Zoom lens mount assembly

• US 5,037,187 A
• Filed: 07/14/1989
• Issued: 08/06/1991
• Est. Priority Date: 08/12/1988
• Status: Expired due to Term

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Sakai, Nobuhiro, Nakao, Kanji, Oda, Akira, Kameoka, Seiji, Yanagidaira, Hidetoshi, Atsuta, Toshikatsu
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): Ben, Loha
• Application Number:
  US07/380,140
• Time in Patent Office: 753 Days
• Field of Search: 350/429, 350/430, 350/255, 354/400, 354/195.11, 354/195.12
• US Class Current: 359/699
• CPC Class Codes: G02B 7/10 by relative axial movement of several lenses, e.g. of varifocal objective lens

Abstract

A zoom lens mount assembly in which a zooming cam frame is moved along the optical axis while rotating therearound and respective movable frames supporting an optical system are driven by such rotation and movement of the cam frame to effect a desired zooming. In another aspect there is provided a focussing cam frame adapted to be moved along the optical axis and to drive a movable frame provided with a focussing optical system and a program lens shutter.

Claims

1. Zoom lens mount assembly comprising:

an optical system having an optical axis;

a plurality of movable frames including a main movable frame adapted to support the optical system, at least one of the movable frames having a plurality of cam followers;

a zooming cam frame for moving the plurality of movable frames in operative association with rotation of said zooming cam frame to achieve an optical variable magnification, said zooming cam frame being coupled to said main movable frame of the plurality of movable frames so that, around the optical axis, only said zooming cam frame is rotatable but, along the optical axis, said zooming cam frame is movable together with said main movable frame;

a stationary frame having stationary cam followers; and

at least first and second sets of cam tracks provided on said zooming cam frame, the first set of cam tracks being operatively associated with said stationary cam followers and the second set of cam tracks being operatively associated with the cam followers of the one movable frame wherein the respective movable frames are moved along the optical axis by rotation of said zooming cam frame and the movement of said zooming cam frame along the optical axis occurs concurrently with said rotation thereof.

2. Zoom lens mount assembly as recited in claim 1, wherein the zooming cam frame is circumferentially provided therearound with arc-shaped slots while said main movable frame is circumferentially provided therearound with a first set of arc-shaped ridges so that said first set of arc-shaped ridges are slidably received by said arc-shaped slots to form a bayonet structure and thereby said zooming cam frame is rotatable with respect to said main movable frame but operatively associated with said main movable frame so as to be movable together with said main movable frame in the direction of the optical axis.

3. Zoom lens mount assembly as recited in claim 1 for use with a motor driven pinion, wherein said zooming cam frame is provided therearound with a drive gear comprising a gear portion angled with respect to the direction of rotation of said zooming cam frame so that said cam frame is driven by a motor driven pinion adapted to be engaged with said drive gear.

4. Zoom lens mount assembly as recited in claim 1 further comprising a focussing optical system and a focussing cam frame wherein said zooming cam frame is coupled to said main movable frame on its front side while said focussing cam frame is coupled to said main movable frame on its rear side so that said focussing cam frame is rotatable around the optical axis independently from the zooming cam frame but is movable along the optical axis together with said zooming cam frame;

said assembly further comprising a focussing movable frame of the plurality of movable frames adapted to support the focussing optical system and operatively associated with said focussing cam frame.

5. Zoom lens mount assembly as recited in claim 4, wherein said focussing cam frame is circumferentially provided with arc-shaped slots while said main movable frame is circumferentially provided with a second set of arc-shaped ridges so that said second set of arc-shaped ridges are slidably received by said arc-shaped slots to form a bayonet structure and thereby said focussing cam frame is rotatable with respect to said main movable frame but operatively associated with said main movable frame so as to be moved together with said main movable frame in the direction of the optical axis.

6. Zoom lens mount assembly as recited in claim 4, wherein said focussing movable frame is provided with lens shutter assembly attached thereto in addition to the focussing optical system so that said shutter assembly is displaced along the optical axis during rotation of said zooming cam frame and said focussing cam frame.

