GB740751A - Improvements relating to the mounting of meshes in electric discharge devices - Google Patents

Abstract

740,751. Discharge apparatus. ELECTRIC & MUSICAL INDUSTRIES, Ltd. May 8, 1953 [May 8, 1952], No. 13475/52. Class 39 (1). A flat metal mesh such as for use first as a stencil for depositing the mosaic target of a television pick-up tube and then as a stabilizing electrode in front of the mosaic target, is mounted in a frame for movement from one plane to another parallel plane; it is held by spring pressure in one plane and then dislodged and moved to the other plane by a light force where it is locked positively by the holding means operating as an automatic catch. The mesh 10 is secured across a frame 9, Fig. 1, which is mounted on a second frame 2. Projections 11 of the frame 9 ride in guide-ways 21 Fig. 3, in the frame 2. Arms 13 pivoted at 14 hold, under pressure of a spring 16, the projections 11 and consequently the mesh in the first position. Subsequently the mesh is dislodged so that the projections 11 are moved past the ends of the arms 13 which then prevent their return. The mesh frame 9 is then locked against flanges 6 on the frame 2, Fig. 1. The mosaic target is deposited on a dielectric sheet 3 applied to the end wall 1 of the tube with the interposition of a conductive film 4 to form the signal plate. In the deposition step by evaporation through the mesh, the mesh is pulled into intimate contact with the dielectric sheet 3 by electrostatic attraction. The pick-up tube may be of the type operated with cathode potential stabilization. Specifications 600,520 and 657,666 are referred to.