JP7379285B2 - Vibration drive devices, equipment, vibration actuator control devices - Google Patents

Description

The present invention relates to a vibration type drive device, an imaging device, a pan head device, an image forming device and equipment including the vibration type drive device, and a control device for a vibration type actuator that constitutes the vibration type drive device.

A vibration-type actuator is a non-electromagnetic actuator that is configured to bring a contact body into contact with a vibrating body and extract the vibration energy of high-frequency vibration generated in the vibrating body as mechanical motion that moves the contact body and the vibrating body relatively. It is a type actuator (motor). A vibrating body is generally constructed by bonding an electro-mechanical energy conversion element such as a piezoelectric element to an elastic body. The control device that controls the drive of the vibration type actuator includes a pulse signal generation circuit that generates a pulse signal, and a booster circuit that applies the AC voltage amplified by the transformer to the electro-mechanical energy conversion element.

The vibration type actuator can control the relative movement speed between the contact body and the vibrating body by adjusting the frequency, amplitude, and phase difference of the alternating current voltage applied to the electro-mechanical energy conversion element. Therefore, the vibration type actuator is used, for example, to drive a focus lens for performing an autofocus operation in an imaging device.

Autofocus operation requires highly accurate positioning control, and generally a focus lens is controlled to stop at a target stop position after accelerating, constant velocity, and deceleration using position feedback control using a position sensor. be done. In this case, it is desirable to suppress the power consumption in the control device and increase the driving efficiency of the focus lens. (resonant circuit) design is important. When using a booster circuit using a transformer, it is necessary to adjust the circuit constants according to the frequency range used for driving the vibration type actuator. Adjustment using circuit constants requires consideration of not only electric elements such as transformers, coils, and capacitors, but also the equivalent coil and equivalent capacitor of the mechanically vibrating portion of the vibrating body. On the other hand, for example, Patent Document 1 states that the parallel resonant frequency generated by the capacitance of the piezoelectric element and the output coil of the step-up transformer is the frequency at which the resonant frequency of the motor and the amplitude characteristics of the motor first reach their lowest level. A control device is described that is configured to be between.

Patent No. 2879220

The drive circuit described in Patent Document 1 can reduce the voltage fluctuation of the transformer output in a frequency range slightly higher than the resonance frequency. However, in terms of power consumption, only the reactive current of the vibration type actuator can be kept low, and a booster circuit that can achieve a greater effect of reducing power consumption is desired. Note that the reactive current refers to a current flowing through the capacitance of the electro-mechanical energy conversion element, and is a current component that does not contribute to vibration.

An object of the present invention is to provide a vibration type drive device that can reduce power consumption when driving a vibration type actuator.

A vibration type drive device according to the present invention is a vibration type drive device including a vibration type actuator and a control device that controls driving of the vibration type actuator, and the vibration type actuator includes an elastic body and an elastic body. A vibrating body having an electro-mechanical energy conversion element joined to the body, and a contact body in contact with the elastic body, and the control device applies an input signal to the electro-mechanical energy conversion element. It has a drive circuit having a transformer that converts it into an alternating current voltage, and a control unit that controls the frequency, phase, and voltage of the input signal, and sets the frequency at which the primary current of the transformer is minimum to f1, and It is characterized in that the following relationship is satisfied: 1.00≦f1/fa≦1.07, where fa is the frequency at which the next-side current becomes minimum.

According to the present invention, it is possible to reduce power consumption when driving a vibration type actuator.

FIG. 1 is a block diagram showing a schematic configuration of a vibration type drive device according to a first embodiment. 2 is a diagram illustrating a schematic configuration and vibration mode of a vibration type actuator that constitutes the vibration type drive device of FIG. 1. FIG. 2 is a circuit diagram of a drive circuit that constitutes the vibration type drive device of FIG. 1. FIG. 4 is a diagram illustrating a pulse signal output from a pulse signal generation circuit of the drive circuit of FIG. 3. FIG. 4 is a diagram illustrating frequency characteristics of the drive circuit of FIG. 3. FIG. 1 is a diagram showing the circuit configuration and characteristics of a booster circuit according to Example 1. FIG. FIG. 3 is a diagram showing the relationship between the value of f1/fa and the power ratio in a booster circuit. 3 is a diagram showing the circuit configuration and characteristics of a booster circuit according to Comparative Example 1. FIG. 7 is a diagram showing the circuit configuration and characteristics of a booster circuit according to Comparative Example 2. FIG. FIG. 3 is a diagram showing the relationship between driving speed and power consumption in an example and a comparative example. 7 is a diagram showing the circuit configuration and characteristics of a booster circuit according to Example 2. FIG. 3 is a diagram showing the circuit configuration and characteristics of a booster circuit according to Example 3. FIG. FIG. 2 is a perspective view showing a schematic structure of a lens drive mechanism. FIG. 7 is a diagram showing another configuration of the vibration type actuator. It is a figure which shows yet another structure of a vibration type actuator. It is a figure showing an example of the equipment provided with a vibration type drive device.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following explanation, "vibration type drive device" includes "vibration type actuator" and "control device", "vibration type actuator" includes "vibration body" and "contact body", and "vibration body" includes "elastic ``body'' and ``electrical-mechanical energy conversion element.'' Furthermore, when a vibration-type actuator is driven, the vibrating body and the contact body move relative to each other, but for the sake of explanation, it is assumed that the vibrating body is fixed at a predetermined position and does not move, and the contact body is movable relative to the vibrating body. do.

<First embodiment>
FIG. 1 is a block diagram showing a schematic configuration of a vibration type drive device 20 according to the first embodiment. The vibration type drive device 20 includes a vibration type actuator 23 and a control device 100 that controls driving of the vibration type actuator 23. The control device 100 includes a control section 110, a drive circuit 120, and a position sensor 24. The control section 110 includes a command section 111, a control calculation section 112, and a relative position detection section 113. The drive circuit 120 includes a pulse signal generation circuit 104 and a booster circuit 105. The vibration type actuator 23 has a vibrating body 1 and a contact body 2.

The position sensor 24 is, for example, an encoder, and detects the position of the contact body 2. The position sensor 24 is generally provided in the vibration actuator 23 as a hardware separate from the control unit 110 and the drive unit 220; 100.

