GB700829A - Improvements in illuminating systems for signs or display panels - Google Patents

Abstract

700,829. Signs. FORGES ET ATELIERS. DE CONSTRUCTIONS ELECTRIQUES DE JEUMONT. Sept. 18, 1951 [Oct. 4, 1950], No. 21851/51. Class 3(2) [Also in Groups XI, XX and XXXVIII] In an illustrating system, including transmission of concentrated light along transparent rods and its distribution upon signs or panels, the optical devices for concentrating and distributing the light are each composed of a single member made of transparent material and shaped, in the case of the light concentrating device, as a refracting lens and an internal reflector and. in the case of the light distributer as a refracting lens and diffusing surface. The device for concentrating the light from a source L into the end of a transparent light transmitting rod T consists of a transparent body of revolution having the central parts A1, A2 of its end surfaces shaped to form a double convex lens, the annular outer part of one end being spherical and concentric with the source, the annular outer part at the other end being part conical. Rays such as r which pass through the annular spherical part of the end surface are totally reflected by the conoidal side surface of the body and pass outwardly through the annular conical end surface to converge on a point L' inside the transmitting rod T. Rays passing through the central part of the device also converge on the point L<SP>1</SP>. The device for distributing the light from the remote end of the transmitting rod T consists of a frusto-conical transparent body D, the smaller end F<SP>1</SP> of which is in the form of a re-entrant cone having a curved generatrix and refracts light from the rod T on to the larger circular end P which is frosted to diffuse the light. The larger end serves as a display screen and may include suitable signs or inscriptions. Alternatively the distributer may be of prismatic shape, the diffusion surface P being rectangular and the admission surface being shaped as two tangent cylindrical surfaces. The system may include two or more rods which convey light of different colours to a single distributer from selectively operated light sources each having a concentrating device, the distributer being similar to the distributer D<SP>1</SP> but instead of the admission surface being shaped as a re-entrant cone, it has two or more concave surfaces. A transmitting rod with a single exit end and branched to provide two or more entry ends may be used.