Improvements in or relating to arrangements embodying charge storage pick-up tubes

摘要

975,855. Television pick-up tubes. ELECTRIC & MUSICAL INDUSTRIES Ltd. July 24, 1963 [July 24, 1962], No. 28434/62. Heading H1D. In a charge storage pick-up tube having a first photo emissive surface 2, Fig. 2 or 4, on which an optical image is formed (e.g. by lens 6, Fig. 2), a light-transparent target 3, and a second photo-electric surface 4 on the side of the target remote from the first electrode, a scanning light beam is focused (11) on to the second photo emissive surface 4 through the target 3, in Fig. 4 after reflection at 15. Electrons from the first photo-electric surface 2 are focused on to the target by the electro-static lens 7, 8, or magnetically; photo-electrons from the second photo-electric surface 4 are accelerated by the mesh 5 and fall either on to the aluminized phosphor 12 or on to an electron multiplier. The scanning light beam may enter the tube through the first photo emissive surface 2, Fig. 2, either by being of a wavelength to which this surface is not sensitive, or by being very out-of-focus at this surface; or the beam may enter through the part of the end window adjacent the phosphor screen and reflected back through the target, or through a window in the side of the tube. The mesh 5 may be employed as a stencil in the formation of the mosaic 4, the mesh being close to the target during evaporation of the photo emissive layer on to the target, and then being drawn away from the target; in this way the mesh is itself substantially non-photo emissive on the side facing the scanning light.