Photography – With viewfinder – Selective or adjustable viewfinder field
Reexamination Certificate
2000-09-29
2002-11-05
Gray, David M. (Department: 2851)
Photography
With viewfinder
Selective or adjustable viewfinder field
C396S436000
Reexamination Certificate
active
06477333
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image frame changing apparatus which can change a finder view frame or a photographing frame of a camera in frames with plural aspect ratios such as a high-vision size, a convention size, and a panoramic size.
2. Description of Background Art
A camera which can change a photographing size is provided with a view frame changing apparatus in an optical path of a finder optical system of the camera. The view frame changing apparatus can change a size of the view frame in a size corresponding with a size of the photographing frame.
A conventional view frame changing apparatus in
FIG. 10
is a changing apparatus which can change the view frame in a high-vision size, a conventional size, and a panoramic size, and is constructed of a rectangular high-vision view frame
1
, a pair of L-shaped convention/panoramic view frames
2
A and
2
B, and a drive ring
3
.
A pair of cam pins
4
A and
4
B are projected at the high-vision view frame
1
, and L-shaped cam grooves
5
A and
5
B which are formed at the convention/panoramic view frame
2
A and
2
B, are slidably overlapped and engaged with the pair of cam pins
4
A and
4
B. A pair of guide pins
6
A and
6
B are projected at the drive ring
3
. The guide pin
6
A is slidably engaged with a long hole
7
A of the convention/panoramic view frame
2
A, whereas the guide pin
6
B is slidably engaged with a long hole
7
B of the convention/panoramic view frame
2
B.
By the above-described structure, the convention/panoramic view frames
2
A and
2
B are pushed by the guide pins
6
A and
6
B when the drive ring
3
rotates with a rotation axis
8
as the center, whereby the convention/panoramic view frames
2
A and
2
B are moved in opposite directions to each other on a plane which is parallel with the high-vision frame
1
while being guided by the cam pins
4
A and
4
B and the cam grooves
5
A and
5
B.
Thus, when rotating the drive ring
3
in a state in
FIG. 10
(a high-vision state) in a counterclockwise direction with the rotation axis
8
as the center, the convention/panoramic view frames
2
A and
2
B are moved closer to each other in horizontal directions, so the view frame is changed to the view frame in the convention size. Moreover, when rotating the drive ring
3
in a clockwise direction from the state in
FIG. 10
with the rotation axis
8
as the center, the convention/panoramic view frames
2
A and
2
B are moved closer to each other in vertical directions, so the view frame is changed in the panoramic size.
Japanese Patent Application Laid-open No. 8-160498 discloses an image frame changing apparatus which can change an image frame of optical equipment such as a finder view frame for a camera. The image frame changing apparatus uses a mechanism in which a pair of L-shaped image frame regulating members are moved by an arched cam groove.
However, the image frame changing apparatus disclosed in Japanese Patent Application Laid-open No. 8-160498 has a large image frame regulating members and the entire apparatus itself is thus large, because the arched cam grooves are formed in areas of obtuse angles in between two diagonal lines.
Moreover, because the cam grooves
5
A and
5
B of the convention/panoramic view frames
2
A and
2
B of the conventional view frame changing apparatus in
FIG. 10
are formed in an L-shaped pattern by bending the cam grooves at 90 degrees, when sliding the cam pins
4
A and
4
B on the cam grooves
5
A and
5
B, the cam pins
4
A and
4
B are caught at a corner of the cam grooves
5
A and
5
B, and hence the convention/panoramic view frames
2
A and
2
B do not move smoothly.
The cam grooves
5
A and
5
B are the same as the arched cam groove of Japanese Patent Application No. 8-160498 in that the majority of the cam grooves are formed in areas of the two diagonal lines A and B in between the obtuse angle &bgr; of the image frame. Thus the convention/panoramic view frames
2
A and
2
B are large and the entire image view changing apparatus is large.
SUMMARY OF THE INVENTION
The present invention has been developed in view of the above-described circumstances, and has as its object the provision of the image frame changing apparatus which is compact in size by positioning the cam groove of the cam guiding device which constructs the image frame changing apparatus for the camera at a better position.
In order to achieve the above-described objects, the present invention provides the image frame changing apparatus for a camera in which a pair of L-shaped image frame changing members are arranged to face each other in a direction of a diagonal line of a rectangular image frame, and the image frame changing members are guided by a cam guiding device with a cam pin and cam grooves while moving the image frame changing members in opposite directions to each other on a plane that is parallel with said image frame, whereby changing sizes of the image frame in plural sizes, the image frame changing apparatus characterized in that: the cam grooves of the cam guiding device are in areas of acute angles in between the two diagonal lines of the image frame.
According to the present invention, the cam grooves are formed in the areas in between the two diagonal lines forming acute angles. As a result, the image frame changing members can be small in size, which thus makes the frame changing apparatus compact in size.
Since the cam grooves of the present invention are arched by a predetermined curvature, the cam pins slide smoothly in the entire area of the cam grooves without being caught in the cam grooves. The curvature for the cam grooves is preferable to be small, which means it should be almost straight.
Further, the image frame changing apparatus for the camera of the present invention can be used for a changing unit for changing a finder view frame or a photographing frame of a camera in frames with plural aspect ratios. By use of the image frame changing apparatus of the present invention, an arrangement of the image frame changing apparatus can be kept small; therefore a finder optical unit and a photographing optical unit can be compact in size.
REFERENCES:
patent: 5583593 (1996-12-01), Terada
patent: 5732298 (1998-03-01), Nishizawa et al.
patent: 8160498 (1994-12-01), None
Manabe Mitsuo
Oka Mitsuhiko
Birch & Stewart Kolasch & Birch, LLP
Blackman Rochelle
Fuji Photo Optical Co., Ltd.
Gray David M.
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