LGD_001023
`
`LG Display Ex. 1028
`
`

`
`5,828,488
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`
`
`
`
`‘
`
`LGD_001024
`
`....................... .. 264/171
`2/1971 Schrenk et al.
`3,565,985
`8/1971 Smith .................................... .. 250/199
`3,600,587
`10/1971 Rogers ..... ..
`.. 350/157
`3,610,729
`3/1972 Schrenk etal.
`.. 161/165
`3,647,612
`1/1973 Alfrey, Jr. et al.
`350/1
`3,711,176
`7/1973 Schrenk ................................ .. 425/131
`3,746,485
`9/1973 Schrenk etal.
`....................... .. 425/131
`3,759,647
`11/1973 Schrenk ....... ..
`.. 264/171
`3,773,882
`4/1974 Schrenk et al.
`N 161/181
`3,801,429
`11/1974 Chisholm ..... ..
`.. 65/99A
`3,847,585
`5/1977 Nagy etal.
`............................. 428/350
`4,025,688
`6/1978 Alfrey, Jr. et al.
`................... .. 264/171
`4,094,947
`2/1980 Mohler ......... ..
`.. 340/705
`4,190,832
`7/1980 Castleberry ............................... 362/19
`4,212,048
`.................. .. 260/23 ST
`3/1981 sperling et al.
`4,254,002
`
`.. 350/337
`5/1981 oshirna etal.
`4,268,127
`.......................... 428/212
`1/1982 Cooper et al.
`4,310,584
`2/1982 McKnight et al.
`..................... 340/784
`4,315,258
`
`N 428/332
`1/1984 Aizawa et al.
`4,427,741
`.......................... 528/348
`5/1984 Rogers etal.
`4,446,305
`5/1985 Rogers etal.
`.......................... 528/331
`4,520,189
`
`.. 528/363
`6/1985 Rogers et al.
`4,521,588
`.......................... 428/212
`6/1985 Rogers etal.
`4,525,413
`................................. 428/220
`9/1985 Im etal.
`4,540,623
`
`.. 362/330
`9/1985 Whitehead .
`4,542,449
`........................ .. 350/337
`5/1986 Umeda etal.
`4,586,790
`5/1986 Kawakamietal.
`.................. .. 428/216
`4,590,119
`
`N 350/337
`2/1987 Hosonuma etal.
`4,643,529
`4/1987 Rogers et al.
`........................... 264/1.3
`4,659,523
`4/1987 Nosker .............................. .. 350/339 D
`4,660,936
`
`N 350/345
`7/1987 Ohm et al.
`4,678,285
`7/1988 Utsumi .................................. .. 428/220
`4,756,953
`4,791,540 12/1988 Dreyer, Jr. et al.
`................... .. 362/331
`
`.. 350/337
`4,796,978
`1/1989 Tanaka etal.
`1/1989 Van Raalte ............................ .. 350/345
`4,798,448
`4,799,772
`1/1989 Utsumi .............................. .. 350/339 R
`
`.. 350/96.28
`4,805,984
`2/1989 Cobb, Jr.
`...... ..
`4/1989 Nakamura etal.
`..................... .. 524/89
`4,824,882
`4,840,463
`6/1989 Clark et al.
`........................ .. 350/350 s
`
`. 350/276 R
`4,883,341
`11/1989 Whitehead
`..................... .. 350/96.33
`4,896,942
`1/1990 Onstott et al.
`4,896,946
`1/1990 Suzukletal.
`......................... .. 350/336
`
`4,906,068
`3/1990 olson etal.
`. 350/96.3
`........................ .. 350/335
`4,917,465
`4/1990 Conner et al.
`4,937,134
`6/1990 Schrenk etal.
`....................... .. 428/213
`.. 350/102
`4,952,023
`8/1990 Bradshaw et al.
`
`12/1990 solornon ............................... .. 350/399
`4,974,946
`4,989,076
`1/1991 Owada et al.
`.......................... .. 358/61
`5,009,472
`4/1991 Morimoto ..
`350/6.5
`5,042,921
`8/1991 Sato et al.
`............................... .. 359/40
`5,056,888 10/1991 Messerly etal.
`..................... .. 385/123
`5,056,892 10/1991 Cobb, Jr.
`......... ..
`.. 359/831
`5,059,356
`10/1991 Nakamura etal.
`.. 252/585
`5,061,050 10/1991 ognra ........... ..
`.. 359/490
`5,089,318
`2/1992 Shetty et al.
`.. 428/212
`..
`5,093,739
`3/1992 Aida et al.
`359/73
`OTHER PUBLICATIONS
`5,094,788
`3/1992 Schrenk et al.
`.. 264/171
`.
`.
`“
`5,094,793
`3/1992 Schrenk et al.
`.. 264/171
`Schrenk et al, CoeXtrudedElastorner1c Optical Interference
`5,095,210
`3/1992 Wheatley et al.
`N 250/339
`Film”, SPE Annual Technlcal Conference,Atlanta, Georgia,
`5,103,337
`4/1992 schrenk et al.
`N 359/359
`1703—7 (1988).
`5,122,905
`6/1992 Wheatley et al.
