JP2000152670A - Piezoelectric-crystal element and actuator using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric-crystal element that enable complex movements including an elliptical motion with a simple structure, and an actuator using it. SOLUTION: A piezoelectric-crystal element 10 is constituted by stacking unit piezoelectric elements 11a-11f. The surface of each of the unit piezoelectric elements 11a-11f is divided into four to form four electrodes 12p, 12q, 12r, 12s and to constitute a stacked drive electrode unit. When a DC drive voltage is applied to all of the driving electrode units 12p-12s, displacement occurs as a whole. If a drive voltage is applied to a part of the drive electrode units 12p-12s, displacement occurs only on the piezoelectric elements of the electrode part to which a voltage has been applied, the piezoelectric-crystal element 10 is deformed partially, and elliptical motion or circular motion occurs at the tip. A driven member, fixed in friction contact with the tip of the piezoelectric-crystal element 10 via an actuating member, can be caused to perform rotational movement around three axes (X, Y, Z axes).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric transducer, and more particularly to an electrode structure of a laminated piezoelectric transducer and an actuator using the piezoelectric transducer.

[0002]

2. Description of the Related Art A laminated piezoelectric transducer has a high conversion efficiency for converting supplied electric energy into a driving force, is small in size and light in weight, generates a large driving force, and can easily control the driving force. Therefore, it is widely used for driving and positioning various members constituting a camera, a measuring instrument, and other precision machines.

[0003] A piezoelectric transducer used in such an actuator may be formed by laminating a plurality of thin plate-shaped unit piezoelectric elements. This is because the displacement in the thickness direction generated in the unit piezoelectric element is taken out as large as possible.

FIG. 9A is a perspective view showing the appearance of a piezoelectric transducer having a plurality of piezoelectric elements of the above-described unit laminated. The piezoelectric transducer 100 has a thickness of 100 μm.
The electrode 10 is formed over the entire surface of the piezoelectric element 101 in units of about m.
2 and a plurality of these are laminated and bonded, and every other electrode 102 between the piezoelectric elements 101 of each unit is placed every other one in FIG.
As shown in the figure, the connections 103 and 104 are used to form a positive electrode and a negative electrode. When a voltage is applied to the positive electrode and the negative electrode, displacement occurs due to expansion and contraction in the thickness direction, so that the generated displacement is transmitted to the driven member by appropriate means to drive or position the driven member. .

In the piezoelectric transducer having the above-described structure, the displacement direction of the element is limited to one direction. Therefore, in order to generate a complicated movement such as an elliptical movement, as described below, a structure in which a plurality of piezoelectric elements are combined is used. Things were used.

For example, as shown in a perspective view (a) and a plan view (b) of a vibrator 120 shown in FIG. 10, a thin piezoelectric element 122
Is a vibrator in which a plurality of laminated piezoelectric elements 123 are attached to the upper surface of a quadrangular prism. By combining flexural vibration by the piezoelectric element 122 on the side surface and longitudinal vibration by the piezoelectric element 123 on the upper surface, the vibrator The elliptical motion is generated in the action member 124 on the top surface.

Further, as shown in a perspective view of the vibrator 130 shown in FIG. 11, four piezoelectric elements 132 to 135 formed in a column shape by laminating a plurality of sheets on a base 131 are bonded and fixed. The elastic body 1 is placed on the piezoelectric elements 132 to 135.
The vibrating body 36 is fixed, and the four columnar piezoelectric elements 132 to 135 are driven by sinusoidal signals having different phases, so that the action member 137 on the top surface of the elastic body 136 is formed.
To generate an elliptical motion.

In addition, there has been proposed a device in which a piezoelectric element for bending vibration and a piezoelectric element for longitudinal vibration are arranged in series to form a vibrator in a columnar shape to generate an elliptical motion.

[0009]

As described above, in order to perform a complex motion such as an elliptical motion, a configuration in which a plurality of piezoelectric elements are combined is employed. Not only is it difficult, for example, in the vibrator having the configuration shown in FIG. 11, the displacement of the four piezoelectric elements is different.
Since the piezoelectric elements 132 to 135 are bonded and fixed to one elastic body 136, there is an inconvenience that the bonded fixing portion is easily peeled off.

A vibrator having a configuration in which a piezoelectric element for flexural vibration and a piezoelectric element for longitudinal vibration are arranged in series has disadvantages such as variations in assembly accuracy and strength. It is an object of the present invention to provide a piezoelectric transducer which has solved the above-mentioned problems, and an actuator using the piezoelectric transducer.

