JP2607715B2 - camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera, particularly a single-lens reflex camera, having a movable mirror that swings from a finder observation position to a shooting retract position.

[Prior Art] FIGS. 6 to 8 are central sectional views of the vicinity of a movable mirror of a single-lens reflex camera, and are views for explaining an optimum position of a swing fulcrum of a movable mirror 26. FIG. In the figure, 110 is the last lens of the taking lens system, 101 is a lens barrel holding the lens 110, 100 is a mirror box holding the mirror 26, the focus plate 102, and the pentaprism 103, and 105 is a focal plane shutter Reference numeral 104 denotes an aperture of the camera body.

In a single-lens reflex camera, it is important that the mirror is as far away from the aperture of the camera body as possible when the mirror is raised to the shooting retract position. This is because the reflected light on the back surface of a mirror holding member (not shown) that holds the mirror causes flare or ghost, or in extreme cases, the photographing light flux is vignetted by the mirror holding member. FIG. 6 is a diagram showing such an unfavorable situation.
This is an example provided at the position indicated by 7. In this case, the distance between the raised mirror 26a and the optical axis 106 of the photographing lens is short, and a ghost occurs on the photographing surface due to the back surface of the mirror holding member (not shown). In consideration of this point, FIG. 7 shows an example in which a swing fulcrum is provided at a position indicated by reference numeral 108 so that the mirror is raised sufficiently away from the optical axis 106. However, in this case, the trajectory of the mirror tip interferes with the lens barrel 101, causing a problem. FIG. 8 shows an example in which this point is further taken into consideration, and the swing fulcrum is provided at the position indicated by reference numeral 109 so that the mirror ascending position is sufficiently away from the optical axis and the trajectory of the mirror does not interfere with the lens barrel 101 of the taking lens. is there. As a result, a good photographed image without flare, ghost, etc. can be obtained. As described above, from FIGS. 6 to 8, the fulcrum of the mirror is set to the focal plane shutter.
It is clear that moving the mirror closer to 105 moves the mirror raising position in the preferred direction.

[Problem to be Solved by the Invention] However, in order to actually bring the swing fulcrum closer to the focal plane shutter, a through hole serving as a swing fulcrum is formed on the side surface of the mirror box 100, but this is a main mirror. If the holding member is made of plastic and the hinge shaft is also integrally formed, the hinge shaft becomes large, the clearance with the shutter is lost, the formation of the through hole becomes difficult, and the swing fulcrum is moved to the position shown in FIG. Then, the tip of the mirror is cut to guarantee the swinging of the mirror while allowing a so-called inconvenience such as breakage of the mirror, or the swing fulcrum is set at the position shown in FIG. 6 to allow the ghost or the like. Was either.

FIG. 9 is an explanatory view of mirror breakage development, and shows a state where the mirror tip is cut so that the mirror can swing at the swing fulcrum position shown in FIG.

In the figure, reference numeral 227 denotes a light beam that reaches the lower part of the screen when a photographing lens having a relatively long exit pupil position from the image plane is attached. Since the tip of the mirror 226 is short, only the light beam 228 is observed in the finder system out of this light beam, resulting in an extremely dark image. As a result, the viewfinder image has a state in which the upper portion of the field of view is missing, and a problem occurs in that the subject cannot be observed.

Japanese Utility Model Laid-Open No. 59-63353 discloses a technique in which a shutter base plate is cut out, and a swing fulcrum of a mirror is made to enter the shutter base plate. Or have to
There is a problem that the space for the shutter drive mechanism is restricted.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem, and to arrange a pivot point of a mirror at an ideal position without increasing the size of a shutter or the like, without causing a mirror break or giving an image to a captured image. It is to provide a camera.

