High brightness orange-yellow-emitting electroluminescent phosphor and method of making
AssigneeOsram Sylvania Inc.
InventorsXianzhong Chen, Robert L. Stevens, Judy A. Belinski-Wolfe, Fuqiang Huang, Chen Wen Fan, Michael A. Maxwell
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Abstract
An orange-yellow-emitting zinc sulfide-based electroluminescent phosphor is described wherein the phosphor has a brightness of greater than 10 foot-Lamberts. More particularly, the phosphor has a brightness of at least about 13 foot-Lamberts and an x color coordinate from about 0.51 to about 0.56 and a y color coordinate from about 0.42 to about 0.48. The zinc sulfide phosphor is activated with manganese, copper, chlorine, and a metal selected from gold and antimony.
Claims19
An orange-yellow-emitting zinc sulfide-based electroluminescent phosphor having a brightness greater than 10 foot-Lamberts and an x color coordinate from about 0.51 to about 0.56 and a y color coordinate from about 0.42 to about 0.48.
An orange-yellow emitting electroluminescent phosphor comprising zinc sulfide activated with copper, manganese, chlorine, and a metal selected from gold and antimony, wherein the phosphor contains about 0.5 to about 1.3 weight percent manganese, about 0.02 to about 0.08 weight percent copper, about 0.002 to about 0.02 weight percent chlorine, 0 to about 0.012 weight percent gold, and 0 to about 0.0007 weight percent antimony.
A method of making an orange-yellow-emitting electroluminescent phosphor comprising:
- (a) forming a mixture of an amount of zinc sulfide, an amount of a copper source, an amount of a manganese source, an amount of zinc oxide, an amount of sulfur, an amount of a chloride-containing flux, and an amount of a source of a metal selected from a gold and antimony;
- (b) firing the mixture at a temperature from about 1100° C. to about 1250° C. for about 3 hours to about 5 hours;
- (c) mechanically working the fired material to introduce defects in the crystal structure;
- (d) washing the fired mixture to remove the chloride-containing flux and copper sulfide residues;
- (e) combining the fired material with an amount of a copper source, an amount of a manganese source, and an amount of zinc oxide to form a second mixture;
- (f) firing the second mixture at a temperature from about 750° C. to about 950° C. for about 2 hours to about 5 hours and fast cooling the fired second mixture;
- and
- (g) washing the second mixture to remove residual copper sulfide.
Dependencies are inferred from the claim text.