Cerium-activated calcium sulfide phosphor which is sensitized to respond both to short wavelength and long wavelength ultraviolet excitation

Claim 1

A PHOSPHOR COMPOSITION WHICH IS RESPONSIVE BOTH TO SHORT WAVELENGTH AND LONG WAVELENGTH ULTRAVIOLET EXCITATION TO PRODUCE VISIBLE RADIATIONS, SAID PHOSPHOR COMPOSITION HAVING A CALCIUM SULFIDE MATRIX AND ACTIVATED BY TRIVALENT CERIUM IN AMOUNT OF FROM ABOUT 10**5 TO 10**-2 GRAM-ATOM PER GRAM-MOLE OF SAID PHOSPHOR MATRIX, AND SAID PHOSPHOR IS BOTH SENSITIZED AND COACTIVATED BY ONE OF THE COMBINATION OF: A. CUPROUS COPPER SENSITIZER IN AMOUNT OF FROM ABOUT 10**-5 GRAM-ATOM TO 5 X 10**-3 GRAM-ATOM PER GRAM-MOLE OF SAID SULFIDE MATRIX PLUS FLUORINE AS COACTIVATOR, B. STANNOUS TIN SENSITIZER IN AMOUNT OF FROM ABOUT 10**-5 TO 10**-1 GRAM-ATOM PER GRAM-MOLE OF SAID SULFIDE MATRIX PLUS AT LEAST ONE OF FLUORINE AND CHLORINE AS COACTIVATOR, AND C. PLUMBOUS LEAD SENSITIZER IN AMOUNT OF FROM ABOUT 10**6 TO 10**-2 GRAM-ATOM PER GRAM-MOLE OF SAID SULFIDE MATRIX PLUS AT LEAST ONE OF THE CHLORINE AND BROMINE AS COACTIVATOR, SAID COACTIVATOR IS PRESENT IN GRAM-ATOM AMOUNT AT LEAST EQUAL TO THE TOTAL GRAM-ATOMS OF SAID CERIUM ACTIVATOR PLUS SAID SENSITIZER IN SAID PHOSPHOR, AND SAID COACTIVATOR HAVING BEEN INCLUDED IN THE RAW MIX USED TO PREPARE SAID PHOSPHOR AS A SALT FREE FROM ANY ALKALI METAL.