| 摘要 |
PROBLEM TO BE SOLVED: To provide a light amount adjustment device that improves diaphragm accuracy.SOLUTION: The light amount adjustment device comprises: a base plate that has an optical path opening formed at a center; a first slide ring 15 that is composed of a flexible film; a plurality of diaphragm blades that is supported to the base plate via the slide ring 15, and adjusts a light amount passing through the optical path opening; a drive ring for causing the diaphragm blade to be opened and closed; and a drive unit that drives the drive ring. The slide ring 15 is provided with a guide groove 16 for engaging with a guide pin 22 respectively formed on each of the diaphragm blades and guiding each diaphragm blade in opening and closing directions, and a groove width on a small diaphragm side of the guide groove 16 is formed to be smaller than that from an intermediate diaphragm side to an open diaphragm side. In the vicinity of the groove on the small diaphragm side of the guide groove 16, a groove 16B communicating with the groove on the small diaphragm side thereof and a cutout 15A therein are formed that relax a stress generated by the guide pin 22. |
