GB1340403A - Electron beam recording materials - Google Patents

Abstract

1340403 Electron beam apparatus FUJI PHOTO FILM CO Ltd 19 April 1971 [3 Feb 1970] 20935/71 Heading H1D [Also in Division G2] Distortion of the image produced on a silver halide photo-sensitive layer by an electron beam due to charge accumulation on the layer, is prevented by a metal film 10A to 3 microns thick which is evaporated over the layer, an intermediate protective layer being provided to prevent chemical reaction between the metal and the layer. The metal film is preferably 10<SP>2</SP>-10<SP>4</SP>Š thick and may be of cadmium, zinc, selenium, magnesium, indium, silver, aluminium, copper, gold, germanium, titanium, antimony, bismuth, lead, manganese, gallium, beryllium or tin and should be evaporated in a high vacuum at a temperature below 1000‹ C. to avoid fogging the silver halide. After exposure the metal film may be removed either before or during the developing and fixing treatment. The protective layer may be watersoluble, alkali-soluble, organic solvent soluble, or water insoluble but water-permeable. Alternatively there may be two layers, the first water-permeable and insoluble in organic solvents and the second water-insoluble and soluble in organic solvents. The protective coat should be 0À1-5 and preferably 0À2-2 microns thick. The silver halide may be an emulsion or an evaporated layer. In one example an emulsion containing silver chloro-bromide is coated on a tri-acetyl cellulose film to a dry thickness of 4 microns and coated with a one micron thickness of gelatine on which zinc is evaporated at 340‹ C. at a pressure of 10<SP>-4</SP> mm. to a thickness of 500Š. After exposure, the zinc is dissolved in acetic acid solution before the developing and fixing processes. In a modification the protective coat is polyvinyl alcohol and the metal is cadmium. In another modification the protective coat is polyvinyl acetate and the metal is magnesium; after exposure, the protective coat is dissolved in methyl alcohol which removes the coat and the metal layer. In a further modification the protective coat is a co-polymer of styrene and maleic anhydride and the metal is zinc, both of which are removed by the developer. In another example the protective coat is 0À7 microns of gelatine covered with a 0À7 micron thickness of a styrene-maleic anhydride copolymer and the metal is zinc, all of which are removed in the developing and fixing processes. Further examples use nitrocellulose and titanium, polyvinyl acetate and aluminium, and nitrocellulose and silver.