Fluoride fluorescent material and light emitting device

Patent metadata

Field	Value
Publication number	US-10400166-B2
Application number	US-201815910735-A
Country	US
Kind code	B2
Filing date	Mar 2, 2018
Priority date	Sep 30, 2014
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

A method for producing a fluoride fluorescent material including: preparing a first solution containing manganese, a second solution containing at least one cation selected from the group consisting of K+, Li+, Na+, Rb+, Cs+, and NH4+, and a third solution containing at least one element selected from the group consisting of the elements from Groups 4 and 14 of the periodic table, and adding the first and third solutions dropwise, each at a rate of 0.3% or less of the total volume of the solution per minute to the second solution to obtain particles having a composition represented by formula (I): A2[M1−aMn4+aF6] (I) wherein A denotes at least one cation selected from the group consisting of K+, Li+, Na+, Rb+, Cs+, and NH4+; M denotes at least one element selected from the group consisting of the elements from Groups 4 and 14 of the periodic table; and a satisfies 0.04<a<0.20.

First claim

What is claimed is:

1. A fluoride fluorescent material comprising particles having a composition represented by formula (I):
A 2 [M 1−α Mn 4+ a F 6 ]  (I)

wherein
A denotes at least one cation selected from the group consisting of K + , Li + , Na + , Rb + , Cs + , and NH 4 + ;
M denotes at least one element selected from the group consisting of elements from Groups 4 and 14 of the periodic table; and
a satisfies 0.01<a<0.20,
the fluoride fluorescent material having an IR spectral area ratio, Z 1 , which is obtained by formula (P), of less than 2.0×10 −3 in an infra-red absorption spectrum
Z 1 =(spectral area from 3500 cm −1 to 3800 cm −1 )/(spectral area from 1050 cm −1 to 1350 cm −1 ) (P).

2. The fluoride fluorescent material according to claim 1 , wherein the IR spectral area ratio, Z 1 , is less than 1.0×10 −3 .

3. The fluoride fluorescent material according to claim 1 , wherein the IR spectral area ratio, Z 1 , is 1.0×10 −5 or more.

4. The fluoride fluorescent material according to claim 1 , wherein A contains K + and M contains Si.

5. The fluoride fluorescent material according to claim 1 , wherein an internal fluorescence quantum efficiency is 80% or more.

6. A light emitting device comprising:
a light source that emits light in a wavelength range of from 380 nm to 485 nm;
a first fluorescent material comprising the fluoride fluorescent material according to claim 1 ; and
a second fluorescent material that absorbs light in a wavelength range of from 380 nm to 485 nm and has a maximum emission wavelength in a wavelength range of from 495 nm to 590 nm.

7. The light emitting device according to claim 6 , wherein the second fluorescent material is at least one selected from the group consisting of: β sialon fluorescent materials; halo-silicate fluorescent materials; silicate fluorescent materials; rare-earth aluminate fluorescent materials; and sulfide fluorescent materials.

8. The light emitting device according to claim 7 , wherein the β sialon fluorescent materials have a composition represented by formula (IIa); the halo-silicate fluorescent materials have a composition represented by formula (IIb); the silicate fluorescent materials have a composition represented by formula (IIc); the rare-earth aluminate fluorescent materials have a composition represented by formula (IId); or the sulfide fluorescent materials have a composition represented by formula (IIe)
Si 6−t Al t O t N 8−t :Eu  (IIa)

wherein t satisfies 0<t≤4.2
(Ca,Sr,Ba) 8 MgSi 4 O 16 (F,Cl,Br) 2 :Eu  (IIb)

(Ba,Sr,Ca,Mg) 2 SiO 4 :Eu  (IIc)

(Y,Lu,Gd,Tb) 3 (Al,Ga) 5 O 12 :Ce  (IId)

(Ba,Sr,Ca)Ga 2 S 4 :Eu  (IIe).

9. The light emitting device according to claim 6 , having a correlated color temperature (CCT) of less than 4000 K.

10. The light emitting device according to claim 6 , wherein the mass ratio of the second fluorescent material to the first fluorescent material is from 5:95 to 95:5.

Assignees

• Nichia Corp

Inventors

• Yoshida Tomokazu
• Hosokawa Shoji
• Wakui Sadakazu
• Okazaki Toshiyuki

Classifications

• H10W90/756

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

• H10W90/736

  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

• C09K11/617 Primary

  Silicates · CPC title