`
`43
`
`US007531960B2
`
`a2) United States Patent
`Shimizu et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,531,960 B2
`May12, 2009
`
`(54) LIGHT EMITTING DEVICE WITH BLUE
`LIGHT LED AND PHOSPHOR COMPONENTS
`
`(75)
`
`Inventors: Yoshinori Shimizu, Tokushima(JP);
`Kensho Sakano, Anan (JP); Yasunobu
`Noguchi, ‘Tokushima (JP); Toshio
`Moriguchi, Anan(JP)
`
`(73) Assignee: Nichia Corporation, Anan-shi (JP)
`
`(*) Notice:
`
`Subject to anydisclaimer, the termof this
`patent
`is extended or adjusted under 35
`U.S.C. 154(b) by 233 days.
`
`(21) Appl. No.: 11/682,014
`
`Filed:
`Eile
`
`22)
`2):
`(65)
`
`Mar. 5, 2007
`an
`Prior Publication Data
`
`Jul. 12, 2007
`US 2007/0159060 Al
`oo
`;
`Related U.S. Application Data
`
`(58) Field of Classification Search......... 313/498-3512;
`428/690; 257/103
`See applicationfile for complete search history.
`References Cited
`U.S. PATENT DOCUMENTS
`
`(56)
`
`3.510.732 A
`
`5/1970 Amans
`
`(Continued)
`FOREIGN PATENT DOCUMENTS
`
`DE
`
`3804293 Al
`
`8/1989
`
`ai
`ts
`(Continued)
`OTHER PUBLICATIONS
`
`Branko et al., Development and applications of highbright white
`LEDlamps, Nov. 29, 1996, The 264th Proceedingsofthe Institute of
`PhosphorSociety, pp. 4-16 ofthe English translation.
`
`(62) Divisionofapplication No. 10/609,402, filed onJul. 1,
`(Continued)
`;
`2003, now Pat. No. 7,362,048, which ts a division of
`Primary Examiner—Joseph L Williams
`application No. 09/458,024,filed on Dec. 10, 1999,
`(74) Attorney, Agent, or Firm—Birch, Stewart, Kolasch &
`nowPat. No. 6,614,179, whichis adivision ofappli-
`Birch, LLP
`cation No. 09/300,315,filed on Apr. 28, 1999, nowPat,
`No. 6,069,440, whichis a division ofapplication No.
`08/902,725,filed onJul. 29, 1997, nowPat. No. 5,998, ©)
`925,
`
`neste)
`
`G9)
`
`sit
`
`Korelgn Application Priority Date
`
`‘
`
`5st
`
`Jul. 29, 1996
`Sep.1751996
`Sep. 18.1996
`Dec. 27,1996
`Mar. 31,1997
`
`seakiacsasi POB-198585
`(SP)
`GB) cscs P 08-244339
`(IP)
`eeseesssesssseeesneeessseeeee P 08-245381
`.. PO8-359004
`(JP)
`
`(JP)
`.. P09-081010
`
`(51)
`
`Int. Cl.
`(2006.01)
`HOSB 33/00
`(52) US. Ch cee 313/512; 257/103; 428/690
`
`200
`
`A light emitting device includes a light emitting component;
`
`anda slashereanable afabaorbinws part oflight smitet by
`
`the light emitting component and emitting light of a wave-
`length different fromthat ofthe absorbed light. A straightline
`connecting a point ofchromaticity correspondingto a peak of
`the spectrumgenerated bythe light emitting component and
`a point of chromaticity corresponding to a peak ofthe spec-
`trum generated by the phosphoris disposed along with the
`black body radiation locus in the chromaticity diagram.
`
`23 Claims, 19 Drawing Sheets
`
`203
`
`202
`
`201
`
`204
`
`205
`
`teDsSN VY,
`RXsy LZ
`
`SSSSSZRESSSSSSSS
`
`
`
`
`
`TCL 1036, Page 1
`LOWES 1036, Page 1
`
`LOWES 1036, Page 1
`
`

