Patent ID: 7322729

Claim:
A light guide unit having at least one radiation direction in a direction substantially perpendicular to an optical axis of a light source, comprising: a first reflecting portion that is configured to face the light source and includes a plurality of reflecting surfaces configured to reflect light incident thereon toward a plurality of directions substantially perpendicular to the optical axis; a forward reflecting portion that is configured to reflect light that was reflected approximately toward the radiation direction by the first reflecting portion, toward the radiation direction as a forward direction; a backward reflecting portion that is configured to reflect light that was reflected toward a backward direction opposite to the radiation direction by the first reflecting portion, substantially toward the radiation direction; and a radiating portion having at least one substantially rectangular radiating surface having a width in the optical axis direction that is smaller than a width perpendicular to the optical axis direction, wherein light from the forward reflecting portion and light from the backward reflecting portion are directed toward the radiation direction so that the radiating portion radiates the light from substantially its entire surface.