JPS6346419A - Autofocusing camera - Google Patents

Abstract

PURPOSE:To use a focusing mechanism in a camera body for an interchangeable lens as it is by providing the titled camera with a rotation transmitting shaft on the lens barrel side which is driven by a rotation transmitting shaft on the camera body, a machine value/electric value converting means built in the lens barrel, a motor driving circuit, and a lens driving motor. CONSTITUTION:The optical image of an object passed through a photographing lens is formed on a focusing element through an auxiliary reflecting mirror. The element rotates a focusing driving motor and the rotation is transmitted to a lens barrel side rotation transmitting shaft 51 united with a driven gear 51a through an intermediate gear train and a camera body side rotation transmitting shaft. Interlocking with the rotation of the shaft 51, a driving shaft 52 of a generator (mechanical valve/electric value converting mean) 53 around which a driven gear 52a engaged with a driving gear 51b formed unitedly with the shaft 51 is formed is rotated, the rotation of the shaft 51 is converted into an electric signal by the generator 53 and a lens driving motor 55 is rotated through a servo motor driving circuit 54.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an automatic focusing, adjustable camera, in particular, a drive device for automatic focusing is disposed on the camera body side,
The present invention relates to an automatic focusing camera that has a built-in driven device that moves a lens system toward an interchangeable lens barrel that is detachably attached to the camera body.

[Prior Art] As is well known, this type of autofocus camera has conventionally
Various methods have already been proposed. For example, in a single-lens reflex camera with interchangeable lenses, the autofocus device of this camera usually has a focusing drive device built into the camera body, and a rotational drive transmitted from this drive device to the lens barrel. There is a built-in driven device that is actuated by a force to focus the lens. The camera body and the lens barrel are connected by their mounts, and this connection connects the driving force transmission mechanism (coupler) between the two via a clutch, so that the drive force transmission mechanism (coupler) for both is connected via a clutch, and the drive force transmission mechanism (coupler) for both is connected via a clutch. The rotational driving force is transmitted to the lens barrel side.

[Problems to be Solved by the Invention] Incidentally, in an autofocusing type single-lens reflex camera in which a wide variety of interchangeable lenses can be exchanged, the arrangement of an autofocus drive source poses a problem.

In general, for compact wide-angle and standard lenses, the installation space for the drive source is small and the price is low, so it is advantageous to have it built into the camera body. If the driven object is located further away from the main body, it is advantageous to have the drive source built into the lens side, and since the lens itself is expensive, there is no cost problem.

Therefore, normally only large lenses have a built-in drive source, and ordinary lenses have a built-in drive source in the camera body, but this requires an extra electrical contact for signal exchange between the camera body and the lens barrel. This causes reliability deterioration such as contact instability and increases the negative cost IU1 on the camera body side. Furthermore, a CPU for controlling received signals is also required on the lens side, and signal processing on the camera body side also becomes complicated.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an autofocus camera which eliminates the above-mentioned drawbacks of the prior art.

[Means and effects for solving the problems] The present invention has the following features:
In order to achieve the above object, in an autofocus camera that has a camera body with a built-in drive device for autofocus adjustment, and a lens barrel with a built-in driven device for moving the lens system, the drive device is A rotation transmission shaft on the connected camera body side, a rotation transmission shaft on the lens barrel side driven by the rotation rotation axis on the camera body side, and a rotation transmission shaft built in the lens barrel and driven by the rotation transmission shaft on the lens barrel side. A mechanical quantity/electrical quantity conversion means driven by a transmission shaft, a motor drive circuit built in the lens barrel and converting the output from the conversion means into a signal for driving the motor, and a motor drive circuit built in the lens barrel and configured to convert the output from the conversion means into a signal for driving the motor. It is characterized by comprising a lens drive motor driven by receiving the output of the circuit.

[Example] First, before explaining the present invention in detail, an example of an automatic focusing camera to which the present invention is applied will be explained with reference to Fig. 3.4.

