JP2009152557A - Piezoelectric actuator with displacement meter and piezoelectric element, and positioning apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric actuator with a displacement meter, which allows distortion of a piezoelectric element to be accurately measured by a resistor attached to the piezoelectric element without being affected by a capacitance component and is free from faults due to short circuit to thereby have a high reliability, and to provide a piezoelectric element and a positioning apparatus using the same. <P>SOLUTION: The piezoelectric actuator comprises: the piezoelectric element 1 which is formed into an optional shape and has internal ions subjected to polarization processing in an optional direction and is provided with electrodes 2a, 2b, 3b, 4b and 5b in at least two surfaces facing each other in a thickness direction; driving power sources 9, 10 and 11 which apply voltages between electrodes to generate distortion on the piezoelectric element 1; resistors Rz3, Rx1, Rx2 and Ry2 provided on an electrode 7 through an insulator; and displacement detectors 12, 13 and 14 which are connected to the resistors and detect the amount of distortion of the piezoelectric element 1 by applying optional voltages to the resistors to detect resistance value changes. The electrode 7 on the piezoelectric element 1, where the resistors are provided, is connected to a ground potential. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a piezoelectric actuator used for a positioning device of a precision instrument, and is applied to, for example, a scanner for a scanning probe microscope.

Conventionally, piezoelectric actuators are used in various precision instruments such as measuring devices as precision positioning devices on the order of sub-nanometers to several hundreds of micrometers.
Here, a positioning device using a piezoelectric actuator will be described by taking a scanning probe microscope as an example (see Patent Document 1).

  FIG. 22 is a block diagram of a conventional scanning probe microscope. In a conventional scanning probe microscope, a cantilever 214 having a probe 213 at the tip, a sample holder 211 placed at a position facing the probe 213 and on which a sample 212 is placed, and the probe 213 within the sample plane It comprises a three-axis fine movement mechanism 215 comprising a horizontal fine movement mechanism to be moved, a vertical fine movement mechanism to be moved in a direction perpendicular to the sample surface, and a displacement detection mechanism 219 for detecting the deflection of the cantilever 214.

  In the prior art of FIG. 22, the triaxial fine movement mechanism 215 uses a piezoelectric actuator using a cylindrical piezoelectric element. The cylindrical piezoelectric element is subjected to polarization treatment so that the inner crystal is in a uniform direction from the inner peripheral surface to the outer peripheral surface in a direction perpendicular to the central axis of the cylinder. A single common electrode 232 is formed on the inner peripheral surface of the cylindrical piezoelectric element, a strip electrode portion 235 provided along the circumference on the outer peripheral surface, and a central axis divided into four with respect to the circumference. Quadrant electrode portions 233 and 234 are provided in parallel directions. If the side on which the strip electrode part 235 is provided is the tip and the side on which the quadrant electrode parts 233 and 234 are provided is the end, a cantilever 214 is attached to the end and the end is fixed to a base (not shown). .

  In the cylindrical piezoelectric actuator, the four divided electrode portions 233 and 234 act as a horizontal fine movement mechanism, and the strip electrode portion 235 acts as a vertical fine movement mechanism. When driving the cylindrical piezoelectric actuator, the common electrode 232 on the inner peripheral surface is connected to the ground potential, and the voltages of opposite phases are respectively applied between the two electrodes facing the central axis of the four-divided electrode portions 233 and 234. Is applied. At this time, one electrode side extends in a direction parallel to the central axis, and the other electrode side contracts. As a result, deflection occurs in the cylindrical piezoelectric element, and the tip performs an arc motion. Here, since the amount of movement of the arc motion is very small, the probe 213 can be moved substantially parallel to the surface of the sample 212. By performing the same operation between the other two opposing electrodes, the probe 213 can be moved two-dimensionally within the surface of the sample 212.

  In addition, when a voltage is applied to the strip-shaped electrode portion 235 on the outer peripheral surface, distortion occurs in the diameter direction, and as a result, distortion occurs in a direction parallel to the central axis, and the probe 213 is moved in a direction orthogonal to the sample 212. It can be moved.

  As a displacement detection mechanism of the cantilever 214, an optical lever method is generally used. The displacement detection mechanism 219 includes a semiconductor laser 216, a condenser lens 217, and a photodetector 218. The light of the semiconductor laser 216 is condensed on the back surface of the cantilever 214 by the condenser lens 217, and the light reflected by the back surface of the cantilever 214 is detected by the photodetector 218. When the deflection of the cantilever 214 occurs, the position of the spot on the photodetector 218 changes, so that the deflection of the cantilever 214 can be detected by detecting the amount of change.

  When the probe 213 and the sample 212 are brought close to each other in the scanning probe microscope configured as described above, an interatomic force or a contact force acts, and the cantilever 214 is bent. At this time, since the deflection amount depends on the distance between the probe 213 and the sample 212, the deflection amount is detected by the displacement detection mechanism 219 of the cantilever 214, and the vertical fine movement mechanism is controlled by the control circuit 221 so that the deflection amount becomes constant. , And by performing a feedback control so that the distance between the probe 213 and the sample 212 is constant, the scanning circuit 222 performs raster scanning of the fine movement mechanism in the horizontal direction, thereby measuring the concavo-convex image on the sample surface. Can do. In addition to the contact method for detecting the static deflection of the cantilever 214, the cantilever 214 is oscillated in the vicinity of the resonance frequency, and the amplitude, phase, or frequency change due to the atomic force or intermittent contact force is searched. In some cases, measurement is performed by a vibration method in which the distance between the needle 213 and the sample 212 is controlled.

  Here, since the three fine movement mechanism 215 used as a positioning device of the scanning probe microscope is composed of a piezoelectric element, hysteresis and creep occur. Hysteresis is a phenomenon in which when a voltage is applied to a piezoelectric element, the displacement does not become completely linear with respect to the voltage, but an operation that approximates a quadratic curve. Creep is a phenomenon in which, when a certain voltage is applied to the piezoelectric element, the target movement amount is not reached immediately, and the minute movement is performed little by little over time.

  When these hysteresis and creep occur, it becomes difficult to perform accurate positioning. Therefore, the displacement of the positioning device is detected by using a displacement detection device for detecting the displacement of the piezoelectric element as a more precise positioning means. A method of detecting hysteresis and compensating for hysteresis and creep is used.

  Various methods such as an optical sensor, a capacitance sensor, and a magnetic sensor are used for the displacement detection device of the piezoelectric element. However, it uses a strain gauge as an inexpensive and simple method that takes up the least space. It is valid.

  FIG. 23 shows a piezoelectric actuator with a displacement meter that detects the displacement of the triaxial fine movement mechanism of a scanning probe microscope of the prior art using a strain gauge. In this prior art, strain gauges 201 a, 201 b, 202 a, 202 b are bonded to the four divided electrode portions 233, 234 on the outer peripheral surface of the cylindrical piezoelectric element 215 one by one for each electrode. In addition, two strain gauges 203a and 203b are bonded to the strip electrode portion 235 in parallel to the central axis. The strain gauge is generally a strain gauge that is commercially available, and is bonded in a direction in which a large output can be obtained when strain occurs in a direction parallel to the central axis of the cylindrical piezoelectric element. In general strain gauges, insulating materials such as polyimide resin, paper, phenol resin, epoxy resin, and phenol / epoxy mixed resin are used for the base material, and metal materials such as copper nickel alloys and nichrome alloys are used on the base material. A resistor composed of a semiconductor such as silicon single crystal is provided, and is electrically connected to an external detection device via an electrode pattern such as nickel formed on the base material.

  In the horizontal fine movement mechanism, a bridge circuit as shown in FIG. 24 is formed by two strain gauges 201a, 201b, 202a, 202b attached to two opposing electrodes 233, 234 and two fixed resistors 241,242. In rare cases, the bridge voltage e0 is applied to the bridge circuit, and the output voltage e1 is measured. When distortion occurs in the piezoelectric element, the resistance values of the strain gauges 201a, 201b, 202a, and 202b change, and the value of the output voltage e1 changes. By detecting this output voltage e1, the amount of distortion of the piezoelectric element can be measured. In this prior art, since the two gauges 201a, 201b, 202a, 202b are bonded to the electrodes 233, 234 facing the central axis, the horizontal fine movement mechanism bends with respect to the central axis. Since the direction of each strain is reversed, the sign of the detection signal of each strain gauge is also reversed, and an output voltage twice that obtained when a strain gauge is attached to only one electrode can be obtained. The signal strength against noise increases. Further, the resistance value change accompanying the temperature change is canceled out, and the temperature compensation is also performed.

  In the case of the vertical fine movement mechanism, a bridge circuit is assembled as shown in FIG. 25 by using two strain gauges 203a and 203b and two fixed resistors 241 and 242, and a bridge voltage e0 is applied to the bridge circuit. Measure e1. When distortion occurs in the piezoelectric element, the resistance value of the strain gauge changes and the value of the output voltage e1 changes. By detecting this output voltage e1, the amount of distortion of the piezoelectric element can be measured. Also in this case, it is possible to obtain an output voltage twice that of a single cage. However, this circuit does not compensate for the resistance value change accompanying the temperature change.

  The output of the strain gauge is obtained by calibrating the displacement and the output voltage e1 from data obtained by measuring a calibration sample with another displacement meter whose displacement is calibrated in advance or a scanning probe microscope using this triaxial fine movement mechanism. The displacement amount can be measured from the output voltage e1 obtained.

Thus, feedback control is performed so that the three-axis fine movement mechanism linearly operates with respect to the applied voltage from the displacement information measured as needed from the output voltage of the strain gauge. In the scanning probe microscope, it is not always necessary to perform a linear operation with respect to the voltage in the vertical direction, and the height information obtained from the output signal of the strain gauge may be displayed as it is.
JP-A-9-89913

  However, in the conventional piezoelectric actuator configured as described above, since the strain gauge is directly bonded to the electrode surface to which the drive voltage of the piezoelectric element is applied via an insulator, the electrode surface of the piezoelectric element and the strain gauge are The insulator is sandwiched between the resistor and the resistor connecting electrode connected to the resistor. Since the base material acts as a dielectric, the portion where the strain gauge is attached acts as if it were a capacitor, generating a capacitance component, and the strain gauge detection signal can be accurately measured due to the influence of this capacitance component. It will disappear.

