GB481445A - Braun tube - Google Patents

Abstract

481,445. Cathode-ray tubes. RADIOAKT.-GES. D. S. LOEWE. Sept. 10, 1936, No. 24681. Convention date, Sept. 25, 1935. [Class 39 (i)] In a Braun tube 1 in which the end of the bulb serving as a base for the luminous screen presents a flat surface 2 and the mechanical strength of the tube is ensured by distributing the pressure on the end in one or more antechambers 3, the innermost antechamber is formed from a bowl-shaped member having part of its lateral wall 4 slipped over a part of the lateral wall of the tube. The antechamber may be fused or cemented to the tube. The intermediate pressure may, with a single antechamber, be 200 mms.; this may be obtained by pumping or by evaporation of a getter. If a getter is used, obscuration of the image by reflecting layers of getter metal is avoided, for example by placing the getter in a side-chamber, Fig. 2 (not shown), or in a bulge of the antechamber screened off by a piece of mica, Fig. 3 (not shown). A manometer permanently attached to the ante-chamber may give a continuous indication of the pressure therein. Interfering reflections may be avoided by inclining the surface of the ante-chamber, Fig. 3 (not shown), or by making the surface concave to'the outside, Fig. 4 (not shown). If a number of antechambers are used they may be given flat end faces. Specification. 461,334 is referred to.