Patent ID: 7789518

Claim:
An imaging system, projecting an image beam provided by a light valve unto a screen, the imaging system comprising: a projection lens, disposed on an optical path of the image beam to project the image beam unto the screen; and a light beam modulation module, disposed between the projection lens and the light valve, the light beam modulation module comprising: a fixed light shutter, disposed on the optical path of the image beam and shielding off a portion of the circumferential light of the image beam, wherein the fixed light shutter comprises a first opening; and a movable light shutter, moving into the optical path of the image beam so as to shield off another portion of the circumferential light of the image beam, wherein the movable light shutter comprises a second opening facing the first opening, the fixed light shutter is a half-annular shape and the movable light shutter is a plate, and both of the first opening and the second opening are half-circular openings.