JP2009106152A - Controller of vibrating actuator, and optical instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the driving time of the driven member of a vibrating actuator is increased due to backlash of a power transmitting mechanism such as a decelerator, when driving it in the direction opposite to previous driving. <P>SOLUTION: In the driving device of a vibrating actuator, the frequency of the cyclic signal of the vibrating actuator is so set that the relation of f1<f3<f2 is satisfied among starting frequency f1, forward start frequency f2, reverse start frequency f3 of the vibrating actuator, thereby accurately controlling the vibrating actuator with reduced driving time and less overrun. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for a vibration type actuator, and further relates to an optical device such as a camera, an observation device, and a lens device using the vibration type actuator as a drive source.

  In a camera or a lens apparatus, a drive mechanism that drives a lens using a vibration type motor as a drive source may be employed. This vibration type motor has a vibration body by attaching an electro-mechanical energy conversion element to a metal elastic body, and applying a plurality of phase signals having different phases to the electro-mechanical energy conversion element. Vibration is excited, and the vibrating body and the contact body in pressure contact with the vibrating body (elastic body) are moved relative to each other to obtain a driving force.

  When driving a lens with such a vibration type motor, a method of controlling the driving speed of the lens by changing the frequency of the frequency signal input to the electromechanical energy conversion element has been put into practical use. In this method, the frequency of the frequency signal is often handled as a relative value because the driving speed obtained by each motor may be different.

  Therefore, every time the lens is driven, the frequency of the frequency signal when the lens starts to move is stored, and the frequency signal of the stored frequency is applied at the next motor start-up, so that the quicker start-up may be performed. .

  For example, in Japanese Patent Publication No. 5-038553, the frequency of the frequency signal at the start of relative driving of the movable body or object of the vibration type motor or a frequency within a predetermined range with respect to this frequency is stored. A technique of using this value as an initial value at the next startup of the vibration type motor is disclosed.

  FIG. 8 shows a schematic configuration of a focus lens driving system in a conventional lens device.

  In the figure, 210 is a microcomputer that controls the operation of the lens drive system, 201 is a VF converter that generates the frequency of a frequency signal for controlling the rotation speed (drive speed) of the vibration type motor 203, and 202 is a V-V converter. A drive circuit that generates a frequency signal having a frequency set by the F converter 201 and drives the vibration type motor 203, 204 is an encoder unit for detecting the drive amount and speed of the vibration type motor 203, and 205 is a vibration. A speed reducer 207 that decelerates the output of the mold motor 203 and transmits it to the focus lens unit 206, and 207 is an A / M switch for selecting whether the focusing operation is performed by autofocus or manual focus.

  FIG. 6 shows the relationship between the frequency of the frequency signal (drive signal) applied to the vibration type motor 203 and the motor rotation speed. In this figure, a range surrounded by a frame marked with 4 is a frequency region of a drive signal used for driving the lens unit 206.

  FIG. 7 shows the relationship between the drive signal frequency and drive speed of the vibration type motor 203 in the conventional lens drive system. The upper diagram in FIG. 7 shows how the driving speed of the vibration type motor 203 changes, and the lower diagram shows how the frequency of the frequency signal applied to the vibration type motor 203 changes.

  In FIG. 7, f <b> 1 is a motion start frequency representing a frequency when the vibration type motor 203 is activated during the previous drive, that is, a frequency at the time when the output of the encoder 204 is started. Further, f2 is a start-up frequency at the time of the current drive, and is set to the same frequency as the motion start frequency f1 at the previous drive or a predetermined frequency higher than the motion start frequency f1. Then, at the time of the current driving, the frequency of the driving signal is decreased from the starting frequency f2, and the motor 203 is accelerated.

Japanese Patent Publication No. 5-038553

  By the way, the speed reducer 205 is usually composed of several stages of gear trains or screws to reduce the rotational speed of the vibration type motor 203, so when driving the motor in the reverse direction with respect to the previous drive. The transmission of power to the lens unit 206 is delayed by the amount of backlash in the speed reducer 205. Although the backlash amount depends on the configuration of the speed reducer 205, the backlash amount ranges from 20 to 30 pulses at most in terms of the output pulse of the encoder 204.

