JPH08160497A - Picture frame switching mechanism - Google Patents

Abstract

PURPOSE: To provide a picture frame switching mechanism capable of easily coping with many kinds of picture frames. CONSTITUTION: As for the picture frame switching mechanism for changing the relative positions of plural picture frame defining members 7 to 10 in a plane orthogonally crossed with the optical axis AX of an optical system and switching the picture frame to plural kinds of frames, the mechanism is provided with a driving member 11 for driving some picture frame defining members 7 and 8 among plural picture frame defining members 7 to 10 and linking mechanisms 13, 14 and 16 to 19 for linking other picture frame defining members 9 and 10 with the operations of the picture frame defining members 7 and 8 in accordance with a prescribed condition.

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 above-mentioned conventional mechanism, all the screen frame defining members are directly driven by a common driving member (pinion gear, cam plate, etc.), so that the driving direction of the screen frame defining member is increased. The degree of freedom in designing the correspondence between the change of the screen frame and the change of the screen frame is small, and the change of the screen frame is monotonous. That is, when the screen frame defining member is driven in the diagonal direction of the screen, the screen frame only expands and contracts vertically and horizontally at a constant rate of change according to the inclination of the moving direction. When driving to either one of them, the screen frame does not change to the other. Therefore, when the number of types of screen frames increases, it becomes necessary to separately provide the screen frame defining member and its driving means according to the types of screen frames, which complicates the mechanism.

An object of the present invention is to provide a screen frame switching mechanism which can easily support a large number of screen frames.

[0005]

1 and 2, which show an embodiment, the invention of claim 1 provides a plurality of screen frames in a plane orthogonal to the optical axis AX of the optical system. The present invention is applied to a screen frame switching mechanism in which the relative positions of the regulating members 7 to 10 are changed and the screen frame can be switched to a plurality of types. And
Of the plurality of screen frame defining members 7 to 10, a driving unit 11 that drives a part of the screen frame defining members 7 and 8 and another screen frame defining member for the operation of the screen frame defining members 7 and 8 9, 1
Interlocking means 13, 1 for interlocking 0 according to a predetermined condition
4, 16 to 19 are provided to achieve the above-mentioned object. In the invention of claim 2, as the plurality of screen frame defining members 7 to 10, first defining members 7 and 8 that define the screen frame in a first direction (direction of arrow A) orthogonal to the optical axis AX of the optical system,
A second defining member 9, which defines a screen frame in a second direction (direction of arrow B) orthogonal to both the optical axis AX and the first direction,
10 is provided, and the driving means 11 includes the first defining member 7,
8 is provided to reciprocate in the first direction, and the interlocking means 1
3, 14, 16 to 19 are second defining members 9, when the first defining members 7 and 8 are closer to the optical axis AX than the first reference position.
10 is held at a distance beyond the second reference position with respect to the optical axis AX, and when the first defining members 7, 8 are away from the first reference position with respect to the optical axis AX, the second defining members 9, 10 are moved to the second reference position. It is closer to the optical axis AX than the position. In the invention of claim 3, when the first defining member 7, 8 is further than the first reference position, the position of the screen frame in the first direction is fixed to a position corresponding to the first reference position,
A reference frame defining member 6 is provided to fix the position of the screen frame in the second direction to a position corresponding to the second reference position when the second defining members 9 and 10 are further than the second reference position. In the invention of claim 4, the first defining members 7 and 8 and the second defining members 9 and 10 are provided.
Are provided symmetrically with respect to the optical axis AX, respectively.
The driving means 11 reciprocally drives the pair of first defining members 7 and 8 in opposite directions in the first direction. In the invention of claim 5, as the interlocking means, the cam mechanisms 13, 14, 16 to 1 in which the first defining member 7 is the driving joint and the second defining members 9 and 10 are the follower joints.
9 was used. In the invention of claim 6, the optical system is a viewfinder optical system provided separately from the photographing optical system of the camera.

