SIALON PHOSPHOR, PROCESS FOR PRODUCING THE SAME, AND ILLUMINATOR AND LUMINESCENT ELEMENT EMPLOYING THE SAME

• US 20100237767A1
• Filed: 05/08/2007
• Published: 09/23/2010
• Est. Priority Date: 05/10/2006
• Status: Abandoned Application

• Current Assignee: Denki Kagaku Kogyo Kabushiki Kaisha (TDK Corporation)
• Original Assignee: Denki Kagaku Kogyo Kabushiki Kaisha (TDK Corporation)
• Inventors: Kawasaki, Takashi, Ibukiyama, Masahiro, Emoto, Hideyuki
• Application Number:
  US12/300,127
• Publication Number:
  US 20100237767A1
• Time in Patent Office: Days
• US Class Current: 313/503
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• 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 2235/442 Carbonates
• CPC Class Codes: C04B 2235/445 Fluoride containing anions, e.g. fluosilicate
• CPC Class Codes: C04B 2235/5409 expressed by specific surface values
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/761 Unit-cell parameters, e.g. lattice constants
• CPC Class Codes: C04B 2235/766 Trigonal symmetry, e.g. alpha-Si3N4 or alpha-Sialon
• CPC Class Codes: C04B 2235/767 Hexagonal symmetry, e.g. beta-Si3N4, beta-Sialon, alpha-SiC or hexa-ferrites
• CPC Class Codes: C04B 35/597 based on silicon oxynitride, e.g. SIALONS
• CPC Class Codes: C04B 35/6262 of calcined, sintered clinker or ceramics
• CPC Class Codes: C09K 11/08 containing inorganic luminescent materials
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/646 Silicates
• CPC Class Codes: C09K 11/7731 with alkaline earth metals
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: Y10T 428/2982 : Particulate matter [e.g., sphere, flake, etc.]

Abstract

Phosphor that can provide white LED that uses a blue LED or an ultraviolet LED as a light source and that has superior luminous efficiency. This phosphor includes, as a main component, α-type sialon represented by a general expression: (M1)x(M2)y(Si,Al)₁₂(O,N)₁₆ (where M1 is one or more types of elements selected from a group consisting of Li, Mg, Ca, Y, and lanthanide element (except for La and Ce) and M2 is one or more types of elements selected from a group consisting of Ce, Pr, Eu, Tb, Yb, and Er, and 0.3≦X+Y≦1.5 and 0<Y≦0.7 are established and the sialon phosphor consists of a powder having a specific surface area of 0.2 to 0.5 m²/g.

Claims

1. A sialon phosphor that includes, as a main component, α

-type sialon represented by a general expression;

(M1)x(M2)y(Si,Al)₁₂(O,N)₁₆, wherein M1 is one or more types of elements selected from a group consisting of Li, Mg, Ca, Y, and lanthanide element (except for La and Ce) and M2 is one or more types of elements selected from a group consisting of Ce, Pr, Eu, Tb, Yb, and Er, and 0.3≦

X+Y≦

1.5 and 0<

Y≦

0.7 are established, and the sialon phosphor is a powder having a specific surface area of 0.2 to 0.5 m²/g,

said α

-type sialon has a lattice constant a in a range from 0.780 to 0.788 nm and a lattice constant c in a range from 0.565 to 0.573 nm, and

when powders consisting of said α

-type sialon are evaluated based on an X-ray diffraction method, crystal phases other than that of the α

-type sialon have diffraction intensities that are all 10% or less to a diffraction line intensity of a face (102) of the α

-type sialon.

4. The sialon phosphor according to claim 1, wherein the M1 includes at least Ca.

5. The sialon phosphor according to claim 1,

wherein the M2 includes at least Eu and 0<

Y≦

0.1 is established and, when ultraviolet light or visible light having wavelengths in a range from 250 to 500 nm is emitted as an excitation source to the sialon phosphor, the sialon phosphor shows a light emission characteristic having a peak in a wavelength range from 540 to 600 nm.

10. An illuminator consists of the sialon phosphor according to any of claims 1, 4, and 5 and a light-emitting light source emitting light having a predetermined wavelength.

11. The illuminator according to claim 10,

wherein the light has a wavelength in a range from 250 to 500 nm.

2. (canceled)

3. (canceled)

6. A method of manufacturing sialon phosphor that includes, as a main component, α

-type sialon represented by a general expression;

(M1)x(M2)y(Si,Al)₁₂(O,N)₁₆, wherein M1 is one or more types of elements selected from a group consisting of Li, Mg, Ca, Y, and lanthanide metal (except for La and Ce) and M2 is one or more types of elements selected from a group consisting of Ce, Pr, Eu, Tb, Yb, and Er, and 0.3≦

X+Y≦

1.5 and 0<

Y≦

0.7 are established,

wherein starting raw material is filled in a crucible made of boron nitride material having a density 1.75 g/cm³ or higher and burned in nitrogenous atmosphere.

7. The method of manufacturing sialon phosphor according to claim 6,

wherein starting raw material includes α

-type sialon in an amount of 5 to 30 mass %.

