JP2000324370A - Single-lens reflex electronic still camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a single-lens reflex electronic still camera where an optical low pass filter is placed in a narrow space of a camera main body. SOLUTION: An optical low pass filter 500 is supported around a bearing hole 506 in a rocking enable way by inserting a 2nd spindle 308 of a 1st mirror 300 to the bearing hole 506. A guide shaft 508 of the optical low pass filter 500 is inserted to a guide groove 108 so as to be guided between a lower end 108A to an upper end 108B of the groove 108 along the guide groove 108. When the 1st mirror 300 is rocked to a 2nd jump-up position, the entire area of the optical low pass filter 500 is placed at a transmission position at which the entire area orthogonally faces an image pickup optical path L. When the 1st mirror 300 is rocked to the 1st position shown in Figure 1, the entire area of the optical low pass filter 500 is placed at a standby position that is displayed downward from the transmission position in the orthogonal direction of the image pickup optical path L.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a single-lens reflex electronic still camera.

[0002]

2. Description of the Related Art A single-lens reflex camera using a general silver halide film is capable of visually recognizing a subject image actually photographed on a film by switching a photographing optical path from a photographing lens to the film to a finder side by a mirror. Has advantages. A single-lens reflex electronic still camera in which the configuration of a single-lens reflex camera having such advantages is applied to an electronic still camera has been proposed. In such a single-lens reflex electronic still camera, a mirror and a shutter are provided in an imaging optical path of a photographic lens, similarly to a conventional single-lens reflex camera. The mirror is swingably provided between a first position for reflecting incident light from the photographing lens in the imaging optical path of the photographing lens and guiding the light to the finder optical system, and a second position retracted from the imaging optical path. I have. In addition, behind the mirror and the shutter, an image pickup device such as a CCD is provided on the image pickup optical path instead of the film. In the single-lens reflex electronic still camera having such a configuration, an optical low-pass filter for preventing occurrence of color moiré in the image sensor is provided on a photographing optical path in front of the image sensor. It is necessary to make the transmitted incident light incident on the image sensor. Further, in order to effectively prevent color moiré, it is preferable that the distance between the optical low-pass filter and the imaging device is short.

[0003]

However, in order to make the camera body as large as that of a normal single-lens reflex camera using a silver halide film, an imaging lens and a mirror must be provided in a limited space. , A shutter and an image sensor must be provided, which causes a problem that it is difficult to provide an optical low-pass filter as described below. That is, it is necessary to provide the optical low-pass filter so that the light incident surface and the light exit surface extend over the entire area of the imaging optical path in a state where the light incident surface and the light emitting surface are orthogonal to the imaging optical path. Here, when the optical low-pass filter is to be disposed in the space between the mirror and the shutter, if the mirror moves to the first position in the space between the mirror and the shutter which is almost the same as in the case of a normal single-lens reflex camera, However, the upper part of the rear surface of the mirror and the upper end of the optical low-pass filter located behind the mirror physically interfere with each other, so that the optical low-pass filter cannot be provided. Further, even if an optical low-pass filter is to be disposed between the shutter and the image sensor, the optical low-pass filter is disposed because the space between the shutter and the image sensor is as small as that of a normal single-lens reflex camera. It is difficult. The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a single-lens reflex electronic still camera capable of disposing an optical low-pass filter in a narrow space of a camera body. It is in.

[0004]

