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`US 20060285332Al
`
`c19) United States
`c12) Patent Application Publication
`Goon et al.
`
`c10) Pub. No.: US 2006/0285332 Al
`Dec. 21, 2006
`(43) Pub. Date:
`
`(54) COMPACT LED PACKAGE WITH REDUCED
`FIELD ANGLE
`
`(22) Filed:
`
`Jun. 15, 2005
`
`(76)
`
`Inventors: Wooi Kin Goon, Penang (MY); Thye
`Linn Mok, Penang (MY); Kee Yean
`Ng, Penang (MY); Bee Yin Janet
`Chua, Perak (MY); Gim Eng Chew,
`Penang (MY); Rene P. Helbing, Palo
`Alto, CA (US)
`
`Correspondence Address:
`AGILENT TECHNOLOGIES INC.
`INTELLECTUAL PROPERTY
`ADMINISTRATION, MIS DU404
`P.O. BOX 7599
`LOVELAND, CO 80537-0599 (US)
`
`(21) Appl. No.:
`
`111153,706
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`F21V 7100
`(2006.01)
`(52) U.S. Cl. ............................................ 362/327; 362/341
`
`(57)
`
`ABSTRACT
`
`A light emitting diode system includes a housing including
`a light emission opening and a light emitting diode disposed
`within the housing. A first film layer covers the light
`emission opening and includes a uniaxial collimating film
`configured to direct light from the light emitting diode along
`a first axis.
`
`208
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`IPR PAGE 1
`
`Acuity v. Lynk
`Acuity Ex.
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`1007
`
`

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`Patent Application Publication Dec. 21, 2006 Sheet 1 of 8
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`Patent Application Publication Dec. 21, 2006 Sheet 2 of 8
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`IPR PAGE 3
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`Patent Application Publication Dec. 21, 2006 Sheet 3 of 8
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`Patent Application Publication Dec. 21, 2006 Sheet 5 of 8
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`IPR PAGE 6
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`Patent Application Publication Dec. 21, 2006 Sheet 6 of 8
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`IPR PAGE 8
`
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`Diffusing the directed light with at least one of a liner and a light guide
`
`along a second axis offset from the first axis
`directing a second portion of light through the second polarization layer
`
`polarization layer along a first axis
`directing a first portion of the received light through a second
`
`receiving light in a first polarization layer
`
`1000
`
`FIG. 10
`
`receiving light in a first polarization layer
`
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`
`FIG. 9
`
`IPR PAGE 9
`
`

`
`US 2006/0285332 Al
`
`Dec. 21, 2006
`
`1
`
`COMPACT LED PACKAGE WITH REDUCED
`FIELD ANGLE
`
`BACKGROUND OF THE INVENTION
`
`[0001] Current Light Emitting Diode ("LED") packages
`have a general wide or narrow field of view ("FOY"). To
`achieve this currently, a lens is used to collimate the light
`from the light source/die. This normally adds additional
`height and area to the LED package. Current problems
`include an undesirable dome shape caused by an optical lens
`since a flat-sided and oblong shape is preferred for manu(cid:173)
`facturability and pick-and-place setups. Additionally, use of
`an optical lens adds height and size to the overall package
`thickness.
`
`[0002] FIGS. lA, lB, and lC illustrate prior art methods
`of collimating LED light. As shown in FIG. lA, LED light
`source 101 emits light beams 105 through lens 110. Simi(cid:173)
`larly, FIG. lB illustrates light source 101 emitting light
`beams 105 through another lens 110 and reflecting light
`beams 105 off reflector cup 115. Likewise, FIG. lC illus(cid:173)
`trates LED light source 101 emitting light beams 105
`through a lens 110 and reflected by reflector cup 115 and
`refracted by lens 110.
`[0003]
`Increased height and size are marked problems for
`big chip LED's, for example, a 1 watt LED of 0.9 mmx0.9
`mm, as big chip LED's require big lenses to collimate the
`emitted light for increased brightness. Increased brightness
`results from decreasing the FOY of the LED, but with a
`taller package. Similarly, in a smaller LED package of 1-2
`mm but with space restraints on the packaging, an LED with
`a lens presents design problems due to the lens height. If a
`reflector cup is used, be it a punched cup or a drilled cup,
`additional space is required.
`
`[0004] What is needed is a way to increase brightness of
`a LED package with a smaller size.
`
`SUMMARY OF THE INVENTION
`
`[0005] One aspect of the present invention provides a light
`emitting diode system including a housing including a light
`emission opening and a light emitting diode disposed within
`the housing. A first film layer covers the light emission
`opening and includes a uniaxial collimating film configured
`to direct light from the light emitting diode along a first axis.