`

`US 7,531,960 B2
`
`Page 2
`
`
`
`
`
`7/1989
`OL-189695 A
`JP
`U.S. PATENT DOCUMENTS
`7/1989
`OLI79471L A
`JP
`.
`10/1989
`01-257993 A
`Jp
`3/1972 Pinnowet al.
`3,652,956 A
`10/1989
`01-260707 A
`IP
`9/1972 Pinnowetal.
`3,691,482 A
`4/1990
`02-111922 A
`JP
`10/1972 Pinnowet al.
`3,699,478 A
`3/1991
`324692
`JP
`6/1974 Stevensonetal.
`3,819,974 A
`6/1991
`03-152898 A
`IP
`4/1975 Kano et al,
`3,875,456 A
`3/1992
`4-80286 A
`IP
`11/1981 Bongerset al.
`4,298,820 A
`5/1992
`463162
`Ip
`2/1982 Barnes
`4314,910 A
`§/1992
`463163
`J
`10/1985 Berkstesseretal.
`4,550,256 A
`8/1992
`4-234481 A
`IP
`2/1987 de Hair et al.
`4,644,223 A
`3/1993
`5-226676
`IP
`12/1987 Huiskes etal.
`4.716337 A
`6/1993
`05-142424 A
`IP
`2/1988 van Kemenadeetal.
`4,727,283 A
`6/1993
`5152609 A
`JP
`2/1990 Chinoneet al.
`4,905,060 A
`6/1993
`05152609 A
`Ip
`4/1991 Matsuoka et al.
`5,006,908 A
`7/1993
`5183189 A
`IP
`6/1992 Patton etal.
`5.118.985 A
`8/1993
`05-63068 LU
`IP
`4/1993 Sluzky et al.
`5,202,777 A
`8/1993
`563068
`Ip
`10/1993 Van Pet eghem
`5,257,049 A
`2/1994
`06-027327 A
`JP
`11/1994 Tamaki etal.
`5,369,289 A
`3/1994
`06-82633 A
`JP
`11/1995 De Backeret al.
`SATLIIS A
`4/1994
`6-L15158
`IP
`8/1996 Tanaka et al.
`5,550,657 A
`5/1994
`06-139973 A
`JP
`11/1996 Nakamura etal.
`5,578,839 A
`6/1994
`04599224 Al
`JP
`2/1997 Imai et al.
`5,602,418 A
`6/1994
`06-160635 A
`IP
`12/1997 Yamazaki etal.
`§,700,713 A
`6/1994
`06-177423 A
`IP
`8/1998 Nitta
`5,798,537 A
`6/1994
`06177423
`IP
`10/1998 Ligthart et al.
`5,825,125 A
`7/1994
`6208845
`Jp
`12/1998 Butterworth et al.
`5,847,507 A
`8/1994
`06-231605 A
`JP
`9/1999 Lowery
`5,959,316 A
`9/1994
`06260680
`JP
`12/1999 Noll
`6,004,001 A
`9/1994
`06268257
`IP
`§/2000 Hohnet al.
`6,066,861 A
`4/1995
`7.99345 A
`JP
`3/2003 Duggal etal.
`6,538,371 Bl
`§/1995
`07-114904 A
`JP
`6/2003 Reeh etal.
`6,576,930 B2
`5/1995
`07-120754 A
`Jp
`8/2004 Kunihara et al.
`6,784,511 Bl
`6/1995
`7-32638 U
`JP
`11/2004 Reeh etal.
`6,812,500 B2
`7/1995
`7-42152 U
`JP
`10/2001 Reeh etal.
`2001/0030326 Al
`7/1995
`742152
`JP
`a
`separ
`‘
`*
`7/1995
`07176794 A
`IP
`FOREIGN PATENT DOCUMENTS
`9/1995
`07-235207 A
`JP
`9013615 U
`1/1991
`DE
`BURDDS
`Piesel
`uF
`0209942 Al
`1/1987
`EP
`12/1995
`7-321407
`JP
`0383215 A
`8/1990
`EP
`GHG Ee
`af
`0500937 Al
`9/1992
`EP
`
`
`
`EP SEE),=Eee0541373 A2 11/1992 a
`
`EP
`0.667383 A2
`8/1995
`r
`ale
`thee
`Gs
`esi
`Li
`eee,
`GB
`2000 173 A
`1/1979
`.
`=
`:
`:
`GB
`1589964
`5/1981
`JP
`09027642 A
`1/1997
`IP
`4717684
`9/1972
`JP
`10036835 A
`2/1998
`Jp
`49 106283
`12/1972
`JP
`11-500584
`1/1999
`Pp
`5079379
`11/1973
`Ip
`2000-5 12806
`9/2000
`JP
`491221
`1/1974
`JP
`2001-320094 A
`11/2001
`JP
`49112577
`10/1974
`JP
`2002-270020 A
`9/2002
`JP
`49-122292
`LL/1974
`wo
`97/350132 Al
`12/1997
`JP
`5043913 Cl
`4/1975
`wo
`98/12757 Al
`3/1998
`JP
`5245181
`LO/1977
`JP
`53-7153
`1/1978
`.P
`5331584
`3/1978
`JP
`5472484
`11/1978
`JP
`5441660
`12/1979
`JP
`55-4898 A
`1/1980
`JP
`35-005533 A
`1/1980
`JP
`554898 A
`1/1980
`JP
`59-30107 U
`2/1984
`JP
`5950445
`4/1984
`JP
`60144381
`7/1985
`JP
`60-185457 A
`9/1985
`JP
`62189770
`2/1986
`JP
`61-158606
`7/1986
`JP
`62-20237 A
`L/ 1987
`JP
`62167387
`T/A987
`JP
`621673987
`7/1987
`JP
`62-232827 A
`10/1987
`JP
`291980
`9/1988
`
`A
`‘ln
`OTHER PUBLICATIONS
`Nikkei Sangyo Shin-bun of Sep. 13, 1996.
`S. Nakauraet al., Japanese Journal ofApplied Physics Part 2, vol. 31,
`No. LOB, 1992, pp. L.1457-L.1459,
`Mitsubishi Electric Company Technical Report, vol. 48, No. 9, 1974,
`pp. 1121-1124.
`Proceedings of Illumination National Convention in 1983, p. 12.
`Phosphor Handbook, Ist Edition, 1987, pp. 233-240 and 275-277.
`Journalofthe Television Society, vol. 47, No. 5, 1993, pp. 753-764.
`R. W. G. Hunt, Color Research & Application,vol. 16, No. 3. 1991,
`pp. 146-165.
`Y. Nayatani, Color Research & Application, vol. 20, No. 3, Jun. 1995,
`pp. 143-155.
`M. Ikeda et al., Color Research & Application, vol. 14, No. 4, Aug.
`1989, pp. 198-206.
`M. Ikeda et al., Color Research & Application, vol. 16, No. 2, Apr.
`1991, pp. 72-80.
`
`TCL 1036, Page 2
`LOWES 1036, Page 2
`
`LOWES 1036, Page 2
`
`

