US Patent 7993017 Projection display apparatus

A projection display apparatus 101 in which the light quantity adjusting means has a simple and readily interchangeable structure, and which can improve image quality by adjusting the quantity of light received by a light valve continuously, without causing illuminance irregularities, and without having unwanted light radiated onto the screen, the light quantity adjusting means 9 having light blocking members 91L, 91R for blocking light in transit to a second lens array 22, and rotational axes 91LA, 91RA for turnably supporting each of the light blocking members on an xy plane, the light blocking members 91L, 91R and rotational axes 91LA, 91RA being positioned so that the rotational axes 91LA, 91RA are disposed in positions symmetric with respect to the optical axis AX on the xy plane, and the turning range from the light blocking initiation position at which the light blocking members 91L, 91R, by being turned, start to block light in transit toward the second lens array 22 to the maximum light blocking position at which the light blocking members 91L, 91R block a maximum quantity of the light in transit toward the second lens array 22 is equal to or less than ninety degrees.