments, a conical reflector may be configured inside the inner body. With the conical reflector, the transmitted device light may be redirected (reflected) to a second ring-shaped arrangement. Such conical reflector may be embedded in the solid inner body of a rod, or could be applied at the inner surface of a cylinder (with a relatively thick wall). Alternatively, a conical refractive inner surface, e.g. shaped in the inner surface of a (thick-wall) cylinder, or as an additional refractive optical element with at least one refracting surface that is mounted within a hollow light transmissive body, could be used for the redirection. Note that these two options may result in opposite sides of the cylindrical outer wall where the redirected beam ends up.

In specific embodiments, an actuator may be located in the interior of the cylinder. In specific embodiments, a tiltable reflector may be configured within the cylinder. Hence, in embodiments a controllable redirector of light, such as a tiltable reflector, may be configured in the interior of the cylinder.

As indicated above, the light transmissive body may especially be transmissive for the device light. Hence, the light transmissive body may comprise a light transmissive material, especially a light transparent material.

The light transmissive material may comprise one or more materials selected from the group consisting of a transmissive organic material, such as selected from the group consisting of PE (polyethylene), PP (polypropylene), PEN (polyethylene napthalate), PC (polycarbonate), polyurethanes (PU), polymethylacrylate (PMA), polymethylmethacrylate (PMMA) (Plexiglas or Perspex), polymethacrylimide (PMI), polymethylmethacrylimide (PMMI), styrene acrylonitrile resin (SAN), cellulose acetate butyrate (CAB), silicone, polyvinylchloride (PVC), polyethylene terephthalate (PET), including in an embodiment (PETG) (glycol modified polyethylene terephthalate), PDMS (poly dimethyl siloxane), and COC (cyclo olefin copolymer). Especially, the light transmissive material may comprise an aromatic polyester, or a copolymer thereof, such as e.g. one or more of polycarbonate (PC), poly (methyl)methacrylate (P(M)MA), polyglycolide or polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyethylene adipate (PEA), polyhydroxy alkanoate (PHA), polyhydroxy butyrate (PHB), poly(3-hydroxybutyrate-co-3 -hydroxy valerate) (PHBV), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN). Especially, the light transmissive material may comprise polyethylene terephthalate (PET). Hence, the light transmissive material is especially a polymeric light transmissive material.

However, in another embodiment the light transmissive material may comprise an inorganic material. Especially, the inorganic light transmissive material may be selected from the group consisting of glasses, (fused) quartz, transmissive ceramic materials, and silicones. Also hybrid materials, comprising both inorganic and organic parts may be applied. Especially, the light transmissive material comprises one or more of PMMA, transparent PC, or glass. For instance, the light transmissive material may comprise a ceramic body, like a garnet type of material. In alterative embodiments, the light transmissive material may comprise an alumina material, such as an AI2O3 based material. In embodiments, the light transmissive material may comprise e.g. sapphire. Other materials may also be possible like one or more of CaF2, MgO, BaF2, A3B5O12 garnet, ALON (aluminum oxynitride), MgAhO4 and MgF2.

Especially, the material has a light transmission in the range of 50-100 %, especially in the range of 70-100%, for light having a wavelength selected from the visible wavelength range. Herein, the term “visible light” especially relates to light having a wavelength selected from the range of 380-780 nm.

The transmission (or light permeability) can be determined by providing light at a specific wavelength with a first intensity to the light transmissive material under perpendicular radiation and relating the intensity of the light at that wavelength measured after transmission through the material, to the first intensity of the light provided at that specific wavelength to the material (see also E-208 and E-406 of the CRC Handbook of Chemistry and Physics, 69th edition, 1088-1989).

In specific embodiments, a material may be considered transmissive when the transmission of the radiation at a wavelength or in a wavelength range, especially at a wavelength or in a wavelength range of radiation generated by a source of radiation as herein described, through a 1 mm thick layer of the material, especially even through a 5 mm thick layer of the material, under perpendicular irradiation with said radiation is at least about 20%, such as at least 40%, like at least 60%, such as especially at least 80%, such as at least about 85%, such as even at least about 90%. The light transmissive material may have light guiding or wave guiding properties. Hence, the light transmissive material is herein also indicated as waveguide material or light guide material. The light transmissive material will in general have (some) transmission of one or more of (N)UV, visible and (N)IR radiation, such as in embodiments at least visible light, in a direction perpendicular to the length of the light transmissive material. The transmission of the light transmissive material (as such) for one or more luminescence wavelengths may be at least 80%/cm, such as at least 90%/cm, even more especially at least 95%/cm, such as at least 98%/cm, such as at least 99%/cm. This implies that e.g. a 1 cm³ cubic shaped piece of light transmissive material, under perpendicular irradiation of radiation having a selected luminescence wavelength (such as a wavelength corresponding to an emission maximum of the luminescence of the luminescent material of the light transmissive material), will have a transmission of at least 95%.

Herein, values for transmission especially refer to transmission without taking into account Fresnel losses at interfaces (with e.g. air). Hence, the term “transmission” especially refers to the internal transmission. The internal transmission may e.g. be determined by measuring the transmission of two or more bodies having a different width over which the transmission is measured. Then, based on such measurements the contribution of Fresnel reflection losses and (consequently) the internal transmission can be determined. Hence, especially, the values for transmission indicated herein, disregard Fresnel losses.

In addition to a high transmission for the wavelength(s) of interest, also the scattering for the wavelength(s) may especially be low. Hence, the mean free path for the wavelength of interest only taking into account scattering effects (thus not taking into account possible absorption (which should be low anyhow in view of the high transmission), may be at least 0.5 times the thickness of the body (or of the wall of the body when the body is hollow), such as at least the thickness of the body (or of the wall of the body when the body is hollow), like at least twice the thickness of the body (or of the wall of the body when the body is hollow). For instance, in embodiments the mean free path only taking into account scattering effects may be at least 5 mm, such as at least 10 mm. The wavelength of interest may especially be the wavelength at maximum emission of the device light. The term “mean free path” is especially the average distance a ray will travel before experiencing a scattering event that will change its propagation direction.