In addition, since a high voltage for driving the piezoelectric element is applied to the electrode surface of the piezoelectric element, the lead wire connected to the strain gauge contacts the electrode associated with the piezoelectric element, or the strain gauge base material changes over time. A strain gauge electrode or resistor and a piezoelectric element electrode are connected to each other through the inside, and a high voltage is applied to the displacement detection device connected to the strain gauge or the strain gauge, which may damage these devices. In addition, when the insulation resistance of the base material is low, the strain gauge detection signal may not be accurately measured due to the leakage current.
Therefore, the object of the present invention is to measure the distortion of the piezoelectric element with high accuracy without being affected by the capacitance component and the leakage current by the resistor attached to the piezoelectric element, and further, without causing a failure due to a short circuit, reliability. It is to provide a piezoelectric actuator with a high displacement meter, a piezoelectric element, and a positioning device using the same.

  The present invention provides the following means in order to solve the above problems.

  In the present invention, a piezoelectric element is formed in an arbitrary shape, the inner crystal is polarized in an arbitrary direction, and electrodes are provided on at least two opposing surfaces in the thickness direction, and a voltage is applied between the electrodes. A driving power source for applying distortion to the piezoelectric element, a resistor provided on the electrode via an insulator, connected to the resistor, and applying an arbitrary voltage to the resistor, In a piezoelectric actuator with a displacement meter configured by a displacement detection device that detects the amount of strain of the piezoelectric element by detecting a change in resistance value, an electrode on the piezoelectric element provided with a resistor is connected to a ground potential.

  In the present invention, the potential of the electrode on the piezoelectric element provided with the resistor of the piezoelectric actuator with a displacement meter is made equal to the potential applied to the resistor.

In addition, the piezoelectric element used in the piezoelectric actuator with a displacement meter of the present invention is formed in a cylindrical shape, and electrodes are provided on both the inner peripheral surface and the outer peripheral surface of the cylindrical piezoelectric element. In this configuration, a resistor is provided via an insulator. This cylindrical piezoelectric element has a single band-shaped electrode in which the electrode on the inner peripheral surface is divided into a plurality and the electrode on the outer peripheral surface is provided along the outer periphery, or a folded electrode connected to the inner peripheral surface and a single band-shaped It was constituted by an electrode, and a resistor was provided on the belt-like electrode on the outer peripheral surface via an insulator.
In addition, at least two electrodes are provided on the inner peripheral surface of the cylindrical piezoelectric element, and an electrode is also provided on the outer peripheral surface facing the inner peripheral electrode via the piezoelectric body. At least one electrode is a dummy electrode that does not cause distortion, and the other electrode is an active electrode that causes distortion in the piezoelectric element by applying a voltage, and one or two resistors are provided on the outer electrode of the active electrode. The outer electrode of the dummy electrode is provided with one or two resistors, and at least the electrode provided with the resistor is configured to have the same potential and connected to the ground potential, and the outer peripheral surface side of the active electrode When the strain detection is performed by the resistor provided on the outer surface of the dummy electrode, the temperature compensation is performed by the resistor provided on the outer peripheral surface side of the dummy electrode. To constitute a bridge circuit by connecting the antibody.
Further, the piezoelectric element having the dummy electrode and the piezoelectric element having the active electrode are separately formed using the same piezoelectric material.
In addition, after forming an electrode on the surface of the piezoelectric body of the cylindrical piezoelectric element, an electrode on the outer peripheral surface and / or the inner peripheral surface was produced by a method including a step of removing a part of the electrode by machining.
Furthermore, an electrode on the outer peripheral surface and / or the inner peripheral surface was produced by a method including a step of masking the surface of the piezoelectric body, a step of providing an electrode in a portion other than the masking, and a step of removing the mask.

  Furthermore, the piezoelectric element used in the piezoelectric actuator with a displacement meter according to the present invention has a plate-like piezoelectric element fixed to the upper surface and / or the lower surface of an arbitrary plate-like elastic body. An electrode is provided on each of the interfaces, and a bimorph type or unimorph type structure in which a resistor is provided on the surface side electrode of the piezoelectric element via an insulator.

  Furthermore, the piezoelectric element used in the piezoelectric actuator with a displacement meter according to the present invention forms a laminated piezoelectric element by alternately laminating a plurality of film-shaped piezoelectric elements and electrodes, and is sandwiched between the film-shaped piezoelectric elements. Two electrodes that are alternately connected to the stacked electrodes are formed on the side surface of the multilayer piezoelectric element, and a multilayer structure is provided in which a resistor is provided on one electrode of the side electrode via an insulator.

  In the present invention, the piezoelectric element is formed in an arbitrary shape, the inner crystal is polarized in an arbitrary direction, and electrodes are provided on at least two opposing surfaces in the thickness direction, and between the electrodes. A drive power supply for applying a voltage to generate distortion in the piezoelectric element, a resistor provided on the piezoelectric element, and a distortion of the piezoelectric body connected to the resistor and detecting a change in resistance value In a piezoelectric actuator with a displacement meter constituted by a displacement detection device that detects the amount, an electrode is not provided on the piezoelectric element in the portion where the resistor is provided.

  Moreover, the resistor used for the piezoelectric actuator with a displacement meter of this invention used the semiconductor.

  In the present invention, the positioning device is configured using the piezoelectric actuator with a displacement meter configured as described above.

  Since the electrode portion on the piezoelectric element provided with the resistor is connected to the ground electrode or has the same potential as the voltage applied to the resistor, even the resistor configured on the base sheet of the insulator, Since there is almost no potential difference between the electrode surface of the piezoelectric element and the resistor or the resistor connecting electrode connected to the resistor, almost no capacitance component is generated even when the piezoelectric element is driven by applying a high voltage. In other words, the resistance change detection signal is not affected by the capacitance. Further, even when the insulation resistance of the base material is low, almost no leakage current flows. Therefore, it becomes possible to accurately measure the distortion amount of the piezoelectric body, and the detection accuracy of the displacement of the piezoelectric actuator is greatly improved. As a result, the movement accuracy of the positioning device using the piezoelectric actuator is greatly improved.

  Furthermore, the resistance on the insulator connected to the resistor through the contact of the resistor and the electrode attached to the piezoelectric element of the lead wire connected to the resistor, or the inside of the insulator provided with the resistor due to change over time The phenomenon (migration) that the electrode for the body connection or the resistor and the electrode of the piezoelectric element are not connected (migration) does not occur, and it is possible to prevent the resistor and the detection device from being damaged by the short circuit, and the reliability and durability are improved. To do.

    Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  1 to 3 show a piezoelectric actuator with a displacement meter according to a first embodiment of the present invention. FIG. 1 is an overview of a piezoelectric actuator with a displacement meter, FIG. 2 (a) is a development view of the inner peripheral surface of the cylindrical piezoelectric element used in FIG. 1, and FIG. 2 (b) is a development view of the outer peripheral surface. is there.

  In this embodiment, a cylindrical piezoelectric element as shown in FIG. 1 is used. As shown in FIG. 2A, the cylindrical piezoelectric element 1 is provided with a strip-like electrode 2a uniformly along the circumference at the upper part of the inner peripheral surface, and the lower half is divided into four along the circumference. There are provided four-divided electrode portions (3a, 4a, 5a, 6a) formed in a direction parallel to the central axis of the cylinder. Further, as shown in FIG. 2 (b), a folded electrode portion 2b connected to the belt-like electrode portion 2a on the inner peripheral surface is provided at the upper end portion of the outer peripheral surface, and a four-part electrode portion (3a, 4a, 5a, and 6a) are provided with folded electrode portions (3b, 4b, 5b, and 6b), and a single strip electrode 7 is formed along the circumference in a portion other than the folded electrodes.

The total length of the cylindrical piezoelectric element 1 is 100 mm, the outer diameter is 15 mm, the thickness between the inner circumference and the outer circumference is 1 mm, the length of the four divided electrode portions (3a, 4a, 5a, 6a) is 50 mm, and the strip electrode portion The length of 2a is 45 mm. The cylindrical piezoelectric element 1 is polarized so that the inner crystal has a polarity in a direction orthogonal to the central axis of the cylinder from the inner peripheral surface to the outer peripheral surface. The polarity of polarization differs depending on the divided electrode surface on the inner peripheral surface, and has the polarity indicated by the reference numeral in FIG. Here, a plus sign is a portion where the band-like electrode portion 7 on the outer peripheral surface is set to the ground potential and a positive voltage is applied to the inner peripheral surface when polarization is performed, and the crystal inside the element is Negative polarity faces the inner surface. The electrode thus polarized is called a positive electrode. Also, the minus sign is a portion where the strip electrode portion 7 on the outer peripheral surface is set to the ground potential and a negative voltage is applied to the inner peripheral surface when polarization is performed, and the crystal inside the element is positive. The polarity is facing the inner circumference. The electrode thus polarized is called a negative electrode. All the designations of the polarity of electrodes in this specification shall follow this definition. In the cylindrical piezoelectric element 1 of the present embodiment, the belt-like electrode portion 2a on the inner peripheral surface is a plus electrode, and the four-divided electrode portions (3a, 4a, 5a, 6a) are electrodes (3a) facing each other with respect to the central axis. 4a) and (5a, 6a) were subjected to polarization treatment so as to have opposite polarities.
The side on which the strip electrode portion 2a on the inner peripheral surface of the cylindrical piezoelectric element is provided is the tip portion, and the side on which the quadrant electrode portions (3a, 4a, 5a, 6a) are provided is the end portion, and the central axis direction is the Z axis. The right and left direction perpendicular to the Z axis is the X axis, and the direction perpendicular to the paper is the Y axis. When a cylindrical piezoelectric actuator is used, the end portion is usually fixed to the base block 8.

