Light emitting device with blue light LED and phosphor components

• US 6,614,179 B1
• Filed: 12/10/1999
• Issued: 09/02/2003
• Est. Priority Date: 07/29/1996
• Status: Expired due to Term

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Kagaku Kogyo Kabushiki Kaisha
• Inventors: Shimizu, Yoshinori, Moriguchi, Toshio, Sakano, Kensho, Noguchi, Yasunobu
• Primary Examiner(s): Patel, Vip
• Assistant Examiner(s): WILLIAMS, JOSEPH L
• Application Number:
  US09/458,024
• Time in Patent Office: 1,362 Days
• Field of Search: 313/512, 313/486, 313/489, 313/498, 313/501, 313/502, 313/493, 313/503, 313/506, 257/103, 428/690
• US Class Current: 313/512
• CPC Class Codes: C09K 11/7767 Chalcogenides
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: H01J 29/20 characterised by the luminescent material
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/45169 Platinum (Pt) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01021 : Scandium [Sc]
• CPC Class Codes: H01L 2924/01067 : Holmium [Ho]
• CPC Class Codes: H01L 2924/01068 : Erbium [Er]
• CPC Class Codes: H01L 2924/12036 : PN diode
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/15747 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/20751 : larger or equal to 10 microns less than 20 microns
• CPC Class Codes: H01L 2924/20752 : larger or equal to 20 microns less than 30 microns
• CPC Class Codes: H01L 2924/20753 : larger or equal to 30 microns less than 40 microns
• CPC Class Codes: H01L 2924/20754 : larger or equal to 40 microns less than 50 microns
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H01L 2933/0091 : Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/50 : Wavelength conversion elements
• CPC Class Codes: H01L 33/501 : characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/502 : Wavelength conversion materials
• CPC Class Codes: H01L 33/504 : Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/56 : Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H05B 33/14 : characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: Y02B 20/00 : Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

The white light emitting diode comprising a light emitting component using a semiconductor as a light emitting layer and a phosphor which absorbs a part of light emitted by the light emitting component and emits light of wavelength different from that of the absorbed light, wherein the light emitting layer of the light emitting component is a nitride compound semiconductor and the phosphor contains garnet fluorescent material activated with cerium which contains at least one element selected from the group consisting of Y, Lu, Sc, La, Gd and Sm, and at least one element selected from the group consisting of Al, Ga and In and, and is subject to less deterioration of emission characteristic even when used with high luminance for a long period of time.

Claims

1. A chip type light emitting diode which comprises a light emitting diode chip component comprising at least two adjacent Gallium Nitride compound semiconductor of different conductive types;

a metal terminal component comprising a pair of electrodes each electrically connected with said light emitting diode chip and a molding material arranged on or above a light emitting surface of said light emitting diode chip,

wherein said light emitting diode chip is capable of emitting a blue light having a main peak of 420 nm to 490 nm in wavelength and said molding material contains a phosphor represented by a general formula (Re<sub>1−

r</sub>Sm_r)₃(Al<sub>1−

s</sub>Ga_s)₅O₁₂;

Ce where 0≦

r<

1 and 0≦

s≦

1 and Re is at least one selected from Y and Gd and capable of absorbing a part of light emitted by said light emitting diode chip component and emitting light of wavelength longer than that of the absorbed light.

2. A chip type light emitting diode according to claim 1, wherein said light emitting diode chip comprises a light emitting layer of single quantum well or multi quantum well structure.

3. A chip type light emitting diode according to claim 1, wherein said light emitting diode chip comprises InGaN.

4. A chip type light emitting diode according to claim 1, wherein said phosphor is arranged on or above said light emitting diode chip so as to absorb the emitting light of radiation intensity of 3 to 10 Wcm⁻

2.

5. A chip type light emitting diode according to claim 1, wherein said Gallium Nitride compound semiconductor layers are formed on a substrate selected from the group consisting of sapphire, spinnel, SiC, Si and ZnO.

6. A chip type light emitting diode according to claim 1, wherein said molding material of a transparent material selected from the group consisting of epoxy resin, urea resin, silicone resin and glass.

7. A chip type light emitting diode according to claim 1, wherein said phosphor is represented by a general formula [(Y₁₋

aGd_a)<sub>1−

r</sub>Sm_r]₃(Al<sub>1−

s</sub>Ga_s)₅O₁₂;

Ce where o≦

r<

1 and 0≦

s≦

1 and (1−

a)/a is 2/3 to 4/1.

8. A chip type light emitting diode according to claim 1 or 6,

wherein said molding material contains the dispersant selected from the group consisting of barium titanate, titanium oxide, aluminum oxide and silicon dioxide.

9. A chip type light emitting diode according to claim 8, wherein said molding material contains the color agent.

10. A chip type light emitting diode according to claim 1, wherein said molding material contains the color agent.

11. A light emitting diode which comprises a light emitting diode chip component comprising at least two adjacent Gallium Nitride compound semiconductor of different conductive types;

a terminal component comprising a pair of electrodes each electrically connected with said light emitting diode chip and a molding material arranged on or above a light emitting surface of said light emitting diode chip,

wherein said light emitting diode chip is capable of emitting a blue light having a main peak of 420 nm to 490 nm in wavelength and said molding material contains a phosphor represented by a general formula [(Y<sub>1−

a</sub>Gd_a)<sub>1−

r</sub>Sm_r]₃(Al<sub>1−

s</sub>Ga_s)₅O₁₂;

Ce where 0≦

r<

1 and 0≦

s≦

1 and (1−

a)/a is 2/3 to 4/1 and capable of absorbing a part of light emitted by said light emitting diode chip component and emitting light of wavelength longer than that of the absorbed light.

12. A light emitting diode according to claim 11, wherein said light emitting diode comprises a light emitting layer of single quantum well or multi quantum well structure.

13. A light emitting diode according to claim 11, wherein said light emitting diode chip comprises InGaN.

14. A light emitting diode according to claim 11, wherein said phosphor in said coating component is arranged on or above said light emitting diode chip so as to absorb the emitting light of radiation intensity of 3 to 10 Wcm⁻

2.

15. A light emitting diode according to claim 11, wherein said Gallium Nitride compound semiconductor layers are formed on a substrate selected from the group consisting of sapphire, spinnel, SiC, Si and ZnO.

16. A light emitting diode according to the claim 11,

wherein said molding material is of a transparent material selected from the group consisting of epoxy resin, urea resin, silicone resin and glass.

17. A light emitting diode according to claims 11 or 16,

wherein said molding material contains the dispersant selected from the group consisting of barium titanate, titanium. oxide, aluminum oxide and silicon dioxide.

18. A light emitting diode according to claim 11, wherein said molding material contains the color agent.

19. A light emitting diode according to claim 17, wherein said molding material contains the color agent.