  For this reason, at the time of reverse driving, it is necessary to drive the motor 203 by the amount corresponding to the backlash compared with the time of normal rotation (in the same direction as the previous driving). Therefore, as shown in FIG. 7, there is a problem in that the driving time becomes longer at the time of inversion than at the time of normal rotation even with the same driving amount.

  Therefore, the present invention can further reduce the drive time during the reverse drive when the drive output of the vibration type actuator is transmitted to the driven member (such as a lens) via a power transmission mechanism such as a speed reducer. It is an object of the present invention to provide a control device and an optical apparatus for a vibration type actuator.

In order to achieve the above object, according to the present invention, the vibration body and a contact body that contacts the vibration body using vibration excited by the vibration body by applying a frequency signal to the electromechanical energy conversion element, a vibratory actuator for generating a driving force by relative movement, has a backlash, the driving force of the vibration-type actuator comprising a drive having a power transmission mechanism for transmitting to the driven member, wherein the vibration In the type actuator, the frequency of the frequency signal is set in a frequency region higher than the resonance frequency of the vibration type actuator, the frequency of the frequency signal when the vibration type actuator starts to move by the frequency signal is f1, and the frequency of the vibration type actuator When the drive direction is the same as the previous drive direction, the current frequency signal is applied to the vibration type actuator. F2 is the starting frequency at the time of forward rotation, and f3 is the starting frequency at the time of reversal at the start of application of the current frequency signal to the vibration type actuator when the driving direction of the vibration type actuator is opposite to the previous driving direction. Then
f1 <f3 <f2
It is characterized by having a frequency setting means for setting each frequency so that

In the present invention, the vibration body and the contact body in contact with the vibration body are relatively moved by using the vibration excited by the vibration body by the application of the frequency signal to the electromechanical energy conversion element. An optical device having a vibration type actuator that generates a driving force by causing a vibration and a power transmission mechanism having a backlash and transmitting the driving force of the vibration type actuator to the optical element, wherein the vibration type actuator includes: The frequency of the frequency signal is set in a frequency region higher than the resonance frequency of the vibration type actuator, the frequency of the frequency signal when the vibration type actuator starts to move by the frequency signal is f1, and the driving direction of the vibration type actuator is When the frequency signal is applied to the vibration type actuator in the same direction as the previous driving direction, When the startup frequency f2, the driving direction of the vibration-type actuator and said inverted startup the frequency of the applied starting current frequency signals to the vibration type actuator f3 when it is opposite to the previous drive direction,
f1 <f3 <f2
It is characterized by having a frequency setting means for setting each frequency so that

  According to the present invention, when the drive output of the vibration type actuator is transmitted to a driven member (for example, an optical element) via a power transmission mechanism in which backlash exists, the drive direction of the vibration type actuator is the same as the previous drive direction. Even when it is the opposite (during reversal), the start of the driven member can be accelerated, the drive time can be shortened, and control with high accuracy with low possibility of overrun due to high speed start can be realized.

It is a block diagram which shows schematic structure of the camera system which is 1st Embodiment of this invention. It is a block diagram which shows schematic structure of the interchangeable lens apparatus which comprises the said camera system. It is a figure which shows the relationship between the frequency of the drive signal applied to a vibration type motor in the said lens apparatus, and the drive speed of a vibration type motor. It is a flowchart which shows control of the said vibration type motor. It is a flowchart which shows control of the vibration type motor in the lens apparatus which is 2nd Embodiment of this invention. It is the figure which showed the relationship between the frequency of the drive signal of a vibration type motor, and rotation speed. It is a figure which shows the relationship between the frequency of the drive signal applied to a vibration type motor in the conventional interchangeable lens, and the drive speed of a vibration type motor. It is a block diagram which shows schematic structure of the conventional interchangeable lens.

