JPS581B2 - Tenchiyousetsouchi - Google Patents

Description

[Detailed description of the invention] The present invention relates to a focus adjustment device for a camera or the like.

In general, autofocus cameras adjust the focus of the photographic lens according to the distance measurement results of a distance measurement device inside the camera body. This requires a special lens with an interlocking mechanism.

Therefore, simple focus adjustment such as automatic focus adjustment cannot be performed using a camera body that does not have the above-mentioned device or a lens that does not have the above-mentioned interlocking mechanism.

As a means to solve this problem, the applicant of the present application has filed Japanese Patent Application No. 17161/1983 (Japanese Patent Application Laid-open No. 113228/1983).
In this embodiment, a focus detection device and a focus detection device such as a helicoid mechanism driven according to the output of the focus detection device are attached to an adapter such as a rear converter installed between the camera body and the photographic lens. A configuration is disclosed in which an adjustment device is provided and automatic focus adjustment is possible by using the adapter even if the photographic lens and camera body are not dedicated as described above.

However, in such a device, since the weight of the photographic lens is placed on the adapter, a large operating force is required to drive the helicoid mechanism, which has the drawback of increasing the size of the device.

The present invention has been made in view of the above points,
The purpose is to provide a focus adjustment device that allows simple focus adjustment such as automatic focus adjustment without using a dedicated main body or lens as described above, and does not require a large operating force for focus adjustment. There is a particular thing.

The present invention will be explained below with reference to Examples.

1 and 2 respectively show different embodiments of the present invention, the solid line portion is the portion according to the present invention, and the chain line portion is the portion of a normal camera to which the device of the present invention is attached.

1 is a lens barrel, 2 is a photographic lens built into 1, and the figure shows the case of a standard lens.

3 is the camera body. In the embodiment shown in FIG. 1, A is a variable optical power lens system, and B is a focus detection device.

A and B are connected by a cord 18, and in use, the focus detection device B is attached to the camera body 3 in the same way as when changing lenses, and the photographing lens barrel 1 is attached to this B.
(Interchangeable lenses such as telephoto lenses may be used here)
is attached, and a variable power lens system A is attached to the front of the lens barrel 1.

Part A is a liquid lens, 4 and 5 are glass plates, and 6°7 is a transparent elastic membrane, dividing the space between 4 and 5 into three parts, with a low refractive index liquid (fallen tree) 8 in the center, and a liquid on both sides. is filled with a liquid 9 having a high refractive index (for example, cedar oil), and the two spaces filled with 9 are communicated by a pipe 10.

14 is a cylinder into which a piston 13 is fitted; the left side of the piston 13 is filled with liquid 9 and communicates with the space between the glass plate 4 and the membrane 6 through a pipe 11; It is filled with a liquid 8 and communicated with the space between the membranes 6 and 7 by a pipe 12.

The membranes 6 and 7 bulge outward, and the section A as a whole forms a diverging system, and by moving the piston 13, the amount of bulge of the membranes 6 and 7 is changed to adjust the refractive power, that is, the optical power.

The piston 13 is moved by the rotation of the screw 17,
The screw 17 is rotated by a servo motor 16.

15 is a housing 19 forming the entire A district.

In the B part, a semi-transparent mirror 20 is installed in the housing 19, and a part of the photographing light passes through the auxiliary distance measuring lens 21 and reaches the light receiving element 2.
Sent to 2.

Reference numeral 23 is a control unit which processes the output signal of the light receiving element 22 to detect focus and controls the drive of the servo motor 16 which adjusts the power of the variable power lens system, and also has a built-in power supply.

A control signal issued from the control section 23 is sent to the servo motor 16 by a code 18.

Part B is inserted between the camera body 3 and the photographic lens 2, and the distance from the lens 2 to the film surface becomes longer.
This difference in distance is compensated for by using the lens system in section A as a diverging system.

When the servo motor 16 is rotated by the output signal from the control device 23 and the bulge of the membrane 6.7 is adjusted, the power of the section A changes, thereby the focal position of the photographic lens 2 moves, and at the in-focus position, the control device The output signal from 23 becomes 0,
Motor 16 stops.

In FIG. 2, the camera body 3 has a focus detection device 31,
This is an embodiment of the present invention that is effective when the photographic lens barrel 1 does not have an interlocking mechanism with the focus detection device 31.

Part A, which can be attached and detached in front of the photographic lens, has a variable power lens system that includes a concave lens 34 and a convex lens 35, and can change the overall power by changing the distance between both lenses.

Reference numeral 32 denotes a control device connectable to the focus detection device 31 in the camera body, and the device 32 drives a servo motor that adjusts the power of the variable power lens system according to the output of the focus detection device 31. It has a built-in instruction device for controlling and the servo motor, and is detachable from the camera body 3.

The rotation of the servo motor within the control device 32 is transmitted to section A via the flexible shaft 33.

In part A, 37 is a mounting barrel, in which the pinion 40 is supported by bearings 41 and 42 provided in the main body 37,
40 is connected to the flexible shaft 33.

