JPH0366648B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens drive mechanism for an interchangeable lens of a camera, and more specifically, to a camera suitable for advancing and retracting a lens in an interchangeable lens barrel in an automatic focusing camera by a control mechanism from the camera body side. This invention relates to a lens drive mechanism for an interchangeable lens.

In order to automatically adjust the focus of a camera that uses an interchangeable lens, the rotation of a drive control device on the camera side must be transmitted to the lens of the interchangeable lens. If the camera body and lens are integrated, rather than an interchangeable lens, the transmission is easy, but it is also possible to control the SLR camera using an interchangeable lens without impairing other functions of the SLR camera. It is not easy to do. Various structures have already been proposed for moving the lenses of interchangeable lenses forward and backward for the purpose of automatic focusing, but all of them have problems such as being bulky in appearance and having extremely complicated structures. These mechanisms can be roughly divided into two types: a structure in which the lens is driven by the outer periphery of the camera mount, and a structure in which a lever protruding from the lens mount is rotationally driven on the camera body side. The former structure requires gears to be provided around the outer periphery of the lens, which has the problem of significantly impairing the appearance of the lens and making it larger as a whole. The latter structure, which rotates levers etc. within the mount, avoids various coupling mechanisms within the mount for other controls in single-lens reflex cameras, and allows automatic focus adjustment. It is extremely difficult to provide a mechanism for this purpose due to space constraints.

In any of the above-mentioned configurations, the gears for coupling are provided on the rotation center axis, and if you try to couple the gear on the camera body side to the gear provided on the outer periphery of the lens, the small gear will protrude from the front of the camera body. I will have to do it.

The inventor of the present invention has already proposed a lens drive mechanism that uses a connecting pinion supported on the camera body side by a shaft perpendicular to the optical axis. Although this method is a small and reliable mechanism, it has the disadvantage that when it is desired to use an interchangeable lens or camera body equipped with this mechanism in a conventional camera, the gears and the like protrude, making it unusable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lens drive mechanism for an interchangeable lens of a camera capable of automatically focusing, which can transmit the power necessary for driving the lens while maintaining compatibility with a conventional camera mount.

In order to achieve the above object, a lens drive mechanism for an interchangeable lens of a camera according to the present invention transmits the rotational output of a lens drive control device provided in a camera to a lens-side coupling of an interchangeable lens via a body-side coupling. This is a lens drive mechanism for an interchangeable lens of a camera that moves the lens forward and backward, and the shaft of the body-side coupling has a chamfered outer periphery at the coupling end, and is coaxially integrated with the power transmission gear of the lens drive control device. Rotatable and slidable in the optical axis direction of the lens, the coupling end is biased and supported so as to protrude from the surface of the mount of the camera body so as to enter into the opening edge in the lens side flange surface, and the The lens-side coupling ring is parallel to the optical axis of the lens, and its top portion is provided within the opening edge provided in the flange surface of the lens mount so as not to protrude beyond the flange surface, and couples the interchangeable lens to the camera body. When the lens is rotated so that the opening provided in the flange surface of the lens corresponds to the position of the body-side coupling, the body-side coupling enters the opening edge and is coupled or coupled to the lens-side coupling. In this state, the lens-side coupling is rotated by the body-side coupling, which rotates together with the power transmission gear, to drive the lens forward and backward.

According to the above configuration, the object of the present invention can be completely achieved.

The present invention will be described in more detail below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of an interchangeable lens of a lens drive mechanism according to the present invention, and FIG. 2 is a view of the interchangeable lens of FIG. 1 viewed from the lens mount side.
In the figure, 1a indicates a flange surface, and 1b indicates an edge portion of an opening that receives a lens-side coupling provided on this flange surface 1a. FIG. 3 is a front view and a sectional view of the body mount section. The lens-side coupling ring 4 is provided in a part of the lens mount 1, and only the coupling portion 4a of the lens-side coupling ring 4 is exposed.
It is placed slightly rearward from the flange surface 1a to avoid interference with the body mount. The lens-side coupling ring 4 has a rotation axis parallel to the optical axis of the lens, and a spur gear 5 is fixed to the other end by caulking or the like. A large gear 6 meshes with the spur gear 5, and the large gear 6 is provided integrally with the second helicoid 9. A sliding ring 8 is attached to the second helicoid 9, and the sliding ring 8 is supported by the sliding surface 8a of the sliding ring 8 and the sliding surface 6b of the large gear 6 so that it can rotate smoothly on the sliding ring receiver 7. ing. The second helicoid 9 meshes with the first helicoid 10, and the linear fitting 11 is inserted into the first helicoid 10 and is guided so that it can move straight in the optical axis direction. converted into movement. As shown in FIG. 3, the body mount ring 16 is provided with a body side coupling ring 17. The body-side coupling ring 17 has a coupling part 17a that fits loosely into the coupling part 4a of the lens-side coupling ring 4, the circumferential end is a smoothly slid-off escape part 17b, and the tip is connected to the body mount ring. It protrudes slightly from the mounting surface of 16. The other end of the body-side coupling ring 17 can be slid in the optical axis direction of the lens via a spring 18 into a square hole of a power transmission gear 19 that is provided inside the camera body and is connected to a motor (not shown) that is activated by an AF signal. inserted into
It is locked by an E-ring 20.

