Light emitting device with blue light LED and phosphor components

• US 20070159060A1
• Filed: 03/05/2007
• Published: 07/12/2007
• Est. Priority Date: 07/29/1996
• Status: Active Grant

• Current Assignee: Kensho Sakano, Toshio Moriguchi, Yasunobu Noguchi, Yoshinori Shimizu
• Original Assignee: Kensho Sakano, Toshio Moriguchi, Yasunobu Noguchi, Yoshinori Shimizu
• Inventors: Shimizu, Yoshinori, Moriguchi, Toshio, Sakano, Kensho, Noguchi, Yasunobu
• Granted Patent: US 7,531,960 B2
• Time in Patent Office: Days
• US Class Current: 313/498
• 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

A light emitting device includes a light emitting component; and a phosphor capable of absorbing a part of light emitted by the light emitting component and emitting light of a wavelength different from that of the absorbed light. 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 disposed along with the black body radiation locus in the chromaticity diagram.

Claims

1. A light emitting device which comprises a light emitting component having a gallium nitride based semiconductor and a resin containing a phosphor capable of absorbing a part of a first light of blue color emitting from the light emitting component and emitting a second light of wavelength different from that of the absorbed first light, said emission of the second light emitted from the fluorescent material and a light of an unabsorbed first light passes through said the fluorescent material from said light emitting component are capable of overlapping each other to make white light;

wherein a resin containing distribution of the phosphor concentration is tapering the concentration with the distance from the light emitting component.

2. The light emitting device according to claim 1, wherein the concentration of phosphor increases from the surface of a resin wherein the phosphor is contained toward the light emitting component.

3. The light emitting device according to claim 1, wherein the concentration of phosphor increases from the light emitting component toward the surface of the resin.

4. The light emitting device according to any one of claims 1 to 3, wherein the distributions of the phosphor concentration are achieved at least by selecting or controlling the resin which contains the phosphor, forming temperature and viscosity, and the configuration and particle distribution of the phosphor.

8. The light emitting device according to any one of claims 1 and 5, wherein said a gallium nitride based semiconductor is a gallium nitride based semiconductor containing Indium.

9. The light emitting device according to any one of claims 1 and 5, wherein said fluorescent material is a garnet fluorescent material containing the rare earth element.

10. The light emitting device according to claim 9, wherein said fluorescent material is a garnet fluorescent material activated cerium.

11. The light emitting device according to claim 10, wherein said phosphor is a garnet fluorescent material comprising Y and Al and activated with at least cerium.

12. The light emitting device according to claim 11, wherein the fluorescent material is YAG:

Ce.

13. The light emitting device according to claim 12, wherein said YAG:

Ce contain Gd.

5. A light emitting device which comprises a light emitting component having a gallium nitride based semiconductor and a resin containing a phosphor capable of absorbing a part of a first light of blue color emitting from the light emitting component and emitting a second light of wavelength different from that of the absorbed first light, said emission of the second light emitted from the fluorescent material and a light of an unabsorbed first light passes through said fluorescent material from said light emitting component are capable of overlapping each other to make white light;

wherein the two or more kinds of fluorescent materials are independently arranged wherein fluorescent material that absorbs light from the light emitting component of a shorter wavelength is near the light emitting component, and a fluorescent material that absorbs light of a longer wavelength is away from the light emitting component.

6. The light emitting device according to claim 5, wherein the concentration of phosphor is controlled.

7. The light emitting device according to claim 6, wherein the distributions of the phosphor concentration be achieved at least by selecting or controlling the resin which contains the phosphor, forming temperature and viscosity, and the configuration and particle distribution of the phosphor.

14. A light emitting device which comprises a light emitting component having a gallium nitride based semiconductor and a resin containing a phosphor capable of absorbing a part of a first light of blue color emitting from the light emitting component and emitting a second light of wavelength different from that of the absorbed first light, said emission of the second light emitted from the fluorescent material and a light of an unabsorbed first light passes through said the fluorescent material from said light emitting component are capable of overlapping each other to make white light;

wherein the spectrum of said gallium nitride based semiconductor is a peak wavelength within the range from 420 to 490 nm,

the spectrum of said fluorescent material is a peak wavelength existing around the range from 530 to 570 nm,

and said fluorescent material has a controlled particle size distribution.

15. The light emitting device according to claim 14, wherein the emission color of the light emitting device is made constant using a fluorescent material having a relatively short emission wavelength for a light emitting component of a relatively short emission wavelength and using a fluorescent material having a relatively long emission wavelength for a light emitting component of a relatively long emission wavelength.

16. The light emitting device according to any one of claims 14 to 15, wherein the color of light emitted by the white light emitting device corresponds to a point on a straight line connecting a point of chromaticity generated by said gallium nitride base semiconductor and a point of chromaticity generated by the fluorescent material is substantially along the black body radiation locus.