JPH048773B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a focusing device for a camera in which a method of operating a member for driving and controlling a photographic lens is improved.

[Prior Art] Various types of focusing devices for photographing lenses used in small cameras have been devised in the past, but all of them involve pressing the photographing lens member against a cam member with a spring or the like to ensure accuracy. , a helicoid is used to convert rotational operation into linear operation, and a large amount of extra load is required to drive the lightweight photographic lens member.

Moreover, the drive source is a mechanism that charges a spring manually or with a motor, etc., and uses the spring force to operate the photographic lens member, so it requires even greater driving force, making it difficult to construct a compact and lightweight focusing device. was extremely difficult.

Therefore, we proposed in Japanese Patent Application No. 59-258114 a so-called stepped cam member in which a stepped portion with a height in the optical axis direction is formed on the end face of a cylindrical portion, and a stepped cam member that separately moves the photographic lens in the optical axis direction. The function of the step cam member and the lens drive member can be separated by having a structure in which a lens drive member is brought into contact with the stepped portion of the cam member, and these members work together to focus the photographing lens. We devised a focusing device that operates with a small driving force source by distributing the driving force.

The step cam member is rotated around the optical axis by the power based on the distance measurement signal to select the step, and then the lens drive member is rotated and the spiral cam groove on the circumference is moved in the direction of the optical axis. The function is to set the photographing lens at its in-focus position by moving the pin of the photographing lens frame, which can only move straight ahead, and bringing it into contact with the step mentioned above.

In other words, the pin of the photographic lens frame is supported while being restrained by both the linear groove in the optical axis direction provided in the fixed part of the lens barrel and the aforementioned spiral cam groove, and when the lens drive member rotates, By slidingly contacting the slope of the spiral cam groove, the cam is moved in the optical axis direction by the force generated by the sliding contact.

[Problems to be Solved by the Invention] As mentioned above, the pin of the photographic lens frame comes into contact with the step cam which has already stopped due to the component force of the slope of the rotating spiral cam groove. Partly because the angle of inclination is relatively small, a large frictional force is generated due to the wedge action, and the slope of the grooved cam tends to be strongly pressed against the pin of the photographic lens frame.

Therefore, when the lens drive member is reversed to return the photographic lens to its initial position, a large rotational force is required, and if the power is obtained from a motor, the reverse rotation is impossible.

The present invention solves this problem and provides an improved camera focusing device that can reliably return the photographing lens to its initial position even with the power of a small motor.

[Means for solving the problem] The above object is to move the lens in the forward direction by driving a motor and stop it when it comes into contact with a stop member.
The focusing device then moves the lens in the backward direction to return the lens to its initial position, characterized in that a signal to move the lens in the forward direction is temporarily applied to the motor prior to a signal to move the lens in the backward direction. This is achieved by the camera's focusing device.

[Example] An example of the present invention is shown in FIGS. 1 and 2.

The figure shows the components of this device expanded in the optical axis direction. These components are built into the lens barrel of the camera as a unit and are driven by the power supply and control device provided on the camera body. , is something that is controlled.

Reference numeral 10 denotes an electromagnetic unit fixed within the lens barrel, and inside the electromagnetic unit are provided a first movable coil member (not shown) for controlling the exposure amount of the photographing optical system and a regulating pin 11 for regulating a locking member to be described later. The implanted second movable coil member 12 is accommodated in a state where it can rotate around the optical axis.

Reference numeral 20 denotes a lens guide attached to the front surface of the electromagnetic unit 10, which is composed of a flange portion 21 and a cylindrical portion 26, and has a detection pattern on the flange portion 21 to send lens position information to the aforementioned control device. A stop pawl 24, which is biased clockwise by a printed board 22 and a tension spring 23, is pivotally mounted. The stop claw 24 is prevented from rotating clockwise by the locking action of the regulating pin 11 of the electromagnetic unit 10 passing through the flange portion 21.

On the other hand, three straight grooves 27 are provided on the circumferential surface of the cylindrical portion 26 at equal intervals in the optical axis direction, and guide pins 51 of the photographic lens 50 slidably fitted into the inner circumferences thereof are respectively fitted. The photographic lens 50 is held so that it can move forward and backward in the optical axis direction.

