JP2016013009A - Driving method of vibrator, and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a vibration type actuator without disturbing drive of other devices even in the case where a drive frequency of the vibration type actuator becomes substantially equal to that of each of the other devices.SOLUTION: When driving a vibration type actuator 100 including a vibrator 12 including a piezoelectric element 3 and a rotor 7 to be driven by vibrations excited by the vibrator 12, a voltage to make the vibration type actuator 100 excite the vibrations having a frequency substantially equal to that of at least one harmonic component of the vibrations which are generated in the vibration type actuator 100 in the case where a drive voltage is applied to the piezoelectric element 3, and having a phase difference from the harmonic component within a range of 90° to 270° is applied to the piezoelectric element 3 while being superposed on the drive voltage, such that the vibration of the harmonic component is reduced to a dark noise level.

Description

  The present invention relates to a driving method of a vibrator used in a vibration type actuator that relatively moves a vibrator and a driven body using vibration excited by the vibrator, and an electronic device including the vibrator.

  The vibration type actuator is used, for example, for driving a photographic lens provided in the image pickup apparatus, and an annular type, a linear type, and a rod type are known. Among these, the rod-shaped vibration actuator includes a rod-shaped vibrator in which driving vibration is formed and a driven body (rotor) that is in pressure contact with the vibrator, and drives the vibrator and the driven body. It has a structure that is relatively moved by vibration (see, for example, Patent Document 1).

  The rod-shaped vibrator is composed of at least two elastic bodies and a piezoelectric element held between the two elastic bodies. The piezoelectric element has a predetermined clamping force (compressive stress) in order to increase driving efficiency. It has a structure that is tightened so that Then, an alternating voltage is applied to the piezoelectric element to cause the vibrator to excite two orthogonal bending vibrations, thereby generating an elliptical motion on the elastic body. In this way, the driven body is brought into pressure contact with the portion where the elliptical motion is generated on the elastic body, so that the driven body and the driven body are relatively moved using the frictional force between the elastic body and the driven body. A driving force (thrust) for movement can be generated.

  In the vibration type actuator, it is possible to generate a driving vibration having a large amplitude by applying an alternating voltage near the resonance frequency of the vibrator to the piezoelectric element. Further, the output of the vibration type actuator such as the number of rotations (rotation speed) and torque can be changed by controlling the frequency of the alternating voltage applied to the piezoelectric element. Therefore, the drive frequency of the vibration type actuator usually has a certain width.

JP 2002-291263 A

  For example, some imaging apparatuses equipped with a vibration type actuator for driving a photographing lens are equipped with a gyro sensor for detecting angular velocity for correcting camera shake during photographing. Here, the gyro sensor detects the angular velocity by measuring the vibration changed by the Coriolis force. Therefore, when the drive frequency of the vibration type actuator and the gyro sensor are substantially the same, the vibration of the vibration type actuator propagates through the imaging device and interferes with the gyro sensor, so that the gyro sensor detects an error signal and corrects camera shake. There is a risk of malfunction.

  Further, as described above, in addition to the range of drive frequencies of the vibration type actuators, there are variations in the drive frequency for each vibration type actuator and gyro sensor. Therefore, the frequency suitable for driving each of the vibration type actuator and the gyro sensor varies for each imaging device. In addition, in order to correct camera shake in a plurality of directions, an imaging device may include a plurality of gyro sensors having different driving frequencies. Furthermore, it has become clear that the vibration of the harmonic component of the vibration type actuator causes a decrease in the detection accuracy of the gyro sensor.

  As a method for dealing with these problems, a method is conceivable in which the drive frequency of the vibration actuator and its harmonics and the drive frequencies of the plurality of gyro sensors are set to different values that do not interfere with each other. However, when such a countermeasure is adopted, the structure of the vibrator of the vibration type actuator is greatly restricted, and a new problem such as an increase in the size of the imaging apparatus occurs.

  The present invention can drive the vibration type actuator without reducing the drive accuracy of the other device even when the drive frequency of the vibration type actuator and the other device such as the gyro sensor becomes substantially the same. An object is to provide a driving method.

