United States Patent [t9J
`Winston et al.
`
`lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
`5,303,322
`Apr. 12, 1994
`
`US005303322A
`[11] Patent Number:
`[45] Date of Patent:
`
`[75]
`
`[54] TAPERED MULTILAYER LUMINAIRE
`DEVICES
`Inventors: Roland Winston; Benjamin A.
`Jacobson, both of Chicago; Robert L.
`Holman, Naperville; Neil A. Gitldnd,
`Chicago, all of Ill.
`[73] Assignee: NiOptics Corporation, Evanston, Ill.
`[21] Appl. No.: 29,883
`Mar. 11, 1993
`[22] Filed:
`
`[56]
`
`Related U.S. Application Data
`. [63] Continuation-in-part of Ser. No, 855,838, Mar. 23,
`1992, Pat. No. 5,237,641.
`Int. CI.s ................................................ G02B 6/26
`[51]
`[52] U.S. CI ....................................... 385/146; 385/43;
`385/901; 385/129; 385/131
`[58] Field of Search ................. 385/43, 129, 130, 131,
`385/140, 146, 147, 901, 31; 359/599, 833, 834
`References Cited
`U.S. PATENT DOCUMENTS
`2,347,665 5/1944 Christensen eta!. ................. 362/31
`2,712,593 7/1955 Merchant .............................. 362/27
`3,617,109 11/1971 Tlen ...................................... 385/43
`3,752,974 8/1973 Baker eta!. ............................. 240/1
`3,832,028 8/1974 Kapron ................................. 385/43
`3,980,392 9/1976 Aunacher .............................. 385/43
`4,059,916 11/1977 Tachihara et al ..................... 40/130
`4,111,538 · 9/1978 Sheridon ............................. 353/122
`4,114,592 9/1978 Winston .............................. 126/270
`4,161,015 7/1979 Dey eta!. ........................... 362/263
`4,176,908 12/1979 Wagner ............................ 350/96.15
`4,212,048 7/1980 Castleberry ........................... 362/19
`4,240,692 12/1980 Winston ........................... 350/96.10
`4,257,084 3/1981 Reynolds .............................. 362/31
`4,277,817 7/1981 Hehr ..................................... 362/31
`4,323,951 4/1982 Pasco .................................... 362/27
`4,373,282 2/1983 Wragg ................................... 40/546
`4,420,796 12/1983 Mori ...................................... 362/32
`4,453,200 6/1984 Troka eta!. .......................... 362/31
`4,528,617 7/1985 Blackington .......................... 362/32
`4,547,043 10/1985 Penz ...................................... 362/32
`4,573,766 3/1986 Bournsy, Jr. eta!. .............. 350/345
`4,618,216 10/1986 Suzawa ................................. 359/49
`4,648,690 3/1987 Obe ..................................... 350/321
`
`4,649,462 3/1987 Dobrowolski eta!. ................ 362/2
`4,706,173 11/1987 Hamada et al ...................... 362/341
`4,729,068 3/1988 Ohe ....................................... 362/31
`4,735,495 4/1988 Henkes ................................ 362/310
`4,737,896 4/1988 Mochizulki et al ................. 362/301
`4,747,223 5/1988 Bonds .................................... 40/219
`4,765,718 8/1988 Henkes .................................. 359/49
`4,799,050 1/1989 Prine eta!. .......................... 340/765
`4,799,137 1/1989 Abo ............ ; ........................ 362/309
`4,832,458 5/1989 Fergason ............................. 350/338
`
`(List continued on next page.)
`
`OTHER PUBLICATIONS
`"Flat Panel Backlight Reflecting Device," R. L. Gar(cid:173)
`win and R. T. Hodgson, IBM Technical Disclosure Bul(cid:173)
`letin, vol. 31, No.2, Jul. 1988, pp. 190-191.
`"Dielectric Totally Internally Reflecting Concentra(cid:173)
`tors" Xisohui, Ming, Roland Winston and Joseph 0'(cid:173)
`Gallagher, Applied Optics.. vol. 26, Jan. 15, 1987, pp.
`300-305.
`
`Primary Examiner-John D. Lee
`Assistant Examiner-Phan Thi Heartney
`Attorney, Agent, or Firm-Reinhart, Boerner, Van
`Deuren, Norris & Rieselbach
`ABSTRACf
`[57]
`An optical device for collecting light and selectively
`outputting or concentrating the light. A wedge layer
`has an optical index of refraction n1. and top, bottom
`and side surfaces intersecting to define an angle of incli(cid:173)
`nation d. A back surface spans the top, bottom and side
`surface. A first layer is coupled to the bottom surface of
`the layer and has an index of refraction n2. The first
`layer index n2 causes light input through the back sur(cid:173)
`:face of the layer to be preferentially output into the first
`layer. A second layer is coupled to the bottom of the
`first layer and selectively causes output of light into
`ambient. Additional layers, such as an air gap, can be
`provided adjacent to the wedge shaped layer. The
`wedge shaped layer can also have a variable index of
`refraction n (x,y,z).
`
`69 Claims, 23 Drawing Sheets
`
`BJ
`10~ ~-----1--------------------~
`~--------------------------~
`
`78
`
`66
`
`LG Display Ex. 1013
`
`LGD_001316
`
`

