JP2013162577A - Electrostrictive element driving device, exposure device, and lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostrictive element driving device that can reduce the hysteresis property of a piezo element Pz.SOLUTION: A piezo element driving device 1 detects the charging voltage Vc1 of a capacitor C1 as a voltage detection signal Vq by means of a voltage detection circuit 4, compares the voltage detection signal Vq with a command input Vin by means of a control unit 3, and controls the output voltage V1 of a piezo driving power supply unit 20 such that the charging voltage Vc1 of the capacitor C1 will be a value corresponding to the command input Vin. In this case, because the charged charge amount of the capacitor C1 and the charged charge amount of a piezo element Pz become the same, controlling the charging voltage (charged charge amount) of the capacitor C1 by the command input Vin allows the charged charge amount of the piezo element Pz to be controlled consequently. This allows the piezo element Pz to be charged by the charge amount corresponding to the command input Vin, and allows the hysteresis property of the piezo element Pz to be reduced.

Description

  The present invention relates to an electrostrictive element driving apparatus, an exposure apparatus, and a lens driving apparatus for driving an electrostrictive element such as a piezo element.

  An electrostrictive element is an element that generates displacement when a voltage is applied. A typical example of the electrostrictive element is a piezoelectric element (piezoelectric element). This piezo element is expected to be a promising actuator in the future because it can increase the amount of displacement by being laminated, and has low noise and low power consumption.

  By the way, in this piezo element, the relationship between the applied voltage and the displacement shows not a proportional relationship but a hysteresis characteristic. For this reason, an actuator using a piezo element is not always in the same position even when the same voltage is applied, and the position varies with respect to the target position.

  For this reason, various methods have been proposed as a driving method for reducing the influence of hysteresis of the piezoelectric element. As one of the methods, a method of connecting a capacitor in series with a piezo element has been proposed (see Non-Patent Document 1).

  FIG. 9 is a diagram illustrating an example of a drive circuit for a piezo element, FIG. 10A illustrates a general piezo element drive circuit, and FIG. 10B is described in Non-Patent Document 1 described above. 2 shows a piezoelectric element driving circuit. The general piezo element drive circuit shown in FIG. 10A is a circuit that is driven by simply applying a voltage to the piezo element Pz. A voltage is applied from the variable voltage source E to the piezo element Pz through the resistor R. Drive. In the driving method shown in FIG. 9A, for example, as shown in FIG. 3A, a significant hysteresis characteristic is generated with respect to a change in applied voltage. The piezoelectric element driving circuit described in Non-Patent Document 1 shown in FIG. 10B inserts a capacitor C1 in series with the piezoelectric element Pz when the piezoelectric element Pz is driven from the variable voltage source E via the resistor R. This reduces the influence of the hysteresis of the piezo element.

  Patent Document 1 discloses a related piezo drive circuit. The piezo drive circuit described in Patent Document 1 is intended to easily adjust for variations in characteristics of individual piezo vibrators. In this piezo drive power supply unit, an on / off control signal for driving a piezo vibrator is input to a resistor module in which a plurality of resistors are connected in parallel, and an analog switch circuit uses the selection signal to select one of the resistors in the resistor module. One resistor is selected, and the signal passing through the selected resistor is compared with the reference voltage in the operational amplifier circuit, and a voltage proportional to the difference is applied to the piezo vibrator via the driver circuit. The output is fed back to the operational amplifier circuit through a capacitor.

  Patent Document 2 discloses a drive mechanism using a related piezo element. The moving mechanism described in Patent Document 2 is intended to drive a parallel link that holds an optical element of a projection optical system of an exposure apparatus.

JP-A-5-177833 JP 2011-159861 A

H. Kaizuka et al, “A simple way to reduce hysteresis and creep when using piezoelectric actuators”, Jpn. J. Appl. Phys., Vol. 27, No. 5, pp. L773-L776 (1988), Physics Published by the Journal Publishing Association

The method described in Non-Patent Document 1 is a method of connecting a capacitor in series with a piezo, and an experimental effect of reducing hysteresis can be obtained simply by connecting a capacitor in series with the piezo element Pz. .
However, on the other hand, the voltage applied to the piezo element is divided by the capacitor connected in series with the piezo element Pz, so that the change in the capacitance of the piezo element (the capacitance caused by hysteresis) In accordance with (change), the voltage applied to the piezo element Pz and the capacitor C1 also changes. For this reason, the effect of reducing the hysteresis is fluctuated by the change in the voltage applied to the piezo element Pz and the capacitor C1 due to the change in the capacitance of the piezo element.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electrostrictive element driving apparatus, an exposure apparatus, and an electrostrictive element that can control the electrostrictive element by reducing the hysteresis characteristics of the electrostrictive element. The object is to provide a lens driving device.

  The present invention has been made to solve the above-described problems, and the electrostrictive element driving device of the present invention outputs an DC voltage applied to the electrostrictive element and can variably control the magnitude of the voltage. Detected by an element drive power supply unit, a charge charge amount detection unit for detecting the charge amount of the electrostrictive element charged by the electrostrictive element drive power supply unit, an externally input command signal, and the charge charge amount detection unit And controlling the electrostrictive element driving power supply unit so that the charge amount of the electrostrictive element is set to a value corresponding to the command signal using the detected charge charge amount of the electrostrictive element. A control unit, wherein the control unit controls the amount of displacement of the electrostrictive element by charging the electrostrictive element with an amount of charge corresponding to the externally input command signal. .

  In addition, the present invention includes the above-described electrostrictive element driving device, and the electrostrictive element is driven by using the electrostrictive element driving device to move the lens position or the stage position of the optical system. It is an exposure apparatus.

  According to another aspect of the present invention, there is provided a lens driving device comprising the field electrostrictive element driving device, wherein the electrostrictive element is driven using the electrostrictive element driving device to move the lens position of the optical system. It is.

  The electrostrictive element driving device of the present invention can control the electrostrictive element by reducing the hysteresis characteristic of the electrostrictive element.

1 is a block diagram showing a configuration of a piezo element driving apparatus according to a first embodiment of the present invention. It is a figure which shows the circuit structure of the piezoelectric element drive device shown in FIG. It is a figure which shows the reduction effect of the hysteresis characteristic of the piezoelectric element in this embodiment. It is a block diagram which shows the structure of the piezoelectric element drive device concerning 2nd Embodiment of this invention. It is a figure which shows the circuit structure of the piezoelectric element drive device shown in FIG. It is a figure which shows the example of the waveform of each part in the piezoelectric element drive device shown in FIG. It is a block diagram which shows the structure of the piezoelectric element drive device concerning 3rd Embodiment of this invention. It is a figure which shows the circuit structure of the piezoelectric element drive device shown in FIG. It is a figure which shows the example of exposure apparatus. 1 is a diagram illustrating a circuit configuration of a piezo element driving device described in Non-Patent Document 1. FIG.

In the electrostrictive element driving device of the present invention, when a DC voltage is applied to the electrostrictive element and displaced, the charge amount of the electrostrictive element is detected, and the electrostrictive element is detected according to a command signal input from the outside. Control the amount of charge.
As a result, the electrostrictive element driving device of the present invention can control the amount of charge of the electrostrictive element even when the capacitance changes due to the hysteresis characteristic of the electrostrictive element. Characteristics can be reduced.
Embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment]
(Schematic configuration of the piezoelectric element driving apparatus of the first embodiment)
FIG. 1 is a block diagram showing a configuration of a piezo element driving apparatus according to the first embodiment of the present invention.
A piezo element driving apparatus 1 shown in FIG. 1 is configured to receive a command input Vin (voltage signal) from the host side (external) and to control the displacement amount of the piezo element (Pz) 2 in accordance with the command input Vin. Has been. The piezo element driving device 1 detects the charge amount of the piezo element (Pz) 2 when a DC voltage is applied to the piezo element (Pz) 2 and displaced, and the detected charge amount and the command input Vin are detected. (More precisely, the command signal Vref generated from the command input Vin is compared, and control is performed so that the charge amount of the piezo element (Pz) 2 is set to a value corresponding to the command input Vin. Thereby, the charge amount of the piezo element (Pz) 2 is controlled to be proportional to the command input Vin, and the hysteresis characteristic of the piezo element (Pz) 2 is reduced. In the following description, the piezo element (Pz) 2 is simply referred to as “piezo element Pz”.

