Patent ID: 6749313
Filing Date: 2004-06-15
Classification: F21V,F21Y,G02B

Abstract:
A plate-type luminaire, comprising:a prism plate of light transmitting material, the prism plate having a smooth front plate surface and having an opposite second prism surface, the second prism surface comprising a plurality of parallel longitudinally extending ribs alternating with and defining grooves between adjacent ribs, and the ribs extending in a longitudinal direction along the plate; a cover plate comprised of light transmitting material and having a smooth third plate surface resting on the second prism surface of the prism plate, the cover plate having an opposite fourth surface away from the prism plate; an optical-waveguide plate of light transmitting material and having a fifth surface shaped to the smooth first surface of the prism plate and resting on the smooth first surface of the prism plate and having an opposite sixth surface away from the prism plate; the optical-waveguide plate having an end surface at an edge thereof adapted for enabling introduction of light into the optical waveguide plate; all of the prism plate, cover plate and optical waveguide plates are adapted for transmitting light from the optical waveguide plate, through the prism plate and from the prism plate through the cover plate and into a space outside the fourth surface of the cover plate; the prism plate, the cover plate and the optical waveguide plate are located respectively above one another with respective surfaces resting on each other; the plates all being continuously curved in the same direction of curvature and transversely to the longitudinal direction of the longitudinal ribs on the prism plate and over most of the widths of the plates, wherein the longitudinal ribs on the prism plate are located on the inside of the arc of curvature of the prism plate.