GB335617A - Improvements in or relating to electric lamps - Google Patents

Abstract

335,617. Dicker, S. G. S., (Naamlooze Vennootschap Philips' Gloeilampenfabrieken). June 29, 1929. Bulbs; multiple-filament lamps.-In an electric lamp comprising at least two incandescent bodies of which at least one is partly surrounded by a screen, the part of the bulb illuminated by the screened body 11, Figs. 1 and 5, is coloured, either entirely or partly, so that a beam comprising a fog-penetrating coloured or substantially coloured light is produced, whereas the beam radiated by the other incandescent bodv or bodies contains but little coloured light. The two incandescent bodies 11, 12 are so mounted inside the bulb 10 that the body 11 is located in the axis of the lamp and the body 12 intersects the axis. As shown, one half of the bulb is coloured yellow over two spaced areas 13, 14 the bright strip 15 between the coloured areas being so arranged that its longitudinal axis lies in a plane normal to the longitudinal axis of the lamp, the point of intersection of this plane with the axis of the lamp being near to the incandescent body 12. The lamp is adapted to be mounted within a parabolic reflector, with the body 12 at the focus thereof. The bulb is preferably coloured by surrounding it by a template or stencil and spraying with lacquer made from material known under the registered Trade Mark '' Bakelite," after which it is heated. A yellow layer may be obtained by burning-in silver oxide.