KR100809754B1 - Drive unit - Google Patents

Abstract

The driving device of the present invention is characterized in that the movable body can be prevented from being inclined when the movable body is stopped using the restraint. The drive device includes a piezoelectric element 24; A rod 25 provided at one end of the piezoelectric element; A movable body 30 frictionally interlocked with the rod; The drive pulse generating means 33, 34 for applying a drive signal to the piezoelectric element 24 is provided. The driving pulse generating means (33, 34) has a duty ratio other than 0.5 when the moving body 30 is moved, the piezoelectric element (Square wave driving signal for vibrating the rod 25 so as to cause a difference between the extension and contraction of the rod And a piezoelectric square wave driving signal for vibrating the rod 25 so that the movable body 30 does not substantially move while having a duty ratio of 0.5 when the movable body 30 makes contact with the regulating member 22. It is applied to the element 24.

Description

DRIVE UNIT

Figure 1a is an exploded perspective view of a conventional drive device,

1B is an assembly view of a conventional driving device,

2 is a view showing the vibration displacement of the rod of the drive device shown in FIG.

3 is a view for explaining a driving principle of the driving apparatus shown in FIG. 1;

4A is a view for explaining a method for detecting the origin of the moving object of the driving device shown in FIG. 1;

Figure 4b is a view showing a state in which the movable body of the drive device shown in FIG.

5A is an external configuration diagram illustrating a driving device according to an embodiment of the present invention;

5B is an enlarged view of the movable body illustrated in FIG. 5A;

6 is a view showing the configuration of a driving circuit and a control unit of the driving apparatus shown in FIG. 5A;

7 is a diagram showing a control signal applied to the driving circuit shown in FIG. 6 and a voltage applied to the piezoelectric element of the driving apparatus;

8 is a graph showing an example of the relationship between the duty ratio of the driving voltage and the relative moving speed of the moving body;

9 is a flowchart showing a process for detecting the origin of the drive device shown in FIG. 5A;

10A is a diagram showing a waveform of a driving voltage having a duty ratio of 0.3 as an example of the first waveform driving signal;

FIG. 10B illustrates waveforms of driving voltages having a duty ratio of 0.5 as an example of the second waveform driving signal.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a driving device for driving a moving body integrated with an optical component such as a lens used in a camera, a DVD drive, a CD drive, an MD drive, an endoscope, and the like.

A drive device using an electromechanical transducer such as a piezoelectric element that changes its dimensions (extension or contraction) when a voltage is applied, for example in an exploded perspective view shown in FIG. 1A and in FIG. 1B. Assembled perspective views are known (USP6, 016,231).

The piezoelectric element 4 comprises a plurality of stacked piezoelectric plates. One end 4a in the extension / contraction direction is fixed to the base 1, and the other end 4b is fixed to one end 5a of the rod 5 (support member). The rod 5 is slidably supported on the supports 2, 3 which are integrated with the base 1.

The rod 5 is held between the main unit 10a and the cap 10b of the moving body 10, and the pressing spring 10c is a pressing force against the main unit 10a and the cap 10b in the holding direction. Add. Thus, the movable body 10 is supported to slide along the rod 5.

The voltage control circuit is connected to the piezoelectric element 4. For example, when a predetermined driving voltage having a square wave or the like is applied to the piezoelectric element 4, the piezoelectric element 4 vibrates in accordance with displacement, and its shape is almost similar to the driving voltage. Because the rod 5 is flexible, the rod 5 vibrates in response to the displacement of the piezoelectric element 4 in accordance with the displacement having the sawtooth shape in the longitudinal direction thereof (see Fig. 2).

In particular, in the period A, the piezoelectric element 4 is stretched relatively slowly in the progressively rising inclined portion 101 of the first vibration displacement 100, so that the rod 5 is connected to the arrow I shown in Fig. 1B. It will move slowly in the direction indicated. Next, in the period B, the piezoelectric element 4 contracts rapidly and its length returns to the initial length (as shown by the waveform portion indicated by the falling slope 102). Thus, the rod 5 moves rapidly in the direction indicated by the arrow II.