`

`US 7,531,960 B2
`
`Page 3
`
`E.F, Gibbonset al., “Some Factors Influencing the Luminous Decay
`Characteristics ofY3 AISO12:Ce34”", J. Electrochem. Soc., vol. 120,
`No. 6, Jun. 1973.
`
`D.J. Robbins et al., “Lattice Defects and Energy Transfer Phenomena
`in Y3AISO12:Ce3+”, pp. 1004-1013, printed Jun. 19, 2001.
`“White LED lamp: Efficient light-emitting; Manufacture cost half’,
`Nikkei Sangyo Shimbun, Sep. 13, 1996, Published by Nihon Keizai
`Shimbunsha.
`
`H. Shinodaet al., Color Research & Application, vol. 18, No. 5, Oct.
`1993, pp. 326-333.
`M. Ikeda, Journal of the Illumination Society, vol. 71, No. 10, 1987,
`pp. 612-617 and English Abstract.
`P. Schloueret al. “Luminescence Conversion of Blue Light Emitting
`Diodes”, Applied Physics Letter, vol. 46, p. 417-418, Feb. 1997.
`M.F.Yan et al., Preparation ofY3 AlISO12-Based Phosphor Powders,
`J, Electrochem. Soc., vol, 134, No. 2, Feb. 1987,
`“Proceedings ofthe Institute of Phosphor Society”, Translation of pp.
`1, 5 to 14 of the 264th Proceedings ofthe Institute of Phosphor
`Society, Nov. 29, 1996.
`Shigeo Shionoyaet al, (editors), “Phosphor Handbook”, pp. 505-508,
`CRCPress, 1999,
`
`Fluorescence of
`“On The
`al.
`et
`Jr.
`W.W. Holloway,
`Cerium—Activated Garnet Crystals”, Physics Letters, vol. 25A, No.
`8, Oct. 23, 1967, pp. 614-615.
`E.F, Gibbons et al., “Some Factors Influencing the Luminous Decay
`Characteristics ofY3AISO12:Ce3+”, J. Electrochem. Soc., vol. 120,
`No. 6.
`W.J. Miniscalco etal,, “Measurements of Excited-State Absorption
`in Ce3+:YAGa)", J. Appl. Phys. vol. 49, No. 12, Dec. 1978, pp.
`6109-6111.
`D.J. Robbins et al., “Lattice Defects and Energy Transfer Phenomena
`in Y3AISO12:Ce3+”, pp. 1004-1013.
`J.M. Robertson, et al., “Colourshift of the Ce3+ Emission in
`Monocrystalline Epitaxially Grown Garnet Layers”, 1981 Philips J.
`Res. 36, pp. 15-30.
`“Nichia Chemical starts the sample shipment of white light emitting
`diode”, News Report, translation of p. 15 of Nikkei Electronics Sep.
`23, 1996 (No. 671).
`Tadao Miura, Electronics Engineering, “High-intensity White
`Backlighting for LCD of Car Audios”, Jul. 1996, vol. 38, No. 7, pp.
`55-58,
`Shigeo Shionoyaetal. (editors), “Phosphor Handbook”, pp. 505-508,
`CRC Press.
`Shuji Nakamura, “InGaN/AlGaN blue-light-emitting diodes”, J. Vac.
`MLF.Yan et al., Preparation ofY3 A150 12-Based Phosphor Powders,
`J. Electrochem. Soc., vol. 134, No. 2.
`Sci. Technol. A 13(3), May/Jun. 1995, pp. 705-710.
`“Proceedings ofthe Institute of Phosphor Society”, Translation of pp.
`Shuji Nakamura et al., “Si-Doped InGaN Films Grown on GaN
`1, 5 to 14 of the 264th Proceedings ofthe Institute of Phosphor
`Films”, Jpn. J. Appl. Phys. vol. 32 (1993), pp. L16-L19, Part 2, No.
`LA/B, Jan. 15, 1993.
`Society.
`“A New Phosphor for Flying-Spot Cathode-Ray Tubes for Color
`“P-GaN/N-InGaN/N-GaN Double-
`al,
`et
`Shuji Nakamura
`Television: Yellow Emitting ...’, G,. Blasse et al.,App. Phys. Lett.
`Heterostructure Blue-Light-Emitting Diodes”, Jpn. J. Appl. Phys.
`vol. 11, No. 2, pp. 53-55 (1967).
`vol, 32 (1993), pp, L8-L 11, Part 2, No. LA/B, Jan. 15 1993.
`Glasse et al., Applied Physics Letters, vol. Ll, No. 2. pp. 53-54
`Shuji Nakamura, “Zn-doped InGaN growth and InGaN/AlGaN
`(1967).
`double-heterostructure blue-light-emitting diodes”, Journal of Crys-
`Hoffman, Journal ofles, pp. 89-91 (1977).
`tal Growth, 145 (1994), pp. 911-917.
`Nakamura, SPIE, vol. 3002, pp. 26-35 (1997).
`
`Shuji InGaN/AlGaN—Double-Nakamura, “High-Power
`
`
`“Simens SMTI-TOPLED fur die Oberflachenmontage” Frank
`Heterostructure Blue-Light-Emitting Diodes”,
`IEDM 94 (1994),
`Mollmeret al. Simens Components, 29 (1991) Hfet 4.
`IEEE,pp. 567-570.
`“GaNpn Contact Blue/Ultraviolet light Emitting Diode”, H. Amano
`Kozo Osamura et al., “Preparation and optical properties of Gal-
`et al., Applied Physics, vol. 20, No. 2, pp. 163-166 (1991),
`xInxN thin films”, Journal of Applied Physics, vol. 46, No. 8, Aug.
`“Phosphors Based on Rare-Earths, A NewEra in Fluorescent Light-
`1975, pp. 3432-3437,
`ing”, B.M.J. Smets, Materials Chemistry and Physics, 16 pp. 283-299
`‘Takashi Matsuoka et al., “Growth and Properties of a Wide-Gap
`(1987).
`Semiconductor InGaN”, Optoelectronics-Devices and Technologies,
`W.W. Holloway, Jr. et al., “Optical Properties of Cerium-Activated
`vol. 5, No. 1, pp. 53-64, Jun. 1990,
`Garnet Crystals”, 1969 Journal of the Optical Society of America,
`'T. Nagatomoet al., “Gal-xlnxN Blue Light-Emitting Diodes”, Proc.
`vol. 59, No. 1, pp. 60-63.
`Electrochem. Soc., 1993, vol. 93-10, pp. 136-141.
`Wustlich Mikro-/Opto-Elektronik GMBH(1994/1995).
`G, Blasseet al,, “Investigation of Some Ce3+-Activated Phosphors”,
`Sato et al., Japanese Journal of Applied Physics, vol. 35, Jul. 1, 1996,
`Journal of Chemical Physics, vol. 47, No. 12, Dec. 15, 1967.
`pp. L838-L839.
`
`TCL 1036, Page 3
`LOWES 1036, Page 3
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`

