WO2009001272A1 - Dispositif d'émission de lumière équipé d'un guide de lumière en forme de cône tronqué - Google Patents

Dispositif d'émission de lumière équipé d'un guide de lumière en forme de cône tronqué Download PDF

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Publication number
WO2009001272A1
WO2009001272A1 PCT/IB2008/052462 IB2008052462W WO2009001272A1 WO 2009001272 A1 WO2009001272 A1 WO 2009001272A1 IB 2008052462 W IB2008052462 W IB 2008052462W WO 2009001272 A1 WO2009001272 A1 WO 2009001272A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
light guide
output device
guide
light source
Prior art date
Application number
PCT/IB2008/052462
Other languages
English (en)
Inventor
Erik Boonekamp
Johannes P. M. Ansems
Original Assignee
Koninklijke Philips Electronics N.V.
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 Koninklijke Philips Electronics N.V. filed Critical Koninklijke Philips Electronics N.V.
Publication of WO2009001272A1 publication Critical patent/WO2009001272A1/fr

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
    • F21V7/00—Reflectors for light sources
    • F21V7/0091—Reflectors for light sources using total internal reflection
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
    • F21K9/61—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction using light guides
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • 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]
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0045—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide
    • G02B6/0046—Tapered light guide, e.g. wedge-shaped light guide

