JPH0370211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an automatic focusing camera, more specifically, a focus detection device, a focus drive motor, etc. are arranged on the camera body side, and are detachably attached to the camera body. The present invention relates to an autofocus camera in which various interchangeable lenses are moved and focused by the drive of a motor on the camera body side.

Various types of autofocus cameras of this type have already been proposed. For example, JP-A-55-
In the autofocus camera of No. 95933, a drive transmission gear group is installed on the outside of the lens barrel, which is configured to move and focus the lens barrel by a motor installed on the camera body side. Because of this arrangement, the lower part of the lens barrel becomes large, which poses holding problems.Also, since a bevel gear is used in the drive transmission gear group, a drop in drive transmission efficiency is unavoidable. It is becoming.

Furthermore, in the autofocus camera disclosed in JP-A No. 55-115024, the drive shaft of the drive motor disposed on the camera body side is disposed at right angles to the direction of movement of the barrel lens, so Although it is a focusing lens and has no problem with objects with small moving force,
For medium- to long-focal-length barrel lenses that require a large amount of movement, a drive motor is also provided on the barrel lens side, and the rotation of this motor is controlled, so that the focusing on the camera body side is controlled. Not only does it require a special electrical connection contact between the detection device and the structure is complicated, but all medium- and long-focal-length barrel lenses must have separate drive motors. In addition to being expensive, the useful value of the motor installed on the camera body side is not being utilized.

In addition, in the autofocus camera disclosed in JP-A No. 55-129317, the main part of the autofocus mechanism is built into the film winder, but since the amount of driving force of the film winder is limited, There are cases where the focusing movement of the long focal length barrel lens is insufficient, and in that case, it is necessary to prepare various types of special adapters, which has the disadvantage that interchangeable lenses cannot be used freely. are doing.

Furthermore, in an autofocus type interchangeable lens camera that has an autofocus drive source on the camera body side, there are some subjects that cannot be automatically focused, so a means for switching to manual focus is required. In this case, if the drive source and the driven device of the lens system are directly connected, when the distance ring on the lens side is manually rotated, the drive source (including the motor) on the camera body side will also be rotated, causing a large load. Then,
This is a disadvantage for manual focus, which requires delicate adjustments.

As described above, conventional autofocus cameras of this type have various drawbacks, and in practical terms, they all have problems in the operability of attaching and detaching the camera body and the lens barrel.

In view of the above-mentioned points, an object of the present invention is to eliminate the need for a special focusing drive motor even in the case of a medium- or long-focal-length lens barrel, and moreover, to automatically perform focusing by attaching the lens barrel to the camera body. An object of the present invention is to provide an extremely convenient autofocus camera having a drive transmission connecting member to which a focusing mechanism is connected.

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 1 is a sectional view of a main part of an autofocus camera showing an embodiment of the present invention, and the autofocus camera 1 of this embodiment uses a relatively small interchangeable lens such as a wide-angle lens or a standard lens. There is. In the figure, reference numeral 2 denotes a lens frame that holds the photographing lens group L, 3 a helicoid screw provided on the rear outer peripheral surface of the lens frame 2, and 4
6 is a rotating frame as a driven device having a helicoid screw 5 screwed into the helicoid screw 3 of the lens frame 2 on its inner surface; 6 is a helicoid provided on its inner surface on the rear outer peripheral surface of the rotating frame 4; an outer helicoid frame provided with a helicoid screw 7 screwed into the screw 4a;
Reference numeral 8 denotes a gear provided on the outer circumferential surface of the rotating frame 4 near the middle of the front, 9 a protruding piece forming a pair of keys protruding in the vertical direction near the front end of the rotating frame 4, 1
0 is a set screw 10 on the rear end surface of the outer helicoid frame 6.
11 is a camera body mount frame which is fitted with the lens mount frame 10 by a well-known means; 12 is a lens mount frame having an anti-slip rubber band 13 fitted to the outer circumferential surface; A short cylindrical manual distance adjustment member 15 is formed with a gear 14 that meshes with the gear 8 of the rotating frame 4; 15 is formed at the rear of the manual distance adjustment member 12; a cylindrical part that fits into the
Reference numeral 16 denotes a filter mounting frame fitted to the front outer peripheral surface of the lens barrel 2, and 17 a ring rotatably fitted to the rear outer peripheral surface of the filter mounting frame 16, which has a smaller diameter. Distance display member shaped like
A narrow collar 17a is formed on the outer periphery of the narrow diameter portion at the rear of the distance display member 17, and a circumferential groove 12a is formed on the inner surface of the front portion of the distance adjustment member 12.
It is rotatably fitted to the Further, key grooves 18 in the optical axis direction are formed on the upper and lower sides of the inner surface of the same distance display member 17, and the protruding pieces 9 of the rotating frame 4 are respectively fitted into the key grooves 18. That is, the distance display member 17 moves together with the distance adjustment member 12 in the front-rear direction, and rotates together with the rotation frame 4 in the rotation direction. In addition, the filter mounting frame 16
A distance display marking line 19 is provided on the outer circumferential surface in the middle, and extends to the part where the diameter becomes smaller.The manual distance adjustment member 12 can be moved rearward as shown in FIG. I can now see without any trouble even when

