Patent ID: 8317386

Claim:
A planar illumination device, comprising: a laser light source for emitting a laser light; a light guide plate including a light incident end surface and a first principal surface, for guiding the laser light having entered through the light incident end surface to be outputted from the first principal surface; an optical element which forms the laser light into a substantially parallel light in a thickness-wise direction of the light guide plate; a light diffusing unit which diffuses the laser light in a direction orthogonal to the thickness-wise direction of the light guide plate; and a light deflecting unit which deflects the laser light having passed through the optical element and the light diffusing element in the thickness-wise direction of the light guide plate, wherein the light deflecting unit deflects the laser light in the thickness-wise direction of the light guide plate, after the laser light is shaped in a direction of the light incident end surface of the light guide plate by the optical element and the diffusing element, wherein the light deflecting unit includes a plurality of deflectors arranged on the first principal surface of the light guide plate or a second principal surface of the light guide plate facing the first principal surface, wherein the plurality of deflectors deflects the laser light incident on the light guide plate in the thickness-wise direction of the light guide plate using an optical phenomenon of at least one of reflection, scattering, refraction and diffraction, and wherein a density of deflectors of the plurality of deflectors is higher in a vicinity of the light incident end surface of the light guide plate than in other portions of the light guide plate.