`

`US 7,531,960 B2
`
`U.S. Patent
`
`May12, 2009
`
`Sheet 1 of 19
`
`
`
`203
`
`201MS YY
`
`
`
`
`
`
`SS
`
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`
`
`
`
`TCL 1036, Page 4
`LOWES 1036, Page 4
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`LOWES 1036, Page 4
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`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet 2 of 19
`
`US 7,531,960 B2
`
`Relative 50 HH intensity
`
`E
`
`0
`200
`
`ECHRESE
`EERECEREHSL
`400
`500
`
`300
`
`(%)
`
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`
`Wavelength (A)
`
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`
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`
`TCL 1036, Page 5
`LOWES 1036, Page 5
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`LOWES 1036, Page 5
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`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet 3 of 19
`
`US 7,531,960 B2
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`
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`TCL 1036, Page 6
`LOWES 1036, Page 6
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`LOWES 1036, Page 6
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`

`U.S. Patent
`
`May12, 2009
`
`Sheet4 of 19
`
`US 7,531,960 B2
`
`100 ae
`
`Srartee
`
`Relative 50
`intensity
`(%)
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`
`TCL 1036, Page 7
`LOWES 1036, Page 7
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`LOWES 1036, Page 7
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`

`U.S. Patent
`
`May12, 2009
`
`Sheet 5 of 19
`
`US 7,531,960 B2
`
`6Fig
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`LOWES 1036, Page 8
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`LOWES 1036, Page 8
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`U.S. Patent
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`May12, 2009
`
`Sheet6 of 19
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`US 7,531,960 B2
`
`Fig.7
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`TCL 1036, Page 9
`LOWES 1036, Page 9
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`LOWES 1036, Page 9
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`

