United States Patent [19J
`Shimizu et al
`
`1111111111111111I 11111 lllll lllll lllll 111111111111111 11111 11111111111111111I
`US005998925A
`[11) Patent Number:
`L45J Date of Patent:
`
`5,998,925
`Dec. 7, 1999
`
`[54] UGHT EMITTING DEVlCE HAVfNG A
`NITRIDE COMPOUND SEMICONDUCTOR
`AND A PHOSPHOR CON1J\.INING A
`GARNET FLUORESCENT MATERrAL
`
`[75J Lnventors: Yosbinori Shimizu, Naka-gun; Kensbo
`akano, Ana(cid:143) ; Yasunobu Noguchi,
`Naka-gu(cid:143) ; Toshio Moriguchi, Ana(cid:143), all
`of Japan
`
`[73] Assignee: Nich.ia Kagaku Kogyo Kabusbiki
`Kaisha, Toh shima, Japan
`
`[21] Appl. No.: 08/902,725
`
`[22]
`
`[30)
`
`.Jul. 29, 1997
`Filed :
`Foreign Application Priority Data
`
`Jul. 29 1996
`Sep. l 7, 1996
`Sep. 18, 1996
`Dec. 27, 1996
`Mar. 3J, 1997
`
`[JP]
`[JP[
`[JP)
`[JP]
`[JPI
`
`Japa n .................... ................ 8-198585
`Japan ................. , .. ................ 8-244339
`Japa n .................................... 8-245381
`Japan ................................ .... 8-359004
`Japan .......... .......... ................ 9-0810IO
`
`.. ..... ...... ................... HOU 1/62; HOU 63/04
`Int. Cl.6
`[51]
`[52] U.S. Cl . ...... ................... 313/503; 313/498; 313/501;
`313/502; 257/103
`[58] Field of Search ..................................... 313/498, 503,
`313/501, 502; 257/103
`
`[56)
`
`References Cited
`
`U. . PJXTENT OOCUMEN1
`
`3,699,478 10/1972 Pinnow cl al. ....................... .. 332/7.5 1
`4,298,820 11/1981 Bongers et al. .
`2/ 1988 Van Kemenade et al. .
`4,727,283
`8/1998 Nitta ...................................... .. 257/103
`5,798,537
`
`FOREIGN PATENT DOCUMENTS
`
`50-439 I 3
`
`4/J 975
`
`Japan .
`
`55-4898
`62-20237
`1-179471
`5-152609
`7-099345
`7- 176794
`8-007614
`9-027642
`
`1/ 1980
`l/ L987
`711989
`6/1993
`4/ [995
`7/ 1995
`1/1996
`1/ 1997
`
`Japa n .
`Japa n .
`Japan .
`Japan .
`Japa n .
`Japa n .
`Japan .
`Japa n .
`
`OTH ER PUBLICATIONS
`
`" A New Phosphor fo r Frying-Spot Cathode-Ray Tubes fo r
`olor Television: Yellow-Eminiog Y 3al 5O12-Ce3+", G.
`Glasse et al., Applied Physic Leuers, vol. 11, No. 2, pp.
`53-54 (1967).
`"Improved color rcoclitio(cid:143) in hig h pressure mercury vapor
`lamps", Mary V. Hoffman, Journal of IES, pp . 89-91 (1 977).
`S. Nakamura, SPIE, 3002:26-35 (1997).
`
`Primary Examiner-Yip Patel
`Assistant Examiner-M ichael] . Smith
`Allorney, Agent, or Firm-Birch, Stewart, Kolasch & Birch,
`LLP
`
`[57]
`
`ABSTRACT
`
`The whi te light emitting diode comprising a light cmi tli(cid:143) g
`component u iog a se micoaductor a a lig ht emilling layer
`and a phosphor which absorbs a part of lig ht e millecl by tbe
`light emi tring compo nent and emits light of waveleng th
`cliffcrc(cid:143) t fro m tbat of the absorbed light, wherein the lig ht
`emitt ing layer of the light emitli(cid:143) g compo(cid:143) e(cid:143)
`t is a o.i tricle
`compound semiconductor and Lhe phosphor cont ains ga met
`fl uoresceat materi al activated with cerium which contains at
`least o(cid:143) e clement selected fro m the group consisting of Y,
`Lu, Sc, La, Gd a(cid:143) cl Sm, a(cid:143) cl at least one cleme nt selected
`from the group consisting of Al, Ga a(cid:143) cl I(cid:143) a(cid:143) cl , a(cid:143) cl is
`subject to le. s deterioration of emission characteristic even
`when u eel with bigh luminance fo r a loag period of time.
`
`23 Claims, 19 Drawing beets
`
`101
`
`TCL 1037, Page 1
`LOWES 1037, Page 1
`VIZIO Ex. 1037 Page 0001
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 1 of 19
`
`5,998,925
`
`Fig.1
`
`100
`
`101
`
`104
`
`102
`
`105a} 105
`105b
`
`Fig.2
`200
`
`204
`
`205
`
`TCL 1037, Page 2
`LOWES 1037, Page 2
`VIZIO Ex. 1037 Page 0002
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 2 of 19
`
`5,998,925
`
`Fig.3A
`
`100 r--,
`
`\
`•
`
`Relative 50
`intensity
`
`(%)
`
`'
`
`I..._
`
`0
`200
`
`I
`
`'
`
`I
`
`J
`
`,
`
`._
`
`I
`
`'
`"'
`
`\
`
`' ....
`500
`
`Wavelength ().)
`
`.....
