Projection lens shifting mechanism

A projection lens shifting mechanism provided in a projector apparatus for projecting a light beam from a light source onto a screen by way of a projection lens to make an enlarged projection of an image rendered on a display device;

• said projection lens shifting mechanism comprising:
• a base plate secured to the housing of said projection lens shifting mechanism, provided with a guide surface that is parallel to the display surface of said display device;
• a moveable plate capable of rigidly holding said projection lens, and, when in a moveable state, moving in a prescribed direction parallel to the display surface of said display device while being guided by said guide surface of said base plate;
• a holding plate linked to said moveable plate by way of elastic members;
• constituting, together with said moveable plate, an elastic clamping structure that holds said base plate from both sides with said base plate interposed between said holding plate and said moveable plate and that clamps said base plate by means of the elastic force of said elastic members;
• and, when an external force works against said elastic force to release the clamping, being rendered moveable to move integrally with said moveable plate in a direction parallel to said guide surface of said base plate;
• an engagement structure that is interposed between said holding plate and said base plate, said engagement structure, when said clamping structure is clamping said base plate, engaging said holding plate with said base plate to place said holding plate in a locked state, i.e., a state in which said holding plate cannot move with respect to said base plate in a direction parallel to the guide surface of said base plate;
• and
• an engagement-release structure for releasing the engagement brought about by said engagement structure and switching said holding plate from said locked state to a moveable state.