JPH08184879A - Screen frame switching mechanism - Google Patents

Abstract

PURPOSE: To provide a screen frame switching mechanism capable of vertically and horizontally changing the screen frame in a small space. CONSTITUTION: The screen frame switching mechanism is provided with a first screen frame prescribing member 6 prescribing a rectangular first screen frame FR1 and a second screen frame prescribing member 7 provided to be movable between retreating position where the member 7 is retreated in the first screen frame FR1 and a retreat position where the member 7 is retreated outside the side f the first screen frame FR1 and narrowing the first screen frame FR1 in a first direction parallel with a side, to prescribe a second screen frame, in the penetration position. A third screen frame for narrowing the first screen frame FR1 in a second direction perpendicular to the first direction is prescribed by the second and first screen frame prescribing members 7 and 6 which are moved in the middle stopping position between the penetration and retreat positions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for switching a screen frame of an optical device such as a field frame of a finder of a camera.

[0002]

2. Description of the Related Art As a switching mechanism of this type, for example, in Japanese Unexamined Patent Publication No. 4-113341, a common pinion gear is interposed between racks of a pair of screen frame defining members, and the pinion gear is rotated to rotate each pinion gear. It is disclosed that the screen frame defining member is driven symmetrically with respect to the optical axis. In addition, JP-A-6-82
No. 882, a pair of L-shaped screen frame defining members are arranged opposite to each other in a diagonal direction of the finder screen and engaged with a common cam plate, and the screen frame defining members are diagonally arranged in accordance with the operation direction of the cam plate. Driving in opposite directions is disclosed.

[0003]

In the conventional mechanism described above, the screen frame defining member is moved in the direction in which the screen frame is changed. Therefore, when the screen frame is changed in both the vertical direction and the horizontal direction, It is necessary to secure a moving space for the screen frame regulating member on the top, bottom, left and right around the viewfinder optical system.
It was a factor that hindered the miniaturization of the camera.

It is an object of the present invention to provide a screen frame switching mechanism capable of changing the screen frame vertically and horizontally in a space of only one direction.

[0005]

1 to 4 showing an embodiment, the invention of claim 1 defines a first screen frame FR1 which defines a rectangular first screen frame FR1. Member 6
And the entry position B that entered the first screen frame FR1,
The first screen frame FR is provided so as to be movable between a retracted position A that is retracted outside one side of the screen frame FR1 and is located at the entry position B.
1 is narrowed in the first direction (the vertical direction in FIG. 2B) parallel to one side to define the second screen frame FR2, and the second screen frame defining member 7 is provided. A third screen frame FR1 narrowed in the second direction orthogonal to the first direction by the second screen frame defining member 7 and the first screen frame defining member 6 that have moved to the intermediate stop position C between The above-described object is achieved by the screen frame switching mechanism configured so that the screen frame FR3 is defined. The invention according to claim 2 is applied to the screen frame switching mechanism according to claim 1, and defines the other side parallel to the one side of the first screen frame FR1 and is movable in the second direction.
b is provided on the first screen frame defining member 6, and the third screen defining portion 7b for defining one side of the third screen frame FR3 extending in the first direction at the intermediate stop position C is provided with the second screen frame defining member. The third screen defining portion 7 is provided at the end of the member 7 on the entry position B side.
When b is moved to the intermediate stop position C, the movable regulating portion 6b is moved to the center C of the screen as compared with the retracted position A and the entry position B.
Move to P side. The invention according to claim 3 is applied to the screen frame switching mechanism according to claim 2, and by the cam mechanism 15 provided between the second screen frame defining member 7 and the movable defining portion 6b of the first screen frame defining member 6. The movable regulating portion 6b is connected to the second screen frame regulating member 7
Displace according to the position of. The invention of claim 4 is claim 3
Applied to the screen frame switching mechanism, the cam mechanism 15 moves in association with the movement of the second screen frame defining member 7, and the movement direction is reversed at the intermediate stop position C as a boundary.
16b and the second cam 6 that reciprocates the movable regulating portion 6b in the second direction corresponding to the movement directions of the first cams 7c and 16b.
c, 16a. The invention of claim 5 relates to claims 1 to 4.
Any of the first screen frame defining member 6 and the second screen frame defining member 6 for switching the screen frame of the finder optical system provided separately from the photographing optical system of the camera.
The screen frame defining member 7 is arranged, and the second direction is set to a direction different from the alignment direction of the photographing optical system and the viewfinder optical system.

