Patent ID: 11181714

Abstract:
A focus mechanism includes an inner barrel and an outer barrel that holds the inner barrel to allow the inner barrel to move along an optical axis. An inner peripheral surface of the outer barrel includes a medium-diameter portion having an inner diameter and a small-diameter portion having an inner diameter. The small-diameter portion is continuous to the medium-diameter portion, is positioned on a back side of the medium-diameter portion in an insertion direction ID where the inner barrel is inserted into the outer barrel. The small-diameter portion has an inner diameter that allows an X-ring absorbing the rattling of the inner barrel to be in pressure contact with the small-diameter portion in a case where the inner barrel is inserted into the outer barrel in a state where the X-ring is fitted to a groove. A boundary portion between the medium-diameter portion and the small-diameter portion is disposed at a position closer to a back side than an opening edge, which is close to the back side, of a pin-movement opening.