Movement similar to the above is then repeated. As a result, the rod 5 repeats the slow movement in the direction I and the rapid movement in the direction II. Thus, the rod 5 vibrates in accordance with the displacement with the sawtooth oscillation wave characterized by a gradual rise and abrupt drop as shown in FIG.

As shown in Fig. 3, the spring force (the frictional connection force exerted from the movable body 10 to the rod 5) of the pressing spring 10c of the movable body 10 is adjusted, and the rod [in the period A] is loaded. The moving body 10 moves with the rod 5 when (5) moves slowly, and due to inertia (or more than the rod 5) when the rod 5 moves rapidly (in period B). Stayed where they move by a small amount. Thus, the movable body 10 moves relatively in the direction I with respect to the base 1 while the rod 5 vibrates.

When the movable body 10 is moved in the direction indicated by the arrow II shown in FIG. 1B, the vibration waveform of the rod 5 is represented by the waveform shown in FIG. 2, that is, having a sharp rise portion and a progressive drop portion. Can be reversed. The moving principle of the movable body 10 in this case is the same as the above-mentioned case. In this case, the vibration displacement of the rod can be reversed from that in FIG. 2 by changing the duty ratio of the square wave applied to the piezoelectric element 4.

The moving body 10 of the drive device can be moved relative to the base (fixed base) 1. Thus, the driving device can be used, for example, as a lens driving device of the camera. That is, according to the structure in which the movable body 10 is connected to the lens frame, the lens can be moved simultaneously with the movement of the movable body 10.

When a driving apparatus using a piezoelectric element having the above-described moving principle is used to move the optical member, position control of the moving body 10 becomes important. In the position control of the movable body 10, the position of the movable body 10 can be detected at all times, so that the movable body 10 can be stopped exactly at the position immediately before the end of the movable range. However, it is difficult to accurately perform position control for a drive device using such a piezoelectric element. Therefore, the support part 3 for supporting the rod is used as a restricting member for limiting the movement range of the movable body, and the movable body is in stable contact with the supporting member 3 for limiting the movement of the movable body (see FIG. 4A). .

However, when the movable body is brought into contact with the regulating member (support member 3) and stopped, if the driving of the piezoelectric element is not stopped immediately after the movable body makes contact with the regulating member, the movable body is inclined as shown in Fig. 4B. There is a problem. That is, when the driving device is actually used for lens barrels such as cameras, the diameter of the rod is about 1 mm, but the diameter of the lens frame 11 connected to the movable body is about 10 mm. Therefore, the size or weight of the member extending from the movable body is larger than that of the movable body. For this reason, if the movement of the movable body 10 is continuously restricted by using the restricting member 3 while the piezoelectric element 4 is driven to move the movable body 10, the movable body 10 is There is a tendency to slope. Although the tilt of the moving body is very small, when the driving device is connected to an optical member such as the lens 12, the tilt causes a serious deterioration in the performance of the optical system.

In order to solve this problem, the sensor can be made larger or the sensor which can accurately detect the position of the movable body can be prevented from tilting the movable body. However, such a configuration in which the regulating member is made larger or a sensor is provided is not desirable from the viewpoint of reducing the size of an optical system such as a lens barrel in recent years. Moreover, the provision of the sensor causes the problem of cost increase.

The present invention has been made in view of the above point, and an object thereof is to provide a driving device capable of preventing the inclination of the movable body when the movable body stops at a position in contact with the regulating member.

According to a first aspect of the present invention, there is provided a driving apparatus comprising: an electromechanical converter capable of stretching / contracting by applying a driving signal;

A support member connected to the electromechanical transducer and displaced with the electromechanical transducer;

A movable body that is slidably supported on the support member and moves along the support member due to vibration of the support member by extension / contraction of the electromechanical transducer;

A regulating member for regulating a movable range of the movable body;

A first waveform drive signal is applied to the electromechanical transducer for vibrating the support member so that a difference between the elongation and contraction of the support member is caused when the movable body moves to a position where the movable body is in contact with the regulating member, and the movable body is connected to the regulating member. And a driving circuit for applying a second waveform driving signal to the electromechanical transducer so as to vibrate the supporting member so that the moving body does not move after the contact is made.

