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WO2017032585A1 - Lentille optique avec structure de dent - Google Patents

Lentille optique avec structure de dent Download PDF

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Publication number
WO2017032585A1
WO2017032585A1 PCT/EP2016/068874 EP2016068874W WO2017032585A1 WO 2017032585 A1 WO2017032585 A1 WO 2017032585A1 EP 2016068874 W EP2016068874 W EP 2016068874W WO 2017032585 A1 WO2017032585 A1 WO 2017032585A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
optical lens
lens
optical axis
tooth
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2016/068874
Other languages
English (en)
Inventor
Oliver Dross
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Signify Holding BV
Original Assignee
Philips Lighting Holding BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Philips Lighting Holding BV filed Critical Philips Lighting Holding BV
Publication of WO2017032585A1 publication Critical patent/WO2017032585A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V5/00—Refractors for light sources
    • F21V5/04—Refractors for light sources of lens shape
    • F21V5/045—Refractors for light sources of lens shape the lens having discontinuous faces, e.g. Fresnel lenses
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Definitions

  • the present invention generally relates to the field of optical lenses and lighting devices comprising such lenses. More specifically, the invention relates to an optical lens having a light-exiting surface with a peripheral, convex portion and a central portion provided with at least one tooth.
  • LEDs light-emitting diodes
  • Most LEDs are known to provide an essentially Lambertian intensity distribution, i.e., to emit light with an intensity that decreases with the cosine of the divergence angle from the optical axis (or main direction of light emission) of the LED.
  • intensity distribution may be a drawback for applications such as e.g. vehicular lamps or street lighting.
  • Various types of lens arrangements are therefore known to be employed for mitigating light intensity distributions having a relatively high optical axis intensity.
  • a vehicular lamp having a lens that is arranged to redirect the emitted light.
  • the lens comprises a concave surface portion and a convex surface portion, wherein the concave surface portion is positioned closer to the optical axis of the lamp and the convex surface portion is positioned outside of the concave surface portion.
  • US 2010/027271 discloses a light-directing lensing member for off-axial preferential-side distribution of light. It shows a central portion with an inclined exit surface and an asymmetrical outer portion that may be convex, designed to realize a lighting appartus which produces a desired illumination pattern with a maximum amount of emitted light towards an area intended to be illuminated and with improved unifomity of the light distribution. Even though such a vehicular lamp may provide a relatively well-tuned intensity distribution, it is still desirable to provide at least alternative, and if possible improved, optical lenses and lighting devices capable of providing a desired intensity distribution.
  • an optical lens and a lighting device having the features defined in the independent claims are provided.
  • Preferable embodiments are defined in the dependent claims.
  • an optical lens that is adapted to transmit light from a light source.
  • the optical lens comprises a light-transmitting body and a light-exiting surface from which light is output from the lens.
  • the light-exiting surface is arranged on the body and comprises a peripheral portion and a central portion relative to an optical axis of the lens.
  • the peripheral portion is a convex portion, wherein the central portion comprises at least one tooth that is formed by a main surface, leaning towards the optical axis, and an edge surface, wherein the tooth extends at least partly around the optical axis.
  • the projection of the light-transmitting body on a plane perpendicular to the optical axis forms a footprint of the optical lens, said footprint being elongated in the direction of the peripheral portion.
  • a lighting device comprises a light source and an optical lens according to the first aspect.
  • the intensity distribution of light emitted from the optical lens can be adjusted by providing the central portion with at least one tooth having a main surface, or active surface, that is adapted to redirect the light off axis, i.e., diverge light away from the optical axis.
  • the intensity may be distributed over a larger angular interval from the optical axis. This is a particular advantage when using light sources, such as LEDs, which may emit light with a Lambertian intensity distribution that decreases with increasing divergence angle from the optical axis.
  • an optical lens may be achieved that mitigates the effect of a Lambertian intensity distribution in applications in which a wider intensity distribution is preferable or required.
  • Such distribution of light may for example be advantageous for applications including e.g. automotive lighting, rear combination lamps and street lighting.
  • the tooth may alternatively or interchangeably be referred to as a step or discontinuity in the central portion of the light-exiting surface, wherein the main surface and the edge surface of the tooth may adjoin each other in an edge that may protrude (or stick out) from the body of the lens.
