Patent ID: 7635229

Claim:
An optical diaphragm apparatus comprising: a diaphragm ring which includes an optical aperture; a diaphragm member which includes a rotating shaft, a driving shaft, and a shielding section; an actuator having a flexible circular arc shape which is coupled with the driving shaft, and which rotates the diaphragm member around the rotating shaft as a center; and a controlling member which controls the actuator having the circular arc shape, wherein the controlling member changes a chord length of the actuator due to bending of the circular arc shaped actuator, and the shielding section is displaced due to a change in a relative rotational operation of the driving shaft with which the actuator is coupled, with respect to the rotating shaft, which is caused due to a change in the chord length of the actuator, and an aperture diameter of the optical aperture is changed by shielding a part of the optical aperture by the shielding section, due to rotation of the diaphragm member around the rotating axis as the center.