  In the piezo element driving apparatus 1, a capacitor C1 is connected in series to a piezo element Pz that is a capacitive element. The piezo element driving device 1 controls the charge charge amount of the piezo element Pz by controlling the charge voltage (charge charge amount) charged to the capacitor C1 by the command input Vin. That is, the amount of charge charged in the capacitor C1 is the same as the amount of charge charged in the piezo element Pz, and the piezo element driving device 1 sets the charge voltage (charge amount) of the capacitor C1 according to the command input Vin. By controlling, the amount of displacement of the piezo element Pz is indirectly controlled by controlling the amount of displacement.

  The piezo element driving apparatus 1 includes a control unit 3, a piezo driving power supply unit 20, a piezo element Pz, and a capacitor C1. The control unit 3 includes a command signal generation circuit 10 that is a buffer circuit for the command input Vin, a regulator circuit 11, and a charge amount feedback circuit 31. Further, the piezo element driving device 1 has a voltage detection circuit 4 connected to both ends of the capacitor C1. The voltage detection circuit 4 is constituted by a resistance voltage dividing circuit of a resistor R1 and a resistor R2, and the charging voltage of the capacitor C1 is detected by detecting the voltage generated in the voltage dividing resistor R2 of the resistance voltage dividing circuit. The

The command signal generation circuit 10 receives a command input Vin that indicates the amount of displacement of the piezo element Pz, and outputs the command input Vin as a command signal Vref buffered by an operational amplifier (operational amplifier).
The regulator circuit 11 is composed of a PI (proportional / integral) circuit using an operational amplifier, and receives a command signal Vref output from the command signal generation circuit 10 and a charge amount feedback signal Qfbk output from the charge amount feedback circuit 31. Input signal. The regulator circuit 11 inputs the command signal Vref to the node N11 via the resistor R11, inputs the charge amount feedback signal Qfbk to the node N11 via the resistor R12, and associates these signals Vref and Qfbk at the node N11. To generate an error signal. The regulator circuit 11 performs a proportional operation and an integration operation on the error signal between the command signal Vref and the charge amount feedback signal Qfbk, and sends a signal resulting from the proportional operation and the integration operation to the piezo drive power supply unit 20. Output as voltage command signal Vd.

The piezo drive power supply unit 20 is a circuit that outputs a DC voltage (voltage between the node A and the node B) V1 applied to a series circuit of the piezo element Pz and the capacitor C1. The piezo drive power supply unit 20 includes a PWM (Pulse Width Modulation) control unit 20A, a bridge circuit including transistors Tr1, Tr2, Tr3, and Tr4 that are N-channel type power MOSFETs, and a smoothing circuit 21. doing.
The PWM control unit 20A generates a PWM signal corresponding to the magnitude and polarity of the voltage command signal Vd output from the regulator circuit 11, and also uses a gate signal for on / off control of the transistors Tr1 to Tr4 by the PWM signal. Generate. In the bridge circuit including the transistors Tr1 to Tr4, the drain terminals of the transistors Tr1 and Tr2 on the upper arm side are connected to a power source + HV (for example, DC + 150V). The source terminal of the transistor Tr1 is connected to the drain terminal of the transistor Tr3 on the lower arm side, and the source terminal of the transistor Tr3 is connected to the circuit ground G. The source terminal of the transistor Tr2 is connected to the drain terminal of the transistor Tr4 on the lower arm side, and the source terminal of the transistor Tr4 is connected to the circuit ground G.

  A voltage generated between a connection point (node N21) between the transistor Tr1 and the transistor Tr3 and a connection point (node N22) between the transistor Tr2 and the transistor Tr4 is connected to the capacitor C1 and the piezoelectric element via the smoothing circuit 21. The voltage V1 is applied to both ends (node A and node B) of the Pz series circuit. The voltage V1 output from the piezo drive power supply unit 20 is controlled by the voltage command signal Vd, and the polarity of the output voltage V1 is also controlled. That is, the piezo drive power supply unit 20 is configured to change the voltage value applied to the piezo element Pz and its polarity.

  The smoothing circuit 21 is composed of an LC smoothing circuit. A harmonic component of the voltage (PWM waveform voltage) output from the node N21 of the piezo drive power supply unit 20 is blocked by the LC filter including the reactor L1 and the capacitor C21. A connection point between the reactor L1 and the capacitor C21 is connected to one end (node A) of the capacitor C1. Further, the harmonic component of the voltage (PWM waveform voltage) output from the node N22 of the piezoelectric drive power supply unit 20 is blocked by the LC filter including the reactor L2 and the capacitor C22. A connection point between the reactor L2 and the capacitor C22 is connected to one end (node B) of the piezo element Pz.

  A voltage detection circuit (resistance voltage dividing circuit) 4 formed of a series circuit of resistors R1 and R2 is connected in parallel to both ends of the capacitor C1. A voltage generated in the voltage dividing resistor R2 of the resistors R1 and R2 is input to the charge amount feedback circuit 31 as a voltage detection signal (a detection signal of the charge amount of charge of the capacitor C1) Vq of the capacitor C1. The charge amount feedback circuit 31 generates a charge amount feedback signal Qfbk based on the voltage detection signal Vq. The charge amount feedback signal Qfbk is input to the regulator circuit 11 as a feedback signal of the charge amount of the capacitor C1 (same as the charge amount of the piezo element Pz).

  The piezo element driving apparatus 1 configured as described above detects the charging voltage (charged charge amount) of the capacitor C1 connected in series to the piezo element Pz when applying a DC voltage to the piezo element Pz and displacing it. A charge amount feedback signal Qfbk is generated based on the charge amount detection signal and input to the regulator circuit 11. The regulator circuit 11 takes a difference between the command signal Vref and the charge amount feedback signal Qfbk at the addition point (node 11), and charges the capacitor C1 so that the command signal Vref and the charge amount feedback signal Qfbk match. Control the voltage (charge charge amount). In this case, since the charge amount of the capacitor C1 and the charge amount of the piezo element Pz are the same, the charge amount of the piezo element Pz is indirectly controlled by controlling the charge amount of the capacitor C1. be able to.

  As described above, in the piezo element driving apparatus 1 according to the present embodiment, a necessary voltage is applied to the piezo element Pz according to the command input Vin. For example, when the voltage V1 is applied to the series circuit (between the node A and the node B) of the piezo element Pz and the capacitor C1, the voltage Vpz applied to the piezo element Pz having the capacitance C0 is connected in series. Since the voltage is divided with the capacitor C1, the voltage Vpz applied to the piezo element Pz is

Vpz = (C1 / (C0 + C1)) × V1,
It becomes.

The voltage Vc1 applied to the capacitor C1 is
Vc1 = (C0 / (C0 + C1)) × V1,
It becomes.

Then, the voltage detection signal Vq detected by the voltage dividing resistor R2 of the voltage detection circuit 4 has the terminal voltage of the capacitor C1 as Vc1,
Vq = (R2 / (R1 + R2)) × Vc1,
It becomes.

Then, the piezo element driving device 1 generates the charge amount feedback signal Qfbk based on the voltage detection signal Vq of the capacitor C1 detected by the voltage dividing resistor R2, and controls the voltage Vc1 of the capacitor C1 by the control unit 3. Thus, the charge amount of the piezo element Pz is controlled.
Thereby, the piezo element driving apparatus 1 can control the charge amount of the piezo element Pz according to the command input Vin. Therefore, even when the capacitance changes due to the hysteresis characteristic of the piezo element Pz, the hysteresis characteristic can be reduced by controlling the charge amount of the piezo element Pz to be a desired value.

(Specific circuit configuration of the piezoelectric element driving apparatus of the first embodiment)
FIG. 2 is a diagram showing a specific circuit configuration of the piezoelectric element driving apparatus 1 according to the first embodiment. The command signal generation circuit 10, the regulator circuit 11, and the like of the piezoelectric element driving apparatus 1 shown in FIG. It is the figure which showed the electric charge amount feedback circuit 31 with the more concrete circuit. The sign of the polarity (+ or −) shown in the circuit of the piezo element driving device 1 indicates that the current Is flowing from the piezo drive power supply unit 20 to the piezo element Pz is in the direction shown (from the node B side to the node A side). The polarity of the signal of each part in the case of flowing is shown.

