GB458654A - Improvements in or relating to electro-optical systems - Google Patents

Abstract

458,654. Television. STANDARD TELEPHONES & CABLES, Ltd., 63, Aldwych, London.-(Assignees of Hefele, J. R., and Ives, H. E.) June 2, 1936, No. 15402. Convention date, May 31, 1935. [Class 40 (iii)] In a colour television system, an object O is scanned at the transmitter T by a disc 12 having three apertures 1, 2, 3 in place of each aperture of the usual single spiral, all the apertures of spiral 1 being covered with red filters, those in spiral 2 with green filters and those in spiral 3 with blue filters. The light reflected from the object O is impressed on photo-electric cells 17, 18, 19 which are either inherently colour selective or made so selective by the provision of filters 20, 21, 22. If desired, a plurality of groups of colour selective lightsensitive cells may be employed. The image currents produced by the cells are transmitted over separate channels and applied at the receiver R to strip light sources 29, 30, 31 which either inherently produce light radiations of the different wavelengths or colours or have associated therewith appropriate filters 32, 33, 34. The light from these sources is directed on to a mirror helix 37 constructed as described in Specification 402,401, the light being reflected from the helix on to an observer's eye E. The spacing apart of the apertures in the disc 12 is determined so as to compensate for the physical separation of the light sources at the receiver and so obtain superimposition of the three images. According to a modification, Figs. 7-9 (not shown), a lenticular photographic film, preferably prepared by the process known under the Registered Trade Mark " Kodacolor," is scanned at the transmitter and delay networks are inserted in the channels leading to two of the light sources at the receiver in order to obtain superimposition of the images. The delay networks may alternatively be inserted at the transmitter or at any point in the transmission lines. If desired, the mirror helix 37 may be replaced by a lensed disc or other similar scanning device.