  The vibrator driving method according to the present invention includes an elastic body and an electro-mechanical energy conversion element joined to the elastic body, and the electro-mechanical energy conversion element is supplied with a driving voltage that is an alternating voltage having a different phase. A vibrator driving method for generating a driving force on a contact surface of the elastic body with a driven body by applying the elastic body to the vibrator when the driving voltage is applied to the electromechanical energy conversion element. Superimposes a voltage that excites the vibrator with vibration having a frequency substantially the same as that of at least one harmonic component of the generated vibration and a phase difference with the harmonic component in the range of 90 ° to 270 °. A voltage is superimposed on the drive voltage and applied to the electro-mechanical energy conversion element.

  Another vibrator driving method according to the present invention includes an elastic body and an electro-mechanical energy conversion element joined to the elastic body, and the electro-mechanical energy conversion element is driven with an alternating voltage having a different phase. A vibrator driving method for generating a driving force on a contact surface of the elastic body with a driven body by applying a voltage, wherein the vibration is generated when the driving voltage is applied to the electromechanical energy conversion element. A voltage for reducing at least one harmonic component of vibration generated in the child to a background noise level is superimposed on the driving voltage as a superimposed voltage and applied to the electromechanical energy conversion element.

  An electronic apparatus according to the present invention includes an elastic body, a vibration type actuator including a vibrator having an electro-mechanical energy conversion element joined to the elastic body, a control unit that controls driving of the vibrator, and a predetermined unit. And an internal device that is driven at a frequency, wherein the control means includes at least one harmonic component of vibration generated in the vibrator when an AC voltage is applied to the electromechanical energy conversion element. When at least part of the frequency range overlaps with part of the drive frequency range of the internal device, the harmonic component and the frequency are substantially the same, and the phase difference between the harmonic component is 90 ° to A voltage within a range of 270 ° is superimposed on the AC voltage and applied to the electromechanical energy conversion element.

  According to the present invention, even when the drive frequency of the vibration type actuator and the other device such as the gyro sensor becomes substantially the same, the vibration type actuator is driven without reducing the drive accuracy of the other device. Can do. As a result, the design freedom of the vibrator used in the vibration type actuator can be increased, so that the vibration type actuator can be downsized and improved in performance, and thus the equipment on which the vibration type actuator is mounted can be downsized. And higher performance can be achieved.

It is sectional drawing which shows schematic structure of the vibration type actuator using the rod-shaped vibrator | oscillator which concerns on embodiment of this invention. FIG. 2 is a cross-sectional view of a vibrator constituting the vibration type actuator of FIG. 1 and a diagram schematically showing the magnitude of vibration amplitude of the vibrator. It is a figure which shows the relationship between the drive frequency and rotation speed of the vibration type actuator of FIG. 2 is an FFT spectrum representing vibrations of a vibrator when the vibration type actuator of FIG. 1 is driven by a conventional driving method and when driven by the driving method according to the first embodiment of the present invention. FIG. 2 is a block diagram of a driving circuit according to the first embodiment of the present invention for driving the vibration type actuator of FIG. 1. FIG. 4 is a block diagram of a drive circuit according to a second embodiment of the present invention for driving the vibration type actuator of FIG. 1. It is a perspective view which shows schematic structure of the digital camera carrying the vibration type actuator of FIG. It is a figure showing the relationship of each drive frequency of the vibration type actuator and gyro sensor in the digital camera of FIG.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a cross-sectional view showing a schematic structure of a vibration type actuator 100 using a rod-shaped vibrator according to an embodiment of the present invention. The vibration type actuator 100 is an object to be driven by the driving method described in the first to third embodiments described later.

  The vibration type actuator 100 includes a first elastic body 1, a second elastic body 2, a piezoelectric element (electro-mechanical energy conversion element) 3, a shaft 4, and a lower nut 5, which are rod-shaped vibrators 12 (as appropriate). , See FIG. 2 described later). The vibration type actuator 100 includes a sliding member 6, a rotor (rotor) 7, a gear (output transmission member) 8, a pressure spring 9, a flange 10, and an upper nut 11. In the following description, the vibration type actuator 100 will be described with the lower nut 5 side as the lower side and the upper nut 11 side as the upper side as appropriate.

  The piezoelectric element 3 is sandwiched between the first elastic body 1 and the second elastic body 2, and is joined to the first elastic body 1 and the second elastic body 2 with an adhesive or the like. And the lower nut 5 is tightened so that a predetermined clamping force (compression force) is applied. The piezoelectric element 3 has a laminated structure in which piezoelectric material layers and electrode layers are alternately stacked. The electrode layer includes a drive electrode layer in which two electrodes are formed and a common electrode layer in which one electrode is formed. Are arranged for each layer, and two pairs of electrodes are formed. When alternating voltages having different phases are applied to two pairs of electrodes from a power source (not shown), two bending vibrations orthogonal to the vibrator 12 are excited as described later with reference to FIG.