In embodiments, the element comprising the light transmissive material may essentially consist of the light transmissive material. In specific embodiments, the element comprising the light transmissive material may be a light transparent element.

Especially, the light transmissive element, such as the light transparent element, may in embodiments have an absorption length and/or a scatter length of at least the thickness (or of the wall of the body when the body is hollow) of the light transmissive element, such as at least twice the thickness (or of the wall of the body when the body is hollow). The absorption length may be defined as the length over which the intensity of the light along a propagation direction due to absorption drops with 1/e. Likewise, the scatter length may be defined as the length along a propagation direction along which light is lost due to scattering and drops thereby with a factor 1/e. Here, the length may thus especially refer to the distance between a primary face and a secondary face of the light transmissive element, with the light transmissive material configured between the primary face and the secondary face. In specific embodiments, the light transmissive body may comprise a light transmissive solid rod, wherein the rod comprises one or more of a polymeric material, a ceramic material, and a single crystal. Hence, the wall or the massive body may be light transmissive for the device light.

As indicated above, in embodiments the light transmissive body may be cylindrically shaped and may optionally host optics. Hence, in embodiments the light transmissive body may comprise a hollow cylinder, wherein the hollow cylinder may comprise a cylinder wall, wherein the cylinder wall comprises the outer face, and wherein the inner part comprises a cavity. Further, especially the light generating system may further comprise first redirection optics. In specific embodiments, the first redirection optics may be configured within the cavity and may be configured to redirect at least part of the device light transmitted by the first luminescent material to the second luminescent material. In specific embodiments, the first redirection optics comprise an ellipsoid reflector. In this way, relatively efficiently transmitted device light may be redirected to another part of the luminescent material, such as luminescent material comprised by another ring-shaped arrangement (or optionally to luminescent material comprised by the same ring-shaped arrangement).

As indicated above, the system may comprise an actuator. The term “actuator” may also refer to a plurality of actuators. An actuator may be configured to rotate the light transmissive body. Further, an actuator may be configured to move the light transmissive body in a direction parallel to the rotational axis. Yet further, an actuator may be used to move a light generating device and/or optics, such that the position of the beam irradiating the luminescent material (at the first position) from external of the light transmissive body may be controlled. The latter actuator may in specific embodiments effectively also be used to control the position of the beam irradiating the luminescent material (at the second position) from internal (after transmission through the luminescent material at the first position (and after transmission through at least part of the light transmissive body, such as a light transmissive wall)). Note that an actuator may also be applied to control optics configured in the cavity of a hollow light transmissive body. An actuator may in embodiments have a single (control) function, and may in other embodiments have more than one (control) functions. As indicated above, in embodiments more than one actuator may be applied. To control the actuator(s) a control system (see further also below) may be applied. Therefore, in embodiments the system may further comprise a control system and an actuator, wherein the actuator is configured to controllable manipulate a beam of device light and/or to control a translational position of the light conversion system along the rotational axis (A). Especially, the control system may be configured to control a position where the device light irradiates the luminescent material by controlling the actuator.

In embodiments, a spectral filter may be configured at the inside of the cylinder, at about the same height as the ring-shaped arrangement. Such spectral filter may be configured to transmit part of the light and reflect another part of the light. For instance, the spectral filter may be configured to transmit at least part of the device light and substantially reflect the luminescent light. This may increase the output of the system, as luminescent material light may not be “lost”. Note that such optical filter may also be configured between the luminescent material and the light transmissive body. This may apply to rods as well as to cylinders.

As indicated above, there may be two or more ring-shaped arrangements. Herein, embodiments comprising two ring-shaped arrangements are described in more detail. However, similarly, this may apply to embodiments with more than two ring-shaped arrangements.

Assuming two or more ring-shaped arrangements, in embodiments the beam of device light and/or the light transmissive body may be controlled such, that in an operational mode the device light irradiates from external only the luminescent material in one of the ring-shaped arrangements, and in another operational mode the device light irradiates from external only the luminescent material in another one of the ring-shaped arrangements. Of course, the device light may be transmitted and then from internal irradiate the luminescent material at a second position, either in the same ring-shaped arrangement and/or in another one of the ring-shaped arrangements. With optics, an angle of the beam of device light may be controlled, allowing to control where the device light irradiates the light conversion system from external. With optics, it is also possible not the change the angle, but change a position where the device light irradiates the light conversion system from external. Therefore, in embodiments the control system may be configured to control the light generating system in a first operational mode or a second operational mode, wherein: (a) in the first operational mode, the first ring-shaped arrangement is configured in a light-receiving relationship with the light generating device, which is configured to irradiate the first luminescent material in at least part of the first ring-shaped arrangement from external of the light conversion system; and (b) in the second operational mode, the second ring-shaped arrangement is configured in a light-receiving relationship with the light generating device, which is configured to irradiate the second luminescent material in at least part of the second ring-shaped arrangement from external of the light conversion system. Of course, the first operational mode is not necessarily preceding the second operational mode. These numbers are essentially only used to distinguish between modes.

As indicated above, in embodiments the light transmissive body may comprise a hollow cylinder. For instance, this may allow arrangement of optics within the hollow cylinder. Such optics may be stationary or controllable, e.g. to (further) control beam direction and propagation. Note that the arrangement of optics is not necessary in some of the embodiments described herein, but belongs to some other embodiments described herein, see also below. Especially, the hollow cylinder may comprises a cylinder wall, wherein the cylinder wall comprises the outer face; wherein the inner part comprises a cavity. Especially, this cavity may be over the entire height of the cylinder and may have a constant inner radius over the height of the cylinder.