(First embodiment)
FIG. 1 shows a schematic configuration of a camera system according to the first embodiment of the present invention. This camera system includes a digital camera 106 having an image sensor 103 such as a CCD or CMOS sensor, and a lens device (optical apparatus) 105 that can be attached to and detached from the camera 106. Note that the camera system may be configured by using a film camera that takes an image on a photosensitive film instead of the image sensor 103.

  In the figure, reference numeral 101 denotes a focus lens drive unit using a vibration type motor as a drive source, and reference numeral 102 denotes a focus lens constituting a photographing optical system.

  FIG. 2 shows a schematic configuration in the lens device 105. In the figure, 10 is a microcomputer (frequency setting means) for controlling the operation of the lens drive system, and 1 is an electro-mechanical energy conversion element of the vibration type motor 3 for controlling the number of revolutions (drive speed) of the vibration type motor 3. V-F converter for setting the frequency of a frequency signal (in this embodiment, two-phase pulse signals having different phases; hereinafter referred to as drive signal), 2 is a frequency set by the V-F converter 1 Is a drive circuit that drives the vibration type motor 3, 4 is an encoder unit for detecting the drive of the vibration type motor 3, and 5 is an output that decelerates the output of the vibration type motor 3 to the focus lens 102. A transmission reducer 7 is an A / M switch for selecting whether the focusing operation is performed by autofocus or manual focus.

  FIG. 3 shows the relationship between the frequency of the drive signal of the vibration type motor 3 and the drive speed of the vibration type motor 3 in the focus lens drive mechanism using the vibration type motor 3 in the present embodiment.

  The upper diagram in FIG. 3 shows how the drive speed of the vibration type motor 3 changes, and the lower diagram shows how the frequency of the drive signal applied to the vibration type motor 3 changes.

  As shown in FIG. 6, the vibration motor 3 is driven by a drive signal in a frequency region (frequency region surrounded by a frame indicated by 4) higher than the resonance frequency at which the rotation speed reaches a peak. The vibration type motor 3 has a characteristic that the rotational speed increases as the frequency of the drive signal decreases.

  In FIG. 3, f <b> 1 is a movement start frequency representing a frequency when the vibration type motor 3 starts to move during the first driving after the lens device 105 is mounted on the camera 106, that is, when the output of the encoder 4 is started. Frequency.

  Further, f2 is the frequency of the drive signal applied to the vibration type motor 3 when the vibration type motor 3 is driven in the same direction as the previous drive (hereinafter referred to as forward rotation) at the time of the current start-up (hereinafter referred to as the positive direction). It is set to a frequency that is higher by a first predetermined frequency than the movement start frequency f1 during the first drive.

  Further, f3 is a frequency of a drive signal applied to the vibration type motor 3 (hereinafter referred to as inversion) when the vibration type motor 3 is driven in the opposite direction to the previous driving time (hereinafter referred to as inversion) at the time of this start-up. And is set to a frequency lower by a second predetermined frequency than the movement start frequency f1 during the first drive.

  In this manner, by setting the inversion start frequency f3 <starting frequency f1 <forward rotation start frequency f2, the vibration type motor 3 starts to move immediately upon the start of application of the drive signal during inversion.

  On the other hand, at the time of forward rotation, the vibration type motor 3 starts to move when the frequency is swept from f2 after the start of application of the drive signal and reaches the frequency f1. The normal rotation start frequency f2 is set to be somewhat higher than the movement start frequency f1 in this way. In normal rotation, for example, when driving one pulse, the drive must be stopped with one pulse as it is. This is because there is a possibility of overrun if the frequency starts to move below the frequency f1 and starts at a high speed from the beginning.

  On the other hand, since the backlash is added to the motor drive amount at the time of reversal, for example, even for one pulse drive, the backlash, for example, 20 pulses is added to it, and a total of 21 pulses of motor drive are required. Therefore, even if the start-up frequency is lowered and the start-up is started at a high speed, a known speed control is applied and no overrun occurs while the backlash is being driven.

  In this way, the time from when the vibration type motor 3 is started to when the focus lens 102 actually starts during reversal can be made shorter than when the forward rotation is started, so even if there is backlash in the speed reducer 5. The driving time required to drive the lens to the target position (target pulse) can be shortened to the same level as during normal rotation.

