Patent ID: 8564854

Claim:
A light guide body comprising: a prism formed surface provided opposite to a light emitting surface and having a longitudinally extending array of a plurality of prisms to allow light emitted from a light source to enter an end side of a light incident surface of the light guide body in the longitudinal direction and to be emitted from the longitudinally extending light emitting surface, wherein top surfaces and inclined surfaces of the prisms on a side opposite to the light source are configured, such that in a region of the light guide body on a light source side, the light traveling to the side opposite to the light source in the light guide body is sequentially reflected by the top surfaces and the inclined surfaces on the side opposite to the light source of the prisms, and is emitted from the light, emitting surface in a direction that approaches a direction orthogonal to the longitudinal direction of the light guide body, and wherein the prism formed surface has a configuration in which portions between adjacent prisms are positioned on a first reference surface, the first reference surface comprising a planar surface, the top surfaces of the prisms being positioned on a second reference surface, the top surfaces of the prisms positioned such that a distance from the first reference surface changes along the longitudinal direction of the light guide body, and the heights of the prisms, defined by a distance between the first reference surface and the second reference surface, changes according to a required illumination distribution property.