Patent ID: 6707620
Filing Date: 2004-03-16
Classification: G02B

Abstract:
A zoom lens mechanism for moving a switching lens group of a zoom lens system, said switching lens group constituting one of a plurality of variable lens groups of the zoom lens system which move in an optical axis direction upon zooming, and including first and second sub-lens groups, which are arranged in that order from the object side, wherein said first and said second sub-lens groups serve as a focusing lens group in a mutually close position and in a mutually distant position in the optical axis direction, said zoom lens mechanism comprising:a switching lens group frame supporting a first sub-lens group frame and a second sub-lens group frame in a manner that allows relative rotation and linear displacement of the first and second sub-lens group frames in the optical axis direction, said first and second sub-lens group frames supporting said first and second sub-lens groups, respectively; a shift cam mechanism provided on opposed surfaces of said first sub-lens group frame and said second sub-lens group frame, respectively, said shift cam mechanism causing said first and second sub-lens group frames to move to one of said mutually close position and said mutually distant position, in accordance with relative rotation between said first sub-lens group frame and said second sub-lens group frame; an actuator ring for providing the relative rotation between said first sub-lens group frame and said second sub-lens group frame, said actuator ring being rotatably retained in said switching lens group frame and engaged with said second sub-lens group frame to cause said relative rotation between said first sub-lens group frame and said second sub-lens group frame; a receiving surface provided on said switching lens group frame wherein a rear end surface of said actuator ring abuts against said receiving surface; and a biasing device for biasing said first sub-lens group frame toward said actuator ring to force said first sub-lens group frame, said second sub-lens group frame, and said actuator ring against said receiving surface, so that said shift cam mechanism provided on said first and second sub-lens group frames come into contact with each other.