JPH10160999A - Device and method for driving lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove backlash in a short time with low power consumption by reversing a lens barrel driving means by as much as the backlash without moving a lens barrel. SOLUTION: When a zoom lever is pushed to a WIDE side, the voltage level of a battery for supplying power to the lens barrel driving means is detected (step S1), and a reversing time in accordance with the voltage level is set (steps S2 to S4). While the zoom lever is pushed to the WIDE side, the lens barrel is driven in a WIDE direction by the lens barrel driving means (steps S5 to S7). When the zoom lever is released, the lens barrel driving means is actuated in a TELE direction for the set time but the lens barrel is not moved (step S8).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for driving a lens barrel in a camera or the like.

[0002]

2. Description of the Related Art Many cameras with a zoom lens have been developed and sold. In this camera, a lens barrel is driven in or out in response to a user operation of a zoom instructing unit (for example, a zoom lever). That is, when WIDE (wide-angle shooting) is instructed by the user through the zoom instructing means, the lens barrel is driven by the lens barrel driving means including a motor and a gear group, while TE is driven.
When LE (telephoto shooting) is instructed, the lens barrel is driven out by lens barrel driving means. However, the retraction drive is possible until the lens barrel reaches the WIDE end, which is the position where the lens barrel is most retracted and the wide-angle shooting is possible, and the extension drive is the most telescopic when the lens barrel is extended most. It is possible to reach the TELE end which is a position where photographing is possible.

[0003] Many cameras having a lens barrier in addition to a zoom lens have been developed and sold. In this camera, in the switch OFF state, the zoom lens is in a retracted state further retracted than the WIDE end, and the lens barrier is closed. When the switch is turned on, the zoom lens moves from the retracted position to the WIDE position.
The lens barrel is driven and extended to the end by the lens barrel driving means, and the lens barrier is opened, so that the wide-angle shooting is possible. When the switch is turned off, the zoom lens is driven and retracted by the lens barrel driving means to the retracted position, and the lens barrier is closed.

[0004]

The lens barrel driving means in the above-mentioned conventional camera with a zoom lens generally includes:
It is configured to include a motor and one or more gears that transmit the rotational drive of the motor to the lens barrel, and there is necessarily backlash. For example, if the lens barrel is driven in by the lens barrel driving means and driven by an external force while stopped at a certain position, the lens barrel moves in the retracting direction by the amount of backlash.

In a camera having a lens barrier, when the retracted position of the zoom lens and the WIDE end are close to each other, the lens barrel is driven in by the lens barrel driving means and then moved to the WIDE end. If the lens barrel is pushed by an external force while stopped at the end, the lens barrel moves in the retracting direction (retracting direction) by an amount corresponding to the backlash, and the lens barrier is thereby closed or half-opened, which hinders photographing. Will be.

In order to eliminate the backlash in which the lens barrel moves in the retraction direction due to such an external force, the lens barrel is driven by the lens barrel driving means based on the retraction instruction from the zoom instructing means. In addition, there is known a technique in which when there is no instruction from the zoom instructing means, the lens barrel is driven by a lens barrel driving means for a predetermined time (for example, Japanese Patent Application Laid-Open No. 62-265).
632). However, in this technique, since the lens barrel is actually driven out, the time required for this is about 500 ms, and the consumption of the battery that supplies power to the lens barrel driving means is expedited. Become.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a lens barrel driving apparatus and method capable of removing backlash in a short time with minimum power consumption. I do.

[0008]

A lens barrel driving device according to the present invention comprises: (1) zoom instructing means for instructing the retraction or extension of the lens barrel; and (2) an instruction from the zoom instructing means. Lens barrel driving means for driving the lens barrel in or out, and (3) retraction control means for causing the lens barrel driving means to drive the lens barrel in while the rewind instruction is issued by the zoom instructing means; (4) A feeding control means for operating the lens barrel driving means in the feeding direction by an amount substantially equal to the backlash in the lens barrel driving means after the end of the feeding instruction by the zoom instructing means.

According to this lens barrel driving device, while there is a retraction instruction by the zoom instructing means, the lens barrel driving means is controlled by the retraction control means to drive the lens barrel in. Thereafter, when the rewind instruction by the zoom instructing means is completed, the lens barrel driving means is controlled by the rewind control means and operates in the rewind direction by substantially the amount of backlash. At this time, the lens barrel does not move.

Further, in the lens barrel driving device, (5) voltage level detecting means for detecting a voltage level of a power supply for supplying power to the lens barrel driving means, and (6) voltage level detecting means. Operating time setting means for setting a time for operating the lens barrel driving means by the feeding control means based on the voltage level.