[0006]

In the invention of claim 1, the second screen frame defining member 7 is provided.
Is moved to the retreat position A, the first screen frame defining member 6
Defines the first screen frame FR1. The second screen frame defining member 7 moves the first screen frame F1 from one side of the first screen frame FR1.
When it moves toward R1 and reaches the intermediate stop position C, the first screen frame FR is moved by the first and second screen frame defining members 6 and 7.
The third screen frame F in which 1 is narrowed in the second direction orthogonal to the one side
R3 is defined. When the second screen frame defining member 7 moves to the entry position B, the first screen frame FR1 is narrowed in the first direction parallel to the one side to define the second screen frame FR2. In the invention of claim 2, when the third screen frame defining portion 7b moves from the retracted position A to the intermediate stop position C, the movable defining portion 6b of the first screen frame defining member 6 moves to the screen center CP side. The first screen frame FR1 is narrowed from both sides in the second direction. When the third screen frame defining portion 7b moves to the entry position B beyond the intermediate stop position C, the movable defining portion 6b causes the screen center C to move.
It moves away from P, and the second screen frame FR2 is enlarged in the second direction more than the third screen frame FR3. According to the invention of claim 3, the movable mechanism 6b is displaced by the cam mechanism 15 according to the position of the second screen frame regulating member 7. The movement of the movable regulating portion 6b can be arbitrarily set by changing the cam shape. In the invention of claim 4, the second screen frame defining member 7
The first cams 7c, 1 when the vehicle moves to the retreat position A side and the approach position B side with the intermediate stop position C as a boundary.
The moving direction of 6b is reversed, and the moving direction of the movable regulating portion 6b is switched by the second cams 6c and 16a in response to the change of the moving direction. According to the invention of claim 5, it is not necessary to provide a moving space for the screen frame defining members 6 and 7 in the direction in which the photographing optical system and the finder optical system are arranged, so that the distance between the finder optical system and the photographing optical system can be set small.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an outline of a real image type finder optical system of a camera to which the present invention is applied. 1 is a stop, 2 and 3 are objective lenses, and 4 is a subject image captured by the objective lenses 2 and 3 is inverted vertically and horizontally. A prism 5 is an eyepiece lens, and AX is an optical axis of the finder optical system. The finder optical system is provided separately from the taking optical system of the camera. Here, in this embodiment, three types of formats, that is, a first format, a second format in which the first format is shortened in the short side direction, and a third format in which the first format is shortened in the long side direction are taken It is intended for possible cameras.

In order to selectively display three types of screen frames within the field of view of the eyepiece lens 5 corresponding to the above format selection, in the present embodiment, the image plane (real image plane) of the objective lens 3 is displayed. The first screen frame defining member 6 and the second screen frame defining member 7 are provided behind them. And
The second screen frame defining member 7 moves in the long side direction of the screen frame (direction of arrow Y in FIG. 1) while being guided by the guide member 8, and the operation causes the first screen frame defining member 6 to move to the screen. By reciprocating in the long side direction of the frame, a first screen frame FR1 (FIG. 2A) compatible with the first format and a second screen frame FR2 (FIG. 3A) compatible with the second format. And a third screen frame FR3 corresponding to the third format (see FIG. 4).
Three types of screen frames of (a)) are defined in the finder optical path.

