GB439266A - Improvements in electric incandescent lamps - Google Patents

Abstract

439,266. Electric incandescent lamps. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, Emmasingel, Eindhoven, Holland. Jan. 5, 1935, No. 442. Convention date, March 26, 1934. [Class 39 (ii)] An electric incandescent lamp bulb with a gas filling consisting wholly or mainly of crypton, xenon, or both of these gases, and a volume which, measured in cubic centimetres is smaller than W + 25, where W is the wattage of the lamp, is secured to the lamp cap 3 by means of an intermediate connecting member 2 which either consists of insulating material or is insulated from the cap, the diameter of the member at the point at which it is secured to the bulb 1 being either less than or substantially equal to that of the cap, thereby minimizing the quantity of light absorbed by the intermediate member. The intermediate member 2 may be cylindrical, as shown, or a contraction may be provided at its junction with the bulb. Alternatively the member may be in the form of a truncated cone, the junction with the bulb being at the smaller end. The length of the member may be such that the light centre length of the lamp is substantially the same as in a normal sized lamp of the same wattage. Preferably the filament 10 is wound as a coiled coil, and the leading-in wires 5, 7 each comprise a fuse wire. The interior of the cap may also be insulated. In a modification the bottom of the cap is covered by a thick insulating layer.