In specific embodiments, the light generating system may further comprise second redirection optics, wherein the second redirection optics may especially be configured within the cavity. Further, in specific embodiments the light generating device and the second redirection optics may be configured such that the first luminescent material and/or the second luminescent material are irradiated via the second redirection optics from internal of the light conversion system. In further specific embodiments, the light generating device and the second redirection optics may be configured such that the first luminescent material and/or the second luminescent material are irradiated via the second redirection optics from internal of the light conversion system without being first transmitted by the (first or second) luminescent material. Such latter embodiments may e.g. be provided when the device light enters the cavity not via the wall, but via one of the cylinder openings. Hence, in specific embodiments the hollow cylinder may comprise a cylinder opening, wherein the one or more light generating devices are configured external from the hollow cylinder, and wherein the light generating system may be configured such that the second redirection optics receive at least part of the device light via the cylinder opening. Note that even the one or more light generating devices may be configured within the cylinder. Further controllability may be obtained when using polarized device light having a controllable polarization and optics which direct device light in dependence of the polarization and/or when using device light having a controllable spectral power distribution and (other) optics which may direct device light in dependence of the spectral power distribution. The control system may control the polarization of the device light and/or the spectral power distribution of the device light.

The device light may have a controllable polarization by using controllable polarization optics and/or by using two or more beams of light, optionally generated with two or more light generating devices, wherein the device light in at least two beams differ in polarization. The latter may be due to different types of light sources and/or by using polarization optics.

The device light may have a controllable spectral power distribution, e.g. while the device as such has a controllable spectral power distribution,. However, alternatively or additionally, the device light may have a controllable spectral power distribution by using two or more light generating devices, wherein at least two light generating devices generate device light having different spectral power distributions.

Therefore, in embodiments the one or more light generating devices, configured to generate device light, may have one or more of (i) a controllable spectral power distribution and (ii) a controllable polarization; wherein the second redirection optics may include one or more of (a) a dichroic mirror, and (b) one or more polarization dependent reflectors and/or polarization dependent filters; wherein the light generating system may be configured such that dependent upon one or more of the spectral power distribution and the polarization of the device light, the second redirection optics may direct the device light to the first ring-shaped arrangement and/or the second ring-shaped arrangement; and wherein the light generating system may further comprises the (afore-mentioned) control system configured to control one or more the spectral power distribution and the polarization of the device light.

As indicated above, there may be two or more ring-shaped arrangements, such at two, three, four, five, or six. In specific embodiments, the light generating system may comprise (a) the first luminescent material configured in at least part of the first ring-shaped arrangement at the outer face, (b) the second luminescent material configured in at least part of the second ring-shaped arrangement at the outer face, and (c) a third luminescent material configured in at least part of a third ring-shaped arrangement at the outer face, wherein the first luminescent material, the second luminescent material, and the third luminescent material mutually differ.

Therefore, when there are two or more luminescent materials, they may be selected such that the luminescent material light generated by the respective luminescent material is selected from warm white, cool white, (blue), violet, cyan, green, yellow, amber, orange, and red emitting light generating devices. Warm white may be light having a CCT of at maximum 3500 K, and cool white may be white light having a CCT over 3500 K, though other distinctions are herein not excluded.

The phrase “in at least part of the first ring-shaped arrangement”, and similar phrases (like “in at least part of a third ring-shaped arrangement” may in specific embodiments refer to in the entire first ring-shaped arrangement, etc. Hence, in embodiments, the luminescent material may be provided in a ring-shaped arrangement.

In embodiments, the height of the ring-shaped arrangement may be selected from the range of 0.2-20 mm, such as selected from the range of 0.1-10 mm, like selected from the range of about 1-10 mm. Further, the thickness of the luminescent material (layer) may be selected from the range of 0.1-10 mm, such as selected from the range of 0.1-5 mm, like selected from the range of about 0.1-0.5 mm. Hence, characteristic values of the height of the light transmissive body may be selected from the range of 5-200 mm, such as 10-100 mm. Characteristic values of the height of the ring-shaped arrangement(s) may be selected from the range of 0.2-20 mm, such as 0.1-10 mm, more especially about 1-10 mm. The luminescent material may have a layer thickness e.g. selected from the range of 0.1-0.5 mm. The radius rl may e.g. be selected from the range of 10-100 mm.

The system is especially configured to generate system light. The system light may especially comprise luminescent material light. The system light may also comprise (unconverted) device light. In embodiments, the spectral power distribution of the system light may be controllable. Yet, in embodiments the spectral power distribution of the system light may vary over time with a frequency of at least 50 Hz, such as a frequency of at least 100 Hz, e.g. as a result of switching irradiation hence and forth between different luminescent materials and/or different ring-shaped arrangement, while in average over time (at least in time periods larger than 1/50 seconds) the spectral power distribution is essentially constant. The system may comprise optics to collect, mix, and/or beam shape the light. Hence, in embodiments the light generating system is especially configured to generate system light comprising one or more of the device light and the luminescent material light; wherein the light generating system further optionally comprises system optics configured (a) to receive at least part of the device light and/or at least part of the luminescent material light, and (b) to beam shape the system light. In embodiments, the system optics comprises a light homogenization device, wherein the light homogenization device is selected from the group of a diffuser, an integrating rod, an integrating fly-eye lens array, and Koehler optics.

Diffusers may be subdivided into volume diffusers and/or surface diffusers. Of special interest may be flat-top diffusers, which have a specific design (generally as a surface texture) to achieve this (as in contrast to Lambertian diffusers as resulting from random patterns). Homogenization may further be realized by micro lens arrays. Integrating fly-eye lens arrays may be used in pairs that are well aligned with respect to each other and are thus a more specific application of lens arrays (in general with still relatively large lenses, although the lens diameter is typically about an order of magnitude smaller than the beam diameter).