This autofocus camera 1 is constructed as shown in FIG. That is, in FIG. 3, reference numeral 2 denotes a lens frame that holds the photographing lens L, 3 denotes a vericoid screw provided on the rear outer circumferential surface of the lens frame 2, and 4 denotes a screw threaded into the helicoid screw 3 of the lens frame 2 on the inner surface. a rotating frame provided with a matching helicoid screw 5;
Reference numeral 6 denotes an outer helicoid frame having a helicoid screw 7 on its inner surface that is screwed into the vericoid screw 4a provided on the rear outer peripheral surface of the rotating frame 4, and 8 refers to the outer periphery of the rotating frame 4 near the middle of the front. Gears 9 provided on the surface are projecting pieces 1 forming a pair of keys projecting upward and downward near the front end of the rotating frame 4.
0 is a lens mount frame fixed to the rear end surface of the outer helicoidal frame 6 by a set screw tOa, 11 is a camera body mount frame that fits into the lens mount frame 10 by known means, and 12 is a lens mount frame that slides onto the outer peripheral surface. A manual distance adjustment member 15 is a short cylindrical distance ring for manual focusing, into which a rubber band 13 is fitted, and a gear 14 that meshes with the gear 8 of the rotating frame 4 is formed on the inner peripheral surface. Formed at the rear of the distance adjustment member 12, the lens mount frame 10
16 is a cylindrical portion that fits into the front inner surface of the lens frame 2.
A filter mounting frame fitted onto the front outer peripheral surface of the frame, 17
is a ring-shaped distance display member that is rotatably fitted to the outer circumferential surface of the rear part of the filter mounting frame 16, which has a smaller diameter; A narrow collar 17a is formed, and is rotatably fitted into a circumferential groove 12a bored on the inner surface of the front portion of the distance adjusting member 12. Moreover, key grooves 18 are bored in the inner surface of the same distance display member 17 in the optical axis direction at the top and bottom, and the protruding pieces 9 of the rotating frame 4 are fitted into the key grooves 18, respectively. 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. Further, on the outer peripheral surface of the filter mounting frame 16 in the middle, a distance display indicator 19 is provided that extends to the part where the diameter is further reduced. As such, it can be seen without any problem even when moved backwards.

At the bottom of the lens barrel configured in this way, a focusing drive mechanism on the lens barrel side that is connected to a focusing drive mechanism arranged on the camera body side is arranged as shown below. There is. That is, the focusing drive shaft 2 on the lens barrel lens side is located in the through hole 10b that is bored in the lower part of the recoid frame 6 in parallel with the optical axis.
The rear part of the coaxial shaft 20 projects into the lens mount 10, and the rear end of the coaxial shaft 20 is connected to the tip of a focusing drive shaft 30 on the camera body side that projects from the body mount 11 on the camera body side. A gear 32 that meshes with the integrally attached drive transmission gear 31 is integrally attached. A gear 21 that meshes with the gear 8 of the rotating frame 4 is integrally attached to the front end of the drive shaft 20. An elastic coil spring 24 is interposed between the gear 21 and the outward recoid frame 6.
Although the drive shaft 20 is given the habit of moving forward,
The front surface of the gear 21 comes into contact with a ring-shaped protrusion 25 formed to protrude from the rear surface of the distance adjusting member 12, and the third
The gear 21 is restrained at the position shown in the figure, that is, the position where the gear 21 meshes with the gear 8 of the rotating frame 4.

On the other hand, as is well known, there is a photographic lens L inside the camera body.
A movable reflecting mirror 26 tilted by 45'' with respect to the optical axis of the camera is disposed, and the light image incident from the photographing lens L is reflected upward at 100 degrees by the bipedal movable reflecting mirror 26. Then, the image is formed on a focusing glass 29, and this formed histogram is observed through an eyepiece lens through a pentagonal Datsuha prism (not shown). In addition, a part of the above-mentioned photographic light image passes through a semi-transparent part provided in the center of the movable reflecting mirror 26, and an auxiliary light image provided vertically and rotatably on the rear surface of the movable reflecting mirror 26 is transmitted. The light is reflected downward by a reflecting mirror 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 cable 28 controls the rotation of a motor 33 which is a drive source disposed below the focus detection cable 28 via an electric circuit (not shown). The rotation of the drive shaft of the motor 33 is decelerated and transmitted to the focusing drive shaft 30 on the camera body side through the deceleration intermediate gear train 34, and the rotation of the same shaft 30 meshes with the rotational drive transmission gear 31. Rotational drive wave transmission gear 3
2 to the focusing drive shaft 20 on the barrel lens side. 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 helicoid screw 5 of the open frame 4 and the lens frame 2 screwed together
The lens frame 2 is moved back and forth through the helicoid screw 3, and the photographic lens L is focused. At this time, in the state shown in FIG. 3, the gear 14 of the manual distance adjustment member 12 is not engaged with the gear 8 of the rotating frame 4, so the member 12 does not rotate, but the distance display member 17 Since the protruding piece 9 of the rotating frame 4 is fitted into the key 18, it can be rotated by the rotation of the rotating frame 4, 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 crusher 6 and the helicoid screw 4a of the rotating frame 4 is small, the gear 8 of the rotating frame 4 and the gear 21 of the drive shaft 20 are There is no possibility that the manual distance adjustment member 12 and the distance display member 17 will move back and forth.