`

`5,303,322
`Page 2
`
`U.S. PATENT DOCUMENTS
`4,838,661 6/1989 McKee eta!. ...................... 350/345
`4,842,378 6/1989 Flasck et al ......................... 350/345
`4,907,044 3/1990 Schellhorn eta!. .................. 357/17
`4,907,132 3/1990 Parker ................................... 362!32
`4,914,553 4/1990 Hamada et al. ..................... 362/321
`4,915,479 4/1990 Clarke ................................. 358/345
`4,936,659 6/1990 Anderson et al. .................... 359/49
`4,950,059 8/1990 Roberts ................................. 362/32
`4,958,915 9/1990 Okada et al ......................... 350/345
`4,965,876 10/1990 Foldi et al ........................... 362!247
`4,974,122 11/1990 Shaw ..................................... 362/31
`4,974,353 12/1990 Norfolk ................................. 40/447
`4,985,809 1!1991 Matsui et al .......................... 362/31
`4,989,933 2/1991 Duguay ............................ 350/96.10
`4,992,916 2/1991 Henkes ................................ 362/255
`4,998,188 3/1991 Degelmann ......................... 362/147
`5,019,808 5/1991 Prince et al ......................... 340/765
`5,039,207 8/1991 Green .................................... 359/49
`5,040,098 8/1991 Tanaka et al ......................... 362/31
`5,040,878 8/1991 Eichenlaub ......................... 350/345
`5,044,734 9/1991 Sperl eta!. ............................ 359/49
`5,046,805 9/1991 Simon ................................... 385/31
`
`5,046,829 9/1991 Worp .................................... 359/49
`5,050,946 9/1991 Hathaway et al .................... 385/33
`5,051,551 9/1991 Doyle .................................. 250/341
`5,053,765 10/1991 Sonehara eta!. .............. 340/815.31
`5,083,120 1/1992 Nelson ................................ 340/784
`5,101,325 3/1992 Davenport et al ................... 362/31
`5,128,783 7/1992 Abileah et al ........................ 359/49
`5,128,787 7/1992 Blonder ................................. 359/70
`5,128,846 7/1992 Mills et al ........................... 362/224
`OTHER PUBLICATIONS
`"Optics of Two-Stage Photovaltaic Concentrators
`with Dielectric Second Stages", Xisohul, Ning, Roland
`Winston and Joseph O'Gallagher, Applied Optics, vol.
`26, Apr. 1, 1987, pp. 1207-1212.
`"New Backlighting Technologies for LCDs", Hatha(cid:173)
`way et al., Society for Information Display Digest, vol. 22,
`May 1991, pp. 751-754. "Parts that Glow", A. Bhumen(cid:173)
`feld and S. Jones, Machine Design, Jul. 1985, pp. 1-11.
`"Directional Diffuser Lens Array for Backlit LCDs",
`R. I. McCartney and D. Syroid, Japan Display, pp.
`259-262 (1992).
`
`LGD_001317
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 1 of 23
`
`5,303,322
`
`g~1 11
`-PRIOR ART- ~
`
`ec
`
`OBSERVER
`~--------- ----------------~
`~--------- ----~----------~
`40
`
`29
`
`LGD_001318
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 2 of 23
`
`5,303,322
`
`12
`
`38
`
`LGD_001319
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 3 of 23
`
`5,303,322
`
`F
`
`F
`
`12
`
`LGD_001320
`
`

`

`U.S. Patent
`
`. Apr. 12, 1994
`
`Sheet 4 of 23
`
`5,303,322
`
`47:-l 1:-==--------=--
`
`LGD_001321
`
`