[0011]

According to a first aspect of the present invention, there is provided a thin plate-shaped piezoelectric element having a plurality of mutually independent electrodes formed on its surface, and the electrode positions thereof coincide with each other in the laminating direction. A piezoelectric conversion element characterized in that the piezoelectric conversion element is configured by stacking a plurality of layers in such a manner.

[0012] The plurality of electrodes formed on the surface of the piezoelectric element of the unit are arranged point-symmetrically with respect to the center of the piezoelectric element of the unit.

Further, the electrodes of the piezoelectric element of the plurality of stacked units constitute a drive electrode unit by an electrode group having the same position in the stacking direction, and a plurality of mutually independent drive electrode units are formed. Connected.

According to a fourth aspect of the present invention, there is provided a thin plate-shaped piezoelectric element having a plurality of mutually independent electrodes formed on a surface thereof.
A piezoelectric conversion element formed by stacking a plurality of piezoelectric conversion elements so that the electrode positions are aligned in the stacking direction; an operation member fixed to a top end of the piezoelectric conversion element in the stacking direction; An actuator using a piezoelectric conversion element comprising a driving member.

The plurality of electrodes of the piezoelectric transducer are arranged point-symmetrically with respect to the center of the unit piezoelectric element, and among the electrodes of the plurality of unit piezoelectric elements stacked in the stacking direction. A drive electrode unit is formed by an electrode group having the same position, and is connected so that a plurality of mutually independent drive electrode units are formed.

By applying alternating voltages having different phases to a plurality of mutually independent drive electrode units of the piezoelectric transducer, a rotational motion about three axes can be generated in the driven member.

[0017]

Embodiments of the present invention will be described below.

[Structure of Piezoelectric Conversion Element] First, the structure of a piezoelectric conversion element according to an embodiment of the present invention will be described. FIG. 1 is a perspective view illustrating the configuration of a piezoelectric conversion element 10. The piezoelectric conversion element 10 has a plurality of unit piezoelectric elements 11, and in the illustrated configuration, six piezoelectric elements 11a, 11b, 11c, 11d, 11
e and 11f are laminated. Unit piezoelectric element 11
Is a thin plate-shaped piezoelectric element made of piezoelectric ceramics containing, for example, PZT (PbZrO ₃ .PbTiO ₃ ) as a main component, and electrodes described later are formed on the surface thereof by a method such as vapor deposition. Note that the configuration shown in FIG. 1 has six laminated sheets, but this is an example, and any number of sheets necessary to obtain a desired driving force can be laminated. In addition, 1
Reference numeral 3 denotes a base, and 14 denotes a protective film.

The unit piezoelectric elements 11a, 11b, 11c,
The surfaces of 11d, 11e, and 11f are each divided into four to form four electrodes 12p, 12q, 12r, and 12s. These four electrodes are arranged so as to be point-symmetric with respect to the center of the unit piezoelectric element.

The piezoelectric element 11f located at the end when stacked is provided with four electrodes 12p,
When 12q, 12r, and 12s are formed, and a plurality of the piezoelectric elements 11a, 11b, 11c, 11d, and 11e of these units are laminated so that the non-electrode forming surface of each unit faces the electrode forming surface of another unit of the piezoelectric element, Piezoelectric element 11 located on the top surface
a, a piezoelectric element 11f located at the lowermost surface, and a piezoelectric conversion element stacked in a state where four electrodes 12p, 12q, 12r, and 12s are arranged between the respective piezoelectric elements 11b, 11c, 11d, and 11e. 10 are configured.

Here, the piezoelectric element 11 of the laminated unit
a, 11b, 11c, 11d and 11e are displaced by an electric field generated when a voltage is applied to the respective electrodes on both surfaces, and are displaced in the same direction.
It is assumed that the piezoelectric elements are stacked so that the polarization directions of the piezoelectric elements are alternated.

The piezoelectric elements 11a and 11 of the laminated unit
For each of the four electrodes 12p, 12q, 12r, and 12s formed and arranged between b, 11c, 11d, 11e, and 11f, every other drive signal line 15a, 15b,
15c, 15d and drive signal lines 16a, 16b, 16
c, 16d.

FIG. 2 shows a piezoelectric unit 11a of a stacked unit.
FIG. 13 is a front view illustrating a connection state of a drive signal line to electrodes 12p, 12q, 12r, and 12s formed and arranged between 11b, 11c, 11d, 11e, and 11f.
It is the front view seen from the direction where 2p and 12q end surface are exposed.

