GB321935A - System and apparatus relating to television, picture tranmission, telecinematography & the like - Google Patents

Abstract

321,935. Sharma, D. N. Aug. 9, 1928. Television,; copying-telegraphs.-The pictures to be transmitted are recorded on a film which is both light-sensitive and fluorescent. The fluorescent and photographically sensitive film may be coated with an emulsion containing double salts, such as (1) a sulphate or sulphide of manganese, cadmium or zinc together with (2) silver bromide or iodide, by either precipitation or crystallization from a common solution. These salts may be incorporated with the material of the film or may be applied to it as a coating. At the transmitting station (Fig. 1, not shown) the fluorescent kinematographic film, after being inscribed with a sound record and picture record, passes through developing, fixing and washing tanks and an electrically heated drying chamber, stirrers and a drying fan being provided. The film F, Fig. 2, then passes between a cathoderay tube I and a light-sensitive cell 7. A pencil of cathode rays is caused to oscillate in a direction transverse to the direction of movement of the film. fluorescence is excited at the point of incidence of the rays, and affects the lightsensitive cell 7, or not, according to the density of the photographic record at that part of the film. Simultaneously the sound record influences a light-sensitive cell 11, and the output of the cells 7, 11 modulates the two different carrier frequencies. At the receiving station the picture signals influence a pencil of cathode rays which oscillates either in two dimensions so as to reproduce the picture on a fluorescent screen, or in one dimension so that the emergent Lenard rays affect a moving photographic film. 'The intensity of the pencil is varied under the influence of deflecting electrostatic plates to which the received signals are applied. The pencil normally passes through an aperture in a screen but is deflected thence by the signals.