GB581935A - Process and apparatus for producing a coating of discrete metallic particles particularly the mosaic surface of the target of an electron camera tube - Google Patents

Abstract

581,935. Canal ray tubes ; depositing substances by electric discharges. WESTERN ELECTRIC CO., Inc. March 14, 1944, No. 4773. Convention date, April 29, 1943. [Class 39 (i)] In the production of a surface having a coating of discrete metal particles, such as the mosaic electrode of a television apparatus, a beam of the ions of the metal is scanned successively over the elemental areas of the surface by electromagnetic or electrostatic deflecting fields. When the surface is for television purposes, the metal may be photosensitive, such as one of the group of alkali or alkaline-earth metals, or a metal such as magnesium which is subsequently sensitized. The beam of ions is produced by evaporating a pellet 50 of the metal in an evacuated tube 11, which may be connected to the transmitting tube 10, the target 14 of which is to be formed, and which forms the negative electrode in a circuit including the anode 41, focusing electrodes 42, 43, deflecting coils 16, 17 and make- and-break contacts 45, 46. In the arrangement shown, a magnetic Held 53 or its equivalent electrostatic field directs the beam to the target. After preparation, the tube 11 is severed from the tube 10. Specification 381,606 is referred to. In an alternative arrangement, Fig. 3 (not shown), the ion beam producing tube is disposed in line with the target electrode and the field 53 dispensed with.