| 摘要 |
A lens barrel is provided with a fixed cylinder, a movable cylinder supported in the fixed cylinder, and a helicoid mechanism for moving the movable cylinder along the optical axis direction through engagement of an internal helicoid of the fixed cylinder and an external helicoid of the movable cylinder. The helicoid mechanism is provided with an unengaged region, in which the internal helicoid and the external helicoid are in an unengaged state, within a rotation region between a collapsed state of the movable cylinder and a wide end of the movable cylinder. An opening or closing operation of a lens barrier is performed by the rotation of the movable cylinder in the unengaged region of the helicoid mechanism.
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