JPH067215B2 - Shatter drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a shutter drive of a camera in which the drive of a single motor is controlled so that the shutter is operated after the photographing lens is set to the in-focus position. It relates to the device.

[Conventional technology]

As a shutter drive device that has been recently proposed, there is a shutter drive device that performs focus adjustment and shutter control only by controlling drive of a stepping motor. In this shutter drive device, the stepping motor for rotating the shutter drive ring for shutter operation is also used for driving the focus adjustment ring for positioning the photographing lens, and the focus adjustment is performed before the shutter is operated. I'm trying to do. Therefore, a clutch mechanism is provided between the shutter drive ring and the focus adjustment ring, and the focus adjustment ring is connected to the shutter drive ring via the clutch mechanism up to a predetermined focus position determined by the distance measuring device. The clutch mechanism is disengaged when the focus adjustment ring reaches the predetermined focus position, and the focus adjustment ring is held at that position by the locking member. Then, the shutter is operated by continuously driving the stepping motor to rotate only the shutter drive ring.

By the way, in the shutter drive device configured as described above, if the engagement of the clutch mechanism can be released by the reverse rotation of the shutter drive ring, that is, the reverse rotation of the stepping motor, another electromagnetic device such as a magnet is used. Without this, focus control and shutter operation control can be performed only by controlling the drive of the stepping motor. Then, the driving of the stepping motor can be controlled by the microcomputer according to a series of sequence programs, and the configuration of the shutter driving device including the electrical configuration can be simplified.

[Problems to be solved by the invention]

However, when the stepping motor is reversely rotated in the course of normal rotation and thereby disengages the clutch mechanism, if the rotation amount in the reverse direction is insufficient, the clutch The mechanism cannot be disengaged and the focus adjustment ring cannot be positioned.
Further, if the amount of rotation in the reverse direction is too large, it is not preferable because it wastes time until the shutter is operated after the focus adjustment is completed.

The present invention has been made in view of such a technical background, and a shutter drive ring is driven by a motor controlled by a microcomputer according to a series of sequence programs, and is driven by the shutter drive ring via a clutch mechanism. When the focus adjustment ring is rotated to a predetermined focus position, the motor is always rotated in the reverse direction so that the clutch mechanism held in the engagement position until then can be released reliably and in a short time. It is an object of the present invention to provide a shutter drive device according to the above.

[Means for solving problems]

In order to achieve the above object, the present invention is configured such that the drive of a motor for rotating a shutter drive ring is controlled by a microcomputer according to a predetermined drive program, and the shutter drive ring is provided with a clutch mechanism. When the focus adjustment ring that is interlocked with the motor is rotated to the in-focus position detected by the distance measuring device, the motor is rotated in the reverse direction by a predetermined rotation amount preset in the drive program. When the motor is reversely rotated by a certain amount in this way, the engagement of the clutch mechanism is disengaged and the focus adjustment ring is not rotated but is held at the same position, that is, the in-focus position. The forward rotation is started, and the shutter is operated accordingly.

A motor for rotating the shutter drive ring may be a stepper motor, a servo motor or a DC motor.
A motor can also be used.

An embodiment of the present invention will be described below with reference to the drawings.

〔Example〕

In FIG. 1 showing an embodiment of the present invention, a sleeve 2 is provided on a shutter substrate 1 so as to project therefrom. The sleeve 2 is formed with two outer peripheral surfaces 2a and 2b having different outer diameters. The outer peripheral surface 2a having a large diameter is provided with a shutter drive ring 3 and the outer peripheral surface 2b having a small diameter is provided with a focus adjusting ring 5, respectively. It is movably attached. The focus adjustment ring 5 has a large diameter outer peripheral surface 2.
It is in contact with the front surface 2c of a and is always rotated in a constant plane.
Further, the thickness of the outer peripheral surface 2a having a large diameter is determined by the shutter drive ring 3
And a gap is formed between the shutter drive ring 3 and the focus adjustment ring 5.

A clutch lever 7 rotatable around a shaft 6 is attached to a part of the shutter drive ring 3 and is biased counterclockwise by a spring 8. A pin 9 is planted in the clutch lever 7. Shutter drive ring 3
Tooth rows 11 and 12 are formed on the outer periphery of the. A gear 16 driven by a stepping motor 13 via gears 14 and 15 meshes with the tooth row portion 11, and a gear 18 integrated with a disc 17 meshes with the other tooth row portion 12. ing.

