GB397719A - Improvements in electric lamps - Google Patents

Abstract

397,719. Electric incandescent lamps. RIVIER, L., Jouxtens - Mezery, near Lausanne, Switzerland. Nov. 16, 1932, No. 32376. Convention date, Nov. 16, 1931. [Class 39 (ii).] In an electric lamp of the type having the source of radiant energy placed in a bulb a portion of which is transparent and another portion forms an ellipsoidal reflector, the bulb having a shape such that the focal point to which the reflected rays are concentrated is situated outside the bulb, the transparent portion projects into the interior of the reflecting portion and forms a cavity on the external surface of the bulb. As shown in the Figure, the filament 7 is placed at one of the foci 4 of the internal reflecting surface 15, 16 which constitutes a fragment of an ellipsoid the reflected rays being concentrated as shown at the other focus 6 which is outside the bulb, the spherical transparent portion 3 projecting into the interior of the reflecting surface. An opaque band 14 may be provided to join the reflecting and transparent surfaces. The concentration of light may be used for heating purposes to replace matches or other lighters. Alternatively, the lamp may be used in anti-glare vehicle headlamps by the utilization of a screen arranged with an edge passing through the focus 6 to intercept all rays on a certain side of the focus. A suitable reflecting surface may, alternatively, be arranged to reflect a maximum proportion of the light and this reflecting surface may be coloured to produce coloration of the light it reflects. Lamps of the type described may be employed for projection purposes. The Specification as open to inspection under Sect. 91 comprises also arrangements of the bulb in which the transparent portion does not project within the reflecting surface and also arrangements in which the focus at which the reflected rays are concentrated lies within the bulb. This subject-matter does not appear in the Specification as accepted.