LINEAR LIGHTING EQUIPMENT

摘要

PURPOSE:To obtain bright linear lighting close to parallel light by designing a plane waveguide so that the refractive index increases in the thickness direction of a plate toward the center and the gradient of the refractive index distribution is steep toward the traveling direction of light. CONSTITUTION:The tube internal wall of an aperture type fluorescent lamp 1 is coated with a reflecting film and a fluorescent body one over the other except part of the wall and emitted light is reflected repeatedly by the tube internal surface and emitted out through an aperture part. A reflecting plate 2 has a higher reflection factor (n) on the side of the fluorescent lamp and the plane waveguide 3 increases in refractive index (n) in the thickness direction of the plate toward the center and varies in the gradient of the refractive index distribution in the traveling direction of light. The refractive index of the plane waveguide 3 is so distributed that the refractive index of the center of thickness is held at an incidence direction entirely in the thickness direction and the gradient of the refractive index distribution becomes steep from the incident end to the projection end. Incident light enters a convergent waveguide mode. The light is convergent on the center of thickness by the variation in refractive index distribution and converted from a high-order mode to a low-order mode gradually and becomes nearly parallel light on the projection end surface.