GB433787A - Improvements in and relating to illuminating devices - Google Patents

Abstract

433,787. Electric incandescent lamp bulbs and filaments; lenses and reflectors. RIVIER, L., O'Oche, Jouxtens, MÚzery, Vaud, Switzerland. Feb. 19, 1934, No. 5393. Convention date, Feb. 22, 1933. [Classes 39 (ii), 75 (ii), and 75 (iv)] An illuminating device comprises two or more spaced light sources disposed at equal distances from, and in a plane perpendicular to, the central axis of a reflector in the shape of a surface of revolution, the light sources being so disposed between the axis and the surface of the reflector that those portions of the surface which are nearest each light source reflect each a luminous flux containing parallel rays and having a maximum of intensity in the direction of the parallel beam. As shown, a spherical bulb 1 contains two light sources 2 formed of coiled portions of a single filament. The lower half 1<a> of the bulb is silvered and the filaments 2 form parallel beams a, b with the nearest portions of the bulb. A modification having four coiled filament portions is described. The Specification as open to inspection under Sect. 91 comprises also the following subject-matter : (1) An annular filament is arranged in a lamp-bulb having a hemispherical reflecting portion. A cone of parallel rays is obtained which may be converted into a plane beam by a prismatic refracting ring 8, Fig. 9 (Cancelled). (ii) A lamp bulb has an elliptical reflecting portion and a filament extending along the axis, to produce a cone of parallel rays, Fig. 10 (Cancelled) (not shown) ; or a tubular lamp within an elliptical reflector may be similarly used. (iii) One or more light sources may be rotated about the axis of a reflector to increase the illuminated area. (iv) As shown in Fig. 11 (Cancelled), a lamp bulb has two ellipsoidal reflecting portions 27, 29 having a coincident focus 25 and other foci 26, 31 respectively. The filament extends from 25 halfway to 31. The arrangement is said to produce a hollow cone of parallel rays, which is' refracted by a glass cone 35 to form a parallel beam. The portion 29 is depressed to permit passage of the rays normally through the envelope. This subject-matter does not appear in the Specification as accepted.