Electroluminescent phosphor powders, methods for making phosphor powders and devices incorporating same
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 phosphor powder batch comprising composite phosphor particles containing at least a first phase and at least a second phase dispersed within said first phase, wherein one of said phases is an electroluminescent phosphor and wherein said composite particle average size is between 0.1 and 10 microns.
2. The phosphor powder batch of claim 1 wherein the average particle size is from about 0.1 to 5 microns.
3. The phosphor powder batch of claim 1 wherein one of said phases is inorganic.
4. The phosphor powder batch of claim 1 wherein one of said phases is a metal oxide.
5. The phosphor powder batch of claim 1 wherein one of said phases is a metal sulfide.
6. The phosphor powder batch of claim 1 wherein the composite particles have substantially spherical morphology.
7. The phosphor powder batch of claim 1 wherein the crystallite size of one of said phases is at least 25 nm.
8. The phosphor powder batch of claim 1 wherein said first phase is uniformly distributed through said second phase and said second phase is a phosphor.
9. The phosphor powder batch of claim 1 wherein at least 80% of said composite particles are within twice the average size.
10. The phosphor powder batch of claim 1 wherein both phases are phosphor compounds.
11. An ink comprising the particles recited in claim 1 .
12. An ink-jet ink comprising the particles recited in claim 1 .