GB422708A - Cathode ray tube - Google Patents

Abstract

422,708. Cathode-ray tubes. RADIOAKT.-GES. D. S. LOEWE, 10, Wiesenweg, Steglitz, and SCHLESINGER, K., 39, Fried.- richstrasse, Friedrichshagen, both in Berlin. July 17, 1933, No. 20110. Convention date, July 18, 1932. [Class 39 (i)] In Braun tubes with means for controlling the intensity of the ray, two pairs 2, 12 of deflecting plates and a fluorescent screen 7, apertured metal diaphragms 1, 6 are placed near the deflecting plates, between the pair 2 and the cathode 17 and between the pairs 2, 12 to prevent the influence of the edge fields of the plates on the speed of the ray and the influence of the pairs 2, 12 on each other. A further metal diaphragm 16 may be arranged between the plates 12 and the screen 7 to intercept return electrons produced at or reflected from the screen 7. The apertures 18, 19, in the diaphragms 1, 6, 16 are as small as possible without intercepting the ray, the aperture 18 being circular and of diameter less than the distance between the deflecting plates and the apertures 19 being rectangular. The diaphragm 1 may be the anode of the tube. The diaphragm 16 may be connected to the other diaphragms by a sleeve 9 intercepting return electrons or may be at a higher potential. The screen 7 may be metallized and at a high potential. The Specification as open to inspection under Sect. 91 comprises also the use as a screen of a metal coating or getter deposit on the wall of the tube and raised to or above the potential of the anode 1 and the biassing of the pairs 2, 12 negatively relatively to the diaphragm 6, and discusses the effect of return electrons on the sensitivity of the deflecting plates. This subject-matter does not appear in the Specification as accepted.