GB751404A - Improvements in or relating to electroluminescent sign devices - Google Patents

Abstract

751,404. Electroluminescence. PHILIPS ELECTRICAL INDUSTRIES, Ltd. April 8, 1954 [April 11, 1953], No. 10369/54. Class 39 (1). A mask, opaque at places corresponding to a desired sign, is placed between the phosphor layer and the transparent conductive electrode layer of an electroluminescent device, e.g. a sign or tuning scale. The plate comprises a glass support 3, a thin transparent conductive layer 17 of tin oxide, a layer of synthetic resin 19, a mask 21 of opaque non-conductive lacquer, a layer 23 of electroluminescent material, a second layer 25 of synthetic resin and a conductive silver layer 27. The capacitance of the layer system is used in the oscillator producing the applied potentials. The phosphor and one of the electrode layers are omitted or cut away except at the places in the mask transmitting light. Fig. 3 (not shown) shows the way the mask and the electrode layers in a radio receiver are reduced in size giving a reduction of capacitance sufficient for an oscillator frequency >10,000 c/s. A part of the layer 27 may be insulated from the remainder and given a voltage dependent on the tuning which is indicated by its brightness. Separate waveband scales are given separate systems and may use phosphors of different colours. The control knob of the set may carry a separate electroluminescent layer system to facilitate its control, the lacquer mask 21 may be conductive and be located adjacent to the electrode layer 17.