PURPOSE: To provide a green light-emitting phosphor which emits green light having a longer wavelength than that of the green light emitted by conventional phosphors, by a method wherein specified amounts of a Cu-activator, an Au-activator, an Al-coactivator and bismuth are incorporated into ZnS host component.
CONSTITUTION: The titled phosphor is composed of ZnS phosphor activated with 5×10-5W3×10-4g (per gram of ZnS) of Cu, 2.5×10-5W1.5×103g of Au, 5× 10-5W10-3g of Al and a very small amount of Bi. The amount of gram atom of Cu must be greater than 1/2 of the sum of the amounts of gram atom of Cu and of gram atom of Au. The amount of Bi which is incorporated into the phosphor, is not more than 100ppm. Cu as the sulfate or the nitrate is added to ZnS, and then calcined. Au as the chloroaurate is added to ZnS, and then calcined. Al as the sulfate or the nitrate is added to ZnS and then calcined. Bi as the sulfate, the nitrate, the sulfide or the halide is added to ZnS, and then calcined.
MATSUHISA NOBORU
OOMATOI SUSUMU
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