In the above configuration, the second waveform driving signal may have a square wave having a duty ratio of 0.5.

In addition, the first waveform driving signal may have a square wave having a duty ratio other than 0.5.

Furthermore, the restricting member is provided at the reference position at which the position of the moving body of the drive device is detected.

Moreover, the movable body is pressed by the pressing force against the support member.

Further, the driving circuit is configured to apply the second waveform driving signal after the first waveform driving signal is applied for a predetermined time. In the above configuration, it is preferable that the predetermined time is a time sufficient to allow the movable body to reach the regulating member regardless of the position of the movable body in the movable range.

According to a second aspect of the present invention, there is provided a driving apparatus comprising: an electromechanical converter capable of stretching / contracting by applying a driving signal;

A support member fixed to one end of the electromechanical transducer in the extension / retraction direction;

A movable body slidably supported on the support member;

A pressing member for applying a pressing force to press the moving body toward the supporting member;

A regulating member provided to make contact with the movable body at one end of the movable range of the movable body;

Applying a first waveform drive signal to the electromechanical transducer for vibrating the support member such that when the movable body moves to a position where the movable body makes contact with the regulating member, the movable body moves relatively with respect to the supporting member against the pressing force, And a driving circuit for applying a second waveform driving signal to the electromechanical transducer so as to vibrate the supporting member so that the movable body does not move with respect to the supporting member after making contact with the regulating member.

In the above configuration, it is preferable that the first and second waveforms of the first and second waveform drive signals are square waves, and the first and second waveforms have different duty ratios. For example, the second waveform can have a duty ratio of 0.5.

In the above configuration, the restricting member slides the supporting member.

Moreover, the drive circuit applies a predetermined number of pulses as the first waveform drive signal to the electromechanical transducer.

According to the present invention, when the movable body is stopped at the position where it contacts with the restricting member, the inclination of the movable body due to the contact between the movable body and the restricting member can be corrected. That is, the inclination of the movable body caused when the movable body makes contact with the regulating member can be corrected by vibrating the supporting member, so that the movable body does not substantially move after the movable body makes contact with the regulating member. Thus, the movable body can be positioned without using a sensor or the like. Moreover, the displacement of the optical axis due to the displacement of the optical member provided in the movable body can be prevented.

Furthermore, by applying the square wave driving signal having a duty ratio of 0.5 as the second waveform driving signal, the movable body can cause a state in which the movable body does not move while the vibration of the electromechanical transducer is stably obtained. Therefore, the inclination of the movable body can be corrected without changing the position of the movable body.

Further, by applying a square wave driving signal having a duty ratio other than 0.5 as the first waveform driving signal, the movable body can be moved at a high speed in a predetermined direction.

Moreover, since the position of the movable body in contact with the regulating member is accurately detected, the position detection of the movable body can be easily performed using the position of the movable body as the reference position.

(Example)

Before proceeding with the description of the present invention, the same components are denoted by the same reference numerals. Hereinafter, a driving apparatus according to an embodiment of the present invention will be described in detail with reference to the exemplary drawings.

Figure 5a shows the configuration of a drive device according to an embodiment of the present invention. The driving device 20 according to the present embodiment is used to drive the lens frame 31 provided with the optical lens 32 used for the lens barrel of the camera.

The driving device 20 drives the moving body 30 based on the same principle as the driving device using the piezoelectric element 4 shown in FIG. The piezoelectric element 24 of the driving device 20 includes a multilayered piezoelectric plate. One end in the extension / retraction direction is fixed to the frame 21, and the other end is fixed to the end of the rod 25. The rod 25 is held between the main device 30a and the cap 30b of the movable body 30, and the pressing spring 30c exerts a pressing force against the main device 30a and the cap 30b in the holding direction. Thus, the movable body 30 is supported to slide along the rod 25.