At the bottom of the lens barrel configured as described above, a focusing drive mechanism on the lens barrel side, which is connected to a focusing drive mechanism disposed on the camera body side, is arranged as shown below. ing. That is, a through hole 10 is formed in the lower part of the outer helicoid frame 6 parallel to the optical axis.
A focusing drive shaft 20 on the lens barrel side is rotatably supported in b, and the rear part of the coaxial shaft 20 projects into the lens mount 10, and the rear end projects from the body mount 11 on the camera body side. A gear 32 that meshes with a drive transmission gear 31 that is integrally formed at the tip of the focusing drive shaft 30 on the camera body side.
are integrally formed. A gear 21 that meshes with the gear 8 of the rotating frame 4 is integrally formed at the front end of the drive shaft 20. An elastic coil spring 24 is interposed between the gear 21 and the outer helicoid frame 6, and the drive shaft 20 is given the habit of moving forward. The position shown in FIG. 1, in which the gear 21 comes into contact with the ring-shaped protrusion 25 as a clutch driving means formed to protrude from the rear surface of the distance adjusting member 12, that is, the position where the gear 21 meshes with the gear 8 of the rotating frame 4. It is becoming more and more restrained.

On the other hand, inside the camera body, as is well known, there is a movable reflector 2 that is tilted at 45 degrees with respect to the optical axis of the photographic lens L.
6 is disposed, and the object light image incident from the photographing lens L is reflected upward at right angles by the movable reflecting mirror 26 and formed into an image on the focusing glass 29, and this formed object light image is shown in the figure. It is designed to be observed with an eyepiece through a pentagonal Datsuha prism. A part of the subject light image passes through a semi-transparent part provided at the center of the movable reflecting mirror 26, and passes through an auxiliary reflecting mirror rotatably disposed vertically on the rear surface of the movable reflecting mirror 26. 27, and is imaged on the upper surface of a focus detection element 28 disposed at a position conjugate with the film surface below. The output signal detected by the focus detection element 28 is transmitted to the motor 3 disposed below the focus detection element 28 via an electric circuit (not shown).
It is designed to control the rotation of 3. The rotation of the drive shaft of the motor 33 is controlled by the intermediate gear train 3 for reduction.
4, the focusing drive shaft 30 on the camera body side
The rotation of the coaxial shaft 30 is transmitted to the focusing drive shaft 20 on the barrel lens side via a rotational drive transmission gear 32 that meshes with a rotational drive transmission gear 31. This rotation of the focusing drive shaft 20 rotates the rotating frame 4 via the gear 21 that is integral with the coaxial shaft 20 and the gear 8 of the rotating frame 4 that meshes with the gear 21. When this rotating frame 4 rotates, the lens frame 2 moves back and forth via the helicoid screw 5 of the same frame 4 and the helicoid screw 3 of the lens frame 2 screwed thereto, and the lens barrel lens L is brought into focus. It's becoming manipulated. At this time, that is, in the state shown in FIG. 1, the gear 14 of the manual distance adjustment member 12 is
Since the member 12 does not mesh with the gear 8, the distance display member 17 does not rotate.
Since the projecting piece 9 of the rotation frame 4 is fitted into the rotation frame 8, the rotation frame 4 rotates and the distance can be displayed on the distance display indicator 19. In this case, since the threading lead between the helicoid screw 7 of the outer helicoid frame 6 and the helicoid screw 4a of the rotating frame 4 is small, the meshing between the gear 8 of the rotating frame 4 and the gear 21 of the drive shaft 20 is difficult. They will not come off, and neither the manual distance adjustment member 12 nor the distance display member 17 will move back and forth.

