GB786553A - Improvements in or relating to the projection of televised images - Google Patents

Abstract

786,553. Television; light modulating. SOC. GENERALE D'ELECTRONIQUE. June 14, 1954 [June 15, 1953 ; May 26, 1954], No. 17452/54. Class 40 (3). An arrangement for reproducing television pictures employs a light modulating device comprising a deformable reflecting metallic sheet F supported at a short distance from an insulating support I (consisting of the end wall of a cathode-ray tube T) by means of a plurality of spaced elements H, the arrangement being such that when the sheet is scanned by an electron beam modulated by the television signals, the resulting deformations produced by electrostatic attraction between the sheet and the support I modulate, in co-operation with the grids G1, G2 of a Toeplar optical system, light from a local source S and thereby project an image corresponding to the modulating signals on to screen E. The sheet F may be either flat (Fig. 2), or undulating, as shown in Fig. 6 (the elements H being castellated in this case) in the absence of scanning the electron beam being modulated by signals having maximum intensity representative of picture white in the former and representative of picture black in the latter case. In alternative constructions, the sheet F may be formed with alternate thick and thin strip portions (Fig. 3, not shown) ; the spacing elements H may each be formed from two members, one being transparent and the other opaque and reflecting (Fig. 5, not shown), and the whole device may be made spherical instead of plane so that it acts as a concave mirror which directly produces an image of the grid G1 on the grid G2, thus enabling the lens 01 to be dispensed with (Fig. 7, not shown). Specifications 684,706, 701,543 and 776,665, [Group XL (a)], are referred to.