GB482208A - Improvements in or relating to light-electric translating means and to television transmitters - Google Patents

Abstract

482,208. Light - sensitive cells ; cathode - ray amplifiers ; television. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE. Sept. 24, 1936, No. 25993. Convention date, Sept. 24, 1935. [Classes 39 (i), 40 (iii), and 40 (v)] A light-sensitive cell depends upon the aetino-dielectric effect and comprises a plate electrode 11, Fig. 1, a mesh electrode 12 permeable to light, and a layer 10 of phosphorus having a dielectric constant which varies according to the strength of the illumination incident upon it. For amplification the cell forms one arm of a capacity bridge, one diagonal of which comprises an oscillator 16 while the other diagonal comprises a cathode-ray amplifier 18. The cathode stream 5 oscillates with an amplitude that depends on the illumination of the cell 10, 11, 12, and the electron current passing through an apertured diaphragm 21 varies correspondingly. Amplifying means of the electron-multiplier type, operating by secondary emission, may be provided in the part 6 of the tube. In a television transmitter, Figs. 2 and 3, the picture is projected line by line, by means of a mirror wheel upon a strip 24 of phosphorus which forms part of the dielectric that separates the electrodes 22, 23. A cathode beam 25 is traversed in a direction parallel to the arrows Q by deflecting-plates (not shown) in a perpendicular direction, and is at the same time oscillated along the arrows P, by the voltage applied to plates 22,23 by the oscillator 16. The amplitude of the latter oscillation depends on the dielectric constant at each point x of the layer 24, and the electron current passing through a slit 26 in a diaphragm, which varies accordingly and may act upon electron - multiplying means, serves as picture current for the television transmitter.