Further, the system may comprise a control infrastructure to check whether the system is operating as desired or predefined. For instance, in this way a feed-back (or a feedforward) system may be provided, which may increase reliability and safety.

In embodiments, the system may further comprise a light output sensor for determining a device output signal being correlated with an output of device light emitted by the light generating device; a luminescent material light sensor for determining a luminescent material light signal being correlated with an output of luminescent material light emitted by the luminescent material; and a control system which is adapted for receiving the device output signal and the a luminescent material light signal, for determining a safe-to-operate parameter based on the device output signal and the a luminescent material light signal, and for controlling the operation of the light generating device based on a comparison between the safe-to-operate parameter and at least one predefined threshold. For instance, in embodiments the light output sensor may sense a radiant flux of the device light. In embodiments, the luminescent material light sensor may sense one or more of a radiant flux and spectral power distribution (or at least part thereof) of the luminescent material light. Yet, in embodiments a sensor may be configured to sense both device light and luminescent material light (and e.g. determine or be used to determine a ratio of the intensity (such as radiant flux) of luminescent material light and the total intensity (such as total radiant flux) of the system light.

Alternatively or additionally, the system may further comprise a sensor, configured to sense one or more of a rotation of the light transmissive body, a position of the luminescent material, and the luminescent material light, and generate a related sensor signal; wherein the control system is configured to control a controllable parameter of the light generating system in dependence of the sensor signal, wherein the controllable parameter is selected from the group of a propagation direction of a beam of device light, a translational position of the light conversion system along the rotational axis (A), a controllable arrangement of position of first redirection optics, a controllable arrangement of position of third redirection optics, a spectral power distribution of the first device light, a polarization of the first device light, an output of the one or more light generating devices.

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.

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. In other embodiments, the lighting device may comprise an automotive lighting device. Hence, in an aspect the invention also provides a lighting device selected from the group of a lamp, a luminaire, a projector device, an automotive headlamp, comprising the light generating system as defined herein. In specific embodiments, the lamp may be a spot light (or other type of non-imaging (lighting) device. 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 device, the light conversion system, an actuator, a sensor, etc.

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.

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. 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 “violet light” or “violet emission”, and similar terms, may especially relate to light having a wavelength in the range of about 380-440 nm. In specific embodiments, the violet light may have a centroid wavelength in the 380-440 nm range. The terms “green light” or “green emission”, and similar terms, may especially relate to light having a wavelength in the range of about 490-560 nm. In specific embodiments, the green light may have a centroid wavelength in the 490-560 nm range. The terms “yellow light” or “yellow emission”, and similar terms, may especially relate to light having a wavelength in the range of about 560-590 nm. In specific embodiments, the yellow light may have a centroid wavelength in the 560-590 nm range. The terms “orange light” or “orange emission”, and similar terms, may especially relate to light having a wavelength in the range of about 590-620 nm. In specific embodiments, the orange light may have a centroid wavelength in the 590-620 nm range. The terms “red light” or “red emission”, and similar terms, may especially relate to light having a wavelength in the range of about 620-750 nm. In specific embodiments, the red light may have a centroid wavelength in the 620-750 nm range. The terms “cyan light” or “cyan emission”, and similar terms, especially relate to light having a wavelength in the range of about 490-520 nm. In specific embodiments, the cyan light may have a centroid wavelength in the 490-520 nm range. The terms “amber light” or “amber emission”, and similar terms, may especially relate to light having a wavelength in the range of about 585-605 nm, such as about 590-600 nm. In specific embodiments, the amber light may have a centroid wavelength in the 585-605 nm range. 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, which 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.

The term “centroid wavelength”, also indicated as c, is known in the art, and refers to the wavelength value where half of the light energy is at shorter and half the energy is at longer wavelengths; the value is stated in nanometers (nm). It is the wavelength that divides the integral of a spectral power distribution into two equal parts as expressed by the formula Ac = X X*I(X) / (S I( X)), where the summation is over the wavelength range of interest, and I(X) is the spectral energy density (i.e. the integration of the product of the wavelength and the intensity over the emission band normalized to the integrated intensity). The centroid wavelength may e.g. be determined at operation conditions.

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”.

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, la-le schematically depict some embodiment of the system;

Figs. 2a-2b schematically depict some further embodiments of the system; likewise,

Figs. 3a-3b, and Fig. 4 schematically depict some embodiments of the system. Fig. 5 schematically depict some application embodiments.

The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. la-le schematically depict some embodiments of a light generating system 1000. Especially, the light generating system 1000 may comprise a light generating device 100 and a light conversion system 2000. The light generating device 100 may be configured to generate device light 101. Further, the light generating device 100 may especially comprise a solid state light source, such as comprising in embodiments one or more of a laser light source and a superluminescent diode. In specific embodiments the device light may comprise (especially be) laser light. Further, the light conversion system 2000 may comprise a light transmissive body 2100 and a luminescent material 200. Especially, the light transmissive body 2100 may be configured rotatable about a rotational axis A; the light transmissive body 2100 may comprise (i) an outer face 2110 configured at a distance rl from the rotational axis A, and (ii) an inner part 2120 enclosed by the outer face 2110, wherein at least part of the inner part 2120 is light transmissive for the device light 101. Yet, in embodiments the luminescent material 200 may be configured to convert at least part of the device light 101 received by the luminescent material 200 into luminescent material light 201. Especially, the luminescent material 200 may be configured at a part of the outer face 2110. In embodiments, the light generating system 1000 may be configured such that during operation of the light generating system 1000 during at least part of the time at least part of the device light irradiates at least part of the luminescent material 200 from the inner part 2120. Figs, la and 1c may show embodiments of a hollow cylinder or a massive rod. Figs, lb, Id, and le schematically depict embodiments of a hollow cylinder in cross- sectional view. In embodiments, the light transmissive body 2100 may comprise a light transmissive solid rod, wherein the rod may comprise one or more of a polymeric material, a ceramic material, and a single crystal. Reference H refers to the height of the light transmissive body. Characteristic values of the height H may be selected from the range of 5- 200 mm, such as 10-100 mm. Reference Hl refers to the height of a ring-shaped arrangement. Characteristic values of the height of the ring-shaped arrangement(s) may be selected from the range of 1-10 mm. The luminescent material may have a layer thickness dl, see Fig. 3a. Characteristic values may be selected from the range of 0.1-0.5 mm. The radius rl may e.g. be selected from the range of 10-100 mm.