  • the main surface i.e. the larger one of the two surfaces forming the tooth, may also be referred to as the active surface, indicating that more light may exit though the main surface than through the edge surface.
  • the tooth may e.g. form part of a Fresnel structure in which the main surface may form part of the active, light-directing surface of the Fresnel structure.
  • the amount of light exiting through the edge surface and the main surface, respectively, may depend on the relative size of the surfaces and their respective orientation relative to the optical axis.
  • optical axis may in the context of the present application refer to a line or direction along which light may exit the optical lens.
  • the optical lens may have at least some degree of symmetry along the optical axis.
  • the light source may be arranged along the optical axis.
  • peripheral and central should, in the context of the present application, each be understood in relation to the optical axis.
  • the central portion may be arranged closer to the optical axis whereas the peripheral portion may be arranged farther away from the optical axis, relative to each other.
  • the outer contour of the light-transmitting body may be understood by studying a contour or shape of a footprint of the optical lens.
  • the contour may e.g. have the shape of an oval, ellipse or a peanut that is centered around the optical axis.
  • a radius, or radial distance between the contour and the optical axis may be larger for the peripheral portion than for the central portion of such a shape.
  • the outer contour may be realized by a shape having a lower curvature at the central portion than at the peripheral portion of the footprint.
  • the light-transmitting body may e.g.
  • the footprint of the peripheral portion(s) may have a positive curvature, i.e., a convex contour in relation to the optical axis, whereas the footprint of the central portion may have a negative curvature, i.e., a concave contour in relation to the optical axis.
  • the shape of the outer contour of the light-transmitting body may further be described by introducing a polar coordinate system having its origin on the optical axis, wherein each point on the outer curvature of the footprint may be described by a radius and a polar angle.
  • the footprint may in one example have a maximum radius at e.g. 0 degrees and 180 degrees, and a minimum radius at e.g. 90 degrees and 270 degrees.
  • the edge surface may e.g. extend in a plane essentially parallel to the optical axis so as to reduce the amount of light reaching the edge surface from the light source, whereas the main surface is arranged to face the optical axis.
  • the main surface extends along a plane having a normal that intersect or is directed towards the optical axis. Light exiting the optical lens through the main surface may thereby be redirected or diverged away from the optical axis and hence allow for a reduction of the light intensity in a forward direction, i.e. along the optical axis.
  • the main surface of the tooth may be a planar surface or a curved surface, and may e.g. form part of a planar Fresnel lens.
  • the central portion may further comprise a plurality of teeth, wherein the main surfaces of the teeth may be identical to each other or differ in terms of e.g. size, lateral extension, curvature or orientation relative to the optical axis.
  • the peripheral portion may e.g. be smoother than the central portion and may at least partly conform to the shape of a convex lens, and the relative area of the peripheral portion and the central portion may be chosen according to the intensity distribution of the light emitted by the light source.
  • a wider intensity distribution of light emitted from the light source may require a central portion having a relatively larger area, and vice versa.
  • a peripheral portion having a larger area than the area of the central portion may be used for light sources emitting light with a relatively narrow light beam.
  • the convex shape of the peripheral portion may be adapted to converge light exiting through the peripheral portion.
  • Light reaching the peripheral portion may hence be redirected towards a predetermined angle of divergence relative to the optical axis, wherein the predetermined angle may be selected based on the angle of divergence of the central portion in order to achieve a smooth transition in intensity distribution between light exited through the central portion and light exited through the peripheral portion.
  • the profile or shape of the light-exiting surface may be described by the shape of a curve indicating the outline of the body in a cross section taken along a plane that includes the optical axis.
  • the at least one tooth of the central portion may be represented by a saw tooth curve (comprising at least one saw tooth), flanked on both sides by a curve forming parts of a negative parabola
  • the curve may be symmetric with respect to the optical axis.
  • the shape of the body of the optical lens may be described by a rotation of the curve around the optical axis.
  • the present embodiments are not limited to any specific symmetries.
  • the edge surface may extend in a plane essentially parallel to the optical axis, i.e. form a vertical step in the light-exiting surface, which may reduce the amount of light passing through the edge surface and thereby provide a more optically efficient lens.
  • the edge surface may extend in a plane intersecting the light source, i.e. have an extension along a direction of light emitted from the light source, so as to further reduce the amount of light passing through the edge surface.