In this case, the voltage level detecting means detects the voltage level of the power supply for supplying power to the lens barrel driving means, and the operating time setting means controls the feeding control means based on the detected voltage level. The operation time of the lens barrel driving means is set. Therefore, even if the voltage level of the power supply fluctuates, the lens barrel does not move, and the lens barrel driving means operates in the extending direction substantially by the amount of backlash.

A lens barrel driving method according to the present invention is a lens barrel driving method in which a lens barrel is driven in or out by a lens barrel driving means based on a retraction instruction or a retraction instruction. ) A retraction control step of causing the lens barrel driving means to retract the lens barrel while the retraction instruction is given; and (2) after the retraction instruction is completed, the lens barrel is driven by approximately the backlash in the lens barrel driving means. And a delivery control step of operating the driving means in the delivery direction.

According to this lens barrel driving method, while there is a retraction instruction, the lens barrel driving means drives the lens barrel in the retraction control step. After that, when the retraction instruction is completed, the lens barrel driving means operates in the retraction direction by substantially the amount of backlash in the retraction control step. At this time, the lens barrel does not move.

Further, in the lens barrel driving device, the voltage is detected in (3) a voltage level detecting step of detecting a voltage level of a power supply for supplying power to the lens barrel driving means, and (4) a voltage level detecting step. Based on voltage level,
An operation time setting step of setting an operation time of the lens barrel driving means in the extension control step.

In this case, the voltage level of the power supply for supplying electric power to the lens barrel driving means is detected in the voltage level detecting step, and in the operation time setting step, based on the detected voltage level, the feeding control step is performed. The operation time of the lens barrel driving means is set. Therefore, even if the voltage level of the power supply fluctuates, the lens barrel does not move, and the lens barrel driving means operates in the extending direction substantially by the amount of backlash.

[0016]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

First, the lens barrel driving means and the lens barrel to which the present invention is applied will be described. FIG. 1 is an explanatory diagram of a lens barrel and lens barrel driving means. The lens barrel shown in this figure includes a fixed barrel 20, a rotating barrel 30, and a moving barrel 40. The lens barrel driving means includes a motor 10, a belt 11, and gears 12 to 1.
5 as well as the fixed cylinder 20, the rotating cylinder 30, and the moving cylinder 4
0 also includes a screw thread and a screw groove provided respectively. In this figure, for convenience of explanation, the fixed cylinder 2
0, a partial cross section or a partial cutaway view of the rotating cylinder 30 and the moving cylinder 40. The number of gears in the lens barrel driving means is arbitrary.
A gear group between the gear 2 and the gear 13 is omitted.

The fixed barrel 20 is fixed to the camera body 90, and the rotary barrel 30 and the movable barrel 40 are arranged concentrically in this order. The outer surface of the rotary cylinder 30 has a gear 30
A and a helicoid thread 30B are provided.
The gear 30 </ b> A meshes with the gear 15, and the helicoid thread 30 </ b> B meshes with a helicoid thread groove 20 </ b> B provided on the inner surface of the fixed cylinder 20 to form a helicoid mechanism.

A helicoid screw groove 3 is also provided on the inner surface of the rotary cylinder 30.
0C is provided, and a helicoid thread 40C is provided on the outer surface of the moving cylinder 40.
The thread 40C also meshes with each other to form a helicoid mechanism. Further, the movable barrel 40 slides along an axial straight guide (not shown) provided on the inner surface of the fixed barrel 20, and has a structure that does not rotate. A lens (not shown) is provided inside the moving cylinder 40.

In the thus constructed lens barrel and lens barrel driving means, the rotation of the motor 10 is carried out through the belt 11 and the gears 12 to 15 in order, and the screw thread 30 is rotated.
The rotation is transmitted to the rotating cylinder 30 via A, and the rotating cylinder 30 rotates. The rotating cylinder 30 is driven by a helicoid mechanism provided between the rotating cylinder 30 and the fixed cylinder 20 to be driven in or out in the axial direction while rotating. Further, when the rotating barrel 30 rotates, the rotating barrel 30 and the moving barrel 40 are rotated.
The moving cylinder 40 is driven in or out in the axial direction without rotating by the helicoid mechanism provided between the moving cylinder 40 and the rectilinear guide that prevents the rotation of the moving cylinder 40.

In this manner, both the rotary cylinder 30 and the movable cylinder 40 are driven in or out in accordance with the rotation direction of the motor 10, and this drive depends on the gears, threads and thread grooves. Therefore, a backlash is inevitably generated at each of the engagement between the gears, the engagement between the gears and the screw threads, and the engagement between the screw threads and the screw grooves. The present invention has been made to solve the problem caused by such backlash.