The command section 111 generates a position command value for each time of the contact body 2 and sends it to the control calculation section 112 . The relative position detection unit 113 detects the position of the contact body 2 based on the output signal from the position sensor 24 and sends the detected position signal to the control calculation unit 112. The control calculation unit 112 calculates the positional deviation between the position command value input from the command unit 111 and the position signal input from the relative position detection unit 113, converts it into a control signal, and outputs the control signal to the drive circuit 120. Note that the control signal is a signal for generating alternating current voltages VA, VB (described later with reference to FIG. 2) to apply positional deviation to a piezoelectric element 204 (described later with reference to FIG. 2) constituting the vibrating body 1. This is converted into the phase difference, frequency, and pulse width, which are the control parameters of the pulse signal. The driving speed and driving direction of the contact body 2 are controlled based on the control variables of the phase difference, frequency, and pulse width output from the control unit 110. In this way, the control unit 110 performs position feedback control to control the drive of the vibration type actuator 23 based on the deviation between the position command value and the actual position of the contact body 2 at predetermined time intervals.

Note that the control calculation unit 112 may be, for example, a PID calculation unit, but is not limited thereto. Further, although the configuration here is such that position feedback control is performed, the present invention is not limited to this, and a configuration that performs speed feedback control based on speed deviation may be used. Furthermore, in view of the purpose of reducing power consumption when driving the vibration type actuator 23, a configuration may be adopted in which open drive control is performed without performing feedback control.

The pulse signal generation circuit 104 generates pulse signals having different phases (A-phase pulse signal, A-phase inverted pulse signal, B-phase pulse signal, and B-phase inverted pulse) based on control signals (control amounts of phase difference, frequency, and pulse width). (see FIG. 4)) and outputs it to the booster circuit 105. The booster circuit 105 generates two-phase alternating current voltages VA and VB with substantially sinusoidal waveforms and different phases by boosting an input signal generated by switching a DC power supply using an input pulse signal to a predetermined voltage using a transformer. generate.

When alternating current voltages VA and VB are applied to the piezoelectric element 204, vibrations, which will be described later, are generated in the vibrating body 1, and the contact body 2 moves in a predetermined direction due to the frictional driving force received from the vibrating body 1. The position of the contact body 2 is detected by the position sensor 24, and a detection signal is sent to the relative position detection section 113. In this way, as described above, position feedback control of the vibration type actuator 23 is performed so that the actual position of the contact body 2 follows the position command value every time.

FIG. 2 is a diagram illustrating a schematic configuration of the vibration type actuator 23 and vibration modes excited in the vibrating body 1. FIG. 2(a) is a perspective view showing a schematic configuration of the vibration type actuator 23. FIG. The vibrating body 1 constituting the vibration type actuator 23 has a substantially rectangular plate-shaped elastic body 203 and a substantially rectangular plate-shaped piezoelectric element 204 bonded to one surface of the elastic body 203 using an adhesive or the like. Projections 202 are provided at two locations on the other surface of the elastic body 203 (the surface opposite to the surface to which the piezoelectric element 204 is bonded).

FIG. 2(b) is a diagram showing an electrode pattern provided on the piezoelectric element 204. FIG. 2(c) is a diagram illustrating the first vibration mode excited in the vibrating body 1. FIG. 2(d) is a diagram illustrating the second vibration mode excited in the vibrating body 1. Note that the direction connecting the two protrusions 202 in the vibrating body 1 is defined as the X direction, the thickness direction of the elastic body 203 as the Z direction, and the direction orthogonal to the X direction and the Z direction as the Y direction.

On the surface of the piezoelectric element 204 opposite to the surface joined to the elastic body 203, two electrode regions are formed which are approximately divided into two in the longitudinal direction (X direction), and the piezoelectric material in each electrode region is formed. The polarization directions of are in the same direction (+). Although not shown, one electrode (common electrode) is provided on substantially the entire surface of the piezoelectric element 204 that is connected to the elastic body 203 .

Of the two electrode regions of the piezoelectric element 204 in FIG. 2(b), an AC voltage VB is applied to the right electrode region, and an AC voltage VA is applied to the left electrode region. When the AC voltages VA and VB have frequencies near the resonance frequency of the first vibration mode and are in the same phase, the piezoelectric element 204 as a whole expands at one moment and contracts at another moment. As a result, vibration in the first-order out-of-plane bending vibration mode occurs in the vibrating body 1, as shown in FIG. 2(c), in which two nodes appear in the vibrating body 1 substantially parallel to the X direction. Furthermore, when the AC voltages VA and VB have frequencies near the resonance frequency of the second vibration mode and the phases are shifted by 180 degrees, at a certain moment, one electrode area of the piezoelectric element 204 contracts and at the same time the other electrode area shrinks. The area stretches, and at other moments the opposite relationship occurs. As a result, vibration in the second-order out-of-plane bending vibration mode occurs in the vibrating body 1, as shown in FIG. 2(d), in which three nodes appear on the vibrating body 115 substantially parallel to the Y direction.

Here, the two protrusions 202 are arranged near a position that becomes an antinode of vibration in the first vibration mode and near a position that becomes a node of vibration in the second vibration mode. . Therefore, by exciting the first vibration mode and the second vibration mode simultaneously so that the vibration phase difference of the second vibration mode is around ±π/2 and superimposing them, the tip of the protrusion 202 can vibrate in the second vibration mode. It performs a pendulum motion using the node as a fulcrum and reciprocates in the X direction, and also reciprocates in the Z direction due to the vibration of the first vibration mode. This causes the tip surface of the protrusion 202 to undergo elliptical movement in the XZ plane, applying frictional driving force to the contact body 2 that is in contact with the tip surface of the protrusion 202, and moves the contact body 2 in the X direction. Can be driven. At this time, the driving speed of the contact body 2 can be adjusted by changing the phase difference between the AC voltages VA and VB.

Note that although a configuration in which the piezoelectric element 204 is driven with two-phase AC voltages VA and VB is taken up here, the control device 100 can also be used to drive and control a vibration-type actuator that is driven with three-phase or more AC voltages. Can be applied.

Next, the configuration of the drive circuit 120 will be explained in detail. The present invention focuses on the frequency at which the primary and secondary currents of the transformer are minimal, and in the drive circuit 120, circuit constants are set in accordance with the frequency range used for driving the vibration type actuator 23. That is, by adjusting the frequency characteristics of the current flowing through the booster circuit 105, the power consumption in the booster circuit 105 is reduced.

FIG. 3 is a circuit diagram of the drive circuit 120. Note that FIG. 3 only shows the circuit configuration that generates the AC voltage VA, and omits the illustration of the circuit configuration that generates the AC voltage VB. The circuit configuration that generates the AC voltage VB is the same as the circuit configuration that generates the AC voltage VA, so redundant explanation will be omitted.

The drive circuit 120 is roughly composed of a pulse signal generation circuit 104 and a booster circuit 105. The pulse signal generation circuit 104 includes an oscillator that generates a pulse signal, and a switching circuit (H bridge circuit) that switches the DC power supply using the pulse signal output from the oscillator, and an AC pulse signal Vi is output from the switching circuit. .

