Method of manufacturing phosphor translucent ceramics and light emitting devices
Disclosed herein is a method of increasing the luminescence efficiency of a translucent phosphor ceramic. Other embodiments are methods of manufacturing a phosphor translucent ceramic having increased luminescence. Another embodiment is a light emitting device comprising a phosphor translucent ceramic made by one of these methods.
1. A method of increasing the luminescence efficiency of a translucent phosphor ceramic, comprising:
heating the translucent phosphor ceramic at a temperature in the range of about 1200° C. to about 1800° C. for a time period in the range of about 0.5 hours to about 20 hours under a reducing atmosphere, wherein said heating the translucent phosphor ceramic increases the luminescence efficiency, and wherein said phosphor translucent ceramic comprises a rare earth doped phosphor material having a garnet structure.
2. The method of claim 1 , wherein the temperature is lower than the melting point of the translucent phosphor ceramic.
3. The method of claim 1 , wherein the temperature is from about 1200° C. to about 1600° C.
4. The method of claim 1 , wherein the heating is for a time period in the range of about 3 to about 20 hours.
5. The method of claim 1 , wherein the reducing atmosphere comprises hydrogen gas.
6. The method of claim 5 , wherein the reducing atmosphere comprises a mixture of from about 1% (v/v) to about 10% (v/v) hydrogen gas and about 90% (v/v) to about 99% (v/v) nitrogen gas.
7. The method of claim 1 , wherein the translucent phosphor ceramic is prepared by a process comprising heating at least part of a plurality of particles at a temperature of from about 1450° C. to about 2000° C. under a vacuum.
8. The method of claim 7 , wherein at least part of the plurality of particles is heated at a temperature of from about 1450° C. to about 2000° C. under a vacuum for about 3 to about 8 hours.
9. The method of claim 7 , wherein the plurality of particles comprises [YAG:Ce] powder.
10. The method of claim 1 , wherein said phosphor translucent ceramic comprises a composition of (A 1-x E x ) 3 B 5 O 12 , wherein
A is Y, Gd, La, Lu, Tb, or a combination thereof;
x is from about 0.00005 to about 0.1;
B is Al, Ga, In, or a combination thereof; and
E is Ce, Eu, Tb, Nd, or a combination thereof.
11. The method of claim 10 , wherein x is from about 0.0001 to about 0.01.
12. The method of claim 10 , wherein x is from about 0.001 to about 0.005.
13. The method of claim 10 , wherein A is Y.
14. The method of claim 10 , wherein E is Ce.
15. The method of claim 10 , wherein B is Al.
16. A method of increasing the luminescence efficiency of a translucent phosphor ceramic, comprising:
heating the translucent phosphor ceramic under a reducing atmosphere at a temperature effective to increase the luminescence efficiency of the translucent phosphor ceramic, wherein the translucent phosphor ceramic comprises a rare earth doped phosphor material having a garnet structure.
17. The method of claim 16 , wherein the rare earth doped phosphor material is YAG:Ce.
18. The method of claim 16 , wherein the increase in luminescence comprises an at least about 10% increase in emission relative to the translucent phosphor ceramic before the heating under a reducing atmosphere.
19. The method of claim 16 , wherein the temperature is lower than the melting point of the translucent phosphor ceramic.
20. The method of claim 16 , wherein the temperature is from about 1200° C. to about 1800° C.