USOO7479731B2 (12) United States Patent (10) Patent No.: US 7479,731 B2 Udagawa (45) Date of Patent: Jan. 20, 2009 (54) MULTICOLOR LIGHT-EMITTING LAMP (58) Field of Classification Search .................. 313/409 AND LIGHT SOURCE See application file for complete search history. (75) Inventor: Takashi Udagawa, Chichibu (JP) (56) References Cited (73) Assignee: Showa Denko K.K., Tokyo (JP) U.S. PATENT DOCUMENTS 4.322,735 A 3/1982 Sadamasa et al. ............. 257/89 (*) Notice: Subject to any disclaimer, the term of this 4,929,866 A * 5, 1990 Murata et al................ 313,500 patent is extended or adjusted under 35 5,005,057 A 4/1991 Izumiya et al. U.S.C. 154(b) by 206 days. 5,042,043 A 8, 1991 Hatano et al. 5,324.962 A 6/1994 Komoto et al. 21) Appl. No.: 10/486,985 (21) App 9 (Continued) (22) PCT Filed: Aug. 16, 2002 FOREIGN PATENT DOCUMENTS (86). PCT No.: PCT/UP02/08317 DE 19734034 A1 2, 1998 S371 (c)(1), (Continued) (2), (4) Date: Feb. 18, 2004 Primary Examiner Sikha Roy (87) PCT Pub. No.: WO03/017387 Assistant Examiner Natalie KWalford (74) Attorney, Agent, or Firm Sughrue Mion, PLLC PCT Pub. Date: Feb. 27, 2003 (57) ABSTRACT (65) Prior Publication Data The present invention provides a technique for fabricating a US 2004/O183089 A1 Sep. 23, 2004 multicolor light-emitting lamp by using a blue LED having a structure capable of avoiding cumbersome bonding. In par Related U.S. Application Data ticular, the present invention provides a technique for fabri (60) Provisional application No. 60/323,088, filed on Sep. cating a multicolor light-emitting lamp by using a hetero 19, 2001. junction type GaP-base LED capable of emitting high intensity green light in combination. Also, for example, in (30) Foreign Application Priority Data fabricating a multicolor light-emitting lamp from the blue Aug. 20, 2001 (JP) ............................. 2001-24.8455 LED and the yellow LED, the present invention provides a technique for fabricating a multicolor light-emitting lamp (51) Int. Cl. from a blue LED requiring no cumbersome bonding and a HOL L/62 (2006.01) hetero-junction type GaAS2P-base yellow LED of emitting HOI 63/04 (2006.01) light having high light emission intensity. (52) U.S. Cl. ....................... 313/499; 313/500; 313/501; 313/483 15 Claims, 4 Drawing Sheets 2A 1A e M 8. N aaaaaaaaaaaaa ZZ - ZZZZY SS - SS SSSSSSS 107 US 7,479,731 B2 Page 2 U.S. PATENT DOCUMENTS GB 2316226 A 2, 1998 JP 54-33748 A 3, 1979 5,375,043 A * 12/1994 Tokunaga ................... 362/601 p. 2-288388 11, 1990 5,886,367 A 3/1999 Udagawa JP 4-209584 7, 1992 6,069,021 A * 5/2000 Terashima et al. ............ 257/13 JP 5-283744 A 10, 1993 6,110,757 A 8/2000 Udagawa JP 10-562O2 2, 1998 6,220,722 B1* 4/2001 Begemann .................. 362.231 10-242567 9, 1998 6,936,863 B2 * 8/2005 Udagawa et al. .. ... 438/47 7,030.003 B2 * 4/2006 Udagawa .................... 438/604 JP 2000-12896. A 1, 2000 JP 2000-584.51 2, 2000 FOREIGN PATENT DOCUMENTS EP 395392 A2 10, 1990 * cited by examiner U.S. Patent Jan. 20, 2009 Sheet 1 of 4 US 7479,731 B2 Fig. 1 N-106 SOAS SO2S 107 Fig. 2 N-106 21052 N104N NN 3 107 U.S. Patent Jan. 20, 2009 Sheet 2 of 4 US 7479,731 B2 N-106 Z105Z 2.10% 06 N U.S. Patent Jan. 20, 2009 Sheet 3 of 4 US 7479,731 B2 N %2% 1AN- N N N %5%SS M s aaaaaaaaaaaaaaaaaaaa2211/222a12222222 ES 15 SS 2A 1A 2A %108% /1 N SNSS-SS è& N. 107 107 107 U.S. Patent Jan. 20, 2009 Sheet 4 of 4 US 7479,731 B2 Fig. 7 30 N 21052 ZiO52 NOAN N104N S192S W1012 NY2 aa ZadaaZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ 15 NY Fig. 8 18 4A o oooooooo oo o o o US 7,479,731 B2 1. 2 MULTICOLOR LIGHT-EMITTING LAMP single crystal) as the Substrate material (see, III Zoku AND LIGHT SOURCE Chikkabutsu Handotai (Group III Nitride Semiconductor), pages 243 to 252, Supra). Since a current (operating current) This application claims benefit of Provisional Application for driving the LED cannot be passed through the insulating No. 60/323,088 filed Sep.19, 2001, the disclosure of which is 5 crystal Substrate, both of positive and negative electrodes are incorporated herein by reference. disposed in the same surface side of the substrate. On the TECHNICAL FIELD other hand, the homo-junction type GaP-base or homo-junc tion type GaAS2P-base LED is fabricated by using an The present invention relates to a technique for fabricating 10 electrically conducting gallium phosphide (GaP) single crys a multicolor light-emitting lamp which uses a plurality of tal or gallium arsenide (GaAs) single crystal and therefore, light-emitting diodes (LED) and can emit multiple colors only one electrode having either positive polarity or negative different in the wavelength. polarity is disposed in the surface side (see, Handotai Device BACKGROUND ART Gairon (Outline of Semiconductor Device), page 117, supra). 