8. The method of manufacturing sialon phosphor according to claim 7,

wherein the starting raw material includes the α

-type sialon having a specific surface area in a range from 0.5 to 2 m²/g.

9. The method of manufacturing sialon phosphor according to claim 6,

wherein the crucible consists of pyrolytic boron nitride.

12. An illuminator consisting of phosphor obtained by the method of manufacturing sialon phosphor according to any of claims 6 to 9 and light-emitting light source emitting light having a predetermined wavelength.

13. The illuminator according to claim 12,

wherein the light has a wavelength in a range from 250 to 500 nm.

14. A sialon phosphor, wherein the phosphor is α

-type sialon represented by a general expression;

(M1)_X(M2)_Y(Si)_12-(m+n)(Al)_m+n(O)_n(N)_16-n, wherein M1 is one or more types of elements selected from a group consisting of Li, Mg, Ca, Sr, Y, and lanthanide metal (except for La and Ce) and M2 is one or more types of elements selected from Ce, Pr, Eu, Tb, Yb, and Er, and 0.3≦

X+Y≦

1.5, 0<

Y≦

0.7, 0.6≦

m≦

3.0, 0≦

n≦

2.5, X+Y=m/(average valence of M1 and M2),

the constituent particles of said phosphor have an average circularity degree of 0.75 or more, the phosphor has a particle size distribution D₅₀ of 5 to 30 μ

m and D₁₀ of 2.0 μ

m or more,

the particles of said phosphor includes light emission-related elements that have a low concentration in the interior of the particle and that have a high concentration at the outer periphery of the particle, and

the light emission-related element at the outer periphery of the phosphor particle has a concentration 1.2 times or more higher than that of the light emission-related element at the interior of the particle.

18. The sialon phosphor according to claim 14,

wherein the M1 is Ca and the M2 is Eu.

25. A luminescent element, comprising, as constituting elements:

the sialon phosphor according to any of claims 14, 18, 19, and 20; and

a light-emitting diode having the maximum intensity in light emission wavelengths in a range from 240 to 480 nm.

15. (canceled)

16. (canceled)

17. (canceled)

19. A sialon phosphor,

wherein the phosphor is composed of host material of β

-type sialon represented by a general expression of Si_6-zAl_zO_zN_8-z (wherein 0.01≦

z≦

4.2) and includes 0.01 to 10 atm % of a metal element M3, wherein M3 is one or more types of elements selected from among Mn, Ce, and Eu,

the constituent particles of said phosphor have an average circularity degree of 0.75 or more, a particle size distribution D₅₀ of 5 to 30 μ

m, and D₁₀ of 2.0 μ

m or more,

the particles of said phosphor includes light emission-related elements that have a low concentration in the interior of the particle and that have a high concentration at the outer periphery of the particle, and

the light emission-related element at the outer periphery of the phosphor particle has a concentration 1.2 times or more higher than that of the light emission-related element at the interior of the particle.

20. The sialon phosphor according to claim 19,

wherein 0.1≦

z≦

0.5 is established in the general expression and M3 is Eu and has a content from 0.03 to 0.3 atm %.

21. A method of manufacturing sialon phosphor, comprising:

a step of mixing silicon-containing material, aluminum-containing material, and raw material including M1 (one or more types of elements selected from a group consisting of Li, Mg, Ca, Sr, Y, and lanthanide metal (except for La and Ce)), M2 (one or more types of elements selected from Ce, Pr, Eu, Tb, Yb, and Er) to prepare granulated powders; and

a step of heating the powders in a nitrogen gas atmosphere at 1500 to 2100 degrees C. to obtain α

-type sialon phosphor,

said step of preparing granulated powder includes;

mixing said raw material, solvent, and a binder to prepare slurry,

recovering said slurry by a spray drier to make granulated powder, and

removing the binder from said recovered granulated powder.

22. The method of manufacturing sialon phosphor according to claim 21,

wherein previously-synthesized α

-type sialon phosphor is added to the raw material and mixed with the raw material.

26. The method of manufacturing sialon phosphor as set forth in claim 21, wherein

the particle diameter of said granulated powder is 10 to 35 μ

m.

23. A method of manufacturing sialon phosphor, comprising:

a step of mixing silicon-containing material, aluminum-containing material, and raw material including M3 (one or more types of elements selected from a group consisting of Mn, Ce, and Eu) to prepare granulated powders; and

a step of heating the powders in a nitrogen gas atmosphere at 1500 to 2100 degrees C. to obtain β

-type sialon phosphor,

said step of preparing granulated powder includes;

mixing said raw material, solvent, and a binder to prepare slurry,

recovering said slurry by a spray drier to make granulated powder, and

removing the binder from said recovered granulated powder.

24. The method of manufacturing sialon phosphor according to claim 23,

wherein previously-synthesized β

-type sialon phosphor is added to the raw material and mixed with the raw material.

27. The method of manufacturing sialon phosphor as set forth in claim 23, wherein the particle diameter of said granulated powder is 10 to 35 μ

m.