GB845391A - Radiation amplifier - Google Patents

Abstract

845,391. Electroluminescence. STANDARD TELEPHONES & CABLES Ltd. Sept. 26, 1958 [Sept. 27, 1957], No. 30825/58. Class 39(1). A radiation amplifier comprises at least two co-planar parallel strips of conductive material between which are arranged an electroluminescent strip abutting one conductive strip and a strip of photo-conductive material abutting the electroluminescent strip and the other conductive strip so that when the conductive strips are connected to a source of alternating current, thereby forming a series circuit of the electroluminescent and photoconductive materials, a projected image may impinge upon and the resulting luminescent image be viewed from the same surface of the device. As shown, a photo-conductive sheet 4 is formed with a plurality of parallel grooves in which are embedded strips 9 of electroluminescent material, e.g. a copper-activated zinc oxide and zinc sulphide mixture, and conductive strips 10, e.g. of copper. Alternate conductive strips are connected to terminal 12 and the remainder to terminal 13 for connection across a source of alternating current. The device also includes a transparent supporting plate 2, e.g. of glass or plastic, and an opaque supporting plate 18. Light-alternating or opaque material may be interposed between the electroluminescent strips and the surrounding photoconductive material in order to prevent light feedback. Specification 749,798 is referred to.