GB1039082A - Picture display apparatus - Google Patents

Abstract

1,039,082. Developing electrostatic images. TOKYO SHIBAURA ELECTRIC CO. Ltd. March 18, 1963. No. 10571/63. Heading G2H. [Also in Division H4] A picture is recorded on a receiving screen Figs. 1 and 2, formed of a transparent base plate 11 (glass or methacrylic resin), a transparent conductive layer 12 and an insulating layer 13 by means of needle-like electrodes 17 which are connected to receive a voltage representative of the picture and are traversed across the screen on an endless belt 16 whilst relative motion between the screen and electrode assembly is effected in the direction 21. A developing device 15 in the form of permanent magnet rod 19 rotating in a mixture of iron oxide and a developer powder is provided on the trailing side of electrode assembly and functions to transfer powder to the screen point-bypoint in accordance with the electric charge pattern created by the electrodes, whilst a similar device 15<SP>1</SP> on the leading side of the electrode assembly functions to remove a previous recording. The arrangement is intended for television and advertising. For radar purposes, Fig. 6, an array of electrodes 24 in side-by-side relation is disposed along a radius of the screen and rotated about the centre, connection of signals to the electrodes being effected in sequence by a commutator 23 or electronic switch. The arrangements are constructed to be moisture proof to prevent loss of charge by leakage and the chamber for the developing powder contains a moisture absorbing agent. Furthermore, the surface of the insulating layer 33, Fig. 7 opposite to that in contact with the conductive layer 32 may be provided with a mosaic of conductive elements 34 which are cemented to the layer with an insulating binder. Reference is made to the use of a wholly transparent receiving screen.