"An electroluminescent light-amplifying picture panel"

Abstract

Successful designs of experimental large-area light amplifying picture panels have been evolved using electroluminescent phosphor and a newly developed photoconductive CdS powder. The device to be described is a flat solid-state panel, approximately 12 square, capable of intensifying images of low level visible light. The light may originate from a tungsten source or may consist simply of room light or daylight. Although such amplifiers may be made with differing spectral responses, this particular amplifier has a gain of approximately 15 times using input pictures which are of identical spectral distribution to that of the output picture. The present light amplifier is thus not limited to converter operation as is the case with other devices sometimes classed as light amplifiers which require ultra-violet input images for producing a visible output picture. The response time of the panel, determined basically by the photoconductive material, varies from about .1 second to several seconds, depending on the particular photoconductive powder and the input light level employed. In general, the light amplifier has properties which are common to most amplifiers, that is, it is capable of being cascaded into units of more than one stage, and may be designed to have a specified amount of feedback.