GB363343A - Improvements in or relating to luminescent gas discharge tubes - Google Patents

Abstract

363,343. Discharge lamps. CLAUDE NEON LIGHTS, Inc.; 41, East 42nd Street, New York, - U.S.A.-(Assignees of Beck, L. L.; 27, Stonleigh Park, Westfield, New Jersey, U.S.A.) June 5, 1930, No. 17437. Convention date, Feb. 28. [Class 39 (i).] A positivecolumn discharge lamp comprises a thermionic cathode and a principal filling of neon together with more than about 0À5 per cent of one or more of the gases argon, krypton, and xenon. A nickel, copper, or iron cathode 24, Fig. 1, is coated preferably on both sides with an alkaline earth compound. The coating may consist of an aqueous paste of barium oxide which is heated to 100‹ C. to reduce it to the suboxide. A heater is supported within the cathode by an insulating plug 25 and a conducting support 26, and is connected, as shown, in series with the cathode, so that heating is effected by the discharge current. Starting is facilitated by con- .necting the heater to an independent current source, e.g. the transformer 30. External electrodes 46, 47 may be connected to the internal electrodes, to a variable-voltage supply such as the transformer 42, or to a high-frequency supply. These electrodes may extend the whole length of, or be shorter than the tube, and they may be arranged at the centre or at the ends thereof. A glass having a high dielectric constant is preferably used for the tube. In a modification, a cylindrical cathode is mounted on a lead-in wire 56 by bands 51, 52, Fig. 3, connected to a member 54. Current is passed through a coiled heater 57, prior to starting, from a transformer 70, by closing a switch 66. By making connections, indicated by the dotted lines, the discharge current is adapted to pass through the heater. The pressure of the filling is preferably 1-10 mm. Dimensions of the tube and current densities are given. The Specification as open to inspection under Sect. 91 (3) (a) comprises also subject-matter which is contained in Specification 360,446. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specification 181,691, [Class 39 (i), Electric lamps, - Arc &c.].