That is, as shown in FIG.
When the screen frame defining member 7 is in the retracted position A which is retracted to the side of the first screen frame defining member 6, the opening 6a of the first screen frame defining member 6 causes the first screen frame FR1 to enter the finder optical path. Is prescribed. As shown in FIG. 3A, when the second screen frame defining member 7 moves to the entry position B where it overlaps behind the first screen frame defining member 6 (on the prism 4 side), the second screen frame defining member 7 The second screen frame F through the opening 7a of
R2 is defined. Then, as shown in FIG.
The second screen frame defining member 7 is moved to the intermediate stop position C between the retreat position A and the entry position B, and the short side portion 7b is moved from the short side of the first screen frame FR1 by a predetermined amount δ to the screen center CP. When entering the side, the first screen frame defining member 6 causes the first screen frame F to
The short side portions 6b and 7b of both members 6 and 7 are moved to the second screen frame defining member 7 side by the predetermined amount δ from the time of defining R1.
(See FIG. 1), the first screen frame FR1 is narrowed in the long side direction to define the third screen frame FR3.

The screen centers CP of the screen frames FR1 to FR3 are all aligned with the finder optical axis AX. The screen frame defining members 6 and 7 are made of a dimming material (for example, a transmittance of 5).
0% ND filter). However, you may comprise by a light-shielding member. 2 to 4A each show a state in which the screen frame defining members 6 and 7 are viewed from the prism 4 side, and FIG. 2B is a plan view from the arrow b direction of FIG. A hatching area AR1 in FIG. 3A indicates a difference between the first screen frame FR1 and the second screen frame FR2, that is, a non-print area when the second format is selected, and FIG.
The hatched area AR2 in (a) shows the difference between the first screen frame FR1 and the third screen frame FR3, that is, the non-print region when the third format is selected.

Various configurations are conceivable as a mechanism for realizing the operations of the above-described screen frame defining members 6 and 7, but in the present embodiment, they are configured as follows. In the following,
In particular, when it is not necessary to distinguish the screen frames FR1 to FR3, they are simply expressed as the screen frame FR.

In order to reciprocate the second screen frame defining member 7 along the guide member 8, the rack 10 is integrally formed at the lower end of the second screen frame defining member 7 in this embodiment. It meshes with the pinion gear 11, and the pinion gear 11 is coaxially connected to the screen frame switching lever 12 (FIG. 1). When the screen frame switching lever 12 is rotated, the second screen frame defining member 7 moves to the retracted position A, the entry position B, or the intermediate stop position C described above according to the position. It should be noted that it is preferable that the screen frame switching levers 12 can be fixed at positions corresponding to the above three positions by a notch mechanism or the like. The screen frame switching lever 12 can be shared as the format signal selection lever described above. The size of the aperture immediately before the exposed surface of the film is made variable, and the size of the photographic screen recorded on the film itself is the above-mentioned first.
In a camera that can be changed corresponding to the third screen frame, the screen frame switching lever 12 and the aperture can be linked.

In order to reciprocate the first screen frame defining member 6 in the long side direction of the screen frame FR in association with the second screen frame defining member 7, a cam mechanism 15 is provided in this embodiment. There is. The cam mechanism 15 includes cam pins 6c, which are provided on the upper ends of the first and second screen frame defining members 6 and 7, respectively.
7c, a cam plate 16 having two cam grooves 16a, 16b into which these cam pins 6c, 7c fit, and a cam plate 16
And a fixed member (for example, a camera body) 17 and a tension spring 18 disposed between the fixed member and the fixed member 17. The cam plate 16 is rotatable about a fulcrum shaft 16c parallel to the short side of the screen frame FR, and is rotationally biased in the clockwise direction CW in FIG. 1 by the tensile force of the tension spring 18.