  The flange 10 is a member for attaching the vibration type actuator 100 to an external member (not shown) such as a frame of a device on which the vibration type actuator 100 is mounted, and is fixed to a predetermined position in the thrust direction of the shaft 4 by the upper nut 11. ing. A flange cap 10 a is press-fitted into the lower convex portion of the flange 10.

  The lower end surface of the sliding member 6 is in contact with the upper surface of the first elastic body 1. The sliding member 6 has a small contact area and an appropriate spring property. The rotor 7 is fixed to the sliding member 6. The gear 8 is disposed on the upper side of the rotor 7, and a concave portion provided on the upper side of the rotor 7 and a convex portion provided on the lower side of the gear 8 are engaged. The pressure spring 9 is disposed between the rotor 7 and the gear 8. Due to the spring force of the pressure spring 9, the gear 8 is pressed against the flange cap 10a to determine the position in the thrust direction, and pressurizes the rotor 7 downward. As a result, the lower end surface of the sliding member 6 fixed to the rotor 7 is pressed against the upper surface of the first elastic body 1 and brought into pressure contact, whereby a predetermined frictional force is generated on the contact surface. As will be described later, the sliding member 6, the rotor 7, the gear 8, and the pressure spring 9 rotate together around the shaft 4.

  2A is a cross-sectional view of the vibrator 12, and FIG. 2B is a diagram schematically showing the magnitude of vibration amplitude when the vibrator 12 is driven. FIG. 2B shows one of the two bending vibrations excited by the vibrator 12, and the other is not shown. The bending vibration not shown is in a direction perpendicular to the paper surface. Occur.

  By adjusting the phase of the AC voltage applied to the piezoelectric element 3 (AC electric field applied to the piezoelectric material layer), it is possible to give a 90 ° temporal phase difference between the two bending vibrations. The bending vibration of the vibrator 12 rotates about the axis of the shaft 4. As a result, an elliptical motion is formed on the contact surface that contacts the sliding member 6 in the first elastic body 1, so that a driving force is generated, and the sliding member 6 pressed by the first elastic body 1 is rubbed. Driven. Thus, the sliding member 6, the rotor 7, the gear 8, and the pressure spring 9 rotate together around the axis of the shaft 4. Therefore, the rotational output can be extracted from any of the sliding member 6, the rotor 7, and the gear 8 exposed to the outside, but generally the rotational output is extracted from the rotor 7. In addition, since the contact surface of the flange cap 10a and the gear 8 becomes a sliding surface, it is preferable that the friction coefficient of this sliding surface is small.

  FIG. 3 is a diagram showing a relationship between the drive frequency of the vibration type actuator 100 and the rotation speed of the rotor 7 (the number of rotations per unit time, that is, the rotation speed). As the drive frequency of the vibration type actuator 100 approaches the resonance frequency, the vibration of the frictional sliding surface with the sliding member 6 in the first elastic body 1 is expanded, so that the rotational speed of the rotor 7 increases. The vibration type actuator 100 is usually driven in a certain range near the resonance frequency in order to increase the number of rotations. However, it can be seen that the number of rotations can be controlled by changing the driving frequency. .

  FIG. 4A is an FFT (Fast Fourier Transform) spectrum of a signal obtained by measuring the vibration of the vibrator 12 being driven by the conventional driving method of the vibration type actuator 100 with a laser Doppler velocimeter. Since FFT is a known technique, description thereof will be omitted here.

  According to the conventional driving method of the vibration type actuator 100, since the harmonic voltage is included in the AC voltage used for driving, the harmonic wave also appears in the vibration of the vibrator 12. In addition to this, since the vibrator 12 repeats contact / non-contact with the sliding member 6, the vibration generated in the vibrator 12 is a harmonic component vibration of a natural number multiple of second order, third order, fourth order,. including. That is, the vibration of the vibrator 12 includes not only a component derived from an electric signal but also a harmonic component derived from mechanical contact, and even if the electric signal is an ideal sine wave, The wave component cannot be completely removed.

