Process for producing electroluminescent phosphors

Claim 1

A PROCESS FOR PRODUCING AN ELECTROLUMINESCENT PHOSPHOR FROM A BASE MATERIAL OF THE ZINC SULFIDE TYPE WHEREIN UP TO 20 MOLE PERCENT OF CADUIUM CAN BE SUBSTITUTED FOR AN EQUIVALENT MOLE PERCENT OF ZINC AND WHEREIN UP TO 30 MOLE PERCENT OF SELENIUM CAN BE SUBSTITUTED FOR AN EQUIVALENT MOLE PERCENT OF SULFUR, SAID PROCESS COMPRISING THE STEPS OF MIXING SAID MATERIAL WITH A COPPER ACTIVATOR AND AT LEAST ONE HALIDE COACTIVATOR SELECTED FROM THE GROUP CONSISTING OF CHLORIDE, IODIDE AND BROMIDE, FIRING SAID MIXTURE TO A TEMPERATURE FALLING WITHIN THE APPROXIMATE RANGE 1000*-1300* C. TO PRODUCE AN INTERMEDIATE PRODUCT HAVING ABSOLUTE ACTIVATOR AND COACTIVATOR CONCENTRATIONS FALLING WITHIN THE SAME APPROXIMATE RANGE OF 1X10**-4-5X10**-3 GRAM ATOMS PER MOLE OF SAID MATERIAL, MILLING SAID INTERMEDIATE PRODUCT TO REDUCE THE PARTICLE SIZE THEREOF, ANNEALING THE MILLED PRODUCT AT A TEMPERATURE FALLING WITHIN THE RANGE 600*-1000* C., MIXING AT LEAST 1X10**5 ADDITIONAL GRAM ATOMS PER MOLE OF SAID ACTIVATOR WITH SAID ANNEALED PRODUCT, AND FIRING SAID COPPER-AUGMENTED ANNEALED PRODUCT TO A TEMPERATURE FALLING WITHIN THE APPROXIMATE RANGE 700*-950* C. TO PRODUCE SAID ELECTROLUMINESCENT PHOSPHOR.