GB187305A - Improvements in indirect lighting unit - Google Patents

Abstract

187,305. Stephens, A. J., (Dorey, W. A.). July 14, 1921. Reflectors; shades.-A device for semi-indirect lighting consists of an interior upwardly facing reflector 3 having double reflecting prisms 5 on the outer face, and superimposed on a separate shade 6 of approximately equal diameter, the reflector 3 being adapted to reflect part of the light rays from the light source 2 upwardly, and the shade 6 having on its surface a zone 8 of horizontal prisms to receive and direct light rays transmitted through the reflector and a zone of diffusing surface. The horizontal light directing prisms are arranged so as to reduce the shadows at the edge of the cone of light passing upwards from the light source, and the zone of diffusing surface is arranged so that the relative proportion of direct light below an angle of 60‹ with the nadir is greater than the quantity of light above this angle but below the horizontal. In one form the shade 6, Fig. 1, has on its lower portion a fluted interior surface 9 and a decorative outer surface 10. and the prisms 8 on its upper portion have faces 14 substantially vertical so that the light is refracted upwards, and faces 15 substantially parallel with the light rays falling on this surface. The reflector 3 is provided with a flange 16 which rests upon the flange 17 of the shade 6 so that the two flanges can be held together by a metal band or other suitable means. In another form the reflector 3, Fig. 2, is attached to the shade 6 by a screw and nut 19, and the opening between the upper ends of the two members is filled by a metal diaphragm 18, the lower surface of which is finished with a white diffusing coat. The lower inner surface 19 and outer surface 9 of the shade 6 are etched and the upper faces 15 of the prisms on its upper part 8 are reduced in slope as the lower edge of this surface 8 is approached. In other forms the shade 6 mav have colours or corrugations on its outer surface.