[0006]

According to the first aspect of the invention, when some of the screen frame defining members 7 and 8 are driven, the other screen frame defining members 9 and 10 are interlocked with each other according to a predetermined condition. Other screen frame defining members 9, 10
Is not directly driven by the driving means 11, the other screen frame defining members 9, 8 in a direction different from some screen frame defining members 7, 8.
A wide variety of screen frames can be accommodated by simply changing the configuration of the interlocking means 13, 14, 16-19, such as driving 10 or applying different amounts of movement to the screen frame defining members 7-10. In the invention of claim 2, when the first defining member 7, 8 is moved to the optical axis AX side from the first reference position, the second defining member 9, 10 is held further than the second reference position, and the screen frame becomes the first frame. Narrowed in the direction (Fig. 3). On the contrary, when the first defining member 7, 8 is moved beyond the first reference position, the second defining member 9, 10 moves closer to the optical axis AX than the second reference position, and the screen frame is narrowed in the second direction. (Fig. 4). The first defining member 7 at the first reference position,
8 and the second defining members 9 and 10 at the second reference position can define another screen frame. In the invention of claim 3, when the first defining member 7, 8 is further than the first reference position and the second defining member 9, 10 is further than the second reference position, the reference frame defining member 6 corresponds to each reference position. The screen frame FR1 is defined by the position. When the first defining members 7 and 8 move from this state to the optical axis AX side in the first direction, the screen frame position in the second direction is fixed at the same position by the reference frame defining member 6, and the screen frame moves in the first direction. It is narrowed (Fig. 3). On the contrary, when the second defining members 9 and 10 move to the optical axis AX side in the second direction, the screen frame position in the first direction is fixed at the same position by the reference frame defining member 6, and the screen frame moves in the second direction. It is narrowed (Fig. 4). According to the invention of claim 4,
The screen frame can be switched while maintaining the symmetry with respect to the optical axis AX. In the invention of claim 5, the interlocking condition between the first defining member 7, 8 and the second defining member 9, 10 can be arbitrarily set by changing the cam shape. In the invention of claim 6, various kinds of screen frames can be displayed in the viewfinder of the camera.

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 EMBODIMENTS An embodiment of the present invention will be described below 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. The prism 5 is an eyepiece lens.
The finder optical system is provided separately from the taking optical system of the camera. Here, in the present embodiment, a signal designating a format (aspect ratio) at the time of printing can be recorded on a recording medium such as film, and the format is the first format and the first format is a first format shortened in the long side direction. Two
It is assumed that the camera is capable of switching between three formats, a format and a third format in which the first format is shortened in the short side direction.

In order to selectively display three types of screen frames in the field of view of the eyepiece lens 5 corresponding to the selection of the above three types of formats, one reference frame defining member 6 and four reference frame defining members 6 are provided. The screen frame defining members 7, 8, 9, 10 and the objective lens 2,
3 is disposed in the vicinity of the image plane (real image plane). The reference frame defining member 6 is formed by forming an opening 6b in which the aspect ratio is the same as that of the above-described first format in a light shield 6a having a substantially rectangular shape. On the other hand, the screen frame defining members 7 to 10 are screen frames defined by the openings 6 b of the reference frame defining member 6 (hereinafter,
This is called the first screen frame. ) Is narrowed in the long side direction (direction of arrow A) and in the short side direction (direction of arrow B), both of which are made of a light attenuating material (for example, an ND filter having a transmittance of about 10%). Instead of the dimming member, a sheet-shaped light shielding material having a transmittance of 0% may be used.

As shown in FIG. 2, screen frame defining members 7 and 8
And the screen frame defining members 9 and 10 are respectively the first screen frame F.
They are arranged symmetrically with respect to the center CP of R1. The center CP coincides with the optical axis AX of the finder optical system shown in FIG. The left and right screen frame defining members 7 and 8 are supported by a support member (not shown) so as to be able to advance and retract from the short side of the first screen frame FR1, and the upper and lower screen frame defining members 9 and 10 are provided from the long side of the first screen frame FR1. It is supported so that it can move forward and backward. The left and right screen frame defining members 7 and 8 have arm portions 7a and 8a extending laterally of the first screen frame FR1, and racks 7b and 8b are formed at the opposing portions of these arms 7a and 8a. Rack 7
b and 8b mesh with a common pinion gear 11, and this pinion gear 11 is rotationally driven by a screen frame switching lever 12 (FIG. 1). The screen frame switching lever 12 can be shared as the format signal selection lever described above.

