METHOD FOR PRODUCING ELECTROLUMINESCENT PHOSPHOR WITH SMALL PARTICLE SIZE AND POWDER HAVING D50 VALUE OF NOT MORE THAN 10 amp;mu;m

摘要

PROBLEM TO BE SOLVED: To provide a method for producing an electroluminescent phosphor with a small particle size, and to provide a powder having a D50 value of not more than 10 μm.;SOLUTION: This electroluminescent phosphor powder contains zinc sulfide particles (the particles have such a particle size distribution that a D50 value thereof is not more than 10 μm) activated by copper, wherein the powder comprises particles of which not more than 25% have a particle size of ≥15μm and/or the powder comprises particles having brightness of ≥15 ft-L when measured after 24 hr. The powder is produced by a method comprising together mixing zinc sulfide doped by copper, zinc oxide, sulfur, and a chloride-containing flux, subjecting the mixture to first firing, rapidly cooling the mixture down to a temperature of lower than 100°C, kneading the mixture, and subjecting the mixture to second firing, so that the powder is given. Further, the powder may be elutriated for the purpose of giving the electroluminescent powder having a narrow particle size distribution (more than 90% of the particles have a particle size in a range of about 5 μm to about 15 μm). A process for elutriating the powder may be omitted, by more strictly controlling a temperature of the first firing (while the particle size distribution is somewhat widen).;COPYRIGHT: (C)2007,JPO&INPIT