Claims
- 1. An electroluminescent phosphor having the general formula ZnS:Cu,Cl,Au, a halflife of at least about 900 hours, and x and y color coordinates where the x color coordinate is from about 0.156 to about 0.196 and the y color coordinate is from about 0.370 to about 0.430.
- 2. The electroluminescent phosphor of claim 1 wherein the phosphor has a halflife of at least about 1100 hours.
- 3. The electroluminescent phosphor of claim 1 wherein the phosphor has a halflife of at least about 1300 hours.
- 4. The electroluminescent phosphor of claim 1 wherein the phosphor has an initial brightness of at least about 28 fL.
- 5. The electroluminescent phosphor of claim 1 wherein the phosphor has a y color coordinate of about 0.422.
- 6. The electroluminescent phosphor of claim 1 wherein the amount of gold in the phosphor is about 0.5 .+-.0.2 ppm.
- 7. The electroluminescent phosphor of claim 1 wherein the phosphor has a copper concentration of about 0.06 wt. % and a chlorine concentration of about 0.03 wt. %.
- 8. The electroluminescent phosphor of claim 1 wherein the x color coordinate is from about 0.162 to about 0.202 and the y color coordinate is from about 0.425 to about 0.485.
- 9. The electroluminescent phosphor of claim 8 wherein the phosphor has a halflife of at least about 1200 hours.
- 10. The electroluminescent phosphor of claim 8 wherein the phosphor has a halflife of at least about 1400 hours.
- 11. A method for increasing the halflife of a ZnS:Cu electroluminescent phosphor comprising:
- blending amounts of zinc sulfide, a copper source, a gold source and a chloride flux to form a mixture;
- firing the mixture at a temperature from about 900.degree. C. to about 1400.degree. C. for about 2 hours to about 8 hours to form a zinc sulfide material containing copper, chlorine and gold;
- subjecting the zinc sulfide material to a low intensity milling for between about 190 minutes to about 280 minutes to form a milled material;
- blending the milled material with an amount of zinc sulfate and an amount of copper sulfate; and
- refiring the blended milled material at a temperature from about 500.degree. C. to about 1000.degree. C. for about 1 to 5 hours to form an electroluminescent phosphor.
- 12. The method of claim 11 wherein the amount of gold in the mixture is from about 15 to 88 ppm.
- 13. The method of claim 11 wherein the phosphor contains copper and chlorine.
- 14. The method of claim 11 wherein an amount of a manganese source is added to the mixture in order to produce a manganese and copper coactivated phosphor.
- 15. An electroluminescent lamp comprising:
- a first electrode, a first layer of dielectric material adjacent to the first electrode, a second layer of a dielectric material adjacent to the first layer;
- the second layer containing an electroluminescent phosphor having a general formula ZnS:Cu,Cl,Au, a halflife of at least about 900 hours, and x and y color coordinates where the x color coordinate is from about 0.156 to about 0.196 and the y color coordinate is from about 0.370 to about 0.430; and
- a second electrode adjacent to the second layer of dielectric material.
- 16. The electroluminescent lamp of claim 15 wherein the phosphor has a halflife of at least about 1100 hours.
- 17. The electroluminescent lamp of claim 15 wherein the phosphor has a halflife of at least about 1300 hours.
- 18. The electroluminescent lamp of claim 15 wherein the phosphor has an initial brightness of at least about 28 fL.
- 19. The electroluminescent lamp of claim 15 wherein the phosphor has a y color coordinate of about 0.422.
- 20. The electroluminescent lamp of claim 15 wherein the amount of gold in the phosphor is about 0.5 .+-.0.2 ppm.
- 21. The electroluminescent lamp of claim 15 wherein the phosphor has a copper concentration of about 0.06 wt. % and a chlorine concentration of about 0.03 wt. %.
- 22. The electroluminescent lamp of claim 15 wherein the x color coordinate is from about 0.162 to about 0.202 and the y color coordinate is from about 0.425 to about 0.485.
- 23. The electroluminescent lamp of claim 22 wherein the phosphor has a halflife of at least about 1200 hours.
- 24. The electroluminescent lamp of claim 22 wherein the phosphor has a halflife of at least about 1400 hours.
CROSS-REFERENCES TO RELATED APPLICATION
This application is related to U.S. application Ser. No. 08/637032, filed concurrently herewith, which is incorporated herein by reference.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4859361 |
Reilly et al. |
Aug 1989 |
|
5110499 |
Reilly |
May 1992 |
|
Foreign Referenced Citations (2)
Number |
Date |
Country |
4-270780 |
Sep 1992 |
JPX |
WO 9116722 |
Oct 1991 |
WOX |