GB401727A - Cathode ray tube - Google Patents

Abstract

401,727. Cathode - ray tubes. ARDENNE, M. VON, 19, Jungfernstieg, Lichterfelde, and LOEWE, S., 10, Wiesenweg, Steglitz, both in Berlin. May 19, 1932, No. 14240. Convention date, May 23, 1931. [Class 39 (i).] In gas-filled cathode-ray tubes with a cathode 1 and an anode 5 producing only one cathode-ray which is deflected by plates 6, 7 or other means before reaching the fluorescent screen 10, the gas in the space traversed by the 'ray is ionized by an auxiliary discharge or other means independent of the main discharge. The ionization is sufficient to maintain the focusing of the ray for high and fluctuating rates of deflection, but is insufficient to neutralize the ray before it reaches the screen 10. The ionization may be produced by a glow discharge between electrodes 3, 4 or preferably electrodes 8, 9 or by an arc discharge between pointed electrodes or by radioactive substances in pockets on the wall of the tube or by thermionic electrodes. A thermionic electrode may act as the cathode 1 of the main discharge and also as the anode of the auxiliary discharge. The ionization should be as even as possible. A gas of low molecular weight such as hydrogen is preferred for the filling, the rapid diffusion of ions resulting in a large ionized area. A tungsten - thorinm or barium - alloy cathode may be used.