JPH0667262A - Finder optical system switching mechanism of camera - Google Patents

Abstract

(57) [Summary] [Purpose] To downsize the mechanism for switching the magnification by inserting the switching lens at different positions on the optical axis of the finder. A first magnification is obtained by moving a part of the optical system in the optical axis direction and rotating the optical system about an axis perpendicular to the optical axis to half-rotate the part of the optical system on the optical axis. And a second magnification which can be switched between the second magnification and the finder, and a reflection member disposed in the finder optical system for reflecting the finder light, wherein a part of the optical system has an optical power of the first magnification. The first position for forming the system and the second position for forming the optical system of the second magnification are rotatable about the reflection surface of the reflection member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finder optical system switching mechanism for a camera which changes the magnification by moving a part of the optical system.

[0002]

2. Description of the Related Art A device for changing a magnification by moving a part of a finder optical system, especially by moving a part of the optical system in the direction of the finder optical axis and half-turning on the optical axis. A device for changing the magnification of a finder is described in JP-A-63-45543 and is proposed in Japanese Patent Application No. 3-272676.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the one disclosed in Japanese Patent No. 543, one optical system is moved to the finder optical axis in one operation by rotating 180 ° about the optical axis of the finder optical axis. Since it is designed to rotate 180 °,
Since it is necessary to secure the amount of movement in the finder optical axis direction by separating some of the optical systems from the rotation axis, the rotation range of some of the optical systems becomes large, making it difficult to miniaturize the camera. There was a problem that it was easy to become.

Further, in Japanese Patent Application No. 3-272676, a part of the optical system moves from a first position for forming a first magnification to a second position for forming a second magnification. When it is moved to the first position, it moves in parallel within a predetermined range from the first position and moves about the rotation axis between the first position and the second position by 1
Since it rotates 80 ° and again moves in parallel within a predetermined range to reach the second position, the rotation range of the part of the optical system becomes smaller than that of the known one, but the absolute movement in the rotation does not occur. Since the amount is large, it tends to be disadvantageous in reducing the total length of the finder optical system.

The present invention is intended to solve the above problems, and the rotation range of a part of the optical system is small,
Another object of the present invention is to provide a viewfinder optical system switching mechanism for a camera, in which the amount of rotation is reduced and the viewfinder mechanism can be easily miniaturized.

[0006]

In order to achieve the above object, the finder optical system switching mechanism of the camera of the present invention moves a part of the optical system in the direction of the optical axis and at the same time, rotates around an axis perpendicular to the optical axis. In the finder which can be switched between the first magnification and the second magnification by rotating the optical system halfway on the optical axis by rotating the optical system in the finder optical system. And a part of the optical system includes a first position for forming an optical system having a first magnification and an optical system having a second magnification, the reflecting member reflecting the finder light. The second position is rotatable about the reflecting surface of the reflecting member.

[0007]

FIG. 1 is a perspective view showing an embodiment of the present invention.

In FIG. 1, reference numeral 1 is a zoom lens capable of zooming, 2 is a lens barrel for holding the lens, 3 is a quick return mirror, and when not shooting, it enters the shooting optical path and from the subject. Light is guided to the viewfinder above the camera, and a known operation of retracting from the shooting optical path during shooting is performed. Reference numerals 4 and 5 are condenser lenses, and 6 is a reflection mirror, which bends the subject light directed upwards to the rear. 7 is a magnification switching lens of positive refractive power, 8 is a lens holder, 9 is a switching lever,
A switching gear 10 is rotatably supported by a shaft. Reference numeral 11 is a switching connecting plate, 12 is a toggle spring, and 13 and 14 are reflection mirrors, and the reflection mirror 13 bends the subject light traveling backward to the left, and the reflection mirror 14 bends the subject light backward again. 15 is a convex lens,
Reference numeral 16 is an eyepiece lens. Then, the condenser lenses 4 and 5, the switching lens 7, the convex lens 15, and the eyepiece lens 1
6 constitutes a finder optical system.

FIG. 1 shows a normal viewfinder state. When the switching lens is rotated 90 ° counterclockwise from this state, a telescopic optical system having a magnification higher than that of the normal viewfinder state is obtained.

FIG. 2 shows the finder in the standard state, and FIG.
Indicates a telephoto state.

In FIGS. 2 and 3, reference numeral 17 denotes a finder base plate to which the reflecting mirror 6, the reflecting mirror 13, the reflecting mirror 14, the convex lens 15 and the eyepiece lens 16 are fixed. Further, the condenser lenses 4 and 5 are coupled to a main body (not shown).

