Wavelength converting material for a light emitting device

Patent metadata

Field	Value
Publication number	US-10170670-B2
Application number	US-201815945106-A
Country	US
Kind code	B2
Filing date	Apr 4, 2018
Priority date	May 3, 2016
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

Embodiments of the invention include a wavelength-converting material defined by AE3−x1−y+zRE3−x2+y−z[Si9−wAlw(N1−yCy)[4](N16−z−wOz+w)[2]]:Eux1,Cex2, where AE=Ca, Sr, Ba; RE=Y, Lu, La, Sc; 0≤x1≤0.18; 0≤x2≤0.2; x1+x2>0; 0≤y≤1; 0≤z≤3; 0≤w≤3.

First claim

The invention claimed is:

1. A device comprising:
a wavelength converting material comprising:
a cubic crystal structure;
an Eu 2+ dopant;
cubic coordination of at least one Eu 2+ dopant site by X [2] (X═N, O) atoms;
star-shaped Y(SiX 4 ) 4 (Y═C, N) host lattice building blocks;
AE, where AE=Ca, Sr, Ba; and
RE, where RE=Y, Lu, La, Sc.

2. The device of claim 1 wherein an average effective ionic radii for AE+RE is no more than 120 pm.

3. The device of claim 1 wherein the wavelength converting material comprises AE 3−x1−y+z RE 3−x2+y−z [Si 9−w Al w (N 1−y C y ) [4] (N 16−z−w O z+w ) [2] ]:Eu x1 ,Ce x2 , where AE=Ca, Sr, Ba; RE=Y, Lu, La, Sc; 0≤x1≤0.18; 0≤x2≤0.2; x1+x2>0; 0≤y≤1; 0≤z≤3; 0≤w≤3.

4. The device of claim 1 further comprising a light emitting diode that emits blue light, wherein the wavelength converting material is disposed in a path of light emitted by the light emitting diode.

5. The device of claim 1 wherein the wavelength converting material is a first wavelength converting material that emits light having a peak wavelength that is red, the device further comprising a second wavelength converting material that emits light having a peak wavelength that is yellow or green.

6. The device of claim 1 wherein the wavelength converting material is formed into a ceramic.

7. The device of claim 6 , wherein the wavelength converting material has a density of at least 90% of a density of a single crystal of the wavelength converting material.

8. The device of claim 1 wherein the wavelength converting material is selected from the group consisting of Ca 2.49 La 0.5 Y 3 Si 9 N 16.5 C 0.5 :Eu 0.01 , Ca 2.985 Y 3 Si 8 AlON 16 :Eu 0.015 , Ca 2.985 Y 3 Si 9 N 17 :Eu 0.015 , Ca 1.985 La 4 Si 9 N 16 C:Eu 0.015 , Sr 1.985 Y 4 Si 9 N 16 C:Eu 0.015 , Sr 2.98 Sc 3 Si 9 N 17 : Eu 0.02 , Sr 2.98 Lu 3 Si 9 N 17 : Eu 0.02 , and Ca 5.97 Si 9 O 3 N 14 : Eu 0.03 .

9. The device of claim 1 wherein the wavelength converting material is Ca 3−x1−y RE 3+y Si 9 N 1−y C y N 16 :Eu x1 wherein 0.004<=x1<=0.09 and 0<y<=1.

10. A method comprising:
synthesizing a wavelength converting material comprising AE 3−x1−y+z RE 3−x2+y−z [Si 9−w Al w (N 1−y C y ) [4] (N 16−z−w O z+w ) [2] ]:EU x1 Ce x2 , where AE=Ca, Sr, Ba; RE=Y, Lu, La, Sc; 0≤x1≤0.18; 0≤x2≤0.2; x1+x2>0; 0≤y≤1; 0≤z≤3; 0≤w≤3, said synthesizing comprising:
providing a first precursor material comprising an alkaline earth element;
providing a second precursor material comprising a rare earth element;
providing a silicon source;
providing a dopant source;
mixing the first precursor material, the second precursor material, the silicon source, and the dopant source; and
firing the mixture.

11. The method of claim 10 wherein the first precursor material is selected from the group consisting of AE 3 N 2 and AEH 2 , where AE is an alkaline earth element.

12. The method of claim 10 wherein the second precursor material is selected from the group consisting of silicide RESi 2 , silicide Tris[N,N-bis(trimethylsilyl)amide]RE(III), nitride REN, mixed silicides crystallizing in the ThSi 2 structure type, and AE 1−x RE x Si 2 , where RE is a rare earth element.

13. The method of claim 10 wherein the silicon source is selected from the group consisting of Si 3 N 4 , perhydropolysilazane, silicon diimide, silicon, and silicon carbide.

14. The method of claim 10 wherein the dopant source is selected from the group consisting of Eu 2 O 3 , Eu 2 Si 5 N 8 , CeO 4 , CeF 3 , and Tris[N,N-bis(trimethylsilyl)amide]cerium.

15. The method of claim 10 wherein firing the mixture comprises:
forming an intermetallic precursor by a first firing under argon atmosphere;
processing the intermetallic precursor under a nitrogen or hydrogen-nitrogen mixture atmosphere to form a nitride phosphor material; and
increasing crystallinity of the nitride phosphor material by a second firing under an elevated nitrogen pressure.

16. The method of claim 10 , further comprising providing one or more fluxes, and providing one or more scattering materials.

Assignees

• Lumileds Holding Bv

Inventors

• Schmidt Peter

Classifications

• C09K11/7783

  containing two or more rare earth metals one of which being europium · CPC title

• C09K11/7766

  containing two or more rare earth metals · CPC title

• H01L33/504 Primary

  Electricity · mapped topic

• C09K11/7734

  Aluminates · CPC title

• C09K11/7728

  containing europium · CPC title