A cam surface 1 is provided on the upper and lower ends of the screen frame defining member 7.
3, 14 are formed. By the compression springs 16 and 17 arranged between the screen frame defining members 9 and 10 and the fixing member (for example, the camera body) 15, the screen frame defining members 9 and 10 are provided.
Is always urged toward the center CP of the first screen frame FR1. By this biasing force, the cam pins 18 and 19 implanted in the screen frame defining members 9 and 10 are pressed against the cam surfaces 13 and 14, and the positions of the screen frame defining members 9 and 10 are defined. The cam surfaces 13 and 14 are formed symmetrically in the short side direction of the first screen frame FR1, and are inclined toward the first screen frame FR1 toward the center of the screen frame defining member 7, and from both ends thereof. It has flat surfaces 13b, 13c, 14b, 14c extending parallel to the moving direction of the screen frame defining member 7.

In the above structure, the screen frame switching lever 1
When 2 is held in the middle of the movement range, the screen frame defining members 7 and 8 are retracted to the left and right of the first screen frame FR1 as shown in FIG. 2, and the cam pins 18 and 19 are flat surfaces 13b of the cam surfaces 13 and 14. , 14b, and the screen frame defining members 9 and 10 are retracted above and below the first screen frame FR1. In this state, the first screen frame FR1 is displayed within the field of view of the eyepiece lens 5. When the screen frame switching lever 12 is operated so that the pinion gear 11 rotates clockwise from the position shown in FIG. 2, the screen frame defining members 7 and 8 enter the first screen frame FR1 as shown in FIG. A dimming area (hatched area in the figure) AR1 is generated at the left and right ends of the first screen frame FR1 and the second screen frame FR2 is provided inside thereof.
Is prescribed. The relationship between the operation amount of the screen frame switching lever 12 and the movement amounts of the screen frame defining members 7 and 8 is set so that the aspect ratio of the second screen frame FR2 matches the above-described second format.

On the other hand, when the screen frame switching lever 12 is operated so that the pinion gear 11 rotates counterclockwise from the position shown in FIG. 2, the screen frame defining members 7 and 8 move the first screen frame FR1 as shown in FIG. From the cam pin 1
8 and 19 are flat surfaces 13 via slopes 13a and 14a.
c, 14c. As a result, the screen frame defining members 9 and 10 enter the first screen frame FR1 and the first screen frame F
Dimming area (hatched area in the figure) AR2 at the top and bottom of R1
Occurs, and the third screen frame FR3 is defined inside thereof. The flat surfaces 13c of the cam surfaces 13 and 14 are arranged so that the aspect ratio of the third screen frame FR3 matches the above-described third format.
The position of 14c is set.

According to the above-described embodiment, the screen frame defining members 9 and 10 can be simply changed by changing the shapes of the cam surfaces 13 and 14 without changing the movement direction and the moving amount of the screen frame defining members 7 and 8. It is possible to give various movements to, and easily adapt to various screen frames.

If the transmittances of the screen frame defining members 7 to 10 are properly set, the first screen frame FR in the state of FIG.
1 and the second screen frame FR2, the first screen frame FR1 and the third screen frame FR3 in the state of FIG. 4 can be simultaneously checked in the finder screen. When such a need is not necessary, the screen frame defining members 7 to 10 may be made of a light shielding material. As shown in FIG. 5, the reference frame defining member 6 may be omitted and three or more types of screen frames may be defined only by the screen frame defining members 7 to 10. The screen frame switching lever 12 includes a first screen frame FR1, a second screen frame FR2, and a third screen frame F by a notch mechanism or the like.
It is preferable that the positions can be fixed at positions corresponding to R3.
In the camera in which the size of the aperture just before the exposed surface of the film is variable and the size of the shooting screen recorded on the film itself can be changed corresponding to the first to third screen frames, the screen frame switching lever 12 and the aperture can be interlocked.