Definitions

  • the present invention relates to a light output device comprising a light source and a light guide for guiding light from the light source, the light guide having a concave inner side and an outer side tapered to each other.
  • the invention also relates to a light guide suitable for use in such light output device.
  • the invention further relates to a luminaire provided with at least one such light guide.
  • LEDs light emitting diodes
  • CPC complex optical element
  • US-A 7,181,378 discloses a refraction, reflection, internal reflection and refraction (RXIR) apparatus having a lens surrounding a LED.
  • the lens has an upper surface comprising a reflectively coated central zone surrounded by a totally internally reflecting peripheral surface and extending to a mounting flange.
  • the lower surface comprises a central cavity with an entry-surface and a surrounding reflective surface, such as a reflectively coated surface and/or a total internal reflection (TIR) surface.
  • Rays propagate outward from a focal point to enter the lens through the entry surface, to be reflected by the upper surface to a reflector to be again reflected, then out the lens through the upper surface.
  • TIR total internal reflection
  • the present invention provides a light output device comprising a light source and a light guide for guiding light from the light source, the light guide having a concave inner side and an outer side tapered to each other, wherein the light guide is arranged to couple the light out of the light guide over an area of the inner side of the light guide after at least two total internal reflections on the inner side and/or the outer side of the light guide.
  • a portion of the light coupled into the light guide will alternately be reflected by these two sides by total internal reflection.
  • the light coupled into the light guide is viewed as a bundle of light rays in the form of a cone.
  • the cross section of the cone will increase as the light travels through the light guide.
  • the cross section of the cone becomes larger, the light rays are distributed over a larger area, lowering the peak brightness.
  • the number of times that the light experiences total- internal reflection before being coupled out of the light guide depends among others on the angle between the inner side and the outer side, the positioning of the light source with respect to the light guide, intensity distribution of the source, arrangement of the source(s) and the refractive indices of the light guide and the medium outside of the light guide. These parameters can be adjusted such that two or more total internal reflections occur for a large portion of the light coupled into the light guide.
  • the peak brightness of the light coupled in will be significantly decreased when the light is coupled out. In this way an improved visual comfort of the luminaire is obtained.
  • the light guide of the light output device is rotation symmetrical.
  • the light guide of the light output device may also have an elliptical shape or a polygonal shape such as a hexagonal shape, an octagonal shape, or similar shapes.
  • the light guide may have a shape formed by rotating a wedge type geometry over a central axis. Also the wedge surfaces can have a slight curvature to fine tune the intensity distribution.
  • the light output device further comprises an optical body surrounded by the inner side of the light guide, the optical body having a refractive index lower than a refractive index at the inner side of the light guide.
  • the outer side is covered by a reflecting surface.
  • the light coupled out from the outer side is reflected towards inner side. This results in that all light will leave the light output device from the inner side of the light guide.
  • the light guide comprises a base side arranged for coupling the light into the light guide.
  • a phosphor layer is arranged on the base side.
  • the phosphor layer may comprise e.g. YAG:Ce or a mixture of various phosphors.
  • the phosphor layer converts the light from the light source into light of different wavelengths.
  • the phosphor may be coated on a sheet and the sheet may be arranged on the base side.
  • the light source is mounted to a light source mounting element provided at a mounting part of the device, the light source being surrounded by the base side.
  • the mounting part of the device may be the rim of the base side.
  • the light source mounting element may be a plate which partly or wholly covers the space surrounded by the base side. This provides an alternative form of the light output device in which the light source is not directly mounted on the base side.
  • the light coupled out from the light guide is emitted through a light emitting window defined by a free rim of the light guide.
  • the device comprises a shielding element in the center of the light guide having a reflecting or absorbing surface for preventing the light from the light source from being directly emitted through the light emitting window.
  • a shielding element in the center of the light guide having a reflecting or absorbing surface for preventing the light from the light source from being directly emitted through the light emitting window.
  • the inner side and the outer side are tapered to each other in the direction from the base side to the free rim.
  • the outer side is tapered in the direction from the free rim to the base side. This allows the light to be emitted through the light emitting window which is larger than the base side where the light was coupled in.
  • the light source comprises one or more LEDs.
  • the light source may comprise a single LED (e.g. white or monochromatic) or several LEDs (e.g. R, G, B or R, G, B, A). LEDs are beneficial from many points of view, for instance power efficiency and long lifetime.
  • LEDs other appropriate light sources could be used, such as other semiconductor light sources (e.g. laser diodes).
  • a phosphor layer is arranged on the base side, the phosphor converts part of the light from one or more blue LEDs into yellow light. The combination yields white light.
  • a light guide is provided suitable for use in the light output device according to the invention.
  • a luminaire housing comprising at least one light source mounting element and at least one light guide for guiding light from the light source, the light guide having a concave inner side and an outer side tapered to each other, wherein the light guide is arranged to couple the light out of the light guide over an area of the inner side of the light guide after at least two total internal reflections on the inner side and/or the outer side of the light guide.
  • a luminaire comprising a luminaire housing according to the invention and at least one light source.
  • Figure Ia schematically illustrates a cross section of an embodiment of the light output device according to the invention
  • Figure Ib shows rotation of a wedge-shaped geometry which constitutes an embodiment of the light guide according to the invention
  • Figure 2 is an angle distribution of the light coupled out of an embodiment of the light output device according to the invention
  • Figure 3 is a schematic diagram of the reflection of light in an embodiment of the light guide according to the invention
  • Figure 4 schematically illustrates a cross section of a further embodiment of the light output device according to the invention.
  • Figure 5 schematically illustrates a cross section of a further embodiment of the light output device according to the invention.
  • Figure 6 schematically illustrates a cross section of an embodiment of the luminaire housing according to the invention.
  • a light output device 100 comprising a light source 101 and a light guide 102.
  • the light guide 102 has a rotation symmetrical form, which is formed by rotating a wedge-type geometry over a central axis Z as illustrated in figure Ib.
  • the wedge can be described by the parameters (length a, length b, distance x, angle ⁇ ) as indicated in this figure.
  • the total height H of the construction is described by
  • the light guide 102 comprises an inner side 103, an outer side 104, a base side 105 and a free rim 106. Since the light guide 102 is formed by rotating a wedge-type geometry over a central axis, the inner side 103 has a rotation symmetrical concave shape (truncated cone shape). The inner and the outer sides 103, 104 are tapered to each other in the direction from the base side 105 to the free rim 106 of the light guide where the two sides join and make an angle ⁇ .
  • the free rim 106 defines a light emitting window 107 from which the light is emitted.
  • the outer side 104 is tapered in the direction from the free rim 106 to the base side 105.
  • the outer side 104 of the light guide 102 is covered by a mirror 108.
  • the mirror 108 may be made from silver composition known per se.
  • the space, being a cavity, surrounded by the inner side 103 and the light emitting window 107 is at least partly filled with an optical body 109 having a refractive index lower than a refractive index at the inner side 103 of the light guide 102.
  • the light source 101 is provided on a phosphor layer 112 arranged on the base side 105 of the light guide 102.
  • the phosphor layer 112 is optional and that the light source 101 may be directly provided on the base side 105.
  • the light source 101 comprises a plurality of LEDs 101 which emit lights of different colors, e.g., red, green and blue.
  • the phosphor layer 112 may comprise e.g. YAG:Ce or a mixture of various phosphors. With this arrangement, the phosphor layer 112 converts part of the light from blue LEDs into yellow light. The combination of the yellow light and the non- converted blue light yields white light.
  • the light guide 102 may be made of polymethylmethacrylate (PMMA), polycarbonate, glass or similar materials.
  • the light from the light source 101 is emitted in the light guide 102 between the inner and the outer sides 103, 104.
  • the light transmitting in the light guide 102 will alternately be reflected on the inner and outer sides 103, 104. Through reflections, the angle at which the light is incident on the inner side 103 relative to the normal of the inner side 103 will eventually become lower than the critical angle of total internal reflection, and the light will be coupled out of the inner side 103.
  • the light will be coupled out over an area of the inner side 103, to be emitted through the light emission window 107.
  • Figure 2 shows an angle distribution of the light coupled out of an exemplary light output device according to the present invention.
  • three LEDs having a dimension of lmm 2 are located 2 mm from the central axis and are equally distributed around this axis. It will be appreciated that these dimensions and the arrangement of the LEDs are merely given as examples and the present invention is not limited to this embodiment.
  • the cut-off in the angle distribution is determined by the angle ⁇ .
  • FIG 3 a cross section of the light guide according to the invention is shown, in which light rays travel through the light guide between the inner side 103 and the outer side 104.
  • the light rays traveling in the light guide 102 are illustrated as a cone C of rays.
  • the figure shows the change in the area of cross section of the cone of the light rays through reflections.
  • the cone has light rays Al and Bl at the surface of the cone.
  • the ray Al incident on the inner side 103 will be reflected thereby and becomes a ray A2.
  • the ray A2 in turn will be reflected by the outer side 104 and becomes a ray A3.
  • the ray Bl incident on the inner side 103 will be reflected thereby to become B2, which in turn will be reflected by the outer side 104 to become B3.
  • the distance between the points where the rays A3 and B3 hit the inner side 103 will be larger than the rays Al and Bl hit the inner side 103.
  • the area of the cross-section of the cone of light rays is thus larger after reflections. This means that the light rays are incident on larger area, so the perceived brightness is decreased if the light rays are coupled out.
  • the light source is mounted to a light source mounting element 110 provided at a rim of the base side.
  • the light source mounting element seals the space surrounded by the base side.
  • the base side 105 of the light guide 102 extends to the center axis of the light guide. Substantially all the light from the light source will be coupled into the light guide through the base side.
  • the light source is mounted to a light source mounting element 110 provided at a rim of the bottom side, similarly to figure 4.
  • the base side 105 of the light guide 102 does not extend to the center axis.
  • the light output device comprises a shielding element 111 in its center having a reflecting surface. Substantially all the light from the light source will be coupled into the light guide through the base side.
  • the shielding element 111 prevents direct light from the light source 101 without experiencing reflections between the inner and the outer sides 103, 104. It is thus prevented that the light from the light source 101 is directly emitted through the light emitting window 107.
  • the shielding element 111 may alternatively have an absorbing surface.
  • Figure 6 shows a luminaire housing 200 comprising a plurality of light source mounting element 110 and a plurality of light guide 102.
  • the light guide 102 has a concave inner side 103 and an outer side 104 tapered to each other.
  • the light guide 102 is arranged to couple the light out of the light guide 102 over an area of the inner side 103 of the light guide 102 after at least two total internal reflections on the inner side 103 and/or the outer side 104 of the light guide 102.
  • any reference signs placed between parentheses shall not be construed as limiting the claim.
  • Use of the verb "comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim.
  • the article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements.
  • 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.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • General Physics & Mathematics (AREA)
  • Planar Illumination Modules (AREA)