According to the present invention, there is provided a first mirror, an optical low-pass filter, a shutter, and an image sensor, which are arranged in the imaging optical path in that order.
The upper end of the camera body is swingably supported, the first position reflects the incident light guided into the imaging optical path and guided to the finder optical system, and is retracted from the imaging optical path. An optical low-pass filter, a single-lens reflex electronic still camera that oscillates to a second position leading to an image sensor, wherein an upper end of the optical low-pass filter is placed in the first position.
Connecting means is provided for connecting the lower end of the optical low-pass filter to the camera body while being connected to the upper end of the mirror, and the connecting means is provided when the first mirror is swung to the second position. When the first mirror is swung to the first position, the filter is positioned below the transmission position in the direction orthogonal to the imaging optical path when the first mirror is swung to the first position. It is configured to be located at the displaced standby position. Further, in the present invention, the connection between the optical low-pass filter and the first mirror by the connecting means may be such that the left and right sides of the upper end of the optical low-pass filter and the left and right sides of the upper end of the first mirror can swing. Is characterized by being connected to the Further, the present invention is characterized in that a bearing hole and a support shaft that is swingably inserted into the bearing hole are used for connecting the optical low-pass filter and the first mirror by the connecting means.
Further, according to the present invention, the connecting means includes a support piece projecting upward at left and right sides of the optical low-pass filter,
The connection between the optical low-pass filter and the first mirror by the connecting means is performed by the support piece being swingably supported on the left and right sides of the upper end of the first mirror via a support shaft. It is characterized by being. Further, the invention is characterized in that the connection between the optical low-pass filter and the camera body by the connection means is made between the left and right side portions at the lower end of the optical low-pass filter and the camera body.

Further, according to the present invention, a guide groove and a guide shaft movably disposed along the guide groove are used for connecting the optical low-pass filter to the camera body by the connecting means. Features. Also, in the present invention, the guide groove is provided at a camera body portion on both left and right sides of the imaging optical path, and the guide shaft is protruded from left and right sides of a lower end of the optical low-pass filter toward left and right sides. It is characterized by the following. Further, in the present invention, the optical low-pass filter includes a filter body having a rectangular plate shape,
A filter side plate attached to each of left and right sides of the filter body, an upper portion of the filter side plate protruding above an upper portion of the filter body, and a connection between the optical low-pass filter and the first mirror is formed by the filter. The upper part of the side plate is swingably supported by the left and right side parts of the upper end of the first mirror. Also,
According to the present invention, a guide shaft is provided at a lower end of each of the filter side plates toward the left and right sides, and the optical low-pass filter and the camera body are connected to each other by a guide groove formed in the camera body. It is characterized by being movably inserted.

Further, in the present invention, the optical low-pass filter is configured to be substantially orthogonal to the imaging optical path in the imaging optical path between the first mirror and the imaging device in a state where the optical low-pass filter is located at the standby position. It is characterized by being. Also,
The present invention is a photographing lens for guiding incident light to the imaging optical path,
An autofocus sensor for performing the focusing operation of the photographing lens and a second mirror are provided, the first mirror is a half mirror, and the second mirror is disposed on a back surface of the first mirror. The first mirror is located at an operating position for guiding a part of the incident light transmitted through the first mirror to the autofocus sensor in a state where the first mirror is swung to the first position. The apparatus is characterized in that it is configured to be located at a non-operation position where it is retracted from the imaging optical path while being swung to the second position. Further, the present invention is characterized in that the image pickup device performs an image pickup operation based on the incident light transmitted through the optical low-pass filter, thereby preventing occurrence of color moiré in the image pickup device. I do. Further, the invention is characterized in that the image pickup device is constituted by a CCD.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a single-lens reflex electronic still camera according to an embodiment of the present invention.
FIG. 2 is an explanatory view showing a state where the first mirror is moving to a position, FIG. 2 is an explanatory view showing a state where the first mirror is moving to an intermediate position between the first position and the second position in the embodiment, and FIG. FIG. 4 is an explanatory view showing a state in which the first mirror is moved to a second position in the embodiment, and FIG. 4 is an external perspective view showing a configuration of an optical low-pass filter. First, the configuration of a single-lens reflex electronic still camera will be described with reference to FIGS. The single-lens reflex electronic still camera 1000 of the present embodiment includes a camera body 100, a finder optical system 200, a first mirror 300, a second mirror 400, and an optical low-pass filter 50.
0, an image sensor 600, an automatic focus sensor 700, and the like.

The camera body 100 includes a front wall (not shown), left and right side walls (not shown) connected to the left and right sides of the front wall, an upper wall 101 connecting upper ends of the front wall and the left and right side walls, and left and right side walls. And a bottom wall 106 connecting the front wall, the left and right side walls, and the lower end of the rear wall 104 to form a housing space, and the first mirror 30 is provided in the housing space.
0, a second mirror 400, an optical low-pass filter 500,
An accommodation space for accommodating the image sensor 600, the autofocus sensor 700, and the like is formed. A lens mount 106 is provided on the front wall of the camera body 100, and a photographic lens (not shown) is attached to the lens mount 106.

