Fluoride phosphor and light emitting device using the same and method of manufacturing the fluoride phosphor

Patent metadata

Field	Value
Publication number	US-9120972-B2
Application number	US-201414322872-A
Country	US
Kind code	B2
Filing date	Jul 2, 2014
Priority date	Jul 3, 2013
Publication date	Sep 1, 2015
Grant date	Sep 1, 2015

Abstract

A fluoride phosphor activated with tetravalent Mn can absorb blue light and emit red light, and is represented by the general formula: K 2 [M 1-a Mn 4+ a F 6 ] (M is at least one selected from group-IV elements of Ti, Zr, and Hf and group IVB elements of Si, Ge, Sn, and a is 0<a<0.2). The particles of the phosphor have a surface region where the concentration of tetravalent Mn is lower than the inner region of the phosphor particles.

First claim

What is claimed is:

1. A fluoride phosphor activated with tetravalent Mn having a general formula shown below and being in a form of particles, to absorb visible light of a short wavelength and emit red light, each phosphor particle having a surface region where a concentration of tetravalent Mn is lower than inner region of the phosphor particle
K 2 [M 1-a Mn 4+ a F 6 ]
(wherein M is at least one selected from group-IV elements of Ti, Zr, and Hf and group IVB elements of Si, Ge, Sn, and a is 0<a<0.2).

2. The fluoride phosphor according to claim 1 , wherein the concentration of tetravalent Mn is approximately uniform in the inner region of each phosphor particle, and is gradually decreased toward the surface in the surface region.

3. The fluoride phosphor according to claim 1 , wherein the concentration of tetravalent Mn in the surface region is 30% or less with respect to the concentration of tetravalent Mn in the inner region.

4. The fluoride phosphor according to claim 1 , wherein an elution amount of tetravalent Mn obtained by charging the fluoride phosphor in 1 to 5 times amount of pure water relative to the amount of the phosphor to dissolve surface of the phosphor particles is in a range of 0.05 to 3 ppm.

5. The fluoride phosphor according to claim 1 , wherein a luminous flux maintaining rate obtained by charging the fluoride phosphor in 1 to 5 times amount of pure water relative to the amount of the phosphor and left stand for one hour is 90% or greater.

6. The fluoride phosphor according to claim 1 , wherein M is Si or Si and Ge.

7. The fluoride phosphor according to claim 1 , wherein the thickness of the surface region is about 1/20 to about 1/50 of average particle diameter of the fluoride phosphor.

8. A light emitting device having the fluoride phosphor according to claim 1 , comprising a light source to emit light of visible light at a shorter wavelength side, and the fluoride phosphor to absorb the light and emit a red light.

9. The light emitting device according to claim 8 , wherein the light emitting device includes, in addition to the fluoride phosphor, at least one type of phosphor selected from (Ca, Sr, Ba) 2 SiO 4 :Eu, (Y,Gd) 3 (Ga,Al) 5 O 12 :Ce, (Si,Al) 6 (O,N) 8 :Eu, SrGa 2 S 4 :Eu, (Ca,Sr) 2 Si 5 N 8 :Eu, CaAlSiN 3 :Eu, and (Ca,Sr)AlSiN 3 :Eu.

10. The light emitting device according to claim 8 , wherein the light emitting device is used as backlight of liquid crystal.

Assignees

• Nichia Corp

Inventors

• Yoshida Tomokazu

Classifications

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W74/00

  Encapsulations, e.g. protective coatings · CPC title

• H10W72/884

  Die-attach connectors and bond wires · CPC title

• H10H20/853

  characterised by their shape · CPC title

• H10H20/8512

  Wavelength conversion materials · CPC title