Claims
- 1. A light emitting device comprising:
a light output; a light source producing light including wavelengths of 530 nm or less; and a wavelength transformer located between the light source and the light output, comprising Sr1-xCaxGa2S4:yEu2+·zGa2S3, where x is 0.0001 to 1, y is a value defining sufficient Eu2+ to provide luminescent emission, and z is 0.0001 to 0.2 based on the mole amount of SrxCa1-xGa2S4, the wavelength transformer effective to increase the light at the light output having wavelength between 535 nm and 560 nm.
- 2. The light emitting device of claim 6, wherein z is 0.001 to 0.2.
- 3. The light emitting device of claim 1, wherein z is 0.001 to 0.1.
- 4. The light emitting device of claim 1, wherein y is 0.001 to 0.1 based on the mole amount of Sr1-xCaxGa2S4.
- 5. The light emitting device of claim 4, wherein y is 0.01 to 0.08
- 6. The light emitting device of claim 4, wherein y is 0.01 to 0.04.
- 7. The light emitting device of claim 1, wherein the phosphor has an emission peak of 535 nm to 560 nm.
- 8. The light emitting device of claim 7, wherein the emission peak has a bandwidth of 50 nm or less under excitation with an emission source at 440 nm±40 nm.
- 8. A method of making a strontium calcium thiogallate phosphor of formula Sr1-xCaxGa2S4:yEu2+·zGa2S3, where x is 0.0001 to 1, y is a value defining sufficient Eu2+ to provide luminescent emission, and z is 0.0001 to 0.2 based on the mole amount of Sr1-xCaxGa2S4, the method comprising:
forming a composition of sulfate salts of gallium, divalent europium, calcium and, if x is not 1, strontium; and firing the composition under hydrogen sulfide.
- 9. The method of claim 8, wherein z is 0.001 to 0.2.
- 10. The method of claim 8, wherein where the amount of gallium is tuned to the range of 0.1 to 7% in excess of the stoichiometric amount of SrxCa1-xGa2S4:yEu2+.
- 11. The method of claim 8, further comprising:
a second firing of the composition following the firing under hydrogen sulfide.
- 12. The method of claim 11, wherein the first firing is conducted at 500 to 850 degrees C.
- 13. The method of claim 12, wherein the second firing is conducted at 750 to 950 degrees C.
- 14. The method of claim 12, wherein the product of the first firing is ground prior to the second firing.
- 15. The method of claim 8, wherein z is 0.001 to 0.1.
- 16. The method of claim 8, wherein y is 0.001 to 0.1 based on the mole amount of Sr1-xCaxGa2S4.
- 17. The method of claim 16, wherein y is 0.01 to 0.08
- 18. The method of claim 16, wherein y is 0.01 to 0.04.
- 19. The method of claim 8, wherein the phosphor has an emission peak of 535 nm to 560 nm.
- 20. The method of claim 19, wherein the emission peak has a bandwidth of 50 nm or less under excitation with an emission source at 440 nm±40 nm.
Parent Case Info
[0001] This application claims the priority of U.S. Provisional Application No. 60/463,883, filed Apr. 21, 2003
Provisional Applications (1)
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Number |
Date |
Country |
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60463883 |
Apr 2003 |
US |