Further, the lens frame 2 has an outer helicoid frame 6 in a hole 35 parallel to the optical axis, which is bored in a part of the rear part of the lens frame 2.
A guide pin 36 is inserted into the lower part of the guide pin 36, which is bent upward at a right angle, so that the guide pin 36 can move only in the front-back direction without rotating.

Next, the operation of the autofocus camera 1 configured as above will be explained. The above focus detection element 2
8, as is well known, detects the point where the amount of subject light incident from the photographing lens L is at its maximum as the focal point, and the motor 33 is rotated by the output signal until the amount of light reaches the maximum. The rotation of this motor 33 is decelerated and transmitted to the focusing drive shaft 30 on the camera body 23 side via the deceleration intermediate gear train 34, and the rotation of the drive shaft 30 is transmitted to the rotational drive transmission gear 31, the rotational drive Transmitted gear 32
is transmitted to the focusing drive shaft 20 on the lens barrel side. When this focusing drive shaft 20 rotates, the same axis 2
0 also rotates, and the rotating frame 4 is rotated via the gear 8 that meshes with the gear 21. When this rotating frame 4 rotates, the lens barrel 2, which has the helicoid screw 3 that is screwed into the helicoid screw 5 of the frame 4, is prevented from rotating by the pin 36, so it moves back and forth to the focusing position. When the photographing lens L reaches the in-focus position, the rotation of the motor 33 is stopped and the photographic lens L is stopped at the in-focus position.

Further, the autofocus camera 1 includes the manual distance adjustment member 12, so that focusing can also be performed manually. That is, when the manual distance adjustment member 12 is pushed toward the rear of the optical axis from the state shown in FIG. 1, as shown in FIG. 21 in the same direction against the elasticity of the coil spring 24, and the gear 21 and the gear 8 of the rotating frame 4 are moved.
At the same time as releasing the meshing with the manual distance adjusting member 1
Since the gear 14 of No. 2 meshes with the gear 8,
By manually rotating the member 12, the rotating frame 4 can be freely rotated via the gears 14 and 8. That is, the focus of the barrel lens can be adjusted manually. In addition, at this time, the distance display member 17
As described above, it operates integrally with the distance adjusting member 12 in the front-back direction and with the rotation frame 4 in the rotation direction. Further, the manual distance adjusting member 12 is adapted to be appropriately locked in the position shown in FIGS. 1 and 2 by a click stop mechanism (not shown).

Next, a connection mechanism for transmitting the rotation of the focusing drive motor 33 on the camera body side to the lens barrel side in the autofocus camera 1 of the present invention will be explained.

FIGS. 3 and 4 are diagrams showing an example thereof. The coupling method between the body mount 11 (see FIG. 1) of the autofocus camera in the above embodiment and the lens mount 10 on the lens barrel side is a so-called bayonet type. That is, both mounts 10,1
1 has a flange (not shown) consisting of an inwardly protruding edge with a notch at the tip thereof, and after the flange is fitted through the notch of the opposing mounts 10 and 11, it rotates, and the inner surface of both flange is rotated. This is a type in which both mounts 10 and 11 are fixed in close contact with each other in the front and rear direction. In FIGS. 3 and 4, a focusing drive shaft 91 corresponding to the focusing drive shaft 30 on the camera body side, which protrudes inward from the 11th surface of the body mount of such a bayonet type, protrudes from the 10th surface of the lens mount. The focusing drive shaft 20 on the lens barrel side
A drive shaft 92 corresponding to the lens barrel is arranged at a position where a drive gear 93 and a driven gear 94, which are integrally formed at the respective tips, mesh with each other when the lens barrel is installed in the camera body. has been done. and,
When the lens mount 10 is fitted into the body mount 11, the driven gear 94 is in the third position.
At the position of the dotted line in the figure, both mounts 10 and 11
is fixed, that is, when the lens mount 10 is rotated in the direction of the arrow 98, the drive gear 93
It's starting to fit together. That is, when the lens barrel is attached to the camera body, the gears 93 and 94 are automatically engaged, so that the focus drive shaft 30 of the focus drive motor is automatically moved toward the lens barrel side. It is connected to a focusing drive shaft 20 . Since the meshing direction of both gears 93 and 94 is designed to be closer to each other from the lateral direction, even if there is slight misalignment (in the axial direction or rotational direction), there is no problem in transmitting the rotational driving force, and the quality is stable. can get.

