Patent ID: 7004612

Claim:
A planar light source device, which comprises a light guide having at least one side end serving as a light incident side and having one surface serving as a light-emitting side, a light source disposed in the vicinity of the side end of the light guide, and a light reflector disposed on the other side opposite to the light-emitting side, wherein the light guide is essentially formed of a polyolefin resin, the light reflector is also essentially formed of a polyolefin resin, and when a piece of the light reflector having a face size of 1.5 cm×1.5 cm is prepared, and it is pressed against the surface of the light guide with its reflective face being in contact with the surface of the light guide under a load of 135 g/cm 2 thereto, and, in that condition, when it is reciprocated 10 times on the surface of the light guide to a width of 5 cm every time at a speed of 2.5 cm/sec, then the surface of the light guide is not substantially scratched by it.