Patent ID: 7422703

Claim:
A process of preparing a phosphor fluoride particle that emits light in the visible wavelength range when excited by long wavelength light that has a uniform particle size of less than 350 nanometers, which process comprises: a) preparing an aqueous solution of soluble salts of a phosphor host, an absorber/emitter pair and a rare-earth metal chelator; and b) contacting said prepared aqueous solution of soluble salts of said phosphor host, absorber/emitter pair and rare-earth metal chelator with an aqueous fluoride-containing compound at a temperature ranging from about 0° C. to about 100° C. for a sufficient time to obtain a precipitate of a phosphor fluoride particle; and c) heating said precipitate at a temperature ranging from about 300° C. to about 450° C. for a time ranging from about 1 hour to about 10 hours to obtain a phosphor fluoride particle that emits light in the visible wavelength range when excited by long wavelength light that has a uniform particle size of less than 350 nanometers.