  In the present embodiment, a voltage for generating a vibration that cancels the vibration of the third harmonic of the harmonic components shown in FIG. Reduce the vibration of the third harmonic to the background noise level. Accordingly, it is possible to set the drive frequency of another device (for example, a gyro sensor of the imaging device) provided in the device on which the vibration type actuator 100 is mounted in the vicinity of a frequency that is three times the drive frequency range.

  Next, specific means for canceling the vibration of the third harmonic of the vibration type actuator 100 will be described. FIG. 5 is a block diagram of the drive circuit 150 for driving the vibration type actuator 100 according to the first embodiment of the present invention. The drive circuit 150 includes an oscillation circuit 101, a booster circuit 102, a speed detection circuit 103, a speed deviation calculation circuit 104, a PID calculation circuit 105, and a superimposed signal determination circuit 106. The drive circuit 150 operates under the control of a control unit (not shown) including a central processing unit (CPU), and the control unit and the drive circuit 150 constitute control means for the vibration type actuator 100. The control unit includes a ROM and a RAM. The ROM stores a program executed by the CPU, and the RAM temporarily stores various types of information. The CPU controls the operation of the drive circuit 150 by developing the program read from the ROM in the work area of the RAM. It should be noted that the functions of some of the circuits that constitute the drive circuit 150 (for example, the speed deviation calculation circuit 104, the PID calculation circuit 105, and the superimposed signal determination circuit 106) may be provided in the control unit.

  The oscillation circuit 101 generates a pulse signal obtained by adding a drive signal and a superimposition signal (described later) supplied from the superimposition signal determination circuit 106, and supplies the pulse signal to the booster circuit 102. Note that the oscillation circuit 101 supplies only the pulse signal of the drive signal to the booster circuit 102 until the superimposed signal is supplied from the superimposed signal determination circuit 106.

  The booster circuit 102 performs matching with the inductor included in the booster circuit 102 and the electrostatic capacitance of the piezoelectric element 3 constituting the vibration actuator 100, and applies the pulse signal supplied from the oscillation circuit 101 to a predetermined level (voltage). Value) and applied to the piezoelectric element 3. That is, the booster circuit 102 generates a superimposed drive voltage in which the drive voltage obtained by boosting the drive signal and the superimposed voltage obtained by boosting the superimposed signal are generated, and the generated superimposed drive voltage is applied to the piezoelectric element 3. . As a result, two orthogonal bending vibrations described with reference to FIG. 2 are excited in the vibrator 12 by the drive voltage of the superimposed drive voltage, and the rotor 7 is rotationally driven. As will be described later, the vibration excited in the vibration type actuator 100 by the superimposed voltage of the superimposed drive voltage has a role of canceling the amplitude of the third harmonic vibration excited in the vibration type actuator 100 by the drive voltage. Bear.

  The rotation of the rotor 7 in the vibration type actuator 100 is detected as an electrical signal by the encoder 120, and the detected electrical signal is supplied to the speed detection circuit 103. The speed detection circuit 103 converts the electrical signal supplied from the encoder 120 into a rotation speed (rotation speed) and supplies the converted signal to the speed deviation calculation circuit 104. The speed deviation calculation circuit 104 calculates a speed deviation that is a difference between the target rotation speed and the rotation speed supplied from the speed detection circuit 103, and supplies the calculated speed deviation to the PID calculation circuit 105.

  The PID calculation circuit 105 performs a calculation for performing well-known PID control based on the speed deviation supplied from the speed deviation calculation circuit 104, and determines a drive frequency that is an operation amount of the vibration type actuator 100. The drive frequency thus determined by the PID arithmetic circuit 105 is supplied to the oscillation circuit 101 as a drive voltage frequency command value and also supplied to the superimposed signal determination circuit 106.

  In the drive circuit 150, the phase difference between the superimposed voltage and the drive voltage and the amplitude of the superimposed voltage are determined based on the frequency and amplitude of the vibration of the third harmonic due to the drive voltage. Therefore, when the vibration actuator 100 is driven, the superimposed signal determination circuit 106 minimizes the amplitude of the vibration of the third harmonic derived from the mechanical contact or the electric signal for each frequency of the driving voltage. The phase and amplitude of the superimposed signal are stored.

  The superimposed signal determination circuit 106 determines the phase and amplitude of the superimposed signal based on the frequency information supplied from the PID arithmetic circuit 105 and supplies the determined signal to the oscillation circuit 101. The oscillation circuit 101 adds the above-described pulse signal based on the frequency, phase, and amplitude information of the drive signal supplied from the PID arithmetic circuit 105 and the superimposed signal supplied from the superimposed signal determination circuit 106. Is supplied to the booster circuit 102. As described above, the booster circuit 102 applies the superimposed drive voltage generated by boosting the pulse signal to the piezoelectric element 3.