Pins 19 are planted in the disc 17. The pin 19 swings the interlocking lever 20 in the counterclockwise direction in the process of rotating the disk 17 together with the gear 18 in the clockwise direction. By rotating the interlocking lever 20 in the counterclockwise direction, the shutter drive pin 23 implanted in the interlocking lever 20 penetrates the slot 24 formed in the shutter substrate 1 to operate the shutter blade drive mechanism 25. It has become.

A cam surface 28 whose height gradually increases toward the front surface side is formed on the front surface side of the focus adjustment ring 5 which is rotated in a constant plane with the front end surface 2c of the outer peripheral surface 2a having a large diameter as an opposition.
Further, on the outer circumference of the focus adjustment ring 5, clutch teeth 29 are formed and projections 30 are provided. A locking claw 33 of a locking lever 32 pivotally mounted on a support shaft 31 planted in the shutter base plate 1 is engaged with the clutch teeth 29. The clutch teeth 29 and the locking claws 33 form a one-way clutch, and the locking claws 33 prevent the focus adjusting ring 5 from being returned in the clockwise direction by the bias of the spring 35.

A protrusion 7a provided as a rising portion at one end of the clutch lever 7 engages with and disengages from the protrusion 30. That is,
When the lower edge 7b of the clutch lever 7 is restricted by the boss 31a of the support shaft 31, the projection 7a engages with the projection 30, and the clutch 7 is rotated counterclockwise by the bias of the spring 8. When it is moved, the protrusion 7a
It is adapted to be retracted to the inside to release the engagement.

A pin 38 embedded in the lens barrel 36 is pressed against the cam surface 28 of the focus adjustment ring 5. The lens barrel 36 carries a taking lens 39 and is biased rearward by a spring 40. Note that the lens barrel 36 is moved along the optical axis 42 without play by a conventionally known guide mechanism (not shown), and is not rotated around the optical axis 42.

The driving of the stepping motor 13 is controlled by a microcomputer 45, as shown in FIG. The microcomputer 45 includes a microprocessor unit 46 (hereinafter referred to as MPU 46), a program ROM 47 in which the driving sequence of the stepping motor 13 is stored, a table ROM 48 in which the rotation amount of the stepping motor 13 is stored, and a RAM 49. . The table ROM 48 is, as conceptually shown in FIGS. 3 and 4, a distance data ROM 48a to which a lens driving pulse number P _L is assigned corresponding to the object distance measured by the distance measuring device 50, and a luminance. The shutter pulse number P corresponding to the LV value detected by the detection circuit 51
It is composed of a luminance data ROM 48b to which _S is assigned. Further, the pulse counter 52 and the driver circuit 5
3 is used when the drive program stored in the program ROM 47 is executed by the MPU 46.

The operation of the above configuration is performed as follows. First, when the shutter release is performed and the release switch 55 is turned on, the brightness detection circuit 51 operates to detect the brightness of the subject, as shown in the flowchart of FIG. The MPU 46 refers to the luminance data ROM 48b based on this subject luminance information, and stores the shutter pulse number P _S corresponding to this subject luminance in a predetermined address of the RAM 49. Next, the distance measuring device 50 operates to detect the subject distance, and the distance data ROM 48a also stores the corresponding lens drive pulse number P _{L in the} RAM 49 at a predetermined address. For example, when the subject brightness is LV15 and the subject distance is 2.0 m, the shutter pulse number P _S
“3” and “23” as the lens driving pulse P _L are stored in the respective addresses of the RAM 49. When the pulse numbers P _S and P _L are thus determined, the pulse counter 52 is reset to “0”, and then the MPU 46 continuously outputs the normal rotation pulse to the driver circuit 53. Further, the number of this normal rotation pulse is counted by the pulse counter 52.

By supplying the normal rotation pulse to the driver circuit 53 in this way, the stepping motor 13 starts normal rotation at the timing T ₁ in the time chart of FIG. When the stepping motor 13 is rotated in the forward direction, the shutter drive ring 3 rotates counterclockwise from the position shown in FIG.
The clutch lever 7 itself also rotates with this. At this time, the projection 7a of the clutch lever 7 remains engaged with the projection 30 of the focus adjustment ring 5, so that the focus adjustment ring 5 is also driven by the shutter drive ring 3 to rotate counterclockwise. The clutch lever 7 is biased toward the inside of the protrusion 30 by the spring 8, but these are maintained in the engaged state as they are due to the engaging frictional force between the protrusion 7a and the protrusion 30.

