Patent ID: 6963455
Filing Date: 2005-11-08
Classification: G02B

Abstract:
1. A lens barrel comprising: a holder which holds an image pick-up device; a stationary barrel which includes a female helicoid formed on an inner peripheral surface thereof; a gear/helicoid ring which includes an annular rib formed on outer peripheral surface of said gear/helicoid ring at a rear end thereof, a male helicoid formed on said annular rib and engaged with said female helicoid of said stationary barrel, and a spur gear, wherein teeth of said spur gear are formed on each thread of said male helicoid; and a driving pinion which is engaged with said spur gear; wherein a rotation of said gear/helicoid ring via rotation of said driving pinion causes a lens group to move along an optical axis, wherein at least a portion of a rear end of said male helicoid, on threads of which said teeth of said spur gear are formed, extends rearwards to serve as a rear extension portion, and wherein at least a portion of said rear extension portion overlaps said holder in an optical axis direction when said gear/helicoid ring firstly retracts while rotating, and subsequently stops retracting at a predetermined position.