The inner cylinder 36 is fitted into the main body 37 via a helicoid screw 38, and the pinion 40 meshes with a gear 39 formed on the inner surface of the outward folded part of the inner cylinder 36. As the inner cylinder 36 rotates, it moves back and forth, and since the concave lens 34 is held in the inner cylinder 36, the power of the section A changes as the inner cylinder 36 moves back and forth.

The lens 34 moves back and forth until it focuses on the film surface.
It stops when it reaches the in-focus position.

The feature of the embodiments shown in Figs. 1 and 2 is that a variable power lens system is added in front of the existing lens, and the power is changed by the output of the focus detection control section to adjust the focus. be.

Manual focusing of a normal photographic lens is performed by moving all or part of the lens inside the lens barrel back and forth, and in order to enable automatic focusing of a camera, the lens must be moved in the same way as manual focusing. If this were to be done, the additional equipment would be very complex and large, and it would be extremely difficult to fit it into an appropriate form as an adapter to be added to a normal camera.

On the other hand, in the above embodiment, the power of the variable power lens system installed in front of the photographic lens is changed, and there is no need to move the existing lens (which is manually operated), so it is mechanically simple and the form is simple. It is also possible to make it into an appropriate shape as an adapter to be attached to a normal camera.

Furthermore, this variable power lens system can be used not only for automatic focus adjustment, but also as a close-up lens.

In the above embodiment, the power variable additional lens system (the first,
Although the power change shown in part A in Figure 2 is automatically performed, the present invention is not limited to this. For example, the focus direction is displayed and the focus/focus is changed depending on the distance measurement result of the focus detection device. An out-of-focus display is displayed and the power can be adjusted manually by looking at the display, or the adjustment direction can be controlled so that the power can be adjusted only in the in-focus direction, and the power adjustment is locked in the in-focus state. The adapter may be configured to manually adjust the power so that the
It is sufficient that adjustment information generating means for generating adjustment information for power adjustment according to the distance measurement result is provided.

Further, the power adjustment of the additional lens system is not limited to continuous adjustment, and a configuration based on the concept of zone focusing is also possible.

In this case, a switching method such as a turret type, a cam type, or in the case of a liquid lens, filling or draining the liquid can be used.

Further, the distance measuring device is not limited to a focus detecting device that detects whether the lens is in focus or out of focus using the TTL method as in the illustrated embodiment, but may include a distance detecting device that detects the distance to the subject. You may also do so.

As described above, the focus adjustment device of the present invention includes a variable power auxiliary optical system that can be attached and detached in front of the optical system used, a power adjustment means that can adjust the power of the variable power auxiliary optical system, and a focusing device. Depending on the distance measurement results of the detection device and distance detection device,
an optical system comprising adjustment information generating means for controlling the drive of the power adjusting means, instructing the focusing direction and instructing the focusing state, and in which the power adjusting means and the adjusting information generating means are also used. Alternatively, it can be detachably attached to the main body, and is characterized by being in the form of an adapter as a whole.By configuring it in this way, it is possible to have an interlocking mechanism between the camera main body, which does not have a distance measuring device, and the distance measuring device. When using a camera with a rangefinder and a lens that does not have the above-mentioned interlocking mechanism, or a telescope that does not have an automatic focus adjustment device, adjust the focus while watching the display on the adapter. Focus adjustment can be performed until the power adjustment of the variable power auxiliary optical system is locked, or automatic focus adjustment can be performed, so the focus adjustment operation can be simplified.

Furthermore, the power adjusting means in the present invention only needs to adjust the power of the variable power auxiliary optical system installed in front of the optical system used, and the weight of the lens or main body is not applied to the variable power auxiliary optical system. The power of the auxiliary optical system can be adjusted with a small operating force, and even when performing automatic focus adjustment, the power can be changed at high speed with small power consumption.

Furthermore, when used in a camera, focus adjustment can be easily performed even if a lens without a focus adjustment mechanism, such as a bellows lens, is used.

[Brief explanation of the drawing]

1 and 2 are longitudinal sectional side views of different embodiments of the present invention, respectively. 1.2... Optical system, 3... Optical device main body, A... Variable optical power auxiliary optical system, B.
... Focus detection control device, 16 ... Power adjustment means, 22 ... Light receiving element for distance measurement, 23 ...
... Adjustment information generating means, 32 ... Adjustment information generating means and power adjusting means, 33 ... Flexible shaft.

Claims (1)

[Claims] 1 An optical device that can be detachably attached to an optical system such as a photographic lens that is used integrally with the main body of an optical device such as a camera body, and that changes the position of the combined focal point with the optical system by changing its own optical power. a variable power auxiliary optical system; a power adjustment means that is detachable from the optical system or the optical device body; and a power adjusting means for adjusting the optical power of the variable optical power auxiliary optical system; What is claimed is: 1. A focus adjustment device that is flexible and has an adjustment information generating means that generates information for adjusting the power adjustment means in accordance with a distance measurement result, and that the focus adjustment device is in the form of an adapter as a whole.