[Means for Solving the Problems] The gist for achieving the object of the present invention is as follows.
A mirror box is provided at the front of the focal plane shutter of the camera body, and a mirror that is rotatable between the finder observation position and the shooting retract position is attached to the mirror box. A support shaft is provided, and the support shaft is rotatably supported on the rear end surfaces of both side walls of the mirror box to form a U-shaped groove serving as a swing fulcrum of the mirror, and the U-shaped groove is supported by the U-shaped groove. Set the support shaft to the U
The camera is characterized in that a holding member for pressing the inside of the groove is provided on the rear end surfaces of both side walls of the mirror box.

[Operation] In the camera having the above-described configuration, a support shaft serving as a rotation fulcrum of the mirror is provided at one end, and the support shaft is formed with a simple structure by a U-shaped groove formed on the rear end surface of the mirror box and a holding member. The bearing can be supported without any backlash.

Therefore, the position of the tip of the mirror can be extended, and the position at which the mirror is raised can be sufficiently separated from the optical axis of the taking lens, thereby preventing the mirror from breaking for a taking lens having a long focal length and holding the mirror. By preventing flare and ghost light generated by the mirror holding member from entering the imaging surface, a good captured image can be obtained.

[Embodiment] FIGS. 1 to 5 show an embodiment of a camera according to the present invention.

FIG. 1 is a side view of the rotating mirror in a mirror down state.

Reference numeral 16 denotes a main mirror holding member for holding a main mirror 26, which is a half mirror, formed of, for example, plastic. Support shafts 16b and 16b 'are integrally formed on one side end.

As shown in FIGS. 2 to 5, the main mirror holding member 16 is housed in a mirror box 120 integrally formed of plastic, and has a U-shaped groove 120b recessed in the rear end surfaces of both side walls of the mirror box 120. , 120d are fitted with the support shafts 16b, 16b ', rotatably supported by the support shafts 16b, 16b', and the main mirror holding member 16 is brought into contact with a stopper 31 protruding from the inner surface of the side wall. By contact, the counterclockwise rotation of the main mirror holding member 16 is regulated, and the main mirror holding member 16 is held at the mirror down position.

The driving of the mirror holding member between the mirror down position (viewer observation position) and the mirror up position (exposure position) is performed by the spring force of the mirror up spring 14 as shown in FIG. The operation is performed in cooperation with the cam 8 and the levers 11 and 12 which are rotated by the motor 1, which will be described later. These driving forces are performed via driving pins 16a provided on the mirror holding member 16.

Reference numeral 27 denotes a sub-mirror for distance measurement, which is fixed to a sub-mirror holding member 25 and is provided with a shaft 16 provided integrally with the mirror holding member 16.
It is swingably supported by c. Spring 29 is spring hook 1
6d, one end 29a of the arm portion abuts on the mirror holding member 16, the other end 29b abuts on the action portion 25a of the sub mirror holding member 25, and the sub mirror holding member is in the mirror down position.
A toggle reversing mechanism for biasing the sub-mirror holding member 25 in the clockwise direction at the mirror-up position is formed by biasing the spring 25 in the counterclockwise direction. However, in order to operate the toggle inversion operation, an additional cam member is required, which will be described later with reference to FIGS.

Numeral 30 denotes an optical axis, which indicates an optical axis of a central light beam entering the camera body through a not-shown photographing lens. The optical axis 30a is an optical axis through the taking lens,
0b is reflected on the surface of the half mirror 26 and guided to a finder optical system (not shown). The optical axis 30c is an optical axis that passes through the half mirror 26, is totally reflected by the sub mirror 27, and is guided to the distance measuring unit 28. Various proposals have been made for the configuration of the distance measuring unit 28, which are well-known and will not be described in detail.

2 to 5 are views showing only a main part in a state where the mirror mechanism shown in FIG. 1 is incorporated in the mirror box 120, and FIGS. 2 and 3 are respectively viewed from the left and right. FIG. 4 is a side view showing the operating state, and FIG. 5 is an enlarged view of a movable fulcrum of the main mirror. In the figure, reference numeral 121 denotes an eccentricity-adjustable pin provided on the side surface of the mirror box 120, which determines the open position of the main mirror 26 in the viewfinder observation state by coming into contact with the first arm 25a of the sub-mirror holding member 25. The second arm portion 25b of the sub-mirror holding member 25
Are in contact with each other to form the aforementioned toggle inversion mechanism.

