JPH0336991Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a movable mirror adjustment device that adjusts the viewfinder focus imaging position (upper focus adjustment) of a single-lens reflex camera by adjusting a movable mirror.

Conventionally, the above pins could be adjusted by positioning the focusing plate mounting surface using three adjustment screws, and rotating the above screws with a screwdriver from the lens mount opening.
It has been common practice to insert an adjustment seat plate between the focus plate and the focus plate mounting surface to perform positioning. However, all of these conventional means have an unavoidable drawback in that they cannot be adjusted while observing the viewfinder image. Another problem is that parallax is likely to occur between the photographed image and the viewfinder image due to misalignment between the reflective surface of the mirror and the pivot point, or misalignment of the pivot point with respect to the camera reference plane (for example, the film surface). This latter problem is caused by variations in the dimensional accuracy of the components, and occurs because the designed reflection point on the optical axis of the movable mirror does not match the actual reflection point.

Actual Publication No. 49-35319 and Special Publication No. 56-5973 are
This problem has been solved. However, this technology basically allows the position of the rotation fulcrum of the movable mirror to be adjusted with respect to the reference plane of the mirror box (for example, the film surface) so that the reflection point coincides with the designed reflection point. Therefore, the above problem cannot be solved with a device in which the rotation fulcrum is fixed to the mirror box.

In view of the problems of the prior art, the present invention provides an adjustment device that can adjust the upper pin using a movable mirror, regardless of whether the rotation fulcrum of the movable mirror is fixed or adjustable. The pivot point of the movable mirror is provided at the upper end of a support arm made of a separate member from the support frame of the mirror, and the angle of the movable mirror support frame can be adjusted with respect to this support arm. It is characterized by being attached to.

The invention will now be described with reference to the illustrated embodiments. 1 and 2 show a first embodiment of the present invention. 11 is a mirror box, 12 is a movable mirror, and 13 is a movable mirror support frame in which the movable mirror 12 is supported by three convex portions 14 (only one is shown in FIG. 1). A feature of the present invention is that the pivot point of the movable mirror support frame 13 is not formed in the support frame 13 itself, and the mirror box 11
A support arm 16, which serves as a rotational fulcrum for the movable mirror, is pivotally attached to both sides (only one is shown) of the movable mirror around a shaft 15. The support arm 16 and the movable mirror support frame 13 are pivotally connected to each other by a rotation shaft 17, and are normally urged by a spring 18 so as to come into elastic contact with each other. The spring 18 has a central coil portion wound around the rotating shaft 17, and leg portions at both ends hooked onto the support arm 16 and the back surface of the movable mirror support frame 13. A screw base 19 is fixed to the support arm 16, and an adjustment screw 2 screwed therein is fixed to the support arm 16.
0 is in contact with the back surface of the movable mirror support frame 13 against the biasing force of the spring 18. Therefore, when the screwing position of the adjustment screw 20 is changed, the movable mirror support frame 13, that is, the movable mirror 12, rotates about the rotation axis 17 and changes the angle with respect to the support arm 16. In FIG. 1, reference numeral 21 indicates a focus plate, and 22 indicates a film. Reference numeral 23 denotes a conventionally known regulating pin, which is moved up and down by a mirror angle adjusting means (not shown) to regulate the 45° position of the movable mirror 12.

According to this device having the above configuration, by rotating the adjustment screw 20, the support arm 1 of the movable mirror 12 is adjusted.
The angle with respect to 6 can be adjusted, and the 45° position can be adjusted with the regulating pin 23. In other words, the direction of the reflective surface of the movable mirror 12 can be changed with respect to the axis 15, and by cooperating with adjustment by the regulating pin 23, the mirror reflective point P on the optical axis can be aligned with the designed position. Therefore, the upper focus can be adjusted without moving the focus plate 21. Furthermore, since this adjustment can be performed through the rear opening of the mirror box 11, it can be performed while the lens is still attached while observing through the viewfinder.

The above adjustment can be explained theoretically as follows. In a single-lens reflex camera, the position of the movable mirror is determined by the following equation: a, where P is the reflection point on the optical axis of the photographing lens, a is the distance from point P to the focal point of the reticle, and b is the distance to the image plane of the film. = b (disclosed in Japanese Patent Publication No. 56-5975). Conventionally, by adjusting the tilt angle of the movable mirror (generally 45°),
As mentioned above, the position of the reflection point P shifts in the front-back direction,
Distance b changes. For this reason, a was corrected by adjusting the position of the focus plate so that a=b. This means that the position of the reflection point P deviates from the designed position, which causes parallax between the viewfinder image and the photographed image. According to the present invention, by rotating the adjusting screw 20 as described above, the shaft 1
Since the angle of movable mirror 12 with respect to 5 changes,
Coupled with the adjustment of the regulating pin 23, a=b can be achieved without causing the above-mentioned parallax.

FIG. 3 shows another embodiment of the invention. In this embodiment, the support arms 16 on both sides are made of an elastic material, the lower ends of which are fixed to the movable mirror support frame 13 with pins 24, and the movable mirror support frame 13 is biased in the direction in which the movable mirror support frame 13 comes into elastic contact with the support arms 16. There is.
The screw head 19 and the adjustment screw 20 are the same components as in the first embodiment, and the adjustment screw 20 is moved against the biasing force of the support arm 16 to the movable mirror support frame 1.
The angle of 3 is regulated. This embodiment also provides the same effects as the first embodiment.

As described above, according to the present invention, the reflection point of the movable mirror can be aligned with the designed position regardless of whether the rotation fulcrum of the movable mirror is fixed to the mirror box, and the focusing point can be aligned with the designed position. Neither vertical position adjustment means nor viewfinder parallax adjustment means are required. Furthermore, according to the present invention, adjustment operations can be performed from the back of the mirror box while observing the viewfinder image, so adjustment operations can be performed easily, quickly, and reliably.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the first embodiment of the present invention;
FIG. 2 is a perspective view of the main parts, and FIG. 3 is a perspective view of the main parts showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 11... Mirror box, 12... Movable mirror, 13... Movable mirror support frame, 15... Axis (rotation fulcrum of movable mirror), 16... Support arm, 1
7...Rotation axis, 20...Adjustment screw.

Claims (1)

[Claims for Utility Model Registration] (1) A movable mirror support frame; a support arm whose one end supports the movable mirror support frame and whose other end is pivotally attached to the mirror box; an elastic means for biasing the mirror support frame to rotate around the support part in a direction toward the support arm; and an elastic means screwed onto the support arm from the back side of the movable mirror so that the distal end comes into elastic contact with the movable mirror support frame; A movable mirror for a single-lens reflex camera, comprising: a screw, and the angle between the movable mirror support frame and the support arm can be adjusted against the rotation biasing force by rotating the adjustment screw. Adjustment device. (2) In claim 1 of the utility model registration claim, one end of the support arm is provided with a rotation shaft to which a movable mirror support frame is pivoted, and the movable mirror support frame is rotated about this rotation axis. A movable mirror adjustment device for a single-lens reflex camera that is rotationally biased. (3) In claim 1 of the utility model registration claim, the support arm is made of an elastic member, one end of the support arm is in elastic contact with the movable mirror support frame, and the movable mirror support frame is brought into elastic contact with the support arm. A movable mirror adjustment device for fixed single-lens reflex cameras.