Claims
- 1. 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.
- 2. The zoom lens mechanism according to claim 1, wherein said shift cam mechanism comprises:
a shift cam surface provided on the rear end of said first sub-lens group frame; and a follower projection, provided on said second sub-lens group frame, which projects in a forward direction and engages with said shift cam surface.
- 3. The zoom lens mechanism according to claim 1, wherein said switching lens group frame includes a shutter retaining ring for retaining a shutter and a front annular member attached at the front of said shutter retaining ring;
wherein said first sub-lens group frame, said second sub-lens group frame, and said actuator ring are held between said shutter retaining ring and said front annular member; and wherein said biasing device is arranged between said front annular member and said first sub-lens group frame.
- 4. The zoom lens mechanism according to claim 3, wherein a linear guide rod is provided in said front annular member in order to linearly guide said first sub-lens group frame in the optical axis direction;
and wherein said biasing device comprises a coil spring provided around said linear guide rod.
- 5. The zoom lens mechanism according to claim 3, wherein said receiving surface is provided on said shutter retaining ring.
- 6. The zoom lens mechanism according to claim 1, wherein a focus cam mechanism is provided on opposed surfaces of said actuator ring and said second sub-lens group frame, said focus cam mechanism moving said first sub-lens group frame integrally with said second sub-lens group frame in the optical axis direction, in accordance with the rotation of said actuator ring, while maintaining said first and second sub-lens group frames in one of said mutually close position and said mutually distant position.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-288547 |
Sep 2000 |
JP |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application relates to the following U.S. patent applications, all filed concurrently herewith on Sep. 24, 2001, and all of which are expressly incorporated herein by reference in their entireties: “ZOOM LENS MECHANISM” having attorney docket No. P21180, “ECCENTRICITY-PREVENTION MECHANISM FOR A PAIR OF LENS-SUPPORTING RINGS” having attorney docket No. P21182, “REDUCTION GEAR MECHANISM” attorney docket No. P21183, “RING MEMBER SHIFT MECHANISM AND LENS GROUP SHIFT MECHANISM“having attorney docket No. P21184, “LENS BARREL” having attorney docket No. P21185, “LENS BARREL” having attorney docket No. P21186, “LENS BARREL” having attorney docket No. P21187, “LENS BARREL” having attorney docket No. P21188, “ZOOM LENS BARREL” having attorney docket No. P21190, and “LENS BARREL” having attorney docket No. P21192, each naming as inventors Hiroshi NOMURA et al.; and “LENS DRIVE CONTROL APPARATUS FOR ZOOM LENS SYSTEM HAVING A SWITCHING LENS GROUP” having attorney docket No. P21189 and naming as inventor Norio NUMAKO.