Patent ID: 7798655

Claim:
A projection unit for enlarging and projecting an image light modulated by an image formation device comprising: a plurality of curved mirrors for reflecting the image light; a plurality of mirror holding mechanisms for holding the individual curved mirror respectively; a projection base on which the mirror hold mechanisms are installed; a reference plane for the mirror holding mechanism of one of the curved mirrors to be correction target, the reference plane being positioned with respect to the projection base and extending in a direction crossing a center axis of the curved mirror; a thermal deformation member of which shape changes by a temperature rise, so that the curved mirror or a mirror holding member for holding the curved mirror is displaced to be distant from the reference plane by the change of the shape; and an urging member for urging the curved mirror to a back face side of the curved mirror toward the reference plane, wherein the mirror holding member comprises a guide tube portion for slidably holding the curved mirror on an inner face thereof, and the reference plane facing the back face of the curved mirror held by the guide tube portion, wherein the thermal deformation member is disposed between the back face of the curved mirror and the reference plane, and wherein the urging member urges the curved mirror and the thermal deformation member to the reference plane.