The finder optical system 200 includes a camera body 1
00, the prism 202, the lens group 20
4. It has a finder window 206 and the like.
A mirror box (not shown) is arranged inside the camera body 100, and a first mirror 300, a second mirror 400, and an optical low-pass filter 500 are arranged in this mirror box along the imaging optical path L in this order. I have. An image sensor 600 composed of a CCD is arranged on the image pickup optical path L behind the mirror box, that is, near the back of the camera body 100.

The first mirror 300 includes a mirror main body 302 composed of a rectangular plate-shaped half mirror, a mirror side portion 304 extending along left and right sides thereof, and two mirror side portions 3.
A first support shaft 306 protruding left and right from the upper end of the first support member 04, and a first support shaft 3 of the two mirror side portions 304.
And a second support shaft 308 protruding from the lower part of the reference numeral 06 toward the left and right sides.

[0011] The first support shaft 306 is a first support of the mirror box.
The second support shaft 308 is swingably supported by an unillustrated bearing hole provided at a location facing the left and right of the mirror 300.
It is inserted into a bearing hole 506 of an optical low-pass filter 500 described later. Then, the first mirror 300 makes an angle of 45 degrees with respect to the imaging optical path L by a mirror driving mechanism (not shown), that is, reflects the incident light guided to the imaging optical path L by 90 degrees in the imaging optical path L and reflects it by 90 degrees. A first position (FIG. 1) leading to the finder optical system 200 is parallel to the imaging optical path L,
That is, the incident light is retracted from the imaging optical path L, and the incident light is transmitted through the optical low-pass filter 500 so that the imaging device 600
To the second position (FIG. 3) which leads to the position shown in FIG.

The second mirror 400 is provided so as to be interlocked with the swing of the first mirror 300 by a known means. The upper end of the second mirror 400 on the rear side of the first mirror 300 is pivotally connected to the mirror side of the first mirror 300. The portion 304 is swingably supported. Then, the second mirror 400 detects a part of the incident light transmitted through the first mirror 300 in a state where the first mirror 300 is swung to the first position.
The first mirror 300 is positioned at an operating position (FIG. 1) leading to
Is swung to the second position and the imaging optical path L
It is configured to be located at a non-operation position (FIG. 3) retracted from the vehicle.

As shown in FIG. 4, an optical low-pass filter 500 includes a filter body 502 having a rectangular plate shape,
Two filter side plates 504 (corresponding to the left and right sides of the optical low-pass filter in the claims) extending along the left and right sides of the filter body 502, and an upper part of the filter body 502 at the upper end of each filter side plate 504 502A
And a support piece 504A protruding upward. Each support piece 504A is provided with a bearing hole 506 having an axial center extending in the left-right direction.
A guide shaft 508 protrudes from the lower end of the left and right sides.

As shown in FIG. 1, the optical low-pass filter 500 is provided on the back side of the first mirror 300. That is, the optical low-pass filter 500
Since the bearing hole 506 is inserted through the second support shaft 308 of the first mirror 300, it is swingably supported about the bearing hole 506. In addition, a portion sandwiching the left and right sides of the mirror box of the camera body 100, that is, a portion sandwiching the left and right sides of the lower end of the optical low-pass filter 500,
An unillustrated fixing member is provided, and a slot-like guide groove 108 that is inclined upward as approaching the taking lens is formed at a position of the fixing member facing the guide shaft 508 of the optical low-pass filter 500. Then, the guide shaft 508 of the optical low-pass filter 500 is movably inserted into the guide groove 108 so that the guide groove 108
Along the space between the lower end 108A and the upper end 108B. That is, the guide shaft 508 of the optical low-pass filter 500 is disposed so as to be movable along the guide groove 108.

