Patent ID: 7204596

Claim:
A projector having a tilt angle measurement device for projecting an image onto a projection surface, said projector comprising: a projection device for projecting an image onto said projection surface; a tilt angle measurement device for calculating the tilt angle that is formed between an axis of projection of said projection device and said projection surface; and an image control unit for controlling an output image of said projection device in accordance with the calculated tilt angle to correct distortion in the image that is projected onto said projection surface; wherein said tilt angle measurement device comprises: a light guide unit that is provided on a projection-side surface of a case of said projector and that is separated in a prescribed direction from said axis of projection; a photodetection element for receiving, by way of said light guide unit, reflected light from at least two points that are projected onto said projection surface; and a tilt angle calculation unit for calculating the tilt angle that is formed between said axis of projection of said projection device and said projection surface based on photodetection position information of said reflected light of said photodetection element.