Here, reference numeral 121a denotes a flange, and the eccentric pin 121 is rotatably supported on the inner wall of the mirror box around the center of a caulking foot (not shown) so as not to fluctuate. 121b is a hexagonal hole, and this hole 121b is formed so as to penetrate concentrically with the rotation center. Reference numeral 121c denotes the center of the eccentric pin 121, which is set at a position eccentric with respect to the rotation center as understood in the drawing, and by inserting an adjustment tool into the hexagonal hole 121b and rotating it, a viewfinder observation state is obtained. Can be adjusted.

Reference numerals 122 and 123 denote holding plates made of a thin metal plate for pivotally supporting the shafts 16b and 16b 'of the main mirror holding member 16 on the walls on both sides of the box-shaped mirror box 120. It is attached to the rear end face of both side walls of. On both side walls of the mirror box 120, U-shaped grooves 120d and 120b are formed as shown in FIG. 5, so that the shafts 16b and 16b 'of the main mirror holding member are respectively dropped and rotatably fitted. It is configured. The pressing plates 122 and 123 are disposed so as to close the opening of the U-shaped groove, and a spring force acts on the shafts 16b and 16b 'to prevent the shafts 16b and 16b' from swinging when the mirror is raised. It is configured as follows. At this time, the holding plate 122,123
Is a thin plate made of metal or the like, the shafts 16b and 16b 'can be arranged at the end of the mirror box 120 near the focal plane shutter, and an optimum swing fulcrum can be obtained.

[Effects of the Invention] According to the present invention, a support shaft serving as a rotation support point of a mirror is provided at one end, and this support shaft has a simple structure by a U-shaped groove and a holding member formed on the rear end surface of the mirror box. The bearing can be supported without play by the formed bearing.

Therefore, the position of the tip of the mirror can be extended, and the position at which the mirror is raised can be sufficiently separated from the optical axis of the taking lens, thereby preventing the mirror from breaking for a taking lens having a long focal length and holding the mirror. By preventing flare and ghost light generated by the mirror holding member from entering the imaging surface, a good captured image can be obtained.

Further, since the mirror mechanism does not enter the shutter mechanism side, the conventional shutter mechanism can be used without being changed.

Further, even if the main mirror hinge shaft is integrally formed of plastic with the receiving plate, the main mirror can be held even if the hinge shaft is eliminated.

[Brief description of the drawings]

1 to 5 show an embodiment of a camera according to the present invention. FIG. 1 is a side view of a mirror, and FIGS. 2 and 3 are left and right side views showing a state where the mirror is mounted in a mirror box. FIGS. 4 and 5 are side views showing the state in which the mirror is raised, FIG. 5 is an enlarged view of the pivot point of the mirror box, and FIGS. 6 to 8 are the positions of the pivot point and the raised position of the mirror, respectively. FIG. 9 is a diagram for explaining a mirror breakage. 16: Main mirror holding member 16b, 16b ': Support shaft 25: Sub mirror holding member 27: Sub mirror, 29: Spring 120: Mirror box, 120d, 120b: U-shaped groove

Claims (1)

(57) [Claims] 1. A camera in which a mirror box is provided in front of a focal plane shutter of a camera body, and a mirror which is rotatable between a finder observation position and a shooting retract position is attached to the mirror box. A support shaft is provided on both sides of one end of the mirror box, and the support shaft is rotatably supported on the rear end surfaces of both side walls of the mirror box to form a U-shaped groove serving as a swing fulcrum of the mirror.
A camera, wherein a holding member for pressing the support shaft supported by the U-shaped groove into the U-shaped groove is provided on rear end surfaces of both side walls of the mirror box.