`
`I
`
`\
`
`I/
`
`"
`'
`
`400
`300
`Excitation spectrum
`
`Fig.38
`100
`
`Relative
`intensity 50
`(%)
`
`0
`400
`
`~
`
`I
`
`...
`
`~
`
`" II,.
`
`' I\
`
`' 1,
`"
`
`~
`\.
`
`' I\.
`
`J
`I/
`
`j
`
`.I
`
`I
`
`II
`
`I.I
`' II
`
`....
`
`500
`600
`Emission spectrum
`
`700
`Wavelength ( ). )
`
`TCL 1037, Page 3
`LOWES 1037, Page 3
`VIZIO Ex. 1037 Page 0003
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 3 of 19
`
`5,998,925
`
`I
`J V 0 co co
`/
`
`0
`('I') co
`
`I I
`
`........
`E
`
`C -
`.c -O>
`
`C
`(1)
`(1)
`
`> ro
`~
`
`0
`CX)
`LO
`
`0
`C")
`LO
`
`0
`.._,.
`CX)
`
`\
`"' l..,-/ ~
`--~
`--~ ~
`
`~
`
`E
`::>
`
`~ u CD a.
`
`CJ)
`
`C
`0
`CJ)
`-~
`E
`w
`
`-~
`
`-
`
`0
`0
`
`--
`
`0
`0)
`
`0
`CX)
`
`0
`f'-..
`
`0
`tO
`
`0
`LO
`
`.._,.
`0
`
`0
`C")
`
`0
`C\J
`
`>,
`
`e>
`........
`(1) ~
`C
`
`0 -w
`
`0
`CX)
`('I')
`
`0
`
`0
`
`--
`
`TCL 1037, Page 4
`LOWES 1037, Page 4
`VIZIO Ex. 1037 Page 0004
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 4 of 19
`
`5,998,925
`
`Fig.SA
`~.
`
`100
`
`I
`
`.
`
`11
`II
`
`' ' ' ,1 .....
`
`~
`
`Relative 50
`intensity
`
`(%)
`
`0
`200
`
`,...
`,
`
`I
`t
`
`'
`,.
`
`h
`
`, ...
`
`I
`
`'
`
`\
`
`J.
`
`\
`
`"
`
`~
`
`' " \
`
`•
`'
`,,
`\
`
`'
`. .....
`
`500
`Wavelength ( ). )
`
`I
`j
`, I/
`
`,~
`
`-- .J
`300
`
`....
`400
`Excitation spectrum
`
`Fig.SB
`100
`
`Relative
`intensity 50
`(%)
`
`•• I/
`./
`
`~ 0
`400
`
`J
`I
`
`J
`
`.. ,.
`
`I
`
`I
`
`'
`
`I'-
`
`II.
`,
`
`I
`I
`
`;J ,
`
`I
`
`'
`
`I
`
`J
`
`•
`Ir
`-,
`
`.,. -,
`600
`500
`Emission spectrum
`
`,
`
`~
`
`#
`
`.
`
`\
`
`I
`I
`
`"
`'
`
`'\
`
`1·.
`
`'
`
`I'.
`
`\
`
`!\
`'
`
`l'o,,
`
`,.
`
`-
`
`' ..
`
`'
`
`' ...
`-...
`---
`700
`Wavelength ( ). )
`
`TCL 1037, Page 5
`LOWES 1037, Page 5
`VIZIO Ex. 1037 Page 0005
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 5 of 19
`
`5,998,925
`
`Fig.6
`
`,_ _.... I I I +-+-+-1-+--+-+-+-1-+--+-+-+-+-+--+-+-+-+-+--f--+-+-+--+--f--+-+-+-+-+--+--+-1
`- - - 5 2 0 - - - - - - - - - - - - - - -
`-
`t=tj2-tttS-;;J:tt1=1Jttt1=1Jttt::t:::I:::Jttt1J=tt!=t=l=tt!=tJ=tt::tJ
`
`0.7 -H-l-+--f-t-+-t-+--f-t-+-t-+--f-t~--+--+--+--+-+-+--+--+--+-+--t-+--+--+--+-+-+-1--+-+-+-+--,f-i
`"'-
`
`N
`0.6 -1-t-l---l--+--+--l--l--l--l-+--l--......+--l-+--l--l--l-,>-1~',-31,.-1--1--1--4--l---l---+~-4---l---+~-4---l---+-+-le--l
`-++-+--+->---+---+---+--+--1-----+--+--+--+-1-----+---+-+--Hr D -l'\___,_---+--1>---+-+-+---+--11-----+-+---+---+--11-----+-+---+--+-f----i
`'/ I:', I'\
`- 500 ++++-+--l-HH-+-++++-+.E-f--Jlllil~'1n--+-+++++-H-+-H-+-++-H
`11,,.f""
`,-
`0 · 5 --l+f-++-+-+-f-++-+-+-J-++-f-+-h~~,,-1--f-+-¼-++,..~,. Ir+,..._ 580 -+-+--+-,f-+-+--+--+-+-+-l
`
`'
`
`y
`
`+-4--+-,~+--+-4-1--++-l---+-l-+.~'"-+--41-+--+-+-+-lf--VI .!14,r,-:-1.~"'1--+----'-+----l--------l>---+--l------+--+---'---+--1
`'~>-I +'----ll..._r+--1-+-+-+-+-1-+--f-t-+--1
`r r
`.II ,
`-
`
`0. 4 -+-it,++-+-f-+++-+-f-+_.-il ... 4-1-+t-++-i-+..i.,.~4--t-+-J-++-f-+-1 ' " " ' . . . +- 600 t-+-+-+-+-l
`\
`1
`
`-
`
`0. 3 ~,.... +-~ _-&4,_::8~-l---l,j:11111-"'~1-+-+--+--+-1-+--1.1;11'1---l--+--l---+-+-i.-!---1---+-+-11-+--+-+-+-11--"'"" ... + 62 0
`r
`\ -..;__, .,,,
`~"
`-+--+-H1 l-----t-''l.l'--t-+-1-++--t-+-+-+--j .. ~f-++--t-+-f-++-+-+-f-++-+-+-b,,t'!::+-t-+-t++--t
`,I