The electrode 12p on the upper surface of the piezoelectric element 11a, 11c, 11e and the electrode 12p on the lower surface of the piezoelectric element 11f are connected to the drive signal line 15a, and the piezoelectric elements 11b, 11d,
The electrode 12p on the upper surface of 11f is connected to the drive signal line 16a. The electrodes 12q on the upper surfaces of the piezoelectric elements 11a, 11c, and 11e and the electrodes 12q on the lower surface of the piezoelectric elements 11f are connected to the drive signal lines 15b, and the piezoelectric elements 11b, 11d,
The electrode 12q on the upper surface of 11f is connected to the drive signal line 16b.

Although not shown in FIG. 2, the electrodes 12 on the upper surfaces of the piezoelectric elements 11a, 11c and 11e are formed in the same manner as above.
The electrode r on the lower surface of the piezoelectric element 11f is connected to the drive signal line 15c, and the electrode 12r on the upper surface of the piezoelectric elements 11b, 11d, and 11f is connected to the drive signal line 16c. Also, the electrode 12 on the upper surface of the piezoelectric elements 11a, 11c, 11e
and the electrode 12s on the lower surface of the piezoelectric element 11f is connected to the drive signal line 15d, and the electrode 12s on the upper surface of the piezoelectric elements 11b, 11d, 11f is connected to the drive signal line 16d.

As described above, the electrodes of the piezoelectric element of a plurality of stacked units are connected to the first drive electrode unit by the electrode group 12p (connected to the drive signal lines 15a and 16a) whose positions match in the stacking direction. Is configured. Similarly,
The electrode groups 12q (connected to the driving signal lines 15b and 16b), 12r (connected to the driving signal lines 15c and 16c), and 12s (connected to the driving signal lines 15d and 16d) whose positions match in the stacking direction. By the second,
Third and fourth drive electrode units are configured.

Next, the operation will be described. Drive signal line 1
5a and 16a, between the drive signal lines 15b and 16b, between the drive signal lines 15c and 16c, and between the drive signal lines 15d and 16c.
d to supply a DC drive voltage to the first drive electrode unit 1
When the 2p to fourth driving electrode units 12s are driven, the piezoelectric conversion element 10 as a whole expands and contracts (or contracts).
Occurs.

As a result, a driven member (not shown) connected to the piezoelectric transducer 10 can be linearly moved in a predetermined direction.

Further, the first drive electrode units 12p to 4th
When a DC drive voltage is supplied to any one, or two, or three of the drive electrode units 12s to drive them, extension displacement (or contraction displacement) occurs only in the driven piezoelectric element of the drive electrode unit. Therefore, the piezoelectric conversion element 10 is partially distorted.

For example, in the configuration shown in FIGS. 1 and 2, a DC drive voltage is applied between the drive signal line 15a and the drive signal line 16a and between the drive signal line 15b and the drive signal line 16b to perform the first drive. The electrode unit 12p and the second drive electrode unit 1
When 2q is driven, the first and second drive electrode units 12
Since extension displacement occurs in p and 12q and extension displacement does not occur in the third and fourth drive electrode units 12r and 12s,
As a whole, the piezoelectric conversion element 10 is curved with the first and second drive electrode units 12p and 12q being extended sides.

When an AC voltage is applied to the first drive electrode unit 12p to the fourth drive electrode unit 12s, expansion and contraction displacement occurs in each drive electrode unit. First drive electrode unit 12p
By shifting the phase of the AC voltage applied to the fourth drive electrode unit 12s, a rotational motion can be generated at the tip of the piezoelectric conversion element 10.

[Structure of Actuator] FIG. 3 is a perspective view showing the structure of an actuator using the above-mentioned piezoelectric transducer. The actuator 20 includes a spherical driven body 21 and a driven body 21. A holding ring 22 for rotatably holding, a piezoelectric transducer 10 having the above-described configuration, an action member 23 having a spherical tip fixed to the tip of the piezoelectric transducer 10,
It is composed of a push-up member such as a spring (not shown) for bringing the spherical tip portion of the action member 23 into frictional contact with the driven body 21 at a predetermined contact pressure F. Reference numeral 25 denotes an arm implanted in the driven body 21.