`

`US. Patent
`
`U.S. P a t e n t
`
`Apr. 12, 1994
`Apr. 12, 1994
`
`S h e e t 5 o f 2 3
`Sheet 5 of 23
`
`5 , 3 0 3 , 3 2 2
`5,303,322
`
`
`
`LGD_001322
`
`LGD_001322
`
`

`

`U.s. P a t e n t
`
`A p r . 12, 1 9 9 4
`
`S h e e t 6 o f 2 3
`
`5 , 3 0 3 , 3 2 2
`
`BRIGHTNESS
`8
`
`6
`
`- 5 TO 30
`
`-10
`
`TO 40
`
`TO 50
`-15
`- " ,
`" ' \
`0 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
`
`-
`
`\
`
`\
`WEDGE/
`
`60
`
`90
`
`4
`
`2
`
`- 9 0
`
`- 6 0
`
`0
`- 3 0
`VIEWING ANGLE
`
`30
`(DEGREES)
`
`LGD_001323
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 7 of 23
`
`5,303,322
`
`BRIGHTNESS
`
`8
`
`6
`
`4
`
`2
`
`-18 TO 18
`
`-18 TO 30
`
`-90
`
`...,so
`
`30
`0
`-30
`VIEWING ANGLE (DEGREES)
`
`60
`
`90
`
`BRIGHTNESS
`8
`
`4
`
`2
`
`I
`
`I
`
`-90
`
`;')(
`~·
`
`~-*-*_H"_
`~,..
`>t"'
`
`>E- -*"' -K- " '
`' )(
`\
`WEDGE..>,
`X
`
`-60
`
`.
`30
`0
`-30
`VIEWING ANGLE (DEGREES)
`
`60
`
`90
`
`LGD_001324
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 8 of 23
`
`5,303,322
`
`BRIGHTNESS (fl.)
`5.4
`
`4
`
`3.5
`
`3
`
`2.5
`
`2
`
`1.5
`
`0.5
`
`0
`
`4
`
`700
`BRIGHTNESS
`600
`
`500
`
`400
`
`300
`
`200
`
`100
`
`0
`
`LGD_001325
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 9 of 23
`
`5,303,322
`
`3RIGHTNESS
`260
`240
`220
`200
`180
`160
`140
`120
`100
`80
`60
`40
`20~~~~~~~~~~~~~~~~
`
`BRIGHTNESS
`320
`300
`280
`260
`240
`220
`200
`180
`160
`140
`120
`100
`80
`60
`40
`20
`o~~~~~~~~~~~~
`24 42 ANGLE
`-46 -38 -34 -30 -24 -18 2
`
`10
`
`LGD_001326
`
`

`

`U.S. Patent
`
`. Apr. 12, 1994
`
`Sheet 10 of 23
`
`5,303,322
`
`BRIGHTNESS
`500
`
`450
`
`400
`
`350
`
`300
`
`250
`
`200
`
`150
`100
`
`LUMINANCE (fl.)
`500
`
`400
`
`300
`
`200
`
`100
`
`0+-~~~~~~~~~~~~~~~
`90
`60
`30
`0
`-30
`-60
`-90
`VERTICAL ANGLE(DEGREES)
`
`LGD_001327
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 11 of 23
`
`5,303,322
`
`/'46
`
`10~
`
`83
`
`fA· 6.;1
`~
`~-----J--------------------~
`~--------------------------~
`62
`
`78
`
`10~
`
`70
`
`LGD_001328
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 12 of 23
`
`5,303,322
`
`92
`
`93
`
`12
`
`76
`
`-PRIOR ART-
`~~.7
`
`LGD_001329
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 13 of 23
`
`5,303,322
`
`EFFECTIVE
`VIEWING
`AREA
`
`V
`
`.... ....
`
`.... .... ....
`
`....
`
`TOP OF
`SCREEN CUTS OFF
`ye.... .... .... PROGRESSIVELY
`..
`................ '-f
`(d-.e-.f)
`~--- 0=500 t.4t.4 ----~ .. 1 ..............
`
`.... .... .... ....
`
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`, SCREEN
`DIMMING
`
`t
`
`v
`
`150MM
`
`T
`L
`
`~---· 0=500 t.tt.4 - - - - - . .
`
`LGD_001330
`
`

`

`U . s .
`
` P a t e n t
`
` 1 2 , 1 9 9 4
`
`A p r .
`
`S h e e t 1 4 o f 2 3
`
`5 , 3 0 3 , 3 2 2
`
`
`
`LGD_001331
`
`