The light conversion system 2000 may thus have a circular cross-sectional shape perpendicular to the rotational axis A. Especially the luminescent material 200 may be configured in at least part of a ring-shaped arrangement 2130 at the outer face 2110.

In embodiments, the luminescent material 200, configured in at least part of the ring-shaped arrangement 2130 at the outer face 2110, may be configured to absorb part of the device light 101 received by the luminescent material 200; wherein the light generating system 1000 may be configured such that device light 101 irradiating the luminescent material 200 in at least part of the ring-shaped arrangement 2130 from external of the light conversion system 2000 is at least partly transmitted by the luminescent material 200 and the inner part 2120 and irradiates during operation of the light generating system 1000 during at least part of the time also at least part of the luminescent material 200 from the inner part 2120 at another part of the light conversion system 2000.

Referring to e.g. Figs, la and 1c, the luminescent material 200 may comprise a first luminescent material 210 and a second luminescent material 220, different from the first luminescent material 210, wherein the first luminescent material 210 may be configured in at least part of a first ring-shaped arrangement 2131 at the outer face 2110, and wherein the second luminescent material 210 may be configured in at least part of a second ring-shaped arrangement 2132 at the outer face 2110. In both drawings, by way of example three ringshaped arrangements are depicted. However, there may be less or more ring-shaped arrangements.

Therefore, in embodiments the light generating system 1000 may comprise (a) the first luminescent material 210 configured in at least part of the first ring-shaped arrangement 2131 at the outer face 2110, and (b) the second luminescent material 210 configured in at least part of the second ring-shaped arrangement 2132 at the outer face 2110, and c a third luminescent material 230 configured in at least part of a third ring-shaped arrangement 2133 at the outer face 2110. Especially, the first luminescent material 210, the second luminescent material 220, and the third luminescent material 230 may mutually differ.

Referring to e.g. Fig. 1c, the first luminescent material 210, configured in at least part of the first ring-shaped arrangement 2131 at the outer face 2110, may be configured to absorb part of the device light 101 received by the first luminescent material 210; wherein the light generating system 1000 may be configured such that device light 101 irradiating the first luminescent material 210 in at least part of the ring-shaped arrangement 2130 from external of the light conversion system 2000 is also at least partly transmitted by the first luminescent material 210 and the inner part 2120 and irradiates during operation of the light generating system 1000 during at least part of the time also at least part of the second luminescent material 220 from the inner part 2120 in at least part of the second ring-shaped arrangement 2132 at the outer face 2110. For instance, in embodiments the light generating system 1000 may be configured such that an optical axis O of the device light 101 irradiating the first luminescent material 210 in at least part of the ring-shaped arrangement 2130 from external of the light conversion system 2000 has an angle a unequal to zero with a plane perpendicular to the rotational axis A.

Referring to Fig. lb, in embodiments, a spectral filter 510 may be configured at the inside of the cylinder, at about the same height as the ring-shaped arrangement. Such spectral filter may be configured to transmit part of the light and reflect another part of the light. For instance, the spectral filter may be configured to transmit at least part of the device light and substantially reflect the luminescent light. Here, the spectral filter 510 is at the inside of the cylinder. However, such spectral filter 510 may also be configured between the light transmissive body and the luminescent material. Referring to e.g. Figs, lb, Id, and le, the light transmissive body 2100 may comprise a hollow cylinder 2180. The hollow cylinder 2180 may comprise a cylinder wall 2181. Especially, the cylinder wall 2181 may comprise the outer face 2110. Further, the inner part 2120 may comprise a cavity 2182.

Referring to e.g. Figs, lb, Id, and le, the light generating system 1000 may further comprise first redirection optics 2200. In embodiments, the first redirection optics 2200 may be configured within the cavity 2182 and are configured to redirect at least part of the device light 101 transmitted by the first luminescent material 210 to the second luminescent material 220. Referring to Fig. le, the first redirection optics 2200 comprise an ellipsoid reflector.

Referring to e.g. Figs. 2a-2b, the light generating system 1000 may further comprise a control system 300 and an actuator 320, wherein the actuator 320 may be configured to controllable manipulate a beam of device light 101 and/or to control a translational position of the light conversion system 2000 along the rotational axis A. Especially, the control system 300 may be configured to control a position where the device light 101 irradiates the luminescent material 200 by controlling the actuator 320.

For instance, in embodiments the control system 300 may be configured to control the lighting generating system 1000 in a first operational mode or a second operational mode, wherein: a in the first operational mode, the first ring-shaped arrangement 2131 may be configured in a light-receiving relationship with the light generating device 100, which may be configured to irradiate the first luminescent material 210 in at least part of the first ring-shaped arrangement 2131 from external of the light conversion system 2000; and b in the second operational mode, the second ring-shaped arrangement 2132 may be configured in a light-receiving relationship with the light generating device 100, which may be configured to irradiate the second luminescent material 220 in at least part of the second ringshaped arrangement 2132 from external of the light conversion system 2000. In both drawings, by way of example two ring-shaped arrangements are depicted. However, there may also be three or more ring-shaped arrangements see also above. In Fig. 2a, an embodiment is shown wherein the beam is manipulated. In Fig. 2b, an embodiment is depicted wherein the light transmissive body is translated along the axis A.