  In the piezo element driving apparatus 1 shown in FIG. 2, the command signal generation circuit 10 includes an operational amplifier (operational amplifier) IC1 and a resistor R3 to which one end is connected to the negative input terminal of the operational amplifier IC1 and the command input Vin is applied to the other end. And a resistor R4 connected between the negative input terminal and the output terminal of the operational amplifier IC1. The + side input terminal of the operational amplifier IC1 is connected to the circuit ground G. A voltage signal that indicates the amount of displacement of the piezo element Pz is input to the command signal generation circuit 10 via the resistor R3 as the command input Vin. The command signal generation circuit 10 is an inverting amplification circuit, and this command signal generation circuit 10 inverts and amplifies the command input Vin input through the resistor R3 (inverts and amplifies the polarity of the signal) as a command signal Vref. Output. In the example shown in FIG. 2, the command signal Vref is a negative signal.

The regulator circuit 11 includes an operational amplifier (operational amplifier) IC2, a resistor R11 having one end connected to the negative input terminal of the operational amplifier IC2 and the command signal Vref applied to the other end, and one end connected to the negative input terminal of the operational amplifier IC2. Is connected, and the other end is connected to one end of the capacitor C11, the resistor R14 is connected to the other end of the resistor R14, the other end is connected to the output terminal of the operational amplifier IC2, and the negative input of the operational amplifier IC2 And a resistor R12 to which one end is connected to the terminal and the charge amount feedback signal Qfbk is applied to the other end. The + side input terminal of the operational amplifier IC2 is connected to the circuit ground G.
The regulator circuit 11 constitutes a PI (proportional / integral) circuit. The regulator circuit 11 adds the command signal Vref (−polarity signal) and the charge amount feedback signal Qfbk (+ polarity signal) at the node N11 to obtain an error signal, and is proportional to the error signal. The voltage command signal Vd is generated and output by the proportional operation and the integral operation.

  The piezo drive power supply unit 20 includes a PWM control unit 20A, a bridge circuit including transistors Tr1 to Tr4, and a smoothing circuit 21. The configuration of the piezo drive power supply unit 20 has already been described with reference to FIG.

  In addition, a resistance voltage dividing circuit including a resistor R1 and a resistor R2 is connected as a voltage detection circuit 4 to both ends of a capacitor C1 connected in series with the piezo element Pz. In this voltage detection circuit 4, one end of the resistor R1 is connected to one end (node A) of the capacitor C1, the other end of the resistor R1 is connected to one end of the resistor R2, and the other end of the resistor R2 is the other end of the capacitor C1 ( Connection point between the capacitor C1 and the piezo element Pz). The voltage generated at both ends of the voltage dividing resistor R2 is input to the charge amount feedback circuit 31 as the voltage detection signal Vq.

The charge amount feedback circuit 31 includes a differential amplifier circuit 32 and an inverting amplifier circuit 33.
The differential amplifier circuit 32 is a circuit that amplifies only the potential difference between two input voltages. Specifically, the voltage generated across the voltage dividing resistor R2 in the voltage detection circuit 4 connected in parallel to the capacitor C1. (Voltage detection signal) Vq is amplified and output. In the differential amplifier circuit 32, one end of the resistor R31 is connected to the negative input terminal of the operational amplifier IC3, and the other end of the resistor R31 is connected to one end of the resistor R2 (a connection point between the resistor R2 and the capacitor C1). Also, one end of the resistor R32 is connected to the + side input terminal of the operational amplifier IC3, and the other end of the resistor R32 is connected to the other end of the resistor R2 (a connection point between the resistor R1 and the resistor R2). One end of the resistor R33 is connected to the + side input terminal of the operational amplifier IC3, and the other end of the resistor R33 is connected to the circuit ground G. A resistor R34 is connected between the negative input terminal and the output terminal of the operational amplifier IC3.

  The inverting amplifier circuit 33 is a circuit that generates the charge amount feedback signal Qfbk by inverting and amplifying the signal Vq ′ output from the differential amplifier circuit 32. In the inverting amplifier circuit 33, a resistor R36 is connected between the negative input terminal and the output terminal of the operational amplifier IC4, one end of the resistor R35 is connected to the negative input terminal of the operational amplifier IC4, and the other end of the resistor R35 is It is connected to the output terminal of the operational amplifier IC3.

  The charge amount feedback circuit 31 having the above configuration detects the voltage detection signal Vq generated at both ends of the voltage dividing resistor R2 by the differential amplifier circuit 32, and inverts the signal Vq ′ detected by the differential amplifier circuit 32. Inverted and amplified by 33 and output as a charge amount feedback signal Qfbk. The charge amount feedback signal Qfbk is input to the addition point (node N11) of the regulator circuit 11 via the resistor R12.

  Here, when the voltage generated across the capacitor C1 is Vc1, the output voltage (voltage detection signal) Vq of the voltage dividing resistor R2 of the voltage detection circuit 4 is:

Vq = (R2 / (R1 + R2)) × Vc1,
It becomes.

  The voltage detection signal Vq detected by the voltage dividing resistor R2 is amplified by the differential amplifier circuit 32 in the charge amount feedback circuit 31 and output as an output voltage Vq '. The output voltage Vq ′ of the differential amplifier circuit 32 is obtained when the resistance value of the resistor R31 is equal to the resistance value of the resistor R32, and the resistance value of the resistor R33 is equal to the resistance value of the resistor R34.

Vq ′ = − (R34 / R31) × Vq,
It becomes. In the example shown in FIG. 2, the output voltage Vq ′ of the differential amplifier circuit 32 is a negative signal.

The output voltage Vq ′ of the differential amplifier circuit 32 is input to the inverting amplifier circuit 33. The inverting amplifier circuit 33 inverts and amplifies the output voltage Vq ′ of the differential amplifier circuit 32 to generate a charge amount feedback signal Qfbk. .
This charge amount feedback signal Qfbk is
Qfbk = + (R36 / R35) × (R34 / R31) × Vq,
It becomes. In the example shown in FIG. 2, the charge amount feedback signal Qfbk is a + polarity signal.

  As described above, the piezo element driving device 1 generates the charge amount feedback signal Qfbk based on the voltage detection signal Vq of the capacitor C1 detected by the voltage dividing resistor R2 in the voltage detection circuit 4, and the control unit 3 By controlling the voltage Vc1 of the capacitor C1, the charge amount of the piezo element Pz is controlled. Thereby, the piezo element driving apparatus 1 can control the charge amount of the piezo element Pz according to the command input Vin. For this reason, even when the capacitance changes due to the hysteresis characteristic of the piezo element Pz, the charge amount of the piezo element Pz can be controlled to be a value corresponding to the input command Vin. It is possible to reduce the hysteresis characteristic.

FIG. 3 is a diagram showing the effect of reducing the hysteresis characteristics in the piezo element driving apparatus 1 of the present embodiment. FIG. 3A shows the hysteresis characteristics in the case of a general driving method, that is, when a voltage is simply applied to the piezo element Pz (see FIG. 9A), and FIG. The hysteresis characteristic at the time of using the piezoelectric element drive device 1 of the form is shown.
In the case of the general driving method shown in FIG. 3A, the amount of displacement (vertical axis) shows a significant hysteresis characteristic with respect to the change in applied voltage (horizontal axis) of the piezo element Pz, and the hysteresis width Occurs up to about 15%.
On the other hand, in the case of the piezo element driving apparatus 1 of this embodiment shown in FIG. 3B, the hysteresis of the displacement (vertical axis) with respect to the change in the command input Vin (horizontal axis) of the piezo element Pz. The characteristics are greatly reduced, and the hysteresis width is about 6% at the maximum. As described above, by using the piezo element driving apparatus 1 of the present embodiment, it is possible to greatly reduce the hysteresis characteristics when driving the piezo element Pz.

[Second Embodiment]
FIG. 4 is a block diagram showing a configuration of a piezo element driving device path according to the second embodiment of the present invention.
In addition to the charge amount feedback circuit 31, the piezo element driving apparatus 1A of the second embodiment is configured by newly providing a current feedback circuit 41 that detects a current flowing through the piezo element Pz. Thus, by using the current feedback loop and the charge amount feedback loop in combination, the current flowing through the piezo element Pz is stably controlled, and as a result, the responsiveness when driving the piezo element Pz is improved (for example, overshoot). Shoot can be suppressed).