`

`Apr. 12, 1994
`
`U.S. Patent
`t----=======--
`
`10~
`
`Sheet 15 of 23
`
`5,303,322
`
`=======---'J
`
`'=-126
`
`124
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`129
`
`12
`
`12
`
`LGD_001332
`
`

`

`US. Patent
`
`U.S. P a t e n t
`
`. A p r . 12, 1994
`.Apr. 12, 1994
`
`S h e e t 16 o f 23
`Sheet 16 of 23
`
`5 , 3 0 3 , 3 2 2
`5,303,322
`
`~138
`
`F
`rocus
`
`FOCUS
`
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`
`/ " 1 0
`146
`
`148
`
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`150
`
`LGD_001333
`
`LGD_001333
`
`

`

`U . S . P a t e n t
`
`A p r , 12, 1994
`
`S h e e t 1 7 o f 23
`
`5 , 3 0 3 , 3 2 2
`
`EFFECTIVE
`VIEWING
`AREA
`
`~10
`
`152
`
`171
`
`166
`
`170
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`
`r===
`
`LGD_001334
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 18 of 23
`
`5,303,322
`
`10~
`
`12
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`
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`
`LGD_001335
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 19 of 23
`
`5,303,322
`
`10~
`
`12
`
`202
`
`198
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`LGD_001336
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 20 of 23
`
`5,303,322
`
`217 220
`
`217
`
`239
`
`12
`
`LGD_001337
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 21 of 23
`
`5,303,322
`
`LGD_001338
`
`

`

`U.S. Patent
`
`. Apr. 12, 1994
`
`Sheet 22 of 23
`
`5,303,322
`
`~· 14
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`
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`104
`
`102
`
`LGD_001339
`
`

`

`U.S. Patent
`
`Apr. 12, 1994
`
`Sheet 23 of 23
`
`5,303,322
`
`22 ~ Dt
`
`1/11 = 35°-(0.133 DEG/t.UN)•X
`'1/12 = 35°+(0.133 DEG/MIN)•X
`
`101
`
`X=75
`
`I X=O
`
`101 X=75
`
`LGD_001340
`
`