In this way, as the shutter drive ring 3 rotates,
The pin 9 planted in the clutch lever 7 is the locking lever 32.
Since the lock is released, the locking lever 32 is swung by the spring 34, and the locking claw 33 comes into contact with the clutch teeth 29. Since the locking claw 33 and the clutch teeth 29 form a one-way clutch, the rotation of the focus adjusting ring 5 in the counterclockwise direction is continued. While the disk 17 is also rotated via the gear 18 during this period, the pin 19 does not come into engagement with the interlocking lever 20, so the shutter blade drive mechanism 25 is not operated.

By rotating the shutter drive ring 3 and the focus adjustment ring 5, the lens barrel 36 is gradually extended by the cam surface 28.
Although parallel with this increase also count value P _CT of the pulse counter 52, the count value P _CT lens driving pulse number P _L which is the memory in RAM _49, i.e., at the timing T ₂ that is equal to "23", The MPU 46 performs the processing shown in the flowchart of FIG. 8 according to the drive sequence of the program ROM 47. That is, MPU
46 outputs P _B reverse rotation pulses to the driver circuit 53, for example, 3 reverse rotation pulses, and as a result, the stepping motor 13 is rotated in reverse.

When the stepping motor 13 reverses in this way by three reverse pulses, the shutter drive ring 3 rotates in the opposite direction, so that the projection 7a of the clutch lever 7 is momentarily separated from the projection 30 of the focus adjustment ring 5. The number P _{B of the} reverse rotation pulses is set to the minimum number required to release the engagement between the protrusion 7a and the protrusion 30. When the engagement between the projection 7a and the projection 30 is released in this way, the focus adjusting ring 5 tries to return by the bias of the spring 35, but the engagement between the locking claw 33 and the clutch tooth 29 causes the focus adjusting ring 5 to return. 5 and the lens barrel 36 are positioned corresponding to the subject distance detected by the distance measuring device 50.

When the projection 7a of the clutch lever 7 is separated from the projection 30, the clutch lever 7 moves to the spring 8 as shown in FIG.
Is further oscillated in the counterclockwise direction about the shaft 6 and enters the inside of the protrusion 30. Then, from the timing T ₃ after the stepping motor 13 has a certain amount reversed, MPU 46 will be supplied a normal rotation pulse to the drive circuit 53, the stepping motor 13 rotates forward again. However, when the shutter drive ring 3 after the timing T ₃ rotates, since the clutch lever 7 is shifted to the disengaged position with respect to the focusing ring 5, only the shutter drive ring 3 times counterclockwise Move.

Then, the count value P _CT of the pulse counter 52, when the predetermined value P _0, which is the memory in the program ROM _47, the shutter drive ring 3 to the time T ₄ has been reached, for example, to "41" has rotated, the disc 17 planted The pin 19 provided rotates the interlocking lever 20. As a result, the operation of the shutter blade drive mechanism 25 is started, the shutter blade 48 is opened, and the exposure is started. The value of P ₀ “41” is set to a constant value that matches the timing when a pinhole is formed on the shutter blade 48.

After reaching the count value “41” of the pulse counter 52,
The value “3” of the shutter pulse number P _S stored in the RAM 49 is referred to, and the MPU 46 sets the pulse counter 52.
Supplying forward BALS to the drive circuit 53 until the count value P _CT of reaches "41 + P _S". Then, this count value P
At time T ₅ when _CT reaches “44”, the MPU 46 outputs a reverse rotation pulse to the driver circuit 53 as shown in the flowchart of FIG. As a result,
Since the shutter drive ring 3 rotates in the clockwise direction, the shutter drive pin 23 moves in the clockwise direction. When the shutter drive pin 23 is rotated clockwise, the shutter drive mechanism 25 operates the shutter blade 48 in the closing direction.

At the same time, the count value P _CT of the pulse counter 52 is decremented, and the shutter blade 48 is closed at time T ₆ when the value reaches “41”, and the exposure is completed. Since the reverse rotation pulse is continuously supplied to the driver circuit 53,
The count value P _CT of the pulse counter 52 is decremented, and the shutter drive ring 3 is further rotated clockwise. While the shutter drive ring 3 is returning in this way, the lower edge 7b of the clutch lever 7 contacts the boss 31a of the support shaft 31, and the clutch lever 7 is swung clockwise against the spring 8. Therefore, the pin 9 planted in the clutch lever 7 presses the upper edge 32 a of the locking lever 32. As a result, the locking lever 32 is swung clockwise against the spring 34, so that the locking claw 33 is separated from the clutch teeth 29. As a result, the focus adjustment ring 5 moves toward the spring 3
The urging force of 5 causes it to rotate and return clockwise.

