Osram Sylvania Inc.

Brian J Payne

Judy A Belinski-Wolfe

Gregory A Marking

Thomas A Wolfe

Courtney Spencer Warren

There is presented an electroluminescent phosphor powder of copper-activated zinc sulfide particles that has a size distribution with a D50 value of less than 12 &#x3bc;m, and more preferably less than 10 &#x3bc;m. The powder is preferably made by a method that includes the steps of combining copper-doped zinc sulfide with sulfur, zinc oxide and a chloride-containing flux to form a first mixture; preliminarily firing the first mixture and milling the preliminarily fired first mixture to form a milled material having a D50 value of less than or equal to about 5 &#x3bc;m; blending the milled material with sulfur, zinc oxide and a chloride-containing flux to form a second mixture; firing the mixture in a first firing step at a temperature in a range of about 1020&#xb0; C. to about 1080&#xb0; C. to form a hexagonal zinc sulfide material; inducing defects into the hexagonal zinc sulfide material; firing the hexagonal zinc sulfide material in a second firing step at a temperature in a range of about 650&#xb0; C. to about 850&#xb0; C. to form an electroluminescent phosphor; and sifting the electroluminescent phosphor to provide an electroluminescent phosphor powder comprising phosphor particles that have a size distribution with a D50 value of less than 12 &#x3bc;m. The step of inducing defects may be accomplished by milling, mulling or sonification of the mixture.

Electroluminescent phosphor powder with D50 value of less than 12 &#x3bc;m and method of making

The electroluminescent phosphor of this invention is comprised of zinc sulfide activated with copper and iodine and may produce an emission with an x color coordinate from 0.145 to 0.155 and a y color coordinate from 0.085 to 0.095. The phosphor preferably contains from about 0.08 to about 0.90 weight percent (wt. %) copper.

Electroluminescent phosphor

A ZnS:Ag,Al phosphor and method of making are described wherein the ZnS:Ag,Al phosphor exhibits a substantially polyhedral morphology and low particle agglomeration. The method of making includes the use of a mixed sodium chloride and alkaline-earth metal chloride flux. The resulting ZnS:Ag,Al phosphors may be made into finished CRT phosphors having improved CRT screen making properties.

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Sayre, PA, United States of America

Brian J Payne