For example, the rod 25 is held between the main device 30a of the movable body 30 and the cap 30b, and the pressing spring 30c is held in the holding direction to achieve frictional contact between the rod 25 and the movable body 30. The pressing force is applied to the main device 30a and the cap 30b. Thus, the movable body 30 is supported to slide along the rod 25. The lens frame 31 is fixed to the movable body 30 and moves simultaneously with the movement of the movable body. When the movable body 30 is inclined with respect to the rod 25, since the movable body 30 acts toward the rod 25 by the push spring, a force is applied to correct the inclination of the movable body 30.

The drive circuit 33 is connected to the piezoelectric element 24. Under control from the control unit 34, the driving circuit 33 applies a square wave driving voltage having a predetermined duty ratio to the piezoelectric element 24. That is, the controller 34 adjusts the position of the movable body 30 by controlling the driving circuit 33 to apply a square wave driving voltage having a predetermined duty ratio corresponding to the moving direction and the speed of the movable body 30.

As the piezoelectric element 24 is extended and contracted by the application of the driving signal, the movable body 30 moves along the rod. The movable range of the movable body 30 is between two supports 22 and 23. That is, the rod 25 is required to have a configuration whose length is longer than the movable range, and the size of the rod 25 is designed according to the movable range of the movable body 30. Moreover, the position where the movable body 30 makes contact with the support 22 is used as the origin for position control. That is, in the position control of the movable body 30, the origin used to detect the position of the movable body 30 can be detected by bringing the movable body 30 into contact with the support 22. According to the configuration in which the supports 22 and 23 are made sufficiently larger than the movable body, the movement of the movable body 30 can be restricted without causing the tilt of the movable body 30 during the origin detection which will be described later. However, in this embodiment, the supporting portion is made small, so that the driving device is made small in size.

A sensor 23a provided at one end of the movable range on the side of the support 23 detects that the movable body 30 makes contact with the support 23. The output of the sensor 23a is input to the control unit 34.

FIG. 6 shows an example of the configuration of the drive circuit 33 for applying a voltage to the piezoelectric element while being included in the drive device shown in FIG. 5A. In the drive circuit 33, four switches Q1 to Q4 and two capacitors C1 and C2 form an H-bridge circuit, so that the drive circuit 33 supplies a drive voltage to the piezoelectric element 24. Is authorized. The switches Q1 and Q2 are formed of P-channel MOSFETs, and the switches Q3 and Q4 are formed of N-channel MOSFETs.

The source of the switch Q1 is connected to the terminal Vp and the gate is connected to the terminal Sc1 of the control unit 34. The source of the switch Q2 is connected to the terminal Vp, and the gate is connected to the terminal Sc2 of the control section. The drain of the switch Q3 is connected to the drain of the switch Q1, and the source is grounded. In addition, the gate of the switch Q3 is connected to the terminal Sc3 of the control unit 34. The drain of the switch Q4 is connected to the drain of the switch Q2, and the source is grounded. Furthermore, the gate of the switch Q4 is connected to the terminal Sc4 of the control unit 34.

One terminal of the piezoelectric element 24 is connected to the drains of the switches Q1 and Q3, and the other terminal is connected to the drains of the switches Q2 and Q4. Furthermore, capacitors C1 and C2 are connected in parallel with switches Q3 and Q4, respectively, as shown in FIG. The capacitances of the capacitors C1 and C2 are the same as the capacitances of the piezoelectric elements 24. The control part 34 controls the voltage applied to the piezoelectric element 24 by switching the voltage input into the switches Q1-Q4. In particular, for example, when the voltage (high) is applied to the switches Q1 and Q3 and when there is no voltage (low) applied to the switches Q2 and Q4, the voltage -Vp is applied to the piezoelectric element. On the other hand, when there is no voltage (low) applied to the switches Q1 and Q3 and when the voltage (high) is applied to the switches Q2 and Q4, the voltage Vp is applied to the piezoelectric element 24.

