Light emitting device with blue light led and phosphor components

• US 20040000868A1
• Filed: 07/01/2003
• Published: 01/01/2004
• Est. Priority Date: 07/29/1996
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Kagaku Kogyo Kabushiki Kaisha
• Inventors: Shimizu, Yoshinori, Moriguchi, Toshio, Sakano, Kensho, Noguchi, Yasunobu
• Granted Patent: US 7,362,048 B2
• Time in Patent Office: Days
• 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 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 wavelength different from that of the absorbed light,

wherein a straight line connecting a point of chromaticity corresponding to a peak of the spectrum generated by the light emitting component and a point of chromaticity corresponding to a peak of the spectrum generated by the phosphor is along with the black body radiation locus in the chromaticity diagram.

2. The light emitting device according to claim 1,

wherein said light emitting component is a blue LED.

3. The light emitting device according to claim 1,

wherein said point of chromaticity corresponding to a peak of the spectrum generated by the light emitting component, said point of chromaticity corresponding to a peak of the spectrum generated by the phosphor and contents of the phosphor are adjusted so that said straight line is along with the black body radiation locus.

4. The light emitting device according to claim 1,

wherein said straight line contains a point corresponding to a color temperature of 8080K or 4400K.

5. The Light emitting device according to claim 1,

wherein main emission peak of the light emitting component is set within the range from 400 nm to 530 nm.

6. The light emitting device according to claim 1,

wherein main emission peak of the light emitting component is set within the range from 420 nm to 490 nm.

7. The light emitting device according to claim 1,

wherein main emission peak of the light emitting component is set within the range from 450 nm to 475 nm.

8. The light emitting device according to claim 1,

wherein the structure of the light emitting component is either one structure of homostructure, heterostructure and double-heterostructure which have MIS junction, PIN junction or PN junction.

9. The light emitting device according to claim 1,

wherein said light emitting component comprises an active layer having a single quantum well structure or multi quantum well structure.

10. The light emitting device according to claim 1,

wherein said phosphor is made by steps of solving rare earth elements in acid in stoichiometrical proportions, coprecipitating the solution with oxalic acid to obtain a sediment, firing the sediment to obtain an oxide, and firing a mixture of said oxide, an ammonium fluoride and aluminum oxide.

11. The light emitting device according to claim 1,

wherein emission peak of the phosphor is set within the range from 530 nm to 570 nm.