  The piezo element driving apparatus 1A shown in FIG. 4 is different from the piezo element driving apparatus 1 shown in FIG. 1 in that a current detection resistor Rs and a current feedback circuit 41 are newly added. Other configurations are the same as those of the piezoelectric element driving apparatus 1 shown in FIG. For this reason, the same code | symbol is attached | subjected to the same component and the overlapping description is abbreviate | omitted.

  In the piezo element driving apparatus 1A shown in FIG. 4, as in the piezo element driving apparatus 1 shown in FIG. 1, a command input Vin corresponding to the displacement amount of the piezo element Pz is input from the host side (external), and the piezo element Pz. However, the length is changed in accordance with the command input Vin (more precisely, the command signal Vref generated from the command input Vin).

  In the piezo element driving apparatus 1A, the current detection resistor Rs is a resistor for detecting the current Is flowing through the piezo element Pz (and the capacitor C1). A voltage (current detection signal) Vis generated at both ends of the current detection resistor Rs is input to the current feedback circuit 41. The current feedback circuit 41 generates a current feedback signal Ifbk based on the current detection signal Vis. The current feedback signal Ifbk is input to the regulator circuit 11 and input to the addition point (node N11) via the resistor R13 in the regulator circuit 11.

  The piezo element driving apparatus 1 having the above configuration has two feedback loops of a current feedback circuit 41 and a charge amount feedback circuit 31. Among these, the current feedback circuit 41 is a current loop that directly controls the current flowing through the piezo element Pz in accordance with the command signal Vref, and is a loop that responds at high speed to control the current Is flowing through the piezo element Pz. is there. On the other hand, the charge amount feedback circuit 31 is a feedback loop that controls the amount of charge (time integrated amount of the current Is) charged in the capacitor C1 by the current flowing through the piezo element Pz, and the response is delayed compared to the current feedback loop. This is a loop that acts as an outer loop of the feedback loop (an outer loop in the sense that the response is slower than the current feedback loop).

  That is, in the piezo element driving apparatus 1, in response to a change in the command input Vin (more precisely, the command signal Vref), a current feedback loop first acts to control the current flowing through the piezo element Pz, and after that, The amount of charge stored in the piezo element Pz (more precisely, the capacitor C1) is controlled. As described above, by using the current feedback loop and the charge amount feedback loop in combination, the current flowing through the piezo element Pz can be stably controlled, and an excessive current flows through the piezo element Pz or the piezo element Pz. It is possible to suppress large fluctuations in the flowing current (for example, occurrence of excessive overshoot). As a result, the charge amount of the piezo element Pz is controlled at high speed and stably.

FIG. 5 is a diagram showing a circuit configuration of the piezoelectric element driving apparatus 1A of the second embodiment. The command signal generation circuit 10, the regulator circuit 11, and the charge amount in the piezoelectric element driving apparatus 1 shown in FIG. 3 is a diagram illustrating a more specific circuit configuration of a feedback circuit 31 and a current feedback circuit 41. FIG. The sign of the polarity (+ or −) shown in the circuit of the piezo element driving apparatus 1A indicates that the current Is flowing from the piezo driving power supply unit 20 to the piezo element Pz is in the direction shown (from the node B side to the node A side). The polarity of the signal of each part when flowing toward is shown.
Hereinafter, only the parts different in configuration from the piezo element driving apparatus 1 of the first embodiment shown in FIG. 2 will be described, and redundant description will be omitted.

  In the piezo element driving apparatus 1 shown in FIG. 5, the regulator circuit 11 constitutes a PI (proportional / integral) circuit. The regulator circuit 11 adds a current feedback signal Ifbk (+ polarity signal) and a charge amount feedback signal Qfbk (+ polarity signal) to the command signal Vref (−polarity signal), and outputs an error signal thereof. The proportional operation and the integration operation are performed on the error signal, and the voltage command signal Vd is generated and output by the proportional operation and the integration operation.

The current feedback circuit 41 includes a differential amplifier circuit 42 and an inverting amplifier circuit 43.
The differential amplifier circuit 42 is a circuit that amplifies only a potential difference between two input voltages. Specifically, a voltage (current detection signal) Vis generated at both ends of a resistor Rs that detects a current Is flowing through the piezo element Pz. Is amplified and output. In the differential amplifier circuit 32, one end of the resistor R41 is connected to the negative input terminal of the operational amplifier IC5, and the other end of the resistor R41 is connected to one end of the resistor Rs (a connection point between the piezo drive power supply unit 20 and the resistor Rs). Is done. Also, one end of the resistor R42 is connected to the + side input terminal of the operational amplifier IC5, and the other end of the resistor R42 is connected to one end of the piezo element Pz (a connection point between the resistor Rs and the piezo element Pz). One end of the resistor R43 is connected to the + side input terminal of the operational amplifier IC5, and the other end of the resistor R43 is connected to the circuit ground G. A resistor R34 is connected between the negative input terminal and the output terminal of the operational amplifier IC5.

  The inverting amplifier circuit 43 is a circuit that inverts and amplifies the signal output from the differential amplifier circuit 42 to generate a current feedback signal Ifbk. In the inverting amplifier circuit 43, a resistor R46 is connected between the negative input terminal and the output terminal of the operational amplifier IC6, one end of the resistor R45 is connected to the negative input terminal of the operational amplifier IC6, and the other end of the resistor R45 is It is connected to the output terminal of the operational amplifier IC5. Further, the + side input terminal of the operational amplifier IC6 is connected to the circuit ground G.

  The current feedback circuit 41 configured as described above detects the voltage (current detection signal) Vis generated at both ends of the current detection resistor Rs by the differential amplifier circuit 42, and reverses the polarity of the signal detected by the differential amplifier circuit 42. And output as a current feedback signal Ifbk. The current feedback signal Ifbk is input to the addition point (node N11) of the regulator circuit 11 via the resistor R13.

Here, the voltage (current detection signal) Vis generated at both ends of the current detection resistor Rs is represented by Is as the current flowing through the piezo element Pz.
Vis = Rs × Is,
It becomes.

The voltage (current detection signal) Vis detected by the current detection resistor Rs is amplified by the differential amplifier circuit 42 in the current feedback circuit 41 and output as the output voltage Vis ′. The output voltage Vis ′ of the differential amplifier circuit 42 is obtained when the resistance value of the resistor R41 and the resistance value of the resistor R42 are equal, and the resistance value of the resistor R43 and the resistance value of the resistor R44 are equal.
Vis ′ = − (R44 / R41) × Vis,
It becomes. In the example shown in FIG. 5, the output voltage Vis ′ of the differential amplifier circuit 42 is a negative signal.

The output voltage Vis ′ of the differential amplifier circuit 42 is input to the inverting amplifier circuit 43. The inverting amplifier circuit 43 inverts and amplifies the output voltage Vis ′ of the differential amplifier circuit 42 to generate a current feedback signal Ifbk.
This current feedback signal Ifbk is
Ifbk = + (R46 / R45) × (R44 / R41) × Vis,
It becomes. In the example shown in FIG. 5, the current feedback signal Ifbk is a + polarity signal.

  FIG. 6 is a diagram showing an example of the waveform of each part in the piezoelectric element driving apparatus 1A shown in FIG. The waveform shown in FIG. 6 indicates the passage of time t in the horizontal direction, and the waveform of the command input Vin, the current Is flowing through the piezo element Pz, the charging voltage Vc1 of the capacitor C1, and the charge amount feedback signal Qfbk in the vertical direction. Are shown side by side. Note that, as shown in FIG. 3C, a negative voltage is applied as the charging voltage Vc1 of the capacitor C1. That is, charging is performed so that the node A side has a positive potential and the node B side has a negative potential.

  Then, as shown in FIG. 6A, the command input Vin input from the outside rises in a step shape at time t0. Thereby, as shown in FIG. 6B, after time t0, the current Is flows from the piezo drive power supply unit 20 to the piezo element Pz and the capacitor C1. Then, as shown in FIG. 6C, after time t0, the charging voltage Vc1 of the capacitor C1 rises smoothly (more precisely, falls smoothly to the negative side). As a result, the waveform of the charging voltage Vc1 of the capacitor C1 indicates the waveform of the charge amount of the capacitor C1, and also indicates the charge amount of the piezo element Pz.

