Photography – With viewfinder – Selective or adjustable viewfinder field
Reexamination Certificate
1998-11-30
2001-04-10
Gray, David M. (Department: 2851)
Photography
With viewfinder
Selective or adjustable viewfinder field
C396S380000, C396S435000
Reexamination Certificate
active
06215963
ABSTRACT:
This application is based on application No. H9-330288 filed in Japan, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a finder field frame switcher for cameras, and more particularly, to a finder field frame switcher in the advanced photo system having a plurality of image plane formats.
2. Description of the Prior Art
In the advanced photo system (hereinafter, referred to as APS) that have been commercialized in recent years, the image size format can be selected from among the following three types: a wide type (hereinafter, referred to as “H type”) with a length-to-width ratio of 9:16; a standard type (hereinafter, referred to as “C type”) with a length-to-width ratio of 2:3 in which, compared to the H type, the length is the same and the width is shorter; and a panorama type (hereinafter, referred to as “P type”) with a length-to-width ratio of 1:3 in which, compared to the H type, the width is the same and the length is shorter.
When an image size is selected by the user, it is necessary to switch the finder field frame. A conventional camera having a finder field frame switcher is arranged, for example, as shown in FIG.
1
. According to
FIG. 1
, a luminous flux A emanating from a subject and entering a camera
1
through a taking lens
2
is reflected at a reflecting mirror
3
and imaged at a focusing screen
4
.
In photographing, since the reflecting mirror
3
rotates so as to retreat to the vicinity of the focusing screen
4
and a shutter
12
is released for a predetermined time, the luminous flux A reaches a film
9
to expose the film
9
. In the APS, since image size information is recorded onto the film
9
by magnetic writing by use of a magnetic head (not shown) or by identification mark recording by use of a light emitting device (not shown), even if the film
9
is not shielded from light according to the image size format, the image size is decided based on the recorded image size information and printing onto photographic paper is performed.
On the other hand, in another system, for example, in a 135-type system, to switch between the standard image plane and the panoramic image plane, a field frame switching mechanism is necessarily provided in the front or in the rear of the shutter
12
.
In the rear of the focusing screen
4
on the optical path of the luminous flux A, a fixed field frame
5
having an H-type field frame and light interrupting wings
6
being rotatable are provided so that the light interrupting wings
6
rotate to switch between the H-type field frame and a P-type field frame. In the figure, the P-type field frame is selected when the light interrupting wings
6
are lying. The light interrupting wings
6
are also provided in positions parallel to the plane of the figure so as to switch between the H-type field frame and a C-type field frame. The image formed at the focusing screen
4
is reflected at a pentagonal Dach mirror
11
and enlarged by an eyepiece
8
so that the user can confirm the image of the desired field frame.
In order to automatically adjust exposure, a part (luminous flux A
2
) of the luminous flux A having been imaged at the focusing screen
4
is captured by the automatic exposure (AE) sensor
10
to detect brightness. Further describing with reference to a detailed view shown in
FIG. 2
, the focusing screen
4
and the AE sensor
10
are disposed so that the luminous flux A
2
to be captured by the AE sensor
10
is not interrupted by the light interrupting wing
6
when the light interrupting wing
6
is standing upright to form the H-type or the C-type field frame.
Subsequently, another conventional example will be described. As shown in
FIG. 3
, a finder field
21
which can be viewed by the user includes an image display portion
22
having an image plane corresponding to the H type, and information display portions
25
a
and
25
b
. When the C-type or the P-type field frame is selected, the focusing screen
4
(see subsequently-described
FIG. 4
) is shielded from light, so that a field
23
or
24
is displayed on the image display portion
22
.
On the information display portions
25
a
and
25
b
, information such as the aperture value, the shutter speed, the flash indicator and the in-focus indicator is displayed so that the user is informed of the information.
A method of displaying information on the information display portions
25
a
and
25
b
will be described with reference to FIG.
4
. In
FIG. 4
, the fixed field frame
5
and light interrupting wings
6
a
and
6
b
are disposed above the focusing screen
4
in the structure of the camera
1
similar to that of FIG.
1
. The light interrupting wings
6
a
and
6
b
are rotatable between a position that covers a field limiting portion
5
a
of the fixed field frame
5
and a position that is retreated from the field limiting portion
5
a
so that the field frame can be switched between the P type and the H type.
At a side of the focusing screen
4
, a display member
32
such as a transmission-type liquid crystal panel is attached to the camera
1
by a fixing member
34
. A luminous flux B from a backlight
33
is reflected at a mirror
31
to reach the eyepiece
8
together with the luminous flux A
1
of the image on the focusing screen
4
, so that information is displayed on the information display portion
25
a
in a lower part of the finder field
21
in the previously-described FIG.
3
.
Moreover, by a similar structure, switching between the C-type field frame and the H-type field frame can be performed by the light interrupting wings
6
a
and
6
b
. Further, by a similar structure, information can be displayed on the information display portion
25
b
in a side part of the finder field
21
.
In the arrangement in which the AE sensor
10
and the display member
32
are disposed in the vicinity of the focusing screen
4
as shown in
FIGS. 2 and 4
, the light interrupting wings
6
a
and
6
b
are disposed in positions that do not interrupt the luminous fluxes A
2
and B since the luminous fluxes A
2
and B used for obtaining information necessary for photographing cannot perform their functions if they are interrupted by the light interrupting wings
6
a
and
6
b
. However, such an arrangement requires a large space (L
1
and L
2
of
FIGS. 2 and 4
) in the rear of the focusing screen
4
on the optical path of the luminous flux A from the subject. This has been an obstacle to size reduction of the camera.
SUMMARY OF THE INVENTION
An object of the present invention is, in a camera having a field frame switching mechanism, to secure space for the members of the field frame switching mechanism and the switching path without increasing the size of the camera. More specifically, an object of the present invention is, in the arrangement in which the AE sensor
10
and the display member
32
are disposed in the vicinity of the focusing screen
4
, by reducing the overall size of the camera by providing a field frame switcher in which the optical path of the luminous flux A from the subject is shortened in the rear of the focusing screen by reducing the distance between the focusing screen
4
and an eyepiece
8
.
To achieve the above-mentioned object, according to the present invention, in a field frame switcher having a light interrupting wing capable of changing a field frame, the light interrupting wing crosses and interrupts a predetermined luminous flux path used for obtaining information necessary for photographing while the field frame is being changed.
According to this structure, the light interrupting wing is disposed close to the predetermined luminous flux path necessary for photographing and space in the camera can be reduced accordingly. When the field frame is switched, the light interrupting wing crosses the luminous flux path while moving to temporarily interrupt the luminous flux. However, since photographing has not been started yet when the field frame is switched, the luminous flux traveling on the luminous flux
Inoue Yoshiyuki
Kit Wong Ngai
Konishi Yoshito
Gray David M.
McDermott & Will & Emery
Minolta Co. , Ltd.
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