  FIG. 4 is a flowchart showing a control program for the vibration type motor 3 mainly executed by the microcomputer 10 in the present embodiment.

  First, in step [S401], the lens apparatus 105 is attached to the camera 106, and this flow starts.

  In step [S402], the microcomputer 10 performs initial settings such as setting of each port, reading of stored contents of an EEPROM (not shown), and initialization of a RAM.

  Next, in step [S403], the microcomputer 10 communicates with a microcomputer (not shown) in the camera 106 to determine whether or not a focus drive command has been received from the microcomputer on the camera side. If not received, the process waits as it is, and if received, the process proceeds to step [S404].

  In step [S404], the microcomputer 10 further receives data indicating the pulse drive amount (target position) and drive direction from the microcomputer on the camera side, and transfers the received data to the RAM in the microcomputer 10.

  At the time of reversal in which the driving direction is opposite to the previous driving time, data obtained by adding the number of pulses corresponding to the backlash of the speed reducer 5 to the pulse driving amount received from the camera 106 is transferred to the RAM. As the backlash amount, a design value is stored in advance in a ROM (not shown) in the microcomputer 10, or the backlash amount is measured and stored in an EEPROM (not shown) at the time of shipment from the factory.

  In step [S405], the microcomputer 10 determines whether or not the current driving of the vibration type motor 3 is the first driving. If it is the first drive, the process proceeds to step [S408], and if it is the second or later drive, the process proceeds to step [S406].

  In step [S406], the microcomputer 10 determines whether the driving direction received in step [S404] is normal rotation or reverse rotation. If normal rotation, the microcomputer 10 proceeds to step [S407]. If reverse rotation, the microcomputer 10 proceeds to step [S409]. move on.

  Here, a specific method for setting the frequency of the drive signal will be described. A frequency control RAM (not shown) in the microcomputer 10 is composed of 8 bits, and the frequency can be set in 256 steps from 00 hex to FF hex. 00hex is the highest frequency (low speed side), and FFhex is the lowest frequency (high speed side). When the motor 3 is accelerated or decelerated, the value of the frequency control RAM is changed.

  And when setting a starting frequency, it carries out as follows. First, in step [S407], the microcomputer 10 sets a starting frequency during normal rotation. Specifically, 10 hex (first predetermined frequency) is subtracted from the motion start frequency (8-bit data) stored in step [S413], which will be described later, and set in the frequency control RAM.

  In step [S409], the microcomputer 10 sets the activation frequency at the time of inversion. Specifically, 08 hex (second predetermined frequency) is added to the motion start frequency (8-bit data) stored in step [S413] described later, and the result is set in the frequency control RAM.

  In step [S408], the driving is the first time, and since the motion start frequency (8-bit data) f1 is not yet stored in step [S413] described later, the microcomputer 10 determines the starting frequency in advance. Set to maximum frequency and set to frequency control RAM.

  Next, in step [S410], driving of the vibration type motor 3 is started. Specifically, the microcomputer 10 sends the data set in the frequency control RAM in steps [S407] to [S409] to the D / A converter 10a to generate an analog signal. The analog signal sent from the D / A converter 10 a to the VF converter 1 is converted into a frequency by the VF converter 1, and a signal indicating the frequency is sent to the drive circuit 2. The drive circuit 2 generates a two-phase drive signal having a frequency and a phase different from each other in accordance with a signal from the VF converter 1, and inputs the drive signal to the electro-mechanical energy conversion element of the vibration type motor 3. .

  Here, in the case of normal rotation, the frequency of the drive signal is decreased from f2 at a predetermined reduction rate, and when the frequency reaches f1, the vibration type motor 3 starts to move. Then, as the frequency of the drive signal is lowered, the vibration type motor 3 is accelerated.

  On the other hand, in the case of inversion, the vibration type motor 3 starts moving immediately after the drive signal is applied, and the vibration type motor 3 is accelerated as the frequency of the drive signal is lowered from f3 at a predetermined rate of decrease. .

