Process for producing fluorescent material

Patent metadata

Field	Value
Publication number	US-10759995-B2
Application number	US-201615551860-A
Country	US
Kind code	B2
Filing date	Feb 17, 2016
Priority date	Feb 18, 2015
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

The present invention relates to a process for producing a composite-fluoride fluorescent material represented by the general formula A2MF6:Mn4+ (wherein A is at least one alkali metal element including K; M is one or more metallic elements including at least Si or Ge and selected from among Si, Ge, Sn, Ti, Zr, and Hf; F is fluorine; and Mn is manganese). With the production process, it is possible to obtain a fluorescent material which is high in absorptance, internal quantum efficiency, and external quantum efficiency and has excellent optical properties.

First claim

The invention claimed is:

1. A method for producing a phosphor represented by the general formula A 2 MF 6 :Mn 4 +(where the element A is an alkali metal element including at least K; the element M is one or more metal elements chosen from among Si, Ge, Sn, Ti, Zr and Hf, including at least Si or Ge; F is fluorine, and Mn is manganese); the method for producing a phosphor comprising:
a dissolution step of dissolving raw materials containing the element A, the element M, F and Mn in a solvent comprising hydrofluoric acid; and
a precipitation step of precipitating the phosphor from a solution obtained in the dissolution step; wherein
the amounts of the raw materials added during the dissolution step are controlled so as to keep the phosphor at a saturated dissolution level or lower; and
the precipitation step is performed by lowering a hydrogen fluoride concentration in the solution by adding water or low-concentration hydrofluoric acid.

2. The production method according to claim 1 , wherein a hydrogen fluoride concentration in the hydrofluoric acid used in the dissolution step is 40-70 mass %.

3. The production method according to claim 1 , wherein the hydrogen fluoride concentration in the solution is lowered to be within a range of 5 to 40 mass % by dilution with water or low-concentration hydrofluoric acid.

4. The production method according to claim 1 , wherein the precipitation step further comprises cooling the solution to within a range of −35 to 20° C.

5. The production method according to claim 1 , wherein the element A is potassium and the element M is silicon.

Assignees

• Denka Company Ltd

Inventors

• Ichikawa Masayoshi
• Kondo Ryosuke
• Emoto Hideyuki
• Tanaka Motoi

Classifications

• C01G45/22

  Compounds containing manganese, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• C09K11/665

  with alkali or alkaline earth metals · CPC title

• C09K11/617

  Silicates · CPC title

• C09K11/613 Primary

  with alkali or alkakine earth metals · CPC title

• C01B33/10

  Compounds containing silicon, fluorine, and other elements · CPC title