JPH09265121A - Finder variable power mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a camera compact by miniaturizing a finder cam and reducing a rotating space. SOLUTION: This camera is provided with zoom lenses 1, 2 and 3 moved to a telephoto end state, a wide-angle end state and a collapsibly mounted state, zoom finders 6 and 7 executing a variable power action by interlocking with the zoom state of the zoom lenses and a finder driving member 4 driving the zoom finders. Then, when the zoom lenses are moved at one part and the whole part between the wide-angle end state and the collapsibly mounted state, the driving of the finders 6 and 7 is stopped by the driving member 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viewfinder variable magnification mechanism most suitable for a camera having a retractable zoom lens.

[0002]

2. Description of the Related Art In a camera having a photographing zoom lens system and a zoom finder system for visually recognizing a photographing range of the photographing zoom lens, a finder zoom operation is performed in conjunction with a zoom operation of the photographing lens. There is.
At this time, the zoom driving force of the photographing lens is directly transmitted to the zoom cam member of the finder to move the finder optical system in the optical axis direction. The shooting operation is not performed while moving from the retracted position to the wide-angle end, so the finder lens must be fixed at the wide-angle end position. For this reason,
As shown in FIG. 10, the finder cam 25 is formed in a flat cam groove 25a so as not to lift the finder lens even when receiving the zoom driving force.

[0003]

In a camera having a retractable zoom lens, since no photographing operation is performed during the movement from the wide-angle end to the collapsible lens, it is necessary for the finder cam to perform the zooming operation. Absent. However, since the zoom driving force is received, the driving force moves in the direction of receiving the driving force. Therefore, as described above, it is necessary to secure the flat groove 25a in the finder cam 25.

Therefore, in a conventional camera having a retractable zoom lens, which has a photographing zoom lens system and a zoom finder system for visually recognizing the photographing range of the photographing zoom lens, a flat cam groove 25a is provided.
However, the formation of the cam causes an increase in the size of the cam, which is an obstacle to the miniaturization of the camera.

The present invention has been made in view of the above problems, and it is an object of the present invention to reduce the size of a finder cam, reduce the rotation space, and promote the size reduction of a camera.

[0006]

In order to achieve this object, a viewfinder zooming mechanism according to the present invention has a zoom lens (1, 1, 2) which moves to a telephoto end state, a wide-angle end state, and a retracted state.
2, 3), a zoom finder (6, 7) that performs a zooming operation in conjunction with the zoom state of the zoom lens, a finder drive member (4) that drives the zoom finder, and the zoom lens is in the wide-angle end state. The finder drive member is configured to stop driving of the zoom finder (6, 7) when moving in a part or all of the retracted state.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of a finder variable magnification mechanism according to the present invention.

In FIG. 1, a helicoid crest 2b is formed on the outer circumference of a taking lens barrel 2 which holds the taking lens 1, and is helicoidally coupled with a fixed helicoid groove (not shown) formed on the inner circumference thereof. There is. Further, an opening 3b is provided on the side surface of the fixed helicoid cylinder 3, and the gear portion 2a formed on the taking lens barrel 2 can be operated from outside the cylinder via the opening 3b.

A pinion 9 is press-fitted into a rotary shaft (not shown) of the motor 8 and transmits a driving force to a stage gear 9a via a gear train (not shown). The output system is divided into two parts from the stepped gear 9a, and one of them is provided with an opening 3 through a gear train (not shown).
The power is transmitted from b to the gear portion 2a looking into the photographing lens barrel 2 to move it back and forth (retract and zoom). The other transmits power to the gear portion 4a via a gear train (not shown). The gear portion 4a is formed on the finder cam drive member 4 which is rotatably fitted to the outer periphery of the fixed helicoid cylinder 3.

The finder cam 5 is a fixed helicoid cylinder 3
It is guided by the positioning boss 3a planted above, slides on the outer periphery of the fixed helicoid cylinder 3, and is driven by the finder cam drive member. Moreover, the floating is prevented by a member (not shown). The finder cam 5 is connected to one end of a finder cam biasing spring 11, and is rattled backward (to the left) by the biasing force of the finder cam biasing spring 11. The other end of the finder cam biasing spring 11 is fixed to the finder cam driving member 4 (see FIG. 2).

FIG. 1 shows a zoom finder in which one of the objective lenses moves in the optical axis direction to perform a zooming operation, and 6 is the moving objective lens. The objective lens 6 is held by a finder lens holding frame 7. The holding frame 7 is guided by the integrally formed guide portion 7a sliding on a guide shaft (not shown), and moves in the optical axis direction. This realizes a zoom finder.

A follower pin 7b is planted in the finder lens holding frame 7, and the follower pin 7b is fitted into the zooming cam groove 5b provided on the finder cam 5, and the finder cam 5 is operated to move the cam groove 5b. Driven along.

2 to 5 are development views of the finder cam 5 and the finder cam driving member 4.

FIG. 2 shows a state in which the taking lens barrel 2 is retracted. At this time, since the finder cam driving member 4 is not in contact with the finder cam 5, no power is transmitted even if it is rotated.

FIG. 3 shows a state (wide-angle state) in which the finder cam drive member 4 has moved from the state of FIG. 2 in the arrow direction (left direction of FIG. 3). At this time, the protrusion 4b first contacts the side surface of the finder cam 5 and transmits power in the arrow direction (left direction in FIG. 3).

