Electroluminescent phosphor powders, methods for making phosphor powders, and devices incorporating same
View Patent ↗Electroluminescent phosphor powders and a method for making phosphor powders. The phosphor powders have a small particle size, narrow particle size distribution and are substantially spherical. The method of the invention advantageously permits the economic production of such powders. The invention also relates to improved devices, such as electroluminescent display devices, incorporating the phosphor powders.
1. A powder batch comprising electroluminescent Y 2 O 3 phosphor particles, wherein said particles have a weight average particle size of from about 0.3 μm to about 5 μm and have a substantially spherical morphology, wherein at least about 80 weight percent of said particles are not larger than about two times said average particle size and wherein the level of impurities in said particles is not greater than about 0.1 atomic percent.
2. A powder batch as recited in claim 1 , wherein said particles comprise a rare earth dopant.
3. A powder batch as recited in claim 1 , wherein said particles comprise Eu as a dopant.
4. A powder batch as recited in claim 1 , wherein at least about 90 weight percent of said particles are not larger than about two times said average particle size.
5. A powder batch as recited in claim 1 , wherein said particles are comprised of crystallites having an average crystallite size of at least about 25 nanometers.
6. A powder batch as recited in claim 1 , wherein said particles have the weight average particle size of from about 0.3 μm to about 3 μm.
7. A powder batch as recited in claim 1 , wherein said particles are comprised of crystallites having an average crystallite size of at least about 40 nanometers.
8. A powder batch comprising electroluminescent Y 2 O 3 phosphor particles, wherein said particles have a weight average particle size of from about 0.3 μm to about 5 μm and have a substantially spherical morphology, wherein at least about 80 weight percent of said particles are not larger than about two times said average particle size.
9. A powder batch as recited in claim 8 , wherein said particles have a weight average particle size of from about 0.3 μm to about 3 μm.
10. A powder batch as recited in claim 8 , wherein said particles are comprised of crystallites having an average crystallite size of at least about 25 nanometers.
11. A powder batch as recited in claim 8 , wherein said particles comprise Eu as a dopant.
12. A powder batch as recited in claim 8 , wherein at least about 90 weight percent of said particles are not larger than about two times said average particle size.
13. A powder batch as recited in claim 1 , wherein the level of impurities in said particles is not greater than about 0.01 atomic percent.
14. A powder batch as recited in claim 8 , wherein said particles are comprised of crystallites having an average crystallite size of at least about 40 nanometers.
15. A powder batch as recited in claim 8 , wherein said particles have a particle density of at least about 95 percent of the theoretical density for said particles.