Improvements relating to the manufacture of fluorescent screens

699,660. Luminescent materials. EDISON SWAN ELECTRIC CO., Ltd. May 6, 1952 [June 18, 1951], No. 14450/51. Class 39(i) A process of forming a fluorescent screen on a surface, particularly the end wall of a cathode ray tube, consists in first forming a cushioning layer of liquid over said surface, the cushioning layer comprising a solution of a soluble salt which is capable of reacting to give an insoluble silicate, and then adding a fluorescent material in suspension in a solution of a soluble silicate, with which is mixed a sparingly soluble salt which also reacts to give an insoluble silicate, allowing the resultant suspension to settle on to the surface and thereafter decanting surplus liquid. The cushioning layer may comprise a solution of a soluble barium salt, such as the nitrate or acetate, and the mixture added may include calcium metaborate and potassium silicate. The mixture may be added to the cushioning layer through a funnel or rose. It is stated that barium silicate is formed on the surface and that a layer of calcium silicate is formed on the surface of the particles of fluorescent material. The process can be applied to screens having phosphors of different colours, each phosphor being deposited separately and masks being placed over the surface to limit the areas'on which any individual phosphor is deposited.