As described above, the control unit 34 controls the voltage applied to the piezoelectric element 24 by turning on / off the voltage applied to the drains of the switches Q1 to Q4 as well as the piezoelectric medium via the driving circuit 33. A square wave driving voltage is input to the element 24. In particular, when the gate voltages of the switches Q1 to Q4 are controlled as shown in FIG. 7, the driving voltage applied to the piezoelectric element 24 has a square wave denoted as Load in FIG. As can be seen from FIG. 7, ta to td each represent a voltage application time period, and these time periods ta to td form one cycle.

First, in the period ta, the switches Q2 and Q4 go high, and the switches Q1 and Q3 go low. On the other hand, in the period tc, the switches Q2 and Q4 go low, and the switches Q1 and Q3 go high. Therefore, the voltage applied to the piezoelectric element 24 in the time period ta and the voltage applied to the piezoelectric element 24 in the time period tc have the same absolute value but the opposite signs.

In the time periods tb and td, since all the switches Q1 to Q4 go high, the voltage applied to the piezoelectric element 24 is zero. Therefore, when the cycles of ta to td are repeated, the square wave driving voltage shown in FIG. 7 is periodically applied to the piezoelectric element 24. During the time period tb, td, the changed shape of the piezoelectric element 24 returns to the original shape. Since the time periods tb, td are considerably shorter than the time periods ta, tc, the time periods tb, td can be set to zero. Only the ratio between the time periods ta and tc is adjusted to change the duty ratio of the driving voltage.

8 illustrates the relationship between the duty ratio and the moving speed of the moving body 30 as an example. As the duty ratio is increased from zero, the moving speed of the movable body 30 increases in the positive direction, and reaches a positive maximum value when the duty ratio is 0.3. Moreover, as the duty ratio exceeds 0.3, the speed becomes slower, reaching zero when the duty ratio is 0.5. At this time, the elongation and retraction speed of the rod 25 is the same, and the movable body has a margin for movement slightly. However, because the amounts of movement during stretching and contraction are the same, the movable body is in a state where the velocity thereof is relatively zero. In addition, as the duty ratio becomes larger than 0.5, the moving speed of the moving body increases in the negative direction, and reaches a negative maximum when the duty ratio is 0.7. Moreover, as the duty ratio exceeds 0.7, the negative speed gradually becomes slower, and the moving body stops when the duty ratio is 1.0. In this embodiment, the positive direction is the direction in which the movable body 30 moves toward the support 22, and the negative direction is the direction in which the movable body 30 moves toward the support 23.

Hereinafter, drive control of the drive apparatus according to the present embodiment will be described. As described above, the driving device moves the moving body 30 along the rod 25 in a desired direction by applying a square wave driving voltage having a predetermined duty ratio determined using the control unit 34. For the purpose of moving the movable body 30 at high speed, it is preferable that the duty ratio of the driving voltage is about 0.3 or 0.7 at this time. That is, when the duty ratio is 0.3, the movable body 30 moves at high speed toward the support 22, and when the duty ratio is 0.7, the movable body 30 moves at high speed toward the support 23.

When the movable body 30 moves to the end of its movable range, that is, when the movable body 30 is in contact with the supports 22 and 23, when the driving voltage is applied to the piezoelectric element 24, the movable body 30 is inclined. do. The drive device according to the present embodiment performs the following control to prevent or eliminate tilt.

When the movable body 30 makes contact with the end of the movable range on the front end side of the drive device, that is, the support 23, the sensor 23a performs position detection. That is, when the sensor 23a detects that the movable body 30 makes contact with the support 23, the application of the driving voltage to the piezoelectric element 24 is stopped. As a result, as the driving voltage is not applied when the movable body 30 is in contact with the support 23, the inclination of the movable body 30 is prevented.

On the other hand, when the movable body 30 makes contact with the end of the movable range on the element side of the drive device, that is, the support part 22, the following processing is performed. The limit position of the movable range, which is limited by using the support 22 as described above, is used as an origin for the position control of the movable body 30 and functions as a standby position of the movable body 30. That is, when the power supply of the camera integrated with the driving device is turned off or when the state of the camera is reset while the power is turned on, the movable body 30 is controlled to make contact with the support part 22 on the element side, and the origin Detection is performed.