5 and 6 show another example of the above-described coupling mechanism, in which disk-shaped permanent magnets 95 and 96 are used in place of the driving gear 93 and driven gear 94 in FIGS. 3 and 4. It is designed to be integrally attached to the tips of both drive shafts 91 and 92. Both permanent magnets 95 and 96 face each other with a slight gap when the lens barrel is attached to the camera body, and both magnets 95 and 96 are radially magnetized. As shown in the figure, the N and S poles are coupled oppositely to each other. Since such a connection mechanism is not a mechanical connection, it is easy to attach and detach.

FIG. 7 is a sectional view of a main part showing still another example of the above-mentioned coupling mechanism. This connection mechanism is provided at the lower part of the lens mount 10 and body mount 11, and its main part is a connection member that connects the focus drive shaft 101 of the camera body and the focus drive shaft 102 of the lens barrel side. 103 and the connecting member 103
a release lever 104 for releasing the connection between the lens mount 10 and a release lever engaging member installed at one end of the release lever 104 and protruding from the rear surface of the lens mount 10 through a through hole 10b drilled in the lower part of the lens mount 10; The locking pin 105 and this locking pin 10
5 comprises a locking round hole 106 drilled in the lower front surface of the body mount, into which the camera body and the lens barrel are fitted.

The connecting member 103 is located at the left end (in the figure)
is the large diameter cylindrical part 103a, and the central part is the small diameter shaft part 10.
3b, the right end has a connecting groove 10 on its end surface.
7, and is rotatably supported by a bearing member (not shown), and a focusing drive shaft 102 on the lens barrel side is mounted in the cylindrical portion 103a. It is designed to fit in so that it can move forward and backward. Then, the cylindrical part 1
A key groove 108 in the tube axis direction is provided at the tip of 03a, and a pair of pin-shaped keys 109 implanted on the outer peripheral surface of the focusing drive shaft 102 are fitted into the key groove 108. It's getting old. Furthermore, the inner bottom surface of the cylindrical portion 103a and the focusing drive shaft 102
Although an elastic coil spring 110 is interposed between the connecting member 103 and the right end surface of the cylindrical portion 103a, the connecting member 103 has a tendency to move rightward. is the release lever 10
4, further movement is inhibited. The release lever 104 has a tendency to move to the right by an elastic coil spring 111 disposed between its base and an immovable member. It is restrained by contacting the inner surface of the mount 10. In addition, the locking pin 105
is moved to the left together with the release lever 104 against the elasticity of the coil spring 111 in conjunction with a known lens barrel attachment/detachment button (not shown), and its tip is placed within the mounting surface of the lens mount 10. It's starting to draw in.

On the other hand, at the tip of the focusing drive shaft 101 on the side of the camera body, a connecting portion 112 having a projection 113 that fits into the slot 107 of the connecting portion 103c of the connecting member 103 is connected to the focusing driving shaft 101. It is formed in one piece. Furthermore, when the lens barrel is attached to the camera body, the pin 10 is located on the surface of the body mount 11 corresponding to the point where the locking pin 105 is located.
A locking hole 106 into which 5 is inserted is provided.

As is clear from its structure, the coupling member 103 is fitted with the focusing drive shaft 102 so that it can move forward and backward, and its rotation is transmitted integrally with the same shaft 102.