FIG. 4A is a timing chart of the pulse signal output from the oscillator of the pulse signal generation circuit 104. The oscillator generates an A-phase pulse signal (A+), which is 180 degrees out of phase with the A-phase pulse signal, based on a control signal having information on a phase difference, frequency, and pulse width input from the control unit 110. Outputs an inverted pulse signal (A-). A DC-DC converter circuit (not shown) that supplies DC power is connected to the switching circuit, and when the switching element is turned on and off by the pulse signal output from the oscillator, an AC pulse signal that is a rectangular wave AC voltage is generated. Vi is generated and output to the booster circuit 105.

Note that the pulse signal generation circuit 104 changes the pulse width (pulse duty) of the A-phase pulse signal and the A-phase inverted pulse signal by PWM (pulse width modulation) control so that an AC pulse signal Vi with a desired voltage amplitude is obtained. Adjust. The pulse width is set based on a control signal input from the control unit 110. Further, in this embodiment, a full-bridge drive switching circuit is used, but the present invention is not limited to this, and a half-bridge drive switching circuit or the like may be used.

The AC pulse signal Vi generated by the pulse signal generation circuit 104 is input to the boost circuit 105. The booster circuit 105 is composed of a coil 101 and a transformer 102 that form a resonance circuit with the electrostatic capacitance 106 of the piezoelectric element 204, and boosts the AC pulse signal Vi to a desired output voltage Vo to generate a substantially sinusoidal waveform. Generates an alternating current voltage VA. Note that the transformer 102 may have either polarity.

Note that the oscillator of the pulse signal generation circuit 104 generates a B-phase pulse signal (B+) based on a control signal having information on phase difference, frequency, and pulse width from the control unit 110. A phase-shifted B-phase inverted pulse signal (B-) is output (see FIG. 4(a)). AC voltage VB is generated in the same way as AC voltage VA is generated.

FIG. 4(b) is a timing chart illustrating the phase difference between the A-phase pulse signal and the B-phase pulse signal. Here, an example is shown in which the A-phase pulse signal and the B-phase pulse signal both have a duty of 50% and a phase difference of +90 degrees. Note that the period from time t0 to t4 is one cycle of the frequency for driving the vibration type actuator 23, and the rises of the A-phase pulse signal and the B-phase pulse signal are shifted by 1/4 cycle.

As shown in FIG. 3, the equivalent circuit of the piezoelectric element 204 is composed of an RLC series circuit of the mechanically vibrating portion of the vibrating body 1 and a capacitance Cd106 of the piezoelectric element 204 connected in parallel to the RLC series circuit. be done. The RLC series circuit is composed of an equivalent coil Lm107, an equivalent capacitor Cm108, and an equivalent resistor Rm109. The resonant frequency fm of the vibrating body 1 is determined by the equivalent coil Lm107 and the equivalent capacitor Cm108.

Although the equivalent resistance Rm109 varies depending on the load etc., it does not affect the resonance frequency fm. The electrical resonance frequency fe of the booster circuit 105 can be adjusted by the transformer 102, the coil 101, and the piezoelectric element 204. By adjusting the electrical resonance frequency fe, it is possible to reduce waveform distortion of the output AC voltage VA and to stabilize the voltage in the drive frequency range. In this embodiment, the electrical resonance frequency fe is adjusted mainly by changing the constant (inductance) of the coil 101.

The step-up transformer 102 has a primary coil 102a and a secondary coil 102b that are magnetically coupled. When a current flows through the primary coil 102a, magnetic flux is generated, and when a current flows inductively through the secondary coil 102b, a voltage is generated. In the transformer 102, the number of turns of the secondary coil 102b is set to be approximately several to 20 times that of the primary coil 102a, and the voltage amplitude on the primary side is amplified according to the ratio of the number of turns.

The current flowing through the primary coil 102a of the transformer 102 is an alternating current flowing from the power supply side of the pulse signal generating circuit 104 to the GND side through the coil 101 and the primary coil 102a via a switching element selected. Therefore, the power consumption on the primary side of the transformer 102 changes depending on the on-resistance of the switching element, the resistance components and current values of the coil 101 and the primary coil 102a. Because the primary current is generally larger than the secondary current due to the turn ratio in the transformer 102, power consumption also tends to increase. On the other hand, the current flowing to the secondary side of the transformer 102 is an alternating current flowing through the capacitance 106 of the piezoelectric element 204 and the mechanically vibrating portion (RLC series circuit) through the secondary coil 102b.

The frequency characteristics of the primary current and secondary current of the transformer 102 vary depending on the constants of the electric elements used in the booster circuit 105, the capacitance, and the equivalent constants of the mechanical vibration parts, but it is important to make the frequency characteristics the same or close to each other. Accordingly, the power consumption of the booster circuit 105 can be reduced.

The frequency characteristics of the drive circuit 120 will be explained with reference to FIG. 5. FIG. 5A is a diagram showing the relationship between the driving speed of the vibration-type actuator 23 (moving speed of the contact body 2) and the driving frequency when the vibration-type actuator 23 is driven.

As shown in FIG. 5A, with respect to the resonance frequency fm at which the maximum drive speed is obtained, the drive frequency range is from the minimum frequency fmin to the maximum frequency fmax on the higher frequency side than the resonance frequency fm. The reason why the minimum frequency fmin in the drive frequency range is set to a higher frequency side than the resonance frequency fm is to avoid the vibration type actuator 23 from becoming uncontrollable due to the drive frequency straddling the resonance frequency fm. .

If the starting frequency fd when starting the vibration-type actuator 23 is set near the maximum frequency fmax, there is a concern that the response will decrease.On the other hand, if the starting frequency fd is set near the minimum frequency fmin, the control There are concerns about the instability of Therefore, the starting frequency fd is set to a frequency that allows stable starting within the drive frequency range and takes control performance into consideration.

Further, the starting frequency fd needs to be set in consideration of the power consumption in the drive circuit 120. This is because the starting frequency fd makes it possible to reduce power consumption not only during starting but also during low-speed driving by controlling the phase difference or pulse width. In this embodiment, as described later, the frequency at which the primary current of the transformer 102 is minimum (hereinafter referred to as "minimum frequency f1") and the frequency at which the secondary current of the transformer 102 is minimum (hereinafter referred to as "anti-resonance frequency f1"), (referred to as "frequency fa") are matched or made close to each other by adjusting circuit constants. This reduces the power consumption of the drive circuit in the drive frequency range, and also sets the starting frequency fd between the anti-resonance frequency fa and the minimum frequency f1, effectively reducing power consumption during startup and low-speed driving. It becomes possible to do so. Note that the resonant frequency fm of the vibrating body 1 can be determined by the following equation 1, and it can be seen that the value depends on the equivalent coil Lm107 and the equivalent capacitor Cm108 of the mechanical vibration part of the vibrating body 1.