  The phase difference of the vibration generated by the superimposed voltage of the superimposed drive voltage with respect to the vibration of the third harmonic is preferably 90 ° to 270 °, and more preferably an opposite phase (180 °). The frequency of vibration due to the superimposed voltage and the frequency of vibration of the third harmonic cause the vibration amplitude of the third harmonic to interfere with the drive and operation of other devices provided in the device on which the vibration type actuator 100 is mounted. It need not be exactly the same as long as it can be offset to a lesser extent. That is, it is desirable that the frequency of vibration due to the superimposed voltage and the frequency of vibration of the third harmonic are the same, but it is not necessary to be completely the same, and the same frequency as long as the desired effect is obtained. As long as it is within a certain frequency range.

  The amplitude of vibration due to the superimposed voltage is preferably substantially the same as the amplitude of vibration of the third harmonic. Here, “substantially the same” means that the amplitude of the vibration of the third harmonic is canceled to such an extent that it does not interfere with the drive and operation of other devices provided in the device on which the vibration type actuator 100 is mounted. To the extent possible, it means that it is not necessary to be completely identical. Therefore, a certain range is allowed for the voltage value of the superposed voltage as long as vibration having substantially the same amplitude as that of the vibration of the third harmonic can be generated.

  FIG. 4B shows the vibrator 12 when the vibration type actuator 100 is driven by the superimposed drive voltage including the superimposed voltage for canceling the vibration of the third harmonic due to the drive voltage using the drive circuit 150 of FIG. It is an FFT spectrum showing the vibration of. As shown in FIG. 4B, it can be seen that the vibration of the third harmonic is reduced to the background noise level by using the driving method by the driving circuit 150 described above. As a result, it becomes possible to set the drive frequency of another device provided in the device on which the vibration type actuator 100 is mounted within the frequency range in which the vibration of the third harmonic has appeared in the prior art. It becomes possible to increase the degree of freedom. In the present embodiment, the case of canceling the vibration of the third harmonic has been described. However, the present invention is not limited to this, and it is needless to say that the vibration of other harmonics can be canceled by the same method.

Second Embodiment
FIG. 6 is a block diagram of a drive circuit 160 for driving the vibration type actuator 100 according to the second embodiment of the present invention. Among the circuits and the like constituting the drive circuit 160, the same parts as those of the drive circuit 150 described above are denoted by the same reference numerals and description thereof is omitted. Note that, similarly to the drive circuit 150, the drive circuit 160 also operates under the control of a control unit (not shown).

  In addition to the various circuits constituting the drive circuit 150, the drive circuit 160 detects a current flowing through the piezoelectric element 3 of the vibration type actuator 100, and a Fourier that performs FFT processing on the current detected by the current detection circuit 107. And a conversion device 108. From the calculation result by the Fourier transform device 108, the amplitude of the harmonic vibration to be reduced and the phase difference between the harmonic vibration and the fundamental vibration can be obtained. The calculation result in the Fourier transform device 108 is sent to the superimposed signal determination circuit 106.

  The superimposed signal determination circuit 106 determines the frequency, phase, and amplitude of the superimposed signal based on the drive signal supplied from the PID calculation circuit 105 and the calculation result supplied from the Fourier transform device 108. The oscillation circuit 101 generates a pulse signal by adding them based on the frequency, phase, and amplitude information of the drive signal and the superimposed signal supplied from the superimposed signal determination circuit 106, and generates the generated pulse signal. The voltage is supplied to the booster circuit 102.

  Thus, by feeding back the result of the FFT processing to the determination of the superimposed signal, the harmonic vibration can be reduced to the background noise level. In the present embodiment, the current flowing through the piezoelectric element 3 is measured. However, instead of the current, a part of the layer of the piezoelectric element 3 is used as a sensor layer, and a voltage generated in the sensor layer due to the positive piezoelectric effect. May be configured to perform FFT processing. This also makes it possible to detect the phase difference between the fundamental vibration and the harmonic vibration and the amplitude of the harmonic vibration.

<Third Embodiment>
In the third embodiment, an example in which the above-described vibration actuator 100 is mounted on an imaging device as an example of an electronic device will be described. FIG. 7 is a perspective view showing a schematic structure of a digital camera 200 which is an example of an imaging apparatus, and shows a partially transparent state.

