Hitachi, Ltd.

Koichi Mitobe

Seikichi Tanno

Yasuhiko Uehara

Osamu Matsuzaki

Michio Abe

In a method of manufacturing a color picture tube of the type comprising the steps of coating phosphors of three primary colors on the inner surface of the face plate of the color picture tube to form dots or stripes of the phosphors, applying an acrylic resin emulsion on the dots or stripes of the phosphors to form an acrylic resin film, vapor depositing metal onto the film to form a metallic reflecting film, subjecting the acrylic resin film to a pyrolysis for decomposing it into gases, and removing the gases, the acrylic resin emulsion comprises a plurality of emulsions respectively containing conventional acrylic resin and normal butyl methacrylate resin. The normal butyl methacrylate resin is mixed with the conventional acrylic resin at a ratio of 5 to 40% by weight. According to this method, it is possible to prevent bulging of the metallic reflecting film during baking step while minimizing the number of the pin holes and cracks of the metallic reflecting film so as not to decrease the brightness of the reproduced picture.

Method of manufacturing color picture tubes

In a process for the production of color television picture tubes which comprises at least the step of forming a phosphor layer on the inner surface of a panel, the step of coating said inner surface of the panel including said phosphor layer with an aqueous emulsion of a water-insoluble film-forming resin to form a volatilizable substrate layer, the step of forming a metal film on the substrate layer and the step of volatilizing the organic substances, a color television picture tube in which the blister or separation of the metal film can be prevented in said volatilization step and the undecomposed resin does not remain and which has an improved brightness can be produced by forming said substrate layer from at least two layers each of an emulsion, adding colloidal silica, an aqueous ammonium oxalate solution and aqueous hydrogen peroxide to the first layer emulsion, and adding polyvinyl alcohol-boric acid complex and a small amount of ammonium hydroxide to the emulsion of the layer contacting directly with said metal film.

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Chiba, Japan

Koichi Mitobe