IMPROVED ELECTROLUMINESCENT PHOSPHORS.
RADIO CORP OF AMERICA LANCASTER PA
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The report describes the reeresults ofo of sstudies on the pererformannce characteristics of electroluminescent EL zinc sulfoselenide phosphor powders in plastic dielectrics. The objective of the investigation was to develop phosphors which yielded exceptional brightness under pulsing conditions as well as improved performance under continuous excitation at both high and low voltages. Phosphors were evaluated under short bursts of AC pulsed excitation with the frequency within the pulse varying from 20-100kc. About 5000 ft. L. of brightness was obtained during pulse intervals and maximum bursts were measured close to 10,000 ft. L. Under continuous excitation at 420 cps, three selected phosphors emitting in the green-yellow, light yellow and deep yellow region displayed initial brightneessssentthgiightnesses of about 97, 60 and 33 ft. L. The maintenance hours to one-half of initial brightness of these same layers was about 2200, 4500, and 8000 hours respectively. Phosphors were also evaluated in thin low voltage layers at 25 and 50 volts. At 1500 cps, the brightnesses varied from 2.5 to 24 ft. L. while the maintenance was in the range of 150 to 500 hours. Author