Lens light guide plate and surface light equipment using the same

Abstract

A non-light-diffusive light guide plate, the light-diffusing properties being not imparted thereto by means of printing or the like, has a light-emerging surface provided with a condenser lens which is produced by arranging columnar lenses having convex cross-sections so that their ridge lines will be parallel with each other, and, at the same time, vertical to the side end surface, the light-entering surface of the light guide plate. The shape of the cross-section of the light guide plate is such that the thickness becomes smaller as the distance from the side end surface on the light-source side becomes longer and that the inclination of the line corresponding to the light-reflecting surface which is opposed to the light-emerging surface is steeper on the light-source side than on the non-light-source side. A surface light equipment comprises, as a means for raising light which emerges from the light-emerging surface of the light guide plate to the direction of the normal of the light-emerging surface, a lens film on which columnar lenses having triangular cross-sections are arranged so that their ridge lines will be parallel with each other. This lens film is arranged so that the ridge lines of the columnar lenses will be parallel with the side end surface serving as the light-entering surface and that the vertexes of the triangles will face the light guide plate.