`U.S. Patent
`
`May12, 2009
`
`Sheet7 of 19
`
`US 7,531,960 B2
`
`Fig. 10
`
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`(CPU)
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`
`TCL 1036, Page 10
`LOWES 1036, Page 10
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`LOWES 1036, Page 10
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`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet8 of 19
`
`US 7,531,960 B2
`
`Fig.11
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`TCL 1036, Page 11
`LOWES 1036, Page 11
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`LOWES 1036, Page 11
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`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet 9 of 19
`
`US 7,531,960 B2
`
`FId. 7 3A
`
`Life test
`
`lf=20mA Ta=25'C
`
`Relative
`power
`(%
`
`100
`
`80
`gy
`
`40
`
`20
`
` 120
`
`°9=~2000Sss4000—«i«wD.S=«iD—SC*«S 000
`
`Lighting time (H)
`
`Life test
`lf=20mA Ta=60°C 9026RH
`
`FiIg. 13B
`
`120
`
`100
`
`\
`
`89
`Relative
`power
`(%)
`
`accaMEccscecllaseieNeral
`0
`200
`400
`600
`800
`1000
`
`Lighting time (H)
`
`TCL 1036, Page 12
`LOWES 1036, Page 12
`
`LOWES 1036, Page 12
`
`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet 10 of 19
`
`US 7,531,960 B2
`
`Fig.14A
`
`Brightness
`holding rate
`%4)
`
`100
`
`80
`
`40
`
`20
`
`0
`
`Weathering test
`
`
`
`200
`
`400
`
`600
`
`Time (hr)
`
`Fig.14B
`
`0.38
`
`0.34
`
`Y
`
`0.30
`
`0.26
`
`0.22
`
`
`
`0.24
`
`0.28
`
`0.32
`
`0.36
`
`TCL 1036, Page 13
`LOWES 1036, Page 13
`
`LOWES 1036, Page 13
`
`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet 11 of 19
`
`US 7,531,960 B2
`
`g J.
`Fig. 15A
`
`Brightness
`holding rate
`(%)
`
`120
`
`100
`
`80
`
`40
`
`20
`
`0
`
`Reliability test
`
`
`
`500
`
`1000
`
`Time (hr)
`
`Fig.15B
`
`Y
`
`0.38
`
`0.34
`
`0.30
`
`0.26
`
`Ohr
`
`-
`
`PA
`
`roe
`
`Ohr
`
`/
`1000hr
`
`Ps
`
`¢
`
`¢
`
`4
`1000hr
`
`
`
`0.24
`
`0.28
`
`0.32
`
`0.36
`
`TCL 1036, Page 14
`LOWES 1036, Page 14
`
`LOWES 1036, Page 14
`
`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet 12 of 19
`
`US 7,531,960 B2
`
`seydsoud-DVA
`
`ga1-enl¢
`
`9,B14
`
`TCL 1036, Page 15
`LOWES 1036, Page 15
`
`LOWES 1036, Page 15
`
`

`

`U.S. Patent
`
`oyMay 12
`
`, 2009
`
`Sheet 13 of 19
`
`US 7,531,960 B2
`
`Jeydsoud
`
`jus}uo0D
`
`%09
`
`
`
`yUS]UODJeUdsSOUY
`
`960€
`
`%08
`
`
`jua]uo0dJaudsoug
`4qatenig
`
`TCL 1036, Page 16
`LOWES 1036, Page 16
`
`LOWES 1036, Page 16
`
`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet14 of 19
`
`US 7,531,960 B2
`
`
`
`
`
`if—-—L7++—oy
`Fig. 78B
`Wavelength (nm)
`
`
`580
`630
`680
`730
`
`530
`
` 7
`
` 0
`
`380
`
`430
`
`480
`
`
`
`
`
`
`
`
`530
`
`580
`
`630
`
`680
`
`730
`
`430
`
`480
`
`03
`
`80
`
`Fig 1 8GC
`
`Wavelength (nm)
`
`
`
`
`
`
`
`
`
`
`
`380
`
`430
`
`480
`
`530
`580
`Wavelength (nm)
`
`630
`
`680
`
`730
`
`TCL 1036, Page 17
`LOWES 1036, Page 17
`
`LOWES 1036, Page 17
`
`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet 15 of 19
`
`US 7,531,960 B2
`
`380
`
`430
`
`480
`
`530
`
`580
`
`#630
`
`680
`
`730
`
`Fig. 79B
`
`Wavelength (nm)
`
`
`
`
`
`
`
`
`
` 0
`100
`
`
`
`
`
`
`
`
`
`
`
`0
`380
`
`430
`
`480
`
`530
`580
`Wavelength (nm)
`
`630
`
`680
`
`730
`
`TCL 1036, Page 18
`LOWES 1036, Page 18
`
`LOWES 1036, Page 18
`
`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet 16 of 19
`
`US 7,531,960 B2
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`"380
`Fig.2OC
`
`430
`
`480
`
`#630
`
`680
`
`730
`
`580
`530
`Wavelength (nm)
`
` 380
`
`100
`
`
`
`
`
`
`
`
`
`
`
`
`
`430
`
`480
`
`530 i630
`
`680
`
`730
`
`Wavelength (nm)
`
`TCL 1036, Page 19
`LOWES 1036, Page 19
`
`LOWES 1036, Page 19
`
`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet 17 of 19
`
`US 7,531,960 B2
`
`
`
`
`
`
`
`
`
`"380
`Fig.PIB
`
`430
`
`480
`
`580
`5380
`Wavelength (nm)
`
`#630
`
`680
`
`730
`
`
`
`
`
`
` 0380
`int —MmWw[T0000
`
`430 i 530
`
`580
`
`630
`
`680
`
`730
`
`Wavelength (nm)
`
`
`
`
`
`
`© 50
`
`
` Relative
`
`380
`
`430
`
`480
`
`530
`
`580
`
`630
`
`680
`
`730
`
`Wavelength (nm)
`
`TCL 1036, Page 20
`LOWES 1036, Page 20
`
`LOWES 1036, Page 20
`
`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet18 of 19
`
`US 7,531,960 B2
`
`
`
` 0
` 0
` 0
`
`380
`
`430
`
`480
`
`530
`
`580
`
`630
`
`680
`
`730
`
`Fig.22B
`
`Wavelength (nm)
`
`
`
`380
`
`430
`
`480
`
`530
`
`580
`
`630
`
`680
`
`730
`
`Fig.22DC
`
`Wavelength (nm)
`
`
`
`380
`
`8430
`
`480
`
`530
`
`580
`
`630
`
`680
`
`730
`
`Wavelength (nm)
`
`TCL 1036, Page 21
`LOWES 1036, Page 21
`
`LOWES 1036, Page 21
`
`