`0.2 -+-1-+--fl\r+--,f-lt--++-+-11-+-+--+~.__ .. 1-++-+-+-f-++-+-+-f-++~-1,,,,1F-~J-++-f-+-J-++-f-+-t
`- - 480
`,
`r
`l
`,
`I
`Q. 1 -+-J-+-1--f-+\ M,H-+-+-,j..i ~+-+-+-1-++..,.7""'1:...+-t-++-i-+t-++-i-+++-+-1-+++-+-H
`__ I I
`r'~--vf-++-+--bl"9-'+-+-+-1-++-+-+-J-++-f-+-J-++-i-+t-++-i-++-i
`-460, A (cid:127) ~ ~~ ,~
`,._ y}f"ll,-li"b,,l"'::+-t-+-1-++-+-+-1-++-f-+-¼-++-f-+-r++--t-++-++-i-++-i
`I
`I
`I
`I
`I
`I
`I
`I
`> 0.2
`0.1
`420
`
`'
`
`\
`1
`
`I
`
`I
`
`,I
`
`i,,
`
`-
`
`I
`
`0.3
`
`0.4
`
`0.5
`
`0.6
`
`0.7
`
`X
`
`TCL 1037, Page 6
`LOWES 1037, Page 6
`VIZIO Ex. 1037 Page 0006
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 6 of 19
`
`5,998,925
`
`Fig.7
`
`705
`
`Fig.8
`
`706
`
`707
`
`705
`
`705
`
`704
`
`Fig.9
`
`706
`
`707
`
`705
`
`TCL 1037, Page 7
`LOWES 1037, Page 7
`VIZIO Ex. 1037 Page 0007
`
`

`

`U.S. Patent
`
`Dec.7,1999
`
`Sheet 7 of 19
`
`5,998,925
`
`Fig.10
`
`601
`
`610
`
`, _____ ) ·------
`
`LED display unit
`
`-- - - --- - - - . - - -- -- -----,
`Driver
`602
`
`I
`I
`I
`I
`I
`I
`I
`
`Image data memory
`(RAM)
`
`Gradation control unit
`(CPU)
`
`603
`604
`L--------------------------------------------------------'
`
`TCL 1037, Page 8
`LOWES 1037, Page 8
`VIZIO Ex. 1037 Page 0008
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 8 of 19
`
`5,998,925
`
`Fig. 11
`
`505
`
`00000
`000000
`000000
`000000
`000000
`000000
`
`501
`
`506
`
`504
`
`Fig.12
`
`400
`
`401
`
`403
`
`404
`
`TCL 1037, Page 9
`LOWES 1037, Page 9
`VIZIO Ex. 1037 Page 0009
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 9 of 19
`
`5,998,925
`
`Fig.13A
`
`Life test
`lf=20mA Ta=25 °C
`
`120
`100 1--c-::-===-::::::--------
`80
`60
`
`1
`
`- -
`
`---~ ------,,
`
`...........
`
`Relative
`power
`(%)
`
`40
`
`20
`
`00
`
`200
`
`400
`
`600
`
`800
`
`1000
`
`Lighting time (H)
`
`Fig.138
`
`Life test
`lf=20mA Ta=60°C 90%RH
`
`Relative
`power
`{%)
`
`120
`
`100
`
`80
`
`60
`
`40
`
`20
`
`00
`
`\
`\
`\
`\
`\
`\
`\
`\
`\
`
`200
`
`400
`600
`Lighting time (H)
`
`800
`
`1000
`
`TCL 1037, Page 10
`LOWES 1037, Page 10
`VIZIO Ex. 1037 Page 0010
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 10 of 19
`
`5,998,925
`
`Fig.14A
`
`Weathering test
`100 ~ - - - - - - - - - -
`
`80
`
`Brightness
`holding rate 60
`(%)
`
`40
`
`20
`
`0
`
`Fig.148
`
`0.38
`
`0.34
`
`0.30
`
`0.26
`
`y
`
`', .... _ -------- .-.. ----- -.. ------
`
`200
`
`400
`
`600
`
`Time (hr)
`
`Ohr
`
`/
`
`480hr
`
`480hr
`0 .22 .___ _ _ _ __.__ _ _ _ ____. ______ _
`
`0.24
`
`0.28
`
`0.32
`
`0.36
`
`X
`
`TCL 1037, Page 11
`LOWES 1037, Page 11
`VIZIO Ex. 1037 Page 0011
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 11 of 19
`
`5,998,925
`
`Fig.15A
`
`Reliability test
`
`120
`
`80
`
`.... __
`100 r-::------------
`........... ________ ___
`----------...,. ---------
`
`Brightness
`holding rate 60
`(%)
`
`40
`
`20
`
`0
`
`Fig.158
`
`0.38
`
`0.34
`
`0.30
`
`y
`
`500
`
`Time (hr)
`
`1000
`
`I
`1000hr
`
`Ohr
`
`Ohr
`
`,
`,'
`,
`,,,/
`/ ,
`1000hr
`
`0.26 L - . _ _ _ _ _ . _ _ _ _ _ _ . _ _ _ _ _ _ _ ,
`
`0.24
`
`0.28
`
`0.32
`
`0.36
`
`X
`
`TCL 1037, Page 12
`LOWES 1037, Page 12
`VIZIO Ex. 1037 Page 0012
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 12 of 19
`
`5,998,925
`
`co
`,._
`" 0)
`......