  • the light source is arranged in e.g. a cavity or recess of the body, having a wall or interface at which light may be refracted
  • the edge surface may extend in a plane parallel to a path of the light refracted at said wall or interface.
  • the at least one tooth may extend around the optical axis to form a circle or oval.
  • the tooth may e.g. form part of a Fresnel lens wherein the rings or teeth extend concentrically around the optical axis.
  • the peripheral portion may extend in a circle or oval around the optical axis.
  • the peripheral portion may comprise one or several teeth, such as a Fresnel structure.
  • the optical lens is a peanut lens.
  • a peanut lens should be understood as an optical lens having a bilobed shape wherein the body is provided with a waist or transversely narrowed portion in the middle, as seen along the optical axis.
  • a peanut lens may advantageously be used for providing output light in the form of essentially two light beams, such as two focused light beams, which may be directed along e.g. a road with a relatively smooth intensity transition between them.
  • the optical lens may be formed in a single piece or by several separate pieces.
  • the optical lens may e.g. comprise an at least partly light-transmitting material such as glass, plastic, ceramics or a polymer.
  • the material may preferably be chosen so as to obtain a desired refraction index.
  • a relatively high refraction index may e.g. allow for the thickness of the optical lens to be reduced and/or for the leaning the main surface of the tooth to be reduced relative to the optical axis.
  • the optical lens may e.g. be formed by molding, including e.g. blow molding, compression molding, injection molding and matrix molding. Molding is advantageous in that it may be suitable for large-scale production. Once the tools, such as the molds, are provided, the optical lens can be mass-produced in relatively large volumes and at a relatively low cost. It will be appreciated that the main surface, and possibly the edge surface and/or the entire tooth, may be freeform to provide a prescribed or desired light intensity distribution.
  • the light source may be arranged in a void or recess in the body of the optical lens.
  • the optical lens may be molded directly on the light-source, which may be at least partly embedded in the body of the optical lens.
  • the term "light source” is used to define substantially any device or element that is capable of emitting radiation in any region or combination of regions of the electromagnetic spectrum, for example the visible region, the infrared region, and/or the ultraviolet region, when activated e.g. by applying a potential difference across it or passing a current through it.
  • Examples of light sources include semiconductor, organic, or polymer/polymeric light-emitting diodes (LEDs), blue LEDs, optically pumped phosphor coated LEDs, optically pumped nano-crystal LEDs or any other similar devices as known to a person skilled in the art.
  • the light source may be provided on a support, such as a substrate, such that an electrical connection is provided between the substrate and the light source.
  • the light source may be arranged on or coupled to the substrate so as to be able to emit light generally into the light-transmitting body of the optical lens and towards the light-exiting surface.
  • the optical lens may be sealingly coupled to the substrate to enclose the light source, or provide a hermetic or gastight sealing of the light source, so as to protect the light source from the ambient environment. Further, the optical lens may comprise a cavity or recess at least partly filled with a dielectric, such as e.g. soft silicone, to surround or protect the light source. It is noted that embodiments of the invention relates to all possible
  • Fig. 1 is a cross-sectional side view of a lighting device comprising an optical element according to an embodiment
  • Fig. 2 is a top view of the lighting device of Fig. 1, and
  • Fig. 3 is a perspective view of the lighting device of Fig. 1.
  • the lighting device 10 comprises a light source 110 that may be arranged in the light-transmitting body 120 of an optical lens 100, or arranged external to the optical lens 100 and such that light is emitted into the optical lens 100.
  • the light source 110 may e.g. comprise a solid state light source, such as e.g. a light-emitting diode (LED).
  • the optical lens 100 may e.g. be molded directly onto or around the light source 110, or provided with a recess or void configured to receive the light source 110. It will also be appreciated that the optical lens 100 may be snapped onto the light source 110 in a releasable or non-releasable manner.
  • the light source 110 may be arranged along an optical axis O of the optical lens 100, and preferably at a side of the optical lens 100 arranged opposite to a light-exiting surface 130 of the optical lens 100.
  • the optical lens 100 may be formed of an at least partly light-transmitting body 120 that is adapted to receive and transmit light emitted from the light source 110.
  • An outer surface of the light-transmitting body 120 may form a light-exiting surface 130 through which transmitted light may exit the optical lens 100.
  • the light-exiting surface 130 may be arranged to define an outer periphery of the light-transmitting body 120.
  • the optical lens 120 may comprise a portion that is not optically active, for instance for mechanical reasons like connecting the optical lens 120 to a carrier.
