Patent ID: 7099576
Filing Date: 2006-08-29
Classification: G02B

Abstract:
1. A lens barrel comprising: a distance adjustment ring which is rotatable by a motor and which moves a movable lens group along said optical axis when said distance adjustment ring is rotated on about an axis thereof; a hand-operated ring which rotates said distance adjustment ring when said hand-operated ring is manually rotated; and a first one-way rotational transfer mechanism which transfers torque of said hand-operated ring to said distance adjustment ring when said hand-operated ring is manually rotated, and for preventing torque of said distance adjustment ring from being transferred to said hand-operated ring when said distance adjustment ring is rotated by said motor; wherein said first one-way rotational transfer mechanism comprises: an annular overlapping portion formed on said hand-operated ring and overlaps said distance adjustment ring in a radial direction of said lens barrel; a first orthogonal surface formed on said hand-operated ring to lie in a plane orthogonal to an axis of said hand-operated ring; a first torque transfer cylindrical surface formed on one of an inner peripheral surface and an outer peripheral surface of said distance adjustment ring to face said annular overlapping portion; at least one first circumferentially-uneven-width-space forming portion formed on said annular overlapping portion to form at least one first accommodation space between said annular overlapping portion and said first torque transfer cylindrical surface, said first accommodation space having different radial widths at different circumferential positions; a first differential rotating member installed in said first accommodation space, and pressed against said first orthogonal surface by a first biasing device, said first differential rotating member revolving about said axis of said hand-operated ring in a same direction as a rotational direction of said hand-operated ring while revolving at a slower speed than said rotation of said hand-operated ring in association with said rotation of said hand-operated ring; and at least one first torque transfer member installed in said first accommodation space, said first torque member revolving around said axis of said hand-operated ring in a same revolving direction as said first differential rotating member when pressed by said first differential rotating member, wherein said first circumferentially-uneven-width-space forming portion is shaped so that said first torque transfer member which revolves in a circumferential direction about said axis of said hand-operated ring wedges between said circumferentially-uneven-width-space forming portion and said first torque transfer cylindrical surface to transfer said torque of said hand-operated ring to said distance adjustment ring when said hand-operated ring is manually rotated.