`LL
`
`{0
`0
`
`~
`0
`
`X
`
`C\J
`0
`
`0
`
`(X)
`0
`
`{0
`0
`
`C\J
`0
`
`TCL 1037, Page 13
`LOWES 1037, Page 13
`VIZIO Ex. 1037 Page 0013
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 13 of' 19
`
`5,998,925
`
`-C:
`Q) -C
`0
`0 ";R
`..... 0
`Q) 0
`..c r--.
`... ,ro
`a.
`..
`(/)
`.c a..
`,._
`'
`...
`._
`'
`
`I'-....
`,._
`0)
`-..._
`LL..
`
`• JJ
`
`'
`'
`
`'
`
`-
`-C
`
`C:
`Q)
`
`0
`0 ";R
`..... 0
`Q) 0
`.c (0
`C.
`(/)
`0
`..c
`a..
`
`-
`-
`
`C
`Q)
`C
`0
`0 ";R
`i,.._O
`Q) 0
`..c (")
`a.
`(/)
`0
`..c
`a..
`
`'
`
`'
`
`0
`..c
`a..
`'
`' '
`'
`'
`'
`' '
`'
`'
`'
`'
`'
`' '
`'
`'
`' '
`
`Cl
`w
`__.J
`I
`Q)
`:J
`co
`
`C
`Q)
`
`0
`0 ";R
`..... 0
`Q) 0
`.c (")
`
`'
`'
`'
`
`-
`-C
`- a.
`' , r(/)
`
`l{)
`0
`
`V
`0
`
`X
`
`(")
`ci
`
`C\I
`0
`
`'T"°"
`
`00
`0
`
`(0
`0
`
`LO
`0
`
`V
`0
`
`(")
`0
`
`C\I
`0
`
`'T"°"
`
`ci
`
`TCL 1037, Page 14
`LOWES 1037, Page 14
`VIZIO Ex. 1037 Page 0014
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 14 of' 19
`
`5,998,925
`
`<ll 60
`
`Fig.18A
`100
`JJ 90
`<ll 80
`e <" 70
`a 5o
`(1)
`~ 40
`~ 30
`'Zc, 20
`~ 10
`0
`380
`Fig. 188
`100
`::o 90
`ro 80
`e 7
`<" 0
`(1) 60
`a 50
`(1)
`~ 40
`~ 30
`£ 20
`10
`-
`0
`380
`Fig.18C
`100
`JJ 90
`<ll 80
`~ 70
`ro 60
`3. 50
`(D
`~ 40
`~ 30
`-zo 20
`~ 10
`0
`380
`
`I ~
`I
`\.
`\
`I
`
`l
`
`I
`I
`I
`I
`I u ·
`
`\
`
`\
`
`\. ' "r-...
`
`"'- ----.
`
`430
`
`480
`
`580
`530
`(nm)
`Wavelength
`
`630
`
`680
`
`730
`
`"
`
`j
`
`I
`I
`I
`
`,)
`430
`
`j
`I
`I
`I
`
`/
`430
`
`\
`\
`480
`
`580
`530
`Wavelength (nm)
`
`r,
`
`630
`
`680
`
`730
`
`/
`
`...............
`
`"'r---....
`
`/
`
`_,,,, --
`\
`
`480
`
`580
`530
`(nm)
`Wavelength
`
`630
`
`............. - --
`
`680
`
`730
`
`TCL 1037, Page 15
`LOWES 1037, Page 15
`VIZIO Ex. 1037 Page 0015
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 15 of 19
`
`5,998,925
`
`/ "
`
`\
`
`\
`\
`\
`
`\. ·,
`' "
`
`I
`I
`I
`I
`I
`J
`I
`I
`L../
`480
`
`580
`530
`Wavelength
`(nm)
`
`630
`
`680
`
`730
`
`430
`
`n
`
`Fig.19A
`100
`:n 90
`~ 80
`~ <' 70
`co 60
`a 50
`(D
`~ 40
`~ 30
`
`'° 20
`
`~ 10
`0
`380
`Fig. 198
`100
`:o 90
`ro 80
`e <' 70
`ro 60
`a 5o
`(I)
`~ 40
`~ - 30
`
`~ 20
`-
`10
`0
`380
`Fig.19C
`100
`:o 90
`~ 80
`e <" 70
`ro 60
`a 50
`(l)
`~ 40
`~ - 30
`
`I
`
`I
`
`/
`430
`
`(,
`
`~ 20
`-- 10
`0
`380
`
`)
`
`/
`
`430
`
`\
`\
`
`'-
`480
`
`580
`530
`Wavelength
`(nm)
`
`630
`
`680
`
`730
`
`-
`
`.. v
`\
`'" ~
`-
`480
`580
`530
`Wavelength
`(nm)
`
`""""-... ........
`
`630
`
`-----
`
`680
`
`730
`
`TCL 1037, Page 16
`LOWES 1037, Page 16
`VIZIO Ex. 1037 Page 0016
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 16 of 19
`
`5,998,925
`
`Fig.20A
`100
`:o 90
`~ 80
`~ <" 70
`CD 60
`3. 50
`([)
`~ 40
`~ 30
`~ 20
`-- 10
`0
`3·80
`Fig.208
`100
`JJ 90
`~ 80
`9l <" 70
`ro 60
`a 50
`([)
`~ 40
`~ - 30
`
`430
`
`n
`
`I
`
`I
`I
`I
`I
`I
`I
`I
`I
`I
`
`__.,,,
`480
`
`""' \
`
`I\
`\
`\
`\
`
`' l\s
`
`'\. ' ........
