| 摘要 |
PROBLEM TO BE SOLVED: To provide a lens barrel with a simple structure surely restricting a rotational angle of a rotary ring which rotates to advance/retreat and rotates at a fixed position. SOLUTION: The lens barrel has the rotary ring rotatable on a turning center axis parallel with an optical axis and moving at least one optical element in an optical axis direction by rotation; a non-rotating outer annular member supporting the rotary ring inside and having a circumferential direction groove on an inner circumferential surface opposed to the rotary ring; a rotation advancing/retreating mechanism provided between the inner circumferential surface of the outer annular member and the outer circumferential surface of the rotary ring and making the rotary ring advance/retreat between front and rear moving ends in the optical axis direction with respect to the outer annular member when rotating the rotary ring; a rotation guiding projection provided on the outer circumferential surface of the rotary ring, engaged in the circumferential direction groove when the rotary ring is moved to one moving end in the optical axis direction by the rotation advancing/retreating mechanism and rotating the rotary ring at the fixed position without moving it in the optical axis direction; and a stopper member inserted in/pulled out from a middle position in the length direction of the circumferential direction groove, engaged with the rotation guiding projection in its inserted state in the periphery direction groove so as to restrict the rotational angle of the rotary ring in the periphery direction groove and release the restriction in a detached state. COPYRIGHT: (C)2004,JPO&NCIPI
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