| 摘要 |
420,067. Cathode-ray tubes. HUDEC, E., 17, Potsdamerstrasse, Sudende, Berlin. Feb. 22, 1933, No. 5470. Convention date, Feb. 23, 1932. [Class 39 (i)] The brightness of the fluorescent spot of a Braun tube for television &c. is modulated by an electrostatic field which controls the number oi electrons leaving the cathode and which, in front of the cathode in the direction of the anode, is parallel to the axis of the beam, the beam being then concentrated by a second electrostatic field converging from a positive electrode As to a more positive electrode Ak. The controlling field is formed between the cathode K, the Wehnelt cylinder W and the electrode As, the cathode projecting through a disc inside the cylinder W and the modulating voltages being applied to the cylinder W or to the electrode As. The electrode As is conically or spherically concave on the side facing the electrode Ak. The cathode may be an annular filament. The potential difference between the electrodes K, As is one-tenth that between the electrodes K, Ak. The potentials of the electrodes W and As are adjusted independently of the potential of the electrode Ak. Specification 271,131, [Class 39 (i)], is referred to. |