Next, the operation of the connecting mechanism configured as described above will be explained. FIG. 7 shows a state in which the lens barrel is attached to the camera body.
When the locking pin 105 comes into contact with the surface of the body mount 11, the pin is inserted into the through hole 10b of the lens mount 10.
The release lever 104 is pushed to the left against the elasticity of the coil spring 111, and the lever 104 also moves the connecting member 103 to the left against the elasticity of the coil spring 110. Move to
The connecting portion 103c is also located at a point away from the connecting portion 112 of the focusing drive shaft 101 on the camera body side. When the lens mount 10 is rotated from the state where it is inserted into the body mount 11 to the mounted state, the locking pin 1
05 rotates in the direction of the arrow from the dotted line position to the solid line position, that is, the locking hole 1 of the body mount 11.
Reach position 06. Then, the locking pin 105 protrudes from the lens mount surface due to the elasticity of the coil spring 111, and fits into the locking hole 106 of the body mount 11, as shown in FIG.
At the same time that the lens barrel is fixed to the camera body, the release lever 104 also moves to the right in the state shown in the figure, and as a result, the connecting member 103 also releases the coil spring 110.
The connecting portion 103c moves to the right due to the elasticity of the
At that time, it comes into contact with the connecting portion 112 of the focusing drive shaft 101, which has reached the axis of the member 103. At this time, the grooves 107 of both connecting portions 103c and 112
Although the facing angles of the protrusions 113 and the protrusions 113 do not necessarily match, the first slight rotation of the drive shaft 101 causes the facing angles of the two to match and fit together. In this way, when removing the lens barrel from the state where the lens barrel is attached to the camera body, by pressing the attachment/detachment button of the lens barrel (not shown), the above-mentioned Since the locking pin 105 is pulled out from the locking hole 106, it can be removed after rotating the lens barrel. In this way, this coupling mechanism also works in conjunction with the attachment of the lens barrel to the camera body, and connects the focusing drive shafts 101 and 102 of both.
are automatically concatenated.

As described above, according to the present invention, in an autofocus camera that has a built-in driven device for moving a lens system and has a lens barrel that is detachable from the camera body, the rotation transmission shaft on the camera body side and the lens barrel are provided. A rotation transmission shaft on the lens barrel side is disposed parallel to the optical axis of the photographing lens, and a first clutch mechanism is disposed between the two axes, and a rotation transmission shaft on the lens barrel side and the drive of the driven device are further provided. A second switch is provided between the switching member for switching between automatic and manual operation and the driven device.
A clutch mechanism is provided, and the first clutch mechanism is connected by attaching the lens barrel to the camera body, and the rotation transmission axis on the lens barrel side is photographed by operating the switching member. Since the first and second clutches are engaged and disengaged by moving the lens in the optical axis direction, it is possible to switch between automatic and manual driving of the lens system in an autofocus camera. It is possible to obtain an autofocus camera whose mechanism can be simplified and the outer diameter of the lens barrel does not need to be increased.

Furthermore, when manually driving the lens system,
The load at that time can be reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts of an autofocus camera showing an embodiment of the present invention, FIG. 2 is an operational diagram of the autofocus camera shown in FIG. 1, and FIGS. FIGS. 5 and 6 are a plan view and an enlarged cross-sectional view of essential parts showing an example of a coupling mechanism in a focusing camera; FIGS. FIG. 8 is a plan view of the body mount in the connection mechanism shown in FIG. 7. FIG. 1... Automatic focus camera, 28... Focus detection element (focus detection device), 33... Motor, {31...
Rotational drive transmission gear, 32...Rotational drive transmitted gear} (rotational drive connection member).

Claims (1)

[Scope of Claims] 1. A camera body incorporating an automatic focusing drive device, and a lens barrel that includes a built-in driven device driven by the drive device to move a lens system, and is detachably attached to the camera body. An autofocus camera consisting of a rotation transmission shaft on the camera body side connected to the drive device and arranged parallel to the optical axis of the taking lens, and a lens barrel arranged parallel to the optical axis of the taking lens. A rotation transmission shaft on the side, and a rotation transmission shaft provided between the two transmission shafts, connected by mounting the lens barrel on the camera body, and directing the rotation transmission shaft on the lens barrel side in the direction of the optical axis of the photographing lens. a first clutch mechanism that disconnects the connection when moved; an automatic/manual switching member that switches between automatically and manually driving the driven device; the driven device; a second clutch mechanism disposed between the lens barrel side rotation transmission shaft and the automatic/manual switching member, and selectively connecting the rotation transmission shaft and the switching member to the driven device; - a clutch driving means provided on the manual switching member, which moves at least one of the two transmission shafts in the direction of the optical axis of the photographic lens in conjunction with the switching operation, and switching the switching member to the manual side; When the first clutch is disengaged, the switching member and the driven device are connected by the second clutch, and when the switching operation to the automatic side is performed, the first clutch is connected, and the second clutch is used to connect the rotation transmission shaft on the lens barrel side to the driven device. An autofocus camera characterized in that it is connected to a device. 2. The automatic/manual switching member is constituted by a manual distance adjusting member capable of a first movement of rotating around the photographing optical axis and a second movement of sliding parallel to the photographing optical axis. 2. An autofocus camera according to claim 1, wherein said transmission shaft is moved by two movements.