Hence, referring to Figs. la-2b, on the surface of a hollow cylinder different parallel rings of phosphor with different colors may be applied. There is no restriction imposed on the gap size between the phosphor rings: phosphor rings may or may not be directly adjacent to the first and/or second ring. Further, an interface between the phosphor and the cylinder is transparent for the excitation light blue, and substantially reflective for the converted light. This can be achieved by applying a dichroic mirror coating on a transparent cylinder. In analogy with the reflective rotating cylinder, the transmissive rotating cylinder must also be a good thermal conductor. A viable option for a heat conductive transparent material is sapphire ~25W/mK at room temperature, which can be supplied in tubular shapes. In embodiments, a partial conversion takes place in the phosphor rings. Especially, in embodiments on parts of the inner cylinder, where there are no phosphor rings on the outside, cooling fins can be applied.

In embodiments, a primary color tunable beam is generated similarly to the generation with the reflective rotating cylinder. In this case, however, since the conversion of pump light into the first color tunable beam is partial, part of the excitation laser beam will be transmitted through the transparent rotating cylinder. The transmitted excitation laser beam can be used to generate a second beam with different color or may be re-used without further luminescent conversion.

For the generation of additional color tunable beams based on the transmitted not-converted part of the incident beam there are various possible options.

In embodiments, an incident laser excitation beam is normal to rotating cylinder surface in the plane through the rotation axis and internal mirror - see e.g. Figs Idle. Inside the hollow transparent rotating cylinder there may be a static i.e., non-rotating specular mirror which reflects the transmitted excitation laser beam to a different phosphor ring, i.e. a different color, in a different direction. In Figs Id-le the second converted beam is directed at e.g. 90° from the first converted beam but is not limited to this angle.

In embodiments, an internal reflector might be rotatable (principal rotation axis perpendicular to rotation axis of cylinder) and/or translatable (translation along the axis of the cylinder and/or along the axis of the incident beam) so that the second phosphor ring, i.e. the color of the second beam, can be selected.

In embodiments, in order to focus the transmitted laser beam to a spot on the second phosphor ring, the shape of the inside static mirror may preferably be ellipsoidal and arranged such that the phosphor excitation spots are at the 2 focus points of the ellipsoidal mirror. This configuration is in particular beneficial in case of a scattering luminescent converter layer that the laser beam has partly transmitted through see also above.

In embodiments, the color of the first beam can be selected by shifting the rotating cylinder along the rotation axis. The color of the second beam can be selected independently from the first beam by rotating and/or translating the internal mirror. Alternatively or additionally to using a mirror to redirect and/or focus the transmitted pump beam inside the cylinder, one or more lenses may be used to collect the transmitted pump light and focus this elsewhere on a second luminescent converter ring from the inside of the cylinder. Alternatively or additionally, the transmitted pump beam is not projected onto a further luminescent converter ring but is used without further conversion and therefore just projected to a location either at the cylinder wall or at one of the two ends of the cylinder where it can leave the cylinder to be recombined with the first converted beam. Combinations of lenses and reflectors may be used as well to project the transmitted laser beam inside the cylinder on another luminescent converter ring or transparent ring in case the pump light is to be used without further conversion.

Referring to Fig. 3a, an alternative embodiment, that does not necessarily involve a translational mechanical motion of the cylinder nor a translation of the incident pump beam is shown. Pumping may be done with a mix of two blue light generating devices, such as lasers, with wavelength XI and X2 or polarization pl and p2. A dichroic beam splitter (or polarizing beam splitter) may be provided with a 90° turning prism, indicated with the dashed line. Hence, a dichroic beam splitter (or polarizing beam splitter), indicated with the dashed line, is provided with a 90° turning prism or mirror. The assembly may be stationary inside the rotation cylinder. The combined beam is split by the dichroic beam splitter. The two blue beams of device light 101 are directed to two phosphor rings on the rotating cylinder, as illustrated. By varying the power in the pump wavelengths XI and X2 the spectrum of the total output can be varied.

Referring to Fig. 3a, the luminescent material may have a layer thickness dl, e.g. selected from the range of 0.1-0.5 mm. Here, the luminescent material protrudes from the light transmissive body, however, the luminescent material (in e.g. a ring-shaped arrangement) may also be available in a (ring-shaped) recess in the outer face 2110.

Note that the radius of the light transmissive body may essentially be the distance for the rotational axis to the outer face 2110. On the outer face, the luminescent material may be configured. In other embodiments, locally there may be a recess in the outer face, would the luminescent material be configured in a recess in the outer face.

Fig. 3 A only shows the option for two different wavelengths. Similarly, two different polarizations may be applied, using a polarizing beam splitter.

Referring to Fig. 3b, an embodiment that does not necessarily involve a translational mechanical motion of the cylinder nor a translation of the incident pump beam is schematically depicted. Pumping may be done with a mix of two blue light generating devices, such as lasers, with wavelength XI and X2 or polarization pl and p2. A 90° turning prism is provided with an internal dichroic coating that can separate these two wavelengths/polarizations. The prism is stationary inside the rotation cylinder. The combined beam pumps a first phosphor. The unconverted transmitted blue light is separated by the turning prism and the respective blue wavelengths pump a second and a third phosphor, as illustrated. By varying the power in the pump wavelengths XI and X2 the spectrum color of the total output can be varied.

Similarly, different polarizations may be applied. Then, the device light may be provided with two different polarizations or a controllable polarization. The device light having different polarizations may have the same pump wavelength. The different polarizations may especially be s-polarized light and p-polarized light. In such embodiments, at the position of the dichroic beam splitter, a polarizing beam splitter may be configured. Further, the picture on the right in Figs. 3a-3b is not necessarily relevant, as the distinction is not based on pump wavelength, but on polarization, essentially irrespective of the pump wavelength.