  When the rotational output of the vibration type motor 3 is input to the speed reducer 5, an output with an increased torque is obtained. Then, the focus lens 102 is driven by the output of the speed reducer 5. The encoder 4 attached to the motor 3 outputs a pulse signal when the output of the motor 3 is generated. This pulse signal is input to the microcomputer 10.

  In step [S411], the microcomputer 10 determines whether or not the first pulse is input from the encoder 4. If it is not input yet, the process waits as it is, and when the first pulse is input, the process proceeds to the next step [S412].

  In step [S412], the microcomputer 10 determines whether or not the current driving of the vibration type motor 3 is the first driving. If it is the first drive, the process proceeds to step [S413], and if it is the second or subsequent drive, the process proceeds to step [S414].

  In step [S413], the microcomputer 10 stores the data in the frequency control RAM at the time when the first pulse is input from the encoder 4 as the movement start frequency.

  Further, the microcomputer 10 takes the pulses input from the encoder 4 into the internal counter 10b and performs counting.

  At the same time, the internal timer 10c of the microcomputer 10 is operated to check whether the pulse interval matches the target pulse interval according to a predetermined algorithm (that is, the driving speed of the vibration type motor 3 follows the target speed pattern). Or not). If not, data is sent to the D / A converter 10a, and the frequency is changed so that the pulse interval input from the encoder 4 becomes the target pulse interval.

  In step [S414], the microcomputer 10 constantly monitors the data of the counter 10b and determines whether or not the pulse drive amount representing the target position sent from the camera 106 has been reached. Until the pulse drive amount sent from the camera 106 is reached, the speed is appropriately decelerated according to the remaining drive amount. When the pulse drive amount is reached, the data is immediately sent to the D / A converter 10a. In S415, the driving of the vibration type motor 3 is stopped.

  As described above, according to the present embodiment, when the driving direction at the start of the vibration type motor 3 is reversed with respect to the previous time, the starting frequency is lower than the forward rotation (lower than the movement start frequency). Therefore, by quickly starting the vibration type motor 3, the driving time of the focus lens 102 to the target position can be shortened to the same level as in the normal rotation even if there is a backlash in the speed reducer 5.

  In the present embodiment, the movement start frequency f1 is the frequency at which the vibration type motor 3 starts to move during the first drive after the lens apparatus 105 is mounted on the camera 106. However, the present invention is not limited to this. Good. For example, the movement start frequency at the time of normal rotation may be stored as f1, and the movement start frequency f1 may be updated every time forward rotation driving is performed.

In the present embodiment, the inversion start frequency f3 is set to be lower than the movement start frequency f1, but the present invention is not limited to this. For example,
Inversion start frequency f3 <Forward rotation start frequency f2
If the relationship satisfies the above, the inversion start frequency f3 may be set to a frequency higher than the movement start frequency f1.

(Second Embodiment)
FIG. 5 is a flowchart showing a control program for the vibration type motor of the lens apparatus according to the second embodiment of the present invention. The configurations of the lens apparatus and the camera to which the present embodiment is applied are the same as those of the lens apparatus and the camera of the first embodiment. In the description of the present embodiment, common components are the same as those of the first embodiment. The same reference numerals are given.

  First, in step [S501], the lens apparatus 105 is attached to the camera 106, and this flow starts.

  In step [S502], the microcomputer 10 performs initial settings such as setting of each port, reading of contents stored in an EEPROM (not shown), and initialization of a RAM.

  Next, in step [S503], the microcomputer 10 communicates with a microcomputer (not shown) in the camera 106 to determine whether or not a focus drive command has been received from the camera-side microcomputer. If not received, the process waits as it is. If received, the process proceeds to step [S504].

  In step [S504], the microcomputer 10 further receives data indicating the pulse drive amount (target position) and drive direction from the camera-side microcomputer, and transfers the received data to the RAM in the microcomputer 10.

  At the time of reversal in which the driving direction is opposite to the previous driving time, data obtained by adding the number of pulses corresponding to the backlash of the speed reducer 5 to the pulse driving amount received from the camera 106 is transferred to the RAM. As the backlash amount, a design value is stored in advance in a ROM (not shown) in the microcomputer 10, or the backlash amount is measured and stored in an EEPROM (not shown) at the time of shipment from the factory.