`.. 359/586
`Schenk et al, “CoeXtruder Infrared Reflecting Filrns”, 7th
`5,122,906
`6/1992 Wheatley ..... ..
`.. 359/586
`Annual Meeting Polymer Processing Society Hamilton,
`3424341
`6/1992 Oilslhii---------
`~- 3:9/45187
`7
`,126,880
`6/1992 W eat ey eta.
`.. 3 9/ 87
`5’134’516
`7/1992 Lehureau 9191'
`" 350/301 S)61lT::h(T;, in Coextrusion”, Advances In
`5,138,474
`8/1992 Arakawa
`350/73
`P01
`P
`.
`N
`01
`L .
`.
`A
`1991
`5,139,340
`8/1992 Okumura .......
`359/63
`Y11161
`1°"655111g7
`6W 1661157
`°1115161167( P17
`.)~
`5,149,578
`9/1992 Wheatley et al.
`N 428/213
`Wu et al, “High Transparent Sheet Polarlzer Made With
`5,157,525
`10/1992 Kondo er a1.
`359/53
`Birefringent Materials”, Jpn. J. App. Phys., Vol. 34, part 2,
`5,159,478 10/1992 Akiyama et al.
`....................... .. 359/69
`N0. 8A, pp. L997—999, Aug. 1995.
`
`11/1992 Ota et al.
`2/1993 Arakawa
`3/1993 Akatsuka et al.
`4/1993 Karasawa etal,
`4/1993 Schrenk et al.
`4/1993 Arego etal.
`6/1993 Schrenk ..
`6/1993 Faris ......... ..
`8/1993 Wheatley et al.
`8/1993 Wheat1eYeta1~
`8/1993 Takahashi
`.... ..
`8/1993 M11161:
`
`1971333 21,6611111116t161~
`5
`5
`~
`6E6 61Y6 6~1~~~
`~~ 3 9/ 86
`11/1993 W 6616Y616
`~~ 264/171
`12/1993 R611161161116116161
`359/40
`/1994 K61666“’6 6161
`~~ 359/359
`1/1994 W1166116Y6161
`~~ 252/585
`2/1994 1161161111116 6161
`~ 359/487
`3/1994 K611111116 6161 ~
`.. 359/495
`4/1994 Blanchard et al.
`~~ 369/110
`5/1994 181116111 61 61
`~~ 264/13
`2/1994 861116111‘
`359/53
`/1994 W1116116161
`~ 35%;
`3133:
`¥11C11611t~~~~1~~~~
`5
`8/1994 R6d.6.f1 6'1
`3 9/49
`11 161 616~
`~~ 359/359
`8/1994 W1166116Y6161
`315/1693
`9/1994 K661161‘ 6161
`.. 385/146
`10/1994 Taletal.
`~~ 428/216
`117133;‘
`31611116 6161
`362/31
`6161161111
`.. 264/171
`2/1995 Lewis et al.
`~ 359/487
`6/1995 W61161 ~~~~~~~~~~ ~
`~~ 359/584
`9/1995 861116111‘ 6161
`~~ 428/195
`9/1995 511611Y 6161
`~~ 359/498
`1/1996 561116111‘ 6161
`~ 428/212
`7/1996 561116111‘
`~~~~~~~~~~ ~
`~~ 359/359
`9/1996 W1166116Y6161
`~ 359/638
`9/1996 W61161 ~~~~~~~~~~~~~ ~
`~~ 359/584
`10/1996 561116111‘ 6161
`1/1990 Nosker .............................. .. 350/339 D
`
`
`
`................................ .. 359/73
`. 359/73
`....................... N 359/73
`,,,,,,,,,,,,,,,,,,,,,, .. 359/40
`.. 264/241
`.. 385/146
`.. 428/220
`359/93
`.. 359/359
`428/30
`.. 350/359
`~~ 428/333
`
`5,166,817
`5,189,538
`5,194,975
`5,200,343
`5,202,074
`5,202,950
`5,217,794
`5,221,982
`5,233,465
`5,234,729
`5,237,446
`572387738
`57245733
`57
`7
`72627894
`572637935)
`7
`7
`572787694
`572867418
`572957018
`5,303,083
`573097422
`
`7
`
`7
`
`573397179
`7
`7
`573397198
`573457146
`5,359,691
`57331117653
`7
`7
`5,389,324
`574227756
`574487404
`574517449
`574867949
`575407978
`575527927
`575597634
`575687316
`B1 4,660,936
`
`Japan ............................. .. B02B 5/30
`5/1992
`Japan .
`1 G03B 21/14
`7/1992
`Japan .
`G02B 5/18
`11/1993
`Japan .
`G02B 5/18
`1/1994
`. . . . ..
`Japan . . . . .
`G02B 5/02
`8/1994
`1/1981 United Kingdom
`.. G02F 1/133
`7/1991 WIPO ............ ..
`. B29C 43/20
`5/1994 WIPO
`G02F 1/1335
`12/1994 WIPO
`.. G02F 1/1335
`6/1995 WIPO
`B32B 7/02
`6/1995 WIPO
`G02B 5/30
`6/1995 WIPO
`G02B 5/30
`6/1995 WIPO ......................... .. G02F 1/1335
`
`
`
`4—141603
`4—184429
`5—288910
`6—11607
`6—222207
`2 052 779
`Wo 91/09719
`Wo 94/11776
`Wo 94/29765
`Wo 95/17303
`Wo 95/17691
`Wo 95/17692
`Wo 95/17699
`
`LGD_001024
`
`

`
`5,828,488
`Page 3
`
`Derwent Abstract, JP 63017023.