Abstract

L'invention concerne un dispositif d'émission de lumière (100) qui comprend une source de lumière (101) et un guide de lumière (102) destiné à guider la lumière en provenance de la source de lumière, le guide de lumière possédant un côté intérieur concave (103) et un côté extérieur (104), lesdits côtés allant en se rapprochant l'un de l'autre, le guide de lumière étant agencé pour extraire par couplage la lumière en provenance du guide de lumière sur une surface du côté intérieur du guide de lumière, après au moins deux réflexions internes totales sur le côté intérieur et/ou le côté extérieur du guide de lumière. L'invention se rapporte aussi à un dispositif d'émission de lumière dans lequel la luminance de crête perçue de la lumière extraite par couplage est réduite.
PCT/IB2008/052462 2007-06-27 2008-06-23 Dispositif d'émission de lumière équipé d'un guide de lumière en forme de cône tronqué WO2009001272A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP07111140 2007-06-27
EP07111140.5 2007-06-27

Publications (1)

Publication Number Publication Date
WO2009001272A1 true WO2009001272A1 (fr) 2008-12-31

Family

ID=39884558

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2008/052462 WO2009001272A1 (fr) 2007-06-27 2008-06-23 Dispositif d'émission de lumière équipé d'un guide de lumière en forme de cône tronqué

Country Status (2)