  • the light-transmitting body 120 may comprise a peripheral portion 131 and a central portion 132 relative to the optical axis O, wherein the peripheral portion 131 is convex relative to the light-transmitting body 120 and wherein the central portion 132 comprises a plurality of teeth 140 that may protrude from the body 120.
  • Each tooth 140 may be formed by a main surface 141 and an edge surface 142, wherein the edge surface 142 may form a vertical step in the direction of the optical axis O.
  • the main surface 141 may be slightly inclined inwards, towards the optical axis O.
  • the main surface 141 and the edge surface 142 of each tooth 140 may, according to the present embodiment, intersect to form an edge or tip that protrudes from the light-transmitting body 120 of the optical lens 100, thus forming a protruding tooth 130.
  • the main surface 141 is larger than the edge surface 142 and is adapted to allow more light to pass through the main surface 141 than the edge surface 142.
  • the main surface 141 and the edge surface 142 may be arranged to define the outer periphery or boundary of the respective tooth 140, which may have a lateral extension in a plane intersecting the optical axis O. Further, the tooth 140 may extend in a closed loop encircling the optical axis O, which will be discussed in more detail with reference to figure 2.
  • light may be emitted by the light source 110 and transmitted through the light-transmitting body 120 towards the light-exiting surface 130.
  • a main surface 141 that is tilted or inclined towards the optical axis O By using a main surface 141 that is tilted or inclined towards the optical axis O, light exiting the main surface 141 may be directed or diverged away from the optical axis O.
  • Light emitted from the light source 110 in a forward direction i.e. in a direction along the optical axis O, may hence be diverged as it exits the central portion of the light-transmitting body 120.
  • the lighting device 10 may comprise a LED 110 having a Lambertian intensity distribution that is relatively concentrated around the optical axis O.
  • the central portion 132 of the light-exiting surface 130 may then diverge the light beam in an off-axis direction so as to mitigate the relatively narrow intensity distribution of light generated by the LED 110.
  • the main surface 141 of the teeth 140 may be flat. It will however be appreciated that the main surface 141 and/or the edge surface 142 may have other shapes as well, such as being concave or convex.
  • the central portion 132 of the light-exiting surface 130 may comprise a plurality of teeth 140 forming a Fresnel lens structure adapted to redirect light exiting the central portion 132 in a desired direction, and preferably in an off-axis direction relative to the optical axis O.
  • Figures 2 and 3 illustrate a top view and a perspective view, respectively, of a lighting device 10 similarly configured as the lighting device described with reference to figure 1.
  • the lighting device 10 comprises a light source 110 and an optical lens 100 arranged to transmit and exit light emitted by the light source 110.
  • the central portion 132 of the light-exiting surface 130 of the light-transmitting body 120 comprises several teeth 140 extending in a plane intersecting the optical axis O and enclosing the optical axis O, thereby forming a Fresnel-type lens structure.
  • the peripheral portion 131, surrounding the central portion 132 may form a convex portion of the light-exiting surface 130 that is smoother than the central portion 132.
  • the optical lens 100 may be formed as a peanut lens, i.e. a bilobed shape having a waist or transversely narrowed portion in the middle, near the optical axis O, when viewed from above as in figure 2.
  • an outer contour or footprint of the light- transmitting body 120 or optical lens 100 as projected on a plane perpendicular to the optical axis O, shows that the footprint is elongated in the direction of the peripheral portion 131.
  • This footprint may be formed such that a distance between the outer contour and the optical axis O is shorter at the central portion 132 than at the peripheral portion 131.
  • the teeth 140 may be concentrically arranged around the optical axis O in e.g. circles or ovals on or in the central portion 132.
  • the light-source 110 of the lighting device 10 as described with reference to figures 1 and 2 may be arranged on a support structure, such as a printed circuit board (not shown), which may be adapted to provide the light source 110 with electrical power.
  • the support structure may further comprise fasteners (not shown) for attaching or sealing the optical lens 100 in position over the light source 110.
  • the optical lens 100 may be molded directly on the support structure.
  • a lighting device 10 and an optical lens 100 are provided, wherein the optical lens 100 comprises a light-exiting surface 130 having a convex peripheral portion 131 and a central portion 132 comprising at least one tooth 140 extending at least partly around the optical axis O of the optical lens.
  • the tooth may e.g. form part of a Fresnel lens and may be adapted to redirect light exiting through a main surface 141 of the tooth 140 away from the optical axis O, thereby allowing for a more evenly distributed intensity of light emitted through the optical lens.
  • the central portion may comprise a plurality of mutually different teeth, convex and/or concave portions.
  • the peripheral portion may be provided with additional structures, such as e.g. one or several teeth, arranged to provide a desired optical effect.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

