PROJECTOR AND ITS CONTROLLING METHOD

摘要

A safe and high-brightness projector is realized. In this projector, a light flux from a light source (101) is irradiated on an image modulation device (105) and an image formed in the image modulation device (105) is expanded and projected by a zoom lens (102). The projector is equipped with a light transmission window (103) disposed in front of a light emission surface of the zoom lens (102) in such a manner as to move along the optical axis. The projector is also equipped with a window position controlling portion (108) which controls the position of the light transmission window (103) so that a light flux region appearing on the external side face of the light transmission window (103) may not change with a change in focal length of the zoom lens (102).