Patent ID: 7708444

Claim:
A surface light source device comprising: a casing having an opening; a primary reflective part provided at a base of said casing in contrast to said opening; a plurality of dot light sources provided at a side of said casing base; and a light guiding plate provided on said primary reflective part located inside said casing and transmitting light to said opening from said dot light sources; wherein said light guiding plate is provided with a plurality of primary holes arranged in a row and perpendicular to a base of the light guiding plate in such a manner as to locate each said dot light source within said plurality of primary holes, and said light guiding plate comprises a plurality of auxiliary light source diffusing means which diffuses reflection from said dot light sources, said plurality of auxiliary light source diffusing means being located between any two of the dot light sources which are adjacent to each other and each of said auxiliary light source diffusing means is include a center located only at a middle point on a line connecting a center point of any two of said adjacent dot light sources, the auxiliary light source diffusing means not overlapping said plurality of primary holes in a direction perpendicular to the base of the light guide plate.