Stable red ceramic phosphors and technologies including the same

Patent metadata

Field	Value
Publication number	US-10964853-B2
Application number	US-201615762126-A
Country	US
Kind code	B2
Filing date	Sep 19, 2016
Priority date	Sep 24, 2015
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

Wavelength converters including coarse particles/grains of a red nitride phosphor are disclosed. In some embodiments the red nitride phosphor is a (Ca,Sr,Ba)2Si5N8:Eu phosphor with a D50 grain size or a D50 particle size that is ≥5 microns. The red nitride phosphor may be encapsulated within an organic matrix or present in an inorganic matrix. In the latter case, the inorganic matrix may include fine grains with a D50 grain size <5 microns. Methods of making such wavelength converters and devices including such wavelength converters are also described.

First claim

What is claimed is:

1. A wavelength converter, comprising:
a matrix; and
a wavelength conversion material within the matrix;

wherein:
the wavelength conversion material comprises a (Ca x Sr y Ba z ) 2 Si 5 N 8 :d % Eu phosphor, wherein d is the amount of Eu in atomic percent, and the following relationships are met:
0.03< x≤ 0.07;
0.4< y≤ 0.5;
0< z< 1;
x+y+z= 1; and
1.5≤ d≤ 5; and

said (Ca x Sr y Ba z ) 2 Si 5 N 8 :d % Eu phosphor has a D50 grain size greater than or equal to 5 microns; and wherein said matrix is an inorganic matrix selected from the group consisting of optically transparent metal nitrides, metal oxynitrides, metal activated silicon nitride phosphors where a concentration of metal activator is greater than 0 but less than 2 atomic %, and silicon nitrides having the formula (Ca x Sr y Ba z ) 2 Si 5 N 8 where x, y, and z have the same relationship as mentioned with respect to the phosphor; wherein said inorganic matrix has a D50 grain size <5 μm.

2. The wavelength converter of claim 1 , wherein said (Ca x Sr y Ba z ) 2 Si 5 N 8 :d % Eu phosphor has a D50 grain size greater than or equal to 10 microns.

3. The wavelength converter of claim 1 , wherein said (Ca x Sr y Ba z ) 2 Si 5 N 8 :d % Eu phosphor has a D50 grain size ≥15 microns.

4. The wavelength converter of claim 1 , wherein said inorganic matrix has a D50 grain size <1 μm.

5. The wavelength converter of claim 1 , wherein said inorganic matrix is selected from the group consisting of aluminum nitride, Ca—SiAlON, an (Sr, Ba) 2 Si 5 N 8 :Eu phosphor where the concentration of Eu is greater than 0 but less than 2 atomic %, and (Ca x Sr y Ba z ) 2 Si 5 N 8 .

6. The wavelength converter of claim 5 , wherein said inorganic matrix is an (Ca x Sr y Ba z ) 2 Si 5 N 8 , and a ratio of Ca, Sr, and Ba in (Ca x Sr y Ba z ) 2 Si 5 N 8 is the same or substantially the same as a ratio of Ca, Sr, and Ba in said (Ca x Sr y Ba z ) 2 Si 5 N 8 :d % Eu phosphor.

7. The wavelength converter of claim 1 , wherein said phosphor has a D50 grain size ≥15 μm.

8. A lighting device comprising the wavelength converter of claim 1 .

Assignees

• Osram Opto Semiconductors Gmbh
• Osram Oled Gmbh

Inventors

• Zheng Yi
• Tragl Sonja
• Kechele Juliane
• Strube-Knyrim Johanna
• Raukas Madis
• Lange Stefan
• Bichler Daniel

Classifications

• C09K11/77347

  Silicon Nitrides or Silicon Oxynitrides · CPC title

• H10H20/8512 Primary

  Wavelength conversion materials · CPC title

• C09K11/0883

  Arsenides; Nitrides; Phosphides · CPC title

• C09K11/025

  non-luminescent particle coatings or suspension media · CPC title

• C09K11/7734

  Aluminates · CPC title