L'invention concerne une lentille optique (100), apte à transmettre de la lumière depuis une source de lumière (110). La lentille optique (100) comprend un corps de transmission de lumière (120) et une surface de sortie de lumière (130) depuis laquelle la lumière est délivrée depuis la lentille (100). La surface de sortie de lumière (130) est disposée sur le corps (120) et comprend une portion périphérique (131) et une portion centrale par rapport à un axe optique de la lentille (100). La portion périphérique (131) est une portion convexe. La portion centrale (131) comprend au moins une dent (140) qui est formée par une surface principale (141) et une surface de bord (142), la surface principale (141) penchant vers l'axe optique. En outre, la dent (140) s'étend au moins partiellement autour de l'axe optique. La présente invention concerne une lentille optique (100) apte à atténuer une répartition d'intensité relativement étroite de la lumière émise par la source de lumière (110).
PCT/EP2016/068874 2015-08-21 2016-08-08 Lentille optique avec structure de dent Ceased WO2017032585A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP15181908 2015-08-21
EP15181908.3 2015-08-21

Publications (1)

Publication Number Publication Date
WO2017032585A1 true WO2017032585A1 (fr) 2017-03-02

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ID=54007541

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2016/068874 Ceased WO2017032585A1 (fr) 2015-08-21 2016-08-08 Lentille optique avec structure de dent

Country Status (1)

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WO (1) WO2017032585A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008122941A1 (fr) * 2007-04-05 2008-10-16 Koninklijke Philips Electronics N.V. Dispositif de mise en forme de faisceaux lumineux
US20100027271A1 (en) * 2008-08-01 2010-02-04 Ruud Lighting, Inc. Light-directing lensing member with improved angled light distribution
EP2426521A2 (fr) * 2010-09-06 2012-03-07 Samsung LED Co., Ltd. Lentille optique et module de source lumineuse et lampadaire en disposant
US20130320843A1 (en) * 2012-05-29 2013-12-05 Maxemil Photonics Corporation Lighting device and light control component thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008122941A1 (fr) * 2007-04-05 2008-10-16 Koninklijke Philips Electronics N.V. Dispositif de mise en forme de faisceaux lumineux
US20100027271A1 (en) * 2008-08-01 2010-02-04 Ruud Lighting, Inc. Light-directing lensing member with improved angled light distribution
EP2426521A2 (fr) * 2010-09-06 2012-03-07 Samsung LED Co., Ltd. Lentille optique et module de source lumineuse et lampadaire en disposant
US20130320843A1 (en) * 2012-05-29 2013-12-05 Maxemil Photonics Corporation Lighting device and light control component thereof

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