Patent ID: 8911133

Claim:
A planar light source device comprising: a main body case that surrounds the periphery of a gap between a pair of optical reflection plates disposed to face each other with side plates; and a plurality of point light sources arranged at predetermined intervals on at least one side plate of the main body case, the planar light source device allowing light from the point light sources to be transmitted through at least one of the pair of optical reflection plates and emitted to an outside, at least one of the pair of optical reflection plates including a light blocking region that blocks light from the point light sources on the point light sources side, and a light transmission region that does not allow the light from the point light sources to be directly transmitted but allows reflection light reflected between the optical reflection plates to be transmitted, and is aligned so that transmissivity increases as the distance from the light blocking region increases, and luminance is substantially uniform on a surface of the optical reflection plate, the light blocking region and the light transmission region are separated from each other, and that a first distance from the light blocking region to the optical reflection plate opposed thereto is half of a second distance from the light transmission region to the optical reflection plate opposed to the light transmission region.