  In step [S505], the microcomputer 10 determines whether or not the current driving of the vibration type motor 3 is the first driving. If it is the first drive, the process proceeds to step [S511], and if it is the second or later drive, the process proceeds to step [S506].

  In step [S506], the microcomputer 10 determines whether the driving direction received in step [S504] is normal rotation or reverse rotation. If normal rotation, the microcomputer 10 proceeds to step [S507]. If reverse rotation, the microcomputer 10 proceeds to step [S508]. move on. A specific drive signal frequency setting method is the same as in the first embodiment.

  In step [S507], the microcomputer 10 sets the starting frequency for forward rotation. Specifically, 10 hex (first predetermined frequency) is subtracted from the motion start frequency (8-bit data) stored in step [S515] to be described later, and set in the frequency control RAM.

  In step [S508], the microcomputer 10 determines the amount of backlash in the speed reducer 5. For the backlash amount, the design value is stored in a ROM (not shown) in the microcomputer 10 or the backlash amount is measured at the time of shipment from the factory and stored in an EEPROM (not shown). If the backlash amount is less than 10 pulses converted to the output of the encoder 4, the process proceeds to step [S509], and if it is 10 pulses or more, the process proceeds to step [S510].

  In step [S509], the microcomputer 10 sets the activation frequency (inversion frequency 1) when the inversion is performed and the backlash amount is less than 10 pulses. Specifically, 04 hex (second predetermined frequency) is added to the motion start frequency (8-bit data) stored in step [S515] described later, and the result is set in the frequency control RAM.

  In step [S510], the microcomputer 10 sets an activation frequency (inversion activation frequency 2) when the inversion is performed and the backlash amount is 10 pulses or more. Specifically, 08 hex (second predetermined frequency) is added from the motion start frequency (8-bit data) stored in step [S515] to be described later, and set in the frequency control RAM.

  In these steps [S509] and [S510], at the time of inversion, the activation frequency is lowered as the backlash amount increases, and conversely, if the backlash amount is small, the activation frequency is not lowered too much. This is because if the backlash amount is large, the drive amount increases accordingly, so it is necessary to drive fast from the beginning in order to shorten the drive time. Conversely, if the backlash amount is small, driving fast from the beginning, especially during small drive This is because there is a possibility of overrun.

  In the present embodiment, the starting frequency is changed using 10 pulses as a threshold value.

  In step [S511], it is the first drive, and since the motion start frequency (8-bit data) f1 is not yet stored in step [S515], which will be described later, the microcomputer 10 sets the startup frequency to a predetermined maximum frequency. To the frequency control RAM.

  Next, in step [S512], driving of the vibration type motor 3 is started. Specifically, the microcomputer 10 sends the data set in the frequency control RAM in steps [S507] and [S509] to [S511] to the D / A converter 10a to generate an analog signal. The analog signal sent from the D / A converter 10 a to the VF converter 1 is converted into a frequency by the VF converter 1, and a signal indicating the frequency is sent to the drive circuit 2. The drive circuit 2 generates a two-phase or four-phase drive signal having the frequency and different phases according to the signal from the VF converter 1, and the electro-mechanical energy conversion element of the vibration motor 3. To enter. Thereby, the vibration type motor 3 is started.

  The encoder 4 attached to the vibration type motor 3 outputs a pulse signal when the output of the vibration type motor 3 is generated. This pulse signal is input to the microcomputer 10.

  When the rotational output of the vibration type motor 3 is input to the speed reducer 5, an output with an increased torque is obtained. Then, the focus lens 102 is driven by the output of the speed reducer 5.

  In step [S513], the microcomputer 10 determines whether or not the first pulse is input from the encoder 4. If it is not input yet, the process waits as it is, and when the first pulse is input, the process proceeds to the next step [S514].

  In step [S514], the microcomputer 10 determines whether or not the current driving of the vibration type motor 3 is the first driving. If it is the first drive, the process proceeds to step [S515], and if it is the second or subsequent drive, the process proceeds to step [S516].