`Abstract, Japan 62-295024, 1987.
`Abstract, Japan 63-168626, 1988.
`Abstract, Japan 4-356038, 1992.
`Alfrey, Jr. et al., “Physical Optics of Iridescent Multilayered
`Plastic Films”, Polymer Engineering and Science, Vol. 9,
`No. 6, Nov. 1969, pp. 400-404.
`Radford et al., “ReflectiVity of Iridescent Coextruded Mul-
`tilayered Plastic Films”, presented at the American Chemi-
`cal Society Symposium on Coextruded Plastic Films, Fibers,
`Composites, Apr. 9-14, 1972.
`3M IR—Compatible Safelight Kit,
`78-8063-2625-8, Jan. 1989, pp. 1-7.
`3M IR Safelight Brochure, 1991.
`Boese et al., “Chain Orientation and Anisotropies in Optical
`and Dielectric Properties in Thin Films of Stiff Polyimides”,
`Journal of Polymer Science, Part B: Polymer Physics, Vol.
`30, pp. 1321-1327 (1992).
`
`Instruction Sheet
`
`Baba et al., “Optical anisotropy of stretched gold island
`films: experimental results”, Optics Letters, Vol. 17, No. 8,
`Apr. 15, 1992.
`
`Weber, “Retroreflecting Sheet Polarizer”, SID conf. pro-
`ceedings, Boston, MA, May 1992, SID 92 Digest, pp.
`427-429.
`
`Weber, “RetroreflectiVe Sheet Polarizer”, SID conf. pro-
`ceedings, Seattle, WA, May 1993, SID 93 Digest, pp.
`669-672.
`
`Hodgkinson et al., “Effective principal refractive indices and
`column angles for periodic stacks of thin birefringent films”,
`Optical Society ofAmeria, Vol. 10, No. 9, pp. 2065-2071,
`Sep. 1993.
`
`Zang et al., “Giant Anistropies in the Dielectric Properties of
`Quasi-Epitaxial Crystalline Organic Semiconductor Thin
`Films”.
`
`LGD_001025
`
`LGD_001025
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 1 of 32
`
`5,828,488
`
`15
`
`18 20
`
` 23
`E 42
`11 ->
`
`44
`
`12
`
`40
`
`24
`
`32g “L48 —’
`
`__
`
`__
`
`45
`
`__ 8 __
`30 A__
`3463
`
`Fig. 2
`
`LGD_001026
`
`39
`
`LGD_001026
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 2 of 32
`
`5,828,488
`
`17
`
`E
`
`1820
`
`LGD_001027
`
`LGD_001027
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 3 of 32
`
`5,828,488
`
`31
`
`1 O0
`
`80
`
`60
`
`40
`
`20
`
`%T
`
`33
`
`0
`
`400
`
`500
`
`600
`
`700
`
`7\ (nm)
`Flg. 5
`
`LGD_001028
`
`LGD_001028
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 4 of 32
`
`5,828,488
`
`K146
`/|\
`
`164
`
`
`
`242
`Fig. 7
`
`LGD_001029
`
`LGD_001029
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 5 of 32
`
`5,828,488
`
`HEFLECTED
`
`age
`
`226
`
`00
`
`TRANSMITTED
`
`TRANSMITTED
`
`//£3
`
`94°
`
`9.4°
`
`33-4\\
`
`Fig. 8
`
`2(146
`
`164
`
`152 (a,c)
`
`148
`(a,b,c,d)
`
`LGD_001030
`
`150
`
`161(a)
`
`110
`’/
`
`154 (a,b,c,d)
`
`140
`
`156 (b,c,d)
`
`157 (a,b,c,d)
`
`9
`
`LGD_001030
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 6 of 32
`
`5,828,488
`
`146
`
`z:<
`/|\
`
`K__
`
`170
`
`173
`
`172
`
`‘74
`
`Fig. 10
`
`"6
`
`149
`
`147
`
`142
`
`150
`
`110
`
`116
`
`140
`
`175
`
`LGD_001031
`
`LGD_001031
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 7 of 32
`
`5,828,488
`
`160
`
`140
`
`$120
`8
`3100
`.9
`
`Cc?» 80
`.2
`1‘: so
`CD
`0:
`
`40
`
`20
`
`164
`
`162
`
`00 51015 20 25 30 35 40 45 50 55 60 65 70
`Degrees off normal
`Fig. 12
`
`,146
`
`2
`/|\
`
`149
`
`
`
`LGD_001032
`
`LGD_001032
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 8 of 32
`
`5,828,488
`
`LGD_001033
`
`LGD_001033
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 9 of 32
`
`5,828,488
`
`/100
`
`102
`
`104
`
`LGD_001034
`
`LGD_001034
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 10 of 32
`
`5,828,488
`
`0.05
`
`REFLECTIVITY
`
`FIEFLECTIVITY
`
`0.04
`
`0.03
`
`0.01
`
`0.02
`
`010 20 30 40 50 60 70 80 90
`
`ANGLE OF INCIDENCE IN 1.60 MEDIUM
`
`Fig. 16
`
`0.05
`
`0.04
`
`0.03
`
`0.02
`
`0.01
`
`0
`
`10
`
`20 30 40 50 60 70 80 90
`
`ANGLE OF INCIDENCE IN 1.60 MEDIUM
`
`Fig. 17
`
`LGD_001035
`
`LGD_001035
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 11 of 32
`
`5,828,488
`
`0.012
`
`0.01
`
`9 oo oo
`
`REFLECTIVITY 0.004
`
`0.006
`
`0.002
`
`0
`
`010 20 30 40 50 60 70 80 90
`
`ANGLE OF INCIDENCE IN 1.00 MEDIUM
`
`Fig. 18
`
`INDEX
`
`IN-PLANE
`
`INDEX 1
`
`
`
`' INCREASING '
`IN-PLANE
`NO BREWSTER ANGLE,
`I BREWSTER .
