Sialon-based phosphor and its production method

• US 20050012075A1
• Filed: 07/16/2004
• Published: 01/20/2005
• Est. Priority Date: 07/16/2003
• Status: Active Grant

• Current Assignee: Denka Company Limited
• Original Assignee: UBE Industries Limited
• Inventors: Sakata, Shin-ichi, Yamada, Tetsuo
• Granted Patent: US 7,144,524 B2
• Time in Patent Office: Days
• US Class Current: 252/301.40F
• CPC Class Codes: C04B 2235/3203 Lithium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/3873 Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
• CPC Class Codes: C04B 2235/44 Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
• CPC Class Codes: C04B 2235/442 Carbonates
• CPC Class Codes: C04B 2235/766 Trigonal symmetry, e.g. alpha-Si3N4 or alpha-Sialon
• CPC Class Codes: C04B 35/597 based on silicon oxynitride, e.g. SIALONS
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/77498 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2924/181 : Encapsulation
• CPC Class Codes: H01L 33/502 : Wavelength conversion materials

Abstract

To provide a Sialon-based phosphor having a high photoluminescent intensity, which can realize a high brightness LED, particularly a white LED using a blue LED as the light source, and a production method of the Sialon-based phosphor. The α-Sialon based phosphor of the present invention is represented by the formula:
Li_xM_yLn_zSi_12−(m+n)Al_(m+n)O_nN_16−n   (I) wherein M is at least one metal selected from Ca, Mg and Y, Ln is at least one lanthanide metal selected from Eu, Dy, Er, Tb, Yb and Ce, x+ay+bz=m (assuming that the valence of metal M is a and the valence of lanthanide metal Ln is b), 0<x≦0.8, 0<y, 0<z, 0.3≦m<4.5, and 0<n<2.25.

Claims

1. An α

-Sialon based phosphor represented by the formula;

Li_xM_yLn_zSi<sub>12−

(m+n)</sub>Al_(m+n)O_nN<sub>16−

n</sub>  

 

(I)

wherein M is at least one metal selected from Ca, Mg and Y, Ln is at least one lanthanide metal selected from Eu, Dy, Er, Tb, Yb and Ce, x+ay+bz=m (assuming that the valence of metal M is a and the valence of lanthanide metal Ln is b), 0<

x≦

0.8, 0<

y≦

1.5, 0<

z≦

1.5, 0.3≦

m<

4.5, and 0<

n<

2.25.

2. The α

-Sialon based phosphor as claimed in claim 1, wherein the metal M is Ca and the lanthanide metal Ln is Eu.

3. The α

-Sialon based phosphor as claimed in claim 1, wherein x is 0.01<

x≦

0.3.

4. The α

-Sialon based phosphor as claimed in claim 3, wherein x is 0.03<

x≦

0.2.

5. The α

-Sialon based phosphor as claimed in claim 1, wherein 1.0≦

m≦

3.5 and 0.5≦

n≦

2.0.

6. A method for producing the α

-Sialon based phosphor claimed in any one of claims 1 to 5, comprising;

mixing an oxide of Li, or a precursor substance working out to the oxide, upon thermal decomposition, an amorphous silicon nitride, an aluminum compound containing AlN, and working out to an aluminum source, an oxide of said metal M, or a precursor substance working out to the oxide upon thermal decomposition, and an oxide of the lanthanide metal Ln, or a precursor substance working out to the oxide upon thermal decomposition, and

firing the resulting powder mixture at 1,400 to 2,000°

C. in an inert gas atmosphere containing nitrogen.

7. The method for producing the α

-Sialon based phosphor as claimed in claim 6, wherein said amorphous silicon nitride is an amorphous silicon nitride powder obtained by the thermal decomposition of silicon diimide (Si(NH)₂).

8. The method for producing the α

-Sialon based phosphor as claimed in claim 6, wherein said firing is performed at 1,600 to 2,000°

C. in a pressurized nitrogen gas atmosphere.

9. A light emitting diode apparatus comprising a light emitting diode and the α

-Sialon based phosphor claimed in any one of claims 1 to 5.

10. A white light emitting diode apparatus comprising a blue or violet light emitting diode and the α

-Sialon based phosphor claimed in any one of claims 1 to 5.

11. The white light emitting diode apparatus as claimed in claim 10, wherein in said α

-sialon phosphor, the metal M is Ca and the lanthanide Ln is Eu.

12. The light emitting diode apparatus as claimed in claim 9, wherein the α

-Sialon based phosphor is dispersed in a resin.

13. The light emitting diode apparatus as claimed in claim 10, wherein the α

-Sialon based phosphor is dispersed in a resin.