Country Link
TW (1) TW200918829A (fr)
WO (1) WO2009001272A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2444720A1 (fr) * 2010-10-23 2012-04-25 Automotive Lighting Reutlingen GmbH Dispositif d'éclairage pour un véhicule automobile
WO2013095959A1 (fr) * 2011-12-20 2013-06-27 3M Innovative Properties Company Guide de lumière servant de luminaire
WO2013141053A1 (fr) * 2012-03-22 2013-09-26 シャープ株式会社 Dispositif d'éclairage, phare de véhicule, et élément de guidage de lumière
CN105180096A (zh) * 2013-05-03 2015-12-23 瑞仪光电股份有限公司 可控制光型的导光组件及灯具
CN105229372A (zh) * 2013-05-16 2016-01-06 3M创新有限公司 作为照明设备的光导
US9599310B2 (en) 2013-05-03 2017-03-21 Radiant Opto-Electronics Corporation Light guide element for controlling light distribution and lamp
DE102014119516B4 (de) * 2014-12-23 2018-12-06 Iventum Gmbh Reflektorkörper für Lampen
EP3477768A1 (fr) * 2017-10-24 2019-05-01 Dayu Optoelectronics Co., Ltd. Ensemble d'émission de lumière de véhicule

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5555161A (en) * 1995-09-11 1996-09-10 Delco Electronics Corporation Bi-functional light pipe and display assembly
JP2002245830A (ja) * 2001-02-14 2002-08-30 Asahi Matsushita Electric Works Ltd 導光板装置
DE20206829U1 (de) * 2002-04-30 2002-09-05 Automotive Lighting Reutlingen GmbH, 72762 Reutlingen Leuchte, insbesondere Begrenzungsleuchte
EP1600908A2 (fr) * 2004-05-29 2005-11-30 FER Fahrzeugelektrik GmbH Corps optique
EP1617247A2 (fr) * 2004-07-14 2006-01-18 Federal Signal Vama, S.A. Lentille de collimation à reflexion totale interne
US20060126343A1 (en) * 2004-12-15 2006-06-15 Min-Hsun Hsieh LED light source
US7181378B2 (en) * 2002-10-11 2007-02-20 Light Prescriptions Innovators, Llc Compact folded-optics illumination lens

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5555161A (en) * 1995-09-11 1996-09-10 Delco Electronics Corporation Bi-functional light pipe and display assembly
JP2002245830A (ja) * 2001-02-14 2002-08-30 Asahi Matsushita Electric Works Ltd 導光板装置
DE20206829U1 (de) * 2002-04-30 2002-09-05 Automotive Lighting Reutlingen GmbH, 72762 Reutlingen Leuchte, insbesondere Begrenzungsleuchte
US7181378B2 (en) * 2002-10-11 2007-02-20 Light Prescriptions Innovators, Llc Compact folded-optics illumination lens
EP1600908A2 (fr) * 2004-05-29 2005-11-30 FER Fahrzeugelektrik GmbH Corps optique
EP1617247A2 (fr) * 2004-07-14 2006-01-18 Federal Signal Vama, S.A. Lentille de collimation à reflexion totale interne
US20060126343A1 (en) * 2004-12-15 2006-06-15 Min-Hsun Hsieh LED light source

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2444720A1 (fr) * 2010-10-23 2012-04-25 Automotive Lighting Reutlingen GmbH Dispositif d'éclairage pour un véhicule automobile
WO2013095959A1 (fr) * 2011-12-20 2013-06-27 3M Innovative Properties Company Guide de lumière servant de luminaire
WO2013141053A1 (fr) * 2012-03-22 2013-09-26 シャープ株式会社 Dispositif d'éclairage, phare de véhicule, et élément de guidage de lumière
CN105180096A (zh) * 2013-05-03 2015-12-23 瑞仪光电股份有限公司 可控制光型的导光组件及灯具
US9599310B2 (en) 2013-05-03 2017-03-21 Radiant Opto-Electronics Corporation Light guide element for controlling light distribution and lamp
CN105229372A (zh) * 2013-05-16 2016-01-06 3M创新有限公司 作为照明设备的光导
EP2997301A4 (fr) * 2013-05-16 2017-04-19 3M Innovative Properties Company Conduit de lumière servant de luminaire
US10036517B2 (en) 2013-05-16 2018-07-31 3M Innovative Properties Company Lightguide as luminaire
DE102014119516B4 (de) * 2014-12-23 2018-12-06 Iventum Gmbh Reflektorkörper für Lampen
EP3477768A1 (fr) * 2017-10-24 2019-05-01 Dayu Optoelectronics Co., Ltd. Ensemble d'émission de lumière de véhicule

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