`
`530
`Wavelength
`
`580
`(nm)
`
`630
`
`i--..
`680
`
`730
`
`\
`\
`'-
`480
`
`580
`530
`Wavelength (nm)
`
`630
`
`680
`
`730
`
`j
`
`I
`
`/
`430
`
`~ 20
`-- 10
`0
`380
`Fig.20C
`100
`:o 90
`ro 80
`~ <. 70
`ro 60
`a so
`{t)
`~ 40
`~ 30
`w 20
`3 10
`/
`.
`0
`380 . 430
`
`I
`
`j
`
`\
`\
`
`' V
`
`480
`
`/
`I
`
`.............
`
`"'-
`
`580
`530
`Wavelength (nm)
`
`............ ......
`
`630
`
`-----
`
`680
`
`730
`
`TCL 1037, Page 17
`LOWES 1037, Page 17
`VIZIO Ex. 1037 Page 0017
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 17 of 19
`
`5,998,925
`
`Fig.21A
`100
`JJ 90
`co 80
`a <" 70
`CD 60
`a 5o
`ct>
`fJ 40
`~ 30
`'° 20
`
`!:!) 10
`0
`380
`Fig.21 B
`100
`:n 90
`co 80
`Ill
`~ 70
`CD 60
`a 50
`(t)
`~ 40
`~-- 30
`~ 20
`--- 10
`0
`380
`Fig.21C
`100
`::o 90
`~ 80
`a <" 70
`co 60
`a so
`co
`~ 40
`~ 30
`~ 20
`._ 10
`0
`380
`
`/
`
`n
`
`' \
`\ ' \.
`
`480
`
`j
`J
`430
`
`( '
`
`\
`\
`
`/
`
`J
`
`430
`
`480
`
`----,
`
`' \
`
`\
`
`~
`
`I
`I
`I
`I
`
`I
`I
`I
`I
`
`\
`
`\. "' "I"-....
`
`480
`
`580
`530
`Wavelength
`(nm)
`
`630
`
`/
`430
`
`............ ---
`
`680
`
`730
`
`580
`530
`Wavelength (nm)
`
`630
`
`680
`
`730
`
`-----...... -- -----
`
`630
`
`580
`530
`Wavelength (nm)
`
`680
`
`730
`
`TCL 1037, Page 18
`LOWES 1037, Page 18
`VIZIO Ex. 1037 Page 0018
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 18 of 19
`
`5,998,925
`
`.... I'\.
`'\.
`\
`
`\
`
`~
`\
`
`/
`I
`
`J
`I
`I
`I
`I
`I
`I
`
`580
`530
`Wavelength (nm)
`
`630
`
`-V
`
`480
`
`430
`
`" " ~ ---
`
`680
`
`730
`
`/ "
`"
`
`'\.
`
`I
`I
`I
`
`i\.
`'\.
`'\.
`
`I
`I
`I
`I
`. /
`480
`
`580
`530
`Wavelength (nm)
`
`11
`
`'\ " '
`
`630
`
`680
`
`730
`
`Fig.22A
`100
`JJ 90
`~ 80
`e?. <" 70
`m 60
`a: 5o
`(1)
`~ 40
`~- 30
`
`'° 20
`e 10
`0
`380
`Fig.228
`100
`JJ 90
`CD 80
`Ill
`~- 70
`CD 60
`§: 50
`(1)
`~ 40
`~ 30
`w 20
`~ 10
`0
`380
`Fig.22C
`100
`JJ 90
`CD 80
`
`a <' 70
`CD 60
`a. 50
`co
`~ 40
`~ 30
`w 20
`~ 10
`0
`380
`
`430
`
`j
`
`I
`I
`I
`V
`430
`
`l
`
`\
`\
`\.
`
`480
`
`580
`530
`Wavelength (nm)
`
`630
`
`680
`
`730
`
`TCL 1037, Page 19
`LOWES 1037, Page 19
`VIZIO Ex. 1037 Page 0019
`
`

`

`U.S. Patent
`
`Dec. 7, 1999
`
`Sheet 19 of 19
`
`5,998,925
`
`0
`. . . . . - - - - - - - - - - - - - - - - - - - - - - - . LO
`r---
`
`-E
`C -..c.
`
`+-'
`0)
`C
`(1)
`(1)
`
`> en
`3:
`
`0
`0 r---
`
`0
`LO
`<O
`
`0
`0 co
`
`0
`LO
`LO
`
`0
`0
`LO
`
`0
`LO
`~
`
`0
`0
`~
`
`C'f")
`C\J
`•
`0)
`
`·--LL
`
`.___ _
`
`_
`
`_
`
`0
`0
`
`0
`a)
`
`0
`....__ _ _ _ __.__ _ _ _ __.__ _ _ _ __._ _ _ _ _ . LO
`(I')
`0 co
`
`0
`C\J
`
`0
`
`Relative intensity (%)
`
`TCL 1037, Page 20
`LOWES 1037, Page 20
`VIZIO Ex. 1037 Page 0020
`
`

`

`5,998,925
`
`1
`UGHT EMITTING DEVICE HAVING A
`NITRIDE COMPOUND SEMICONDUCTOR
`AND A PHOSPHOR CON'D\INING A
`GARNET l•LUORESCE T MATERIAL
`
`BACKGROUND OF THE JNVENTION
`
`1. (Field of tbe Invention)
`The preseDl invention relates lo a light emitting diode
`used in LED display, back light source, traffic signal, trail(cid:173)
`way signal, illuminating switch, indicator, etc. More
`particularly, it relates to a light emitting device ( ED)
`compri ing a phosphor, which converts the wavelength of
`light emitted by a light emitting component and emits ligbt,
`and a display device using the light emilling device.
