process for the production of the screen image of a electrophotographique reproductive tract of colour television pictures

摘要

1498602 Multi-colour electro-photographic processes PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 7 Jan 1976 [10 Jan 1975] 00487/76 Heading G2C [Also in Division H1] A method of electro-photographically manufacturing a colour TV display tube screen comprises providing combustible conducting and photo-conducting coatings, providing a first pattern of phosphor by uniformly charging the photo-conducting coating, imagewise exposing and precipitating phosphor particles whose charge is opposite to that with which the p/c is charged in an apolar dispersion agent, the analogous provision of at least one subsequent pattern of phosphor, and finally heating to remove the conducting and photo-conducting coating, wherein before the provision of a subsequent charge pattern and after the provision of a phosphor pattern, the screen is wetted with a solution of an antistatic agent in an apolar solvent, the solvent having an electrical conductivity of 10SP-14/SP #SP-1/SP cmSP-1/SP, and is then dried. The antistatic agent may be a metal soap of a multi-valent metal or a mixture of such soaps, the solution having an electrical conductivity between 5 x 10SP-12/SP and 10SP-10/SP #SP-1/SP cmSP-1/SP (e.g. 10 Î 10SP-12/SP to 80 Î 10SP-12/SP #SP-1/SP cmSP-1/SP). Specific agents are disclosed. A light absorbing coating may be provided between the phosphor patterns by uniformly charging, exposing, and precipitating charged light absorbing particles from a dispersion in an apolar liquid. The method reduces colour contamination.