Patent ID: 6599035
Filing Date: 2003-07-29
Classification: G02B

Abstract:
A lens drive system comprising:a lens case which supports an image pick-up device; a movable lens frame which supports a lens group via which an image is focused on said image pick-up device, said movable lens frame being guided linearly in an optical axis direction thereof, the front of said movable lens frame being projectable forward from said lens case; a reversible motor which is supported by said lens case; a feed screw supported by said lens case to be driven by said reversible motor; a half nut which moves together with said movable lens frame in the optical axis direction, wherein said half nut is normally engaged with said feed screw, and is disengaged from said feed screw to slide on said feed screw when more than a predetermined force is applied to said half nut in the optical axis direction; and a plurality of ribs formed integral with said lens case which project from an inner surface of said lens case behind a space for movement of said movable lens frame; wherein each of said plurality of ribs includes a stop surface formed at an end of said each rib which faces said movable lens frame, said stop surfaces coming into contact with a rear surface of said movable lens frame when said movable lens frame retreats while said half nut is sliding on said feed screw.