WO2008032277A2 - Flat and thin led-based luminary providing collimated light - Google Patents
Flat and thin led-based luminary providing collimated light Download PDFInfo
- Publication number
- WO2008032277A2 WO2008032277A2 PCT/IB2007/053681 IB2007053681W WO2008032277A2 WO 2008032277 A2 WO2008032277 A2 WO 2008032277A2 IB 2007053681 W IB2007053681 W IB 2007053681W WO 2008032277 A2 WO2008032277 A2 WO 2008032277A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- light
- light emitting
- emitting device
- guide plate
- protrusions
- Prior art date
Links
Classifications
-
- 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
- G02B6/0066—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 characterised by the light source being coupled to the light guide
- G02B6/0068—Arrangements of plural sources, e.g. multi-colour light sources
-
- 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
- G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
- G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
- G02B6/0028—Light guide, e.g. taper
-
- 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
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
- G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
-
- 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
- G02B6/0066—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 characterised by the light source being coupled to the light guide
- G02B6/0073—Light emitting diode [LED]
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
- F21W2131/00—Use or application of lighting devices or systems not provided for in codes F21W2102/00-F21W2121/00
- F21W2131/40—Lighting for industrial, commercial, recreational or military use
- F21W2131/402—Lighting for industrial, commercial, recreational or military use for working places
Definitions
- the present invention relates to a light-emitting device comprising a plurality of mutually spaced apart light emitting diodes arranged on a substrate, and a light guide plate.
- luminaries should fulfill several requirements. Firstly, the light source should have a sufficiently long lifetime. Conventional luminaries are often based on fluorescent tubes, which have a relatively limited lifetime. In a typical office environment, the tubes themselves needs to be replaced every 6000 hours. This corresponds to a replacement every 2 years, which adds to the cost of ownership.
- the light output of the luminary should be robust against dust and other dirt.
- a luminary that collects dust will become less efficient, since the dirt blocks light. Since cleaning the luminary is an expensive matter, the design should be robust against dust and dirt.
- the luminary should satisfy an anti-glare requirement, (the unified glare ratio should be sufficiently small).
- This anti-glare requirement means that the luminary should not show any bright spots. In particular, there should be no bright spots if the luminary is viewed under an oblique angle.
- a luminary of the prior art is disclosed in US 6 241 358, describing a lighting panel consisting of a set of light guide blocks in tandem arrangement, where a separate fluorescent tube provide light for each light guide block. The light from the fluorescent tubes is transmitted into the respective light guide block, is distributed therein and is transmitted through an output surface of the light guide block.
- fluorescent tubes have a limited lifetime and are expensive to replace. Further, the breakdown of a single fluorescent tube in this prior art luminary has a drastic negative impact on the lighting capacity of the lighting panel and on the homogeneity of the light from the lighting panel. Thus, when one of the tubes breaks down, it will be necessary to replace this broken tube immediately. Further, fluorescent tubes emit a constant spectrum, which limits the color variability capacity of such a lighting panel.
- a further object of the present invention is to provide a light-emitting device that provides light that is well collimated.
- the present invention provides a light emitting device, comprising a plurality of light emitting diodes arranged mutually spaced apart on a substrate, said light emitting diodes being arranged to emit light in a general direction along the surface of said substrate.
- the light emitting device comprises a light guide plate of a translucent material having a back surface facing said substrate and an opposing front surface, said back surface comprising a first array of protrusions extending towards said substrate, said protrusions providing a light receiving face arranged to transmit light from light emitting diodes into said light guide plate and a light reflection face arranged to reflect light in said light guide plate, having a directional component along said general direction of light, towards said front side.
- collimators are arranged in the light path between said light emitting diodes and said light receiving faces.
- the collimators are typically funnel-shaped.
- the light from the plurality of LEDs will be transmitted in to the light guide plate and will be distributed therein before exiting the light guide plate via the front side thereof.
- the present invention provides a light-emitting device that provides well- distributed light from a plurality of point light sources.