`
`[0006] Another aspect of the present invention provides a
`method of collimating light. The method includes receiving
`light in a first collimating layer and directing a first portion
`of the received light through a second collimating layer
`along a first axis.
`
`[0007] Another aspect of the present invention provides a
`system for collimating light. The system includes means for
`receiving light in a first collimating layer.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`[0008] FIGS. IA, lB, and lC illustrate prior light emitting
`diode lighting systems;
`
`[0009] FIG. 2 illustrates one embodiment of a light emit(cid:173)
`ting diode lighting systems in accordance with the invention;
`
`[0010] FIGS. 3A, 3B, 3C, and 3D are top and side views
`of a first and second film layer in accordance with one
`embodiment of the invention;
`
`[0011] FIG. 4 illustrates another embodiment of a light
`emitting diode lighting system in accordance with the inven(cid:173)
`tion;
`
`[0012] FIG. 5 illustrates another embodiment of a light
`emitting diode lighting system in accordance with the inven(cid:173)
`tion;
`
`[0013] FIG. 6 illustrates another embodiment of a light
`emitting diode lighting system in accordance with the inven(cid:173)
`tion;
`
`[0014] FIG. 7 illustrates one embodiment of a method for
`collimating light in accordance with the invention;
`
`[0015] FIG. 8 illustrates another embodiment of a method
`for collimating light in accordance with the invention;
`
`[0016] FIG. 9 illustrates another embodiment of a method
`for collimating light in accordance with the invention; and
`
`[0017] FIG. 10 illustrates another embodiment of a
`method for collimating light in accordance with the inven(cid:173)
`tion.
`
`DETAILED DESCRIPTION
`
`[0018] FIG. 2 illustrates one embodiment of a light emit(cid:173)
`ting diode lighting system 200 in accordance with one aspect
`of the invention. Light emitting diode lighting system 200
`includes housing 205, light emitting diode 210 and base 215.
`Housing 205 includes a light emission opening 208 config(cid:173)
`ured to allow light emitted by light emitting diode 205 to
`radiate from within housing 205. Housing 205 surrounds
`light emitting diode 210, such that light emitting diode 210
`is disposed within housing 205.
`
`[0019]
`In one embodiment, base 215 includes a mirror(cid:173)
`finish layer attached to the housing 205, such that light
`emitting diode 210 rests upon the mirror-finish layer. A
`mirror-finish layer is any reflective surface, such as a mirror
`or other similarly reflective surface. In one embodiment, the
`mirror-finish layer includes a grooved surface configured to
`direct incoming light toward a first and second film layer
`230, 240 covering the light emission opening 208.
`
`[0020] Light emitting diode 210 emits light 220 at a
`plurality of angles. The light 220 is then refracted by the first
`and second film layers 230, 240. 8 illustrates the critical
`angle associated with Snell's law: if the angle of the light
`entering a medium, such as first film layer 230, is greater
`than 8, then the light has total internal reflection ("TIR");
`and if the angle is less than 8, the light is refracted.
`Additionally, Snell's law posits that if medium A is denser
`than medium B, light traveling from A into B is focused
`closer to the normal of the plane between medium A and
`medium B.
`
`[0021] A first and second film layer 230, 240 is disposed
`over at least a portion of the opening of the housing 205 and
`the light emission opening 208. In one embodiment, the first
`and second film layers cover the entire opening, while in
`other embodiments, the first and second film layers cover
`only a portion of the opening. In embodiments wherein the
`first and second film layers cover only a portion of the
`opening, the first and second film layers may cover the same
`portion, or at least partially different portions of the opening.
`The first and second film layers 230, 240 include a uniaxial
`collimating film configured to direct light emitted from the
`
`IPR PAGE 10
`
`

`
`US 2006/0285332 Al
`
`Dec. 21, 2006
`
`2
`
`light em1ttmg diode 210 along a first and second axis,
`respectively. Thus, light received by the first film layer 230
`is directed along a first axis, while light received by the
`second film layer 240 can be directed along a second axis.
`The second axis is offset from the first axis. In one embodi(cid:173)
`ment, the first axis is the x-axis, and the second axis is the
`y-axis. In one embodiment, the uniaxial collimating film is
`attached to the light emission opening 208. The uniaxial
`collimating film may be attached to the light emission
`opening 208 using any appropriate technique, such as a
`transparent adhesive or optical gel.