Next, the configuration of a control function in the lens barrel driving device according to the present invention will be described. FIG. 2 is a block diagram showing a configuration of a control function in the lens barrel driving device according to the present invention. In this figure, only the elements necessary for the control function in the lens barrel driving device according to the present invention are shown.

The CPU 1, which controls the operation of the entire camera,
A zoom lever (zoom instruction means) for inputting a user instruction relating to zooming (retracting / extending) of the lens barrel.
2. A voltage level detector 3 for detecting a voltage level of a battery for supplying electric power to the motor 10 and the like; a zoom position detector 4 for detecting a zoom position (retracting / extending position) of the lens barrel; Various types of control are performed between the motor control unit 5 that controls the stop, the ROM 6 that stores data necessary for control of the motor 10 and the like, and the timer 7 that is used to manage the time such as the rotation of the motor 10. Input and output signals.

Of these, the zoom lever 2 is provided on the outer surface of the camera body, and the zoom lever 2 is provided by the user in "WIDE".
Side (inward direction) or "TELE side (inward direction)", the CPU 1 is informed of this. Further, the motor control unit 5 responds to a control instruction issued from the CPU 1 based on an input from the zoom lever 2,
The motor 10 is operated in one of forward rotation, reverse rotation, and stop. That is, the zoom instruction input by the user via the zoom lever 2 is transmitted to the motor control unit 5 via the CPU 1.
The motor 10 is rotated based on the control of the motor control unit 5, and the lens barrel is driven in or out through the lens barrel driving means.

Further, ROM 6 stores in advance the value of the two data T _H and T _L. Data T _H, when the voltage level of the battery detected by the voltage level detection unit 3 is not less than the predetermined value, read out to the CPU 1, data T
_L is read by the CPU 1 in other cases. The timer 7 controls the motor control unit 5 to operate the motor 10 for a time T.
Used when rotating by _H or _TL . here,
Each of the data _TH and _TL is obtained by reversing the motor 10 in the extending direction after the lens barrel is driven in, when the voltage level of the battery is each,
This is the time required to remove the backlash without moving the lens barrel, and T _H <T _L.

Next, a lens barrel driving method according to the present invention will be described. FIG. 3 is a flowchart of the lens barrel driving method according to the present invention. This flowchart is
When the user pushes the zoom lever 2 to the WIDE side,
That effect is transmitted to the CPU 1 as an interrupt signal.
Zoom WIDE which is an interrupt process performed in PU1
It shows the flow of processing.

In this interrupt processing, first, in step S
In step 1, the voltage level detector 3 detects the voltage level of the battery that supplies power to the motor 10, and the CPU 1 receives the result. Subsequently, in step S2, the CPU 2
It is determined whether or not the detected battery voltage level is equal to or higher than a predetermined value. For example, if the battery is a nominal 3V lithium battery, it is determined whether the voltage level is 2.9V or higher. If it is determined that the voltage level is equal to or higher than 2.9 V, the process proceeds to step S3; otherwise, the process proceeds to step S4.

In step S3, the CPU 1 sets the ROM 6
Reads data T _H is set in the register from step S4, CPU 1 sets the register reads the data T _L from the ROM 6. That is, in each of step S3 and step S4, depending on the voltage level of the battery, the motor 10
Is set. Here, for example, T _H is 20
m seconds and T _L is 25 ms. When the processing in step S3 or step S4 is completed,
Go to 5. In step S5, the CPU 1 instructs the motor control unit 5 to energize the motor 10 so that the motor 10 rotates in the WIDE direction (retracting direction).
Start driving in the direction.

In step S6, the CPU 1 inputs the zoom position of the lens barrel detected by the zoom position detecting section 4 and determines whether or not the zoom position is at the WIDE end. If it is determined that it is the WIDE end, the process proceeds to step S8; otherwise, the process proceeds to step S7. In step S7, the CPU 1
It is determined whether or not the zoom lever 2 is still being pushed to the WIDE side. If it is determined that the zoom lever 2 is being pushed to the WIDE side, the process returns to step S6; otherwise, the process proceeds to step S8.

That is, as long as the zoom position has not yet reached the WIDE end and the zoom lever 2 is being continuously pushed to the WIDE side, the loop consisting of steps S6 and S7 is repeated, and the lens barrel is moved. , Continue to be driven. However, if the zoom position has already reached the WIDE end or the zoom lever 2 has not been pushed to the WIDE side, steps S6 and S7 are performed.
Then, the process proceeds to step S8.

In step S8, the CPU 1 instructs the motor control unit 5 to energize the motor 10 to rotate in the TELE direction (extending direction). However, the energizing time is T _H or T _L, which in step S3 or S4 is set to CPU1 registers are managed by the timer 7. During this energizing time, the TEL of the motor 10
The rotation in the direction E only removes the backlash of the lens barrel driving means and does not move the lens barrel.