The optical low-pass filter 500 includes a bearing hole 5
06 is inserted into the support shaft 308 of the first mirror 300, so that the upper end of the optical low-pass filter 500 is connected to the first mirror 300. In the optical low-pass filter 500, the lower end of the optical low-pass filter 500 is connected to the camera body 100 because the guide shaft 508 is inserted into the guide groove 108. That is, the connection means in the present invention is constituted by the bearing hole 506 of the optical low-pass filter 500, the support shaft 506 of the first mirror 300, the guide shaft 508 of the optical low-pass filter 500, and the guide groove 108 of the fixing member.

When the first mirror 300 is swung to the second position, as shown in FIG.
The optical low-pass filter 500 is configured so that its entire area, that is, the entire area of the filter body 502 is located at a transmission position facing orthogonally to the imaging optical path L. Also, as shown in FIG. 1, when the first mirror 300 is swung to the first position, the first mirror 300 is positioned at the standby position displaced downward in the direction orthogonal to the imaging optical path L from the transmission position. It is configured. Also, the optical low-pass filter 500
The bearing hole 506 is formed in the upper portion 502A of the filter body 502.
Since the second support shaft 308 is provided on the support piece 504A protruding upward and is swingably supported by inserting the second support shaft 308 into the bearing hole 506, as shown in FIG. When the filter 500 is located at the standby position, the upper part 502A of the filter body 502 is placed on the first mirror 304.
It does not interfere with the location.

As shown in FIG. 3, the image sensor 60
Reference numeral 0 denotes an incident light which is disposed so that the entire area of the imaging surface 602 faces orthogonally to the imaging optical path L, and which is incident on the imaging surface 602 through the imaging lens and transmitted through the filter body 502 of the optical low-pass filter 500. Is formed so as to form a subject image formed by the camera.

As shown in FIG. 1, the autofocus sensor 700 includes a first mirror 300, a second mirror 400,
It is disposed below a mirror box that houses the optical low-pass filter 500. Then, by detecting a part of the incident light transmitted through the first mirror 300 located at the first position and guided by the second mirror 400, a detection signal necessary for performing a focusing operation of the photographing lens is generated. It is configured to supply to an unillustrated automatic focus adjustment mechanism.

Although not shown in FIGS. 1 to 3, a shutter for controlling the passage of incident light to the image sensor 600 is provided in a space 110 between the optical low-pass filter 500 and the image sensor 600. ing. In the present invention, the type of the shutter is not particularly limited. That is, the optical low-pass filter 500 is disposed in a narrow space between the first mirror 300 and the shutter.

Next, the operation of the single-lens reflex electronic still camera 1000 configured as described above will be described. First, as shown in FIG.
The mirror 300 is located at the first position, and the second mirror 400 is located at the operating position. Further, the shutter is closed. That is, the first mirror 300 faces the imaging optical path L and reflects the incident light guided to the imaging optical path L by the imaging lens by 90 degrees, thereby guiding the incident light to the finder optical system 200. The incident light guided to the finder optical system 200 is reflected by the prism 202, passes through the lens group 204, and reaches the finder window 206. Thus, the photographer can visually recognize the subject image actually photographed by the photographing lens by looking at the finder window 206.

At this time, part of the incident light that has passed through the first mirror 300 is reflected by the second mirror 400 and guided to the auto-focus sensor 700. Auto focus sensor 700
Supplies a detection signal necessary for performing a focusing operation of the taking lens based on a part of the incident light received from the second mirror 400 to an unillustrated automatic focus adjustment mechanism. In the optical low-pass filter 500, since the first mirror 300 is swung to the first position, the guide shaft 508 is
8 is located at a standby position in contact with the lower end 108A. In this state, the filter body 502 of the optical low-pass filter 500 is held in a state substantially orthogonal to the imaging optical path L, but below the transmission position extending over the entire area of the imaging optical path L in the direction orthogonal to the imaging optical path L. It has shifted.

