Patent ID: 7436447
Filing Date: 2008-10-14
Classification: G02B

Abstract:
1. A lens barrel for use with a variable magnification optical system and which is movable between a collapsed state and a photographing state, comprising: a first frame; a second frame that is arranged inside the first frame and is rotatable relative to the first frame, the second frame being movable between a first axial position in which the lens barrel is in the collapsed state and a second axial position in which the lens barrel is in the photographing state; a protrusion formed on an outer surface of the second frame; a groove formed on an inner surface of the first frame, with which the protrusion is engaged, when the second frame rotates relatively to the first frame while the groove and the protrusion engage with each other, the second frame moves relative to the first frame in a direction of an axis of the rotation; and a circumferential groove formed on the inner surface of the first frame in the circumferential direction thereof, which is connected to the groove, the first frame and the second frame are relatively rotatable without changing the relative position in the direction of the axis of rotation when the protrusion is in the circumferential groove; wherein a magnification change is performed by rotating the second frame in the second axial position in such a manner that the protrusion moves along the circumferential groove.