  Then, as shown in FIG. 6D, after time t0, the charge amount feedback signal Qfbk rises smoothly in response to the rise of the charging voltage Vc1 of the capacitor C1. After that, when the charging voltage Vc1 of the capacitor C1 reaches the target value with respect to the command input Vin at time t1, the current Is flowing through the piezo element Pz becomes almost 0 (zero), and the charging operation to the capacitor C1, that is, piezo is performed. The charge charging operation (displacement operation) to the element Pz is completed.

  As described above, the piezoelectric element driving apparatus 1A according to the second embodiment uses the charge amount feedback circuit 31 and the charge amount feedback circuit 31 in combination, so that the voltage Vc of the capacitor C1 can be obtained even when the command input Vin rises stepwise. It is possible to start up smoothly without causing overshoot or undershoot in the waveform. Therefore, the electric charge to the piezo element Pz is smoothly performed.

[Third Embodiment]
FIG. 7 is a block diagram showing a configuration of a piezo element driving device path according to the third embodiment of the present invention.

  The piezo element driving apparatus 1B shown in FIG. 7 is different from the piezo element driving apparatus 1A shown in FIG. 4 in the capacitor C1 (the capacitor connected in series with the piezo element Pz) in the piezo element driving apparatus 1A shown in FIG. C1) and the voltage detection circuit 4 are omitted, and a charge amount calculation circuit 51 is provided instead of the charge amount feedback circuit 31 in terms of configuration.

  This charge amount calculation circuit 51 calculates the charge amount of charge of the virtual capacitor C1 by virtually integrating the detection signal of the current Is flowing through the piezo element Pz, assuming that the capacitor C1 is virtually present. The charge amount feedback signal Qfbk is generated based on the charged amount of charge. The configuration and operation of other circuit portions are the same as those of the piezoelectric element driving apparatus 1A shown in FIG.

As described above, in the piezo element driving apparatus 1 of the first embodiment and the piezo element driving apparatus 1A of the second embodiment, the capacitor C1 is connected in series with the piezo element Pz. When the voltage V1 is applied to the series circuit of the piezo element Pz and the capacitor C1 (between the node A and the node B), the voltage Vpz applied to the piezo element Pz having the capacitance C0 is connected in series. Because it becomes the partial pressure with the capacitor C1,
Vpz = (C1 / (C0 + C1)) × V1,
It becomes.

Therefore, assuming that the full stroke voltage required for driving the piezo element Pz to full stroke is Vmax, the voltage V1 that needs to be output from the piezo drive power supply unit 20 is:
V1 = (1 + C0 / C1) × Vmax,
It becomes.

  Even if a capacitor C1 having the same capacitance as the capacitance C0 of the piezo element Pz is connected in series to the piezo element Pz, the voltage V1 required to be output from the piezo drive power supply unit 20 is the full stroke voltage. A voltage twice as high as Vmax is required. In order to keep the voltage V1 required to be output from the piezo drive power supply unit 20 low, it is necessary to prepare a capacitor C1 having a sufficiently large capacitance. In applications where the piezoelectric element Pz has a large capacitance of several tens of μF and requires a working voltage exceeding 100 V, an electrolytic capacitor or a film capacitor is selected as the capacitor C1 having a high withstand voltage and a large capacity. However, it is necessary to use a film capacitor in consideration of liquid leakage and capacitor life. However, the film capacitor has a larger volume than other types of capacitors with the same capacitance, and when a film capacitor is used, the area occupied by the film capacitor on the substrate increases, or the piezoelectric drive power supply unit As a result, the volume of the piezo element driving device becomes large, which is a major factor that hinders downsizing of the piezoelectric element driving device.

  By the way, in the piezoelectric element driving devices of the first and second embodiments, the charging voltage of the capacitor C1 charged with the same amount of charge as that of the piezoelectric element Pz is applied to resistors R1 and R2 connected in parallel to the capacitor C1. The voltage detection signal Vq is generated by detection by the voltage dividing resistor R2, and the charge amount feedback signal Qfbk is generated by the charge amount feedback circuit 31 based on the voltage detection signal Vq.

Here, assuming that the current flowing through the piezo element Pz and the capacitor C1 is Is, the charge Qc1 charged in the capacitor C1 and the charge Qpz charged in the piezo element Pz are time-integrated with the current Is flowing in the piezo element Pz. This can be calculated. That is, the charge Qc1 charged in the capacitor C1 and the charge Qpz charged in the piezo element Pz are:
Qc1 = Qpz = ∫Isdt,
Can be calculated.

  That is, the charge Qc1 charged in the capacitor C1 and the charge Qpz charged in the piezo element Pz can be calculated by time-integrating the current Is flowing through the piezo element Pz. For this reason, the amount of charge charged in the piezo element Pz may be synthesized by integrating the current Is flowing in the piezo element Pz over time without using the capacitor C1 connected in series to the piezo element Pz. For this reason, in the piezo element driving apparatus 1B of the third embodiment, instead of the capacitor C1, a charge amount calculation circuit 51 is provided, and the charge amount calculation circuit 51 charges the piezo element Pz. Is calculated to generate a charge amount feedback signal Qfbk.

As described above, in the piezo element driving apparatus 1B, the amount of electric charge accumulated in the piezo element Pz is calculated by integrating the current Is flowing in the piezo element Pz with time instead of connecting the capacitor C1 to the piezo element Pz. As a result, the amount of charge accumulated in the piezo element Pz can be detected in the same manner as when the capacitor C1 is connected in series to the piezo element Pz and the voltage is divided and detected.
Thereby, in the piezo element driving apparatus 1B, the large-capacity film capacitor C1 is not required, and the output voltage V1 of the piezo driving power supply unit 20 is directly applied to the piezo element Pz. The output voltage can be reduced. For this reason, in the piezo element driving apparatus 1B, it is possible to reduce the cost and reduce the size.

FIG. 8 is a diagram showing a circuit configuration of the piezo element driving apparatus 1B of the third embodiment, and shows a more specific circuit configuration of the charge amount calculation circuit 51 in the piezo element driving apparatus 1B shown in FIG. FIG. The sign of the polarity (+ or −) shown in the circuit of the piezo element driving device 1B indicates that the current Is flowing from the piezo driving power supply unit 20 to the piezo element Pz is in the illustrated direction (from the node B side to the node A side). The polarity of the signal of each part when flowing toward is shown.
Hereinafter, in the piezo element driving apparatus 1B shown in FIG. 8, only the parts different in configuration from the piezo element driving apparatus 1A of the second embodiment shown in FIG. 5 will be described, and overlapping description will be omitted.

  In the piezo element driving apparatus 1B shown in FIG. 8, the regulator circuit 11 constitutes a PI (proportional / integral) circuit. In response to the command signal Vref (−polar signal), the regulator circuit 11 includes a current feedback signal Ifbk (+ polarity signal) and a charge amount feedback signal Qfbk (+ polarity signal) output from the charge amount calculation circuit 51. ) To obtain an error signal, and a proportional operation and an integration operation are performed on the error signal, and a voltage command signal Vd is generated by the proportional operation and the integration operation.

The charge amount calculation circuit 51 includes an integration circuit 52, a differential amplifier circuit 53, and an inverting amplifier circuit 54.
The integrating circuit 52 is a circuit that time-integrates the detection signal of the current Is flowing through the piezo element Pz, and specifically, a circuit that integrates the output signal Vis ′ of the differential amplifier circuit 42 in the current feedback circuit 41 with a capacitor. It is.
In this integrating circuit 52, one end of the resistor R51 is connected to the negative input terminal of the operational amplifier IC11, and the other end of the resistor R51 is connected to the output terminal of the operational amplifier IC5 in the current feedback circuit 41. Further, the + side input terminal of the operational amplifier IC11 is connected to the circuit ground G. The output terminal of the operational amplifier IC11 is connected to one end of the capacitor C51. The other end of the capacitor C51 is connected to one end of the resistor R52 and to the negative input terminal of the operational amplifier IC11. The other end of the resistor R52 is connected to the circuit ground G. In the integration circuit 52, the current Ib (= Vis ′ / R51) flowing through the resistor R51 is integrated by the capacitor C51 by the input signal Vis ′, and a voltage Vc51 is generated at both ends of the capacitor C51.
Each of the voltages at both ends of the capacitor C51 is input to a voltage follower circuit (impedance conversion circuit) composed of the operational amplifiers 11A and 11B. The + side input terminal of the operational amplifier IC11A is connected to one end of the capacitor C51 and the output terminal of the operational amplifier IC11, and the − side input terminal is connected to the output terminal of the operational amplifier IC11A. The + side input terminal of the operational amplifier IC11B is connected to the other end of the capacitor C51 and one end of the resistor R52, and the − side input terminal is connected to the output terminal of the operational amplifier IC11B.
As a result, the voltage Vc51 generated at both ends of the capacitor C51 is output as it is between the output terminal of the operational amplifier IC11A and the output terminal of the operational amplifier IC11B.