Each drive electrode unit 12p of the piezoelectric transducer 10
When the actuating member 23 fixed to the tip is displaced by applying a drive signal to the driven members 21 to 12s, this displacement is transmitted to the driven body 21. That is, when the action member 23 is displaced in the left-right direction in FIG. 3, the driven body 21 that is in frictional contact with the spherical tip portion also rotates in the left-right direction, and the action member 23 moves in the front-rear direction (the direction ), The driven body 21 also rotates in the front-rear direction. When the operating member 23 is displaced in the vertical direction in FIG.
1 is also displaced in the vertical direction.

When drive signals having different phases are applied to the respective drive electrode units 12p to 12s of the piezoelectric conversion element 10 to generate a rotational displacement in the working member 23 fixed to the tip, the driven body 21 becomes three-dimensional. It can be rotated to any angle on the coordinates.

FIG. 4 is a diagram for explaining the state of the movement of the driven body 21 in the case where the rotational movement is generated around the horizontal axis (the axis perpendicular to the paper surface in FIG. 4) with respect to the driven body 21. FIG.
FIG. 4 is a diagram illustrating a drive signal applied to each drive electrode unit of the piezoelectric conversion element 10.

The arrangement of the respective electrodes of the piezoelectric transducer 10 is the same as that shown in FIGS. 1 and 2. In FIG. 4, the drive electrode unit 12 p is provided on the left side and the drive electrode unit 12 s is provided on the rear side.
It is assumed that there is a drive electrode unit 12q on the right side and a drive electrode unit 12r on the rear side.

Now, two sine-wave drive voltages (1) and (2) having phases different by 90 ° as shown in FIG. 5 are generated, and the sine-wave drive voltage (1) is applied to the drive electrode units 12p and 12s. When a sine wave drive voltage (2) advanced by 90 ° in phase is applied to the drive electrode units 12q and 12r,
The displacement of the piezoelectric element in the p and 12s portions and the displacement of the piezoelectric element in the drive electrode units 12p and 12s advanced by 90 ° from this are combined, and the piezoelectric conversion is performed on a plane parallel to the paper surface shown in FIG. A vibration tilting to the left and right and a stretching vibration in the vertical direction are generated in the element 10, and a rotating motion of an elliptical locus is generated in the working member 23 at the free end of the piezoelectric conversion element 10. At this time,
The rotation direction of the rotation of the elliptical locus is clockwise.

When the driven body 21 is brought into contact with the operating member 23, the upper half of the rotational movement of the elliptical trajectory (in FIG.
At the time when the moving member 3 moves upward, the operating member 23 and the driven body 21 come into contact with each other and the rotational motion is transmitted to the driven body 21, but the lower half of the elliptical locus (in FIG. Member 2
At the time when 3 moves downward), the operating member 23 and the driven body 21 are in a non-contact state, and the rotational motion is not transmitted to the driven body 21.

For this reason, the driven body 21 is driven only during the upper half of the rotational movement of the elliptical locus which rotates clockwise, so that the driven body 21 is placed on a plane parallel to the plane of FIG. It will be driven to rotate counterclockwise. Driven body 2
To drive 1 clockwise, drive electrode units 12p and 1
Sinusoidal wave drive voltage (2) is applied to 2s, and drive electrode unit 1
Sine wave drive voltage (1) may be applied to 2q and 12r.

In order to drive the driven body 21 in a counterclockwise direction on a plane perpendicular to the paper surface shown in FIG.
A sine wave drive voltage (1) is applied to p and 12q, and a sine wave drive voltage (2) is applied to the drive electrode units 12s and 12r. To drive in the opposite direction, a sine wave drive voltage (2) may be applied to the drive electrode units 12p and 12q, and a sine wave drive voltage (1) may be applied to the drive electrode units 12s and 12r.

In addition, the drive electrode units 12p and 12r,
And the driving electrode units 12q and 12s are respectively set, and the sine wave driving voltage (1) and the sine wave driving voltage (2) are applied to each pair, so that the driven body 21 is placed on the paper surface shown in FIG. It is also possible to drive diagonally.

FIGS. 6A and 6B show the driven member 21.
6A and 6B are diagrams illustrating a state of movement of the piezoelectric conversion element 10 and the driven body 21 when a rotational movement about a vertical axis is generated with respect to FIG. FIG. 6B is a front view of the driven member 21 in frictional contact with the operating member 23 in FIG. It is the top view seen from. FIG. 7 is a diagram illustrating a drive signal applied to the electrode of the piezoelectric conversion element 10.