Reference numeral 40 denotes a lens driving member rotatably fitted to the outer periphery of the cylindrical portion 26 of the lens guide 20, and three cam grooves 42 provided in the cylindrical portion 41 fit the guide pins 51 of the photographic lens 50, respectively. It cooperates with the straight groove 27 to form a state in which the straight position of the photographic lens 50 is restricted. Further, the lens driving member 40 is connected to the pinion 61 of the motor 60 via a gear portion 47 provided on the flange portion 46.
This allows for clockwise rotation from the illustrated position and reverse rotation for return.

Reference numeral 30 denotes a stop member, that is, a lens positioning member, which is fitted onto the cylindrical portion 41 of the lens driving member 40, and the guide pin 51 of the photographic lens 50 is brought into contact with the end face of the stop member 30, so that the photographic lens 50 is
Three step cams 31 are provided at positions corresponding to the guide pins 51 for setting the lens to a predetermined focal position. The lens positioning member 30 and the lens drive member 40 are such that the tip of a pressing spring 33 attached to the protrusion 32 of the lens positioning member 30 engages with a V-shaped notch 48 provided in the flange portion 46 of the lens drive member 40. By doing so, they are integrated and rotated simultaneously by the motor 60.

In this state, the cam groove 42 of the lens driving member 40 is arranged substantially parallel to the step cam 31 of the lens positioning member 30, and the cam groove 42
It is assumed that the guide pin 51 of the photographing lens 50, which is regulated by the guide pin 50, is provided at a position slightly spaced apart from the stepped cam 31 so that it does not come into low contact with the stepped cam 31.

Further, a contact piece 35 is attached to the other protrusion 34 of the lens positioning member 30, and as the lens driving member 40 rotates, the contact piece 35 slides on the intermittent circuit pattern on the printed board 22 of the lens guide 20. By doing so, a pulse signal is sent to the control device, and the other portion is formed with pawl teeth 36 which engage the stop pawl 24 which is activated by a signal from the control device.

The lens driving member 40 and the lens positioning member 30 include a front surface of the flange portion 21 of the lens guide 20 and three pillars 71 on the flange portion 21.
The holding plate 70 is held between the holding plate 70 and the back surface of the holding plate 70 attached via the holding plate 70, and is rotatably supported.

FIG. 3 shows the motor drive circuit. M in the figure is the motor 60 in FIG. 1. When a signal is input to terminal L from the control circuit, the transistor
TR ₁ and TR ₃ become conductive, motor M rotates forward, and terminal R
When a signal is input to , transistors TR ₂ and TR ₄ become conductive and the motor M rotates in reverse.

Next, its operation and function will be explained with reference to FIG.

A distance measuring device detects a subject distance in conjunction with the operation of operating a camera release, and the information is input to the aforementioned control device.

Next, before starting the focusing operation, in order to confirm that the lens positioning member 30 is in a controllable state, the second movable coil member 12 is previously energized in the positive direction A1 to regulate it. Rotate the pin 11 clockwise and rotate the stop pawl 24 counterclockwise to remove the pawl teeth 3 of the lens positioning member 30.
6. Perform the action to release the lock.

With a slight delay in the rotation of the regulation pin 11, the motor 60 begins to rotate counterclockwise due to the positive energization B1, and the lens drive member 40 and lens positioning member 30 are integrally moved clockwise via the pinion 61. direction.

Due to this action, the photographing lens 50 recedes linearly, and at the same time, the contact piece 35 and the printed board 22 begin to come into sliding contact, and the position of the photographing lens is input to the control device using a pulse signal C1.

In the control device, a comparison is made with a signal set in advance corresponding to the distance information from the distance measuring device, and if they match, the rotation of the motor 60 is temporarily stopped, and at the same time, the rotation of the motor 60 is stopped, and at the same time, the signal is energization A2 is performed in the opposite direction.

As a result, as the regulating pin 11 rotates counterclockwise, the stop claw 24 again locks the lens positioning member 30 to stop its rotation and stop the stepped cam 31 at a desired position.