  The differential amplifier circuit 53 is a circuit that amplifies only the potential difference between the two input voltages. Specifically, the differential amplifier circuit 53 amplifies and outputs the voltage Vc51 generated at both ends of the capacitor C51. In the differential amplifier circuit 53, one end of a resistor R53 is connected to the negative input terminal of the operational amplifier IC12, and the other end of the resistor R53 is connected to the output terminal of the operational amplifier IC11A. Further, one end of the resistor R54 is connected to the + side input terminal of the operational amplifier IC12, and the other end of the resistor R54 is connected to the output terminal of the operational amplifier IC11B. One end of the resistor R55 is connected to the + side input terminal of the operational amplifier IC12, and the other end of the resistor R55 is connected to the circuit ground G. A resistor R56 is connected between the negative input terminal and the output terminal of the operational amplifier IC12.

  The inverting amplifier circuit 54 is a circuit that inverts and amplifies the signal output from the differential amplifier circuit 53 to generate a charge amount feedback signal Qfbk. In the inverting amplifier circuit 54, a resistor R58 is connected between the negative input terminal and the output terminal of the operational amplifier IC13, one end of the resistor R57 is connected to the negative input terminal of the operational amplifier IC13, and the other end of the resistor R57 is It is connected to the output terminal of the operational amplifier IC12. The + side input terminal of the operational amplifier IC13 is connected to the circuit ground G.

  The charge amount calculation circuit 51 configured as described above integrates the output signal Vis ′ of the differential amplifier circuit 42 in the current feedback circuit 41 by the capacitor C51, and based on the voltage Vc51 generated in the capacitor C51, the charge amount feedback signal Qfbk. Is generated.

The voltage Vc51 generated in the capacitor C51 of the integrating circuit 52 is
Vc51 = ∫Ibdt,
It becomes. Here, Ib is Ib = Vis ′ / R51.
The voltage Vc51 of the capacitor C51 generated by the integrating circuit 52 is input to the differential amplifier circuit 53 via the operational amplifiers IC11A and 11B, and the voltage Vc51 of the capacitor C51 is amplified by the differential amplifier circuit 53 and output. It is output as voltage Vq ′. The output voltage Vq ′ of the differential amplifier circuit 32 is obtained when the resistance value of the resistor R53 and the resistance value of the resistor R54 are equal, and the resistance value of the resistor R56 and the resistance value of the resistor R55 are equal.

Vq ′ = − (R56 / R53) × Vc51,
It becomes. In the example shown in FIG. 8, the output voltage Vq ′ of the differential amplifier circuit 53 is a negative signal.

The output voltage Vq ′ of the differential amplifier circuit 53 is input to the inverting amplifier circuit 54. The inverting amplifier circuit 54 inverts and amplifies the output voltage Vq ′ of the differential amplifier circuit 53 to generate a charge amount feedback signal Qfbk. .
This charge amount feedback signal Qfbk is
Qfbk = + (R58 / R57) × (R56 / R53) × Vc51,
It becomes. In the example shown in FIG. 8, the charge amount feedback signal Qfbk is a + polarity signal.

As described above, the charge amount calculation circuit 51 time-integrates the detection signal Vis ′ of the current Is flowing through the piezo element Pz, so that there is a virtual capacitor C1. The voltage Vc51) generated by the circuit 52 is calculated, and the charge amount feedback signal Qfbk can be generated based on the calculated charge amount (voltage Vc51).
Thereby, the capacitor C1 used in the first and second embodiments can be omitted, the cost of the piezo element driving device 1B can be reduced, and the size can be reduced.
In the block diagram of FIG. 8, the charge amount calculation circuit 51 may be configured to be able to calculate the charge amount at high speed using a CPU or the like. In this case, for example, the output signal Vis ′ of the current feedback circuit 41 is converted from analog to digital by an A / D converter, and calculation (integration) processing is performed by a CPU to obtain a charge amount feedback signal Qfbk, which is input to the node N11. Can do. Thereby, the capacitor C51 can be omitted.

  Although the embodiments of the present invention have been described above, the piezo element driving devices 1, 1A and 1B of the present embodiment are piezos as actuators in an exposure device (see, for example, Patent Document 2) and a lens driving device of an imaging device. It can be suitably used when the element Pz is used. This lens driving device is, for example, a lens driving device for autofocusing of an imaging device or a lens driving device for camera shake correction.

  In addition, when the lens position is controlled by detecting the lens position with an encoder or the like in the lens driving device, the command is provided by reducing the hysteresis characteristic of the piezo element Pz by using the piezo element driving device of this embodiment. The positional deviation with respect to the input can be reduced, and the responsiveness when moving the lens position to a desired position can be improved.

  Here, as an example of the exposure apparatus, this exposure apparatus is an apparatus having a configuration as shown in FIG. The exposure apparatus 101 shown in FIG. 9 uses the exposure light EL supplied from the light source apparatus 102 to illuminate the reticle R on which a predetermined circuit pattern is formed, and an image of the circuit pattern formed by the illumination is used as a resist or the like. Is an apparatus for projecting onto the exposure surface Wa of the wafer W coated with the photosensitive material. Such an exposure apparatus 101 includes an illumination optical system 103 that illuminates the reticle R with the exposure light EL from the light source device 102, a reticle stage 104 that holds the reticle R, and exposure of the wafer W with the exposure light EL that passes through the reticle R. A projection optical system 105 that irradiates a surface Wa (wafer surface coated with a photosensitive material) and a wafer stage 107 that holds the wafer W are provided.

  In the exposure apparatus 101 having such a configuration, when controlling the position of the lens 106 of the projection optical system 105 (for example, the position in the Z-axis direction), the piezo element 114 can be used as an actuator. Then, by driving the piezo element 114 with the piezo element drive device 1, 1A or 1B of the present embodiment, it becomes possible to reduce the hysteresis characteristic in the piezo element 114 and to control the position of the lens with high accuracy. .

  In the exposure apparatus 101 shown in FIG. 9, the position detection sensor 111 detects the position of the lens 106. The position control unit 112 detects the position of the lens 106 based on the position detection signal of the lens 106 detected by the position detection sensor 111. The piezo element 114 is driven via the piezo element driving device 113 so as to move the position to the target position. In this case, by using the piezo element driving device 1 of this embodiment as the piezo element driving device 113, the hysteresis characteristic of the piezo element Pz is reduced, the positional deviation with respect to the applied voltage is reduced, and the response of the control system is improved. Is done. Further, even when the position of the lens 106 is moved to the target position without detecting the position of the lens 106 by the position detection sensor 111, the piezoelectric element Pz of the piezo element Pz can be obtained by using the piezoelectric element driving device 1 or the like of this embodiment. The hysteresis characteristic is reduced, and the lens 106 can be moved to the target position with high accuracy.

  The exposure apparatus 101 may control the tilt of the lens 106. In this case, the tilt of the lens 106 is increased by driving the piezo element Pz using the piezo element driving apparatus 1 of this embodiment. It can be controlled with accuracy.

