Patent ID: 8279398

Claim:
A deforming mechanism for deforming a transmissive optical element, the mechanism comprising: a rotation member configured to hold the optical element and to rotate around an axis parallel to a tangential line of a circumference of the optical element at a portion where the rotation member holds the optical element, so as to deform the optical element by the rotation; a torque generating unit configured to generate a torque to rotate the rotation member around the axis; a holding base; and an elastic member connecting the holding base to the torque generating unit, wherein the torque generating unit includes: (a) a component configured to apply, to a first portion of the rotation member, a first force in a direction parallel to an optical axis of the optical element; (b) a base member configured to hold the component; and (c) a contact portion that is provided to the base member and that contacts with a second portion of the rotation member, the second portion being located apart from the first portion in a direction parallel to a radial direction of the optical element, wherein the second portion of the rotation member applies a second force to the contact portion as a result of the rotation member receiving the first force from the component, and the second portion of the rotation member receives a reaction force as a result of the rotation member applying the second force to the contact portion, and wherein the torque is generated only by the first force applied to the first portion of the rotation member and the reaction force applied to the second portion of the rotation member.