Patent ID: 7494225

Claim:
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 collimates 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 forming the illumination beam emitted from the illuminating device into an illumination beam having a sectional shape as to illuminate a part of an image forming area in a first direction in the image forming area of the electro-optic modulator, and to illuminate the whole of the image forming area in a second 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 of the predetermined opening part at a central portion being narrower than the width at both ends 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 first direction; and a projection optical system that projects the light modulated by the electro-optic modulator.