Patent ID: 7303285

Claim:
A projector for projecting a projection light on a screen surface, comprising: a projection unit which converts a projection image into a projection light and projects the projection light on the screen surface; and a correction unit which corrects a distortion of the projection image by using inclination angles of a light axis of the projection light with respect to the screen surface, and which supplies the corrected projection image to the projection unit, wherein: the correction unit comprises a memory for pre-storing relational information representing relationships among the inclination angles, the projection image before correction, and the corrected projection image; and the correction unit transforms the projection image before correction, which is a quadrangle, into the corrected projection image, which is also a quadrangle, by correcting the projection image before correction by using the relational information stored in the memory and the inclination angles in such a manner that: (i) the corrected projection image is positioned within the projection image before correction, (ii) the positioned corrected projection image establishes symmetry with respect to a vertical line which passes through an intersection of the light axis of the projection light and the screen surface and is perpendicular to a ground planar surface, and (iii) at least a part of a bottom side of the corrected projection image contacts or is positioned near at least a part of a bottom side of the projection image before correction.