FIG. 5(b) is a diagram showing the relationship between the output voltage Vo from the booster circuit 105 and the drive frequency. An electrical resonance circuit is formed by the capacitance of the coil 101, the transformer 102, and the piezoelectric element 204, and the amplitude (voltage value) of the output voltage Vo shows a peak at the electrical resonance frequency fe. The electrical resonance frequency fe is generally set to a higher frequency side than the maximum frequency fmax, and by appropriately setting the electrical resonance frequency fe, it is possible to stably output an alternating current voltage with small waveform distortion.

The electrical resonance frequency fe of the booster circuit 105 is determined by each constant of the coil 101, the transformer 102, and the piezoelectric element 204, and can be determined by the following equation 2. Here, 'Le' is the inductance of the coil 101, 'L1' is the inductance of the primary coil of the transformer 102, 'L2' is the inductance of the secondary coil of the transformer 102, and 'M' is the mutual inductance of the transformer 102. Yes, it is expressed by the following formula 3. 'Cd' is the capacitance of the piezoelectric element 204.

In this embodiment, the coil 101 is provided on the primary side of the transformer 102 in the booster circuit 105, but the coil 101 is not limited to this, and may be provided on the secondary side, or may be connected in series with the transformer 102. However, they may be connected in parallel. Furthermore, a capacitor may be connected in series or in parallel to the primary or secondary side of the transformer 102. This is because the coil and capacitor are incorporated in the booster circuit 105 mainly for the purpose of adjusting the electrical resonance frequency fe and stabilizing the output voltage Vo. If the desired electrical resonance frequency fe and stable output voltage Vo can be obtained without a coil or capacitor, these are not necessarily necessary.

FIG. 5C is a diagram showing the relationship between the current flowing through the primary side and the secondary side of the transformer 102 of the booster circuit 105 and the drive frequency. The secondary current shown by the broken line in FIG. 5(c) has a peak at the resonance frequency fm and the electric resonance frequency fe. The anti-resonant frequency fa, which exhibits a minimum value between the resonant frequency fm and the electrical resonant frequency fe, can be determined by Equation 4 below. Here, 'Cd' is the capacitance of the piezoelectric element 204, and 'Lm' and 'Cm' are the equivalent coil and equivalent capacitor of the mechanically vibrating portion of the vibrating body 1, respectively.

The primary current shown by the solid line in FIG. 5(c) also has a peak at the resonant frequency fm and the electrical resonant frequency fe, like the secondary current, and a minimum frequency f1 exists between them. The relationship 'fa≦f1' exists between the minimum frequency f1 and the anti-resonance frequency fa, and these can be made closer or farther apart by adjusting the circuit constants. The minimum frequency f1 can be determined using Equation 5 below. Here, 'L2' is the inductance of the secondary coil of the transformer 102, 'Cd' is the capacitance of the piezoelectric element 204, 'Lm' and 'Cm' are the equivalent coil and the mechanically vibrating part of the vibrator 1, respectively. It is an equivalent capacitor.

In the present embodiment, the booster circuit 105 is designed such that the minimum frequency f1 of the primary current of the transformer 102 and the antiresonance frequency fa of the secondary current satisfy the relationship of Equation 6 below. By setting 'f1/fa', which is the ratio between the minimum frequency f1 and the anti-resonance frequency fa, near 1, that is, by making the minimum frequency f1 and the anti-resonance frequency fa coincide or close to each other, the Power consumption in booster circuit 105 can be reduced.

Desirably, a starting frequency fd is provided between the anti-resonant frequency fa and the minimum frequency f1. Specifically, as shown in Equation 7 below, the starting frequency fd is made to fall within 1% (approximately 1 kHz in frequency) of the boundary value defined by the anti-resonance frequency fa or more and the minimum frequency f1 or less. . This can enhance the effect of reducing power consumption when the vibration actuator 23 is activated or driven at low speed.

Further, it is desirable that both the anti-resonance frequency fa and the minimum frequency f1 be adjusted so that they fall within the drive frequency range (minimum frequency fmin or more, maximum frequency fmax or less) of the vibration type actuator 23, as shown by the following equation 8. This makes it possible to reduce power consumption in driving in a high-speed drive range at and around the minimum frequency fmin and in a low-speed drive range at and around the maximum frequency fmax.

Next, a specific design example of the booster circuit 105 will be described. FIG. 6A is a circuit diagram of a booster circuit 105A according to the first embodiment. Note that illustration of the overall configuration of the drive circuit 120 is omitted. The booster circuit 105A includes a coil 601 and a transformer 602 that correspond to the transformer 102 and coil 101 shown in FIG.

The AC pulse signal Vi is input to the boost circuit 105A, and the AC voltage Vo boosted by the transformer 602 is applied to the piezoelectric element 204. Regarding the inductance in the booster circuit 105A, the coil 601 has an inductance of 10 μH, the primary coil of the transformer 602 has an inductance of 47 μH, and the secondary coil has an inductance of 12 mH. Further, the capacitance Cd of the piezoelectric element 204 is 0.54 nF. The winding ratio of the transformer 602 is 16 times, the power supply is 3V, and an AC voltage Vo of about 120Vpp is output. The equivalent coil Lm of the mechanical vibration part of the vibrating body 1 is 50 mH, and the equivalent capacitor Cm is 65 pF. The resonant frequency fm of the vibrating body 1 is 88 kHz, and the electric resonant frequency fe is 142 kHz.

FIG. 6(b) is a diagram showing the results of simulating the relationship between the output voltage Vo of the booster circuit 105A, the primary current and secondary current of the transformer 602, and the drive frequency. By setting the booster circuit 105A to the circuit constants described above, the minimum frequency f1 at the primary current of the transformer 602 is 97 kHz, the antiresonance frequency fa at the secondary current of the transformer 602 is 93.5 kHz, and f1/ fa=1.04, which satisfies the relationship of Equation 6 above. At this time, the primary current of the transformer 602 at the anti-resonant frequency fa (=93.5 kHz) is 0.23 A, and the circuit power consumption is 71 mW (the power ratio in FIG. 7 described later is about 1.75). In the case of the control device 100 having the booster circuit 105A of the first embodiment, the minimum frequency fmin is set to 89 kHz and the maximum frequency fmax is set to 98 kHz in the drive frequency range. Further, the starting frequency fd is set in the range of 92.6 to 98.0 kHz.