- light emitting diodes are advantageous as they have a long lifetime. Hence, service intervals will be extended, leading to a lower cost of ownership. Further, light emitting diodes are capable of emitting light of saturated colors, allowing the light-emitting device to produce light with high color- variability.
- the collimators collimate the light emitted by said light emitting diodes in a direction along the surface of said substrate and perpendicular to the general direction of light emitted by the light emitting diodes. Due to its design, the light guide plate will act as a collimator such that light exiting the light guide plate will be collimated in the direction along the first array of protrusions.
- the light guide plate will essentially not provide any collimation of light in the direction perpendicular to the direction along the first array or protrusions.
- collimators such that the light entering the light guide plate is collimated in the direction, along the surface of said substrate and perpendicular to the general direction of light emitted by the light emitting diodes, the light exiting the light guide plate will be collimated in the direction perpendicular to the direction along the first array or protrusions.
- a reflective layer may be arranged between collimators and the light guide plate, such that light exiting the light guide plate via the back surface can be reflected back towards the front surface of the light guide plate, thus increasing the light utilization efficiency of the device.
- another reflective layer may be arranged between collimators and the substrate in order to prevent light from exiting the collimator towards the substrate, and to prevent that scattered light from light emitting diodes enters the collimator through a surface thereof not intended for receiving light.
- reflective layers may be arranged at the back surface side of the reflection face of said protrusions of the first array.
- Such reflective layer increases the light utilization efficiency, since light exiting the light guide plate via the reflection faces can be reflected back towards the front surface. Further, it prevents light to be transmitted into the light guide plate via the reflection faces.
- more than one light emitting diode may provide light to a single light receiving face of a protrusion.
- a plurality of LEDs arranged to provide light to a single light receiving face may together form an extended light source, that will not fully be dysfunctional in the case one or a few of the LEDS in that plurality of LEDs break down, since the neighboring LEDs will still be in operation.
- a plurality of LEDs of different colors may provide light to a single receiving face in order to provide a color variable light-emitting device.
- the protrusions of said first array have triangularly shaped cross-section, preferably wherein the angle between the light receiving face and the front surface of the light guide plate is larger than the angle between the light reflecting face and the front surface.
- the substrate on which the light emitting diodes are arranged may comprises a plurality of mutually spaced apart recesses.
- a redirection sheet may be arranged at the front side of said light guide plate, where the redirection sheet has a prism- faced surface facing the front side of the light guide plate.
- Such a redirection sheet may be arranged in order to redirect the light exiting the light guide plate into a desired direction.
- Figure Ia illustrates, in cross-sectional view, an embodiment of a light- emitting device of the present invention.
- Figure Ib illustrates, in perspective view, the embodiment of figure Ia.
- Figure Ic illustrates an alternative design of the collimator shown in figure Ib.
- Figure 2 illustrates another embodiment of a light-emitting device of the present invention.
- Figure 3 illustrates yet another embodiment of a light emitting device of the present invention.
- a light emitting device 100 of one embodiment of the present invention is illustrated in figure Ia, and comprises an array of a plurality of light emitting diodes (LEDs) 107, arranged mutually spaced apart on a substrate 108.
- LEDs light emitting diodes
- the light emitting diodes 107 are arranged to emit light in essentially the same general direction L, essentially along the surface of the substrate 108, and in the direction of the array of the LEDs. LEDs capable of emitting light in a general direction essentially along the surface of the substrate that they are mounted on are especially suitable for use in the present invention. Examples of such diodes are those commonly known as side emitting diodes.
- the term "light emitting diode”, herein abbreviated "LED” refers however to any type of light emitting diode known to those skilled in the art, and encompasses, but is not limited to, inorganic based LEDs, organic based LEDs (OLEDs and polyLEDs) and laser diodes.
- the light-emitting device 100 further comprises a light guide plate 101 of a translucent material having a front surface 102 and an opposing back surface 103 facing the light emitting diodes 107.
- the light guide plate is arranged to receive light from the light emitting diodes via the back surface 103, to distribute the received light and to transmit the distributed light to the surroundings via the front surface 102.
