Photography – Having variable focal length of camera objective – Having direct viewfinder
Reexamination Certificate
1999-09-24
2001-10-16
Perkey, W. B. (Department: 2851)
Photography
Having variable focal length of camera objective
Having direct viewfinder
C396S379000
Reexamination Certificate
active
06304727
ABSTRACT:
This application is based on application No. Hei 10-271114 filed in Japan, the content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a viewfinder having a zooming function. The present invention also relates to a camera having such viewfinder.
2. Description of the Prior Art
In many conventional cameras capable of zooming, the cam for zooming held on the finder unit is driven by being interlocked with a zoom drive system in the lens barrel of the taking lens or the lens barrel itself by use of gears or the like. In recent years, a camera has been put on the market in which zooming of the viewfinder is performed by driving the zoom cam held on the lens barrel of the taking lens by interlocking it with an axially movable barrel of the lens barrel.
However, the former structure is disadvantageous in cost and size reduction of the camera because a mechanical member for the interlocking such as a gear is necessary. In addition, a deviation is caused between the zooming of the lens barrel of the taking lens and the zooming of the viewfinder because of a backlash in the mechanical member, so that the magnification of the viewfinder deviates for the actually taken image.
In the latter structure in which the zooming of the viewfinder is carried out by the zoom cam on the taking lens barrel, since the accuracy of the lens units of the viewfinder are dependent on the assembly condition other than the viewfinder, the error of the relative position becomes large, and this incurs degrading of the performance. Since the zoom cam is not integrated in the finder unit until the finder unit is combined with the taking lens barrel, it is impossible to confirm the function and performance of the finder unit alone during camera manufacturing. In addition, since the cam follower for the zoom cam to be provided on the finder unit is mounted when the entire camera is assembled, the assembly is difficult.
SUMMARY OF THE INVENTION
In view of the above-described problem, an object of the present invention is to provide a low-cost and space-saving viewfinder in which the deviation between the zooming of the lens barrel of the taking lens and the zooming of the viewfinder is small, the assembly is easy and the function and the performance can easily be guaranteed.
Another object of the present invention is to provide a camera having such viewfinder.
To achieve the above-mentioned object, according to one aspect of the present invention, in a viewfinder comprising a plurality of lens units and performing zooming by driving at least one of the plurality of lens units in a direction of an optical axis, a finder unit for holding the plurality of lens units has a cam driven by a member integrally driven with a lens barrel member so as to drive the lens unit in the direction of the optical axis.
The lens barrel member is an axially movable barrel in the lens barrel of the taking lens. The cam is a flat shaped cam plate.
The cam has on one surface a groove-form bottomed cam for driving the lens unit and has on the other surface a groove-form bottomed cam for interlocking with the lens barrel member.
An opening is provided for engaging the cam with the driven lens unit. The opening is always covered with the cam in a drive region where zooming is performed.
A stationary barrel surrounding the lens barrel member is provided in the lens barrel of the taking lens. The stationary barrel has an opening for engaging the cam with the lens barrel member. The opening is always covered with the cam in the drive region where zooming is performed.
These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings, which illustrate specific embodiments of the invention.
REFERENCES:
patent: 4944030 (1990-07-01), Haraguchi et al.
patent: 5655159 (1997-08-01), Nakayama et al.
patent: 10177198 (1998-06-01), None
McDermott & Will & Emery
Minolta Co. , Ltd.
Perkey W. B.
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