FIG. 4 shows the finder cam drive member 4 further leftward from the state shown in FIG. 3 (around the middle). At this time, the finder cam 5 moves in the lower left direction (FIG. 4) by the moving cam groove 5a. Therefore,
Not only the protrusion 4b but also the protrusion 4c comes into contact with the finder cam drive member 4 and can be driven left and right.

FIG. 5 shows a state (a telephoto state) in which the finder cam driving member 4 has moved further leftward from the state shown in FIG.

As can be seen from the movements described with reference to FIGS. 2 to 5, only during the movement from the wide angle to the collapsible state,
The power transmission of the finder cam drive member 4 to the finder cam 5 is cut off. The finder cam 5
It may be a flat plate-shaped slide member.

6 to 8 show vertical cross sections. FIG. 6 shows a collapsed state. The rear lens group constitutes a photographic lens optical system together with the photographic lens 1 (front lens group), and the focal length can be varied by increasing or decreasing the respective intervals.
The taking lens 1 is held by the shutter mechanism 12,
The rear group lens 10 is held by the rear group lens barrel 10a. The rear lens barrel 10a moves back and forth with respect to the taking lens 1 by a cam barrel (not shown). The camera body holds the fixed helicoid cylinder 3 and holds the film 13 on the focus surface. The finder block holds a finder objective lens 16 and a finder eyepiece lens 17, and projects a subject image to a photographer through a finder window 19 and an eyepiece window 20 fixed to a cover 18.

FIG. 7 shows a wide-angle state. The distance between the taking lens 1 and the finder lens 6 does not change when the sunken lens is set. FIG. 8 shows a telephoto state. At this time, the finder lens 6 and the rear lens group 10 perform zooming operations closer to the finder objective lens 16 side and the eyepiece lens 17 side, respectively, as compared with the case of wide angle.

FIG. 9 shows the amount of movement of the cam 5 from the retracted position to the telephoto end during full rest. The solid line is the collapsed state, and the chain double-dashed line is the telephoto end. FIG. 10 shows the amount of movement of the cam 25 of the conventional example. Similarly, the solid line indicates the collapsed state, and the chain double-dashed line indicates the telephoto end. As can be seen from the comparison between FIG. 9 and FIG. 10, it is possible to obviously reduce the space of the finder cam by using the present invention.

[0023]

As described above, according to the viewfinder variable power mechanism of the present invention, the finder drive member moves the zoom finder when moving in a part or all of the wide-angle end state and the retracted state. Since the driving is stopped, unnecessary movement can be reduced and the rotation space of the finder cam can be reduced. for that reason,
There is an advantage that the degree of freedom in designing the peripheral mechanism is expanded, which helps to downsize the camera.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a finder variable power mechanism according to the present invention.

FIG. 2 is a top view showing an embodiment of the finder variable magnification mechanism according to the present invention.

FIG. 3 is a top view showing an embodiment of the finder variable magnification mechanism according to the present invention.

FIG. 4 is a top view showing an embodiment of the finder variable magnification mechanism according to the present invention.

FIG. 5 is a top view showing an embodiment of the finder variable magnification mechanism according to the present invention.

FIG. 6 is a vertical sectional view showing an embodiment of the finder variable magnification mechanism according to the present invention.

FIG. 7 is a vertical sectional view showing an embodiment of a finder variable power mechanism according to the present invention.

FIG. 8 is a vertical cross-sectional view showing an embodiment of the finder variable magnification mechanism according to the present invention.

FIG. 9 is a top view showing an embodiment of the viewfinder variable magnification mechanism according to the present invention.

FIG. 10 is a top view showing an example of a conventional finder variable magnification mechanism.

[Explanation of symbols]

 1 Photographing lens 2 Photographing lens barrel 2a Gear part 2b Helicoid mountain 3 Fixed helicoid cylinder 3a Boss 3b Opening part 4 Finder cam drive member 4a Gear part 4b Projection part 4c Projection part 5 Finder cam 5a Moving cam groove 5b Magnification changing cam Groove 6 Finder lens (objective lens) 7 Finder lens holding frame 7a Guide part 7b Follower pin 8 Motor 9 Pinion 9a Step gear 10 Rear group lens 10a Rear group lens barrel 11 Finder cam biasing spring 12 Shutter mechanism 13 Film 16 Finder Objective lens 17 Finder Eyepiece 18 Cover 19 Finder Window 20 Eyepiece Window 25 Finder Cam 25a Cam Groove

Claims (2)

[Claims] 1. A zoom lens that moves to a telephoto end state, a wide-angle end state, and a retracted state, a zoom finder that performs zooming in conjunction with the zoom state of the zoom lens, and a finder drive that drives the zoom finder. The finder drive member stops driving the zoom finder when the member and the zoom lens move in a part or all of the wide-angle end state and the retracted state. Variable magnification mechanism. 2. The zoom finder according to claim 1, further comprising: a finder cam for performing a zooming operation of the zoom finder, wherein the finder driving member drives the zoom finder by engaging with the finder cam. Even if the finder driving member is driven by releasing the engagement between the finder driving member and the finder cam, the driving of the finder cam is stopped without transmitting the driving force to the finder cam. Characteristic finder variable magnification mechanism.