`INDEX 2
`|3QTRQp[C I
`ANGLE
`I R INCREASES WITH ANGLE
`CASE
`T
`
`Fig_ 19
`
`NO BREWSTER ANGLE,
`R CONSTANT
`
`LGD_001036
`
`LGD_001036
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 12 of 32
`
`5,828,488
`
`INDEX
`
`
`
`IN-PLANE
`
`INDEX 1
`
`
`
`DECREASING
`BREWSTER
`ANGLE
`
`ISOTHOPIC
`CASE
`
`IN-PLANE
`
`INDEX 2
`
`Fig. 20
`
`INDEX
`
`
` IN-PLANE
`INDEX 1
`
`
`
`
`|N—PLANE
`INDEX 2
`I
`I
`nzz
`
`'SOTROP'C
`CASE
`
`
`
`1
`I
`.
`
`NO BREWSTER
`ANGLE,
`:
`
`INCREASING
`l WNCREASES
`
`BREWSTER
`WITH ANGLE
`
`I
`
`ANGLE
`
`Fig. 21
`
`LGD_001037
`
`LGD_001037
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 13 of 32
`
`5,828,488
`
`1 .0
`
`0.8
`
`
`
`—LOG[1-R] .0.0J5O‘)
`
`0
`
`...--.-......AA.___4Q...
`
`
`
`LAM--.
`
`400
`
`450
`
`500
`
`550
`
`600
`
`650
`
`700
`
`WAVELENGTH (nm)
`
`Fig. 22
`
`0.0001
`
`0.00008
`
`0.00006
`
`0.00004
`
`0.00002
`
`REFLECTIVITY
`
`LGD_001038
`
`0
`
`10 20 30 40 50
`
`60 70 80 90
`
`ANGLE OF INCIDENCE IN 1.00 MEDIUM
`
`Fig. 23
`
`LGD_001038
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 14 of 32
`
`5,828,488
`
`REFLECTIVITY
`
`0.0001
`
`0.00008
`
`0.00006
`
`0.00004
`
`0.00002
`
`0
`
`LGD_001039
`
`‘3
`
`0
`
`10
`
`20 30 40
`
`50
`
`60 70 80 90
`
`ANGLE OF INCIDENCE IN 1.00 MEDIUM
`
`Fig. 24
`
`LGD_001039
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 15 of 32
`
`5,828,488
`
`0.02
`
`0.01
`
`Any
`
`-0.01
`
`-0.02
`-0.075
`
`-0.05
`
`-0.025
`
`0
`
`0.025
`
`0.05
`
`0.075
`
`3
`
`AHZ
`
`Fig. 25
`
`LGD_001040
`
`LGD_001040
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 16 of 32
`
`5,828,488
`
`100
`
`80
`
`60
`
`40%Transmission
`
`20
`
`0
`400
`
`450
`
`500
`
`550
`
`600
`
`650
`
`700
`
`Wave Length (nm)
`
`Fig. 26
`
`LGD_001041
`
`LGD_001041
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 17 of 32
`
`5,828,488
`
`100
`
`80
`
`60
`
`40
`
`20
`
`°/oTransmission
`
`400
`
`450
`
`600
`550
`500
`Wave Length (nm)
`
`650
`
`700
`
`Fig. 27
`
`LGD_001042
`
`LGD_001042
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 18 of 32
`
`5,828,488
`
`100
`
`°/oTransmission
`
`400
`
`450
`
`500
`
`550
`
`600
`
`650
`
`700
`
`Wave Length (nm)
`Fig. 28
`
`LGD_001043
`
`LGD_001043
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 19 of 32
`
`5,828,488
`
`100
`
`80
`
`%Transmission
`
`20
`
`1
`
`400
`
`500
`
`600
`
`700
`
`800
`
`900
`
`1000
`
`1100
`
`Wave Length (nm)
`
`Fig. 29
`
`LGD_001044
`
`LGD_001044
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 20 of 32
`
`5,828,488
`
`100
`
`O)O%Transmission
`
`43-O
`
`20
`
`0
`400
`
`450
`
`500
`
`550
`
`600
`
`650
`
`700
`
`Wave Length (nm)
`
`Fig. 30
`
`LGD_001045
`
`LGD_001045
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 21 of 32
`
`5,828,488
`
`b
`
`a
`
`400
`
`500
`
`600
`
`700
`
`800
`
`Wave Length (nm)
`
`Fig. 31
`
`10
`
`8
`
`C
`
`.9
`.3 5
`
`E 2 E
`
`r— 4
`
`o\°
`
`2
`
`LGD_001046
`
`LGD_001046
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 22 of 32
`
`5,828,488
`
`100
`
`80
`
`a
`
`60%Transmission
`
`20
`
`400
`
`500
`
`600
`
`700
`
`800
`
`Wave Length (nm)
`Fig. 32
`
`LGD_001047
`
`LGD_001047
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 23 of 32
`
`5,828,488
`
`100
`
`80
`
`60
`
`%Transmission 40
`
`20
`