`

`U.S. Patent
`
`May12, 2009
`
`Sheet 19 of 19
`
`US 7,531,960 B2
`
`450900550600650700750
`
`400
`
`350
`
`
`
`Wavelength(nm)
`
`Fig.23
`
`100
`
`a
`
`5
`co
`
`°
`+
`
`o
`Mw
`
`o
`
`Relative intensity (%)
`
`TCL 1036, Page 22
`LOWES 1036, Page 22
`
`LOWES 1036, Page 22
`
`

`

`US 7,531,960 B2
`
`1
`LIGHT EMITTING DEVICE WITH BLUE
`LIGHT LED AND PHOSPHOR COMPONENTS
`
`This application is a 37 C.F.R. § 1.53(b) divisional of U.S.
`application No. 10/609,402, filed Jul. 1, 2003, nowU.S. Pat.
`No. 7,362,048 whichis a divisional of U.S. application Ser.
`No. 09/458,024, filed Dec. 10, 1999, nowU.S. Pat. No. 6,614,
`179 whichis a divisional ofU.S. application Ser. No. 09/300,
`315, filed on Apr. 28, 1999, now U.S. Pat. No. 6,069,440,
`whichis a divisional of U.S. application Ser. No. 08/902,725,
`filed on Jul. 29, 1997, nowU.S. Pat. No. 5,998,925, the entire
`contents of which are hereby incorporated byreference.
`
`wn
`
`1
`
`BACKGROUNDOF THE INVENTION
`
`1. Field of the Invention
`
`ba
`
`‘The present inventionrelates to a light emitting diode used
`in LEDdisplay, back light source,
`traffic signal, trailway
`signal, illuminating switch, indicator, etc. More particularly,
`it relates to a light emitting device (LED) comprising a phos-
`phor, which converts the wavelength oflight emitted by a
`light emitting component and emits light, and a display
`device using the light emitting device.
`2. Description of Related Art
`A light emitting diode is compact and emits light ofclear
`color withhighefficiency.It is also free from suchatrouble as
`burn-out and has goodinitial drive characteristic, high vibra-
`tion resistance and durability to endure repetitive ON/OFF
`operations, becauseit is a semiconductor element. Thus it has
`been used widely in such applications as various indicators
`and various light sources. Recently light emitting diodes for
`RGB(red, green and blue) colors having ultra-high lumi-
`nance and high efficiency have been developed, and large
`screen LED displays using these light emitting diodes have
`beenput into use. The LED display can be operated withless;
`power and has such good characteristics as light weight and
`longlife, and is therefore expected to be more widelyused in
`the future.
`
`3
`
`AC
`
`Recently, various attempts have been made to make white
`light sources byusing light emitting diodes. Because the light
`emitting diode has a favorable emission spectrumto generate
`monochromatic light, making a light source for white light
`requires it to arrange three light emitting components of R, G
`and B closely to each other while diffusing and mixing the
`light emitted by them. Whengenerating white light with such
`an arrangement, there has been such a problem that white
`light of the desired tone cannot be generated duetovariations
`in the tone, luminance and other factors ofthe light emitting
`component. Also when the light emitting components are
`madeofdifferent materials, electric power required for driv-
`ing differs fromonelight emitting diode to another, making it
`necessaryto apply different voltages different light emitting
`components, whichleads to 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, chrono-
`logical changes and operating environment, or unevennessin
`color may be caused due to failure in uniformly mixing the
`light enutted by the light emitting components. Thus light
`emitting diodes are effective as light emitting devices for
`generating individual colors, although a satisfactory light
`source capable of emitting white light byusing light emitting
`components has not been obtained so far.
`In order to solve these problems, the present applicant
`previously developed light emitting diodes which convert the
`color of light, which is emitted by light emitting components,
`by means of a fluorescent material disclosed in Japanese
`
`50
`
`60
`
`2
`Patent Kokai Nos, 5-152609, 7-99345, 7-176794 and 8-7614.
`The light emitting diodes disclosed in these publications are
`suchthat, by using light emitting components ofone kind, are
`capable ofgenerating light of white and other colors, and are
`constituted as follows.
`
`Thelight emitting diode disclosed inthe above gazettes are
`made by mounting a light emitting component, having a large
`energy band gap of light emitting layer, in a cup provided at
`the tip ofa lead frame, and having a fluorescent material that
`absorbs light emitted by the light emitting component and
`emits light ofa wavelengthdifferent fromthat ofthe absorbed
`light (wavelength conversion), contained in a resin mold
`which covers the light emitting component.
`The light emitting diode disclosed as described above
`capable of emitting white light by mixing the light ofa plu-
`rality of sources can be madeby using a light emitting com-
`ponent capable of emitting blue light and molding the light
`emitting component with a resin including a fluorescent
`material that absorbs the light emitted by the blue light emit-
`ting diode and emits yellowish light.
`However, conventional
`light emitting diodes have such
`problemsas deterioration ofthe fluorescent material leading
`to color tone deviationand darkening ofthe fluorescent mate-
`rial resulting in lowered efficiency ofextracting light. Dark-
`ening hererefers to, in the case ofusing an inorganic fluores-
`cent material such as (Cd, Zn)S fluorescent material, for
`example, part of metal elements constituting the fluorescent
`material precipitate or changetheir properties leading tocol-
`oration, or, in the case of using an organic fluorescent mate-
`rial, coloration due to breakage of double bond in the mol-
`ecule. Especially whena light emitting component madeofa
`semiconductor having a high energy band gap is used to
`improve the conversionefficiency of the fluorescent material
`(that is, energy of light emitted by the semiconductor is
`increased and number of photons having energies above a
`threshold which can be absorbed by the fluorescent material
`increases, resulting in more light being absorbed), or the
`quantity of fluorescent material consumption is decreased
`(that is, the fluorescent material is irradiated withrelatively
`higher energy),
`light energy absorbed by the fluorescent
`material
`inevitably increases resulting in more significant
`degradationof the fluorescent material. Use of the light emit-
`ting component with higherintensity of light emissionfor an
`extended period oftime causes further more significant deg-
`radation ofthe fluorescent material.
`
`Also the Nuorescent material providedin the vicinity of the
`light emitting component maybe exposed to ahigh tempera-
`ture suchas rising temperature ofthe light emitting compo-
`nent and heat transmitted fromthe external environment(for
`example, sunlight in case the device is used outdoors).
`Further, some fluorescent materials are subject to acceler-
`ated deterioration due to combination of moisture entered
`from the outside or introduced during the productionprocess,
`the light and heat transmitted fromthe light emitting compo-
`nent.
`
`Whenit comes to an organic dye ofionic property, direct
`current electric field in the vicinity of the chip may cause
`electrophoresis, resulting in a change inthe color tone.
`
`SUMMARY OF THE INVENTION
`
`Thus, an object of the present invention is to solve the
`problemsdescribed above and provide a light emitting device
`which experiences only extremely lowdegrees ofdeteriora-
`tion in emissionlight intensity, light emission efficiency and
`color shifi over a long time of use with high luminance.
`TCL 1036, Page 23
`LOWES 1036, Page 23
`
`LOWES 1036, Page 23
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`

