GB491050A - Cathode-ray tubes, especially for television - Google Patents

Abstract

491,050. Cathode - ray tubes. MICHAELIS, E. Aug. 17, 1937, No. 22564. Convention date, Aug. 28, 1936. [Class 39 (i)] The electrodes constituting the lens system of a cathode-ray tube are formed by so shaping a body of insulating material as to form surfaces which are of the configuration, extent and disposition required for the system and then metallizing the surfaces so as tc form the desired electrodes. The insulating body A of glass or ceramic material is formed to the desired shape and the surfaces B, C, D are metallized by spraying, plating &c. to form a controlling cylinder and a first and second anode. In a modification, a number of parts may be shaped and metallized and are then formed into a single unit. The metal coating may be of such a nature as to act as a getter. The Specification as open to inspection under Sect. 91 comprises also a mushroom-shaped cathode made of insulating material such as quartz, porcelain or steatite, with the mushroom head made as thin as possible and provided with metal plate for the emissive material. The emission from the undersides of the mushroom head may be reflected in the forward direction from surfaces which may be secondary electron emitting. Another form of cathode described, consists of a cylinder or prism of insulating material with a central longitudinal heating filament and oxide coated on one or more flat faces. This subject-matter does not appear in the Specification as accepted.