Patent ID: 7278772

Claim:
A spread illuminating apparatus comprising: at least one spot light source; and a light conductive plate which comprises: a light entrance end surface at which the spot light is disposed; a light reflection surface constituted by one major surface of the light conductive plate, on which a regular reflection mechanism is provided, the regular reflection mechanism including a plurality of paired inclined surfaces which extend in a direction substantially parallel relative to the light entrance end surface and which are arrayed in a direction substantially orthogonal relative to the light entrance end surface; and a light exit surface constituted by the other major surface of the light conductive plate, on which a plurality of ridges are provided, the ridges extending in the direction substantially orthogonal relative to the light entrance end surface, wherein: the plurality of ridges meander in a plane parallel to the light exit surface; the plurality of ridges meander in accordance with an identical periodic function; and the plurality of ridges are each shifted in phase from each other so as to be arranged non-parallel to any adjacent ridge.