GB888839A - Television pick-up tube - Google Patents

Abstract

888,839. Television pick-up tubes; colour television. PYE Ltd. April 24, 1958 [April 24, 1957], No. 13091/57. Class 39(1) A television pick-up tube comprises a target consisting of a transparent support 61, Fig. 9 carrying two transparent conducting signal plates 62, 64 which are insulated from each other and extend over the target area, at least one of the plates 64 being constituted by spaced elemental areas distributed over the surface of the target with the areas in optical register with similar spaced areas of a light modifying filter 63 through which light from an object has to pass in impinging on photo-active material on the target. In Fig. 9 the photoactive material is located on the outer face of signal plate 64 and on the areas of the face of plate 62 exposed through the perforation in the insulator 60, filter 63 and plate 64. With a magenta filter 63, signals corresponding to both red and green components are produced at the signal plate 62 and to red component only at plate 64 and these signals may be utilised for colour television transmission as described in Specification 888,838. The photoactive material may be a photoconductive layer as above applied in contact with both signal plates or may be a photoemissive layer applied as a mosaic on insulating material interposed between the photo-emissive material and the opposing signal plate. In another embodiment the signal plates are in the form of interleaved strips 25, 25a, Fig. 5 formed on a transparent support having contiguous areas 22, 24 Fig. 4 in two different planes with filter material 21 under the signal plate 25. In another embodiment, Fig. 7, V-shaped grooves 31 are formed in a plain glass support 30 and one face of each groove is provided with a filter 32 (e.g. transmit red and reflect green) and a signal plate 36 and the other face is provided with a filter 33 (e.g. transmit green and reflect red) and a signal plate 35 with the ends of associated signal strips being connected together, the whole surface being provided with a photoconductive layer. It is stated that by using appropriately polarised filters the tube may be used in a steroscopic television system.