- Suitable materials for use in the light guide plate 101 include translucent materials such as, but not limited to, polymeric materials, i.e. PMMA or polycarbonate, ceramic materials and glass materials.
- the back surface 103 of the light guide plate 101 presents a first array of protrusions 104 extending towards the substrate 108.
- the protrusions 104 are designed to have a light receiving face 105, through which face light from the light emitting diodes 107 enters into the light guide plate 101.
- the protrusions 104 also has a light reflection face 106, typically the alternate face of the protrusion, on which face light, that has been transmitted into the light guide 101, is reflected towards the front surface of the light guide plate.
- the light guide plate 101 is arranged such that the first array of protrusions 104 is aligned to the array of LEDs 107 on the substrate 108.
- the protrusions have a triangularly shaped cross-section, preferably as illustrated in figure Ia, being asymmetric such that the receiving face 105 has a steeper slope than the reflection face 106.
- the angle CC between the receiving face 105 and the front surface 102 of the light guide plate 101 is larger than the angle ⁇ between the reflection face 106 and the front surface 102.
- the angle CC is typically in the range of from 60 to 90°, and the angle ⁇ is typically in the range of from 1 to 15°.
- the pitch of the protrusions 104 of the light guide plate 101 i.e. the repetitive distance between adjacent protrusions, is typically in the range of from 1 to 30 mm, for example from about 10 to about 20 mm.
- light from the light emitting diodes 107 is transmitted into the light guide plate via the receiving faces 105 of the protrusions 104.
- the light will alternately encounter the front surface 102 of the light guide plate or a reflection face 106 of a protrusion.
- the light is transmitted out of the light guide plate 101, or is reflected back (total internal reflection) into the light guide plate, towards the back surface 103 where it will encounter a reflection face 106 for reflection again towards the front surface 102. Due to the angle between the front surface 102 and the reflection face 106, the incidence angle at this following encounter with the front surface 102 will be lower than the incidence angle at the preceding encounter, until the incidence angle eventually becomes lower than the critical angle for transmission out of the light guide.
- the reflection on the reflection faces 106 does at least partly depend on total internal reflection on theses surfaces.
- light will also be able to exit the light guide through the back surface 103 of the light guide plate, when the angle of incidence on the reflection faces 106 so allows.
- the reflection faces 106 may be provided with a reflective coating 109. Light transmitted out of the light guide plate via the reflection faces 106 will be reflected back towards the front surface of the light guide plate. This will enhance the light utilization efficiency of the device.
- Such reflective layer 109 may for example consist of a foil made of a reflecting material, and may be arranged between the reflection face 106 and the substrate 108, or between the reflection face 106 and a collimator 110, typically near the reflection face 106, or as a reflective coating on the back surface side of the reflection surface 106.
- the reflective layer 109 consists of a reflective foil positioned against the reflection face 106.
- collimators 110 are located in the light path between the light emitting diodes 107 and the corresponding receiving faces 105 to collimate the light before it enters the light guide plate 101.
- the collimators 110 are adapted to collimate the light in the direction along the surface of the substrate 108 and perpendicular to the general direction of light emitted by the light emitting diodes.
- the term "collimate” refer to the action of reducing the angular spread of light. Consequently, “collimator” refers to an optical element capable of receiving light from a light source and reducing the angular spread of the received light.
- the collimators 110 have the shape of a tapered funnel, so that the collimators have a gradually increasing cross-sectional area, with the smallest area at the side of the collimator receiving the light from the LED, the input side, and largest area, the output side, for transmitting the light out of the collimator and into the light receiving face 105 of the protrusion 104.
- the collimator 110 may have straight tapering sidewalls, but as illustrated in figure Ic, the collimator 110 may also have curved tapering sidewalls.
- a specific example of a collimator 110 having curved tapering sidewalls is commonly known as a compound parabolic concentrator (CPC) collimator, where the curvature of the sidewalls resembles the curvature of a parabola.
- CPC compound parabolic concentrator
- collimator having curved tapering sidewalls One advantage of using a collimator having curved tapering sidewalls is that the length of such a collimator may be reduced in comparison with a collimator having straight tapering sidewalls in order to achieve a specific collimation. Hence a more compact collimator may be obtained.