`
`[0022]
`In one embodiment, the uniaxial collimating film is
`implemented as Vikuiti Brightness Enhancement Film
`(BEF) III-10 T, available from 3M of St. Paul, Minn. In one
`embodiment, the uniaxial collimating film comprises a
`transmissive film with a grooved surface. For example, the
`grooved surface features prismatic properties in certain
`embodiments. It is preferred that the film is configured to
`concentrate approximately 40 to approximately 70 percent
`of the light generated by the light emitting diode to a center,
`although other configurations are anticipated. It is further
`preferred that the film is configured to resist deforming on
`exposure to environmental factors. Environmental factors
`include, without limitation, heat, cold, dust, and humidity.
`Maintaining the film in a clean and debris-free state helps to
`maximize light extraction, and brightness of the emitted
`light.
`
`[0023] Collimating the light in this fashion helps to reduce
`the FOY of the light emitting diode, and maximize the
`brightness within the effective FOY.
`
`[0024] FIGS. 3A and 3B illustrate one embodiment of a
`first film layer 230, in accordance with one aspect of the
`invention. FIG. 3A illustrates a top view of the first film
`layer at 310, while FIG. 3B illustrates a side view of the first
`film layer. Similarly, FIGS. 3C and 3D illustrate one
`embodiment of a second film layer 240, in accordance with
`one aspect of the invention. FIG. 3C illustrates a top view
`of the second film layer at 320, while FIG. 3D illustrates a
`side view of the second film layer. As noted above, the axes
`of film layers 230 and 340 can be offset by 90 degrees or any
`other angle.
`
`[0025] FIG. 4 illustrates another embodiment of a light
`emitting diode lighting system 400 in accordance with
`another aspect of the invention. For clarity of illustration,
`light emitting diode 210 is illustrated not emitting light. In
`addition to first and second film layers 230, 240, light
`emitting diode 210, housing 205 and surface 215, system
`400 includes an additional light guide 450 configured to
`diffuse light rays emitting from light emitting diode 210.
`Light guide 450 is illustrated as receiving light emitted by
`second film layer 240, but light guide 450 could also be
`placed between first and second film layers 230, 240, or
`between light emitting diode 210 and first film layer 230 in
`other embodiments. Those of ordinary skill in the art will
`readily recognize that placement of the diffuser will affect
`the effects of the diffuser. A light guide 450 may comprise
`any known tool to diffuse light, including liners.
`
`[0026] FIG. 5 illustrates a close up side view of a light
`emitting diode lighting system 500 in accordance with one
`aspect of the invention. light emitting diode lighting source
`210 emits light in the direction of first film layer 230. In one
`embodiment, light emitting diode 210 is sized to reduce lost
`
`light 555 that results from emitted light that does not enter
`first film layer 230 at a proper angle. For example, sizing the
`light emitting diode 210 to match the size of the first film
`layer may provide such a sizing.
`[0027] FIG. 5 further illustrates the normal angle 570 of
`light emitted by light emitting diode 210. Light 560 is
`refracted by first film layer 230 and is emitted from first film
`layer 230, concentrated on the center of the opening. Inci(cid:173)
`dent light 575 is allowable, and in embodiments featuring a
`reflective surface, incident light 575 will be reflected back
`toward the first film layer. However, incident light 580 is
`undesirable and the first film layer, in certain embodiments,
`is configured to minimize light reflected back toward the
`emitting light emitting diode.
`[0028] Light beam 583 is illustrated entering one portion
`of the first film layer, and being refracted to re-enter the first
`film layer at a different location. Such refraction will tend to
`increase light emitted in the desired direction, as a greater
`portion of the light being emitted will refract at desirable
`angles, minimizing light loss. For example, upon re-entering
`the first film layer, light beam 583 may be refracted in a
`desirable direction (depending on the angle), or light beam
`583 may be refracted toward a reflective surface that sup(cid:173)
`ports the light emitting diode, or another reflective surface.
`Other times, even after the refraction, light beam 583 may
`result in a lost light beam, but at least some light beams 583
`will be collimated toward the desired direction.
`[0029] FIG. 6 illustrates a side view of a light emitting
`diode system 600 in accordance with another aspect of the
`invention. System 600 includes light emitting diode 210,
`housing 205, and first film layer 230. System 600 further
`includes reflector 695.
`[0030] Reflector 695 is any surface configured to reflect a
`substantial portion of incident light. In one embodiment,
`reflector 695 is a mirror. In another embodiment, reflector
`695 is a mirror-finish layer. In yet another embodiment,
`reflector 695 comprises a grooved surface. In one embodi(cid:173)
`ment, reflector 695 is a sloped reflector. In one embodiment,
`reflector 695 is a flat surface disposed along a lower surface
`601 of the housing 205. In another embodiment, reflector
`695 features a smaller opening at the bottom and a larger
`opening at the top 602, with a sloped surface connecting the
`bottom and top, termed a "sloped reflector." In yet another
`embodiment, reflector 695 is a cup, either drilled or
`punched, into the housing.
