GB400038A - Improvements in and relating to light mixing apparatus - Google Patents

Abstract

400,038. Light-mixing apparatus. HOLOPHANE, Ltd., Elverton Street, Vincent Square, London.-(Assignees of Dorey, W. A. and Dixon, H. M. ; Newark, Ohio, U.S.A.) Jan. 23, 1933, No. 2147. Convention date, July 1, 1932. [Classes 75 (ii) and 75 (iv).] Light reflected by trough-shaped r eflectors ; different illuminants for separate or simultaneous use.-A lightmixing apparatus comprises two or more longitudinal light sources each disposed substantially along a focal line of a cylindrical reflector of substantially elliptical contour, and a longitudinal light-emitting aperture. The light sources may be different in colour or other operating characteristics and they may comprise rectilinear filament bulbs, mercury vapour, neon, or other electric discharge tubes, or linearly arranged and closely spaced substantially point sources. The reflector may be made of prismatic or silvered glass, polished metal, or other specular or slightly matte finished material, and it may be slightly corrugated or rippled. The light may be emitted directly by the reflector but the aperture is preferably closed by a flat or trough-shaped glass plate which may be clear, diffusing, ribbed, or prismatic. In the form shown in Fig. 2, longitudinal light sources are arranged substantially along the focal lines 11, 12 of a semielliptical cylindrical reflector 10 which is provided at its edges with cylindrical reflectors 15 of modified section and is fitted with a rectangular prismatic glass plate 16 disposed parallel to the major axis of the reflector 10. In a modification, Fig. 5 (not shown), the glass plate is at right-angles to the major axis. Fig. 3 shows a cylindrical reflector 22 of circular section arranged concentrically with the focal line 24 of a semi-elliptical cylindrical reflector 21, and a glass plate 25 disposed between the reflector 22 and a cylindrical reflector 23 of modified section. In a further modification, Fig. 4 (not shown), a pair of such circular and elliptical cylindrical reflectors are combined and have a common focal line along which a longitudinal light source may or may not be arranged.