Here, when the photographer depresses a shutter switch (not shown), a mirror driving mechanism (not shown) operates to move the first mirror 300 from the first position shown in FIG. 1 to that shown in FIG. Via the intermediate position shown in FIG.
Rock to the position. While the first mirror 300 is swung from the first position to the second position, the second mirror 400 is swung about the pivot 402 to the inoperative position retracted from the imaging optical path L. When the first mirror 300 is swung from the first position to the second position about the first support shaft 306, the optical low-pass filter 500 causes the second support shaft 308 inserted into the bearing hole 506 at the upper end thereof. , And the guide shaft 508 at the lower end is guided along the guide groove 108 from the lower end 108A to the upper end 108B. At this time, the filter body 50 of the optical low-pass filter 500
2 is moved upward and forward while maintaining a state orthogonal to the imaging optical path L. First mirror 3
When 00 reaches the second position, the optical low-pass filter 500
The guide shaft 508 at the lower end thereof abuts on the upper end 108B of the guide groove 108, and the filter main body 502 is located at a transmission position where the entire area faces orthogonally to the imaging optical path L.

When the shutter is opened in this state, the incident light guided to the imaging optical path L by the photographing lens and passing through the filter body 502 of the optical low-pass filter 500 passes through the opened shutter and passes through the opened shutter. An object image is formed on the imaging surface 602 of the camera, and this object image is recorded as image data on a recording medium (not shown) through a known process. Therefore, occurrence of color moiré in the image sensor 600 is prevented.

After the shutter is closed again, the first mirror 300 is swung from the second position to the first position via the intermediate position by a mirror driving mechanism (not shown). While the first mirror 300 is swung from the second position to the first position, the second mirror 400 is swung about the pivot 402 from an inoperative position to an operating position facing the imaging optical path L. When the first mirror 300 is swung from the second position to the first position about the first support shaft 306, the optical low-pass filter 500
Is the second support shaft 30 inserted in the bearing hole 506 at the upper end thereof.
8, the guide shaft 508 at the lower end is guided along the guide groove 108 from the upper end 108B to the lower end 108A. At this time, the filter main body 502 of the optical low-pass filter 500 is moved downward and backward in the direction orthogonal to the imaging optical path L while maintaining a state orthogonal to the imaging optical path L.

When the first mirror 300 reaches the first position, the optical low-pass filter 500 moves the guide shaft 50 at its lower end.
8 is located at a standby position in contact with the lower end 108A of the guide groove 108, and is returned to the initial state described above.

As described above, according to the present embodiment,
The optical low-pass filter 500 includes a filter main body 50 that is driven by the first mirror 300 being swung to the second position.
2 is located at the transmission position facing the imaging optical path L orthogonally, and the standby position displaced downward in the direction orthogonal to the imaging optical path from the transmission position due to the first mirror 300 being swung to the first position. Is located. Therefore, the first
Even when the space between the mirror 300 and the shutter is as small as that of a normal single-lens reflex camera, the optical low-pass filter 500 can be connected to the first mirror 300.
It is possible to dispose it in a narrow space between the first mirror 300 and the shutter without causing interference. If the space between the first mirror 300 and the shutter is as small as that of a normal single-lens reflex camera, the optical low-pass filter is mounted on the camera body such that the entire area faces orthogonally to the imaging optical path L. Even if the optical low-pass filter 100 is to be fixed, the upper part of the first mirror 300 swinging between the first position and the second position and the optical low-pass filter interfere with each other, and it is impossible to dispose the optical low-pass filter. Therefore, according to the present invention, it is possible to provide a single-lens reflex electronic still camera in which an optical low-pass filter can be provided in a narrow space of a camera body.

In the present embodiment, the guide shaft 508 is provided at the lower end of the optical low-pass filter 500 and the guide groove 108 is provided at the camera body 100. On the contrary, the guide groove is provided at the lower end of the optical low-pass filter 500. The camera body 100 may be provided with a guide shaft. In the present embodiment, a bearing hole 506 is provided at the upper end of the optical low-pass filter 500 (the support piece 504A of the filter side plate 504), and the first support shaft 308 inserted into the bearing hole 506 is provided at the upper end of the first mirror 300. However, on the contrary, a support shaft is provided at the upper end of the optical low-pass filter 500, and the first mirror 3 is provided.
A bearing hole into which this support shaft is inserted may be provided at the upper end of the 00. In the present embodiment, the second mirror 400 is
Although the mirror 300 is provided so as to be swingable, a configuration in which the second mirror is not provided may be used.