Next, the operation of the lens drive mechanism of the present invention will be explained mainly with reference to FIG. When attaching the interchangeable lens to the camera body, the lens-side coupling 4 rotates clockwise from the position A in the figure by the lens attachment/detachment angle θ to reach the position B. lens mount 1
When the flange surface 1a of the body mount ring 16 is pressed, the body-side coupling ring 17 is pushed into the body against the biasing force of the spring 18. When the lens-side coupling ring 4 reaches the above-mentioned position B, the coupling portion 4a and the coupling portion 17a are connected to the spring 8.
They fit together due to the biasing force. At this time, the connecting portion 4a
Since the initial position in the rotational direction of the coupling part 17a is not set, the convex part and the recess of the coupling part may not fit together immediately even after the mounting of the mount part is completed. During rotation, the coupling parts 4a and 17a are fitted together by the biasing force of the spring 18. When the attachment of the interchangeable lens is completed, a motor (not shown) is driven by the AF signal and drives the lens side member via the power transmission gear 19.

Next, when removing the interchangeable lens from the camera body, push the interchangeable lens counterclockwise in Fig. 3. There is a slight gap between the coupling part 4a and the coupling part 17a, so the lens can be removed by this gap. Since the rotation relief part 17b is pushed by the edge part 1b of the lens mount 1 and pushed into the camera body, the interchangeable lens can be removed by further rotating the interchangeable lens. In order to retract the body-side coupling ring 17, a release button or the like that engages with the coupling ring may be provided, and after releasing the coupling, the interchangeable lens may be removed by turning it.

As explained in detail above, the mechanism according to the present invention can be reliably coupled with the coupling ring provided on both mounting surfaces of the interchangeable lens and camera body, and can also be used with interchangeable lens camera bodies that do not have conventional automatic focusing mechanisms. , it is possible to provide a lens drive mechanism that is compatible with conventional cameras.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the interchangeable lens of the lens drive mechanism according to the present invention, Fig. 2 is a view of the interchangeable lens of Fig. 1 seen from the lens mount side, and Fig. 3 is a front view of the body mount section. and a cross-sectional view. 1... Lens mount, 1a... Flange surface,
1b...Edge part, 2...Aperture ring, 3...Lens barrel, 4...Lens side coupling, 4a...Joining part, 5...Spur gear, 6...Big gear, 6a...Spur gear part , 6b...Sliding surface, 7...Sliding ring receiver,
7a...Sliding surface, 7b...Sliding surface, 8...Sliding ring, 8a...Sliding surface, 9...Second helicoid, 1
0...First helicoid, 11... Straight fitting, 12
...Front group lens, 13...Rear group lens, 14...
Distance ring, 15... Screw, 16... Body mount ring, 17... Body side coupling, 17a
...joint part, 17b...relief part, 18...spring,
19...Power transmission gear, 20, 21...E ring.

Claims (1)

[Claims] 1 A lens drive mechanism for an interchangeable lens of a camera that transmits the rotational output of a lens drive control device provided in the camera to a lens coupling of an interchangeable lens via a coupling on the body side to move the lens forward or backward, the mechanism for driving the lens on the body side. The coupling end of the shaft of the coupling ring has a chamfered outer periphery, and rotates coaxially with the power transmission gear of the lens drive control device and is slidable in the optical axis direction of the lens, and the coupling end is connected to the lens side flange. The lens-side coupling is parallel to the optical axis of the lens, and its top portion is parallel to the lens mount. The opening edge provided in the flange surface of the lens is provided in such a way that it does not protrude beyond the flange surface, and when the interchangeable lens is rotated to couple to the camera body, the opening provided in the flange surface of the lens is inserted into the body. When the body side coupling is aligned with the position of the side coupling, the body side coupling enters the opening edge and becomes coupled or connectable to the lens side coupling, and the body side coupling rotates together with the power transmission gear. A lens drive mechanism for an interchangeable lens of a camera configured to drive the lens forward and backward by rotating the lens-side coupling ring.