Further, the lens frame 2 is installed outwardly at the bottom of the recoid frame 6 in a hole 35 parallel to the optical axis, which is bored in a part of its rear part, and is folded forward at a right angle. Since the bent guide pin 36 is fitted, it is possible to move only in the front-back direction without rotating.

Next, the operation of the autofocus camera 1 configured as above will be explained. As is well known, the focus detection element 28 detects the point where the amount of light from the object incident from the photographing lens L is at its maximum as the in-focus point, and uses its output signal to operate the motor 33 until the amount of light from the photographic subject reaches its maximum. Rotate. The rotation of this motor 33 is controlled by the speed reduction intermediate gear train 3.
4 to the focusing drive shaft 30 on the camera body 23 side, and the rotation of the drive shaft 30 is transmitted through the rotational drive transmission gear 312 and the rotational drive wave transmission gear 32.
The signal is transmitted to the focusing drive shaft 20 on the lens barrel side. When this focusing drive shaft 20 rotates, a gear 21 integrated with the same shaft 20 also rotates, and the rotation frame 4 is rotated via a gear 8 meshing with the same gear 21. When this rotating frame 4 rotates, the opening frame 4
Since the rotation direction of the lens barrel 2, which has the helicoid screw 3 screwed into the helicoid screw 5 of When the focus position is reached, the motor 3
By stopping the rotation in step 3, the lens stops 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 adjusting member 12 is pushed in the direction of the arrow from the state shown in FIG. The gear 21 is pushed in the same direction against the elasticity of the spring 24 to disengage the gear 8 of the rotating frame 4, and the gear 1 of the manual distance adjustment member 12 is moved.
4 meshes with the gear 8, so by manually rotating the shaft 12, the rotating frame 4 can be freely rotated via the gear 14.8. That is, it is possible to manually adjust the focus of the barrel lens.

At this time, the distance display member 17 operates integrally with the distance adjusting member 12 in the front-back direction and with the rotation frame 4 in the rotation direction, as described above. In addition, manual distance adjustment member 1
2 is adapted to be appropriately locked at the positions shown in FIGS. 3 and 4 above by a click stop mechanism (not shown).

Next, a practical example of the present invention applied to the autofocus camera configured as described above will be explained with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view of essential parts of an automatic focusing camera according to the present invention. The autofocus camera 50 of this embodiment uses a super-telephoto interchangeable lens. The configuration of the camera body in this case is completely the same as that shown in FIG. 3 above, so it is omitted.

In the focusing drive mechanism of a super-telephoto lens, the lens barrel is extremely large, so it cannot be driven by a small-output motor and power battery built into the camera body. Therefore, in the present invention, the focusing mechanism on the camera body side is used as is, and in addition, 1;
(See Fig. 3) A drive shaft 51 on the lens barrel side connected to the lens barrel drives a generator 53 disposed inside the lens barrel, and the generator 53 controls the rotation of the drive shaft 51 by electrical signals. The servo motor circuit 54 converts the output into voltage and amplifies it, and a powerful power supply battery 61 is housed in the lens barrel.
The servo motor 55 is rotated to move the lens barrel and focus.

