GB943985A - Improvements in or relating to electroluminescent devices - Google Patents

Abstract

An electroluminescent device has a light-transmitting film electrode provided by a multilayer film comprising a layer of bismuth oxide on the surface of a transparent base member and a layer of gold on the bismuth oxide layer. The bismuth oxide layer can be between 100<\>rA and 500 <\>rA thick and the gold layer between 70 <\>rA and 150 <\>rA thick and formed by sputtering. A second layer of bismuth oxide, of about the same thickness as the first layer, can be formed on the gold layer. The multi-layer film electrode can extend over part only of the transparent base member, by sputtering through a mask, to form a display device. The base member can be of glass or methyl methacrylate and a layer of insulating material, e.g. "Paralac 10" (Registered Trade Mark), of high dielectric constant can be formed between the phosphor layer and the other electrode. The transparent base member can be in the form of flat or curved plates or in the form of hollow members, e.g. a hollow glass cylinder filled with dry nitrogen at atmospheric pressure on the inside surface of which the layers are formed by sputtering through a mask as described in Specification 915,568, to form a display legend. The second electrode can be of aluminium paint and connections to the electrodes can be made through the ends of the cylinder. The phosphor layer and the second electrode can be formed by an evaporation process.