`

`US 7,531,960 B2
`
`3
`invention
`The present applicant completed the present
`throughresearches based on the assumptionthat a light emit-
`ting device having alight emitting component and afluores-
`cent material must meet
`the following requirements to
`achieve the above-mentioned object.
`The light emitting component must be capable ofemitting
`light of high luminance with light emitting characteristic
`whichis stable over a long time ofuse.
`The fluorescent material being provided in the vicinity of
`the high-luminance light emitting component, must show
`excellent resistance against light and heat so that the proper-
`ties thereof do not change even whenused over an extended
`period of time while being exposed tolight of highintensity
`emitted by the light emitting component (particularly the
`fluorescent material provided inthe vicinity ofthe light emit-
`ting componentis exposed to light ofa radiation intensity as
`high as about 30to 40 timesthat of sunlight according to our
`estimate, and is required to have more durability against light
`as light emitting component ofhigher luminanceis used).
`With regard to the relationship withthe light emitting com-
`ponent, the fluorescent material must be capable of absorbing
`withhighefficiencythe light of high monochromaticity emit-
`ted by the light emitting component and emitting light of a
`wavelengthdifferent from that of the light emitted by the light
`emitting component.
`Thus the present invention providesa light emitting device,
`comprising a light emitting component and a phosphor
`capable of absorbing a part of light emitted by the light
`emitting component and emitting light of wavelengthdiffer-
`ent fromthat ofthe absorbed light;
`whereinsaid light emitting component comprises a nitride
`compound semiconductorrepresented by the formula: In,Ga,
`Al,N where 0=1, 0Sj, OSk and i+j+k=1) and said phosphor
`contains a garnet fluorescent material comprising at least one
`element selected fromthe group consisting ofY, Lu, Se, La,
`Gd and Sm, andat least one element selected fromthe group
`consisting of Al, Ga and In, and being activated with cerium.
`The nitride compound semiconductor (generally repre-
`sented by chemical formula In,Ga,Al,N where 021, 0S},
`OSk and i+j+k=1) mentioned above contains various mate-
`rials including InGaN and GaN doped with various impuri-
`lies.
`
`wn
`
`ay
`
`2
`
`3
`
`ae va
`
`AC
`
`The phosphor mentioned above contains various materials
`defined as described above,
`including Y,Al,O,5:Ce and
`Gd,In,O, 5:Ce.
`Becausethe light emitting device ofthe present invention
`uses the light emitting component made ofa nitride com-
`pound semiconductor capable of emitting light with high
`wn
`luminance, the light emitting device is capable of emitting 5
`light with high luminance. Alsothe phosphor used in the light
`emitting device has excellent resistance against light sothat
`the fluorescent properties thereofexperience less change even
`when used over an extended period of time while being
`exposed to light ofhigh intensity. This makes it possible to
`reduce the degradation ofcharacteristics during long period
`of use and reduce deterioration due to light of high intensity
`emitted bythe light emitting componentas well as extraneous
`light (sunlight including ultraviolet light, etc.) during outdoor
`use, thereby to provide a light emitting device which experi-
`ences extremelyless color shift and less luminance decrease.
`The light emitting device ofthe present invention can also be
`usedin suchapplications that require response speedsas high
`as 120 nsec., for example, because the phosphor used therein
`allows after glowonly for a short period oftime.
`‘The phosphorused inthelight emitting diode ofthe present
`invention preferably contains an yttrium-aluminum-garnet
`
`wn on
`
`6f
`
`4
`fluorescent material that contains Y and Al, which enablesit
`to increase the luminanceofthe light emitting device.
`In the light emitting device of the present invention, the
`phosphor may be a fluorescent material represented bya
`general
`formula
`(Re,_,Sm,),(Al,_,Ga,);O,5:Ce, where
`O0=r<! and 0=s=1 and Reis at least one selected from Y and
`Gd, in which case good characteristics can be obtained simi-