`[0031] FIG. 7 illustrates one embodiment ofa method 700
`for collimating light in accordance with one aspect of the
`invention. Method 700 begins by receiving light in a first
`collimating layer at step 710. In one embodiment, the
`received light is emitted or generated by a light emitting
`diode package. In one embodiment, the first collimating
`layer is implemented as first film layer 230. The received
`light is refracted by the first collimating layer and separated
`into at least two portions including a first and second
`portion.
`[0032] A first portion of the received light is directed
`through a second collimating layer along a first axis at step
`720. In one embodiment, the second collimating layer is
`implemented as second film layer 240. The second colli(cid:173)
`mating layer receives the light refracted by the first colli(cid:173)
`mating layer and directs at least a portion of the light away
`from the source of the light.
`
`IPR PAGE 11
`
`

`
`US 2006/0285332 Al
`
`Dec. 21, 2006
`
`3
`
`[0033] A second portion of the received light is directed
`through the second collimating layer along a second axis
`offset from the first axis at step 730. In one embodiment, the
`first axis is the x-axis. In one embodiment, the second axis
`is the y-axis. In other embodiments, other axes are chosen
`for the first and second axis, such as an embodiment where
`it is desirable to collimate light off-angle from the light
`emitting diode emitting the light. Directing the received
`light through the first and second collimating layers colli(cid:173)
`mates the light, increasing the brightness of the light emitted
`from the light emitting diode as perceived by a viewer.
`
`[0034] FIG. 8 illustrates another embodiment of a method
`800 for collimating light in accordance with one aspect of
`the invention. Method 800 includes receiving light in a first
`collimating layer at step 810. In one embodiment, step 810
`is implemented as step 710. A first portion of the received
`light is directed through a second collimating layer along a
`first axis at step 820. In one embodiment, step 820 is
`implemented as in step 720. A second portion of light is
`directed through the second collimating layer along a second
`axis offset from the first axis at step 830. In one embodiment,
`step 830 is implemented as in step 730.
`
`[0035] A third portion of the received light is directed
`toward a reflective surface at step 840. In one embodiment,
`the third portion of the received light is reflected back
`toward the housing. For example, the third portion of the
`received light is reflected toward the mirror-surface layer in
`one embodiment. In another embodiment, the third portion
`of the received light is reflected toward a grooved surface.
`
`In one embodiment, receiving light in the first
`[0036]
`collimating layer includes generating light. In another
`embodiment, directing the first portion of the received light
`includes transmitting the received light when the received
`light has a predetermined angle. In another embodiment,
`directing the second portion of the received light includes
`reflecting the received light when the received light does not
`have the predetermined angle.
`
`[0037] FIG. 9 illustrates another embodiment of a method
`900 for collimating light in accordance with one aspect of
`the invention. Method 900 includes receiving light in a first
`collimating layer at step 910. In one embodiment, step 910
`is implemented as step 710. A first portion of the received
`light is directed through a second collimating layer along a
`first axis at step 920. In one embodiment, step 920 is
`implemented as in step 720. A second portion of light is
`directed through the second collimating layer along a second
`axis offset from the first axis at step 930. In one embodiment,
`step 930 is implemented as in step 730.
`
`[0038] Light is reflected from a mirror-surface layer
`toward the first and second collimating layers at step 940. In
`one embodiment, the mirror-surface layer is a flat surface
`supporting the light emitting diode. In another embodiment,
`the mirror-surface layer is sloped. In yet another embodi(cid:173)
`ment, the mirror-surface layer is a cup supporting the light
`emitting diode.
`
`[0039] FIG. 10 illustrates another embodiment of a
`method 1000 for collimating light in accordance with one
`aspect of the invention. Method 1000 includes receiving
`light in a first collimating layer at step 1010. In one
`embodiment, step 1010 is implemented as step 710. A first
`portion of the received light is directed through a second
`
`collimating layer along a first axis at step 1020. In one
`embodiment, step 1020 is implemented as in step 720. A
`second portion of light is directed through the second
`collimating layer along a second axis offset from the first
`axis at step 1030. In one embodiment, step 1030 is imple(cid:173)
`mented as in step 730.