In this point T _7, the count value P _CT is "0" in the pulse counter 52, since the clutch lever 7 is the lower edge 7b that is returned to contact with the initial position the support shaft 31, the projections of the focusing ring 5 The focus adjustment ring 5 is stopped at the initial position by the contact of 30 with the projection 7a of the clutch lever 7. The lens barrel 36 interlocked with this is also returned to the most retracted position. The number of lens drive pulses P _L
The maximum value of is determined within the range of the pulse number P ₀ or less until the shutter blade 48 becomes a pinhole.
Of course, the shutter pulse number P _S takes different values corresponding to the subject brightness, and accordingly the timings T ₄ to T _4
The exposure time determined in ₆ will change.

In the above-described embodiment, since the shutter drive ring 3 is driven by the stepping motor 13, the rotation amount of the motor can be accurately controlled based on the number of drive pulses supplied. When a servomotor or a DC motor is used instead of, a rotation amount detecting means such as a potentiometer is also used.
The signal obtained from this may be fed back to the motor driver circuit.

〔The invention's effect〕

As described above, according to the shutter drive device of the present invention, the shutter drive ring is driven by the motor controlled by the microcomputer in accordance with a series of sequence programs, and is driven by the shutter drive ring via the clutch mechanism. When the focus adjustment ring has rotated to a predetermined focus position, the process in the sequence program causes the motor to always rotate in the reverse direction by a certain amount, thereby releasing the clutch mechanism to move the focus adjustment ring to the focus position. I try not to turn over. In this way, by mechanically controlling the drive of the motor to perform the clutch mechanism release operation, the mechanical structure of the clutch mechanism is greatly simplified, and the clutch mechanism can be operated at optimal timing and with certainty. You will be able to release operation.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of essential parts showing an embodiment of the present invention. FIG. 2 is a functional block diagram of the present invention. FIG. 3 is a conceptual diagram of the distance data ROM used in the present invention. FIG. 4 is a conceptual diagram of the luminance data ROM used in the present invention. FIG. 5 is an explanatory diagram showing a state when the clutch lever moves to the release position. FIG. 6 is a time chart diagram for explaining the operation of the present invention. FIG. 7 is a flowchart showing a motor drive process until focus adjustment is performed. FIG. 8 is a flowchart showing a motor drive process until the shutter blades are opened. FIG. 9 is a flow chart showing the drive processing of the motor after the shutter blades are opened. 1 ... Shutter substrate 3 ... Shutter drive ring 5 ... Focus adjustment ring 7 ... Clutch lever 13 ... Stepping motor 23 ... Shutter drive pin 25 ... Shutter blade drive mechanism 29 ... Clutch teeth 30 ..Projection 31..support shaft 32..locking lever 33..locking claw 36..lens barrel

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03B 13/36

Claims (1)

[Claims] 1. A shutter drive ring driven by a motor for operating a shutter in response to photometric data, a focus adjustment ring for adjusting the extension position of a photographing lens, the shutter drive ring and a focus adjustment ring. In a camera provided with a clutch mechanism provided between the distance measuring device and a distance measuring device for detecting distance measuring data corresponding to the in-focus position, the number of lens drive pulses corresponding to the distance measuring data and the photometric data and The first storage means for storing the shutter drive pulse, the second storage means for storing a constant reverse rotation pulse number, and the respective pulse numbers are read from the first and second storage means and correspond to the lens drive pulse number. The motor in the forward direction, the motor is rotated in the reverse direction according to the reverse rotation pulse number, and then the reverse rotation pulse number and the shutter drive pulse. And a calculation means for setting a drive program for rotating the motor in the forward direction corresponding to the number of pulses obtained by adding the number and the drive program for rotating the motor in the reverse direction to the initial position. Rotation of the shutter drive ring during forward rotation according to the number of rotations, the focus adjustment ring is driven to rotate through the clutch mechanism, and the reverse rotation of the shutter drive ring occurs during reverse rotation of the motor corresponding to the number of reverse rotation pulses. Disengage the clutch mechanism to disconnect the shutter drive ring and the focus adjustment ring to position the focus adjustment ring, and the motor continues to the pulse number obtained by adding the reverse rotation pulse number and the shutter drive pulse number. Correspondingly, the shutter is opened by the forward rotation of the shutter drive ring during the forward rotation, and the shutter is released during the reverse rotation of the motor to the initial position. Performs shutter closing operation by the reverse rotation of the motor drive ring, a shutter drive device, characterized in that the clutch mechanism and the focusing ring was then returned to the initial position.