The cam grooves 16a and 16b of the cam plate 16 are provided with the first screen frame defining member 6 when the second screen frame defining member 7 moves between the retracted position A and the intermediate stop position C described above.
Moves to the opposite side of the second screen frame defining member 7, and when the second screen frame defining member 7 moves between the intermediate stop position C and the entry position B, the first screen frame defining member 6 is set to move in the same direction as the second screen frame defining member 7. That is, when the second screen frame defining member 7 is at the intermediate stop position C, the cam pin 7c is located at the bending point 160 of the cam groove 16b. When the second screen frame defining member 7 is located closer to the retracted position A than the intermediate stop position C, the cam pin 7c
Moves in the first linear portion 161, and as the second screen frame defining member 7 moves away from the retracted position A, the cam plate 16 rotates in the counterclockwise direction CCW around the fulcrum shaft 16c and the cam groove 16a. The cam pin 6c engaging with and the first screen frame defining member 6 integral with the cam pin 6c move to the opposite side with respect to the second screen frame defining member 7. When the second screen frame defining member 7 is located closer to the entry position B than the intermediate stop position C, the cam pin 7
c moves in the second straight line portion 162, and as the second screen frame defining member 7 approaches the entry position B, the cam plate 16 rotates in the clockwise direction CW around the fulcrum shaft 16c to move the first screen. The frame defining member 6 moves in the same direction as the second screen frame defining member 7. Note that FIG. 5 shows the positions of the second screen frame defining member 7 and the cam plate 16 in association with each other. As is clear from this figure, when the second screen frame defining member 7 moves from one of the retreat position A and the entry position B to the other,
The cam plate 16 and the first screen frame defining member 6 reciprocate once with the intermediate stop position C as a boundary.

As described above, in the present embodiment, three types of screen frames can be defined by simply reciprocating the second screen frame defining member 7 in the direction of the long side of the screen frame FR. It is not necessary to arrange the member for defining in the up and down direction of the screen frame FR so as to secure the moving space in the short side direction of the screen frame FR. Therefore, when it is applied to a camera in which a viewfinder optical system and a taking lens are stacked in the short side direction of the screen frame FR, it is not necessary to provide a moving space for the screen frame between the taking lens and the viewfinder optical system, and the taking lens is used. The parallax can be reduced by shortening the distance between the finder optical system and the finder optical system. Although the entire first screen frame defining member 6 is moved in the embodiment, only the short side portion 6b may be reciprocated. One of the short sides of the first screen frame FR1 may be defined by the short side portion 7b of the second screen frame defining member 7. Further, when the moving direction of the screen frame FR is the short side direction, the used space in the moving direction can be reduced as compared with the case where the screen frame is moved in the long side direction.

In the above embodiment, the short side portion 6b of the first screen frame defining member 6 is the movable defining portion, and the short side portion 7b of the second screen frame defining member 7 is the third screen frame defining portion. The cam pin 7c and the cam groove 16b form the first cam, and the cam pin 6c and the cam groove 1
6 a and the second cam respectively. As a mechanism for interlocking the two screen frame defining members, for example, a link mechanism may be used instead of the cam mechanism. The present invention can be applied not only to cameras but also to other optical devices. In the above embodiments, the screen frame switching mechanism of the finder has been described. However, it goes without saying that this screen frame switching mechanism can also be used as a switching mechanism for the aperture frame immediately before the film exposure surface.

[0018]

As described above, according to the present invention, the second
Since the screen frame can be switched in two directions only by moving the screen frame defining member between the retracted position set outside one side of the first screen frame and the entry position that has entered the first screen frame,
The screen frame can be changed vertically and horizontally in a space that is only in one direction. In particular, in a camera in which a finder optical system and a photographing optical system are provided separately, if the moving direction of the second screen frame defining member is set to a direction different from the alignment direction of both optical systems, the alignment directions of both optical systems will be Since it is not necessary to secure a moving space for the screen frame defining member, it is possible to reduce the parallax of the viewfinder with respect to the taking lens by bringing the viewfinder optical system close to the optical axis of the taking lens.
Particularly, in the invention of claim 2, the first screen frame is orthogonal to one side thereof by interlocking with the movable screen defining part of the first screen frame defining member and the third screen frame defining part of the second screen frame defining member. The third screen frame can be defined by narrowing from both sides in the second direction, and the third screen frame can be enlarged in the second direction when the second screen frame is selected. Further, in the invention of claim 3, the operation of the movable regulating portion can be arbitrarily set by changing the shape of the cam. According to the invention of claim 4,
By the first cam and the second cam, the moving direction of the movable regulating portion of the first screen frame regulating member can be switched according to the position of the second screen frame regulating member to change the screen frame in various ways. Claim 5
In the invention, the parallax of the viewfinder with respect to the taking lens can be reduced by setting the distance between the viewfinder optical system and the taking optical system small.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a finder optical system according to an embodiment of the present invention.