7. Zoom lens mount assembly comprising:

an optical system having an optical axis;

a generally cylindrical stationary frame including stationary cam followers;

a plurality of movable frames adapted to support the optical system, the plurality of movable frames including a generally cylindrical main movable frame having a plurality of cam slots, said main movable frame being slidably received about an exterior surface of said stationary frame, and said stationary cam followers slidably engaging the corresponding number of the plurality of cam slots; and

a generally cylindrical zooming cam frame slidably received about an exterior surface of said main movable frame for moving the plurality of movable frames in operative association with rotation of said zooming cam frame to achieve an optical variable magnification, said zooming cam frame being in camming engagement with said stationary cam followers of said stationary frame and being coupled to said main movable frame so that rotation of said zooming cam frame around an optical axis causes said main movable frame together with said cam frame to move along the optical axis with respect to said stationary frame.

8. Zoom lens mount assembly as recited in claim 7 wherein said zooming cam frame has at least first and second sets of cam tracks, the first set of cam tracks being operatively associated with said stationary cam followers and the second set of cam tracks being operatively associated with cam followers of another movable frame of the plurality of movable frames, wherein the respective movable frames are moved along the optical axis by rotation of said zooming cam frame and the movement of said zooming cam frame along the optical axis occurs concurrently with said rotation thereof.

9. Zoom lens mount assembly as recited in claim 8, wherein said zooming cam frame has arc-shaped slots provided circumferentially therearound, and said main movable frame has a first set of arc-shaped ridges provided circumferentially therearound so that said first set of arc-shaped ridges are slidably received by said arc-shaped slots to form a bayonet structure wherein said zooming cam frame is rotatable with respect to said main movable frame but operatively associated with said main movable frame so as to be movable together with said main movable frame in the direction of the optical axis.

10. Zoom lens mount assembly as recited in claim 8, wherein said zooming cam frame has a drive gear provided on the exterior surface thereof, said drive gear comprising a gear portion angled with respect to the direction of rotation of said zooming cam frame so that said cam frame is driven by a motor driven pinion adapted to be engaged with said drive gear.

11. Zoom lens mount assembly as recited in claim 8, further comprising a focussing cam frame slidably received about the exterior surface of said main movable frame, said focussing cam frame being rotatable around the optical axis independent of said zooming cam frame but movable along the optical axis together with said zooming cam frame, wherein said zooming cam frame is coupled to said main movable frame on its front side while said focussing cam frame is coupled to said main movable frame on its rear side;

said assembly further comprising a focussing movable frame of the plurality of movable frames adapted to support the focussing optical system and operatively associated with said focussing cam frame.

12. Zoom lens mount assembly as recited in claim 11, wherein said focussing cam frame has arc-shaped slots provided circumferentially therearound, and said main movable frame has a second set of arc-shaped ridges circumferentially provided therearound so that said second set of arc-shaped ridges are slidably received by said arc-shaped slots to form a bayonet structure whereby said focussing cam frame is rotatable with respect to said main movable frame but operatively associated with said main movable frame so as to be moved together with said main movable frame in the direction of the optical axis.

13. Zoom lens mount assembly as recited in claim 11, wherein said focussing movable frame carries lens shutter means fixed thereto so that said shutter means is displaced along the optical axis together with said focussing optical system during rotation of said zooming cam frame and said focussing cam frame.

14. A zoom lens mount assembly, comprising:

an optical system comprising a plurality of lenses aligned to define an optical axis;

a generally stationary frame having a cam follower;

a main movable frame slidingly carried by the stationary frame and adapted to carry one or more lenses of the optical system; and

a generally cylindrical zooming cam frame slidingly and rotationally carried by the stationary frame and rotationally coupled to the main movable frame, said zooming cam frame having a camming surface positioned to engage the stationary cam follower of the stationary frame upon rotation of the zooming cam frame and shaped so as to axially displace, upon rotation of the zooming cam frame, the zooming cam frame and the main movable frame which is rotationally coupled to the zooming cam frame.

15. The assembly of claim 14 further comprising an additional movable frame slidingly carried by the stationary frame and adapted to carry at least one lens of the optical system, said additional movable frame having a second cam follower and said zooming cam frame having a second camming surface positioned to engage the cam follower of the additional movable frame upon rotation of the zooming cam frame and shaped so as to axially displace, upon rotation and axial displacement of the zooming cam frame, the additional movable frame.

16. The assembly of claim 15 further comprising a generally cylindrical focusing cam frame rotationally carried by the main movable frame, said assembly further comprising a second additional movable frame slidingly carried by the stationary frame and adapted to carry at least one lens for focusing the optical system, said second additional movable frame having a third cam follower and said focusing cam frame having a third camming surface positioned to engage the cam follower of the second additional movable frame upon rotation of the focusing cam frame and shaped so as to axially displace, upon rotation of the zooming cam frame, the second additional movable frame.