FIG. 7 is a diagram showing the results of simulating the power ratio when the ratio (f1/fa) between the minimum frequency f1 and the anti-resonant frequency fa is changed in the configuration of the booster circuit 105A. Note that FIG. 7 shows similar simulation results for the configuration of each booster circuit according to Examples 2 and 3, which will be described later, and characteristics of Comparative Examples 1 and 2, which will be described later. Also, the power ratio is the power consumption when the value of f1/fa is adjusted in the range of 1.00 to 1.20, based on 'f1/fa = 1.01', which is the condition for the lowest power consumption. is calculated as a relative ratio. The power consumption is the total value of the power consumed by the circuit elements due to the primary current and secondary current of the transformer 602 when the starting frequency fd is set to the anti-resonance frequency fa.

The effect of reducing the power consumption in the booster circuit can be obtained when the value of f1/fa satisfies the relationship of equation 6 above, but the condition for the lowest power consumption is 'f1/fa=1. This is a case where the relationship 01' is satisfied. As f1/fa approaches 1 from 1.01, the power ratio increases. This is because the inductance of the coil of the transformer 602 increases, and as the inductance increases, loss due to resistance components increases. In the booster circuit 105A according to Example 1, f1/fa=1.04, and it is possible to reduce power consumption compared to Comparative Examples 1 and 2, which will be described later.

FIG. 8A is a circuit diagram of a booster circuit 800A according to Comparative Example 1. The AC pulse signal Vi is input to the boost circuit 800A, and the AC voltage Vo boosted by the transformer 802 is applied to the piezoelectric element 204. Regarding the inductance of the booster circuit 800A, the coil 801 has an inductance of 12 μH, the primary coil of the transformer 802 has an inductance of 30 μH, and the secondary coil has an inductance of 7.68 mH. Further, the capacitance Cd of the piezoelectric element 204 is 0.54 nF. The transformer 802 has a winding ratio of 16 times, a power supply of 3V, and outputs an AC voltage Vo of about 120Vpp. The equivalent coil Lm of the mechanical vibration part of the vibrating body 1 is 50 mH, and the equivalent capacitor Cm is 65 pF. The resonant frequency fm of the vibrating body 1 is 88 kHz, and the electric resonant frequency fe is 142 kHz.

FIG. 8(b) is a diagram showing the results of simulating the relationship between the output voltage Vo in the booster circuit 800A, the primary current and secondary current of the transformer 802, and the drive frequency. The minimum frequency f1 of the primary current of the transformer 802 is 101 kHz, and the anti-resonance frequency fa of the secondary current is 93.5 kHz, and f1/fa=1.08. The primary current of the transformer 802 at the anti-resonant frequency fa (=93.5 kHz) is 0.34 A, and the circuit power consumption is 96 mW (the power ratio in FIG. 7 is approximately 2.4), which is the same as in Example 1 described above. larger than In other words, it can be seen that when the anti-resonance frequency fa and the minimum frequency f1 are far apart and do not satisfy the relationship of Equation 6 above, power consumption increases.

FIG. 9A is a circuit diagram of a booster circuit 800B according to Comparative Example 1. The AC pulse signal Vi is input to the boost circuit 800B, and the AC voltage Vo boosted by the transformer 812 is applied to the piezoelectric element 204. Regarding the inductance of the booster circuit 800B, the coil 811 has an inductance of 18 μH, the primary coil of the transformer 812 has an inductance of 20 μH, and the secondary coil has an inductance of 5 mH. The capacitance Cd of the piezoelectric element 204 is 0.54 nF. The winding ratio of the transformer 812 is 16 times, the power supply is 3V, and an AC voltage Vo of about 120Vpp is output. Further, the equivalent coil Lm of the mechanical vibration portion of the vibrating body 1 is 50 mH, and the equivalent capacitor Cm is 65 pF. The resonant frequency fm of the vibrating body 1 is 88 kHz, and the electric resonant frequency fe is 142 kHz.

FIG. 9B is a diagram showing the results of simulating the relationship between the output voltage Vo in the booster circuit 800B, the primary current and secondary current of the transformer 812, and the drive frequency. The minimum frequency f1 of the primary current of the transformer 812 is 110 kHz, and the anti-resonance frequency fa of the secondary current is 93.5 kHz, and f1/fa=1.18. The primary current of the transformer 812 at the anti-resonant frequency fa (=93.5kHz) is 0.44A, and the circuit power consumption is 108mW (the power ratio in FIG. 7 is about 2.7). greater than 1. As described above, in Comparative Example 2 as well, power consumption increases when the anti-resonance frequency fa and the minimum frequency f1 are far apart and do not satisfy the relationship of Equation 6 above.

FIG. 10(a) shows the results of measuring the drive speed and circuit power consumption when the vibration actuator 23 is driven by a control device having each of Example 1 (boost circuit 105A) and Comparative Example 1 (boost circuit 800A). FIG. The general configuration of the vibration type actuator 23 is as described with reference to FIG. 2. Further, the configuration of the control device 100 is as described with reference to FIGS. 1 and 3, and the configurations of the booster circuits 105A and 800A are as described with reference to FIGS. 6 and 8, respectively.

The ratio (f1/fa) between the minimum frequency f1 and the anti-resonance frequency fa is 1.04 in Example 1 and 1.08 in Comparative Example 1. The booster circuit 105A in FIG. 7 and the booster circuit 800A in FIG. 8 are common except for different circuit constants. Therefore, even though they have the same circuit configuration, the power consumption in Example 1 is lower than that in Comparative Example 1. It can be seen that Note that when the vibration type actuator 23 is driven at high speed, the power consumption is the same in Example 1 and Comparative Example 1. This is because as the driving frequency approaches the resonant frequency fm of the vibrating body 1, the power consumed by the vibrating body 1 becomes dominant, and the proportion of the power consumed by the resonant circuit becomes smaller. FIG. 10(b) will be described later.

As explained above, by configuring the booster circuit so that the minimum frequency f1 in the primary current of the transformer and the anti-resonance frequency fa in the secondary current satisfy the relationship of Equation 6 above, the power consumption of the booster circuit is reduced. can be reduced.

<Second embodiment>
In the first embodiment, the drive circuit 120 including the booster circuit 105 (105A) suitable for driving the vibration actuator 23 in which one vibrating body 1 drives one contact body 2 has been described. On the other hand, in the second embodiment, a drive circuit including a booster circuit suitable for driving a vibration type actuator that drives one contact body using a plurality of vibrating bodies will be described.