- other shapes of the collimator known to those skilled in the art may be used in the present invention to collimate the light before it enters the light guide plate.
- the collimators may be designed to also collimate the light in a direction along the normal of the substrate in order to provide light being well collimated in both directions orthogonal to the main direction of light (L).
- the sidewalls of the collimators 110 may be clear walls, where the reflection of light within the collimators relies on total internal reflection. However, at least some of the sidewalls (except for the input and output surfaces) may be non-transparent mirroring surfaces.
- a reflective layer 111 may optionally be arranged between the collimator 110 and the light guide plate, in order to prevent light from exiting the collimator towards the light guide plate elsewhere than through the intended output side of the collimator.
- a reflective layer 112 may optionally be arranged between the collimator 110 and the substrate in order to prevent light from exiting the collimator towards the substrate.
- the reflective layers 111 and 112 are typically reflective foils positioned against the respective surfaces of the collimator 110, or may alternatively be reflective coatings on the collimator.
- the reflective layer 111 may be may be a separate layer from, or may alternatively in fact be the reflective layer 109 descried above, such as a two-sided mirror.
- the array of protrusions 104 is an array of extended, mutually parallel protrusions, and where an array of more than one light emitting diode is arranged provide light to a single receiving face 105.
- the collimators 110 collimating the light from such an array of light emitting diodes may be separate collimators for each of the LEDs in the array, or may be an arrangement of several collimators joined together side by side to receive and collimate the light from several LEDs.
- the array of mutually spaced apart LEDs 107 may be an array of mutually spaced apart rows, where each row comprises multiple LEDs.
- the array of protrusions 104 may be an array of extended, mutually parallel protrusions, where a whole row, i.e. more than one light emitting diode, is located in a single space between two adjacent protrusions. Thus, more than one light emitting diode 107 provides light to the receiving face 105.
- the multiple LEDs 107 forming a row and providing light to a single receiving face 105 may act as a spatially extended, linear, light source. If one of these light emitting diodes in such a row incidentally break down, the impact on the overall performance of the light emitting device is only minor, since the neighboring light emitting diodes providing light to the same receiving face as the broken light emitting diode still are functioning. Further, light-emitting diodes of more than one color may be used to provide light to the same receiving face, in order to provide a color variable light-emitting device.
- the substrate 108 on which the LEDs are arranged comprises a plurality of recesses 209 between mutually spaced apart light emitting diodes 107.
- the plurality of recesses 209 in the substrate 108 is preferably aligned to the periodic nature of the light guide plate, i.e. to the array of protrusions 104. Hence, the distance between two adjacent such recesses 209 corresponds to the distance between two adjacent protrusions 104 of the light guide plate 101.
- portions of the collimators 110 may be located in the recesses 209. This improves and facilitates the alignment of the LEDs 107 with the receiving faces 105 of the protrusions 104 of the light guide plate.
- the light from a light-emitting device as illustrated in figures 1 and 2 will typically exit the light guide plate via the front surface 102 thereof into the surroundings at an noticeable angle with respect to the normal of the front surface 102.
- such a light-emitting device may be well suited for illuminating the ceiling when hung on a wall, or for illuminating a wall when arranged in the ceiling, but also for other purposes where light emission out of the normal of the front surface is desired.
- a redirection sheet 310 may be arranged at the front surface 102 to receive light that exits the light guide plate 101 via the front surface 102, in order to redirect the main direction of this light.
- An example of such a redirection sheet 310 comprises a sheet of a translucent material (i.e. plastic, ceramic or glass), which has a prismatic surface 311 facing the front surface 102 of the light guide plate.
- a translucent material i.e. plastic, ceramic or glass
- the prismatic surface 311 comprises a second array of mutually parallel protrusions 312.
- the protrusions 312 of the second array are advantageously essentially parallel to the protrusions 104 of the light guide plate 101.
- the protrusions 312 of the second array have a triangularly shaped cross-section with an apex angle in the range of from 20 to 70°.