In the above embodiments, the screen frame defining members 7 and 8 are used.
Is the first defining member, the screen frame defining members 9 and 10 are the second defining members, the pinion gear 11 is the driving means, and the cam surface 13,
14, the compression springs 16 and 17 and the cam pins 18 and 19 form an interlocking device and a cam mechanism. 2 shows the first reference positions of the screen frame defining members 7 and 8 and the second reference positions of the screen frame defining members 9 and 10, respectively. The first defining member and the second defining member may be linked by a link mechanism. The present invention can be applied not only to cameras but also to other optical devices.

[0017]

As described above, in the present invention, a part of the screen frame defining member is driven by the driving means, and the other screen frame defining member is moved in association with the operation thereof. It is possible to deal with various types of screen frames while suppressing an increase in the screen frame defining member and its driving means. Therefore, it is possible to provide a simple and small screen frame switching mechanism which is particularly suitable for an optical device such as a camera whose internal space is limited. Especially claims 2 to 5
In the invention described above, the reference screen frame, the screen frame narrowing the screen frame in one direction, and the screen frame narrowing in the other direction can be formed by simply reciprocating the first defining member in the first direction. Can be specified. Further, in the invention of claim 3, it is possible to change the other dimension while fixing one dimension of the screen frame by merely reciprocating the first defining member in the first direction.
The screen frame can be switched while maintaining the symmetry with respect to the optical axis simply by reciprocating the regulating member in the first direction. According to the invention of claim 5, the mode of changing the screen frame is simple by changing the cam shape. Can be changed to

[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.

FIG. 2 is a diagram showing a state in which a first screen frame is defined in the embodiment.

FIG. 3 is a diagram showing a state in which a second screen frame is defined in the embodiment.

FIG. 4 is a diagram showing a state in which a third screen frame is defined in the embodiment.

FIG. 5 is a diagram showing a modification of FIG.

[Explanation of symbols]

 6 Reference frame defining member 7, 8, 9, 10 Screen frame defining member 11 Pinion gear 12 Screen frame switching lever 13, 14 Cam surface 16, 17 Compression spring 18, 19 Cam pin

Claims (6)

[Claims] 1. A screen frame switching mechanism capable of switching screen frames by changing relative positions of a plurality of screen frame defining members in a plane orthogonal to an optical axis of an optical system, wherein the plurality of screen frame defining members are provided. A driving means for driving a part of the screen frame defining member, and an interlocking means for interlocking the operation of the part of the screen frame defining member with another screen frame defining member according to a predetermined condition. Screen frame switching mechanism characterized by. 2. A plurality of screen frame defining members, a first defining member defining a screen frame in a first direction orthogonal to an optical axis of the optical system, and an orthogonal to both the optical axis and the first direction. A second defining member that defines a screen frame with respect to a second direction, the driving means is provided to reciprocally drive the first defining member in the first direction, and the interlocking means includes the first When the defining member is closer to the optical axis than the first reference position, the second defining member is held further than the second reference position with respect to the optical axis, and the first defining member is arranged with respect to the optical axis. The screen frame switching mechanism according to claim 1, wherein the second defining member is closer to the optical axis than the second reference position when the second defining member is located further than the first reference position. 3. When the first defining member is further than the first reference position, the position of the screen frame in the first direction is fixed to a position corresponding to the first reference position, and the second defining member is The screen frame switching mechanism according to claim 2, further comprising a reference frame defining member that fixes a position of the screen frame in the second direction to a position corresponding to the second reference position when the distance is further than the second reference position. . 4. A pair of the first defining member and the second defining member are provided symmetrically with respect to the optical axis, and the driving means reciprocally drives the pair of first defining members in opposite directions to each other in the first direction. 3. The method according to claim 2, wherein
Screen frame switching mechanism described. 5. The screen frame switching mechanism according to claim 2, wherein a cam mechanism using the first defining member as a driving joint and the second defining member as a driven joint is used as the interlocking device. 6. The screen frame switching mechanism according to claim 1, wherein the optical system is a finder optical system provided separately from a photographing optical system of a camera.