9 is a flowchart showing the origin detection process for detecting the position of the moving object 30. In order to detect the origin of the moving object, the piezoelectric element 24 has a square waveform and a predetermined first waveform driving voltage having a duty ratio in the range of 0 to 0.5 to move the moving object 30 toward the element side. Is applied (step 1). 10A illustrates a waveform of a driving voltage having a duty ratio of 0.3 as an example of the first waveform driving signal. In the processing performed at this time, irrespective of the position of the movable body 30 on the rod 25, only a predetermined time stored in advance in the control unit 34 is applied to the piezoelectric element 24. The predetermined number of pulses is the number of pulses in which the amount of movement allowed for the movable body to come into contact with the support 22 can be stably obtained regardless of the position of the movable body 30 in the movable range. The specific value of this number is set in advance according to the length of the rod 25, the displacement of the piezoelectric element 24, and the like.

According to the position of the movable body 30, it is conceivable that the movable body 30 comes into contact with the support 22 before application of a predetermined number of pulses. However, the controller 34 applies a predetermined number of pulses regardless of whether or not the moving body 30 makes contact with the support 22. That is, the application of a predetermined number of pulses to the piezoelectric element 24 allows the movable body 30 to come into contact with the support 22 on the element side regardless of the position of the movable body 30 at the start of processing. (Step 3). Although the moving body 30 is in contact with the support 22, the piezoelectric element 24 may be driven by such an operation. In this case, the inclination of the movable body 30 is caused.

Next, after the application of the predetermined number of pulses is completed, the control section 34 changes the duty ratio of the driving voltage to 0.5 (step 4), and application of the predetermined number of pulses to the piezoelectric element is performed. According to this process, the piezoelectric element 24 can be vibrated without changing the position of the movable body 30, so that the inclination of the movable body 30 can be corrected by the pressing force applied to the movable body 30 (step 5). . FIG. 10B illustrates a waveform of a driving voltage having a duty ratio of 0.5 as an example of the second waveform driving signal.

As the number of pulses of the driving voltage having a duty ratio of 0.5 is set in step 4, values in the range of several to several tens can be selected as necessary according to the design of the driving apparatus. In this embodiment, it was confirmed that the inclination of the movable body 30 was corrected by applying 60 pulses.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, the above embodiment is configured such that a driving voltage having a duty ratio of 0.5 is applied when the position detection is performed only on the piezoelectric element side to move the movable body 30 with respect to the limit position of the movable range. Is calibrated. However, this process may be performed at both ends of the movable range. That is, the inclination of the movable body 30 caused by the contact by using this process instead of providing the sensor 23a can also be corrected in the support 23 on the tip side. In this case, it is preferable that the duty ratio of the first waveform driving voltage becomes greater than or equal to 1.0 and less than 1.0, and the duty ratio of the second waveform driving voltage becomes 0.5.

Furthermore, the control for bringing the movable body into contact with the support member and the control for correcting the tilt of the movable body in the above-described embodiment are performed by changing the number of pulses, but may also be performed by changing the application time of the driving voltage. .

Further, the second waveform driving voltage applied to correct the slope is not limited to the square wave voltage having a duty ratio of 0.5, but may be, for example, a voltage having a sine wave, a triangle wave, and a trapezoidal wave. In general, the drive voltage only needs to be a drive voltage having a waveform that can cause vibration so that the speed of the stretching and contraction of the electromechanical transducer is the same.

Moreover, the driving device is configured to move the lens used in the lens barrel of the camera, but the driving device is not limited to this configuration. For example, the driving device may be used as an actuator for driving a lens used in an MD drive, a CD drive, a DVD drive, or the like.