  Here, the belt-like electrode portion 7 on the outer peripheral surface is connected to the ground. A Z-axis drive power source 9 is connected to the folded electrode portion 2b connected to the strip electrode portion 2a on the inner peripheral surface. Further, two electrodes facing in the X-axis direction among the folded electrode portions (3b, 4b, 5b, 6b) on the outer peripheral surface connected to the four-divided electrode portions (3a, 4a, 5a, 6a) on the inner peripheral surface An X-axis drive power supply 10 is connected to the parts (3b, 4b), and a Y-axis drive power supply 11 is connected to the two electrode parts (5b, 6b) facing each other in the Y-axis direction. The folded electrodes (2b, 3b, 4b, 5b, 6b) are not necessarily provided, and may be directly connected to the internal electrodes (2a, 3a, 4a, 5a, 6a), but by providing the folded electrodes. Since the electrode for connecting the driving power source can be provided outside the cylinder, the connection is facilitated. When the strip electrode 7 on the outer peripheral surface is connected to the ground, it is grounded or connected to the ground side of the drive power source (9, 10, 11).

  When a voltage is applied to the Z-axis drive power supply 9 of the cylindrical piezoelectric actuator connected in this way, an attractive force or a repulsive force acts on the crystal inside the piezoelectric element according to the applied polarity, and distortion occurs in the thickness direction. This distortion also causes distortion in the Z-axis direction, and the piezoelectric element is displaced in the Z-axis direction. When a positive polarity voltage is applied by the Z-axis drive power source 9, distortion in the direction of increasing thickness occurs, and as a result, displacement occurs in the direction of contraction along the Z-axis. Conversely, when a negative polarity voltage is applied, displacement occurs in a direction extending along the Z axis.

  Also, when a voltage is applied to the X-axis drive power supply 10, the polarity of the crystals differs between the opposing electrodes (3a, 4a), so that one increases in thickness and the other decreases in thickness. As a result, one electrode contracts in a direction parallel to the central axis and the other electrode displaces in an extending direction, and the cylindrical piezoelectric actuator undergoes deflection in the X-axis direction around the fixed end at the end, and the tip is a circular arc. Do exercise. Here, since the displacement of the arc motion is very small, it can be considered that the displacement is approximately in the direction parallel to the X axis. By changing the polarity of the voltage of the X-axis drive power supply 10, it can be moved in both positive and negative directions with respect to the central axis. The Y axis can also be displaced in the Y axis direction by applying the voltage to the opposing electrodes (5a, 6a) using the Y axis drive power supply 11 by the same principle as the X axis. As a result, it is possible to move the tip of the piezoelectric element in an arbitrary direction within the XY plane by controlling the voltage applied to the X axis and the Y axis. In this embodiment, the voltage applied to the electrodes of each axis can be moved by 100 μm in the XY plane and 10 μm in the Z-axis direction by driving in the range of −200V to + 200V. Here, a cylindrical piezoelectric element in which the polarities of the electrodes facing the four divided electrode portions (3a, 4a, 5a, 6a) are the same polarity may be used. In this case, the cylindrical piezoelectric element is bent and deformed. In order to achieve this, it is necessary to apply voltages having opposite polarities to each axis using two power supplies, and a total of four drive power supplies are required for the two XY axes. As in this embodiment, the polarities of the opposing electrodes (3a, 4a) (5a, 6a) are polarized differently, so that the same polarity is achieved with two driving power sources, one for each axis and two for XY in total. The movement in the XY plane can be realized by applying the voltage.

  Next, a displacement detection method for the cylindrical piezoelectric actuator of this embodiment will be described. Piezoelectric actuators are usually used for the purpose of generating minute displacements on the order of sub-nanometers to several hundreds of micrometers, and the strain measurement accuracy required for measuring displacements due to the distortion of piezoelectric elements is usually 10-8 to 10-10. -3 or so. In order to measure such a small strain with high sensitivity, in this embodiment, the strain was measured by a strain gauge using a semiconductor as a resistor.

  FIGS. 3A and 3B show the structure of the strain gauge used in this embodiment and the fixing method to the piezoelectric element. 3A is a cross-sectional view taken along line AA of the strain gauge Rz1 attached to the piezoelectric element in FIG. 2B, and FIG. 3B is a front view of the strain gauge Rz1. All the other strain gauges of this embodiment have the same structure. The strain gauge Rz1 is an n-type semiconductor through a base material 16 made of a polyimide resin having a thickness of 15 μm as an insulator on an electrode 7 made of nickel formed on the outer peripheral surface of the element body 15 of the piezoelectric element 1. A configured linear resistor 17 is attached. Further, one end and the other end of the linear resistor 17 are connected to a resistor connecting electrode 18 patterned with nickel on the base 16, as shown in FIG. 3B. The resistor 17 and the resistor connecting electrode 18 are previously patterned on the base material 16 to form the strain gauge Rz1, and the base material 16 is bonded to the electrode portion 7 of the piezoelectric element with an epoxy adhesive.

  The strain gauges (Rz1, Rz3) for measuring the Z-axis strain are provided at two locations on the strip electrode portion 7 on the outer peripheral surface located on the surface side with respect to the strip electrode portion 2a provided on the inner peripheral surface. Bonding is performed so that the longitudinal direction of the body 17 is parallel to the central axis. These two resistors (Rz1, Rz3) are connected to the Z-axis displacement detector 9 installed outside via the resistor connecting electrode 18.

  Here, the detection principle of the displacement detection device will be described with reference to FIG. FIG. 4 is an electric circuit diagram including a resistor attached to the piezoelectric element and an external displacement detection device. In the displacement detection device, a bridge circuit is formed by using a total of four displacement detection resistors and fixed resistors connected inside the displacement detection device. Here, the numbers of the resistors in FIG. 4 correspond to the numbers of the displacement detection resistors attached to the electrodes, and are fixed resistors provided inside the displacement detection device other than the resistors attached to the piezoelectric elements. . Other embodiments of the present invention will also be described in correspondence with the numbers of the respective resistors attached to the piezoelectric elements, using the circuit diagram of FIG.

The Z electrode resistors (Rz1, Rz3) are incorporated in the R1 and R3 portions of the circuit diagram of FIG. The resistance value of the resistors (Rz1, Rz3) is 120Ω. R2 and R4 incorporate a fixed resistor having a resistance value of 120Ω. Here, a bridge voltage E is applied to the bridge circuit. In this embodiment, E is 2V. E may be direct current or alternating current, but in this embodiment, 30 kHz alternating current was used to improve noise resistance.
In the Z-axis displacement detection device 12 configured as described above, when the strain ε is generated in the piezoelectric element, the output voltage e is expressed by the following equation.
e = KEε / 2
Here, K is a gauge factor determined by the material of the resistor, and is about −100 in the case of the n-type semiconductor used also in this embodiment. It should be noted that the strain rate using a resistor of a metal material such as a copper nickel alloy that is most commonly used usually has a gauge factor of about 2. Therefore, by using a semiconductor gauge, the detection sensitivity is improved about 50 times.
From this equation, by measuring the output voltage E, the strain amount ε can be measured, and the displacement of the piezoelectric element can be obtained from the measured strain amount.

In addition, two gauges (Rx1, Rx2) (Ry1, each of the strip electrode portions 7 on the outer peripheral surface located on the surface side of the X electrodes (3a, 4a) and the Y electrodes (5a, 6a) of the four-divided electrode portions Ry2) is bonded, and fixed resistors are incorporated in R3 and R4 of FIG. The characteristics of each resistor are the same as those of the Z electrode. At this time, output voltages e of the X-axis displacement detector 13 and the Y-axis displacement detector 14 are expressed by the following equations.
e = KEε / 2
Therefore, the displacement of the X axis and the Y axis can also be measured by the output voltage of the displacement detector (13, 14).

Here, FIGS. 5A and 5B show a method of attaching the electrode patterns and resistors on the inner and outer peripheral surfaces of a conventional piezoelectric actuator with a displacement meter. In this prior art, the shape of the piezoelectric element and the shape of the electrode are merely the reverse of the inner electrode and the outer electrode in FIGS. 2 (a) and (b). Shows the same characteristics. In this prior art, the inner peripheral surface of the cylindrical piezoelectric element 20 is provided with a single strip electrode portion 21a along the circumference, and the folded electrode portion connected to the strip electrode portion 21a on the inner peripheral surface is provided at the distal end portion of the outer peripheral surface. 21b is provided, a strip electrode part 22 is provided along the circumference below the folded electrode part 21b, and a lower part 4 is formed in a direction parallel to the central axis by being divided into four along the circumference. Divided electrode portions (23, 24, 25, 26) are provided. The strip-like electrode portion 22 on the outer peripheral surface has a negative polarity, and the four-split electrode portions (23, 24, 25, 26) have opposite polarities to the electrodes (23, 24) (25, 26) facing the central axis. Thus, the polarization process is performed. The folded electrode portion 21b of the inner electrode on the outer peripheral surface is connected to the ground, and the Z-axis drive power supply 27 is connected to the belt-like electrode portion 22 on the outer peripheral surface with two corresponding electrodes (23, 24) (25, 26) is connected to an X-axis drive power supply 28 and a Y-axis drive power supply 29.
Further, the same strain gauge as that used in FIG. 2B is used as the displacement detection resistor of the piezoelectric element 20, and two pieces (Rz1, Rz3) are divided into four pieces on the belt-like electrode portion 22 on the outer peripheral surface. One piece (Rx1, Rx2, Ry1, Ry2) is attached on the electrode part (23, 24, 25, 26). Each resistor is connected to a Z-axis displacement detector, an X-axis displacement detector, and a Y-axis detector (not shown), and the bridge circuit shown in FIG. 4 is assembled.

  In the piezoelectric actuator with a displacement meter shown in FIGS. 2 and 5, the Z-axis is manufactured so that the polarities of polarization are different as shown in FIGS. 2B and 5B for the convenience of manufacture. When voltages of the same magnitude and the same polarity are applied by the shaft drive power supply (9, 27), different displacements in the moving direction are obtained with the same magnitude, and the X axis and Y axis are as shown in FIG. Since the electrodes are manufactured to have the same polarity as shown in FIG. 5B, when the same polarity and the same polarity voltage are applied by the driving power source, the same magnitude and displacement in the moving direction can be obtained.

