Optical: systems and elements – Lens – With variable magnification
Reexamination Certificate
1999-09-02
2001-07-31
Mack, Ricky (Department: 2873)
Optical: systems and elements
Lens
With variable magnification
C359S700000
Reexamination Certificate
active
06268968
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lens housing that contains image-capturing lenses and lens frames adapted to move forward and backward.
2. Description of the Related Art
Conventionally, a zoom-lens housing has been proposed as a lens housing that contains movable frames in Japanese Unexamined Patent Publication No. 4-52628. The proposed zoom lens housing rotates inner and outer zoom rings about an optical axis to move all lens frames forwardly and backwardly in a direction corresponding to the optical axis. According to the forward and backward movement of the lenses, the focal length of the zoom lens is varied. Further, according to the forward and backward movement of the lenses caused by the outer zoom ring, the lens housing moves a focusing-lens-group frame forward and backward to perform focusing operations.
In the above zoom lens housing the focusing lens group is moved forward and backward by the outer zoom ring. A coupling member for coupling the outer zoom ring and the focusing-lens-group frame is formed of a slender plate. The coupling member receives not only simple thrusting forces but also torsional forces in the radial direction. Responsive to these forces, the outer zoom ring (which is a frame member) and the focusing-lens-group frame are deformed. The deformations cause problems in that smooth extending and retracting operations cannot be performed, and that the aforementioned coupling member is deformed.
Also, conventionally, a collapsible lens housing that contains image-capturing lenses and has movable frames (frame members) in an image-capturing region has been proposed in Japanese Unexamined Utility Model Publication No. 11-171412. The proposed lens housing also has relief grooves formed continuously in cam grooves of a cam cylinder, which engage with cam followers provided for reduction of an inter-lens-group distance when shifting the lens housing into a collapsed-barrel state. With this lens housing, the cam followers can be engaged with the relief grooves and increase lens extension.
However, in the lens housing proposed in the Japanese Unexamined Utility Model Publication No. 11-171412, in addition to the cam grooves for moving the movable frames through the cam cylinder, relief grooves must be provided. This requires extra space, restricting the shape of the movable frames and decreasing rigidity.
SUMMARY OF THE INVENTION
In order to solve the problems described above, an object of the present invention is to provide a lens housing containing movable frame members which produces smooth and precise movement, has sufficiently rigid movable frames and allows miniaturization.
According to one aspect of the present invention, a lens housing includes frame members that are movable in a direction corresponding to an optical axis; a separate cam-follower member slidably supported in the direction corresponding to the optical axis positioned where the cam-follower member opposes and is spaced from the frame members and where the cam-follower member is engaged with the frame members; and a driving member for driving the cam-follower member. In this lens housing, the frame members are driven forward and backward via the cam-follower member.
According to another aspect of the present invention, a rotating-frame member is rotatably and movably connected to an immobilized frame and rotationally driven; a first frame member linearly movably in the rotating frame in a direction corresponding to an optical-axis relative to the immobilized frame; and a cam-follower member, movably supported in a direction corresponding to the optical axis relative to the rotating frame and the first frame member, adapted to position in a direction corresponding to an optical axis the first frame member by engaging with the first frame member and having a cam follower for engaging with cams of the rotating frame, whereby a rotational driving force of the rotating frame is converted and transmitted for moving the first frame member linearly. In this lens housing, the first frame member is driven forward and backward in a direction corresponding to the optical axis according to rotation of the rotating frame member via the cam-follower member.
Other characteristics and advantages of the present invention will be clarified sufficiently according to the description below.
REFERENCES:
patent: 3906529 (1975-09-01), Filipovich
patent: 5926324 (1999-07-01), Oono et al.
patent: 1-171412 (1989-12-01), None
patent: 4-52628 (1992-02-01), None
patent: 6-294921 (1994-06-01), None
Mack Ricky
Olympus Optical Co,. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
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