FIG. 11A is a circuit diagram of a booster circuit 105B according to the second embodiment (Example 2). Note that the configuration of the control device other than the booster circuit 105B is similar to the control device 100 described in the first embodiment, and therefore illustration and description thereof will be omitted. The booster circuit 105B includes a coil 611 and a transformer 612 that correspond to the transformer 102 and coil 101 shown in FIG. The AC pulse signal Vi is input to the boost circuit 105B, and the AC voltage Vo boosted by the transformer 612 is applied to the three piezoelectric elements 613 connected in parallel. Here, for convenience, the three piezoelectric elements 613 connected in parallel are referred to as "piezoelectric elements 615." Further, it is assumed that the three piezoelectric elements 613 are substantially equivalent.

Regarding the inductance of the booster circuit 105B, the coil 611 has an inductance of 10 μH, the primary coil of the transformer 612 has an inductance of 89 μH, and the secondary coil has an inductance of 8 mH. Further, the capacitance Cd of the piezoelectric element 615 (combined capacitance of the three piezoelectric elements 613) is 1.38 nF. The winding ratio of the transformer 612 is 9.5 times, the power supply is 9V, and an AC voltage Vo of about 150Vpp is output. Further, when three vibrators each having a piezoelectric element 613 are considered as one vibrator, the equivalent coil Lm of the mechanically vibrating portion of the vibrator is 46 mH, and the equivalent capacitor Cm is 65 pF. The resonant frequency fm of the vibrating body is 92 kHz, and the electric resonant frequency fe is 132 kHz.

FIG. 11B is a diagram showing the results of simulating the relationship between the output voltage Vo of the booster circuit 105B, the primary current and secondary current of the transformer 612, and the drive frequency. The minimum frequency f1 of the primary current of the transformer 612 is 95 kHz, and the anti-resonance frequency fa of the secondary current is 94.2 kHz, f1/fa=1.01, which satisfies the relationship of Equation 6 above. The primary current of the transformer 612 at the anti-resonant frequency fa (=94.2 kHz) is 0.4 A, and the circuit power consumption is 222 mW. The relationship between the value of f1/fa and the power ratio in the booster circuit 105B is as shown in FIG.

Note that in the control device having the booster circuit 105B of the second embodiment, the minimum frequency fmin is set to 93 kHz and the maximum frequency fmax is set to 98 kHz in the drive frequency range. Further, the starting frequency fd is set in the range of 93.3 to 95.9 kHz.

In the second embodiment as well, the power consumption of the booster circuit is made such that the minimum frequency f1 in the primary current of the transformer and the anti-resonance frequency fa in the secondary current satisfy the relationship of Equation 6 above. can be reduced.

<Third embodiment>
FIG. 12A is a circuit diagram of a booster circuit 105C according to the third embodiment (Example 3). Note that the configuration of the control device other than the booster circuit 105C is similar to the control device 100 described in the first embodiment, so illustration and description thereof will be omitted. The booster circuit 105C includes a coil 621 and a transformer 622 that correspond to the transformer 102 and coil 101 shown in FIG. Further, the booster circuit 105C includes a first capacitor 623 connected in parallel to the coil 621 on the primary side of the transformer 622, and a second capacitor 624 connected in parallel to the piezoelectric element 625 on the secondary side of the transformer 622. The AC pulse signal Vi is input to the boost circuit 105C, and the AC voltage Vo boosted by the transformer 622 is applied to the piezoelectric element 625.

Regarding the inductance of the booster circuit 105C, the coil 621 has an inductance of 25 μH, the primary coil of the transformer 622 has an inductance of 50 μH, and the secondary coil has an inductance of 4.5 mH. Further, the capacitance Cd of the piezoelectric element 625 is 3.5 nF, and the capacitance of the second capacitor 624 is 3 nF. Although the minimum frequency f1 and the anti-resonance frequency fa can be changed individually depending on the constant of the second capacitor 624, in this embodiment, it is used mainly for the purpose of adjusting the minimum frequency f1. The first capacitor 623 is provided mainly for the purpose of suppressing voltage fluctuations, and has a capacitance of 1 μF. The winding ratio of the transformer 622 is 12 times, the power supply is 10V, and an AC voltage Vo of about 150Vpp is output. Further, the equivalent coil Lm of the mechanical vibration portion of the vibrating body having the piezoelectric element 625 is 0.1H, and the equivalent capacitor Cm is 281 pF. The resonant frequency fm of the vibrating body including the piezoelectric element 625 is 30 kHz, and the electric resonant frequency fe is 50 kHz.

FIG. 12(b) is a diagram showing the results of simulating the relationship between the output voltage Vo of the booster circuit 105C, the primary current and secondary current of the transformer 622, and the drive frequency. The minimum frequency f1 of the primary current of the transformer 622 is 33.0 kHz, and the anti-resonance frequency fa of the secondary current is 30.7 kHz, f1/fa=1.07, which satisfies the relationship in equation 6 above. ing. The primary current of the transformer 622 at the anti-resonant frequency fa (=33.0 kHz) is 1.8 A, and the circuit power consumption is 554 mW. The relationship between the value of f1/fa and the power ratio in the booster circuit 105C is as shown in FIG.

Note that in the control device having the booster circuit 105C of the third embodiment, the minimum frequency fmin is set to 31 kHz and the maximum frequency fmax is set to 35 kHz in the drive frequency range. Further, the starting frequency fd is set in the range of 30.4 to 33.3 kHz.

FIG. 10(b) is a diagram showing the results of measuring the driving speed of the contact body and the circuit power consumption when the vibration type actuator was driven by the control device having each of the resonance circuits of Example 3 and Comparative Example 3. Note that a traveling wave vibration type actuator 23B, which will be described later with reference to FIG. 15, was used as the actual device used to measure the circuit power consumption. In Example 3, as described above, f1/fa=1.07. Further, in Comparative Example 3, f1/fa was set to 1.66 in the circuit configuration of FIG. 12(a).

As shown in FIG. 10(b), it can be seen that the circuit power consumption in Example 3 is significantly smaller in the entire speed range than in Comparative Example 3. The difference in f1/fa values between Example 3 and Comparative Example 3 is larger than the difference in f1/fa values between Examples 1 and 2 and Comparative Examples 1 and 2 described above. In other words, for a configuration in which f1/fa is far from the range defined by Expression 6 above, by adopting a configuration that satisfies the condition of Expression 6 above, it is possible to significantly reduce power consumption.

In the third embodiment as well, the power consumption of the booster circuit is made such that the minimum frequency f1 in the primary current of the transformer and the anti-resonance frequency fa in the secondary current satisfy the relationship of Equation 6 above. can be reduced.