  Here, only Rz1 of the two resistors of the Z-axis electrode of the piezoelectric actuator shown in FIGS. 2 (b) and 5 (b) is connected to the R1 portion of the bridge circuit shown in FIG. The rest was fixed resistance, and the output when a voltage was applied by the Z-axis drive power supply 27 was measured.

  A rectangular wave 34 of 0 to −100 V and 0.12 Hz is input to the piezoelectric actuator 1 of FIG. 2, and a rectangular wave 33 of 0 to +100 V and 0.12 Hz is input to the piezoelectric actuator 20 of FIG. FIG. 5 shows an optical displacement meter (interferometer) in which the displacement detection result by the strain gauge Rz1 and the displacement of the tip of the piezoelectric actuator (1, 20) are accurately configured. The results measured with a meter are shown in FIGS. 6 (a) and 6 (b). FIG. 6A shows the case where the electrode 7 provided with the resistor Rz1 in FIG. 2 is at the ground potential, and FIG. 6B shows the case of the prior art in which a drive voltage is applied to the electrode 22 provided with the resistor Rz1. It is. Here, both the detection signal of the strain gauge and the detection signal of the displacement meter are displaced in the direction in which the tip contracts when the voltage moves in the direction in which the voltage increases. When looking at the displacement 30 of the piezoelectric element by the displacement meter measured in FIG. 6B, it is observed that creeping in the direction in which the displacement occurs little by little after rising up to a certain distance by voltage application. . On the other hand, when the output 31 of the displacement detection device with the resistor Rz1 in FIG. 6B is seen, it is observed that the creep direction is moving in a direction completely opposite to the displacement direction 30 of the piezoelectric element. On the other hand, looking at the result of FIG. 6A, the output 32 of the displacement detection device at the resistor Rz1 coincides with the creep direction of the displacement 30 of the piezoelectric element measured by the displacement meter of FIG. 6B. The displacement of the piezoelectric actuator is accurately measured. In this experiment, the polarity of the electrode polarization was reversed due to the convenience of manufacturing the device. Therefore, the drive voltage was reversed in FIGS. 6A and 6B, but the measurement result was not affected. .

  As a result, a rectangular wave of 0 to +100 V and 0.12 Hz was applied to the piezoelectric actuator 1 of FIG. 2, and a rectangular wave of 0 to −100 V and 0.12 Hz was applied to the Z-axis drive power source to the piezoelectric actuator 20 of FIG. Measurement was also performed when the electrode was displaced in the opposite direction, but the same characteristics were exhibited, and the detection characteristics of the resistor Rz1 were irrelevant to the direction of distortion and the polarity of the applied voltage.

  In the conventional piezoelectric actuator 20 shown in FIG. 5, the resistor Rz1 is bonded to the band-like electrode portion 22 of the piezoelectric element to which the Z-axis drive power supply 27 is connected via an insulator. The insulator 17 is sandwiched between the resistor 17 or a connecting electrode portion (not shown) connected to the resistor, a potential difference is generated between the two, and it acts as a capacitor, and a capacitance component generated at that time This affects the signal of the Z-axis displacement detection device (not shown). By setting the electrode 7 provided with the resistor Rz1 as the ground potential as in the present invention of FIG. 2, there is almost no potential difference between them, and no capacitance component is generated, and accurate measurement is possible.

  In addition, for the four-divided electrode portions (3a, 4a, 5a, 6a) (23, 24, 25, 26) in FIGS. 2 (b) and 5 (b), two electrodes (3a, 4a) A rectangular wave is applied between (23, 24) and two electrodes (5a, 6a) (25, 26) facing each other on the Y axis, and each resistor unit (Rx1, Ry1, Rx2, Ry2) is bridged The output of the built-in displacement detector was measured.

When measuring the output of the resistor (Rx2, Ry2) that measures the distortion of the positive polarity electrodes (3a, 5a, 24, 26), a rectangular wave 43 of 0 to +100 V, 0.12 Hz is applied, When measuring the output of the resistors (Rx1, Ry1) that measure the distortion of the polar electrodes (4a, 6a, 23, 25), a rectangular wave 44 of 0 to −100 V, 0.12 Hz is applied and the same Measurements were made with displacement in the direction.
The measurement results with the conventional piezoelectric actuator 20 in FIG. 5 are shown in FIGS. 7A to 7D, and the measurement results with the piezoelectric actuator 1 of the present invention in FIG. 2 are shown in FIGS. In the output of the strain gauge, the direction in which the voltage increases is the direction in which the piezoelectric element contracts.

From the results shown in FIG. 7, the output signals (35, 36, 37, 38) of the strain gauges (Rx1, Ry1, Rx2, Ry2) have different creep sizes depending on the polarity of each electrode. The output signals (37, 38) of the strain gauges (Rx1, Ry1) have a larger creep amount than the output signals (35, 36) of the strain gauges (Rx2, Ry2) on the positive electrode, and are on the same polarity. The output characteristics (35, 36) and (37, 38) were the same characteristics. On the other hand, referring to the result of FIG. 8, when the electrode 7 provided with the resistors (Rx1, Ry1, Rx2, Ry2) is connected to the ground, each resistor (Rx1, Ry1, Rx2, Ry2) is provided. Regardless of the polarity of the electrodes (3a, 4a, 5a, 6a) on the inner peripheral surface side of the part, the output signals (39, 40, 41, 42) show the same creep characteristics, and the movement and distortion of the tip of the piezoelectric element 1 The outputs of the gauges (Rx1, Ry1, Rx2, Ry2) matched.
This is also because the electrostatic capacitance component affects the output signal of the strain gauge as in the case of the Z axis.

As for the XY electrode, when measuring the output of the resistor (Rx2, Ry2) for measuring the distortion of the positive polarity electrodes (3a, 5a, 24, 26), a rectangular shape of 0 to −100 V, 0.12 Hz. When measuring the output of a resistor (Rx1, Ry1) that applies a wave and measures the distortion of the negative polarity electrodes (4a, 6a, 23, 25), a rectangular wave of 0 to +100 V, 0.12 Hz is used. The strain gauge output was measured when applied and displaced in the direction opposite to that shown in FIGS. 7 and 8, but the creep characteristics were the same, and the detection characteristics of the resistor were independent of the direction of strain and the polarity of the applied voltage. Met.
In addition, when the insulation resistance is low due to the characteristics of the base material or humidity, the leakage current may flow and the measurement accuracy may deteriorate. However, if the surface on which the resistor is provided is the ground potential, the leakage current will also be It hardly occurs.
Accordingly, there is provided a piezoelectric actuator with a displacement meter that can detect displacement with high accuracy by a resistor without being affected by capacitance or leakage current by setting the surface on which the resistor is provided as a ground potential as in the present invention. The

  In addition, since a strain gauge is attached to the electrode surface to which a high voltage is applied in the conventional piezoelectric actuator, the resistance due to the contact of the resistor or the lead wire connected to the resistor to the electrode associated with the piezoelectric element, or the change over time. A phenomenon occurs in which the electrode for connecting the resistor on the insulator or the resistor on the insulator connected to the resistor through the inside of the insulator on which the body is provided is connected to the electrode of the piezoelectric element. Although the device may be damaged, since the electrode to which the resistor is attached is at the ground potential, these accidents can be prevented and the reliability and durability are improved.

  Moreover, since the electrode provided with the resistor is at the ground potential, the noise level of the displacement detection device itself is also reduced. Furthermore, when this piezoelectric actuator with a displacement meter is incorporated in the device, most of the electrodes on the outer peripheral surface of the piezoelectric actuator are connected to the ground, so noise is generated in the electrical wiring and the like arranged around the piezoelectric actuator. It is prevented from being mounted, and the anti-noise performance of the apparatus is improved.

FIGS. 9A and 9B show a cylindrical piezoelectric actuator 50 with a displacement meter according to a second embodiment of the present invention. FIG. 9A is a development view of the inner peripheral surface, and FIG. 9B is a development view of the outer peripheral surface.
In this embodiment, four resistors are arranged on each axis, and a bridge circuit is constituted by the four resistors, thereby increasing measurement sensitivity and compensating for the apparent distortion of the resistor due to temperature. In this embodiment, as shown in FIG. 9A, a folded electrode portion 51b connected to a strip-shaped electrode portion 51a on the outer peripheral surface described later is provided at the upper end of the inner peripheral surface, and a strip-shaped electrode portion 52 is provided below the folded electrode portion 51b. Further, a four-divided electrode portion (53a, 54a, 55a, 56a) formed in a direction parallel to the central axis by dividing the circumferential surface into four is provided thereunder. The strip electrode portion 52 is polarized to a plus electrode, and the four-divided electrode portions (53a, 54a, 55a, 56a) are such that the electrodes (53a, 54a) (55a, 56a) facing the central axis have opposite polarities. Was polarized.
As shown in FIG. 9 (b), the outer peripheral surface has folded electrode portions (53b, 54b, 55b, 56b) connected to the four-divided electrode portions (53a, 54a, 55a, 56a) on the inner peripheral surface at the lower end portion. A single strip electrode 51a is provided in the other portions.

The belt-like electrode portion 51a on the outer peripheral surface is connected to the ground, and the folded electrodes (53b, 54b, 55b, 56b) of the four-divided electrode portions (53a, 54a, 55a, 56a) on the outer peripheral surface are opposed to the central axis, respectively. An X-axis drive power supply 58 and a Y-axis drive power supply 59 are connected to each of the electrodes (53b, 54b) (55b, 56b) to be performed. Further, the Z-axis drive power source 57 is connected to the strip electrode portion 52 on the inner peripheral surface.
The resistor (Rz1, Rz2, Rz3, Rz4) for detecting the displacement in the vertical direction of the piezoelectric element 50 uses a strain gauge having the same specifications as in the first embodiment, and is a strip electrode portion connected to the ground on the outer peripheral surface. Strain gauges (Rz1, Rz3) are bonded at two arbitrary positions on the front side of the strip electrode portion 52 on the inner peripheral surface on 51a so that the longitudinal direction of the linear resistor 17 and the central axis of the cylinder are parallel to each other. The In addition, two strain gauges (Rz2, Rz4) are bonded to the front side of the folded electrode portion 51b on the inner peripheral surface on the strip electrode portion 51a on the outer peripheral surface.

