Abstract: A fluorescent screen formed on the inner surface of the face plate of a color picture tube comprises a plurality of spaced apart light absorbing layers between adjacent matrix windows, light reflection layers formed on the light absorbing layers, stripe shaped three color phosphors respectively formed between adjacent light reflection layers to fill the matrix windows, and a metal back layer covering the light reflection layers and the three color phosphors. Each light reflection layer takes the form of a triangular section having a height substantially equal to the thickness of the three color phosphors and the opposite sides of the triangle incline toward the sides of the matrix windows. The width of each window is equal to the difference between a maximum electron beam diameter and one half the difference between the pitch of the windows and the width of each window.

Abstract: When a water-soluble alcohol having 4 to 6 hydroxyl groups is added to a photosensitive composition comprising a water-soluble polymer substance and a bisazide crosslinking agent, the polymer crosslinking reaction by said bisazide crosslinking agent is promoted and a polymer crosslinkage enough to form an image is produced even at a low exposure dose of ultraviolet ray. Thus, the photosensitive composition is highly sensitized as compared with prior art photosensitive compositions. The alcohol is exemplified by erythritol, pentitol, etc. and is preferably added in an amount of 1 - 100 parts by weight per 100 parts by weight of the water-soluble polymer substance.

Abstract: The present invention affords a process for forming a pattern having a surface area substantially equal to or smaller than area of apertures of shadow-mask through which beams pass on a photoresist film, which contains an acrylamidediacetoneacrylamide copolymer and a water-soluble aromatic bisazide compound, by exposing said photoresist film to light through a mask having the pattern and then developing the film.The use of said photoresist film for the preparation of a phosphor screen of a color picture tube of a black matrix or black stripe type does not require a special technique such as post-etching of a shadow mask and makes it possible to form a three primary color phosphor pattern having a surface area substantially equal to or smaller than the area of apertures of the shadow mask through which lightbeams pass, without mutual "bridging" between phosphor dots. Thus, an excellent phosphor screen of a color picture tube of a black matrix or black stripe type can be prepared.

Abstract: A filter layer for intercepting the undesired light passage is interleaved between the panel of a color cathode ray tube and the photosensitive phosphor coating, the photosensitive phosphor coating is backwardly exposed through the filter layer to actinic radiation of the back exposure to form phosphor elements with good adhesion and position.

Abstract: Surfaces of a perforated mask made of iron are allowed to contact with an acidic aqueous solution of antimony trichloride, e.g., a hydrochloric acid solution to form a thin film of metallic antimony on said surfaces. A protective coating of a phosphate is allowed to be deposited onto said thin film. Thereafter, said surfaces is heated in an oxygen atmosphere to produce a grayish black coating having an excellent thermal emission power. The perforated mask thus treated has no permanent deformation like wrinkles produced at a perforated sheet member and is uniform in color.