Patent ID: 8500308

Claim:
A light source device comprising: a highly directional point light source; a reflective hood that has a bottom portion on which the point light source is secured and a pair of side reflective portions opposing to each other extending outward from opposing sides of the bottom portion and having open end portions, an inner space of a specific volume defined by the bottom portion and the pair of side reflective portions inside, and an inner wall surface formed of a reflective surface; and a pair of first and second polarizing reflective plates that polarize irradiation light from the point light source to a specific direction, wherein the first and the second polarizing reflective plates are each made of a plate material having a specific length and width and a high reflection rate on front and rear surfaces, at least one such point light source is secured on the bottom portion of the reflective hood, and the first and the second polarizing reflective plates are tilted by a specific angle α with respect to an optical axis passing through the 0° direction angle of the point light source so that a specific gap is provided between the first and the second polarizing reflective plates and the reflective surface of the reflective hood, and a specific gap is provided between the first and the second polarizing reflective plates with the optical axis in between in such a manner that the gap is larger at a portion closer to the point light source and the gap is smaller at a portion away from the point light source.