GB374007A - Improvements in electric discharge tubes - Google Patents

Abstract

374,007. Coating with metals ; treating metallic surfaces to produce a modified surface. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, 13D, Emmasingel, Eindhoven, Holland. Feb. 23, 1931, No. 5643. Convention date, Feb. 25, 1930. [Class 82 (ii).] A glow-discharge lamp has at least one electrode in which alkali metal is provided on a layer of alkali-metal oxide of the composition R2O in which R denotes an alkali metal. The lamp may comprise a ring-shaped metallic elec. trode 3 and a copper-plate electrode 5 which is coated with caesium oxide on one side and with aluminium oxide on the other side. The elec. trode is formed by introducing caesium into the lamp by evaporation from a chamber connected therewith, or by the method described in Specification 323,718, [Class 39 (i), Electric lamps, Arc &c.]. An excess of oxygen is then introduced to form caesium oxide of the composition Cs2O4 which is reduced at a temperature of 200‹ C. to Cs2O by the introduction of a further quantity of caesium. More caesium may be introduced to form the layer of pure metal if the second quantity of caesium is insufficient. In a modification, a calculated quantity of oxygen is introduced after the admission of caesium to form Cs2O directly. In a further modification, the copper plate is caused to adsorb water vapour which reacts with caesium to form Cs2O and hydrogen which is removed. Reference has been directed by the Comptroller to Specifications 362,346 and 362,347, [both in Group XL].