On the other hand, the lens holder 8 holds the switching lens 7 and is fixed to the switching lever 9. The switching lever 9 has a hole formed by removing the center line, and is rotatably fitted to a shaft 17c planted in the finder base plate 17, and the switching gear 10 has a hole in the switching lever 9 and the finder optical axis. Is fixed to the switching lever 9 so as to be concentric in the vertical direction. Although a hole may be provided on the center line of the switching lever, in that case, the distance between the optical axis incident on the reflection mirror 13 and the optical axis after reflection by the mirror 14 is slightly widened.

The switching connecting plate 11 is rotatably fitted to the finder base plate 17 and held by screws 18, and meshes with the switching gear 10. Further, the switching connecting plate 11 has an operating portion 11a and is engaged with an operating knob that is operated from the outside of a caging (not shown). By manually operating the operating knob, the switching connecting plate 11 is opened by the finder light. Rotate around an axis perpendicular to the axis.

The toggle spring 12 has a switching gear 1 at the end 12a.
No. 0 shaft 10a is engaged, and the other end 12b is engaged with the shaft 11b of the switching connecting plate 11.

The reflecting mirror 13 is fixed so as to have a reflecting surface on the rotation axis of the switching lever 9.

Next, the operation will be described.

FIG. 2 shows a normal viewfinder state. The toggle spring 12 has an end 12a engaged with the pin 10a of the switching gear 10, and the other end 12b of the toggle spring 12 has a pin 11 of the switching connecting plate 11.
Although it is engaged with b and urges the switching gear 10 to rotate clockwise, the protrusion 8 of the lens holder 8
Since a is in contact with the stopper portion 17a of the finder base plate 17 to prevent the rotation, the optical axis 1 of the switching lens 7 is held at a position matching the finder optical axis L.

When the operating knob (not shown) is operated in this finder state to rotate the switching connecting plate 11 in the clockwise direction, the switching gear 10 is rotated in the counterclockwise direction by meshing with the switching connecting plate. .

As the switching connecting plate 11 rotates, the distance between the shaft 10a of the switching connecting gear 10 and the shaft 11b of the switching connecting plate 11 becomes shorter, and when the rotation of the switching connecting gear 10 is about half, the distance becomes shorter. Is the shortest. At this time, the biasing force of the toggle spring becomes maximum. At this boundary, the rotation direction of the switching gear 10 is switched by the urging force of the toggle spring 12.

When the switching connecting plate 11 is further rotated, the toggle spring 12 exerts an urging force to rotate the switching gear 10 in the counterclockwise direction. As a result, the switching gear 10 causes the projection 8b of the lens holder 8 to move. The switching lens 7 is rotated until it comes into contact with the stopper portion 17b of the finder base plate.
Is held at a position where the optical axis l of the finder coincides with the finder optical axis L. As a result, the switching lens is the same as moving the finder optical axis L by a predetermined amount.

FIG. 3 shows this final state. In this state, the telephoto optical system is obtained by rotating the switching lens 90 ° from the above-mentioned viewfinder state.

When switching from the telephoto optical system to the reference finder optical system, the above operation is reversed.

Although the finder telescope switching mechanism in the TTL finder has been shown in the above-mentioned embodiment, the mechanism can be applied to an external finder. Further, in the above-described embodiment, the switching mechanism in which the switching lens 7 is rotated by 90 ° is shown, but the rotational angle of the switching lens 7 is made smaller than 90 ° by changing the angles of the reflection mirrors 13 and 14. Is also possible.

[0024]

As described above, according to the present invention,
A part of the optical system, which is moved to change the magnification of the finder, rotates about the reflection surface of the reflection member that reflects the finder light, so that the first magnification and the first magnification can be adjusted before and after the reflection of the finder light. An optical system having a magnification of 2 can be configured, the rotation range of the part of the optical system is small, and
The amount of rotation is small, and the finder mechanism can be downsized.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a plan view of a standard state of a viewfinder of the camera shown in FIG.

FIG. 3 is a plan view of the finder in a telephoto state.

[Explanation of symbols]

 1 Photographic lens 2 Lens barrel 3 Quick return mirror 4,5 Condenser lens 6,13,14 Reflecting mirror 7 Switching lens 8 Lens holder 9 Switching lever 10 Switching gear 11 Switching connection plate 12 Toggle spring 15 Convex lens 16 Eyepiece lens 17 Finder ground plate

Claims (1)

[Claims] 1. A part of the optical system is moved in the direction of the optical axis and is rotated about an axis perpendicular to the optical axis to partially rotate the part of the optical system halfway on the optical axis. In the finder which can be switched between the second magnification and the second magnification, a finder optical system is provided with a reflecting member for reflecting the finder light, and a part of the optical system has the first magnification. The first position for constructing the optical system and the second position for constructing the optical system of the second magnification are rotatable on the reflecting surface of the reflecting member. Characteristic camera viewfinder optical system switching mechanism.