  These strain gauges (Rz1, Rz2, Rz3, Rz4) are connected to the bridge circuit of FIG. Also in this embodiment, the numbers assigned to the strain gauges in FIG. 9B correspond to the resistor numbers in FIG.

When a voltage is applied to the belt-like electrode portion 52 on the inner peripheral surface by the Z-axis drive power source 57, the belt-like electrode portion 52 acts as an active electrode, causing displacement in a direction parallel to the central axis, and depending on the amount of distortion at that time Resistance values of the resistors Rz1 and Rz3 attached to the front side of the strip-shaped electrode portion 52 on the inner peripheral surface change. These two resistors (Rz1, Rz3) act as an active gauge for strain measurement.
On the other hand, the folded electrode portion 51b on the inner peripheral surface is connected to the strip-shaped electrode portion 51a on the outer peripheral surface, so that it acts as a dummy electrode and no distortion occurs. Two resistors (Rz2, Rz4) bonded to this portion are used as temperature compensating dummy gauges. In measurement using a strain gauge, the resistance value changes due to a change in ambient temperature or the heat generated by the resistor, and an apparent distortion occurs, resulting in a deterioration in measurement accuracy. In particular, the semiconductor gauge used in this embodiment has high sensitivity, but apparent strain due to temperature is large, and it is preferable to perform temperature compensation. By offsetting the apparent strain generated in the active gauges (Rz1, Rz3) with the apparent strain generated in the dummy gauges (Rz2, Rz4), the amount of strain is measured without being influenced by the apparent strain. The output of the Z-axis displacement detector configured as described above is expressed by the following equation.

e = KEε / 2
The output voltage itself is the same as in the case of the two strain gauges of Example 1, but there is no influence of apparent strain due to temperature, and the measurement accuracy is improved as compared to Example 1.
For detecting strain in the Z-axis direction, all four strain gauges are used as active gauges, of which two resistors are parallel to the central axis and the remaining two resistors are along the circumferential surface. By bonding, an output voltage of about e = 1.6 KEε / 2 can be obtained and temperature compensation is possible. However, when the semiconductor used for the resistor in this embodiment is attached to a curved surface, an accurate output is possible. Since it is not possible to obtain such a bonding method, only a metal resistor can be used. When the resistor is a semiconductor, it is effective to use a dummy gauge electrode as in this embodiment. It is.

Moreover, the resistor for detecting the displacement of the piezoelectric element in the horizontal direction is a linear resistor of two pieces each on the strip-like electrode part 51a on the front side of each of the four divided electrode parts (53a, 54a, 55a, 56a). Glue 17 so that it is parallel to the central axis. At this time, a total of four resistors (Rx1, Rx2, Rx3, Rx4) (Ry1, Ry2, Ry3, Ry4) bonded to the front side of the two opposing electrodes (53a, 54a) (55a, 56a) are shown in FIG. Connect to the bridge circuit. Also in this case, the resistor numbers in FIG. 9B correspond to the resistor numbers in FIG. The output of the displacement detector for each axis configured in this way is expressed by the following equation.
e = KEε
As can be seen from this equation, the output is doubled compared to the case where the bridge circuit is configured with two strain gauges of the first embodiment, and high sensitivity measurement is performed. In addition, the apparent distortion generated in each resistor is offset and temperature compensation can be performed.

  In this embodiment, two strain gauges (Rx1, Rx2, Rx3, Rx4) (Ry1, Ry2, Ry3, Ry4) bonded to the front side of the four-divided electrode portions (53a, 54a, 55a, 56a) are parallel. However, in the case of a cylindrical piezoelectric element, the same amount of strain can be obtained in the longitudinal direction regardless of the location as long as it is on the same electrode, so it is difficult to arrange the electrodes in a small parallel arrangement. In such a case, two strain gauges bonded to each electrode may be aligned and bonded in a straight line.

  FIGS. 10A and 10B show a cylindrical piezoelectric actuator 60 with a displacement meter according to a third embodiment of the present invention. FIG. 10A is a development view of the electrode on the inner peripheral surface, and FIG. 10B is a development view of the electrode on the outer peripheral surface. The driving direction of the piezoelectric element and the displacement detection method are the same as those in the first and second embodiments, so only the configuration will be described and the description of the operation will be omitted.

The piezoelectric actuator 60 with a displacement meter of the present embodiment is an actuator that is displaced in a direction parallel to the central axis. The inner peripheral surface is provided with strip-like electrode portions (61b, 62a) which are divided into two parts in the vertical direction.
The strip electrode portion 61b at the upper end is a folded electrode and is connected to the strip electrode portion 61a on the outer peripheral surface. The strip-shaped electrode portion 62a on the inner peripheral surface is polarized to a positive polarity.

  A strip electrode portion 61a is provided on the outer peripheral surface, and a folded electrode portion 62b connected to the strip electrode portion 62a on the inner peripheral surface is provided at the lower end.

  The strip electrode portion 61a on the outer peripheral surface is connected to the ground potential, and the strip electrode portion 62a on the inner peripheral surface is connected to the Z-axis drive power source 63 via the folded electrode portion 62b on the outer peripheral surface.

  The folded electrode 61b on the inner peripheral surface acts as a dummy electrode, and two strain gauges (Rz2, Rz4) are bonded to the strip electrode portion 61a on the outer peripheral surface. These two strain gauges (Rz2, Rz4) act as dummy gauges for temperature compensation. Further, the strip electrode portion 62a on the inner peripheral surface acts as an active electrode, and two strain gauges (Rz1, Rz3) are bonded to the strip electrode portion 61a on the outer peripheral surface of the surface, and these two strain gauges (Rz1) , Rz3) acts as an active gauge.

  These four strain gauges (Rz1, Rz2, Rz3, Rz4) are connected to the bridge circuit of FIG. 4 to constitute a displacement detection device. With this displacement detection device, an output having a magnitude of e = KEε / 2 is obtained, and temperature compensation is also performed.

  FIGS. 11A and 11B show a cylindrical piezoelectric actuator 70 with a displacement meter according to a fourth embodiment of the present invention. FIG. 11A is a development view of the electrode on the inner peripheral surface, and FIG. 11B is a development view of the electrode on the outer peripheral surface.

The piezoelectric actuator 70 with a displacement meter of the present embodiment is an actuator that is driven in a two-dimensional plane perpendicular to the central axis. The inner peripheral surface is divided into four along the circumference, and four divided electrodes (72a, 73a, 74a, 75a) are provided in a direction parallel to the central axis, and each electrode is an electrode (72a, 73a) facing the central axis. ) (74a, 75a) are polarized so as to have different polarities. On the outer peripheral surface, folded electrode portions (72b, 73b, 74b, 75b) connected to the four-divided electrode portions (72a, 73a, 74a, 75a) on the inner peripheral surface and a strip electrode portion 71 are provided.
Two electrodes (72a, 73a) (74a, 75a) facing the central axis of each of the four-divided electrode portions (72a, 73a, 74a, 75a) are folded electrode portions (72b, 73b, 74b, 75b) on the outer peripheral surface. ) To the X-axis drive power supply 76 and the Y-axis drive power supply 77, respectively. In addition, the strip electrode portion 71 on the outer peripheral surface is connected to the ground potential.
Two strips of the strain gauges (Rx2, Rx4) (Rx1, Rx3) (Ry2, Ry4) (Ry1, Ry3) are bonded. A total of four strain gauges (Rx1, Rx2, Rx3, Rx4) (Ry1, Ry2, Ry3, Ry4) bonded to two electrodes facing the central axis are connected to the bridge circuit of FIG. A displacement detection device is configured to detect the displacement in the biaxial direction.

  12 (a) and 12 (b) show a cylindrical piezoelectric actuator 80 with a displacement meter according to a fifth embodiment of the present invention. FIG. 12A is a development view of electrodes on the inner peripheral surface, and FIG. 12B is a development view of electrodes on the outer peripheral surface.

The piezoelectric actuator 80 with a displacement meter of the present embodiment is an actuator that is driven in a two-dimensional plane perpendicular to the central axis. The inner peripheral surface is divided into four along the circumference, and quadrant electrodes (82a, 83a, 84a, 85a) are provided in a direction parallel to the central axis. Each electrode (82a, 83a, 84a, 85a) is a positive electrode and is polarized so as to have the same polarity. On the outer peripheral surface, there are provided folded electrode portions (82b, 83b, 84b, 85b) connected to the four-divided electrode portions (82a, 83a, 84a, 85a) on the inner peripheral surface, and a strip electrode portion 81.
The quadrant electrode portions (82a, 83a, 84a, 85a) are connected to the X-axis drive power source (86, 87) and the Y-axis drive power source (88, 89) via the folded electrode portions (82b, 83b, 84b, 85b) on the outer peripheral surface. ) Are alternately connected. Further, the belt-like electrode portion 81 on the outer peripheral surface is connected to the ground potential.
In this embodiment, two power supplies (86, 87) (88, 89) are applied to each axis to apply voltages of opposite phases to each other to generate a deflection with respect to the central axis, so that the tip is in a two-dimensional plane. Drive with.
Two strips of gauges (Rx2, Rx4) (Rx1, Rx3) (Ry2, Ry4) (Ry1, Ry3) are bonded. A total of four strain gauges (Rx1, Rx2, Rx3, Rx4) (Ry1, Ry2, Ry3, Ry4) bonded to two electrodes facing the central axis are connected to the bridge circuit of FIG. A displacement detection device is configured to detect the displacement in the biaxial direction.

  13 (a) and 13 (b) show a cylindrical piezoelectric actuator 90 with a displacement meter according to a sixth embodiment of the present invention. FIG. 13A is a development view of the electrode on the inner peripheral surface, and FIG. 13B is a development view of the electrode on the outer peripheral surface.