`

`1
`
`5,303,322
`
`TAPERED MULTILAYER LUMINAIRE DEVICES
`
`30
`
`This is a continuation-in-part of copending applica(cid:173)
`tion Ser. No. 07/855,838 filed on Mar. 23, 1992, U.S. 5
`Pat. No. 5,237,641.
`The present invention is concerned generally with a
`luminaire device for providing selected illumination.
`More particularly, the invention is concerned with ta(cid:173)
`pered luminaires, such as a wedge or disc shape, for 10
`backlighting and control of angular range of illumina(cid:173)
`tion and light concentration generally.
`A variety of applications exist for luminaire devices,
`such as, for liquid crystal displays. For flat panel liquid
`crystal displays, it is important to provide adequate 15
`backlighting while maintaining a compact lighting
`source. It is known to use wedge shaped optical devices
`for general illumination purposes. Light is input to such
`devices at the larger end; and light is then internally
`reflected off the wedge surfaces until the critical angle 20
`of the reflecting interface is reached, after which light is
`output from the wedge device. Such devices, however,
`have only been used to generally deliver an uncol(cid:173)
`limated lighting output and often have undesirable spa(cid:173)
`tial and angular output distributions. For example, some 25
`of these devices use white painted layers as diffuse re(cid:173)
`flectors to generate uncollimated output light.
`It is therefore an object of the invention to provide an
`improved optical device and method of manufacture.
`It is another object of the invention to provide a
`novel three dimensional luminaire.
`It is a further object of the invention to provide an
`improved multilayer tapered luminaire for optical pur(cid:173)
`poses, such as for controlled angular output backlight- 35
`in g.
`It is still another object of the invention to provide a
`novel tapered luminaire device for controlled transmis(cid:173)
`sion or concentration of light.
`It is an additional object of the invention to provide a 40
`novel optical device for providing collimated illumina(cid:173)
`tion from the device.
`It is yet a further object of the invention to provide an
`improved tapered luminaire having an intervening air
`gap layer.
`It is still another object of the invention to provide a
`novelluminaire allowing controlled and focused output
`illumination, or controlled angular input for concentra(cid:173)
`tion.
`It is yet a further object of the invention to provide an 50
`improved illumination system wherein a light source,
`such as a compound parabolic concentrator, a flumes(cid:173)
`cent tubular light source, or variable parametric func(cid:173)
`tional source is coupled to a multilayer optical device
`for generating an output.
`It is still a further object of the invention to provide a
`novelluminaire optical device having a variable index
`of refraction over the spatial parameters of a luminaire.
`It is yet an additional object of the invention to pro(cid:173)
`vide an improved luminaire wedge device having non- 60
`linear thickness variation and variable wedge angle <I>
`along selected spatial parameters enabling compensa(cid:173)
`tion for light output irregularities.
`Other objects, features and advantages of the present
`invention will be readily apparent from the following 65
`description of the preferred embodiments thereof, taken
`in conjunction with the accompanying drawings de(cid:173)
`scribed below.
`
`45
`
`55
`
`2
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 shows a prior art wedge shaped device;
`FIG. 2A illustrates a multilayer tapered luminaire
`device constructed in accordance with the invention;
`FIG. 2B is a magnified partial view of the junction of
`the wedge layer, the first layer and the second faceted
`layer; FIG. 2C is an exaggerated form of FIG. 2A
`showing a greatly enlarged second faceted layer; FIG.
`2D is a partial view of the junction of the three layers
`illustrating the geometry for brightness determinations;
`FIG. 2E is a multilayer wedge device with a light redi(cid:173)
`recting, internally transmitting layer on the bottom;
`FIG. 2F shows a wedge device with a lower surface
`translucent layer; FIG. 2G shows a wedge layer with a
`lower surface refracting faceted layer; FIG. 2H shows a
`wedge layer with a lower surface refracting layer and
`curved facets thereon;
`FIG. 21 shows a wedge layer with a refracting layer
`of facets having variable facet angles; FIG. 2J shows a
`single refracting prism coupled to a wedge layer; FIG.
`2K shows a single refracting prism coupled to a wedge
`layer and with an integral lens; FIG. 2L shows a reflect(cid:173)
`ing faceted layer coupled to a wedge device; FIG. 2M
`shows a reflecting faceted layer with curved facet an(cid:173)
`gles and coupled to a wedge device; FIG. 2N shows a
`flat reflecting facet on a wedge layer and FIG. 20
`shows a curved reflecting facet on a wedge layer;
`FIG. 3 shows the angular output light due to the facet
`geometry.
`FIG. 3A illustrates a multilayer wedge device with
`curved facets on the ambient side of the second layer
`and FIG. 3B shows a magnified partial view of the
`junction of the various layers of the device;
`FIG. 4A shows calculated brightness performance
`over angle for an asymmetric range of angles of illumi(cid:173)
`nation; FIG. 4B shows calculated brightness distribu(cid:173)
`tion performance over angle for a more symmetric
`angle range; FIG. 4C illustrates calculated brightness
`performance over angle for the symmetry of FIG. 4B
`and adding an external diffuser element; FIG. 4D illus(cid:173)
`trates an output using flat reflecting facets, no parallel
`at half-maximum brightness
`full-width
`diffuser;
`(FWHM)=7 degrees; FIG. 4E illustrates an example of
`nearly symmetrical output distribution; measured using
`flat facets with parallel lenticular diffuser; FWHM = 34
`degrees; FIG. 4F illustrates an example of asymmetrical
`output distribution, measured using curved facets;
`FWHM=32 degrees; FIG. 4G illustrates an example
`asymmetrical output distribution, measured using
`curved facets; FWHM=26 degrees; FIG. 4H illustrates
`an example of a bimodal output distribution, measured
`using one faceted reflecting layer and one faceted re(cid:173)
`fractive layer; and FIG. 41 illustrates an example of an
`output distribution with large "tails", measured using a
`diffuse reflective bottom redirecting layer and a refrac(cid:173)
`ting/internally-reflecting top redirecting layer;
`FIG. SA shows a top view of a disc shaped light
`guide and FIG. SB illustrates a cross section taken along
`SB-SB in FIG. SA;
`FIG. 6A shows a cross sectional view of a multilayer
`tapered luminaire device with an air gap layer included;
`FIG. 6B shows another tapered luminaire in cross sec(cid:173)
`tion with a compound parabolic light source/concen(cid:173)
`trator; FIG. 6C illustrates another tapered luminaire in
`cross section with a variable parametric profile light
`source and a lenticular diffuser; and FIG. 60 shows
`
`LGD_001341
`
`

