Red nitride phosphor and production method thereof

• US 8,148,886 B2
• Filed: 01/25/2006
• Issued: 04/03/2012
• Est. Priority Date: 01/31/2005
• Status: Active Grant

• Current Assignee: UBE Industries Limited
• Original Assignee: UBE Industries Limited
• Inventors: Sakata, Shin-ichi, Yamao, Takeshi, Yamada, Tetsuo
• Primary Examiner(s): Williams, Joseph L
• Assistant Examiner(s): LEE, NATHANIEL J.
• Application Number:
  US11/795,298
• Publication Number:
  US 20080128726A1
• Time in Patent Office: 2,260 Days
• Field of Search: 313/486, 252/301.4 F
• US Class Current: 313/486
• 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 method for producing Eu-activated CaAlSiN₃ powder, comprising firing a mixture of Ca₃N₂, AlN, Si₃N₄ and EuN raw material powder at 1,400 to 2,000°

C. in a nitrogen-containing atmosphere, the Ca₃N₂, AlN and Si₃N₄ raw material powders giving a composition represented by xCa₃N₂.yAlN.zSi₃N₄, wherein x+y+z=100, 10≦

x≦

70 and y;

z=(72;

28) to (78;

22), and the EuN being contained in an amount of 0.01 to 10 parts by weight as Eu per 100 parts by weight in total of the Ca₃N₂, AlN and Si₃N₄, wherein an amorphous Si₃N₄ or a nitrogen-containing silane compound is used as the Si₃N₄ raw material powder.

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

m or less as measured in the non-pulverized state by laser scattering particle size distribution analysis and which is obtained by the method according to claim 1.

3. A light-emitting device comprising a light-emitting element, a yellow phosphor, and the red phosphor claimed in claim 2.

4. The light-emitting device as claimed in claim 3, wherein the light-emitting element is a blue light-emitting diode.

5. The light-emitting apparatus as claimed in claim 4, wherein said red phosphor converts the blue light emitted from said blue light-emitting element into red light.

6. The method as claimed in claim 1, wherein the firing is performed at 1,600 to 2,000°

C. in a pressurized nitrogen atmosphere.

7. The method as claimed in claim 1, wherein Ca₃N₂ occupies from 20 to 40 mol % in 100 mol % in total of the Ca₃N₂, AlN and Si₃N₄.

8. The method as claimed in claim 1, wherein the molar ratio of AlN and Si₃N₄ is about 3:

1.

9. The method as claimed in claim 1, which uses a raw material powder comprising EuN partially substituted by Eu₂O₃.

10. The method as claimed in claim 1, wherein the nitrogen-containing atmosphere is a nitrogen atmosphere.

11. The method as claimed in claim 1, wherein the Eu-activated CaAlSiN₃ crystal after firing is further acid-cleaned to remove an oxide covering the Eu-activated CaAlSiN₃ crystal powder.

12. The method as claimed in claim 1, wherein the Eu-activated CaAlSiN₃ is a red phosphor.

13. The method as claimed in claim 1, wherein amorphous Si₃N₄ is used as the Si₃N₄ raw material powder.