Hence, in embodiments of the light generating system 1000 the light transmissive body 2100 may comprise a hollow cylinder 2180. Especially, the hollow cylinder 2180 may comprise a cylinder wall 2181, wherein the cylinder wall 2181 may comprise the outer face 2110. Especially, the inner part 2120 may comprise a cavity 2182. Especially, in embodiments the light generating system 1000 may further comprise second redirection optics 2300. In embodiments, the second redirection optics 2300 are configured within the cavity 2182; wherein the light generating device 100 and the second redirection optics 2300 are configured such that the first luminescent material 210 and/or the second luminescent material 220 are irradiated via the second redirection optics 2300 from internal of the light conversion system 2000 and without being first transmitted by the first or second luminescent material.

In embodiments, the hollow cylinder 2180 may comprise a cylinder opening 2183, wherein the one or more light generating devices 100 are configured external from the hollow cylinder 2180, and wherein the light generating system 1000 may be configured such that the second redirection optics 2300 receive at least part of the device light 101 via the cylinder opening 2183.

Referring to Figs. 3a-3b, the one or more light generating devices 100, configured to generate device light 101, may have one or more of (i) a controllable spectral power distribution and (ii) a controllable polarization. Especially, in embodiments the second redirection optics 2300 may include one or more of a dichroic mirror, and one or more polarization dependent reflectors and/or polarization dependent filters. Further, in embodiments the light generating system 1000 may be configured such that dependent upon one or more of the spectral power distribution and the polarization of the device light 101, the second redirection optics 2300 direct the device light 101 to the first ring-shaped arrangement 2131 and/or the second ring-shaped arrangement 2132. Especially, in embodiments the light generating system 1000 may further comprise a control system 300 configured to control one or more the spectral power distribution and the polarization of the device light 101.

Referring to e.g. Figs. 3a-3b the invention may provide amongst others a (tunable) laser light engine with rotating cylinder or rotating rod. Tunability may be in the spectral power distribution of the device light (as depicted) or in the polarization (not depicted, but described).

Referring to Fig. Id and Fig. 4, the light generating system 1000 may be configured to generate system light 1001 comprising one or more of the device light 101 and the luminescent material light 201. Especially, the light generating system 1000 may further comprise system optics 2400 configured to receive at least part of the device light 101 and/or at least part of the luminescent material light 201, and to beam shape the system light 1001. In Fig. Id, references 2401 refers to specular reflectors. Reference 2402 refers to a dichroic mirror, which may be reflective for first luminescent material light 211 and transmissive for second luminescent material light 221. Other constructions may also be possible. In Fig. 4, the light transmissive body 2100 is configured in a hollow reflector. A hole in the wall of the hollow reflector may allow entry of the device light 101.

Referring to e.g. Figs, la, 1c, 2b, 3a, and 3d, over the entire ring the ringshaped arrangement 2130 may comprise the luminescent material 200, especially having an essentially constant height Hl, and especially having an essentially constant thickness dl.

In embodiments, the system optics 2400 may comprise a light homogenization device, wherein the light homogenization device is selected from the group of a diffuser, an integrating rod, an integrating fly-eye lens array, and Koehler optics.

In embodiments, not depicted, the system 1000 may further comprise a light output sensor for determining a device output signal being correlated with an output of device light 101 emitted by the light generating device 100. The system 1000 may further comprise; a luminescent material light sensor for determining a luminescent material light signal being correlated with an output of luminescent material light 201 emitted by the luminescent material 200. Especially, a control system 300 may be is adapted for receiving the device output signal and the a luminescent material light signal, for determining a safe-to-operate parameter based on the device output signal and the a luminescent material light signal, and for controlling the operation of the light generating device 100 based on a comparison between the safe-to-operate parameter and at least one predefined threshold.

In embodiments, not depicted, the system may further comprise a sensor, configured to sense one or more of a rotation of the light transmissive body 2100, a position of the luminescent material 200, and the luminescent material light 201, and generate a related sensor signal; wherein the control system 300 may be configured to control a controllable parameter of the light generating system in dependence of the sensor signal, wherein the controllable parameter is selected from the group of a propagation direction of a beam of device light 101, a translational position of the light conversion system 2000 along the rotational axis A, a controllable arrangement of position of first redirection optics 2200, a controllable arrangement of position of third redirection optics 2200, a spectral power distribution of the first device light 101, a polarization of the first device light 101, an output of the one or more light generating devices 100.

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. Reference 1305 refers to a floor and reference 1310 to a ceiling; reference 1307 refers to a wall.

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 a light generating device (100) and a light conversion system (2000), wherein: the light generating device (100) is configured to generate device light (101); wherein the light generating device (100) comprises a solid state light source, wherein the solid state light source comprises one or more of a laser light source and a superluminescent diode; the light conversion system (2000) comprises a light transmissive body (2100) and a luminescent material (200); the light transmissive body (2100) is configured rotatable about a rotational axis (A); the light transmissive body (2100) comprises (i) an outer face (2110) configured at a distance (rl) from the rotational axis (A), and (ii) an inner part (2120) enclosed by the outer face (2110), wherein at least part of the inner part (2120) is light transmissive for the device light (101); the luminescent material (200) is configured to convert at least part of the device light (101) received by the luminescent material (200) into luminescent material light (201); wherein the luminescent material (200) is configured at a part of the outer face (2110); wherein the light conversion system (2000) has a circular cross-sectional shape; wherein the luminescent material (200) is configured in at least part of a ring-shaped arrangement (2130) at the outer face (2110) of the light transmissive body (2100); and the light generating system (1000) is configured such that during operation of the light generating system (1000) during at least part of the time at least part of the device light irradiates at least part of the luminescent material (200) from the inner part (2120).

2. The light generating system (1000) according to claim 1, wherein the light generating device (100) comprises a laser diode.

