Photography – Folding or collapsible camera – Having axially moving lens
Reexamination Certificate
2003-04-16
2004-12-28
Gray, David M. (Department: 2851)
Photography
Folding or collapsible camera
Having axially moving lens
C396S451000, C396S462000
Reexamination Certificate
active
06835006
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lens barrel which is variable in a barrel length between a storage state relatively short in a barrel length and an image taking state relatively long in a barrel length, and a camera having such a lens barrel.
2. Description of the Related Art
Hitherto, such a type of camera that photography is performed on a silver halide film comes into wide use. And recently, in addition to such a type of camera, there rapidly comes into wide use an electronic camera in which a subject is image-formed on a solid state imaging device such as a CCD imaging device to derive image data representative of the subject. The camera of such a type that photography is performed on a silver halide film and the electronic camera as mentioned above are simply referred to as a “camera”.
Generally, a camera requires a high order of portability. And thus there is widely used a collapse and extension type of lens barrel arranged in such a manner that a lens barrel holding an image taking lens is collapsed into a camera body side when the camera is not used, and the lens barrel projects from the camera body side ahead when photograph is performed. Also in the conventional so called-compact camera and the recent electronic camera, there are widely used a lens shutter and an aperture disposed between image taking lenses.
In the lens barrel variable in collapse and extension and a camera provided with the lens shutter and the aperture, as mentioned above, it is a problem as to how the portability is improved.
In this case, as one of points contributing to an improvement of the portability, there may be raised thinness of a lens barrel at the time of collapse in an optical axis direction.
FIG. 17
is a sectional view of a lens barrel of the conventional camera at the time of collapse taken along optical axis S.
FIG. 17
shows a collapse and extension type of lens barrel
10
. The lens barrel
10
comprises an image taking lens
20
consisting of a first group lens
21
, a second group lens
22
and a third group lens
23
, and a lens shutter
30
disposed between the first group lens
21
and the second group lens
22
of the image taking lens
20
. The lens barrel
10
is of a zoom lens structure capable of adjusting a focal length at the time of extension as well as permission of collapse and extension. At the rear portion of the lens barrel
10
, there is disposed a CCD imaging device
40
which is fixed on a camera body side. That is, here, there is shown a lens barrel
10
for an electronic camera.
As shown in
FIG. 17
, of the lens groups constituting the image taking lens
20
, the second group lens
22
and the third group lens
23
are disposed at mutually very closed positions in the collapsed state shown in FIG.
17
. However, between the first group lens
21
and the second group lens
22
, there is the lens shutter
30
, and thus the first group lens
21
and the second group lens
22
are disposed away from one another to some extent putting the lens shutter
30
therebetween. This makes it impossible to reduce the size of the lens barrel at the time of the collapse.
For example, Japanese Patent Laid Open Gazette Hei. 6-258702 discloses a camera in which a photographic optical system of a single focal point comprising a plurality of lens groups is movable between an initial position for a photography and a collapsed position saved from the initial position to a camera main body side, wherein the camera has a mechanism that when the photographic optical system is moved to the collapsed position, the plurality of lens groups is reduced in interval among the lens groups as compared with that of the initial position so that the length of occupation of the photographic optical system is altered.
Further Japanese Patent Laid Open Gazette Hei. 10-288731 discloses a zoom lens, which is miniaturized by improvement of an aperture driving mechanism. However, this is not to solve the problems of the aperture and the shutter per se. And thus, there is a limit of miniaturization.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide a lens barrel capable of reducing a size (a barrel length) in an optical axis direction as compared with the conventional lens barrel which is variable in a barrel length between a collapsing state and an extension state, and also provide a camera provided with such a lens barrel.
To achieve the above-mentioned objects, the present invention provides a lens barrel which is variable in a barrel length between a storage state relatively short in a barrel length and an image taking state relatively long in a barrel length, wherein the lens barrel incorporates therein a image taking lens consisting of a plurality of lens groups, the lens barrel comprising:
a light quantity control member which is in a use state that a light quantity of a photographic light passing through the image taking lens is controlled, when the lens barrel is in the image taking state, and which is in a non-use state that an opening is kept on a predetermined aperture size; and
a lens movement mechanism that moves at least part of members constituting any lens group of the plurality of lens groups constituting the image taking lens to a state that the part comes into the opening of the light quantity control member, when the lens barrel moves from the image taking state to the storage state.
In the lens barrel according to the present invention as mentioned above, it is acceptable that the light quantity control member is a lens shutter or an aperture member. Alternatively, it is acceptable that the light quantity control member is a member used both as a lens shutter and an aperture member.
According to the lens barrel of the present invention, at least part of members constituting any lens group of the plurality of lens groups constituting the image taking lens is moved to a state that the part comes into the opening of the light quantity control member, when the lens barrel moves from the image taking state to the storage state. This feature makes it possible to reduce the barrel length in the storage state as compared with the conventional one.
In the lens barrel according to the present invention as mentioned above, it is preferable that when the light quantity control member is in the non-use state, the light quantity control member maintains the opening in an opening state that the opening is opened more than a maximum aperture in the use state.
There is a need to determine the maximum aperture in the image taking state from the viewpoint of the image taking efficiency. The size of the maximum aperture in the image taking state is not always an aperture size sufficient for accommodating at least part of members constituting any lens group of the plurality of lens groups in the opening of the light quantity control member, at the time of the storage state. In this case, when the lens barrel is in the storage state, the light quantity control member maintains the opening in an opening state that the opening is opened more than a maximum aperture in the image taking state. Thus, it is possible to satisfy both the image taking ability and the storage ability.
In the lens barrel according to the present invention as mentioned above, it is preferable that the lens barrel further comprises a compulsory changing over member that forcibly changes over the light quantity control member to the non-use state, before the part is in contact with the light quantity control member, when the lens barrel moves from the image taking state to the storage state.
Even if a malfunction of the lens control system or a mechanical shock in operation bring about an approach of the lens groups to the light quantity control member, the presence of the compulsory changing over member makes it possible to avoid a mechanical destroy of the lens barrel since the light quantity control member moves to the non-use state.
In the lens barrel according to the present invention as mentioned above, it is prefer
Ishizuka Kazunori
Kondo Shigeru
Orimoto Masaaki
Tanaka Yasuhiko
Arnold Bruce Y.
Arnold International
Fuji Photo Optical Co., Ltd.
Gray David M.
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