- the protrusions 312 of the second array are typically formed at a pitch (distance between two adjacent protrusions) that are markedly lower than the pitch of the protrusions 104 of the first array.
- the pitch of the protrusions 312 of the second array is in the range of about 50 to 500 ⁇ m.
- the protrusions 312 of the second array may be symmetric or asymmetric with respect to the normal of the front surface 102 of the light guide plate, in the sense that the center line of the protrusions may be parallel (symmetric) or non-parallel (asymmetric) to the normal of the front surface 102.
- the centerline of a protrusion having a triangularly shaped cross-section is a thought line that divides the apex angle into to two equally large portions.
- ⁇ 0° refers to a symmetric protrusion
- ⁇ > 0° refers to an asymmetric protrusion tilted along the general direction of light emitted by the light emitting diodes
- ⁇ ⁇ 0° refers to an asymmetric protrusion tilted against the general direction of light emitted by the light emitting diodes.
- ⁇ > 0° refers to a protrusion tilted to the right
- ⁇ ⁇ 0° refers to a protrusion tilted to the left (as shown in Figure 3).
- the tilt angle ⁇ of the protrusions 312 of the second array is typically in the range of from -15° to 15°, and may be constant or may vary along the array.
- the apex and tilt angle of the protrusions 312 of the second array have been shown to affect the light exiting the redirection sheet into the surrounding.
- One effect of a redirection sheet 310 is that the exiting light is given a tendency to show a plurality of intensity peaks at different angles relative to the normal of the redirection sheet.
- apex angle value of about 40° At an apex angle value of about 40°, only one intensity peak appeared. Thus, in some embodiments of the present invention, about 40° represents a preferred apex angle, since a single intensity peak is achieved.
- tilt angle ⁇ of about 11° the light exits the redirection sheet 310 approximately parallel to the normal of the redirection sheet.
- a tilt angle ⁇ of about 11° is preferred since such a light-emitting device produces light perpendicular to the surface of the light-emitting device.
- a lower tilt angle for example 0°
- light exits the redirection sheet 310 at a negative angle to the normal of the redirection sheet.
- a higher tilt such as 15°
- the tilt angle ⁇ of the protrusions 312 of the second array varies along the extension of the second array in order to direct light from different portions of the device into different directions.
- the tilt angle ⁇ may decrease, for example from about 15° to -5°, such as from 11° to 0°, along the second array in the general direction of light emitted by the LEDs (i.e. if the LEDs are arranged to emit light generally to the right, the tilt angle ⁇ of the protrusions 312 of the second array is higher in a left portion of the second array then in a right portion of the array).
- This manner of varying the tilt angle will lead to a focusing of the light from the light-emitting device of the present invention.
- the redirection sheet 310 may be divided into two or more domains, where the tilt angle ⁇ of the protrusions 312 of the redirection sheet has a first value in a first such domain, and a second such value in a second domain. This may be used in order to achieve a light distribution with for example two intensity peaks at two different angles.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Planar Illumination Modules (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Non-Portable Lighting Devices Or Systems Thereof (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/377,564 US20100237359A1 (en) | 2006-09-15 | 2007-09-12 | Flat and thin led-based luminary providing collimated light |
JP2009527949A JP2010503960A (en) | 2006-09-15 | 2007-09-12 | Flat, thin, LED-based light emitter that provides collimated light |
EP07826358A EP2067181A2 (en) | 2006-09-15 | 2007-09-12 | Flat and thin led-based luminary providing collimated light |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP06120717.1 | 2006-09-15 | ||