`400
`
`500
`
`600
`
`700
`
`800
`
`Wave Length (nm)
`
`Fig. 33
`
`LGD_001048
`
`LGD_001048
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 24 of 32
`
`5,828,488
`
`100
`
`80
`
`%Transmission
`
`400
`
`500
`
`600
`
`700
`
`800
`
`Wave Length (nm)
`
`Fig. 34
`
`LGD_001049
`
`LGD_001049
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 25 of 32
`
`5,828,488
`
`100
`
`80
`
`60
`
`20
`
`°/oTransmission
`
`400
`
`500
`
`600
`
`700
`
`800
`
`Wave Length (nm)
`
`Fig. 35
`
`LGD_001050
`
`LGD_001050
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 26 of 32
`
`5,828,488
`
`100
`
`80
`
`60%TRANSMISSION
`
`20
`
`400
`
`5 8
`
`7 600
`
`700
`
`300
`
`WAVE LENGTH (nm)
`
`Fig. 36
`
`LGD_001051
`
`LGD_001051
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 27 of 32
`
`5,828,488
`
`0C@
`
`CCI
`
`N
`
`E 5 I
`
`§:sl~
`zcra
`UJO
`‘U0
`gm
`<3!
`3
`
`C)
`
`CI
`
`D
`
`CCV
`
`‘
`
`LGD_001052
`
`LGD_001052
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 28 of 32
`
`5,828,488
`
`100
`
`90
`
`a
`
`%TRANSMISSION
`
`0 ,_,
`
`4oo
`
`500
`
`eoo
`
`7oo
`
`soo
`
`WAVE LENGTH (nm)
`
`Fig. 38
`
`LGD_001053
`
`LGD_001053
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 29 of 32
`
`5,828,488
`
`100
`
`80
`
`O)O%TRANSMISSION 4so
`
`20
`
`400
`
`500
`
`600
`
`700
`
`800
`
`WAVE LENGTH (nm)
`
`Fig. 39
`
`LGD_001054
`
`LGD_001054
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 30 of 32
`
`5,828,488
`
`100
`
`80
`
`b
`
`a
`
`C
`
`500
`
`600
`
`700
`
`800
`
`Wave Length (nm)
`
`Fig. 40A
`
`S
`'7: 60
`.2
`E(D
`
`C E
`
`}—
`8 4o
`
`20
`
`O
`400
`
`LGD_001055
`
`LGD_001055
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 31 of 32
`
`5,828,488
`
`100
`
`80
`
`%Transmission-bO)OO
`
`20
`
`0
`400
`
`LGD_001056
`
`O
`
`500
`
`600
`
`700
`
`800
`
`Wave Length (nm)
`Fig. 40B
`
`LGD_001056
`
`

`
`U.S. Patent
`
`Oct. 27, 1998
`
`Sheet 32 of 32
`
`5,828,488
`
`100
`
`80
`
`“L
`
`b
`
`a
`
`S
`‘:7: 60
`.1’
`EU)
`
`C EI
`
`-
`
`c
`
`500
`
`600
`Wave Length (nm)
`
`700
`
`800
`
`Fig. 40C
`
`o\° 40
`
`20
`
`0
`400
`
`LGD_001057
`
`LGD_001057
`
`

`
`1
`REFLECTIVE POLARIZER DISPLAY
`
`2
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`5,828,488
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`This is a continuation in part of U.S. patent application 5
`Ser. Nos. 08/171,239 and 08/172,593, which were filed Dec.
`21, 1993, now abandoned and is a continuation in part of
`U.S. patent application Ser. Nos. 08/359,436 and 08/360,
`204, which were filed Dec. 20, 1994, now abandoned all of
`which are incorporated herein by reference.
`
`10
`
`TECHNICAL FIELD
`
`The invention is an improved optical display.
`
`BACKGROUND
`
`Optical displays are widely used for lap-top computers,
`hand-held calculators, digital watches and the like. The
`familiar liquid crystal (LC) display is a common example of
`such an optical display. The conventional LC display locates
`a liquid crystal and an electrode matrix between a pair of
`absorptive polarizers. In the LC display, portions of the
`liquid crystal have their optical state altered by the applica-
`tion of an electric field. This process generates the contrast
`necessary to display “pixels” of information in polarized
`light.