The piezoelectric actuator 90 with a displacement meter of the present embodiment is an actuator for generating displacement in a direction parallel to the central axis. The inner peripheral surface is provided with a belt-like folded electrode portion 91b connected to the belt-like electrode portion 91a on the outer peripheral surface at the upper end portion, and is formed in a direction parallel to the central axis by being divided into four along the circumference. Quadrant electrode parts (92a, 93a, 94a, 95a) are provided. All the electrodes of the quadrant electrode portions (92a, 93a, 94a, 95a) are positive electrodes and are polarized so as to have the same polarity. On the outer peripheral surface, there are provided folded electrode portions (92b, 93b, 94b, 95b) connected to the four-divided electrode portions (92a, 93a, 94a, 95a) on the inner peripheral surface, and a strip electrode portion 91a.
One quadrant electrode portion (92a, 93a, 94a, 95a) is provided for each Z-axis drive power source (96, 97, 98, 99) via a folded electrode portion (92b, 93b, 94b, 95b) on the outer peripheral surface. ) Is connected. Further, the strip electrode portion 91a on the outer peripheral surface is connected to the ground potential.

  In the present embodiment, voltages having the same polarity and the same magnitude are applied from the respective Z power source driving power sources (92a, 93a, 94a, 95a) connected to the four-divided electrode portions (92a, 93a, 94a, 95a). The piezoelectric element of each electrode portion (92a, 93a, 94a, 95a) is distorted in the same direction, and the piezoelectric actuator 90 can be driven in a direction parallel to the central axis. Here, depending on the processing accuracy of the piezoelectric element, even when the same voltage is applied, it may not operate completely parallel to the central axis. In such a case, it is possible to correct the deviation by adjusting the voltage applied to the four-divided electrode portions (92a, 93a, 94a, 95a), and to ensure straightness.

In this embodiment, two strain gauges (Rz1, Rz3) are provided on the belt-like electrode portion 91a on the outer peripheral surface located on the front side of each electrode of the four-divided electrode portions (92a, 93a, 94a, 95a) that act as active electrodes. Adhering and acting as an active gauge, two strain gauges (Rz2 and Rz4) are adhered to the belt-like electrode portion 91a on the outer peripheral surface on the front side of the folded electrode portion 91b on the inner peripheral surface acting as a dummy electrode, for temperature compensation. Use as a dummy gauge. These four strain gauges (Rz1, Rz2, Rz3, Rz4) are connected to the bridge circuit of FIG. 4 to constitute a displacement detection device, and displacement detection in a direction parallel to the central axis is performed.
Here, the manufacturing method of a division | segmentation electrode is demonstrated taking FIG. 13, FIG. 14 as an example. In this embodiment, electrode division was performed using two methods.
In the first method, electrodes were prepared on all of the inner peripheral surface, the outer peripheral surface, and both end surfaces, and then divided by removing the electrodes by processing.
For the production of the electrode, the piezoelectric body is molded into a cylinder and then degreased and washed, and palladium acting as a catalyst is adsorbed on the entire surface of the element and dried. Next, it is immersed in a plating solution to perform electroless nickel plating, and nickel having a thickness of about 3 μm is provided on the entire surface.
A segmented electrode was fabricated by cutting a part of the nickel layer on the inner and outer peripheral surfaces and the surface of the piezoelectric body with a diamond-coated tool. Since the outer electrode can be divided relatively easily, the working time can be shortened if the divided electrode is formed only on the outer peripheral surface with a masking tape or the like in the plating step.
In the second method, division was performed by masking a portion where no electrode was provided.
In this method, a piezoelectric body is molded into a cylinder, degreased and washed, and then a resist solution is applied along a dividing line and dried. Next, palladium was adsorbed and dried, the resist was removed, and immersed in a plating solution to selectively perform electroless nickel plating only on the portion where palladium was adsorbed, thereby producing divided electrodes.
In addition, it is also possible to change the order of the steps and to divide by a method such as palladium adsorption → resist application → electroless nickel plating → resist removal or resist application → palladium adsorption → electroless nickel plating → resist removal.
Note that the type of masking is not limited to resist, and a masking tape or other masking technique can also be used.
Moreover, the kind of electrode is not limited to nickel, Arbitrary conductors, such as silver, gold | metal | money, and carbon, can be used.
These manufacturing methods can be applied to other embodiments of the present invention.
In addition, the piezoelectric element used in Example 3 and Example 6 may be configured by separately forming a piezoelectric element having an active electrode and a piezoelectric element having a dummy electrode, and bonding them using a connecting member such as ceramics. In this case, the process of dividing the inner peripheral surface can be omitted, and the manufacture becomes easier than in the case of integral molding.
In addition, in the piezoelectric elements shown in Examples 1 to 6, the electrode connected to the ground potential on the outer peripheral surface is formed of a uniform strip electrode, but the electrode provided with the resistor on the outer peripheral surface is also divided into copper electrodes. A line or the like may be connected so as to have the same potential, and may be connected to the ground potential.

  14 (a), 14 (b) and 15 show a cylindrical piezoelectric actuator 100 with a displacement meter according to a seventh embodiment of the present invention. FIG. 14A is a development view of the electrode on the inner peripheral surface, and FIG. 14B is a development view of the electrode on the outer peripheral surface. FIG. 15 is a cross-sectional view taken along the line BB of the strain gauge mounting portion of FIG.

  As shown in FIG. 14A, the inner peripheral surface is provided with a single strip electrode portion 101a. Further, as shown in FIG. 14B, on the outer peripheral surface, the folded electrode portion 101b connected to the strip-shaped electrode portion 101a on the inner peripheral surface, the strip-shaped electrode portion 103, and the four-divided electrode portions (104, 105, 106, 107). Consists of The belt-like electrode portion 103 on the outer peripheral surface is polarized to a positive polarity, and the four-divided electrode portions (104, 105, 106, 107) have different electrodes (104, 105) (106, 107) facing the central axis. Polarization is performed so as to be polar.

  The strip electrode portion 101a on the inner peripheral surface is connected to the ground potential via the folded electrode portion 101b on the outer peripheral surface, and the strip electrode portion 103 on the outer peripheral surface is connected to the Z-axis drive power supply 110 and is divided into four divided electrode portions (104, 105). , 106, 107) are respectively connected to the X-axis drive power supply 111 and the Y-axis drive power supply 112, respectively.

  In this embodiment, as shown in FIG. 15, two electrodes are provided in the strip-like electrode portion 103 on the outer peripheral surface and one electrode is provided in each electrode portion of the four-divided electrode portion (104, 105, 106, 107). The non-region 108 was formed, and strain gauges (Rz1, Rz3, Rx1, Rx2, Ry1, Ry2) were directly bonded to the piezoelectric element 112. The specifications of the strain gauge and the bonding method are the same as in the first embodiment. For each of these axes, two strain gauges (Rz1, Rz3) (Rx1, Rx2) (Ry1, Ry2) and two fixed resistors are incorporated in the bridge circuit of FIG. 4 to constitute a displacement detection device.

By directly bonding the strain gauge to the piezoelectric element in this manner, the piezoelectric element electrodes (103, 104, 105, 106, 107) do not exist on the bonding surface side of the strain gauge base 16, so that electrostatic capacity is not generated. Therefore, the capacitance does not adversely affect the detection signal of the strain gauge.
Compared with the case where the divided electrodes are provided on the inner peripheral surface, the present embodiment makes it easier to manufacture the electrodes of the piezoelectric element because the divided electrodes are formed on the outer peripheral surface.
When the resistor is directly provided on the piezoelectric element as in this embodiment, it is not always necessary to provide the resistor via an insulating base, and the resistor may be directly fixed on the piezoelectric element.

  16 (a), 16 (b) and 17 show a cylindrical piezoelectric actuator 120 with a displacement meter according to an eighth embodiment of the present invention. FIG. 16A is a development view of the electrode on the inner peripheral surface, and FIG. 16B is a development view of the electrode on the outer peripheral surface. FIG. 17 is a cross-sectional view taken along the line CC of the strain gauge mounting portion of FIG.

  As shown in FIG. 16A, the inner peripheral surface is provided with a single strip electrode 121a. Further, as shown in FIG. 16B, on the outer peripheral surface, the folded electrode portion 121b connected to the strip-shaped electrode portion 121a on the inner peripheral surface, the strip-shaped electrode portion 122, and the four-divided electrode portions (123, 124, 125, 126). ). The belt-like electrode portion 122 on the outer peripheral surface is polarized with a positive polarity, and the four-divided electrode portions (123, 124, 125, 126) are different from each other in the electrodes (123, 124) (125, 126) facing the central axis. Polarization is performed so as to be polar.

  The belt-like electrode portion 121a on the inner circumferential surface is connected to the ground potential via the folded electrode portion 121b on the outer circumferential surface, and the belt-like electrode portion 122 on the outer circumferential surface is connected to the Z-axis drive power source 129 and is divided into four divided electrode portions (123, 124). , 125, 126), the two electrodes (123, 124) (125, 126) opposed to the central axis are connected to the X-axis drive power supply 130 and the Y-axis drive power supply 131, respectively.

  In this embodiment, as shown in FIG. 17, each electrode is provided at two locations in the belt-like electrode portion 122 on the outer peripheral surface and at one location on each electrode portion of the four-divided electrode portions (123, 124, 125, 126). An electrode 128 for attaching a strain gauge independent from the above was prepared, and strain gauges (Rz1, Rz3, Rx1, Rx2, Ry1, Ry2) were bonded onto the electrode 128 for attaching a strain gauge. The specifications of the strain gauge and the bonding method are the same as in the first embodiment. For each of these axes, two strain gauges (Rz1, Rz3) (Rx1, Rx2) (Ry1, Ry2) and two fixed resistors are incorporated in the bridge circuit of FIG. 4 to constitute a displacement detection device.

