Patent ID: 8801195

Claim:
A projector comprising: an illumination system having a light source, a light shield unit that shields a portion of a light emitted from the light source, and a drive mechanism which drives the light shield unit; and a light modulation device illuminated by an illumination light received from the illumination system, wherein the light shield unit driven by the drive mechanism rotates around a predetermined rotation axis to change a size of a light shield area, the light shield unit having a leading edge defining a boundary between the light shield area and a non light shield area during the rotation, the leading edge having a contour defined by a plurality of first edges and a second edge disposed between the first edges, the second edge configured to be contoured toward the light source and projecting away from the first edges during rotation of the light shield unit, a reference plane contains a center axis of the light emitted from the light source and extends in parallel with the rotation axis, and a difference between a maximum distance from the first edges to the reference plane and a maximum distance from the second edge to the reference plane gradually and constantly decreases as the light shield area gradually increases by rotation of the light shield unit toward a fully closed condition, and when the light shield unit is in the fully closed condition, the maximum distance from the first edges to the reference plane and the maximum distance from the second edge to the reference plane become equivalent to each other.