Method for producing phosphor

• US 9,850,131 B2
• Filed: 02/22/2013
• Issued: 12/26/2017
• Est. Priority Date: 10/09/2012
• Status: Active Grant

• Current Assignee: Denka Company Limited
• Original Assignee: Denka Company Limited
• Inventors: Nonogaki, Ryozo, Ichikawa, Masayoshi, Nomiyama, Tomohiro, Takeda, Yusuke
• Primary Examiner(s): Hoban, Matthew E
• Assistant Examiner(s): EDMONDSON, LYNNE RENEE
• Application Number:
  US14/434,162
• Publication Number:
  US 20150307353A1
• Time in Patent Office: 1,768 Days
• Field of Search: 2523014 F, 2523014 R, 264 21, 423326
• CPC Class Codes: C01B 21/0627 with one or more rare earth metals
• CPC Class Codes: C01B 21/082 Compounds containing nitrogen and non-metals and optionally metalsC01B21/06, C01B21/08 take precedence
• CPC Class Codes: C01B 21/0826 Silicon aluminium oxynitrides, i.e. sialons
• CPC Class Codes: C01P 2002/50 Solid solutions
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/84 by UV- or VIS- data
• CPC Class Codes: C09K 11/646 Silicates
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides

Abstract

Provided is a method for producing a phosphor, using a nitride raw material, that gives a high-reliability (Sr,Ca)AlSiN₃-based nitride phosphor at a productivity higher than before. The method comprises a mixing step of mixing raw materials and a calcining step of calcining the mixture obtained in the mixing step and, in producing the phosphor having a crystalline structure substantially identical with that of (Sr,Ca)AlSiN₃ crystal as the host crystal, a strontium nitride containing SrN, Sr₂N, or the mixture thereof as the main crystalline phase, as determined by crystalline phase analysis by powder X-ray diffractometry, and having a nitrogen content of 5 to 12 mass % is used as part of the raw materials.

Claims

1. A method for producing a phosphor, the host crystal thereof having a crystal structure substantially identical with that of (Sr,Ca)AlSiN₃ crystal, comprising:

a mixing step of mixing raw materials; and

a calcining step of calcining the mixture of the mixed raw materials under a temperature condition of 1500 to 1900°

C. in nitrogen atmosphere, wherein

the raw materials contain a strontium nitride powder,

the strontium nitride powder has a nitrogen content of 5 to 12 mass %, an oxygen content of 0.2 to 1 mass %, and a maximum diameter of 77 to 300 μ

m, and

the strontium nitride powder comprises SrN, Sr₂N, or the mixture thereof as determined by crystalline phase analysis by powder X-ray diffractometry.

2. The method for producing a phosphor according to claim 1, further comprising, before the mixing step, a classifying step of reducing the maximum diameter of the strontium nitride, part of the raw material, to 300 μ

m or less.

3. The method for producing a phosphor according to claim 1, wherein the raw materials, further comprise a calcium nitride powder, a silicon nitride powder, an aluminum nitride powder, and a europium compound powder.