<Fourth embodiment>
In the fourth embodiment, a configuration will be described in which the vibration type drive device 20 described in the first embodiment is applied to a lens drive mechanism of an imaging device (optical device). FIG. 13 is a perspective view showing a schematic structure of a lens drive mechanism 900 of a lens barrel included in an imaging device. Note that illustration of the control device 100 is omitted. The lens drive mechanism 900 includes a lens holder 902, a vibrating body 901 that drives the lens holder 902, a pressure magnet 905, a first guide bar 903, a second guide bar 904, and a base (not shown).

The lens holder 902 is a component corresponding to the contact body 2 described with reference to FIG. The lens holder 902 includes a cylindrical main body part 902a, a holding part 902b that holds the vibrating body 901 and the pressure magnet 905, and a first guide bar 903 that forms a first guide part by fitting with the first guide bar 903. 1 guide portion 902c and a fall prevention portion 902d. A lens 907 is held in the main body portion 902a. The first guide bar 903 and the second guide bar 904 are arranged parallel to each other, and both ends of each of the first guide bar 903 and the second guide bar 904 are fixed to a base (not shown). . Note that the lens 907 (optical element) is assumed here to be a lens (focus lens) for performing an autofocus operation.

The pressure magnet 905 constituting the pressure means is composed of a permanent magnet and two yokes arranged at both ends of the permanent magnet. A magnetic circuit is formed between the pressure magnet 905 and the second guide bar 904, and an attractive force is generated between these members. As a result, the tips of the two projections provided on the vibrating body 901 are held pressed against the second guide bar 904 with a predetermined force, forming a second guide portion.

A certain gap is provided between the pressure magnet 905 and the second guide bar 904. Therefore, if the second guide section receives an external force, there is a possibility that the protrusion of the vibrating body 901 and the second guide bar 904 may become separated. However, in this case, the falling-off prevention part 902d provided on the lens holder 902 comes into contact with the second guide bar 904, and the holding part 902b of the lens holder 902 returns to its original position, so that the protrusion of the vibrating body 901 is configured so that it returns to a state in which it is in contact with the second guide bar 904.

The vibrating body 901 has the same structure as the vibrating body 1 described in the first embodiment, and a detailed explanation of the configuration will be omitted. By applying a two-phase AC voltage to the piezoelectric element of the vibrating body 901, elliptical vibration is generated in the two protrusions, and a frictional driving force is generated between the vibrating body 901 and the second guide bar 904. At this time, since the first guide bar 903 and the second guide bar 904 are fixed, the generated frictional driving force moves the lens holder 902 to the length of the first guide bar 903 and the second guide bar 904. It can be moved along the direction. In this way, an autofocus operation can be performed by adjusting the position of the lens 907.

Note that in the lens drive mechanism 900, a magnetic force (pressure magnet 905) is used as a pressure mechanism, but the present invention is not limited to this, and a biasing force from a spring may also be used. Further, the lens drive mechanism 900 is configured as a linear vibration type drive device, but is not limited to this, and may be configured using rotary vibration type actuators 23A and 23B, which will be described later with reference to FIGS. 14 and 15. A lens drive mechanism can also be configured. That is, the rotational force of the contact body is used to rotate the annular member holding the lens, and at this time, the amount of rotation of the annular member is adjusted to a straight line in the optical axis direction using a technique such as engagement of a cam pin and a cam groove. Convert to movement amount. Thereby, the lens can be moved in the optical axis direction.

The vibration type drive device is suitable for driving a focus lens (optical element) in an imaging device, but is not limited to this, and a similar configuration can also be used to drive a zoom lens (optical element). Further, the vibration type drive device can also be used as a mechanism for driving a lens (optical element) or an image sensor (optical element) to perform camera shake correction.

<Fifth embodiment>
In the fifth embodiment, a vibration type actuator that rotationally drives a contact body using a plurality of vibrating bodies 1 described with reference to FIG. 2 will be described. FIG. 14 is a diagram illustrating the configuration of a vibration type actuator 23A in the fifth embodiment, with a plan view shown on the upper side and a side view shown on the lower side.

The vibration type actuator 23A includes vibrating bodies 1A, 1B, and 1C and a contact body 2A. The vibrating bodies 1A, 1B, and 1C are equivalent to the vibrating body 1 described with reference to FIG. 2, and therefore, detailed description of their configurations will be omitted. The contact body 2A has a disc shape. The vibrating bodies 1A, 1B, and 1C are arranged so that the line connecting the respective two protrusions 202 (numerals are omitted in FIG. 14) is a tangent to a circle centered on the rotation center of the contact body 2A. They are held on one plane of an annular base plate 43 at equal intervals in the circumferential direction. The protrusions 202 of each of the vibrating bodies 1A, 1B, and 1C are in contact with one surface of the contact body 2A, and a rotating shaft 47 is coaxially fixed to the center of the contact body 2A. A disk-shaped scale portion 48 is coaxially fixed to the rotating shaft 47, and the scale portion 48 rotates at the same angular velocity as the contact body 2A. A position sensor 46 is arranged to face the scale section 48. Based on the result of the position sensor 46 reading the scale (not shown) of the scale section 48, the rotation angle (rotation position) or rotation speed of the contact body 2A can be detected, and feedback control is performed based on the detection result. be exposed.

A control device including a drive circuit including the booster circuit 105B described with reference to FIG. 11 is used to drive the vibration actuator 23A. The output voltage Vo output from the booster circuit 105B is supplied as a two-phase alternating voltage to the piezoelectric elements 204 of the vibrating bodies 1A, 1B, and 1C connected in parallel through the flexible cable 49. are driven simultaneously.

For example, by generating frictional driving force in the vibrating bodies 1A, 1B, and 1C in the directions shown by arrows M1, M2, and M3 in FIG. 14, the contact body 2A can be moved clockwise in the state shown in the upper row of FIG. It can be rotated. At this time, by using the three vibrating bodies 1A, 1B, and 1C, it is possible to obtain a large torque that is the sum of the torques generated by each vibrating body. Note that, as is well known, the rotation speed and rotation direction can be adjusted by adjusting the phases of the two-phase AC voltage.

<Sixth embodiment>
In the sixth embodiment, another example of a vibration type actuator that rotationally drives a contact body will be described. FIG. 15(a) is a perspective view showing a schematic configuration of a vibrating body 51 and a contact body 52 that constitute a vibration type actuator 23B in the sixth embodiment. The vibrating body 51 and the contact body 52 both have an annular shape and are arranged coaxially, and the contact body 52 is in contact with the vibrating body 51 in a rotatably supported state. In addition, in FIG. 15(a), the contact body 52 is shown with a portion cut away.

FIG. 15(b) is a plan view illustrating the electrodes of the piezoelectric element 204A provided on the vibrating body 51. The vibrating body 51 has a structure in which an annular and flat piezoelectric element 204A is adhered to the lower surface of an annular elastic body (the surface opposite to the contact surface with respect to the contact body 52). The piezoelectric element 204A is formed with an electrode pattern divided into 16 equal parts in the circumferential direction and divided into four phases.

