Patent ID: 7344255

Claim:
A light amount adjusting apparatus comprising: a light path for projecting light from a light source, at least a pair of light amount adjusting plates disposed on a peripheral side rim portion of the light path, a pair of rotation supporting shafts attached to the pair of light amount adjusting plates, respectively, said rotational supporting shafts being allocated on opposing side rim portions of said light path, so as to be able to swing in a traveling direction of the light path, a drive unit which drives to open and close said light amount adjusting plates between a narrow-down position such that they enter into the light path and a retreat position such that they retreat to outside of the light path, a restriction member which restricts rotation of said light amount adjusting plates at said retreat position, and a holding unit which holds said light amount adjusting plates to the restriction member, wherein said restriction member is a stopper member which blocks a predetermined angle or further rotation of said light amount adjusting plates, and the holding unit is a biasing member including a spring and a magnet which biases the light amount adjusting plate to this stopper member.