`2. (Description of Related Art)
`A ligh t emitting diode i compact and emits light of clear
`color with bigb efficiency. It i. also free from such a trouble
`a bum-ou t and has good initial drive characteristic, high
`vibration resistance and durability 10 endure repetitive
`ON/OFF operations, because it is a semiconductor element.
`Thus it has been used widely in uch application as variou
`indicators and various light sources. Recently light emiltiag
`diodes for RGB (red, green and blue) colors having ultra(cid:173)
`high luminance and high efficiency have bee(cid:143) developed,
`and large screen LED displays using these light emitting
`diodes have been put into use. The LED display can be
`operated with less power and ba
`ucb good characteristics
`as light weight and long life, and is therefore expected to be
`more widely used in the future.
`Recently, various auempts have been made to make white
`light sou.recs by using light emitting diode . Because the
`light emitting diode has a favorable emission spectrum to
`generate monochromatic light, making a light source for
`white light requires it to arrange lb.rec light emilling com(cid:173)
`ponents of R, G and B closely to each other while diffusing
`and mixing the Light emitted by them. When generating
`white light with such an arrangement, there has bee(cid:143) such a
`problem that white light of the desired tone cannot be
`generated due to variations in lbe tone, luminance and other
`factors of the light emitting compooeat. AJso when the light
`emitting components are made of difl'erent materials, elec(cid:173)
`tric power required for driving differ from one light emit(cid:173)
`ting diode to another, making it necessary to apply different
`voltages differe(cid:143) I light emitting components, which leads lo
`complex drive circuit. Moreover, because the light emitting
`components are semiconductor light emitting components,
`color tone is subject to variation due to the difference in
`temperature characteristics, chronological changes and oper(cid:173)
`ating environment, or uaevccmess in color may be caused 50
`due to failu.re in uniformly mixing lbe light emilled by the
`Light emitting components. Thus light emitting diodes are
`effective as light emiui(cid:143) g devices for generating individual
`colors, although a satisfactory light source capable of emit(cid:173)
`ting white light by using light emitting compo(cid:143) e(cid:143)
`ts bas 001 55
`been obtained so far.
`In order to olve tbese problems, the present applicant
`previously developed light emitting diodes which convert
`the color of light, which is emiued by light emitting
`compoaeals, by means of a fluorescent material disclosed in 60
`Japanese Patent Kokai Nos. 5-152609, 7-99345, 7- 176794
`and 8-8614. Tbe light erniuing diodes di closed in these
`publications are such that, by using light emitting compo(cid:173)
`nents of one kind, are capable of generating light of while
`and other colors, and are constituted as follows.
`The light emilling diode disclosed ia the above gazettes
`are made by mounting a light emilling component, having a
`
`5
`
`15
`
`2
`large energy band gap of light emuung layer, in a cup
`provided al the tip of a lead frame, and having a fluoresceDl
`material that absorbs light emjtled by the light emitting
`component and emits light of a wavelength different from
`that o[ the absorbed light (wavelength conversion), con(cid:173)
`tained in a re in mold which covers the light emilling
`component.
`The light emilling diode disclosed as described above
`capable of cmilling white light by mixing the light of a
`JO plurality of ources can be made by using a light emitting
`component capable of emilling blue light and molding the
`light emitting component with a resin including a fluorescent
`material that absorbs the light emiued by the blue light
`emitting diode and emits yellowish light.
`However, conventional light emilling diodes have such
`problem a. deterioration of the fluorescent material leading
`to color tone deviation and darkening of the fluorescent
`material resulting in lowered efficiency of extracting light.
`Darkening here refers to, in the case of using an inorganic
`20 fluorescent material uch as ( d, Zn)S fluorescent material ,
`for example, part of metal element con tiluting the fluo(cid:173)
`rescent material precipitate or change their properties lead(cid:173)
`ing to coloration, or, in the case of using an organic
`fluorescent material, coloration due to breakage of double
`25 bond in the molecule. Especially when a light emitting
`componen t made of a emiconductor having a high energy
`band gap is used to improve the conversion efficiency of the
`fluorescent material (that is, energy of light emitted by the
`emiconduclor i increased and number of photons having
`30 energies above a threshold which can be absorbed by the
`f:luore cent material increases, resulting in more light being
`absorbed), or the quantity of fluorescent material consump(cid:173)
`tion is decreased (that is, tbe fluorescent material is irradi(cid:173)
`ated with relarively higher energy), light energy absorbed by
`35 tbe fluorescent material inevitably increases resuiting in
`more significa(cid:143) 1 degradation of the fluorescent material. Use
`of the light cmilling component with higher intensity of light
`emission for a(cid:143) extended period of time causes further more
`significant degradation of the fluorescent materia l.
`AJso the fluorescent material provided in the vicinity of
`tbe Iigbt emitting component may be exposed to a high
`temperature such as rising temperature of the light emitting
`component and beat transmitted from the external environ-
`45 meat (for example, sunlight in ca e the device is used
`outdoors).
