GB470496A - Television tube - Google Patents

Abstract

470,496. Cathode-ray tubes. RADIOAKT.-GES. D. S. LOEWE. Nov. 15, 1935, No. 31651. Convention date, Nov. 20, 1934. [Class 39 (i)] In television tubes with an aperture in a diaphragm 7, Fig. 1, electron-optically reproduced on the picture screen, the cathode-ray is concentrated on to this aperture by a preliminary concentrating system including a positively biassed electrode 5 which acts as a " suction anode ".between the diaphragm 7 and a Wehnelt cylinder 3 surrounding the cathode 1 and which is connected to means such as a potentiometer for adjusting its potential so as to control the preliminary concentration of the ray by varying the speed of the electron in the preliminary concentrating system. The cylinder 3 acts as a control grid with an aperture very close to the oxide spot on the cathode 1, which may be of the type described in Specification 455,084. The electrode 5 is an apertured plate very close to the grid 3 and is followed by a cylinder 6 which may be connected inside the tube to the cathode 1. The electrode 5 may serve additionally as a separate control electrode for temporarily blocking the cathode-ray in television systems in which the synchronizing signals are of the same type as signals for picture parts of maximum brightness. The cathode 1 may be electron-optically reproduced on the diaphragm 7 on a scale of 1 : 1 and the rays emerge from the diaphragm 7 with only a small divergence. The diaphragm 7 is connected to the final anode 9 and is reproduced on the picture screen by an electron-optical system 8, 9 as described in Specification 457,846. The grid 3 and cathode 1 are centred by a metal base S. Dimensions and voltages of the electrodes are specified. In a modified preliminary concentrating system, two ' cylindrical electrodes 6, 7<1>, Fig. 3, are provided between the electrodes 5, 7. The electrode 71 is longer and more positive than the electrode 6 and both may comprise metal or graphite coatings on an insulating tube 10 as described in Specification 466,188. The electrodes 6, 7<1> are connected respectively to the electrodes 5, 7, or the electrode 6 is insulated from the electrode 5. Specifications 432,485, 442,511, 452,650, 452,844, 453,270, and 461,235 also are referred to. The Specification as open to inspection under Sect. 91 comprises also other subject-matter described in Specification 466,188. This does not appear in the Specification as accepted.