3. The light generating system (1000) according to claim 2, wherein the luminescent material (200), configured in at least part of the ring-shaped arrangement (2130) at the outer face (2110), is configured to absorb part of the device light (101) received by the luminescent material (200); wherein the light generating system (1000) is configured such that device light (101) irradiating the luminescent material (200) in at least part of the ringshaped arrangement (2130) from external of the light conversion system (2000) is at least partly transmitted by the luminescent material (200) and the inner part (2120) and irradiates during operation of the light generating system (1000) during at least part of the time at least part of the luminescent material (200) at another part of the light conversion system (2000).

4. The light generating system (1000) according to any one of the preceding claims 2-3, wherein the luminescent material (200) comprises a first luminescent material (210) and a second luminescent material (220), different from the first luminescent material (210), wherein the first luminescent material (210) is configured in at least part of a first ringshaped arrangement (2131) at the outer face (2110), and wherein the second luminescent material (210) is configured in at least part of a second ring-shaped arrangement (2132) at the outer face (2110).

5. The light generating system (1000) according to claim 4, wherein the first luminescent material (210), configured in at least part of the first ring-shaped arrangement (2131) at the outer face (2110), is configured to absorb part of the device light (101) received by the first luminescent material (210); wherein the light generating system (1000) is configured such that device light (101) irradiating the first luminescent material (210) in at least part of the ring-shaped arrangement (2130) from external of the light conversion system (2000) is at least partly transmitted by the first luminescent material (210) and the inner part (2120) and irradiates during operation of the light generating system (1000) during at least part of the time at least part of the second luminescent material (220) in at least part of the second ring-shaped arrangement (2132) at the outer face (2110).

6. The light generating system (1000) according to claim 5, wherein the light generating system (1000) is configured such that an optical axis (O) of the device light (101) irradiating the first luminescent material (210) in at least part of the ring-shaped arrangement (2130) from external of the light conversion system (2000) has an angle (a) unequal to zero with a plane perpendicular to the rotational axis (A).

7. The light generating system (1000) according to any one of the preceding claims 5-6, wherein the light transmissive body (2100) comprises a hollow cylinder (2180), wherein the hollow cylinder (2180) comprises a cylinder wall (2181), wherein the cylinder wall (2181) comprises the outer face (2110); wherein the inner part (2120) comprises a cavity (2182); wherein the light generating system (1000) further comprises first redirection optics (2200); wherein the first redirection optics (2200) are configured within the cavity (2182) and are configured to redirect at least part of the device light (101) transmitted by the first luminescent material (210) to the second luminescent material (220).

8. The light generating system (1000) according to claim 7, wherein the first redirection optics (2200) comprise an ellipsoid reflector.

9. The light generating system (1000) according to any one of the preceding claims 4-8, further comprising a control system (300) and an actuator (320), wherein the actuator (320) is configured to controllable manipulate a beam of device light (101) and/or to control a translational position of the light conversion system (2000) along the rotational axis (A); wherein the control system (300) is configured to control a position where the device light (101) irradiates the luminescent material (200) by controlling the actuator (320).

10. The light generating system (1000) according to claim 9, wherein the control system (300) is configured to control the lighting generating system (1000) in a first operational mode or a second operational mode, wherein: in the first operational mode, the first ring-shaped arrangement (2131) is configured in a light-receiving relationship with the light generating device (100), which is configured to irradiate the first luminescent material (210) in at least part of the first ringshaped arrangement (2131) from external of the light conversion system (2000); and in the second operational mode, the second ring-shaped arrangement (2132) is configured in a light-receiving relationship with the light generating device (100), which is configured to irradiate the second luminescent material (220) in at least part of the second ring-shaped arrangement (2132) from external of the light conversion system (2000).

11. The light generating system (1000) according to claim 4, wherein the light transmissive body (2100) comprises a hollow cylinder (2180), wherein the hollow cylinder (2180) comprises a cylinder wall (2181), wherein the cylinder wall (2181) comprises the outer face (2110); wherein the inner part (2120) comprises a cavity (2182); wherein the light generating system (1000) further comprises second redirection optics (2300); wherein the second redirection optics (2300) are configured within the cavity (2182); wherein the light generating device (100) and the second redirection optics (2300) are configured such that the first luminescent material (210) and/or the second luminescent material (220) are irradiated via the second redirection optics (2300) from internal of the light conversion system (2000).

12. The light generating system (1000) according to claim 11, wherein the one or more light generating devices (100), configured to generate device light (101), have one or more of (i) a controllable spectral power distribution and (ii) a controllable polarization; wherein the second redirection optics (2300) include one or more of (a) a dichroic mirror, and (b) one or more polarization dependent reflectors and/or polarization dependent filters; wherein the light generating system (1000) is configured such that dependent upon one or more of the spectral power distribution and the polarization of the device light (101), the second redirection optics (2300) direct the device light (101) to the first ring-shaped arrangement (2131) and/or the second ring-shaped arrangement (2132); wherein the light generating system (1000) further comprises a control system (300) configured to control one or more the spectral power distribution and the polarization of the device light (101).

13. The light generating system (1000) according to any one of the preceding claims, comprising (a) the first luminescent material (210) configured in at least part of the first ring-shaped arrangement (2131) at the outer face (2110), and (b) the second luminescent material (210) configured in at least part of the second ring-shaped arrangement (2132) at the outer face (2110), as defined in claim 4, and (c) a third luminescent material (230) configured in at least part of a third ring-shaped arrangement (2133) at the outer face (2110); wherein the first luminescent material (210), the second luminescent material (220), and the third luminescent material (230) mutually differ.

14. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) is configured to generate system light (1001) comprising one or more of the device light (101) and the luminescent material light (201); wherein the light generating system (1000) further comprises system optics (2400) configured (a) to receive at least part of the device light (101) and/or at least part of the luminescent material light (201), and (b) to beam shape the system light (1001).

15. A lighting device (1200) selected from the group of a lamp (1), a luminaire

(2), a projector device (3), an automotive headlamp, comprising the light generating system (1000) according to any one of the preceding claims.