`Further, some fluorescent materials are subject to accel(cid:173)
`erated deterioration due to combination of moisture entered
`from the outside or introduced during the production
`proce
`, tbe light and beat traa. milled from the light emit(cid:173)
`ting component.
`When it comes to an organic dye of ionic property, direct
`current electric field in the vicinity of the chip may cause
`electrophoresis, resulting in a change in the color tone.
`
`40
`
`SUMMARY OP THE INVENTION
`Thus, aa object of the present invention is to solve the
`problems described above and provide a light emitting
`device which experiences only extremely low degrees of
`deterioration in emission light intensity, light emission effi(cid:173)
`ciency and color hift over a long time or use with high
`luminance.
`Tbe present applicant completed the preseDl invention
`through researches based oa the assumption that a light
`65 emiuiag device having a light emilling component and a
`fluorescent material must meet the follovring requirement
`to achieve the above-mentioned object.
`
`TCL 1037, Page 21
`LOWES 1037, Page 21
`VIZIO Ex. 1037 Page 0021
`
`

`

`5,998,925
`
`3
`(1) The light em1llrng compo(cid:143) e(cid:143)
`l mu ·1 be apable of
`emilling light of high luminance with light emiuing char(cid:173)
`acteristic which is stable over a long time of use.
`(2) The fluorescent material being provided in the vicinity
`o( the high-luminance light emitting component, must . how 5
`exce llent resistance against light and heat so that the prop(cid:173)
`erties thereof do not change even when used over an
`extended period of time while being exposed to light of high
`intensity emitted by the light emilling component
`(particularly the fluorescent material provided in ihe vicinity JO
`o[ the light emilling component is exposed to light of a
`radiation intensity as high as about 30 to 40 times that of
`sunlight according 10 our estimate, and is required to have
`more durability against light as light emitting component of
`higher luminance i used).
`(3) With regard to the relation hip with lhe light erailliag
`component, the fluorescent material must be capable of
`absorbing with high efficiency the light of high mo(cid:143) ocbro(cid:173)
`maticity emitted by the light emitting component and emit(cid:173)
`ting light of a wavelength different from that of the light 20
`emitted by lhe light emitting component.
`Thu
`the present invention provide a light emilling
`device, comprising a light emitting component and a phos(cid:173)
`phor capable of absorbing a pan of light emilled by the light
`emiuing component and emitting light of wavelength dif(cid:173)
`ferent from that of the ab orbed light; wherein aid light
`emitting cocnponenl comprises a nitride compound secni(cid:173)
`co(cid:143) ductor represented by the formula: l n;GaiAl'-N where
`0~i, 0~j, 0~k and i+j+k=l) and said phosphor contains a 30
`garnet liuorescent material comprising 1) al least one ele(cid:173)
`ment elected from the group con isling ofY, Lu, Sc, La, Gd
`and Sm, and 2) at least one element selected from the group
`consisting of Al, Ga and l(cid:143), and being activated with cerium.
`The nitride compound semiconductor (generally repre- 35
`senled by chemical fornm la lo;GaiAli,N where 0~i, 0~j,
`0 ~ k and i+j+k=l) mentioned above contain variou mate(cid:173)
`rials including I(cid:143) GaN and GaN doped with various impu-
`rities.
`The phosphor mentioned above contains various materi(cid:173)
`als defined a described above, including Y 3AI 50 12:Ce and
`Gd3In50J2: e.
`Because the light emitting device of the present invention
`uses the light emitting component made of a nitride com(cid:173)
`pound semiconductor capable of emitting light with high
`luminance, the light emitting device is capable of emilling
`light witb higb luminance. Also tbe phosphor used in the
`light emitting device has excellent resistance again I light o
`that the fluorescent properties thereof experience less change
`even when used over an extended period of time while being so
`exposed 10 light of high intensity. This makes it po
`ible to
`reduce the degradation of characteristics during long period
`of u e and reduce deterioration due to light o( high inten ity
`emitted by the light ecnitting component as well as extra(cid:173)
`neous light (sunlight including ultraviolet light, etc.) during
`outdoor use, thereby to provide a light emi11ing device which
`experiences extremely less color sbifl and le~ luminance
`decrease. The light emittfog device of the present invention
`ca(cid:143) also be used i(cid:143) such applications that require response
`speeds as high as 120 nsec., for example, because tbe
`phosphor used therein allows after glow only for a hon
`period of time.
`The phosphor used i(cid:143)
`the light emiuing diode of the
`present invention preferably contains an yllrium-alumiaum(cid:173)
`garnel fluorescent material that contains Y and Al, which
`enable · it 10 increase the luminance of the light emitting
`device.
`
`4
`In the light emitting device of the present invention, the
`phosphor may be a fluorescent material represented by a
`general formula (Re1 _,Sm,)iAl1_sGa,)5 0 12:Ce, where
`0~r<l a(cid:143) d 0~s ~ J and Re is at least one elected from Y
`and Gd, in which case good characteristics can be obtained
`similarly 10 the case where the yttrium-aluminum-garnet
`fluorescent material is used.
`Also in the light emitting device of the present invention,
`it i preferable, for the purpo ·e of reducing the temperature
`dependence of light emission characteristics (wavelength of
`emitted light, intensity of light emission, etc.), to use a
`fluorescent material repre ·ented by a general formula
`(Y 1 _p_q_,GdP e'i( m,h(Al J_, Ga,) 50 12 as the phosphor,
`where 0~p~0.IS, 0.003~q~0.2, 0.0003~r~0.08 and
`0 ~s~l.