`For this reason the traditional LC display includes a front
`polarizer and a rear polarizer. Typically, these polarizers use
`dichroic dyes which absorb light of one polarization orien-
`tation more strongly than the orthogonal polarization orien-
`tation. In general, the transmission axis of the front polarizer
`is “crossed” with the transmission axis of the rear polarizer.
`The crossing angle can vary from zero degrees to ninety
`degrees. The liquid crystal,
`the front polarizer and rear
`polarizer together make up an LCD assembly.
`LC displays can be classified based upon the source of
`illumination. “Reflective” displays are illuminated by ambi-
`ent light that enters the display from the “front.” Typically
`a brushed aluminum reflector is placed “behind” the LCD
`assembly. This reflective surface returns light to the LCD
`assembly while preserving the polarization orientation of the
`light incident on the reflective surface.
`It is common to substitute a “backlight” assembly for the
`reflective brushed aluminum surface in applications where
`the intensity of the ambient light is insufficient for viewing.
`The typical backlight assembly includes an optical cavity
`and a lamp or other structure that generates light. Displays
`intended to be viewed under both ambient light and backlit
`conditions are called “transflective.” One problem with
`transflective displays is that the typical backlight is not as
`efficient a reflector as the traditional brushed aluminum
`
`surface. Also the backlight randomizes the polarization of
`the light and further reduces the amount of light available to
`illuminate the LC display. Consequently, the addition of the
`backlight to the LC display makes the display less bright
`when viewed under ambient light.
`Therefore, there is a need for a display which can develop
`adequate brightness and contrast under both ambient and
`backlight illumination.
`
`SUMMARY
`
`The optical display of the present invention comprises
`three basic elements. The first element is a reflective polar-
`izer. This reflective polarizer is located between a liquid
`crystal display (LCD) assembly and an optical cavity, which
`comprise the second and third elements respectively.
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`The drawings depict representative and illustrative imple-
`mentations of the invention. Identical reference numerals
`
`refer to identical structure throughout the several figures,
`wherein:
`
`FIG. 1 is a schematic cross section of an optical display
`according to the invention;
`FIG. 2 is a schematic cross section of an illustrative
`
`optical display according to the invention;
`FIG. 3 is a schematic cross section of an illustrative
`
`optical display according to the invention;
`FIG. 4 is an exaggerated cross sectional view of the
`reflective polarizer of the invention;
`FIG. 5 shows the optical performance of the multilayer
`reflective polarizer of Example 2;
`FIG. 6 is a schematic diagram of an optical display
`according to the invention with brightness enhancement;
`FIG. 7 is a diagram illustrating the operation of a bright-
`ness enhancer;
`FIG. 8 is a graph illustrating the operation of a brightness
`enhancer;
`FIG. 9 is a schematic cross section of an illustrative
`
`optical display;
`FIG. 10 is a schematic cross section of an illustrative
`
`optical display;
`FIG. 11 is a schematic cross section of an illustrative
`
`optical display;
`FIG. 12 is a graph of test results;
`FIG. 13 is a schematic cross section of an illustrative
`
`optical display;
`FIG. 14 is a schematic cross section of a brightness
`enhanced reflective polarizer;
`FIG. 15 shows a two layer stack of films forming a single
`interface.
`
`FIGS. 16 and 17 show reflectivity versus angle curves for
`a uniaxial birefringent system in a medium of index 1.60.
`FIG. 18 shows reflectivity versus angle curves for a
`uniaxial birefringent system in a medium of index 1.0.
`FIGS. 19, 20 and 21 show various relationships between
`in-plane indices and z-index for a uniaxial birefringent
`system.
`FIG. 22 shows off axis reflectivity versus wavelength for
`two different biaxial birefringent systems.
`FIG. 23 shows the effect of introducing a y-index differ-
`ence in a biaxial birefringent film with a large z-index
`difference.
`
`FIG. 24 shows the effect of introducing a y-index differ-
`ence in a biaxial birefringent film with a small z-index
`difference.
`
`FIG. 25 shows a contour plot summarizing the informa-
`tion from FIGS. 18 and 19;
`FIGS. 26-31 show optical performance of multilayer
`mirrors given in Examples 3-6;
`FIGS. 32-36 show optical performance of multilayer
`polarizers given in Examples 7-11;
`FIG. 37 shows optical performance of the multilayer
`mirror given in Example 12;
`FIG. 38 shows optical performance of the AR coated
`polarizer given in Example 13;
`FIG. 39 shows optical performance of the polarizer given
`in Example 14; and
`
`LGD_001058
`
`LGD_001058
`
`

`
`5,828,488
`
`3
`FIGS. 40A—40C show optical performance of multilayer
`polarizers given in Example 15 .
`
`DETAILED DESCRIPTION
`
`FIG. 1 is a schematic diagram of an illustrative optical
`display 10 that includes three principle components. These
`include the polarizing display module shown as LCD assem-
`bly 16, a reflective polarizer 12, and an optical cavity 24.
`The LCD assembly 16 shown in this figure is illuminated
`by polarized light provided by the reflective polarizer 12 and
`the optical cavity 24.