Here, although the strain gauge attaching electrode portion 128 may be connected to the ground, in this embodiment, it is set to the same potential as the voltage applied to the resistor 17. As described above, the strain gauge mounting electrode 128 is provided independently of the electrodes (122, 123, 124, 125, 126) connected to the driving power sources (129, 130, 131) of the piezoelectric element, and the strain gauge is provided thereon. By adhering (Rz1, Rz3, Rx1, Rx2, Ry1, Ry2), no electrostatic capacitance is generated in the strain gauge attaching portion, and the electrostatic capacitance does not adversely affect the strain gauge detection signal.
In this embodiment, since the resistor 17 on the strain gauge base material 16 and the resistor connecting electrode (not shown) and the strain gauge attaching electrode portion 128 are at the same potential, the strain gauge attaching electrode portion 128. It is possible to further eliminate the influence of the electrostatic capacity than when connecting to the ground.
Thus, the method of setting the potential of the strain gauge mounting electrode portion to the same potential as the voltage applied to the resistor can be applied instead of connecting the electrode to the ground in another embodiment of the present invention.

FIG. 18 shows a bimorph type piezoelectric actuator 140 with a displacement meter according to a ninth embodiment of the present invention.
The bimorph piezoelectric actuator 140 includes two plate-like piezoelectric elements (both of which are polarized so that distortions in the opposite directions in the longitudinal direction are generated on both surfaces of a plate-like elastic member 141 made of an elastic material such as phosphor bronze). 142, 143) is fixed, and the piezoelectric element (142, 143) is distorted to generate distortion, thereby causing the support point 149 to bend. The upper and lower piezoelectric elements (142, 143) are provided with electrodes (144, 145, 146, 147) on the surface side and the side bonded to the elastic body.

  In this embodiment, two strain gauges (R1, R2) (R3, R4) are provided on the surface side electrodes (144, 145) of the piezoelectric elements (142, 143) bonded to the upper and lower surfaces of the elastic body 141, respectively. Bonding was performed so that the strain in the major axis direction could be measured, and a bridge circuit was assembled with a total of four strain gauges (R1, R2, R3, R4) to detect displacement in the bending direction.

The strain gauge (R1, R2, R3, R4) used in this example is a metal resistor in which a resistor is patterned with a copper nickel alloy on an insulating base material having a thickness of 15 μm mixed with a phenol resin and an epoxy resin. The strain gauge was used. The resistance value is 120Ω and the gauge factor is 2.
Here, in this embodiment, the electrodes (144, 145) to which the strain gauges (R1, R2, R3, R4) are attached are set to the ground potential, and are driven to the electrodes (146, 147) on the joint surface side with the elastic body. A power source 148 was connected.

By connecting in this way, no capacitance is generated in the strain gauge (R1, R2, R3, R4) portion, the displacement detection signal can be detected without the influence of the capacitance component, and the detection accuracy is improved. To do.
A unimorph type piezoelectric actuator can be formed by fixing a piezoelectric element only to one surface of the elastic body.

  FIG. 19 shows a laminated piezoelectric actuator 150 with a displacement meter according to a tenth embodiment of the present invention. The laminated piezoelectric actuator 150 is formed by alternately laminating film-like piezoelectric elements 151 and electrodes (151 and 152) that are polarized in the thickness direction. Adjacent film-like piezoelectric elements 151 are arranged such that the polarities of polarization are opposite to each other. The upper and lower electrodes of the film-like piezoelectric element 151 are alternately connected to electrodes (152, 153) provided on the side surfaces of the multilayer piezoelectric element. One electrode 153 on this side is connected to the ground, and the other electrode 152 is connected to the drive power source 156.

To the electrode 153 connected to the ground electrode, the same strain gauge R1 composed of the base material 155 and the resistor 154 as used in the ninth embodiment is bonded so that the strain in the longitudinal direction can be detected. By connecting the strain gauge R1 to the displacement detection device, the displacement of the multilayer piezoelectric actuator 150 can be detected.
Also in this embodiment, since the strain gauge R1 is connected to the ground electrode side, no capacitance is generated at the mounting portion of the strain gauge R1, and the displacement detection signal is not affected by the capacitance component. The detection accuracy can be improved.

FIG. 20 shows a configuration of a scanning probe microscope 160 using the piezoelectric actuator 50 of the second embodiment as an example of a positioning apparatus using a piezoelectric actuator with a displacement meter.
In this embodiment, the end of the piezoelectric actuator 50 shown in FIG. 9 is fixed to the base 173, and the sample holder 172 is fixed to the tip, which is used as a three-axis fine movement mechanism.

On the side facing the sample 171 placed on the sample holder 172, a cantilever 169 having a probe 170 at the tip is fixed to the cantilever holder 168.
The displacement of the cantilever 169 is measured by an optical lever type displacement detection mechanism 164 including a semiconductor laser 165, a condensing lens 166, and a photodetector 167.

  In the present embodiment, the probe surface 170 and the sample 171 are brought close to the region where the atomic force acts, and the sample surface is used by using the quadrant electrode portions (53a, 54a, 55a, 56a) of the piezoelectric actuator 50 with a displacement meter. While performing a raster scan in a direction parallel to the inside, feedback is made in a direction perpendicular to the sample plane using the strip electrode unit 52 by a signal from the displacement detection mechanism 164 so that the distance between the probe 170 and the sample 171 is constant. Take control.

At this time, the movement in the XY directions is performed by the X-axis displacement detection device 162 and the Y-axis displacement detection device 163 by the strain gauges (Rx1, Rx2, Rx3, Rx4) (Ry1, Ry2, Ry3, Ry4) provided on each axis. From the measured displacement, feedback control is performed so as to operate linearly with respect to the drive voltage applied to the piezoelectric actuator 50 by the X-axis drive power supply 58 and the Y-axis drive power supply 59.
The Z-axis displacement detector 161 uses a strain gauge (Rz1, Rz2, Rz3, Rz4) attached to the Z-axis as a signal applied to XY by the scanning probe microscope 160 configured in this way as information on a two-dimensional plane. A three-dimensional uneven shape can be measured by imaging the detected displacement signal as height information.

  As for the Z axis, if the signal of the Z axis displacement detection device 161 is imaged, accurate height information can be measured without linearly moving the Z axis with respect to the applied voltage. When feedback control is performed so that the displacement amount is linearly operated with respect to the Z-axis drive voltage, the voltage applied to the Z-axis by the Z-axis drive power supply 57 can be displayed as height information.

FIG. 21 shows an example in which a scanning probe microscope 180 is configured by combining the piezoelectric actuators (60, 70) of Example 3 and Example 4 as an example of a positioning device using a piezoelectric actuator with a displacement meter.
In the present embodiment, the end of the horizontal driving piezoelectric actuator 70 shown in FIG. 11 is fixed to a base (not shown), and the vertical driving shown in FIG. A piezoelectric actuator 60 is connected, a cantilever holder 185 is provided at the tip of the piezoelectric actuator 60 for vertical driving, and a cantilever 190 having a probe 191 is fixed at the tip, which is used as a three-axis fine movement mechanism.

A sample holder 193 is provided on the side facing the probe 191 and a sample 192 is placed thereon.
The displacement of the cantilever 190 is measured by an optical lever type displacement detection mechanism 186 composed of a semiconductor laser 187, a condenser lens 188 and a photodetector 189.
The operation of this embodiment is the same as that of the eleventh embodiment except that the eleventh embodiment scans the sample 171. In this embodiment, the operation other than the scanning of the cantilever 190 is the same as that of the eleventh embodiment.

When a divided electrode is manufactured on the inner peripheral surface of a cylindrical piezoelectric element, a technique is required for dividing the electrode as compared with the case of manufacturing on an outer peripheral surface. However, as in this embodiment, the horizontal fine movement mechanism 70 and the vertical direction are required. By dividing the fine movement mechanism 60, the divided area of the internal electrode of the single cylindrical piezoelectric actuator (60, 70) is reduced, and the fabrication can be easily performed.
Further, by connecting the electrodes (71, 61a) on the outer peripheral surface of the cylindrical piezoelectric actuator to the ground as in the case of the eleventh and twelfth examples, not only the strain gauge detection signal but also around the cylindrical piezoelectric actuator. Mixing of noise into the wiring materials and electrical components to be arranged is reduced, and as a result, the noise level of the measurement data is reduced. This is particularly effective when measuring the electrical characteristics of the sample surface with a scanning probe microscope.
Further, in addition to the strain gauge wiring material, other wiring materials and electrical components arranged around the electrode of the piezoelectric actuator can be prevented from being short-circuited.

The present invention is not limited to the embodiments described above.
Any shape of the piezoelectric element can be used. As long as the electrode on the piezoelectric element is conductive, other materials such as copper, silver and gold can be used in addition to nickel. In addition, when an insulating coat is applied on the electrode at the manufacturing stage of the piezoelectric element, and a resistor fixed to the base of the insulator is stuck on the electrode, the substantial structure is the same as that of the present invention. Included in the invention.
The material of the resistor is also arbitrary, and besides the n-type semiconductor and the copper-nickel alloy introduced in the embodiments, a nichrome-based alloy, a p-type semiconductor, a semiconductor combining n-type and p-type, and the like can be used. Also, the shape of the resistor is not limited to a linear shape, and an arbitrary shape can be used.
In addition, as the base material of the insulator on which the resistor is provided, any insulating material such as paper, phenol resin, and epoxy resin can be used in addition to polyimide resin and phenol-epoxy mixed resin. Also, the fixing method of the base material is not necessarily limited to adhesion, and a resistor may be provided directly on the base material by using a vapor deposition such as SiO ₂ or an insulating adhesive itself. In addition to the scanning probe microscope, the positioning device in which the piezoelectric actuator with a displacement meter of the present invention is used is, for example, an optical microscope, a laser microscope, a semiconductor manufacturing apparatus, a semiconductor inspection apparatus, a machine tool, OA equipment, and AV equipment. It can be applied to various devices such as optical instruments.