`Also in the light emilling device of the prese(cid:143) I invention,
`the pho phor may contain two or more yttrium-aluminum(cid:173)
`garnet fluorescent materials, activated with cerium, of dif(cid:173)
`ferent compositions including Y and Al . Witb this
`co(cid:143) .figu ration, light of desired color can be emitted by
`controlling the emission spectrum of the phosphor according
`to the property (wavelength of erailled light) of the light
`emitting component.
`Further in tbe light emi11ing device of the present
`invention, in order to have light of a . pecified wavelength
`25 emitted by the light emilli ng device, it is preferable that the
`phosphor contains two or more fluorescent materials of
`different compositions represented by general formula
`(ReJ_,Sm,)iA1 1_,Ga, )50 12:Ce, where 0~r<l and 0~s~l
`and Re i. al least one selected from Y aad Gd.
`Also in the light emilling device of the presc(cid:143) 1 invention,
`in order to control the wavelength of emilled light, the
`pho · phor may ontain a first fluorescent material repre(cid:173)
`sented by general formula Y iA1 1_,Gas)sO 12: e and a sec(cid:173)
`ond fluorescent material represented by general formula
`Re 3Al50 12:Ce, wbere 0~s~ 1 and Re is at least one selected
`from Y, Ga and l a.
`Also in the light emilling device of the present invention,
`i(cid:143) order to control the wavelength o[ emitted light, the
`phosphor may be an yllriucn-a lu.minum-garnet fluorescent
`40 material containing a first fluorescent material and a second
`fluorescent material, with di.lierenl parts of each yttrium
`being substituted with gadolinium .
`the light emitting device of the pre eat
`Further in
`invention, it is preferable that main emission peak of the
`45 light emilling component is set within the range from 400
`nm lo 530 nm and main ecnissio(cid:143) wavelength of the phos(cid:173)
`phor is et to be longer than the main emission peak of the
`it possible to effi-
`light emitting component. This make
`ciently emit white light.
`Further i(cid:143)
`the light emitting device of the prese(cid:143) I
`invention, it is preferable that the light ecnitting layer of the
`light emilling component contains gallium nitride emicon(cid:173)
`ductor which contain
`In, and the pho phor is yttrium(cid:173)
`alu mi(cid:143) u m-gar(cid:143) et fluorescent material wherein part of Al is
`55 substituted by Ga so that the proportion of Ga:Al is within
`the range from 1: 1 to 4:6 and part of Y is ubstiluted by Gd
`o that the proportion of Y:Gd is wi thin the range from 4:1
`to 2:3. Absorption pectrum of the pho phor which is
`controlled as described above shows good agreement with
`that of light emilled by the light emilling component which
`contain gallium nitride semiconductor including la as the
`light emitt ing layer, and is capable of improving the con(cid:173)
`version efficiency (light emission efficiency). Also the light,
`generated by mixing blue light emitted by the light ecnilting
`65 component and fluorescent light of the fluorescent material,
`is a white light of good color rendering and, in this regard,
`an excellent light emitting device can be provided.
`
`15
`
`60
`
`TCL 1037, Page 22
`LOWES 1037, Page 22
`VIZIO Ex. 1037 Page 0022
`
`

`

`5,998,925
`
`20
`
`6
`compositions represented by a gene ral formu la (Re l _,.Sm,h
`(Al l- s Ga.)5 Ol 2 :Cc, where 0~r<l and 0~s~l and Re is at
`least one selected from Y and Gd may be used as the
`phosphor in order to control the emitlcd ligbt to a desired
`5 wavelength.
`In the light emitting diode of the present inve ntion,
`similarly, a first lluorcsccot material represented by a genera l
`formula YiAl1_, Ga,)5OJ2:Ce and a secoad fluorescent
`material reprcseoted by a general formula Re3Al 5O12:Ce,
`JO may be used as the phosphor where 0~s~ land Re is at least
`one selec ted from Y, Ga and La, in order to co ntrol the
`emilled ligbt to a desired wavelength.
`la tbe ligbt emit ting diode of the present invention,
`similarly, yurium -aluminum-garoet l:luorcsceot material a
`first fluorescent material and a second fluorescent material
`may be used wherein part of yttrium being sub tituled with
`gadolinium lo different degrees of substitution as the
`phosphor, in order to control the emitted light to a desired
`wavelength.
`Generally, a fluorescent material which absorbs light of a
`short wavelength and e mits light of a long wavelength has
`higber efficiency th an a fluorescent material which absorb
`light of a long wavelength and emits light of a short
`wavelength. It is preferable 10 use a light emining compo(cid:173)
`nen t w hich emits visible light than a lig ht emill'i ng compo(cid:173)
`nent wbich emit ultraviolet light tbat degrade
`re in
`(molding material, coaling material, elc.). Tbus for the light
`emilli(cid:143) g diode of the present invention, for the purpose of
`
`30 ~~r;~te~a!1: ~;a~1 ;~i~l~~i \~oc~e::I aont,i~~~;~/~~11~~~
`
`component be set within a relatively hort wavelength range
`of 400 om to 530 nm in the visible light region, and main
`emission wavelength of the phospbor be set to be longer tba(cid:143)
`the main emissio n peak of the light emi lling component.
`With th is arrangement, because light converted by the
`fluoresceat material has longer wavelength than that of light
`emilled by the light cmilling component, ii will not be
`absorbed by tbe light emilling component even when the
`40 light emitting component i irradiated with light which ha
`been reflected and converted by the fluorescent material
`( ince the energy o[ the converted light i less lhaa the band
`gap energy). Thus the ligbl which has been reflected by the
`fluorescent material or the like is reflected by the cup
`45 wberein the