Next, the focusing mechanism of the lens barrel of the autofocus camera 50 will be explained with reference to FIG. In the figure, reference numeral 41 denotes a fixed barrel that supports a lens frame 43 that moves back and forth, allowing the lens frame 43 to move forward and backward, 42 is a lens mount member formed into a circular tube at the rear end of the fixed barrel, and 44 is the rear of the two-legged fixed barrel 41. A pipe-shaped light-shielding tube 51 whose base is fixed to the end and extends inward of the fixed tube 41 is attached to the lower part of the inward flange formed at the rear end of the bipedal fixed tube 41 in row f along the optical axis. It is rotatably supported in a drilled through hole 41a, and integrally has a drive gear 51a at its rear end that meshes with the drive gear 32 of the focusing drive shaft 30 (see FIG. 3) on the camera body side. A rotary drive transmission shaft 54 is provided near the rear of the fixed cylinder 41, and a drive gear 51b that meshes with the gear 52a of the limb drive shaft 52 of the generator 53 is integrally attached to the front end thereof. It is disposed on the rear surface of the inward tsuba, receives the electric signal from the generator 53, converts it into voltage, amplifies it, and powers the servo motor 5.
Servo motor drive circuit and parts for driving 55
is a servo motor, which is disposed in a gear box 59 provided at the lower part of the fixed cylinder 41, with its drive shaft 55a being horizontal and perpendicular to the optical axis. 56 is an intermediate gear train for decelerating the rotation of the servo motor 55 and transmitting it to the binion 57; 58 is the binion 5 whose both ends are fixed to the rear lower surface of the lens frame 43 with mounting screws 60;
A horizontally elongated rack member 61 engages with the gear box 59, and 61 indicates a power source battery stored in a battery storage chamber 62 provided adjacent to the gear box 59.

Although not shown, the bottom plate of the gear box 59 has manual and manual controls for switching the focusing operation between automatic and manual.
An automatic switching switch and an operating switch for electric focusing are provided, which change the direction of rotation of the servo motor 55 in either forward or reverse direction and move the lens back and forth when the focusing operation is switched to manual.

The autofocus camera 50 configured as described above operates as follows.

The function of the focusing mechanism on the camera body side of this autofocus camera 50 is the same as that of the zero dynamic focus camera 1 shown in FIG. 3. That is, in FIG. 3, the photographic light image that has passed through the photographic lens L is reflected downward at a right angle by the auxiliary reflection mirror 27, and is reflected downward at a right angle by the auxiliary reflection mirror 27, and is reflected by the focusing beam 2 disposed below.
The image is formed on the surface of 8. Then, the element 28 detects whether or not the formed portrait light image is focused, and rotates the focusing drive motor 33 until it is focused. Same motor 3
3 is decelerated through an intermediate gear train 34 and transmitted to a focusing drive shaft 30 on the camera body side. The rotation of this focusing drive shaft 30 is transmitted to a focusing drive shaft 51 on the lens barrel side that is integrated with the driven gear 51a (see FIG. 1) that meshes with a driving gear 32 that is integrated with the same shaft 30. This rotation of the focusing drive shaft 51 causes the drive gear 51 integrated with the same shaft 51 to
A driven gear 52a that meshes with b is formed on the peripheral surface.
The drive shaft 52 of the generator 53 rotates, and the generator 53 converts the rotation of the focus drive shaft 51 into an electrical signal, which is then sent to the servo motor 5 via the servo motor drive circuit 54.
Rotate 5. The rotation of the servo motor 55 rotates a pinion 57 via a reduction gear train 56, which causes the rack member 58 that meshes with the pinion 57 to move in the front and rear directions, thereby moving the lens frame 43 in the front and rear directions.

This movement of the lens barrel 43 in the front and back direction is performed as the focus detection element 28 detects focus, and at the point when focus is achieved, the rotation of the focus drive motor 33 is stopped. Therefore, the lens barrel 43 stops at the focused position, and the camera 50 is automatically focused.

In this way, even when a super-telephoto lens that cannot be driven by the focusing drive motor and power battery installed on the camera body side, a separate drive motor is installed on the lens barrel side. With this arrangement, the focusing drive mechanism including the focusing drive motor and power battery on the camera body side can be used as is.

In the autofocus camera 50, when focusing is to be performed manually, the manual/automatic changeover switch (not shown) is used to switch to manual operation, and the servo motor is used instead of the focusing drive motor 30 on the camera body side. motor 55
By directly operating the lens barrel and rotating it left and right using an operation switch (not shown), focusing by moving the lens barrel in the front-rear direction can be performed electrically. It should be noted that if the shaft of the pinion 57 is made to protrude outside and a rotation knob is provided at the tip thereof, a manual operation without using the servo motor 55 can be achieved.