2A and 2B are diagrams showing a state in which a first screen frame is defined in the embodiment, FIG. 2A is a diagram showing a screen frame defining member seen from the prism side, and FIG. 2B is a view from a direction b in FIG. 2A. Plan view.

3A and 3B are diagrams showing a state in which a second screen frame is defined in the embodiment, FIG. 3A is a diagram showing a state in which the screen frame defining member is viewed from the prism side, and FIG. 3B is a view from a direction b in FIG. 3A. Plan view.

4A and 4B are diagrams showing a state in which a third screen frame is defined in the embodiment, where FIG. 4A is a plan view from the direction a in FIG. 4B, and FIG.
FIG. 6 is a diagram showing a state where the screen frame defining member is viewed from the prism side.

FIG. 5 is a diagram showing the positions of a second screen frame defining member and a cam plate in association with each other in the embodiment.

[Explanation of symbols]

 6 First screen frame defining member 6a Opening defining the first screen frame 6b Short side (movable defining part) 6c Cam pin 7 Second screen frame defining member 7a Opening defining second screen frame 7b Short side ( Third screen frame defining part) 7c Cam pin 15 Cam mechanism 16 Cam plates 16a, 16b Cam groove 16c Support shaft 18 Tension spring FR1 First screen frame FR2 Second screen frame FR3 Third screen frame

Claims (5)

[Claims] 1. A first screen frame defining member that defines a rectangular first screen frame, an entry position that enters the first screen frame, and a retract that is retracted outside one side of the first screen frame. A second screen frame defining member which is provided so as to be movable between the first position and the second position and is narrowed in the first direction parallel to the one side at the entry position. The first screen frame is moved in the first direction by the second screen frame defining member moved to an intermediate stop position between the entry position and the retracted position and the first screen frame defining member. A screen frame switching mechanism, characterized in that a third screen frame narrowed in a second direction orthogonal to each other is defined. 2. A movable defining portion that defines another side parallel to the one side of the first screen frame and is movable in the second direction is provided in the first screen frame defining member, and the intermediate stop is provided. The third screen defining portion for defining one side of the third screen frame extending in the first direction at the position is the second screen defining portion.
When the second screen frame regulating member is provided at the end of the screen frame regulating member on the entry position side and moves to the intermediate stop position, the movable regulation is provided more than at the retracted position and the entry position. The screen frame switching mechanism according to claim 1, wherein the unit moves toward the center of the screen. 3. A cam mechanism provided between the second screen frame defining member and the movable defining part of the first screen frame defining member causes the movable defining part to move to the second screen frame defining member. The screen frame switching mechanism according to claim 2, wherein the screen frame switching mechanism is displaced according to a position. 4. The first cam, which moves in association with the movement of the second screen frame defining member, and whose movement direction is reversed at the intermediate stop position, and the movement of the first cam. 4. A second cam that reciprocates the movable regulating portion in the second direction corresponding to the direction.
Screen frame switching mechanism described. 5. The first screen frame defining member and the second screen frame defining member are arranged so as to switch a screen frame of a finder optical system provided separately from a photographing optical system of a camera, and the second screen frame defining member is arranged. The screen frame switching mechanism according to any one of claims 1 to 4, wherein a direction is set to be different from a direction in which the photographing optical system and the finder optical system are arranged.