GB434919A - Improved mercury vapour lamp, more particularly for projection purposes - Google Patents

Abstract

434,919. Mercury - vapour lamps. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, Emmasingel, Eindhoven, Holland. Jan. 25, 1935, No. 2541. Convention date, Feb. 5, 1934. Drawings to Specification. [Class 39 (i)] A lamp, more particularly for projection purposes, comprises one or more fixed incandescent electrodes and a filling of mercury vapour which is unsaturated during normal operation, the consumption of energy per cm. of the discharge path exceeding 100 watts. The load depends upon the softening temperature, and the dimensions of the bulb. The electrodes preferably are located vertically one above the other but a magnetic field may be used to suppress the curvature of a horizontal discharge path. The lamp may be provided with two oxide-coated helically-wound electrodes which may be heated directly or indirectly or by the discharge. Glass is applied to the leading-in wires and is fused to the envelope which may consist of quartz or the material known under the Registered Trade Mark "Supremax." The filling of a lamp of which the Specification gives dimensions of the envelope and distances between the electrodes &c., consists of argon at 5 mm. pressure and 1 gme. of mercury. To obtain a uniform thermal distribution over the envelope, the distance between the lower electrode and its seal is smaller than that between the upper electrode and its seal. The lamp may be housed within an envelope containing gas at a pressure greater than atmospheric.