FIG. 2 shows an example of the electrical circuit of the generator and servo motor shown in FIG. 1 above. This electric circuit includes a power source battery E1 for driving the servo motor 55. E2 and
This motor 55 [! T! The generator 53 and the NPN transistor Q for controlling iIt:
, Q , NPN type transistors Q , Q
It is made up of. ” - One output terminal of the generator 53 is connected to the servo motor 5 through the connection point of the batteries E, E2.
The other output terminal of the generator 53 is connected to the bases of the transistors Q 1 and Q 1 tot 102 . Emitters of transistors Q and Q
ot 102 are both connected to one output terminal of the generator 53, and the collector of the transistor Q101 is connected to the transistor Q1.
The base of transistor Q102 is connected to the base of transistor Q103, and the collector of transistor Q102 is connected to the base of transistor Q104. The collectors of both transistors Q103'Q1.04 are both connected to the other input terminal of the servo motor 55, the emitter of transistor Q1o3 is connected to the positive electrode of battery E1, and the emitter of transistor Qlo4 is connected to the negative electrode of battery E2. There is.

The electric circuit of this example constructed in this way operates as follows. That is, if the output voltage of the generator 53 becomes polarized as shown in the figure due to the rotation of the drive shaft 51 due to the rotation of the focusing drive motor 33 (see FIG. 3) on the camera body side, then the polarity of the output voltage of the generator 53 becomes as shown in the figure. The emitter voltage becomes higher than the base voltage, and transistor Qlot is turned off.

Transistor Q102 is turned on. Then battery E 2
-1" Emitter of transistor Q102 Base of collector transistor Q104 of transistor Q102 -
Current flows with the emitter battery E2 of the same transistor Q104, turning on the transistor Q1o4, so that
Battery E2 → Servo motor 55 - Transistor Q104
Current flows from the collector of the transistor Q104 to the emitter of the battery E2, and the servo motor 55 rotates in one direction. This rotation is stopped 1- when the focus drive motor 33 (see FIG. 3) on the camera body side is controlled by the focus detection element 28 and stopped. Furthermore, if the focusing drive motor 33 rotates in the opposite direction, the generator 53 also rotates in the opposite direction, so the transistor Q
, Q are turned on, and the thermomotor 5 is turned on by the battery E1.
5 rotates in the opposite direction, and the lens barrel 43 stops when the focusing drive motor 33 stops.
to the focus position.

[Effects of the Invention] As described above, according to the present invention, (1) Even when using an extra large interchangeable lens such as a super-telephoto lens, the camera body can be easily used by simply incorporating an auxiliary motor and battery into the lens. The focusing mechanism can be used as is.

(2) Even with interchangeable lenses that pose a large load, there is no need for electrical contacts for signal transmission and reception, and the lenses are securely loaded, resulting in high reliability.

(3) The negative cost and space on the camera body side are almost zero.

Remarkable effects such as

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view of essential parts of an automatic focusing camera showing an embodiment of the present invention, FIG. 2 is an electrical circuit diagram of the automatic focusing camera shown in FIG. 1, and FIG. FIG. 4 is a sectional view of a main part showing an example of an autofocus camera to which the present invention is applied. FIG. 4 is an operational diagram of the autofocus camera shown in FIG. 3 above.

Claims (1)

[Scope of Claims] An automatic focusing camera having a camera body incorporating a driving device for automatic focusing, and a lens barrel incorporating a driven device for moving a lens system, which is connected to the driving device. a rotation transmission shaft on the camera body side, a rotation transmission shaft on the lens barrel side that is driven by the rotation transmission shaft on the camera body side, and a rotation transmission shaft built in the lens barrel and driven by the rotation transmission shaft on the lens barrel side. a motor drive circuit built into the lens barrel to convert the output from the conversion means into a motor drive signal; and a motor drive circuit built into the lens barrel to convert the output of the drive circuit into a signal for driving the motor. An automatic focusing camera characterized by comprising: a lens drive motor that is driven by the lens.