[0028]

As is clear from the above description, the present invention
A first mirror, an optical low-pass filter, a shutter, and an image sensor, which are arranged in that order on the imaging optical path, wherein the first mirror is pivotally supported at its upper end by a camera body and faces the imaging optical path. A single lens that oscillates between a first position where the incident light guided to the imaging optical path is reflected and guided to the finder optical system and a second position where the incident light is retracted from the imaging optical path and reaches the optical low-pass filter and the image sensor. A reflex-type electronic still camera, wherein a connecting means for connecting an upper end of the optical low-pass filter to an upper end of the first mirror and connecting a lower end of the optical low-pass filter to a camera body is provided; The first mirror is the second mirror
When the optical low-pass filter is swung to the position, the optical low-pass filter is positioned at a transmission position where the entire area faces orthogonally to the imaging optical path, and when the first mirror is swung to the first position, the optical low-pass filter transmits the light. It is configured to be located at a standby position displaced downward in a direction orthogonal to the imaging optical path from a position. Therefore, the optical low-pass filter is located at the transmission position where the entire area of the optical low-pass filter is orthogonal to the imaging optical path due to the first mirror being swung to the second position, and the first mirror is swung to the first position. By being moved, it is located at the standby position displaced downward in the direction orthogonal to the imaging optical path from the transmission position.
Therefore, the optical low-pass filter can be disposed behind the first mirror without interfering with the first mirror, and the optical low-pass filter can be disposed in a narrow space.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a state in which a first mirror is moving to a first position according to an embodiment of a single-lens reflex electronic still camera of the present invention.

FIG. 2 is an explanatory diagram showing a state in which a first mirror has moved to an intermediate position between a first position and a second position in the embodiment.

FIG. 3 is an explanatory diagram showing a state where a first mirror is moving to a second position in the embodiment.

FIG. 4 is an external perspective view illustrating a configuration of an optical low-pass filter.

[Explanation of symbols]

 Reference Signs List 1000 single-lens reflex electronic still camera 100 camera body 200 finder optical system 300 first mirror 400 second mirror 500 optical low-pass filter 600 imaging device L imaging optical path

Claims (5)

[Claims] 1. A first optical system arranged in an imaging optical path in that order.
A mirror, an optical low-pass filter, a shutter, and an image sensor, wherein the first mirror is pivotally supported at its upper end by a camera body, reflects the incident light that faces the imaging optical path, and is guided to the imaging optical path. A single-lens reflex electronic still camera swinging between a first position leading to a finder optical system and a second position retracting from the imaging optical path and allowing the incident light to reach the optical low-pass filter and the imaging device, wherein the optical low-pass Connecting means for connecting the upper end of the filter to the upper end of the first mirror and connecting the lower end of the optical low-pass filter to the camera body, wherein the first mirror is swung to the second position. When the optical low-pass filter is positioned at a transmission position where the entire area faces orthogonally to the imaging optical path, and the first mirror is swung to the first position. Single-lens reflex electronic still camera, wherein the transmission position is configured to be positioned at the standby position displaced downward in the orthogonal direction of the imaging optical path than it. 2. An optical low-pass filter and the first mirror are connected by the connecting means so that the left and right sides of the upper end of the optical low-pass filter and the left and right sides of the upper end of the first mirror can swing. 2. The single-lens reflex electronic still camera according to claim 1, wherein the electronic still camera is connected. 3. The camera according to claim 1, wherein the connection of the optical low-pass filter to the camera body by the connecting means is performed between the left and right sides of a lower end of the optical low-pass filter and the camera body. 2. A single-lens reflex electronic still camera according to 2. 4. A guide groove and a guide shaft movably disposed along the guide groove are used for connecting the optical low-pass filter to the camera body by the connecting means. Item 1. A single-lens reflex electronic still camera according to item 1, 2 or 3. 5. The optical low-pass filter is configured to be substantially orthogonal to the imaging optical path in the imaging optical path between the first mirror and the imaging device in a state where the optical low-pass filter is located at the standby position. The single-lens reflex electronic still camera according to claim 1.