Subsequently, the motor 60 restarts its rotation by applying current B2 in the positive direction again, and the lens driving member 40 is further rotated clockwise, so that the pressing spring 33 and the notch 48 are disengaged, and only the lens driving member 40 is turned. It is rotated by itself.

As the lens driving member 40 continues to rotate, the guide pin 51 of the photographing lens 50, which was held at a position apart from the step cam 31 as described above, comes into contact with a predetermined step of the step cam 31 by the cam groove 42. After the photographing lens 50 is set at a position on the optical axis corresponding to the distance information of the distance measuring device, the motor 60 stops after a predetermined time, and its operation, that is, the action up to focusing is completed. Become.

When the focus adjustment of the photographic lens 50 is thus completed, the first movable coil member (not shown) is activated to perform exposure, and upon completion of photographing, upon receiving the signal, the second movable coil member 12 is energized in the positive direction again A3. Then, the stop claw 24 is removed and the lens positioning member 30 is released in the same way as in the case described above.

Next, the motor 60 starts to reverse in order to return the focusing device to the initial position, but in the present invention, before starting the reverse rotation of the motor 60, a pulse current B3 in the positive direction is first applied, and then a continuous pulse current is applied. By energizing B4 in the opposite direction, the motor 6
0 by applying reaction torque due to inertia to the cam groove 4.
The lens driving member 40 is configured to overcome the frictional resistance generated between the lens driving member 2 and the guide pin 51, and to ensure that the lens driving member 40 returns to its initial position by reverse rotation.

The effect of the pulse energization B3 increases even if it is repeated several times in succession, and the cam groove 4
It is desirable that the angle of inclination is determined according to the angle of inclination of item 2, etc.

In this way, the photographing lens 50 moves linearly forward due to the reverse rotation of the motor 60, while the lens positioning member 30 also becomes integral with the lens driving member 40 as the pressing spring 33 and the notch 48 engage again in the process. As a result, they each return to their initial positions.

Note that the pulse signal C2 is applied to the contact piece 35 and the printed board 2 when the lens positioning member 20 returns.
2, the reverse rotation of the motor 60 is stopped after a certain amount of time has elapsed since the signal is terminated, taking into account the bounce of the lens driving member 40 etc. after returning to the initial position.

[Effects of the Invention] According to the present invention, the operation of the control member that drives the photographing lens in the focusing device, especially the return operation to the initial position, can be performed reliably, and therefore, highly reliable focusing can be achieved. The equipment has now been provided.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a focusing device according to the present invention.
Figure 2 shows the operating sequence of the device. FIG. 3 is a drive circuit diagram of the device. DESCRIPTION OF SYMBOLS 10... Electromagnetic unit, 12... Second movable coil member, 20... Lens guide, 22... Printed board, 30... Lens positioning member, 31... Step cam, 33... Pressing spring, 35... Contact Piece, 36...
...Claw tooth, 40...Lens drive member, 42...Cam groove, 50...Photographing lens, 51...Guide pin, 60...Motor.

Claims (1)

[Claims] 1. A regulating member that is integrally formed with a photographic lens and has a guide pin that is provided on the outer periphery of the lens and protrudes in a direction perpendicular to the optical axis, and a straight guide means for moving the guide pin straight in the optical axis direction. a lens positioning member having an abutment surface that restricts movement of the guide pin in the optical axis direction; and a lens positioning member that rotates about the optical axis of the lens and slides the guide pin on the linear guide means of the restriction member. A lens driving member including a cam portion that reciprocates the lens in the optical axis direction, and a control means for driving and controlling the lens driving member with a motor, the control means setting the lens at a focusing position. When doing so, the cam portion of the lens driving member sends a signal to the motor to move the guide pin in the forward direction, presses the guide pin so as to abut against the abutment surface of the lens positioning member, and To release from the focus position,
A focusing device for a camera, wherein a signal for moving the guide pin in a forward direction is temporarily applied to the motor by a cam portion of the lens driving member prior to a signal for moving the guide pin in a backward direction.