Surface light source device and apparatus using the same

摘要

A surface light source device for preventing the coloring phenomenon in the proximity of a spot light source of a light guide plate making up the surface light source device is disclosed. A spot light source of LED or the like is arranged at an edge of the light guide plate. A multiplicity of deflection patterns having a triangular cross section are arranged on the surface of the light guide plate opposite to the light exiting surface. The light entering the light guide plate are reflected on the deflection patterns and exit from the light exiting surface. The deflection patterns including a plurality of types of deflection patterns having different heights are arranged randomly.