GB632807A - Improvements in luminairs - Google Patents

Abstract

632,807. Luminairs. HOLOPHANE, Ltd. (Holophane Co., Inc.). Feb. 10, 1947, No. 3862. [Classes 75(ii) and 75(iv)] A light transmitting reflector for an elongated light source such as a fluorescent lamp extends upwardly from the level of the bottom of the light source to intercept low angled upwardly directed light and comprises vertical totally reflecting prisms and horizontally extending refracting prisms arranged to elevate both the transmitted and the reflected light. Two concave prismatic reflector plates 13 supported by a fixture 10 intercept upwardly directed light from fluorescent lamps 11 and a lens plate 12 having longitudinal prisms is disposed beneath the lamps to refract downwardly directed light toward the nadir. The reflector plates 13 are provided with vertical totally reflecting external prisms 16 and with upwardly thickening horizontal prisms 17 which may be either on the inside or outside surfaces of the reflectors. The prisms 17 refract the light so that a transmitted ray such as 18b is directed at a higher angle than the corresponding incident ray 18 and the reflecting prisms 16 return the major portion of the light into the luminair to be refracted across the vertical axis of the luminair by the lens plate 12. The sides of the reflecting prisms 16 may be outwardly concave meeting at 90 degrees as shown in Fig. 5 so that incident rays 32-34 are reflected as rays 32d-34d the divergence of which is the same as the convergence of the incident rays.