  A lens barrel 202 is attached to the front surface of the digital camera 200, and a lens 209 and a camera shake correction optical system 203 are disposed inside the lens barrel 202. In FIG. 7, only one lens 209 is illustrated, but actually, a plurality of lens groups are arranged at predetermined positions in the lens barrel 202. The camera shake correction optical system 203 can vibrate in the vertical direction (Y direction) and the horizontal direction (X direction) by transmitting the rotation of the biaxial coreless motors 204 and 205.

  An image sensor 208 is disposed on the main body side of the digital camera 200, and light that has passed through the lens barrel 202 is formed on the image sensor 208 as an optical image. The image sensor 208 is a photoelectric conversion device such as a CMOS sensor or a CCD sensor, and converts an optical image into an analog electric signal. An analog electrical signal output from the image sensor 208 is converted into a digital signal by an A / D converter (not shown), and then subjected to predetermined image processing by an image processing circuit (not shown) to obtain image data (video data). It is stored in a storage medium such as a semiconductor memory (not shown).

  Further, on the main body side of the digital camera 200, as an internal device, a gyro sensor 206 that detects a shake amount (vibration) in the left-right direction (yawing) and a gyro sensor that detects a shake amount (vibration) in the vertical direction (pitching). 207 are arranged. The coreless motors 204 and 205 are driven in the direction opposite to the vibration detected by the gyro sensors 206 and 207 to vibrate the optical axis of the camera shake correction optical system 203. As a result, the vibration of the optical axis due to camera shake is canceled out, and a good photograph in which camera shake is corrected can be taken.

  The lens barrel 202 is provided with a lens group (not shown) that can move in the optical axis direction. The vibration type actuator 100 is driven by the driving method described in the first embodiment or the second embodiment, and drives a lens group disposed in the lens barrel 202 via a gear train (not shown). For example, the vibration type actuator 100 can be arbitrarily used for driving a zoom lens and / or driving a focus lens.

  FIG. 8 is a diagram illustrating the relationship between the drive frequencies of the vibration type actuator 100 and the gyro sensors 206 and 207. The drive frequency range of the vibration type actuator 100, its harmonics, and the drive frequency of the gyro sensor include individual variations. Here, a part of the drive frequency range of the yawing gyro sensor 206 and a part of the second harmonic frequency range of the drive frequency of the vibration type actuator 100 overlap. Further, a part of the driving frequency range of the pitching gyro sensor 207 overlaps with a part of the frequency range of the third harmonic of the driving frequency of the vibration type actuator 100. That is, a part of the driving frequency of the gyro sensor 206 and a part of the frequency range of the second harmonic vibration of the vibration type actuator 100 overlap, and a part of the driving frequency of the gyro sensor 207 and three parts of the vibration type actuator 100 are overlapped. A part of the frequency range of vibration of the second harmonic overlaps.

  However, by using the driving method described in the first and second embodiments, the vibration of the harmonic component of the vibration type actuator 100 can be reduced to a low noise level. Therefore, even when the lens barrel 202 is driven, the camera shake correction function can be realized by driving the gyro sensors 206 and 207 normally.

<Other embodiments>
Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. Furthermore, each embodiment mentioned above shows only one embodiment of this invention, and it is also possible to combine each embodiment suitably.

  In the present embodiment, the rod-shaped vibration type actuator has been described. However, the shape of the vibration type actuator is not particularly limited to this, and it may be an annular type or a plate type, and the driven body may be operated in a rotating manner. Regardless of direct acting type. Furthermore, the present invention can also be applied to piezoelectric devices other than the vibration type actuator, for example, a dust removing device used in a camera.

