GB506143A - Improvements in iconoscopes - Google Patents

Abstract

506,143. Cathode-ray tubes. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. Oct. 10, 1938, No. 29356. Convention date, Oct. 12, 1937. [Class 39 (i)] In a television transmission tube the discrete photo-electric particles of the mosaic electrode are carried by a transparent insulator which is backed by a transparent continuous metal layer; this layer is made of platinum, rhodium or other metal of the platinum group ; the electrode may consist of a metal frame 5, Fig. 2, in which the mica insulator 6 is fixed. The platinum backing 7 may be applied in a vessel other than the cathode-ray tube by vaporization. In a modification the electrode is formed on the end wall of the envelope by first depositing, by vaporization or cathode disintegration, a layer 12, Fig. 3, of platinum to this is applied a layer 13 of insulation, which may be an alkaline earth borate or a suspension of glass of low melting temperature-glass enamel. This may be sintered. The silver, wall coating 17 for collecting secondaries is spaced from the platinum layer 12, a lead 16 from the latter passing through the wall. The signals may be taken from the resistance 20 connected to the collector layer 17. The photo-electric particles may be separated from the insulating layer by an aluminium braking layer as described in Specification 496,018. It is stated that some of the emitted photo electrons may pass through the insulating layer 13 to the electrode 12 and therefore not interfere with the secondaries emitted due to scanning, and from which the signals are obtained. The mosaic may be inclined within the tube and images thrown thereon from both sides.