GB865665A - Improvements in or relating to scanning display devices - Google Patents

Abstract

865,665. Television. MULLARD Ltd. July 1, 1957 [Oct. 4, 1956], No. 30359/56. Class 40(3) In a television receiver successive lines of the picture produced by scanning an elongated phosphor strip P 1 (in an elongated cylindrical cathode-ray tube T), in the line direction only, are imaged by means of the operative one of three moving cylindrical lenses L (supported by a carrier C rotated at one-third frame frequency) to provide the frame-deflection components on to a hyperbolic mirror H. An observer looking at light coming from direction Z thus sees a complete picture, B B<SP>1</SP>. The arrangement of cathode-ray tube T and the carrier C may be similar to that described in Specification 827,851 and the cathode-ray tube itself may be the same as that described in either Specifications 865,663 or 865,666. When colour reproduction is required the tube is provided with three phosphor strips P producing three different component colours and the colour trace produced by applying a "spot-wobble" of either sinusoidal or sawtooth waveform to the (single) electron beam. For reproducing colour signals of the N.T.C.S. type the frequency of the "spot-wobble" is made equal to that of the chrominance subcarrier so that the "I" and "Q" signals are decoded at the electron gun. Alternatively three electron beams may be employed to scan the three phosphor strips. For frame sequential colour display the lenses L may be associated with appropriate colour filters or may themselves be arranged to act as colour filters. When both monochrome and colour operation is required the tube may be provided with a phosphor strip producing the monochrome radiation in addition to the three colour phosphor strips. For stereoscopic operation the lenses L may be polarized in different directions. The rotation of the carrier C may be synchronized with the input signals by varying the saturation of a reactor controlled device which governs the (induction) motor driving the carrier in accordance with variations in phase between the frame synchronizing signals and a sawtooth wave generated by a suitably shaped rotor on the carrier driving shaft. Specification 846,544 also is referred to.