Patent ID: 7578607
Filing Date: 2009-08-25
Classification: G02B

Abstract:
1. A light source device comprising: a primary light source; a light guide having a light incident surface for receiving light emitted from the primary light source, guiding an incident light and having a light emitting surface for emitting a guided light; and a light deflector; the light deflector comprising: a light input surface for receiving incident light; and a light output surface for emitting incident light, wherein the light output surface is located on the opposite side to the light input surface, and the light input surface has a plurality of elongated prisms arranged in parallel to each other, each having a first prism face and a second prism face, and wherein the first prism face is a single planar surface, the second prism face is a non-single planar surface, a vertex split angle α of the first prison face which form each of the elongated prisms is 2 to 25 degrees while a vertex split angle β of the second prism face is 33 to 40 degrees, a difference (|α−β|) between the vertex split angle α and the vertex split angle β being 8 to 35 degrees, the first prism face is arranged to receive the incident light to introduce it into the light deflector, and the second prism face is arranged to reflect an introduced light toward the light output surface, wherein the light deflector is arranged with its light input surface located vis-à-vis the light emitting surface of the light guide, and wherein the light deflector is arranged with the first prism face of each of the elongated prisms located close to the primary light source and with the second prism face of each of the elongated prisms located remotely from the primary light source.