It is a general-view figure of the cylindrical type piezoelectric actuator with a displacement meter which concerns on 1st Example of this invention. (A) It is an expanded view of the internal peripheral surface of the cylindrical piezoelectric element used by the 1st Example of this invention. (B) It is an expanded view of the outer peripheral surface of the cylindrical piezoelectric element used by the 1st Example of this invention. (A) It is the sectional view on the AA line of FIG.2 (b). (B) It is a front view of Fig.3 (a). It is a circuit diagram of a displacement detection apparatus. (A) It is an expanded view of the internal peripheral surface of the conventional cylindrical piezoelectric element. (B) It is an expanded view of the outer peripheral surface of the conventional cylindrical piezoelectric element. (A) It is the detection data of a strain gauge when a rectangular wave is applied to the Z-axis of the cylindrical piezoelectric actuator with a displacement meter of the present invention in FIG. (B) Displacement data measured by an interferometer when a rectangular wave is applied to the Z axis of the conventional cylindrical piezoelectric actuator with a displacement meter in FIG. 5 and strain gauge detection data. (A)-(d) It is the detection data of the strain gauge provided in each electrode when a rectangular wave is applied to the X-axis and Y-axis electrodes of the conventional cylindrical piezoelectric actuator with a displacement meter of FIG. (A)-(d) It is the strain gauge detection data provided in each electrode when a rectangular wave is applied to the X-axis and Y-axis electrodes of the cylindrical piezoelectric actuator with a displacement meter of FIG. (A) It is an expanded view of the internal peripheral surface of the cylindrical piezoelectric element of 2nd Example of this invention. (B) It is an expanded view of the outer peripheral surface of the cylindrical piezoelectric element of 2nd Example of this invention. (A) It is an expanded view of the internal peripheral surface of the cylindrical piezoelectric element of the 3rd Example of this invention. (B) It is an expanded view of the outer peripheral surface of the cylindrical piezoelectric element of the 3rd Example of this invention. (A) It is an expanded view of the internal peripheral surface of the cylindrical piezoelectric element of 4th Example of this invention. (B) It is an expanded view of the outer peripheral surface of the cylindrical piezoelectric element of 4th Example of this invention. (A) It is an expanded view of the internal peripheral surface of the cylindrical piezoelectric element of 5th Example of this invention. (B) It is an expanded view of the outer peripheral surface of the cylindrical piezoelectric element of 5th Example of this invention. (A) It is an expanded view of the internal peripheral surface of the cylindrical piezoelectric element of 6th Example of this invention. (B) It is an expanded view of the outer peripheral surface of the cylindrical piezoelectric element of 6th Example of this invention. (A) It is an expanded view of the internal peripheral surface of the cylindrical piezoelectric element of 7th Example of this invention. (B) It is an expanded view of the outer peripheral surface of the cylindrical piezoelectric element of 7th Example of this invention. It is BB sectional drawing of FIG.14 (b). (A) It is an expanded view of the internal peripheral surface of the cylindrical piezoelectric element of 8th Example of this invention. (B) It is an expanded view of the outer peripheral surface of the cylindrical piezoelectric element of 8th Example of this invention. It is CC sectional view taken on the line of FIG.16 (b). It is a general-view figure of the bimorph type piezoelectric actuator with a displacement meter which concerns on 9th Example of this invention. It is a general-view figure of the multilayer type piezoelectric actuator with a displacement meter which concerns on 10th Example of this invention. It is a general-view figure of the scanning probe microscope using the cylindrical piezoelectric actuator with a displacement meter based on the 11th Example of this invention. It is a general-view figure of the scanning probe microscope using the cylindrical piezoelectric actuator with a displacement meter based on 12th Example of this invention. It is a general-view figure of the scanning probe microscope using the conventional cylindrical type piezoelectric actuator with a displacement meter. It is a general-view figure of the cylindrical type piezoelectric actuator with a displacement meter used with the scanning probe microscope of FIG. FIG. 24 is a circuit diagram used for horizontal displacement detection in the cylindrical piezoelectric actuator with a displacement meter of FIG. 23. FIG. 24 is a circuit diagram used for vertical displacement detection in the cylindrical piezoelectric actuator with a displacement meter of FIG. 23.

Explanation of symbols

1, 20, 50, 60, 70, 80, 90, 100, 120 Cylindrical piezoelectric actuator with displacement gauge Rz1, Rz2, Rz3, Rz4, Rx1, Rx2, Rx3, Rx4, Ry1, Ry2, Ry3, Ry4, R1 , R2, R3, R4 Strain gauge (resistor)
12, 161, 183 Z-axis displacement detectors 13, 162, 181 X-axis displacement detectors 14, 163, 182 Y-axis displacement detector 16 Base material (insulator)
17 Resistor 18 Resistor connection electrode 9, 27, 57, 63, 96, 97, 98, 99, 109, 129 Z-axis drive power supply 10, 28, 58, 76, 86, 87, 110, 130 X-axis drive Power supply 11, 29, 59, 77, 88, 89, 111, 131 Y-axis drive power supply 148, 156 Drive power supply 140 Bimorph type piezoelectric actuator with displacement meter 150 Laminated piezoelectric actuator with displacement meter

Claims (15)

  A piezoelectric element formed in an arbitrary shape, whose inner crystal is polarized in an arbitrary direction, and electrodes are provided on at least two opposing surfaces in the thickness direction, and a voltage is applied between the electrodes to apply the piezoelectric A drive power source for generating distortion in the element, a resistor provided on the electrode via an insulator, and connected to the resistor, an arbitrary voltage is applied to the resistor to change a resistance value. A piezoelectric actuator with a displacement meter, comprising a displacement detection device that detects a strain amount of the piezoelectric element by detecting the electrode, and connecting an electrode on the piezoelectric element provided with a resistor to a ground potential.   A piezoelectric element formed in an arbitrary shape, whose inner crystal is polarized in an arbitrary direction, and electrodes are provided on at least two opposing surfaces in the thickness direction, and a voltage is applied between the electrodes to apply the piezoelectric A drive power source for generating distortion in the element, a resistor provided on the electrode via an insulator, and connected to the resistor, an arbitrary voltage is applied to the resistor to change a resistance value. A piezoelectric actuator with a displacement meter, comprising a displacement detection device that detects the amount of strain of the piezoelectric element by detecting it, wherein the potential of the electrode on the piezoelectric element provided with the resistor is equal to the potential applied to the resistor.   The piezoelectric element according to claim 1 or 2, wherein the piezoelectric element is formed in a cylindrical shape, electrodes are provided on both an inner peripheral surface and an outer peripheral surface of the cylindrical piezoelectric element, and a resistor is provided on the electrode on the outer peripheral surface via an insulator. The cylindrical piezoelectric actuator with a displacement meter according to any one of the above.   The cylindrical piezoelectric actuator with a displacement meter according to claim 3, wherein the electrode on the inner peripheral surface is divided into a plurality of parts.   A single band-shaped electrode in which the outer peripheral surface electrode is provided along the outer periphery, or a folded electrode in which the outer peripheral surface electrode is connected to the inner peripheral surface and a single band-shaped electrode are formed. 5. A piezoelectric actuator with a displacement meter according to claim 3, wherein a resistor is provided.   At least two or more electrodes are provided on the inner peripheral surface of the cylindrical piezoelectric element, and an electrode is also provided on the outer peripheral surface facing the inner peripheral electrode via a piezoelectric body. One electrode is a dummy electrode that does not cause distortion, the other electrode is an active electrode that generates distortion in the piezoelectric element by applying a voltage, and one or two resistors are provided on the outer electrode of the active electrode, One or two resistors are provided on the outer electrode of the dummy electrode, and at least the electrode on which the resistor is provided is configured to have the same potential and connected to the ground potential, and on the outer peripheral surface side of the active electrode When the strain is detected by the provided resistor, each resistor between the active electrode and the dummy electrode is subjected to temperature compensation by the resistor provided on the outer peripheral surface side of the dummy electrode. The piezoelectric actuator with displacement meter according to any one of claims 3 to 5, characterized in that to constitute a bridge circuit by connecting the body.   7. The piezoelectric actuator with a displacement meter according to claim 6, wherein the piezoelectric element having the dummy electrode and the piezoelectric element having the active electrode are configured separately using the same piezoelectric material.   The electrode on the outer peripheral surface or / and the inner peripheral surface is formed by removing a part of the electrode by machining after providing the electrode on the surface of the piezoelectric body. A piezoelectric actuator with a displacement meter as described in 1.   The electrode on the outer peripheral surface or / and the inner peripheral surface is formed by removing the mask after masking the surface of the piezoelectric body and providing an electrode in a portion other than the masking. A method for manufacturing a piezoelectric actuator with a displacement meter according to any one of claims 1 to 7.   A plate-like piezoelectric element is fixed to the upper and / or lower surface of an arbitrary plate-like elastic body, electrodes are provided on the surface of the piezoelectric element and the interface with the elastic body, respectively, and the surface-side electrode of the piezoelectric element is insulated. 3. The piezoelectric actuator with a displacement meter according to claim 1, wherein the piezoelectric actuator is a bimorph type or a unimorph type provided with a resistor through a body.   A plurality of film-shaped piezoelectric elements and electrodes are alternately stacked to form a stacked piezoelectric element, and two electrodes alternately connected to the electrodes sandwiched between the film-shaped piezoelectric elements are connected to the stacked piezoelectric elements. The piezoelectric actuator with a displacement meter according to claim 1 or 2, wherein the piezoelectric actuator is a laminated type formed on a side surface and provided with a resistor on one electrode of the side surface electrode through an insulator.   A piezoelectric element formed in an arbitrary shape, whose inner crystal is polarized in an arbitrary direction, and electrodes are provided on at least two opposing surfaces in the thickness direction, and a voltage is applied between the electrodes to apply the piezoelectric element Displacement detection that detects the amount of distortion of the piezoelectric body by detecting a change in resistance value, connected to the resistor, and a driving power source for generating strain in the element, a resistor provided on the piezoelectric element A piezoelectric actuator with a displacement meter, characterized in that the portion provided with the resistor is provided with no electrode on the piezoelectric element.   13. The piezoelectric actuator with a displacement meter according to claim 1, wherein the resistor is a semiconductor.   The piezoelectric element used for the piezoelectric actuator with a displacement meter in any one of Claims 1 thru | or 13.   A positioning device using the piezoelectric actuator with a displacement meter according to claim 1.

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