GB467820A - Improvements in or relating to electric discharge lamps - Google Patents

Abstract

467,820. Discharge lamps. GENERAL ELECTRIC CO., Ltd. (Patent-Treuhand-Ges. f³r Elektrische Gl³hlampen) Dec. 10, 1935, Nos. 34194/35 and 4271/36. [Class 39 (i)] [Also in Group XVIII] A lamp is adapted to operate on a predetermined sinusoidal voltage, is filled with a mixture of gases or vapours the 'components of which have ionisation potentials which are substantially different and is so asymmetrical that, in operation, so much electrophoresis occurs that both of the components emit light, one in one part of the lamp and the other in another part. A lamp may have a bore of 7 mms., thermionic electrodes of different emitting power and a filling which consists of helium at 6'7 7 mms. and argon at 0À3 mms. To produce white light the filling may consist of mercury and neon at 2 mms. ; sodium may be added so that a mercury discharge is located between the neon and sodium discharges. The part of the tube in which the mercury discharge occurs may be coated internally with zinc silicate. The tube may be surrounded by a diffusing envelope. The lamp may comprise two L-shaped limbs 1, 2 which are joined by a narrow tube and are provided at their upper ends with large electrode chambers in which are arranged a thermionic electrode of low work function and an electrode of high work function respectively. Red neon light is emitted from the limb 1 and blue mercury light from limb 2. The limbs are separated by an opaque screen 10 and a trough 9 with a white or green internal surface, is provided so that the red limb is seen on a background of blue light. The amount of mercury should be small so that it is all evaporated or, alternatively, it is confined in a porous chamber. In another form, the asymmetry of the tube may be produced by earthing both the secondary of the supply transformer and a suitable point of the tube. A starting electrode may be provided. Specifications 247,180, [Class 39 (i)], 415,111,415,113,424,322, and 449,031 are referred to. Reference has been directed by the Comptroller to Specification 424,322.