Patent GB-477326-A (GB)
Title: Improvements in or relating to apparatus for transmitting images of an object to a distance
IPC: H01J29/02
Filed: 1936-05-18
Abstract: 477,326. Discharge apparatus. ZEITLINE, V., ZEITLINE, A., and KLIATCHKO, V. May 18, 1936, No. 14064. Convention date, May 18, 1935. [Classes 39 (i), 40 (iii), and 40 (v)] Apparatus for transmitting images of an object to a distance comprises an optical system for projecting an image upon a photoelectric screen within an enclosing envelope, the resultant photo-emission producing an electron image, one or more intermediate electrodes in the envelope having properties of photo- or secondary emission or both and producing, in the operating conditions, a corresponding amplified electron image, and a final electrode in the envelope arranged to accumulate electrical charges, corresponding to the amplified electron image, which are neutralized to produce signal currents by a scanning beam. In one form, Fig. 1, the image is thrown upon the photo-electric screen P1, and the electron image produced is accelerated by the gauze anode A, and falls on the fluorescent screen Fl. The light from the screen F1 falls on a photo-electric layer P2, which emits an amplified electron image which is again amplified by the similar system A2, F2, P3. The screens F1, F2, P2, P3 are deposited on opposite sides of transparent plates S1, S2. The photo electrons from the layer P3, which is mosaic in character, are collected by the anode A3 and leave a positive charge image on P3. This charge image is scanned by a light beam RL and the resultant strong emission brings every element to the potential of A3. The signal may be obtained from the anode A3 or capacitatively from F2. The magnetic field H produces two or more image planes in which the amplifying electrodes are situated. The carrier plates S1, S2 may be made pervious to electrons, when secondary emission from both the fluorescent and photo-electric electrodes may be used to assist the amplification; or single pervious electrodes may amplify by secondary emission alone. The intermediate electrodes may be conducting or non-conducting. In a modification, shown in Fig. 2, an electron scanning beam R is utilized which traverses an electrode F5 upon which an amplified charge image is stored in any of the ways previously described, the signal being derived from the anode or screen Ap or capacitatively from any of the screens F1-F4, preferably F4. The amplification may be increased by permitting an optical reaction between a fluorescent electrode and a closely adjacent preceding photo-electrode. This reaction may be controlled by displacing the maximum spectral sensitivities of successive screens or by placing an opaque layer between screens which would produce excessive reaction. In the form shown in Fig. 2, a further " electric reaction " may be produced by feeding a portion of the signal current through the amplifier Am to a control grid G or Wehnelt cylinder which modulates the scanning beam. Specification 442,666 is referred to. The Specification as open to inspection under Sect. 91 describes a modification, Fig. 1 (Cancelled, not shown), in which the photoelectric layer is separated by a metal sheet or grid or a conductive solution from a scanned fluorescent or secondary-emitting electrode and also includes the subject-matter of Speci. fication 478,499. This does not appear in the Specification as accepted.