Light emitting device with blue light LED and phosphor components

• US 7,329,988 B2
• Filed: 01/16/2007
• Issued: 02/12/2008
• Est. Priority Date: 07/29/1996
• Status: Expired due to Fees

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Shimizu, Yoshinori, Moriguchi, Toshio, Sakano, Kensho, Noguchi, Yasunobu
• Primary Examiner(s): WILLIAMS, JOSEPH L
• Application Number:
  US11/653,275
• Publication Number:
  US 20070114914A1
• Time in Patent Office: 392 Days
• Field of Search: 313504-512, 313/498, 252/301.4 F, 252/301.6
• 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

A color converting molding material and a light emitting device having the color converting molding material are discussed. According to an embodiment, the color converting molding material, includes a resin or glass; and a phosphor for converting a visible light emitted from a light emitting semiconductor component having a GaN-base compound semiconductor as a light emitting layer to a complimentary light with the visible light wherein said phosphor includes two or more garnet fluorescent materials containing a rare earth element, the two or more garnet fluorescent materials being different from each other.

Claims

1. A color converting molding material comprising:

a resin or glass; and

a phosphor for converting a visible light emitted from a light emitting semiconductor component comprising a GaN-base compound semiconductor as a light emitting layer to a complimentary light with the visible light,

wherein said phosphor comprises two or more garnet fluorescent materials containing a rare earth element, the two or more garnet fluorescent materials being different from each other; and

said phosphor comprises a first and second garnet fluorescent materials, said garnet fluorescent materials comprising at least element Y, wherein a part of Y contained in said garnet fluorescent materials is replaced with Gd and the amounts of said replacement of Y with Gd in said first and second garnet fluorescent materials are different from each other.

2. The color converting molding material according to claim 1, wherein said two or more garnet fluorescent materials comprise at least one elements 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, said two or more garnet fluorescent materials being activated with Ce.

3. The color converting molding material according to claim 1, wherein said two or more garnet fluorescent materials are a fluorescent material having an Y-Al garnet system comprising Y and Al.

4. The color converting molding material according to claim 1, wherein said two or more garnet fluorescent materials are a fluorescent material represented by a general formula (Re_1-rSm_r)₃(Al_1-sGa_s)₅O₁₂:

Ce, wherein 0≦

r<

1, 0≦

s≦

1 and Re is at least one selected from Y and Gd.

5. The color converting molding material according to claim 1, wherein said phosphor contains a first garnet fluorescent material represented by a general formula Y₃(Al_1-sGa_s)₅O₁₂ and a second garnet fluorescent material represented by a general formula Re₃Al₅O₁₂:

Ce, wherein 0≦

s≦

1 and Re is at least one selected from Y, Gd and La.

6. The color converting molding material according to claim 1, wherein a particle size distribution of said phosphor is controlled.

7. The color converting molding material according to claim 1, wherein said resin is one selected from the group consisting of epoxy resin, urea resin and silicone resin.

8. The color converting molding material according to claim 1, wherein said resin contains at least one selected from the group consisting of dispersing material, pigment and ultraviolet light absorbing material.

9. The color converting molding material according to claim 1, wherein said resin contains at least one selected from the group consisting of barium titanate, titanium oxide, aluminum oxide and silicon oxide.

10. The color converting molding material according to claim 1, wherein a main peak wavelength of the emission spectrum of said light emitting semiconductor component is not smaller than 400 nm and not larger than 530 nm, and the main emission wavelength of said phosphor is larger than said main peak wavelength of the emitting spectrum of said light emitting semiconductor component.

11. The color converting molding material according to claim 1, wherein said light emitting layer of said light emitting semiconductor component has a single quantum well or multiple quantum well structure.

12. The color converting molding material according to claim 1, wherein said light emitting layer of said light emitting semiconductor component comprises a gallium-nitride semiconductor compound containing In.

13. The color converting molding material according to claim 1, wherein said two or more garnet fluorescent materials are arranged separately.

14. The color converting molding material according to claim 1, wherein said two or more garnet fluorescent materials are arranged in layers.

15. The color converting molding material according to claim 1, wherein the amounts of said two or more garnet fluorescent materials are controlled to modify the colour of said complimentary light.

16. The color converting molding material according to claim 1, wherein said two or more garnet fluorescent materials are arranged separately, and a first garnet fluorescent material absorbing said visible light at the side of a shorter wavelength of the visible light is provided at a closer position to said light emitting semiconductor component than a second garnet fluorescent material.

17. The color convening molding material according to claim 1, wherein said resin or glass is transparent.

18. A light emitting device emitting a white light having the color converting molding material according to claim 1, wherein the main peak of said light emitting semiconductor component is within the range of 420 to 490 nm and the main emitting wavelength of the phosphor is selected to be larger than said main peak of the spectrum of said light emitting semiconductor component.

19. The light emitting device according to claim 18, wherein the main peak of said light emitting semiconductor component is within the range of 450 to 475 nm.

20. The light emitting device according to claim 18, wherein said light emitting device has good color rendering.

21. The light emitting device according to claim 18, wherein the distribution of the phosphor concentration is controlled according to the distance from said semiconductor light emitting component.

22. The light emitting device according to claim 21, wherein the concentration of said phosphor decreases according to the distance from said semiconductor light emitting component.

23. The light emitting device according to claim 21, wherein the concentration of said phosphor increases according to the distance from said semiconductor light emitting component.

24. The light emitting device according to claim 21, wherein the distribution of the phosphor concentration is controlled by selecting or controlling the material which contains the phosphor, forming temperature and viscosity, and the configuration and particle size distribution of the phosphor.

25. A color converting molding material comprising:

a resin or glass; and

a phosphor for converting a visible light emitted from a light emitting semiconductor component comprising a GaN-base compound semiconductor as a light emitting layer to a complimentary light with the visible light;

wherein said phosphor comprises two or more garnet fluorescent materials containing a rare earth element the two or more garnet fluorescent materials being different from each other;

said two or more garnet fluorescent materials are a fluorescent material represented by a general formula (Re_1-rSm_r)₃(Al_1-sGa_s)₅O₁₂;

Ce, wherein 0≦

r<

1, 0≦

s≦

1 and Re is at least one selected from Y and Gd; and

wherein said two or more garnet fluorescent materials are a fluorescent material represented by a general formula (Y_1-p-q-rGd_pCe_qSm_r)₃(Al_1-sGa_s)₅O₁₂, wherein 0≦

p<

0.8, 0.003≦

q≦

0.2, 0.0003≦

r≦

0.08 and 0≦

s≦

1.