DESCRIPTION OF SYMBOLS 1 1st elastic body 2 2nd elastic body 3 Piezoelectric element 7 Rotor (rotor)
DESCRIPTION OF SYMBOLS 12 Vibrator 100 Vibrating type actuator 101 Oscillation circuit 102 Boosting circuit 103 Speed detection circuit 104 Speed deviation calculation circuit 105 PID calculation circuit 106 Superimposition signal determination circuit 107 Current detection circuit 108 Fourier transform apparatus 200 Digital camera 202 Lens barrel 206,207 Gyro Sensor

Claims (16)

An elastic body, and an electro-mechanical energy conversion element joined to the elastic body, and a drive body that is an alternating voltage having a different phase is applied to the electro-mechanical energy conversion element to drive the driven body in the elastic body A driving method of a vibrator for generating a driving force on a contact surface with
When the drive voltage is applied to the electromechanical energy conversion element, the frequency is substantially the same as that of at least one harmonic component of the vibration generated in the vibrator, and the phase difference between the harmonic component is 90. A method for driving a vibrator, characterized in that a voltage that excites the vibrator within a range of 270 ° to 270 ° is superimposed on the driving voltage as a superimposed voltage and applied to the electromechanical energy conversion element. An elastic body, and an electro-mechanical energy conversion element joined to the elastic body, and a drive body that is an alternating voltage having a different phase is applied to the electro-mechanical energy conversion element to drive the driven body in the elastic body A driving method of a vibrator for generating a driving force on a contact surface with
When the drive voltage is applied to the electromechanical energy conversion element, a voltage for reducing at least one harmonic component of vibration generated in the vibrator to a background noise level is superimposed on the drive voltage as a superimposed voltage. And applying to the electro-mechanical energy conversion element.   The vibration generated in the vibrator by the superimposed voltage has an opposite phase and substantially the same amplitude as the vibration of the at least one harmonic component generated in the vibration actuator by the drive voltage. 3. The vibrator driving method according to claim 1, wherein the vibrator is driven.   The phase difference of the superimposed voltage from the drive voltage and the amplitude of the superimposed voltage are determined based on the frequency and amplitude of vibration of the at least one harmonic component. The driving method of the vibrator according to any one of the above.   4. The amplitude and phase of the superimposed voltage are determined based on a current flowing through the electro-mechanical energy conversion element or a voltage generated by a positive piezoelectric effect in the electro-mechanical energy conversion element. The driving method of the vibrator according to any one of the above.   A frequency range for driving other devices included in a device in which a vibration type actuator having the vibrator and the driven body is mounted is included in a frequency range that is a natural number multiple of the frequency of the driving voltage. 6. The vibrator driving method according to claim 1, wherein the vibrator is driven.   When the frequency for driving another device provided in the device on which the vibration actuator is mounted is substantially the same as a frequency that is a natural number multiple of the frequency of the drive voltage, the superimposed voltage is The vibrator driving method according to claim 6, wherein the vibrator is applied to a mechanical energy conversion element. A vibration type actuator including an elastic body and a vibrator having an electro-mechanical energy conversion element joined to the elastic body;
Control means for controlling the drive of the vibrator;
An electronic device including an internal device that is driven at a predetermined frequency,
The control means is configured such that at least a part of a frequency range of at least one harmonic component of vibration generated in the vibrator when an AC voltage is applied to the electromechanical energy conversion element is within a drive frequency range of the internal device. In the case of overlapping with a part, a voltage whose frequency is substantially the same as that of the harmonic component and whose phase difference with the harmonic component is in a range of 90 ° to 270 ° is superimposed on the AC voltage. An electronic apparatus that is applied to the electro-mechanical energy conversion element.   The vibration generated in the vibrator by the superimposed voltage has an opposite phase and substantially the same amplitude as the vibration of the at least one harmonic component generated in the vibration actuator by the drive voltage. The electronic apparatus according to claim 8, characterized in that:   The phase difference between the superimposed voltage and the drive voltage and the amplitude of the superimposed voltage are determined based on the frequency and amplitude of vibration of the at least one harmonic component. The electronic device described.   The amplitude and phase of the superimposed voltage are determined based on a current flowing through the electromechanical energy conversion element or a voltage generated by a positive piezoelectric effect in the electromechanical energy conversion element. The electronic device as described in.   The frequency for driving another device provided in the electronic device is included in a frequency range that is a natural number multiple of the frequency of the driving voltage. The electronic device described.   The superimposed voltage is applied to the electromechanical energy conversion element when the frequency for driving another device provided in the electronic device is substantially the same as a frequency that is a natural number multiple of the frequency of the drive voltage. The electronic apparatus according to claim 12, wherein   The electronic apparatus according to claim 8, wherein the electronic apparatus is an imaging apparatus having an imaging element.   The electronic apparatus according to claim 14, wherein the internal device is a gyro sensor that detects a shake of the imaging device.   16. The electronic apparatus according to claim 14, further comprising a lens barrel in which a lens group that is movable in an optical axis direction by driving the vibration actuator is disposed.