`

`5,303,322
`
`20
`
`3
`another tapered luminaire in cross section with non(cid:173)
`monotonic wedge layer thickness;
`FIG. 7 illustrates a reflective element disposed con(cid:173)
`centrically about a light source;
`FIG. 8 illustrates a reflective element disposed about
`a light source with maximum displacement between the
`reflector center of curvature and the center of the light
`source;
`FIG. 9A illustrates use of a redirecting layer to pro(cid:173)
`vide a substantially similar angular distribution emanat- 10
`ing from all portions of the device and FI.G. 9B illus(cid:173)
`trates use of a redirecting layer to a vary angular distri(cid:173)
`bution emanating from different portions of the device,
`and specifically to focus the various angular distribu(cid:173)
`tions to enhance their overlap at a selected target dis- 15
`tance;
`FIG. 10 illustrates one form of pair of lenticular ar(cid:173)
`rays of a luminaire; and
`FIG. 11 illustrates a lenticular diffuser array and
`curved facet layer of a luminaire;
`FIG. 12A illustrates a wedge shaped luminaire hav(cid:173)
`ing a pair of diffraction gratings or hologram layers;
`FIG. 12B shows a wedge shaped luminaire with a pair
`of refracting facet layers and diffusers; FIG. 12C illus- 25
`trates a wedge shaped luminaire with a pair of faceted
`layers; FIG. 12D shows a wedge shaped luminaire with
`two refracting single facet layers; FIG. 12E illustrates a
`wedge shaped luminaire with a refracting single facet
`layer and a bottom surface redirecting layer; FIG. 12F 30
`shows a luminaire with a top surface redirecting layer
`of a refracting faceted layer and a bottom surface re(cid:173)
`fracting and internally reflecting layer; FIG. 12G illus(cid:173)
`trates a luminaire with a top surface refracting/inter(cid:173)
`nally reflecting faceted layer and a bottom surface re- 35
`fracting/internally reflecting faceted layer; FIG. 12H
`shows a luminaire with a top surface refracting faceted
`layer and a bottom surface refracting/internally reflect(cid:173)
`ing faceted layer; FIG. 121 illustrates a luminaire with a
`bottom surface specular reflector and a top layer trans- 40
`mission diffraction grating or transmission hologram;
`FIG. 12J shows a luminaire with a bottom surface spec(cid:173)
`ular reflector and a top surface refracting faceted layer
`and diffuser; FIG. 12K illustrates a luminaire with a
`bottom layer specular reflector and a top layer refrac- 45
`ting/internally reflecting faceted layer; FIG. 12L shows
`a luminaire with a bottom specular reflector and a top
`layer;
`layer refracting/internally reflecting. faceted
`FIG. 12M illustrates a luminaire with an initial reflector
`section including an integral lenticular diffuser; FIG. 50
`12N shows a luminaire with a roughened initial reflec(cid:173)
`tor section of a layer; FIG. 120 illustrates a luminaire
`with an eccentric light coupler and converging to the
`wedge shaped section; FIG. 12P shows a luminaire with
`an eccentric light coupler and a diffuser and roughened 55
`or lenticular reflector; FIG. 12Q illustrates a luminaire
`with a bottom specular or diffusely reflecting layer and
`a top refracting layer and FIG. 12R shows a luminaire
`for generating a "bat wing" light output;
`FIG. 13 illustrates a combination of two wedge 60
`shaped sections formed integrally and using two light
`sources;
`FIG. 14 shows a tapered disk luminaire including a
`faceted redirecting layer;
`FIG. 15 illustrates a luminaire operating to provide a 65
`collimated light output distribution;
`FIG. 16A shows a prior art ambient mode LCD and