`
`[0040] The directed light is diffused with at least one of a
`liner and a light guide at step 1040. The liner and/or light
`guide may be placed between the light emitting diode and
`the first collimating layer, between the first and second
`collimating layers, or outside the light emitting diode pack(cid:173)
`age.
`
`[0041] Directing light through the first and second colli(cid:173)
`mating layers, as described with respect to methods 700,
`800, 900 and 1000, results in collimating the light received
`by the first and second collimating layers. Such collimation
`optimally results in a reduced FOY for a light source
`directing light beams toward the first and second collimating
`layers, and an increased effective brightness based on the
`reduced FOY.
`
`[0042] While the embodiments of the invention disclosed
`herein are presently considered to be preferred, various
`changes and modifications can be made without departing
`from the scope of the invention. The scope of the invention
`is indicated in the appended claims and all changes that
`come within the meaning and range of equivalents are
`intended to be embraced therein.
`
`We claim:
`1. A light emitting diode system comprising:
`
`a housing including a light emission opening;
`
`an light emitting diode disposed within the housing;
`
`a first film layer disposed across at least a portion of the
`light emission opening, the first film layer including
`uniaxial collimating film configured to direct light from
`the light emitting diode
`2. The system of claim 1, wherein the first film layer is
`configured to direct light from the light emitting diode along
`a first axis and further comprising:
`
`a second film layer disposed on the first film layer, the
`second film layer including uniaxial collimating film
`configured to direct light from the light emitting diode
`along a second axis offset from the first axis.
`3. The system of claim 1 wherein the housing includes a
`sloped reflector.
`4. The system of claim 3 wherein the sloped reflector
`includes a bottom and a top, and wherein the radius of the
`bottom of the sloped reflector is smaller than the radius of
`the top of the sloped reflector.
`5. The system of claim 3 wherein the sloped reflector
`comprises a mirror.
`6. The system of claim 1 wherein the light emitting diode
`is disposed upon a mirror-finish layer attached to the hous(cid:173)
`ing.
`7. The system of claim 6 wherein the mirror-finish layer
`includes a grooved surface configured to direct incoming
`light toward the first and second film layers.
`8. The system of claim 1 wherein the uniaxial collimating
`film comprises a grooved surface.
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`IPR PAGE 12
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`US 2006/0285332 Al
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`Dec. 21, 2006
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`4
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`9. The system of claim 1 wherein the uniaxial collimating
`film is configured to concentrate approximately 40 to
`approximately 70 percent of light generated by the light
`emitting diode to a center.
`10. The system of claim 1 wherein the uniaxial collimat(cid:173)
`ing film resists deforming on exposure to environmental
`factors.
`11. The system of claim 1 further comprising at least one
`of a liner and a light guide to diffuse light rays.
`12. A method of collimating light, the method comprising:
`
`receiving light in a first collimating layer;
`
`directing a first portion of the received light through a
`second collimating layer along a first axis; and
`
`directing a second portion of light through the second
`collimating layer along a second axis offset from the
`first axis.
`13. The method of claim 12 wherein the light is generated
`by a light emitting diode package, and wherein the first
`portion of the received light is directed through the second
`collimating layer along a first axis, and wherein the second
`portion of light is directed through the second collimating
`layer along a second axis offset from the first axis.
`14. The method of claim 12 further comprising directing
`a third portion of received light toward a reflective surface
`of the housing.
`15. The method of claim 12 further comprising reflecting
`light from a mirror-surface layer toward the first and second
`collimating layers.
`16. The method of claim 12 further comprising diffusing
`the directed light with at least one of a liner and a light guide.
`
`17. The method of claim 12 wherein receiving light in a
`first collimating layer comprises generating light, and
`wherein directing a first portion of the received light com(cid:173)
`prises transmitting the received light when the received light
`has a predetermined angle, and wherein directing the second
`portion of the received light comprises reflecting the
`received light when the received light does not have the
`predetermined angle.
`18. A system for collimating light, the system comprising:
`
`means for receiving light in a first collimating layer;
`
`means for directing a first portion of the received light
`through a second collimating layer along a first axis;
`and
`
`means for directing a second portion of light through the
`second collimating layer along a second axis offset
`from the first axis.
`19. The system of claim 18 further comprising means for
`diffusing light.
`20. The system of claim 18 wherein means for directing
`a first portion of the received light through a second colli(cid:173)
`mating layer comprises means for directing a first portion of
`the received light through a second collimating layer along
`a first axis and wherein means for directing a second portion
`of light through the second collimating layer comprises
`means for directing a second portion of light through the
`second collimating layer along a second axis offset from the
`first axis.
`
`* * * * *
`
`IPR PAGE 13