Patent ID: 6805468
Filing Date: 2004-10-19
Classification: F21V,F21Y,G02B,Y10S

Abstract:
A surface light source device comprising:a thin rectangular light guide plate having a pair of major surfaces that are opposed to each other and a plurality of side surfaces that connect the pair of major surfaces, one of the major surfaces forming a light-emitting surface, the other major surface being provided with light reflecting means and one of the side surfaces forming a light incident surface; a light source assembly including a plurality of point light sources so as to be arranged along a longitudinal direction of the light incidence surface of the light guide plate; and a prism member disposed between the light source assembly and the light incidence surface, the prism member including a prism sheet consisting of a plurality of minute prisms that are arranged along an arrangement direction of the point light sources and that have a function of refracting light that is emitted from each of the point light sources and thereby inputting, to the light incidence surface, refracted light that is scattered to both sides in the longitudinal direction of the light incidence surface, the prism sheet being opposed to the point light sources, and the light incidence surface with air layers interposed in between, respectively.