Further, the position of the reticle stage 104 that holds the reticle R can also be controlled by using the piezo element 115 as an actuator. When driving the reticle stage 104, the hysteresis characteristic of the piezoelectric element 115 is reduced by driving the piezoelectric element 115 by the piezoelectric element driving apparatus 1 or the like of the present embodiment, and the position of the reticle R (for example, X, Y , The position in the Z-axis direction) can be moved to the target position with high accuracy. The same applies to the case where the piezo element Pz is used as an actuator for moving the wafer stage 107.
As described above, when the piezo element Pz is used to drive the lens 106 of the exposure apparatus 101 and the stage such as the reticle stage 104 and the wafer stage 107, the piezo element Pz is used as the piezo element driving apparatus 1 of the present embodiment. By driving using 1A or 1B, the hysteresis characteristic of the piezo element Pz is reduced, and the lens and the stage can be moved to the target position with high accuracy.

Here, the correspondence between the present invention and the above embodiment will be described supplementarily. In the above embodiment, the electrostrictive element driving device according to the present invention corresponds to the piezo element driving device 1, the piezo element driving device 1A, or the piezo element driving device 1B, and the electrostrictive element according to the present invention corresponds to the piezo element Pz. In addition, the electrostrictive element drive power supply unit in the present invention corresponds to the piezo drive power supply unit 20, and the control unit in the present invention corresponds to the control unit 3. The charge detection unit in the present invention corresponds to the voltage detection circuit 4, which indirectly detects the charge amount of the piezo element Pz by detecting the charge voltage of the capacitor C1. . The voltage control circuit in the present invention corresponds to the regulator circuit 11.
The current detection circuit in the present invention corresponds to the current detection resistor Rs. The command signal in the present invention corresponds to a command input Vin (more precisely, a command signal Vref buffered by inverting the voltage of the command input Vin). The charge amount feedback signal in the present invention corresponds to the charge amount feedback signal Qfbk, and the current feedback signal in the present invention corresponds to the current feedback signal Ifbk.

(1) In the above-described embodiment, the piezo element driving device 1 outputs a DC voltage applied to the piezo element Pz, and variably controls the magnitude of the output voltage, and the piezo driving power source. A voltage detection circuit 4 for detecting the charge amount of the piezo element Pz charged by the unit 20, an externally input command input Vin, and a detection signal Vq of the charge amount of the piezo element Pz detected by the voltage detection circuit 4. And a control unit 3 that controls the piezo drive power supply unit 20 so that the charge amount of the piezo element Pz is set to a value corresponding to the command input Vin. The control unit 3 is externally input. The amount of displacement of the piezo element Pz is controlled by charging the piezo element Pz with a charge amount corresponding to the command input Vin.
In the piezo element driving apparatus 1 having such a configuration, the displacement amount of the piezo element Pz is controlled in accordance with the command input Vin input from the host side (external). The piezo element driving device 1 detects the charge amount of the piezo element Pz when applying a DC voltage to the piezo element Pz and displaces it, and this charge amount detection signal (charge amount feedback signal Qfbk)) The command input Vin is compared, and control is performed so that the charge amount of the piezo element Pz is set to a value corresponding to the command input Vin.
Thereby, the piezo element driving device 1 can control the charge amount of the piezo element Pz even when the capacitance of the piezo element Pz changes due to the hysteresis characteristic of the piezo element Pz. Hysteresis characteristics can be reduced.

(2) In the above embodiment, in the piezo element driving device 1, the piezo element Pz is connected to the capacitor C1 in series with the piezo element Pz, and the piezo drive power supply unit 20 is connected to the piezo element Pz via the capacitor C1. The voltage detection circuit 4 detects the charge voltage of the piezo element Pz by detecting the charge voltage of the capacitor C1, and the control unit 3 sets the capacitor C1 at a voltage corresponding to the command input Vin input from the outside. By charging, the charge amount of the piezo element Pz is controlled.
In the piezoelectric element driving apparatus 1 having such a configuration, the capacitor C1 is connected in series to the piezoelectric element Pz. The piezo drive power supply unit 20 charges the piezo element Pz via the capacitor C1, and the voltage detection circuit 4 indirectly detects the charge amount of the piezo element Pz by detecting the charge voltage of the capacitor C1. That is, the charge amount of the capacitor C1 is determined by the charge voltage of the capacitor C1, and since the charge amount of the capacitor C1 and the charge amount of the piezo element Pz are the same, the charge voltage of the capacitor C1 is detected. By doing so, the charge amount of the piezo element Pz can be detected. The controller 3 controls the charge amount of the piezo element Pz by charging the capacitor with a voltage corresponding to the command input Vin input from the outside.
Thereby, the piezo element driving apparatus 1 can control the charge voltage of the capacitor C1 connected in series to the piezo element Pz to control the charge amount of the piezo element Pz to a desired value. . Therefore, even when the capacitance of the piezo element Pz changes due to the hysteresis characteristic of the piezo element Pz, the charge amount of the piezo element Pz can be controlled to a desired value. For this reason, the hysteresis characteristic of the piezo element Pz can be reduced.

(3) In the above embodiment, the piezoelectric element driving apparatus 1 uses the voltage detection circuit 4 that detects the charging voltage of the capacitor C1 and the detection signal Vq of the charging voltage of the capacitor C1 that is detected by the voltage detection circuit 4. The command input Vin and the charge amount feedback signal Qfbk are set to a predetermined value using the charge amount feedback circuit 31 that generates the charge signal feedback signal Qfbk of the piezo element Pz, the command input Vin and the charge amount feedback signal Qfbk. And a regulator circuit 11 that controls the output voltage of the piezo drive power supply unit 20 so as to be in a state.
In the piezo element driving apparatus 1 having such a configuration, the charging voltage of the capacitor C1 is detected, and the charge amount feedback signal Qfbk is generated based on the detection signal Vq. Then, the regulator circuit 11 compares the command input Vin and the charge amount feedback signal Qfbk, and controls the output voltage V1 of the piezo drive power supply unit 20 so that the command input Vin and the charge amount feedback signal Qfbk match.
Thereby, the piezo element driving apparatus 1 can control the piezo drive power supply unit 20 so that the command input Vin input from the outside matches the feedback signal Qfbk of the charge amount of charge of the piezo element Pz. For this reason, the piezo element driving device 1 can control the charge amount of the piezo element Pz in accordance with the command input Vin.

(4) In the above embodiment, the piezo element driving apparatus 1A uses the current detection resistor Rs for detecting the current Is flowing through the piezo element Pz and the current detection signal Vis detected by the current detection resistor Rs for current feedback. And a current feedback circuit 41 that generates a signal Ifbk. The regulator circuit 11 uses two signals of the charge amount feedback signal Qfbk and the current feedback signal Ifbk as feedback signals, and the two feedback signals and the command input Vin The output voltage of the piezo drive power supply unit 20 is controlled using the difference.
In the piezoelectric element driving apparatus 1A having such a configuration, in addition to the feedback circuit 31 for the charge amount of the piezoelectric element Pz, a feedback circuit 41 for the current Is flowing through the piezoelectric element Pz is further provided.
Thereby, the piezo element driving apparatus 1A can control the current flowing through the piezo element Pz, and can improve the responsiveness when charging the piezo element Pz.

(5) In the above embodiment, the voltage detection circuit 4 has a resistance voltage dividing circuit (resistor R1 and resistor R2) connected in parallel to the capacitor C1, and the charge amount feedback circuit 31 is a resistance voltage dividing circuit. A differential amplifier circuit 32 that detects the voltage across one resistor R2 included therein, and the current detection circuit uses a current detection resistor Rs inserted between the piezo element Pz and the piezo drive power supply unit 20. The current feedback circuit 41 includes a differential amplifier circuit 42 that detects the voltage Vis across the current detection resistor Rs, and the regulator circuit 11 includes a proportional integration circuit.
In the piezoelectric element driving device 1 or 1A having such a configuration, the charging voltage of the capacitor C1 can be easily detected using the voltage dividing resistor R2 and the differential amplifier circuit 32. Further, the current Is flowing through the piezo element Pz can be easily detected using the current detection resistor Rs and the differential amplifier circuit 42. Further, by configuring the regulator circuit 11 with a PI (proportional / integral) circuit, the charge amount of the piezo element Pz (more precisely, the charge voltage of the capacitor C1) has a steady deviation with respect to the command input Vin. Can be controlled accurately without any problem. Further, the constant of the proportional element (resistor R14) and the constant of the integral element (capacitor C11) can be set to desired values according to the transfer functions of the circuit system and the actuator mechanism system, and the piezo element Pz can be stabilized. Can be driven.