`Ambient light incident on the display 10, depicted by ray
`60 traverses the LCD module 16, the reflective polarizer 12
`and strikes the diffuse reflective surface 37 of the optical
`cavity 24. Ray 62 depicts this light as it is reflected by the
`diffusely reflective surface 37 toward the reflective polarizer
`12.
`
`Light originating from within the optical cavity 24 is
`depicted by ray 64. This light is also directed toward the
`reflective polarizer 12 and passes through the diffusely
`reflective surface 37. Both ray 62 and ray 64 have light
`exhibiting both polarization states (a,b).
`FIG. 2 shows a schematic optical display 11 illustrated
`with a three layer LCD assembly 15 that includes a front
`polarizer 18, a liquid crystal 20 and a rear polarizer 23. In
`this embodiment the optical cavity 24 is an edge lit backlight
`which includes a lamp 30 in a reflective lamp housing 32.
`Light from the lamp 30 is coupled to the light guide 34
`where it propagates until it encounters a diffuse reflective
`structure such as spot 36. This discontinuous array of spots
`is arranged to extract lamp light and direct it toward the LCD
`module 15. Ambient light entering the optical cavity 24 may
`strike a spot or it may escape from the light guide through
`the interstitial areas between spots. The diffusely reflective
`layer 39 is positioned below the light guide 34 to intercept
`and reflect such rays. In general, all the rays that emerge
`from the optical cavity 24 are illustrated by ray bundle 38.
`This ray bundle is incident on the reflective polarizer 12
`which transmits light having a first polarization orientation
`referred to as “(a)” and effectively reflects light having the
`orthogonal polarization orientation
`Consequently, a cer-
`tain amount of light, depicted by ray bundle 42, will be
`transmitted by the reflective polarizer 12 while a substantial
`amount of the remaining light will be reflected as indicated
`by ray bundle 40. The preferred reflective polarizer material
`is highly efficient and the total losses due to absorption
`within the reflective polarizer 12 are very low (on the order
`of 1 percent). This lost light is depicted by ray bundle 44.
`The light having polarization state (b) reflected by the
`reflective polarizer 12 reenters the optical cavity 24 where it
`strikes the diffusely reflective structures such as spot 36 or
`the diffusely reflective layer 39. The diffusely reflective
`surfaces serve to randomize the polarization state of the light
`reflected by the optical cavity 24. This recirculation and
`randomization process is depicted as path 48. The optical
`cavity 24 is not a perfect reflector and the light losses in the
`cavity due to scattering and absorption are depicted by ray
`bundle 46. These losses are also low (on the order of 20
`percent). The multiple recirculations effected by the combi-
`nation of the optical cavity 24 and the reflective polarizer 12
`form an efficient mechanism for converting light from state
`(b) to state (a) for ultimate transmission to the viewer.
`The effectiveness of this process relies on the low absorp-
`tion exhibited by the reflective polarizer disclosed herein
`and the high reflectivity and randomizing properties exhib-
`ited by many diffusely reflective surfaces. In FIG. 2 both the
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4
`discontinuous layer depicted by spot 36 and the diffusely
`reflective continuous layer 39 may be formed of a titanium
`oxide pigmented material. It should be appreciated that a
`diffuse reflective surface 37 (shown in FIG. 1) can be formed
`of transparent surface textured polycarbonate. This material
`could be placed above the light guide 34 to randomize
`incident light in the configuration shown in FIG. 2. The
`specific and optimal configuration will depend on the par-
`ticular application for the completed optical display.
`In general, the gain of the system is dependent on the
`efficiency of both the reflective polarizer body 12 and the
`optical cavity 24. Performance is maximized with a highly
`reflective optical cavity 24 consistent with the requirement
`of randomization of the polarization of incident light, and a
`very low loss reflective polarizer 12.
`FIG. 3 shows a schematic optical display 14 illustrated
`with a two layer LCD assembly 17 that includes a front
`polarizer 18 and a liquid crystal 20. In this embodiment the
`optical cavity 24 includes an electroluminescent panel 21.
`The traditional electroluminescent panel 21 is coated with a
`phosphor material 19 that generates light when struck by
`electrons and that is also diffusely reflective when struck by
`incident
`light. Usually, electroluminescent displays are
`“grainy” because of the variations in efficiencies associated
`with the phosphor coating. However, light returned by the
`reflective polarizer 12 has a tendency to “homogenize” the
`light emissions and improve overall uniformity of illumina-
`tion exhibited by the optical display 14. In the illustrative
`optical display 14 the LCD assembly 17 lacks a rear polar-
`izer. In this optical display 14 the reflective polarizer 12
`performs the function normally associated with the rear
`polarizer 23 shown in optical display 11 in FIG. 2.
`FIG. 4 is a schematic perspective diagram of a segment of
`the reflective polarizer 12. The figure includes a coordinate
`system 13 that defines X, Y and Z directions that are referred
`to in the description of the reflective polarizer 12.
`The illustrative reflective polarizer 12 is made of alter-
`nating layers (ABABA .
`.
`. ) of two different polymeric
`materials. These are referred to as material “(A)” and
`material “(B)” throughout the drawings and description. The
`two materials are extruded together and the resulting mul-
`tiple layer (ABABA. .