In addition, the support member is not limited to having a rod shape, and may have a plate shape, for example. Moreover, even when the movable body and the supporting member are moved relatively by suddenly moving the supporting member in the above-described embodiment, the mechanism removing the pressing force applied from the movable body to the supporting member is moved relative to the supporting member. Can be provided.

By properly combining the predetermined various embodiments described above, the effects of each embodiment can be produced.

In addition, this invention is not limited to the above-mentioned Example, Of course, it can change and implement variously within the range which does not deviate from the summary of this invention.

As described above, according to the driving device according to the present invention, the operation for detecting the origin of the moving body can be easily and stably performed without providing an auxiliary device such as a sensor. Moreover, the inclination of the movable body 30 caused when the movable body 30 comes into contact with the support 22 for the origin detection can be corrected by performing a simple process.

Claims (15)

An electromechanical transducer 24 capable of extension / contraction by applying a drive signal; A support member 25 connected to the electromechanical transducer 24 and displaced with the electromechanical transducer 24; A movable body (30) slidably supported on the support member (25) and moving along the support member (25) due to vibration of the support member (25) by extension / contraction of the electromechanical transducer (24); A regulating member (22, 23) for regulating the movable range of the movable body (30); Oscillating the support member such that a difference occurs between the extension and contraction of the support member 25 when the movable body 30 moves to a position where the movable body 30 makes contact with the restricting members 22 and 23. Applies the first waveform driving signal to the electromechanical transducer 24 and prevents the movable body 30 from moving after the movable body 30 makes contact with the regulating members 22 and 23. And a driving circuit (33) for applying a second waveform driving signal to the electromechanical transducer for vibrating the < RTI ID = 0.0 > The driving device as set forth in claim 1, wherein the second waveform driving signal is a square wave having a duty ratio of 0.5. The driving device according to claim 1, wherein the first waveform driving signal is a square wave having a duty ratio other than 0.5. 2. A drive device according to claim 1, wherein the restriction member (22, 23) is provided at a reference position at which the position of the movable body (30) of the drive device is detected. The driving device as set forth in claim 1, wherein said movable body (30) is pressed by a pressing force against said support member (25). 2. The driving device according to claim 1, wherein the driving circuit (33) applies the second waveform driving signal after the first waveform driving signal is applied for a predetermined time. 7. The method according to claim 6, wherein the predetermined time is a time sufficient to allow the movable body 30 to reach the regulating member 22, 23 regardless of the position of the movable body 30 in the movable range. Drive device characterized in that. An electromechanical transducer 24 capable of extension / contraction by applying a drive signal; A support member 25 fixed to one end of the electromechanical transducer 24 in an extension / retraction direction; A movable body (30) slidably supported on the support member (25); A pressing member (30c) for applying a pressing force to press the moving body (30) toward the support member (25); A regulating member (22, 23) provided to make contact with the movable body (30) at one end of the movable range of the movable body (30); When the movable body 30 moves to a position where the movable body 30 makes contact with the regulating members 22 and 23, the movable body 30 is relatively in relation to the supporting member 25 against the pressing force. A first waveform driving signal for vibrating the support member 25 to move is applied to the electromechanical transducer 24, and after the movable body 30 makes contact with the regulating members 22 and 23, the movable body And a drive circuit 33 for applying a second waveform drive signal for vibrating the support member 25 to the electromechanical transducer so that the 30 does not move relative to the support member 25. Drive system. 9. The driving device according to claim 8, wherein the first and second waveforms of the first and second waveform driving signals are square waves. 10. The driving device according to claim 9, wherein the first and second waveforms of the first and second waveform drive signals have different duty ratios. 11. A drive device according to claim 10, wherein said second waveform has a duty ratio of 0.5. 9. The driving device according to claim 8, wherein the regulating member (22, 23) supports the support member (25) in a slippery manner. 9. A drive device according to claim 8, wherein said drive circuit (33) applies a predetermined number of pulses as said first waveform drive signal to said electromechanical transducer (24). 9. A drive device according to claim 8, wherein the support member has a rod shape. 15. The drive device according to claim 14, wherein the length of the support member is longer than the movable range of the movable body.

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