(6) In the above embodiment, the piezo element driving device 1B uses the current detection resistor Rs for detecting the current Is flowing in the piezo element Pz and the current feedback signal using the current detection signal detected by the current detection resistor Rs. The current feedback circuit 41 that generates Ifbk and the charge detection amount of the piezo element Pz are calculated by time integration of the current detection signal detected by the current detection resistor Rs, and the piezo element is calculated based on the calculated charge charge amount. The charge amount calculation circuit 51 that generates the feedback signal Qfbk of the charge amount of Pz, and the two signals of the charge amount feedback signal Qfbk and the current feedback signal Ifbk generated by the charge amount calculation circuit 51 are used as feedback signals. Piezo drive using the difference between the signal and the command input Vin It includes a regulator circuit 11 for controlling the output voltage of the power supply unit 20, a.
The piezo element driving apparatus 1B having such a configuration calculates the amount of charge accumulated in the piezo element Pz by integrating the current Is flowing through the piezo element Pz with time instead of connecting the capacitor C1 to the piezo element Pz. . Thereby, in the piezo element driving apparatus 1B, the amount of charge accumulated in the piezo element Pz can be detected in the same manner as the case where the capacitor C1 is connected in series to the piezo element Pz and the voltage is divided and detected. it can.
Therefore, in the piezoelectric element driving apparatus 1B, the large-capacity film capacitor C1 is not necessary, and the output voltage V1 of the piezoelectric driving power supply unit 20 is applied as it is, so that the output voltage of the piezoelectric driving power supply unit 20 is changed. Can be reduced. For this reason, in the piezo element driving apparatus 1B, the cost can be reduced and the apparatus can be downsized.

(7) In the above embodiment, the electrostrictive element is a piezo element.
Thereby, in the piezoelectric element driving devices 1, 1A and 1B, even when the capacitance of the piezoelectric element Pz changes due to the hysteresis characteristic of the piezoelectric element Pz, the charge amount of the piezoelectric element Pz becomes a desired value. And the hysteresis characteristic of the piezo element Pz can be reduced.

(8) In the above-described embodiment, the exposure apparatus 101 includes the piezo element driving apparatus 1 described above, and the piezo element Pz is driven by using the piezo element driving apparatus 1, thereby exposing the exposure apparatus. The lens position or stage position of the internal optical system is moved.
Accordingly, when the stage position of the reticle stage 104 or the like in the exposure apparatus 101 or the position of the lens 106 is moved by the piezo element Pz, variation in the amount of displacement due to the hysteresis characteristic of the piezo element Pz can be reduced.

(9) In the above-described embodiment, the lens driving device includes the piezo element driving device 1 described above, and the piezo element Pz is driven by using the piezo element driving device 1 to thereby form an optical system. Move the lens position.
Thus, the piezo element Pz is driven using the piezo element driving apparatus 1 of the present embodiment in a camera lens driving apparatus, for example, an autofocus lens driving apparatus or a camera shake correction lens driving apparatus. As a result, variation in displacement due to the hysteresis characteristics of the piezo element Pz can be reduced.

Although the embodiments of the present invention have been described above, the electrostrictive element driving device of the present invention is not limited to the above-described piezoelectric element driving devices 1, 1A and 1B, and does not depart from the gist of the present invention. Of course, various changes can be made within the range.
For example, the electrostrictive element that can be driven by the electrostrictive element driving device of the present invention is not limited to a piezo element, but is a capacitive element, and all the displacements exhibit hysteresis characteristics with respect to the applied voltage. This element is the target.

DESCRIPTION OF SYMBOLS 1,1A, 1B ... Piezo element drive device, 2 ... Piezo element Pz, 3 ... Control part, 4 ... Voltage detection circuit, 10 ... Command signal generation circuit, 11 ... Regulator circuit, 20 ... Piezo drive power supply part, 20A ... PWM Control unit, 21 ... smoothing circuit, 31 ... charge amount feedback circuit, 32 ... differential amplifier circuit, 33 ... inverting amplifier circuit, 41 ... current feedback circuit, 42 ... differential amplifier circuit, 43 ... inverting amplifier circuit, 51 ... charge Quantity calculation circuit 52 ... Integral circuit 53 ... Differential amplifier circuit 54 ... Inverting amplifier circuit C1 ... Capacitor R1, R2 ... Resistance Rs ... Current detection resistor 101 ... Exposure device 104 ... Reticle stage 106 ... Lens 107: Wafer stage 113 ... Piezo element driving device 114, 115 ... Piezo element

Claims (9)

An electrostrictive element drive power supply unit that can output a DC voltage applied to the electrostrictive element and variably control the magnitude of the voltage;
A charge amount detector for detecting a charge amount of an electrostrictive element charged by the electrostrictive element drive power supply unit;
Using a command signal input externally and a detection signal of the charge amount of the electrostrictive element detected by the charge amount detection unit, the charge amount of the electrostrictive element is a value corresponding to the command signal. A control unit for controlling the electrostrictive element drive power supply unit to be set to,
The electrostrictive element driving apparatus, wherein the control unit controls the amount of displacement of the electrostrictive element by charging the electrostrictive element with an amount of charge corresponding to the command signal input from the outside. A capacitor is connected to the electrostrictive element in series with the electrostrictive element,
The electrostrictive element drive power supply unit charges the electrostrictive element via the capacitor,
The charge amount detector detects a charge amount of the electrostrictive element by detecting a charge voltage of the capacitor,
2. The electrostrictive element according to claim 1, wherein the control unit controls a charge amount of the electrostrictive element by charging the capacitor with a voltage corresponding to the command signal input from the outside. Drive device. A voltage detection circuit for detecting a charging voltage of the capacitor;
A charge amount feedback circuit that generates a feedback signal of the charge amount of charge of the electrostrictive element using a voltage detection signal of the charge voltage of the capacitor detected by the voltage detection circuit;
Using the command signal and the charge amount feedback signal, a voltage control circuit that controls an output voltage of the electrostrictive element drive power supply unit so that the command signal and the charge amount feedback signal are in a predetermined state;
The electrostrictive element driving device according to claim 2, comprising: A current detection circuit for detecting a current flowing through the electrostrictive element;
A current feedback circuit that generates a current feedback signal using a current detection signal detected by the current detection circuit; and
The voltage control circuit uses two signals of the charge amount feedback signal and the current feedback signal as feedback signals, and uses the difference between the two feedback signals and the command signal to output voltage of the electrostrictive element driving power supply unit. The electrostrictive element driving device according to claim 3, wherein the electrostrictive element driving device is controlled. The voltage detection circuit has a resistance voltage dividing circuit connected in parallel to the capacitor,
The charge amount feedback circuit includes a differential amplifier circuit that detects a voltage across one resistor included in the resistor voltage divider circuit;
The current detection circuit is configured using a current detection resistor inserted between the electrostrictive element and the electrostrictive element driving power supply circuit,
The current feedback circuit includes a differential amplifier circuit that detects a voltage across the current detection resistor,
The electrostrictive element driving device according to claim 4, wherein the voltage control circuit includes a proportional integration circuit. A current detection circuit for detecting a current flowing through the electrostrictive element;
A current feedback circuit that generates a current feedback signal using a current detection signal detected by the current detection circuit;
The charge detection amount of the electrostrictive element is calculated by time integration of the current detection signal detected by the current detection circuit, and a feedback signal of the charge amount of the electrostrictive element is calculated based on the calculated charge amount. A charge amount calculation circuit to be generated;
Two signals of the charge amount feedback signal and the current feedback signal generated by the charge amount calculation circuit are used as feedback signals, and the difference between the two feedback signals and the command signal is used for the electrostrictive element drive power supply unit. A voltage control circuit for controlling the output voltage;
The electrostrictive element driving device according to claim 1, comprising:   The electrostrictive element driving apparatus according to claim 1, wherein the electrostrictive element is a piezo element.   An electrostrictive element driving apparatus according to claim 1 is provided, and the electrostrictive element is driven by using the electrostrictive element driving apparatus to move the lens position or stage position of the optical system. An exposure apparatus characterized by that.   An electrostrictive element driving device according to claim 1 is provided, and the electrostrictive element is driven by using the electrostrictive element driving device to move the lens position of the optical system. A lens driving device.

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