GB387130A - Improvements in or relating to electric discharge tubes for generating ultra-violet rays - Google Patents

Abstract

387,130. Discharge lamps. HUMMEL, C., 34, Eisenacher Strasse, Berlin. Feb. 10, 1932, No. 3972. Convention date, Feb. 11, 1931. [Class 39 (i). A fluorescent substance which emits ultra-violet light under electronic bombardment is provided within a lamp having at least one independently heated activated electrode, e.g. on an electrode or on the walls of the bulb of quartz or the like. The bulb may be filled with a noble gas or a vapour. Each electrode may consist of a hot filament and a plate as shown in Fig. 2. The fluorescent substance may be made conductive by addition of suitable metal powder, or a network, or metal sulphides. A single electrode, Fig. 4, arranged so that there is a potential drop across neighbouring points of the helices 11, 12 may provide incandescent light in addition to an electron stream. The bulb may be partly covered with a reflector such as a metal film of chromium or magnalium. Suitable fluorescent materials are iron or mercury compounds, or yttrium, lanthanum, or gadolinium compounds, which may be mixed with sulphides, selenides, or oxides of the alkali or alkaline earth metals, or with boron compounds, or sulphides or zinc or aluminium. The Specification as open to inspection under Sect. 91 also comprises lamps having cold electrodes which may be grid shaped and having a filling of noble gas or mercury vapour at a pressure of one hundredth to several mms. This subject-matter does not appear in the Specification as accepted.