EP06120717 | 2006-09-15 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2008032277A2 true WO2008032277A2 (en) | 2008-03-20 |
WO2008032277A3 WO2008032277A3 (en) | 2008-06-19 |
Family
ID=39111309
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2007/053681 WO2008032277A2 (en) | 2006-09-15 | 2007-09-12 | Flat and thin led-based luminary providing collimated light |
Country Status (5)
Country | Link |
---|---|
US (1) | US20100237359A1 (en) |
EP (1) | EP2067181A2 (en) |
JP (1) | JP2010503960A (en) |
CN (1) | CN101517754A (en) |
WO (1) | WO2008032277A2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008102297A1 (en) * | 2007-02-21 | 2008-08-28 | Koninklijke Philips Electronics N.V. | Lighting system with improved rigidity |
EP2280217A1 (en) * | 2009-07-28 | 2011-02-02 | LG Innotek Co., Ltd. | Light unit with light guide plate and display apparatus having the same |
US8292480B2 (en) | 2008-07-10 | 2012-10-23 | Koito Manufacturing Co., Ltd. | Lamp including main reflector, sub-reflector and LED assembly |
AU2010305933B2 (en) * | 2009-10-13 | 2015-07-16 | Centervue S.P.A | Lighting device for fundus cameras |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012056360A1 (en) * | 2010-10-28 | 2012-05-03 | Koninklijke Philips Electronics N.V. | Collimator comprising a prismatic layer stack, and lighting unit comprising such collimator |
KR101824036B1 (en) | 2011-06-30 | 2018-03-14 | 엘지이노텍 주식회사 | backlight unit and display apparatus using the same |
CN102914812A (en) * | 2011-08-04 | 2013-02-06 | 冠捷投资有限公司 | Light guide plate and backlight module |
KR102440140B1 (en) * | 2015-12-30 | 2022-09-06 | 엘지디스플레이 주식회사 | Viewing Angle Switchable Back Light Unit |
CA3071829A1 (en) | 2017-08-01 | 2019-02-07 | Technical Consumer Products, Inc. | Edge-lit light fixture having capabilities for a secondary service |
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US6130730A (en) * | 1996-02-14 | 2000-10-10 | Physical Optics Corporation | Backlight assembly for a display |
EP1670069A1 (en) * | 2003-09-29 | 2006-06-14 | Matsushita Electric Industrial Co., Ltd. | Linear light source and production method therefor and surface emission device |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
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JP3373427B2 (en) * | 1998-03-31 | 2003-02-04 | 日東樹脂工業株式会社 | Tandem type surface light source device |
JP2001312916A (en) * | 2000-02-24 | 2001-11-09 | Sony Corp | Surface light source device |
-
2007
- 2007-09-12 CN CNA2007800341837A patent/CN101517754A/en active Pending
- 2007-09-12 US US12/377,564 patent/US20100237359A1/en not_active Abandoned
- 2007-09-12 WO PCT/IB2007/053681 patent/WO2008032277A2/en active Application Filing
- 2007-09-12 EP EP07826358A patent/EP2067181A2/en not_active Withdrawn
- 2007-09-12 JP JP2009527949A patent/JP2010503960A/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6130730A (en) * | 1996-02-14 | 2000-10-10 | Physical Optics Corporation | Backlight assembly for a display |
EP1670069A1 (en) * | 2003-09-29 | 2006-06-14 | Matsushita Electric Industrial Co., Ltd. | Linear light source and production method therefor and surface emission device |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008102297A1 (en) * | 2007-02-21 | 2008-08-28 | Koninklijke Philips Electronics N.V. | Lighting system with improved rigidity |
US8292480B2 (en) | 2008-07-10 | 2012-10-23 | Koito Manufacturing Co., Ltd. | Lamp including main reflector, sub-reflector and LED assembly |
EP2280217A1 (en) * | 2009-07-28 | 2011-02-02 | LG Innotek Co., Ltd. | Light unit with light guide plate and display apparatus having the same |
US8662729B2 (en) | 2009-07-28 | 2014-03-04 | Lg Innotek Co., Ltd. | Light unit and display apparatus having the same |
AU2010305933B2 (en) * | 2009-10-13 | 2015-07-16 | Centervue S.P.A | Lighting device for fundus cameras |
Also Published As
Publication number | Publication date |
---|---|
EP2067181A2 (en) | 2009-06-10 |
CN101517754A (en) | 2009-08-26 |
JP2010503960A (en) | 2010-02-04 |
US20100237359A1 (en) | 2010-09-23 |
WO2008032277A3 (en) | 2008-06-19 |
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