Patent ID: 8040458

Claim:
A planar illumination device for illuminating a liquid crystal display panel provided with a polarizing plate on a light incident side, comprising: a light source unit for emitting light having a specified polarization direction; and a light irradiating member for deflecting light emitted from the light source unit and irradiating the liquid crystal display panel with the deflected light, wherein the light irradiating member deflects the light emitted from the light source unit such that the polarization direction of the light emitted from the light source unit substantially coincides with a transmission axis direction of the polarizing plate of the liquid crystal display panel; and the light source unit includes either a first light source for emitting light having a polarization direction substantially orthogonal to a surface of the polarizing plate to be incident on the light irradiating member in the transmission axis direction of the polarizing plate or a second light source for emitting light having a polarization direction substantially parallel to the surface of the polarizing plate to be incident on the light irradiating member in a direction orthogonal to the transmission axis direction of the polarizing plate.