GB994453A - Improvements in biquinary glow-discharge digit-indicator tubes - Google Patents

Abstract

994,453. Glow-discharge lamps. ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. Jan. 28, 1963 [Jan. 31, 1962], No. 3428/63. Heading H1D. A biquinery glow-discharge digit-indicator tube has a substantially cylindrical glass envelope 1 enclosing two groups of five digitcathodes separated by an apertured partition 11, 15, wherein the cathodes are arranged parallel to the longitudinal axis of the envelope, the partition extends across the tube so that longitudinally-extending edges of the partition approach closely the cylindrical wall of the envelope, the cathode assembly is positioned between substantially circular mica plates 5, 6 which are disposed at right-angles to the longitudinal axis of the tube and which also extend close to the envelope wall so that a separate compartment is formed for each cathode group, an anode 9 is positioned adjacent the outermost cathode of each group, the partition has a plurality of apertures which make the partition at least 75% transparent, the smallest dimension of the apertures being not more than <SP>1</SP>/ 80 th of the longitudinal height of a cathode, and the tube envelope contains a quantity of mercury. The anodes 9 preferably extend from adjacent the partition to adjacent the outermost cathode and are in the form of a wire grid fixed to supports, e.g. 28. The tube is filled with a rare gas, or a mixture of rare gases, e.g. neon and 0À25% argon, to a pressure of at least 70 mms. Hg., e.g. 100 mg. Hg. and the product of this pressure in mms. times the distance between adjacent cathodes is at least 40. The partition may be arranged eccentrically within the tube, disposed closer to the normal viewing position, with the odd numbered digits disposed in the front portion. The outside of the envelope bulb is preferably coated with a red lacquer layer. Specifications 994,454 and 994,455 are referred to.