`FIG. 16B illustrates a prior art transflective LCD unit;
`
`4
`FIG. 17 shows a luminaire operative in ambient and
`active modes with a faceted redirecting layer and a
`lenticular diffuser; and
`FIGS. 18A & 18B illustrate a luminaire with an array
`5 of micro-prisms for a faceted surface disposed over a
`diffuse backlight.
`DETAILED DESCRIPTION OF PREFERRED
`EMBODIMENTS
`A multilayer luminaire device constructed in accor(cid:173)
`dance with one form of the invention is illustrated in
`FIG. 2 and indicated generally at 10. A prior art wedge
`11 is shown generally in FIG. 1. In this wedge 11 the
`light rays within the wedge 11 reflect from the surfaces
`until the angle of incidence is less than the critical angle
`(sin -11/n) where n is the index of refraction of the
`wedge 11~ The light can exit equally from both top and
`bottom surfaces of the wedge 11, as well as exiting at
`grazing angles.
`The multilayer luminaire device 10 (hereinafter "de(cid:173)
`vice 10") shown in FIG. 2A includes a wedge layer 12
`which has a characteristic optical index of refraction of
`nt. The term "wedge layer" shall be used herein to
`include all geometries having converging top and bot(cid:173)
`tom surfaces with wedge shaped cross sectional areas.
`The x, y and z axes are indicated within FIGS. 2A and
`2C with the "y" axis perpendicular to the paper. Typi(cid:173)
`cal useful materials for the wedge layer 12 include al(cid:173)
`most any transparent material, such as glass, polymethyl
`methacrylate, polystyrene, polycarbonate, polyvinyl
`chloride, methyl methacrylate/styrene copolymer
`(NAS) and sytrene/acrylonitrile. The wedge layer 12 in
`FIG. 2A further includes a top surface 14, a bottom
`surface 16, side surfaces 18, edge 26 and a back surface
`20 of thickness t 0 spanning the top, bottom and side
`surfaces. A light source, such as a tubular fluorescent
`light 22, injects light 24 through the back surface 20 into
`the wedge layer 12. The light 24 is internally reflected
`from the various wedge layer surfaces and is directed
`along the wedge layer 12 toward the edge 26. Other
`possible light sources can be used. and will be described
`hereinafter. Generally, conventional light sources pro(cid:173)
`vide substantially incoherent, uncollimated light; but
`coherent, collimated light can also be processed by the
`inventions herein.
`For the case where the surfaces 14 and 16 are flat, a
`single angle of inclination 4> for a linear wedge is de(cid:173)
`fined by the top surface 14 and the bottom surface 16. In
`the case of nonlinear wedges·, a continuum of angles 4>
`are definable; and the nonlinear wedge can be designed
`to provide the desired control oflight output or concen(cid:173)
`tration. Such a nonlinear wedge will be described in
`more detail later.
`In the embodiment of FIG. 2A a first layer 28 is
`coupled to the wedge layer 12 without any intervening
`air gap, and the first layer 28 has an optical index of
`refraction n2 and is optically coupled to the bottom
`surface 16. The first layer 28 can range in thickness
`from a few light wavelengths to much greater thick(cid:173)
`nesses and accomplish the desired functionality. The
`resulting dielectric interface between the wedge layer
`12 and the first layer 28 has a higher critical angle than
`at the interface between the wedge layer 12 and ambi(cid:173)
`ent. As will be apparent hereinafter, this feature can
`enable preferential angular output and collimation of
`the light 24 from the device 10.
`Coupled to the first layer 28 is a second layer 30 (best
`seen in FIG. 2B) having an optical index of refraction
`
`LGD_001342
`
`

