GB413720A - Braun tube - Google Patents

Abstract

413,720. Cathode ray tubes. SCHLESINGER, K., 39, Friedrichstrasse, Friedrichshagen, Berlin. Dec. 21, 1932, No. 36159. Convention date, Dec. 24, 1931. [Class 39 (i).] The fluorescent screen 2 of a Braun tube is provided on its side facing the cathode with a metal coating 3 penetrated by electrons but reflecting light so that all the fluorescent light is directed towards the glass end-wall 1 of the tube to improve the brightness of the picture. The coating may be only just sufficiently thick to reflect the light and may be of silver, copper or tin, applied, for example, by the reduction of solutions of silver salts. The coating may be connected to a potential. The fluorescent layer 2 is applied to the wall 1 with a binder, or is sintered into the wall without using a binder, the glass being softened by heat. Specification 402,411 is referred to. The Specification as open to inspection under Sect. 91, comprises also the use of potash waterglass as the binder and also a cathode-ray tube with three anodes, two at a low potential, say 400 volts, and one at a much higher potential which may be 4000-8000 volts. The electron beam from a hot cathode 1, Fig. 3 (Cancelled), is concentrated by a Wehnelt cylinder 2 and is deflected, whilst travelling at low speed, by the plates 5, 6 between the two low-voltage anodes 3, 4, the metal coating 7 on the screen 8 forming the high-voltage anode. This subjectmatter does not appear in the Specification as accepted.