Projector

A projector comprising:

• an illumination device including
• a light source device having an ellipsoidal reflector, a light emitting tube having a center of light emission near a first focus of the ellipsoidal reflector, and a collimator lens that makes the light emitted from the light emitting tube and reflected by the ellipsoidal reflector into a nearly parallel beam;
• a first lens array having plural first small lenses for dividing an illumination beam emitted from the light source device into plural partial beams;
• a second lens array having plural second small lenses corresponding to the plural first small lenses of the first lens array;
• and
• a superposition lens for superposing the partial beams emitted from the plural second small lenses in an area to be illuminated;
• an electro-optic modulator that modulates the illumination beam from the illumination device according to image information, each first small lens in the first lens array has a plane shape compressed in a direction which is either longitudinal or lateral direction so as to make the illumination beam emitted from the illuminating device into an illumination beam having such a sectional shape as to illuminate a part of an image forming area in the one direction in the image forming area of the electro-optic modulator, and to illuminate the whole of the image forming area in the other direction;
• a light cut-off member that is arranged in a position which is optically conjugate with the plural first small lenses and the elector-optic modulator between the illumination device and the electro-optic modulator, and has a predetermined opening part for adjusting the sectional shape of the illumination beam, the width along the one direction in the central portion in the other direction of the opening part is narrower than each width along the one direction at both ends in the other direction of the opening part;
• a rotating prism that is arranged on the electro-optic modulator side of the light cut-off member, and scans the illumination beam from the light cut-off member, in synchronization with a frame rate of the electro-optic modulator, on the image forming area of the electro-optic modulator in the one direction;
• and
• a projection optical system that projects the light modulated by the electro-optic modulator.