`. ) material is stretched (5:1) along
`one axis (X), and is not stretched appreciably (1:1) along the
`other axis
`The X axis is referred to as the “stretched”
`direction while the Y axis is referred to as the “transverse”
`direction.
`
`index of refraction
`The (B) material has a nominal
`(n=1.64 for example) which is not substantially altered by
`the stretching process.
`The (A) material has the property of having the index of
`refraction altered by the stretching process. For example, a
`uniaxially stretched sheet of the (A) material will have one
`index of refraction (n=1.88 for example) associated with the
`stretched direction and a different
`index of refraction
`
`(n=1.64 for example) associated with the transverse direc-
`tion. By way of definition, the index of refraction associated
`with an in-plane axis (an axis parallel to the surface of the
`film) is the effective index of refraction for plane-polarized
`incident light whose plane of polarization is parallel to that
`axis.
`
`Thus, after stretching the multiple layer stack
`(ABABA .
`.
`. ) of material shows a large refractive index
`difference between layers (delta n=1.88—1.64=0.24) associ-
`ated with the stretched direction. While in the transverse
`
`direction, the associated indices of refraction between layers
`are essentially the same (delta n=1.64—1.64=0.0). These
`
`LGD_001059
`
`LGD_001059
`
`

`
`5,828,488
`
`5
`optical characteristics cause the multiple layer laminate to
`act as a reflecting polarizer that will transmit the polarization
`component of the incident light that is correctly oriented
`with respect to the axis 22. This axis is defined as the
`transmission axis 22 and is shown in FIG. 4. The light which
`emerges from the reflective polarizer 12 is referred to as
`having a first polarization orientation (a).
`The light that does not pass through the reflective polar-
`izer 12 has a polarization orientation (b) that differs from the
`first orientation (a). Light exhibiting this polarization orien-
`tation (b) will encounter the index differences which result
`in reflection of this light. This defines a so-called “extinc-
`tion” axis shown as axis 25 in FIG. 4. In this fashion the
`
`reflective polarizer 12 transmits light having a selected
`polarization (a) and reflects light having the polarization
`Although the reflective polarizer 12 has been discussed
`with an exemplary multiple layer construction which
`includes alternating layers of only two materials it should be
`understood that
`the reflective polarizer 12 may take a
`number of forms. For example, additional types of layers
`may be included into the multiple layer construction. Also in
`a limiting case, the reflective polarizer may include a single
`pair of layers
`one of which is stretched. Furthermore,
`a dichroic polarizer could be bonded directly to reflective
`polarizer 12.
`Another important property of the optical cavity 24 is the
`fact that polarization randomization process associated with
`the cavity will also alter the direction of the incident light.
`In general, a significant amount of light exits the optical
`cavity off-axis. Consequently, the path of such light in the
`reflective polarizer is longer than the path length for near
`normal light. This effect must be addressed to optimize the
`optical performance of the system. The reflective polarizer
`body 12 described in the example is capable of broadband
`transmission into the longer wavelengths which is desirable
`to accommodate off-axis rays. FIG. 5 shows trace 31 which
`indicates a transmissivity of over 80 percent over a wide
`range of wavelengths. Trace 33 shows efficient broadband
`reflectively over a large portion of the visible spectrum. The
`optimal reflectivity trace would extend into the infrared and
`extend from approximately 400 nm to approximately 800
`nm.
`
`In another embodiment, the apparent brightness of the
`display may be increased by the use of a brightness enhance-
`ment film. FIG. 6 shows an optical display 164 which has
`three primary components. These are the optical display
`module 142, the brightness enhanced reflective polarizer 110
`and the optical cavity 140. Typically the complete optical
`display 164 will be planar and rectangular in plan view as
`seen by observer 146 and will be relatively thin in cross
`section with the three primary components in close prox-
`imity to each other.
`In use, the display module 142 is illuminated by light
`processed by the brightness enhanced reflective polarizer
`110 and the optical cavity 140. Together these two compo-
`nents direct polarized light into a viewing zone 136 shown
`schematically as an angle. This light is directed through the
`display module 142 toward the observer 146. The display
`module 142 will typically display information as pixels.
`Polarized light transmission through a pixel is modulated by
`electrical control of the birefringence of the liquid crystal
`material. This modulates the polarization state of the light,
`affecting its relative absorption by a second polarizer layer
`that forms a part of the display module 142.
`There are two sources for illumination shown in the
`
`6
`light passes through the display module 142 and brightness
`enhanced reflective polarizer 110 and is incident on the
`optical cavity 140. The optical cavity reflects this light as
`indicated by ray 165. The second source of light may be
`generated within the optical cavity itself as depicted by ray
`163. If the optical cavity 140 is a backlight then the principal
`source of illumination originates within the optical cavity
`140 and the optical display is referred to as “backlit.” If the
`principal source of illumination is ambient light represented
`by ray 162 and ray 165 then the optical display is called
`“reflective” or “passive.” If the display is to be viewed under
`both ambient and cavity generated light the display is called
`“transflective.” The present invention is useful in each of
`these display types.
`the brightness
`Regardless of the origin of the light,
`enhanced reflective polarizer 110 and the optical cavity 140
`cooperate together to “recirculate” light so that the maxi-
`mum amoun