`larly to the case where the yttrium-aluminum-garnetfluores-
`cent material is used.
`
`Alsoin the light emitting device of the present invention, it
`is preferable, for the purpose of reducing the temperature
`dependenceoflight emission characteristics (wavelength of
`emitted light, intensity oflight emission, etc.), to use a fluo-
`rescent material represented by a general formula (Y,_,.,.,.
`Gd,,Ce,Sm,.),(Al,_,Ga,);0,;,
`as
`the
`phosphor, where
`0=p=0.8, 0.003=q=0.2, 0.0003 =r=0.08 and 0Ss=1.
`Alsoin the light emitting device of the present invention,
`the phosphor may contain two or more yttrium-aluminum-
`garnet fluorescent materials, activated with cerium, ofdiffer-
`ent compositions including Y and Al. Withthis configuration,
`light of desired color can be emitted by controlling the emis-
`sion spectrum of the phosphor according to the property
`(wavelength of emitted light) of the light emitting compo-
`nent.
`
`Further in the light emitting device of the present invention,
`in orderto havelight ofa specified wavelength emitted bythe
`light emitting device,it is preferable that the phosphor con-
`tains two or more fluorescent materials ofdifferent composi-
`tions represented by general formula (Re,_,Sm,.),;(Al,_,Ga,)5
`O,.:Ce, where 0=r=1 and 0Ss=1 and Reis at least one
`selected from Y and Gd.
`
`Alsointhe light emitting device ofthe present invention, in
`orderto control the wavelength of emitted light, the phosphor
`may contain afirst fluorescent material represented by gen-
`eral formula Y,(Al, sGas).O,,:Ce and a second fluorescent
`material
`represented by general
`formula Re,Al,O,,:Ce,
`where 0Ss=1 andReis at least one selected from Y. Gd and
`La.
`
`Alsoin the light emitting device ofthe present invention, in
`order to control the wavelengthofemitted light, the phosphor
`may be an yttrium-aluminum-garnet
`fluorescent material
`containing afirst fuorescent material and a secondfiuores-
`cent material, with different parts of each yttrium being sub-
`stituted with gadolinium.
`Furtherinthe light emitting device ofthe present invention,
`it is preferable that main emission peak of the light emitting
`component is set within the range from 400 nmto 530 nmand
`main emission wavelengthof the phosphor is set to be longer
`than the main emission peak ofthe light emitting component.
`This makesit possible to efficiently emit white light.
`Furtherinthe light emitting device ofthe present invention,
`it is preferable that the light emitting layer ofthe light emit-
`ling component contains a gallium nitride semiconductor
`whichcontains In, and the phosphor is an yttrium-aluminum-
`garnetfluorescent material whereina part of Al in the yttrium-
`aluminum-garnet fluorescent is substituted by Ga sothat the
`proportion of Ga:Alis withinthe range from1:1 to 4:6 anda
`part of Y in the yttrium-aluminum-garnet fluorescentis sub-
`stituted by Gd sothat the proportion of Y:Gd is within the
`range from4:1 to 2:3. Absorption spectrumof the phosphor
`whichis controlled as described above shows good agree-
`ment with that oflight emitted bythe light emitting compo-
`nent which contains galliumnitride semiconductor including
`In as the light emitting layer, and is capable of improving the
`conversion efficiency (light emission efficiency). Also the
`light, generated by mixing blue light emitted bythe light
`emitting component and fluorescent light of the fluorescent
`TCL 1036, Page 24
`LOWES 1036, Page 24
`
`LOWES 1036, Page 24
`
`

`

`US 7,531,960 B2
`
`6
`sitions represented by a general formula (Re,_,Sm,.),(Al,_,
`Ga,);O,2:Ce, where 0=r<1 and 0Ss=1 and Reis at least one
`selected from Y and Gd maybe used as the phosphorin order
`to control the emittedlight to a desired wavelength.
`In the light emitting diode of the present invention, simi-
`larly, a first fluorescent material represented by a general
`formula Y,(Al,_,Ga,).O, ,:Ce and a second fluorescent mate-
`rial represented by a general formula Re,Al,O,.:Ce, may be
`used as the phosphor where 0=s=1 and Reis at least one
`selected from Y, Gd and La, in order to control the emitted
`light to a desired wavelength.
`In the light emitting diode ofthe present invention, simi-
`larly, yttrium-aluminum-garnet fluorescent material a first
`fluorescent mate