When the backlash is removed in step S8 in this way, in step S9, the CPU 1
The motor control unit 5 is instructed to short-circuit the power supply terminals of the motor 10 with each other, and the motor brake is applied. This completes the zoom WIDE interrupt processing.

As described above, while the zoom position of the lens barrel has not yet reached the WIDE end and there is a retraction instruction from the zoom lever 2, steps S6 and S5 are performed.
In the loop consisting of 7, the lens barrel is controlled by the lens barrel driving means. Then, when the zoom position has already reached the WIDE end or when the retraction instruction from the zoom lever 2 ends, the lens barrel driving means is controlled to be extended by the amount of the backlash, but the lens barrel does not move. Absent.

Therefore, even if the lens barrel is driven in by the lens barrel driving means and driven by an external force in a state where it is stopped at a certain position, the lens barrel does not move in the retracting direction. Also, in a camera having a lens barrier, when the retracted position of the zoom lens and the WIDE end are close to each other, the lens barrel is driven in by the lens barrel driving means, and then the WIDE is moved.
Even if the lens barrier is pushed by an external force in a state where it is stopped at the end, the lens barrier does not enter the closed state or the half-open state. Furthermore, since the lens barrel is not moved when removing backlash, backlash can be removed in a short time with low power consumption.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, step S
In 2, the voltage level of the battery is determined in two stages, but may be determined in three or more stages, and the rotation time of the motor 10 in step S7 may be set according to each voltage level. . Further, the rotation time of the motor 10 in step S7 may be obtained by calculation based on the voltage level of the battery. Further, in step S7,
The removal of backlash without moving the lens barrel is performed by controlling the rotation time of the motor 10, but may be performed by controlling the rotation amount of the motor 10.

[0036]

As described in detail above, according to the present invention, the lens barrel driving means drives the lens barrel in while the rewinding instruction is given by the zoom instructing means (zoom lever). Is completed, the lens barrel driving means operates in the extending direction substantially by the amount of backlash, and at this time, the lens barrel does not move. Therefore, backlash can be eliminated in a short time with low power consumption.

Further, a voltage level of a power supply for supplying power to the lens barrel driving means is detected, and an operation time of the lens barrel driving means at the time of backlash elimination is set based on the detected voltage level. Thus, even if the voltage level of the power supply fluctuates, the lens barrel driving means operates in the extending direction substantially by the amount of the backlash to remove the backlash, but the lens barrel does not move.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a lens barrel and lens barrel driving means.

FIG. 2 is a block diagram showing a configuration of a control function in the lens barrel driving device according to the present invention.

FIG. 3 is a flowchart of a lens barrel driving method according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... CPU, 2 ... Zoom lever, 3 ... Voltage level detection part, 4 ... Zoom position detection part, 5 ... Motor control part, 6 ... R
OM, 7: timer, 10: motor, 11: belt, 1
2, 13, 14, 15: gear, 20: fixed cylinder, 30: rotating cylinder, 40: moving cylinder.

Claims (4)

[Claims] 1. A zoom lens instructing unit for instructing a retraction or extension of a lens barrel, a lens barrel driving unit for driving a retraction or extension of the lens barrel based on an instruction from the zoom instruction unit, While there is a retraction instruction by the zoom instructing means, retraction control means for causing the lens barrel driving means to perform retraction driving of the lens barrel, and after the retraction instruction by the zoom instructing means ends, the lens barrel driving means A lens barrel driving device, comprising: a feeding control means for operating the lens barrel driving means in the feeding direction by an amount substantially equal to the backlash. 2. A voltage level detecting means for detecting a voltage level of a power supply for supplying electric power to said lens barrel driving means, and said feeding control means based on the voltage level detected by said voltage level detecting means. The lens barrel driving device according to claim 1, further comprising: operation time setting means for setting an operation time of the lens barrel driving means. 3. A lens barrel driving method for driving a lens barrel in or out by a lens barrel driving means based on a retraction or extension instruction, wherein the lens barrel is driven while a retraction instruction is given. A retraction control step for causing the lens barrel to perform retraction driving of the lens barrel; and a dispensing control step for operating the lens barrel driving means in the retraction direction by substantially the amount of backlash in the lens barrel driving means after the retraction instruction is completed. A lens barrel driving method, comprising: 4. A voltage level detecting step for detecting a voltage level of a power supply for supplying electric power to the lens barrel driving means; and a step for controlling the feed-out based on the voltage level detected in the voltage level detecting step. The lens barrel driving method according to claim 3, further comprising: an operation time setting step of setting an operation time of the lens barrel driving means.