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