15 In any case, when an RGB three color integration-type A technique of fabricating an RGB-type multicolor light white lamp is fabricated by using conventional Gan N emitting lamp by adjacently disposing light-emitting diodes (0sXs 1)-base blue, green and red LEDs each comprising an (LED) capable of emitting each color of red light (R), green insulating crystal Substrate, both electrodes of positive polar light (G) and blue light (B) which are the three primary colors ity and negative polarity are disposed on the Surface of each oflight has been heretofore known. For example, a technique LED, therefore, wire bonding to electrodes of one polarity of fabricating an RGB-type multicolor light-emitting lamp by and wire bonding to electrodes of another polarity must be integrating an LED (blue LED) of emitting blue band light separately performed and this is cumbersome. If the polarity having a light emission wavelength of 450 nm, a green LED of the electrodes to be bonded can be unified to either positive of emitting green band light having a light emission wave 25 length of around 525 nm and a red LED of emitting redband or negative by making use of an electrically conducting Sub light having a light emission wavelength of approximately strate, particularly an electrically conducting Substrate hav from 600 to 700 nm is known (see, Display Gijutsu (Display ing the same conductivity, the cumbersome bonding can be Technique), 1st ed., 2nd imp., pages 100 to 101, Kyoritsu avoided. Shuppan (Sep. 25, 1998)). 30 In recent years, a technique of fabricating a blue LED by Conventionally, a multicolor light-emitting lamp is fabri using a boron-containing group III-V compound semicon cated by using a Gan N-base blue LED (see, JP-B-55 ductor layer and a light-emitting layer composed of a group 3834) where the light-emitting layer is composed of a group III-V compound semiconductor, which are provided on an III-V compound semiconductor Such as gallium indium electrically conducting silicon single crystal (silicon), is dis nitride (Galin N: 0s)xs1) (see, III Zoku Chikkabutsu 35 closed (see, U.S. Pat. No. 6,069,021). If a blue LED using an Handotai (Group III Nitride Semiconductor), pages 252 to electrically conducting Substrate having the same conductiv 254, Baifukan (Dec. 8, 1999)). For the green LED, a Ga ity as the substrate used for the fabrication of a green or red In N green LED or a homo-junction type GaP green LED, LED is used, an RGB-type multicolor light-emitting lamp can which has gallium phosphide as a light-emitting layer, is used be readily fabricated without incurring cumbersome bonding (see, (1) III Zoku Chikkabutsu Handotai (Group III Nitride 40 operation as in conventional techniques. Semiconductor), pages 249 to 252, supra, and (2) III-V Zoku Kagobutsu Handotai (Group III-V Compound Semiconduc On the other hand, the GaP-base or GaAsP-base LED tor), 1st ed., pages 253 to 261, Baifukan (May 20, 1994)). For constituting the multicolor light-emitting lamp together with the red LED, an LED having a light-emitting layer composed the Gal-In-N-base blue LED has a homo-junction type of a group III-V compound semiconductor Such as aluminum 45 structure. Therefore, the light emission intensity of the GaP gallium arsenide mixed crystal (AlGaAS: 0<X-1) or alu base or GaAsP-base LED is lower than that of the Ga minum gallium indium phosphide ((AlGa). In-P: In N (0sXs 1) double hetero (DH)-junction type LED, OsXs 1, 0<Y<1) is used (see, Iwao Teramoto, Handotai failing in providing a multicolor light-emitting lamp well Device Gairon (Outline of Semiconductor Device), pages balanced in view of the light emission intensity. If a hetero 116 to 118, Baifukan (Mar. 30, 1995)). 50 junction type structure capable of exerting a “confinement' Also, it is known that white light can be obtained by mixing effect on carrier to cause light emission by radiation recom complementary colors, for example, blue band light and yel bination is formed, this is expected to bring higher intensity low band light (see, Hikari no Enpitsu-Hikari Gijutsusha no light emission. tame no Oyo Kogaku-(Pencil of Light-Applied Optics for The present invention provides a technique for fabricating Optical Engineer), 7th ed., page 51, Shin Gijutsu Communi 55 cations (Jun. 20, 1989)). For the yellow LED suitable to be a multicolor light-emitting lamp by using a blue LED having combined with the blue LED, a homo-junction type GaAsP a structure capable of avoiding cumbersome bonding.