`

`5,303,322
`
`2_n22)/{n32_n22)]1
`1
`
`6
`5
`reflected back through the wedge layer 12. For exam-
`n3 which is greater than n2, and in some embodiments
`pie, in FIG. 2F the device 10 can include a translucent
`preferably greater than n,. This configuration then al-
`layer 37. In another form of this embodiment shown in
`lows the light 24 to leave the first layer 28 and enter the
`FIG. 2G, a refracting layer 38 is shown. The refracting
`second layer 30. In the embodiment of FIG. 2A there
`are substantially no intervening air gaps between the 5 layer 38 can include flat facets 39 for providing a colli-
`mated output. Also shown in phantom in FIG. 2G is a
`first layer 28 and the second layer 30. In the preferred
`transverse lenticular diffuser 83 which will be described
`form of the invention illustrated in FIG. 2A, n1 is about
`in more detail hereinafter. The diffuser layer 83 can be
`1.5, n2<l.S and n3;§n1. Most preferably, n,=l.5,
`used with any of the invention geometries, including
`n2<l.S (such as about one) and n3;§n1.
`In such a multilayer configuration for the device 10 10 above the wedge layer 12 as in FIG. 6A.
`In yet another example shown in FIG. 2H, the re-
`shown in FIG. 2, the wedge layer 12 causes the angle of
`fracting layer 38 can include curved facts 41 for provid-
`incidence for each cyclic time of reflection from the top
`ing a smoothly broadened output over a desired angular
`surface 14 to decrease by the angle of inclination 2cj>
`distribution. In a further example shown in FIG. 21, the
`(relative to the normal to the plane of the bottom sur-
`face 16). When the angle of incidence with the bottom 15 refracting layer 38 includes variable angle facets 42.
`These facets 42 have facet angles and/or curvature
`surface 16 is less than the critical angle characteristic of
`which are varied with position across the facet array to
`the interface between the wedge layer 12 and the first
`focus output light in a desired manner. Curved facets
`layer 28, the light 24 is coupled into the first layer 28.
`would enable producing a softly focused region within
`Therefore, the first layer 28 and the associated optical
`interface properties form an angular ftlter allowing the 20 which the entire viewing screen appears to be illumi-
`nated. Examples of the application to compute screen
`light 24 to pass when the condition is satisfied: 8<8c-
`illumination will be described hereinafter. In FIGS. 2J
`=sin -I (n2/n1). That is, the described critical angle is
`and 2K are shown, respectively, a single refracting
`higher than for the interface between air and the wedge
`prism element 43 and the prism element 43 with an
`layer 12. Therefore, if the two critical angles differ by
`more than 6cj>, nearly all of the light 24 will cross into 25 integral lens 44 to focus the output light. FIGS. 2L and
`the interface between the wedge layer 12 and the first M show the faceted surface 34 with the facets angularly
`disposed to control the output distribution of light. In
`layer 28 before it can exit the wedge layer 12 through
`FIGS. 2K and 2L the light is output to a focal point
`the top surface 14. Consequently, if the two critical
`"F", while in FIG. 2M the output is over an approxi-
`angles differ by less than cj>, a substantial fraction, but
`less than half, of the light can exit the top surface 14. If 30 mate viewing range 45. FIGS. 2N and 20 illustrate flat
`reflecting facets 48 and curved reflecting facet 49 for
`the two angles differ by more than cj> and less than 6cj>,
`providing a collimated light output or focused light
`then substantially more than half but less than all the
`output, respectively.
`light will cross into the wedge layer 12 and the first
`As shown in FIGS. 2A and C the faceted surface 34
`layer 28 before it can exit the wedge layer 12 through
`the top surface 14. The device 10 can thus be con- 35 optically reflects and redirects light 29 through the
`second layer 30, the first layer 28 and then through the
`structed such that the condition 8 <~cis _satisfied ~rst
`wedge layer 12 into ambient. Only a fraction of each
`for _the bottom surface 16. The esca~mg hght 24 (hght
`facet is illuminated, causing the output to appear alter-
`whtch has entered the layer 28) wtll then enter. the
`second layer 30 as long a~ n3 > n2, _for exa~ple. The hght
`nately light and dark when viewed on a sufficiently
`24 then beco~es a col~tmated hght 25 m the sec~nd 40 small scale. Since this pattern is typically undesirable,
`for the preferred embodiment shown in FIG. 2B the
`layer 30 provtded by vtrtue of the first ~ayer 28 bemg
`period of spacing between each of the faceted surfaces
`cou~led t? the wedge la~er _12 and havm~ the proper
`34 is preferably large enough to avoid diffraction ef-
`relattOnshtp between the mdtces of refr~ctton.
`fects, but small enough that the individual facets are not
`1~ order to generate an outpu~ of the hght 24 from the
`de~tce ~0, the second la~er 30 mcludes mea~s for scat- 45 detected by the intended observing means. The spacing
`is also chosen to avoid forming Moire interference pat-
`tenng hght, such as a pamt Ia~er 33 shown m FIG. 2E
`terns with any features of the device to be illuminated,
`or a fac.eted surface 34 shown m both FIGS: 2B and ~C.
`such as a liquid crystal display or CCD (charge coupled
`Th~ pamt layer 33 ~an b~ used to. preferentt~lly proJect
`device) arrays. Some irregularity in the spacing can
`an tmage o! other ~tsual mformatton. The ~am_t la~er 33
`can ~ompnse: for example,_ a ~o~tr?llable dtstnb~tton of 50 mitigate undesirable diffraction Moire effects. For typi-
`cal backlighting displays, a spacing period of roughly
`parttcles hav~g chara~tens~tc mdtces of refractt.on.
`0.001-0.003 inches can accomplish the desired purpose.
`By appropnate chmce, hght can al_so be re~trected
`The faceted surface 34 in FIGS. 2B and 2C, for exam-
`back through the wedge layer 12 and mto ~btent ~see
`pie, can be generally prepared to control the angular
`ligh~ 29 in FIGS. 2A and 2C) or outp_ut dtre~~ly mto
`ambtent from the second layer 30 (see hght 29 m FIG. 55 range over which the redirected light 29 is output from
`the device 10. The minimum distribution of output
`.
`.
`2F).
`angle in the layer 30 has a width which is approximately
`In oth~r forms _of the inventton a furt~er plurahty of
`t .
`layers wtth assoctated "n" values can