Patent ID: 7789549

Claim:
A surface light source comprising: a light guide plate including: a light exit plane; and a light entrance plane arranged on a periphery of the light exit plane; wherein the light exit plane and the light entrance plane are arranged to allow light incident on the light entrance plane to exit the light exit plane; the light entrance plane includes a plurality of end surfaces including at least one first end surface and at least one second end surface protruding in an external direction beyond the at least one first end surface in plan view of the light exit plane; and the at least one first end surface and the at least one second end surface are alternately arranged along the periphery of the light exit plane; and a plurality of light sources arranged to emit light onto the plurality of end surfaces; wherein the plurality of light sources are arranged out of alignment with a straight line along the periphery of the light exit plane; and the at least one first end surface and the at least one second end surface of the plurality of end surfaces are parallel or substantially parallel to each other.