A control device including a drive circuit having the booster circuit 105C described with reference to FIG. 12 is preferably used to drive the vibration actuator 23B. The contact body 52 can be rotationally driven by applying a predetermined AC voltage to the piezoelectric element 204A so that the wave number of progressive vibration of the vibrating body 51 becomes four waves during one rotation. Note that the wave number of the progressive vibrations generated in the vibrating body 51 is not limited to four waves. Furthermore, since the vibration type actuator that operates based on such a driving principle is well known, a more detailed explanation will be omitted.

FIG. 15(c) is a sectional view showing a schematic configuration of a rotational drive device 50 using a vibration type actuator 23B. In the rotary drive device 50, the vibrating body 51 is fixed to the housing 53 with screws or the like. Note that the vibrating body 51 is in contact with a friction material provided on the contact body 52. An output shaft 55 that extracts the rotational motion of the contact body 52 to the outside is rotatably supported by the housing 53 by a ball bearing 56, and a pressure spring 58 biases the contact body 52 to contact the vibrating body 51. , transmits the rotation of the contact body 52 to the output shaft 55.

The output shaft 55 is connected to a drive unit 60 of various devices using the rotation drive device 50 as a drive source via a mechanism not shown. ).

FIG. 16A is a front view showing a schematic configuration of a pan head device 70 including a rotational drive device 50. The pan head device 70 has a structure in which a camera (imaging device, rotated device) fixed to a mounting base 71 (holding member) can be rotated in the panning direction by the rotation drive device 50. FIG. 16(b) is a front view showing the configuration of a transfer drum 81 (rotary drum) of an image forming apparatus or the like, which is rotationally driven by the rotational drive device 50. The transfer drum 81 is directly connected to the output shaft 55 and rotates in response to the rotational driving force of the output shaft 55.

Although the present invention has been described above in detail based on its preferred embodiments, the present invention is not limited to these specific embodiments, and the present invention may take various forms without departing from the gist of the present invention. included. For example, the object to be driven by the control device including the booster circuit according to the present embodiment is not limited to a vibration type actuator, but can be used to control a vibration device using a piezoelectric element, a power generation device, a piezoelectric transducer, etc. . Further, in the above embodiment, the movably arranged contact body is premised on a configuration in which it moves relative to the fixed vibrating body, but the configuration may be reversed.

1 Vibrating body 2 Contact body 20 Vibrating drive device 23 Vibrating actuator 100 Control device 102 Transformer 110 Control unit 120 Drive circuit 203 Elastic body 204 Piezoelectric element

Claims (15)

A vibration type actuator,
A vibration type drive device comprising: a control device that controls driving of the vibration type actuator;
The vibration type actuator is
a vibrating body having an elastic body and an electro-mechanical energy conversion element joined to the elastic body;
a contact body that contacts the elastic body,
The control device includes:
a drive circuit having a transformer that converts an input signal into an alternating current voltage applied to the electro-mechanical energy conversion element;
a control unit that controls the frequency, phase, and voltage of the input signal,
When the frequency at which the primary current of the transformer becomes minimum is f1, and the frequency at which the secondary current of the transformer becomes minimum is fa, the relationship 1.00≦f1/fa≦1.07 is satisfied. A vibration type drive device characterized by: The vibration type drive device according to claim 1, wherein the following relationship is satisfied, where fd is the activation frequency of the vibration type actuator. The vibration according to claim 1 or 2, wherein the relationship fmin<fa≦f1<fmax is satisfied, where fmin is the minimum frequency and fmax is the maximum frequency in the drive frequency range of the vibration type actuator. Mold drive device. The f1 is a resonant frequency that can be changed by at least the secondary coil of the transformer, the capacitance of the electro-mechanical energy conversion element, and the equivalent coil or equivalent capacitor of the mechanically vibrating part of the vibrating body. The vibration type drive device according to any one of claims 1 to 3, characterized in that: The fa is a resonant frequency that can be changed by at least the capacitance of the electro-mechanical energy conversion element and an equivalent coil and an equivalent capacitor of the mechanically vibrating portion of the vibrating body. 5. The vibration type drive device according to any one of 1 to 4. The drive circuit includes a pulse signal generation circuit that generates an AC pulse signal as the input signal by switching a DC power supply using a pulse signal whose phase is shifted by 180 degrees,
6. The vibration type drive device according to claim 1, wherein the transformer generates the AC voltage by boosting the AC pulse signal to a predetermined voltage. In the vibration type actuator, the two-phase alternating current voltage having the same frequency and a predetermined phase difference is applied to the electro-mechanical energy converting element, and vibration excited in the vibrating body causes the vibration between the contact body and the vibration type actuator. The vibrating body moves relative to the
7. The vibration type drive device according to claim 6, wherein the pulse signal generation circuit outputs the two-phase alternating current pulse signal having the predetermined phase difference to the drive circuit. The vibration type drive device according to claim 1, wherein the drive circuit includes a capacitor connected in parallel with the electro-mechanical energy conversion element. 9. The vibration type drive device according to claim 1, wherein the drive circuit includes a coil connected in series with the transformer on the primary side of the transformer. 10. The vibration type drive device according to claim 9, wherein the drive circuit includes a capacitor connected in parallel with the coil on the primary side of the transformer. The vibration type drive device according to any one of claims 1 to 10,
An imaging device comprising: an optical element driven by a vibration-type actuator included in the vibration-type drive device. The vibration type drive device according to any one of claims 1 to 10,
A pan head device comprising: a holding member for fixing a rotated device, which is driven by a vibration type actuator included in the vibration type drive device. The vibration type drive device according to any one of claims 1 to 10,
An image forming apparatus comprising: a rotating drum driven by a vibration type actuator included in the vibration type drive device. The vibration type drive device according to any one of claims 1 to 10,
A device comprising: a component driven by a vibration type actuator included in the vibration type drive device. A control device for controlling the drive of a vibration type actuator,
a pulse signal generation circuit that generates an AC pulse signal;
a transformer that converts the AC pulse signal input from the pulse signal generation circuit into an AC voltage applied to an electro-mechanical energy conversion element included in the vibration type actuator;
a control unit that controls the frequency, phase, and voltage of the AC voltage by controlling the frequency, phase, and voltage of the AC pulse signal;
When the frequency at which the primary current of the transformer becomes minimum is f1, and the frequency at which the secondary current of the transformer becomes minimum is fa, the relationship 1.00≦f1/fa≦1.07 is satisfied. A control device for a vibration type actuator, which is characterized by:

Images