GB593760A - Improvements in and relating to electric discharge lamps - Google Patents

Abstract

593,760. Discharge lamps. GENERAL ELECTRIC CO., Ltd., BREADNER, R. L., JENKINS, H. G., and SIMMS, C. H. March 21, 1945, No. 7158. [Class 39 (i)] In an electric discharge lamp of the type comprising two vitreous, e.g. glass components 10, 11, Fig. 2, sealed together, at least one of which has one or more upstanding ridges 12 so as to define a discharge passage between them, and in which the upstanding ridge or the outermost of the ridges merges into an outer wall 16 forming a boundary of the discharge passage so that this wall is effectively of non-uniform width, the crests of the ridge or ridges and the outer wall 16 lie close to or abut the other component 11, but are not sealed thereto, and a flange 20 of substantially uniform width is provided on at least one of the components outside or beyond the outer wall 16 and is sealed to the other component 11 so as to form a vacuum-tight closure to the discharge passage. Both components may be ridged, Fig. 2, the ridges and hence the discharge passage being of spiral form, in which case both the components 10, 11 are provided with a flange 20, 21, the flanges being sealed together to form the vacuum-tight closure. The surfaces of the flanges 20, 21 are preferably of substantially the same width where they are sealed together. Tubulations 22, 23 are provided in which the' ..electrodes (not shown) are mounted on pins 24, 25. The inside of the walls of the spiral discharge passage may be coated with a fluorescent powder. An exhaust tube 26 is provided. Alternatively, only one component may be ridged, in which case the other component may be a flat disc and the flange is provided only on the ridged component, Fig. 4 (not shown). The discharge passage is again of spiral form. The flange may be sealed to the upper surface of the disc or may extend over the edge of the disc and be sealed to this edge. In another form, Fig. 5 (not shown), the lamp comprises a ridged inner component and a plain unridged outer cylindrical component so that the discharge passage is of helical shape. The outer component may alternatively be of frustoconical shape. The Provisional Specification refers to an embodiment similar to that shown in Fig. 2 in which the ridges of the two components are of spiral shape and merge into their respective outer walls after approximately a quarter of a turn, and to an embodiment in which only one component is ridged, the unridged component being of domed shape. It also states that the invention may be applied to lamps of multistart spiral and zig-zag form.