Red Nitride Phosphor and Production Method Thereof

• US 20080128726A1
• Filed: 01/25/2006
• Published: 06/05/2008
• Est. Priority Date: 01/31/2005
• Status: Active Grant

• Current Assignee: UBE Industries Limited
• Original Assignee: UBE Industries Limited
• Inventors: Yamada, Tetsuo, Yamao, Takeshi, Sakata, Shin-ichi
• Granted Patent: US 8,148,886 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: C01B 21/0602 with two or more other elements chosen from metals, silicon or boron
• CPC Class Codes: C01P 2002/54 one element only
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/77 by unit-cell parameters, atom positions or structure diagrams
• CPC Class Codes: C01P 2002/84 by UV- or VIS- data
• CPC Class Codes: C01P 2006/60 Optical properties, e.g. expressed in CIELAB-values
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7728 containing europium

Abstract

A red phosphor where the crystal phase constituting the phosphor is monoclinic Eu-activated CaAlSiN₃. A red phosphor which is Eu-activated CaAlSiN₃ powder having an average particle diameter of 10 μm or less as measured in the non-pulverized state by the laser scattering particle size distribution analysis. A light-emitting device comprising a blue light-emitting element, a yellow phosphor capable of converting the blue light emitted from the blue light-emitting element into yellow light, and the above-described red phosphor capable of converting the blue light emitted from the blue light-emitting element into red light. A method for producing Eu-activated CaAlSiN₃, comprising firing a raw material powder comprising Ca₃N₂, AlN, Si₃N₄ and EuN at 1,400 to 2,000° C. in a nitrogen-containing atmosphere, the Ca₃N₂, AlN and Si₃N₄ giving a composition falling in the region surrounded by a straight line connecting the following four points A to D in the composition diagram of FIG. 1 and EuN being contained in an amount of 0.01 to 10 parts by weight as Eu per 100 parts by weight in total of Ca₃N₂, AlN and Si₃N₄.

Claims

1. A red phosphor characterized in that the crystal phase constituting the phosphor is monoclinic Eu-activated CaAlSiN₃.

2. The red phosphor as claimed in claim 1, which contains from 0.01 to 10 parts by weight of Eu per 100 parts by weight of the CaAlSiN₃ crystal phase.

3. The red phosphor as claimed in claim 1 or 2, which does not contain free AlN.

4. The red phosphor as claimed in claim 3, wherein AlN is not detected by the X-ray diffraction analysis.

22. A method for producing a light-emitting device, comprising combining the red phosphor claimed in claim 1 or 5, a yellow phosphor and a light-emitting element.

5. A red phosphor which is Eu-activated CaAlSiN₃ powder having an average particle diameter of 10 μ

m or less as measured in the non-pulverized state by the laser scattering particle size distribution analysis.

6. A red phosphor which is a pulverized product of the Eu-activated CaAlSiN₃ powder claimed in claim 5.

7. The red phosphor as claimed in claim 5 or 6, which is a monoclinic crystal.

10. A light-emitting device comprising a light-emitting element, a yellow phosphor, and the red phosphor claimed in claim 5.

11. The light-emitting device as claimed in claim 10, wherein the light-emitting element is a blue light-emitting diode.

12. The light-emitting apparatus as claimed in claim 11, wherein said red phosphor converts the blue light emitted from said blue light-emitting element into red light.

8. Monoclinic partially Eu-substituted CaAlSiN₃.

9. Monoclinic CaAlSiN₃.

13. A method for producing monoclinic Eu-activated CaAlSiN₃, comprising firing a raw material powder comprising Ca₃N₂, AlN, Si₃N₄ and EuN at about 1,400 to about 2,000°

C. in a nitrogen-containing atmosphere, the Ca₃N₂, AlN and Si₃N₄ giving a composition falling in the region surrounded by straight lines connecting the following four points A to D in the composition diagram of FIG. 1, that is, the four points defined by the following molar ratios of (Ca₃N₂;

AlN;

Si₃N₄);

Point A;

(10;

70;

20)

Point B;

(10;

65;

25)

Point C;

(70;

23;

7)

Point D;

(70;

22;

8),

and EuN being contained in an amount of 0.01 to 10 parts by weight as Eu per 100 parts by weight in total of Ca₃N₂, AlN and Si₃N₄.

14. The method as claimed in claim 13, wherein the firing is preformed at about 1,600 to about 2,000°

C. in a pressurized nitrogen atmosphere.

15. The method as claimed in claim 13, wherein Ca₃N₂ occupies from about 20 to about 40 mol % in 100 mol % in total of Ca₃N₂, AlN and Si₃N₄ constituting the raw material powder.

16. The method as claimed in claim 13, wherein the molar ratio of AlN and Si₃N₄ in the raw material powder is about 3:

1.

17. The method as claimed in any claim 13, which uses a raw material powder comprising EuN partially substituted by Eu₂O₃.

18. The method as claimed in claim 13, wherein amorphous Si₃N₄ or a nitrogen-containing silane compound is used as the raw material Si₃N₄.

19. The method as claimed in claim 13, wherein the nitrogen-containing atmosphere is a nitrogen atmosphere.

20. The method as claimed in claim 13, wherein the monoclinic Eu-activated CaAlSiN₃ crystal after firing is further acid-cleaned to remove an oxide.

21. The method as claimed in claim 13, wherein the monoclinic Eu-activated CaAlSiN₃ is a red phosphor.