  In step [S515], the microcomputer 10 stores the data in the frequency control RAM at the time when the first pulse is input from the encoder 4 as the movement start frequency.

  Further, the microcomputer 10 takes the pulses input from the encoder 4 into the internal counter 10b and performs counting.

  At the same time, the internal timer 10c of the microcomputer 10 is activated to determine whether or not the pulse interval matches the target pulse interval according to a predetermined algorithm (that is, the speed of the vibration motor 3 follows the target speed pattern). Whether or not). If not, data is sent to the D / A converter 10a, and the frequency is changed so that the pulse interval input from the encoder 4 becomes the target pulse interval.

  In step [S516], the microcomputer 10 constantly monitors the data of the counter 10b, and determines whether or not the pulse drive amount representing the target position sent from the camera 106 has been reached. Until the pulse drive amount sent from the camera 106 is reached, the speed is appropriately decelerated according to the remaining drive amount. When the pulse drive amount is reached, the data is immediately sent to the D / A converter 10a. In S517], the driving of the vibration type motor 3 is stopped.

  As described above, according to the present embodiment, when the driving direction at the start of the vibration type motor 3 is reversed with respect to the previous time, the starting frequency is lower than the forward rotation (lower than the movement start frequency). Therefore, by quickly starting the vibration type motor 3, the driving time of the focus lens 102 to the target position can be shortened to the same level as in the normal rotation even if there is a backlash in the speed reducer 5.

  In addition, in this embodiment, since the starting frequency at the time of inversion is changed according to the backlash amount, the occurrence of overrun at the time of small driving can be suppressed.

  In the first and second embodiments, the lens device that can be attached to and detached from the camera has been described. However, the present invention can also be applied to other optical devices such as a lens-integrated camera and an observation device. Further, the present invention can be applied not only to optical devices but also to various devices using a vibration type actuator as a drive source.

DESCRIPTION OF SYMBOLS 1 VF converter 2 Drive circuit 3 Vibration type motor 4 Encoder 5 Reducer 7 A / M switch 10 Microcomputer 102 Focus lens

Claims (2)

A vibration type that generates a driving force by relatively moving the vibrating body and a contact body in contact with the vibrating body using vibration excited by the vibrating body by applying a frequency signal to the electromechanical energy conversion element. An actuator,
A power transmission mechanism having a backlash and transmitting a driving force of the vibration type actuator to a driven member,
In the vibration type actuator, the frequency of the frequency signal is set in a frequency region higher than the resonance frequency of the vibration type actuator,
Application of the current frequency signal to the vibration type actuator when the frequency of the vibration type actuator is moved by the frequency signal is f1, and the drive direction of the vibration type actuator is the same as the previous drive direction. The starting frequency at the time of normal rotation at the start is f2, and the starting frequency at the time of inversion at the start of application of the current frequency signal to the vibration type actuator when the driving direction of the vibration type actuator is opposite to the previous driving direction is f3. Then,
f1 <f3 <f2
A drive device comprising frequency setting means for setting each frequency so that An optical element;
A vibration type that generates a driving force by relatively moving the vibrating body and a contact body in contact with the vibrating body using vibration excited by the vibrating body by applying a frequency signal to the electromechanical energy conversion element. An actuator,
A power transmission mechanism having a backlash and transmitting a driving force of the vibration type actuator to the optical element,
In the vibration type actuator, the frequency of the frequency signal is set in a frequency region higher than the resonance frequency of the vibration type actuator,
Application of the current frequency signal to the vibration type actuator when the frequency of the vibration type actuator is moved by the frequency signal is f1, and the drive direction of the vibration type actuator is the same as the previous drive direction. The starting frequency at the time of normal rotation at the start is f2, and the starting frequency at the time of inversion at the start of application of the current frequency signal to the vibration type actuator when the driving direction of the vibration type actuator is opposite to the previous driving direction is f3. Then,
f1 <f3 <f2
An optical apparatus comprising frequency setting means for setting each frequency so that

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