The arrangement of the electrodes of the piezoelectric conversion element 10 is the same as that shown in FIGS. 1 and 2. In FIG. 4, the drive electrode unit 12 p is provided on the left side and the drive electrode unit 12 s is provided on the rear side.
There is a drive electrode unit 12q in front of the right side and a drive electrode unit 12r in the rear side. The arrangement order of the drive electrode units 12p, 12q, 12r, and 12s of the piezoelectric transducer 10 is as shown in FIG. Assume that they are arranged in a counterclockwise direction.

Now, as shown in FIG. 7, four sine-wave driving voltages (1), (2), (3), 90.degree.
(4) is generated, a sine wave drive voltage (1) is applied to the drive electrode unit 12p, a sine wave drive voltage (2) is applied to the drive electrode unit 12q, a sine wave drive voltage (3) is applied to the drive electrode unit 12r,
When a sine-wave drive voltage (4) is applied to the drive electrode unit 12s, the piezoelectric elements of the respective electrode portions of the piezoelectric conversion element 10 are sequentially displaced at time intervals corresponding to the phase delay, and the piezoelectric conversion element 10 shown in FIG. As shown in (a) and (b) of
Vibration tilting forward, backward, left and right is generated, and the action member 23 at the free end of the piezoelectric transducer 10 draws a circular motion, and its rotation direction is counterclockwise.

Accordingly, the driven body 21 in frictional contact with the working member 23 rotates clockwise as the working member 23 moves in a circular direction.

To reverse the direction of rotation of the driven body 21, the phase is delayed by 90 ° applied to each drive electrode unit.
The application order of the two sine wave drive voltages (1), (2), (3), and (4) is reversed, and the drive electrode units 12s, 12
The order may be r, 12q, 12p.

The rotation speed of the driven body 21 is controlled as follows.
It can be performed by controlling the voltage of the sine wave drive voltage applied to the electrodes.

FIG. 8 shows an example of an actuator drive circuit shown in FIGS. 6A and 6B. The drive circuit 30 includes a control unit 31 composed of a CPU and the like, and an oscillator for generating a sine wave drive voltage. 32, a first delay circuit 33 for delaying the phase of the sine wave drive voltage output from the oscillator 32 by 90 °,
A second delay circuit 34 for delaying the phase by 0 °, a third delay circuit 35 for delaying the phase by 270 °, a selector 36, and an amplifier 37 are provided.
Electrodes 12p, 12q, 12r, and 12s are connected.

The control unit 31 performs on / off control and oscillation frequency control of the oscillator 32, and receives an external input signal for instructing the rotation direction of the driven body 21 and receives the drive electrode unit 12.
The switching order of the selector 36 is controlled by determining the order of application of the sine wave drive voltages to a to 12s. Further, the control unit 31 determines an amplification degree of the amplifier 37 in response to an external input signal indicating a rotation speed of the driven body 21.

The oscillator 32 is a circuit that generates a sine-wave drive voltage serving as a reference for a drive signal under the control of the control unit 31. The reference sine wave driving voltage is input to the selector 36, and the first delay circuit 33 and the second delay circuit 3
4, input to the third delay circuit 35 and have a phase of 9
The sine wave drive voltage delayed by 0 °, 180 °, and 270 ° is input to the selector 36.

Under the control of the control unit 31, the selector 36 applies the sine wave drive voltages output from the oscillator 32 and the first to third delay circuits 33, 34 and 35 in the specified order to the drive electrode units 12p to 12p. This is a circuit for switching to output to 12r.

The amplifier 37 amplifies the amplitude of the sine wave drive voltage, and amplifies the input sine wave drive voltage with the amplification determined under the control of the control unit 31.

With the above configuration, the sine-wave drive voltage output from the oscillator 32 is converted into a total of four sine-wave drive voltages including a reference sine-wave drive voltage and three sine-wave drive voltages having phases shifted from each other. You. The four sine-wave drive voltages are assigned to the drive electrode units 12p to 12r to be applied by the selector 36, and are amplified by the amplifier 37 to a predetermined amplitude, and are applied to the drive electrode units 12p to 12r of the piezoelectric transducer 10. Applied.

The activator according to the embodiment of the present invention has been described above.
Although the configuration of the data has been described, its use will be briefly described. The above-described driven body 21 can perform a rotational motion about three axes (XYZ axes). Accordingly, the driven body 21
An artificial joint or the like can be configured by attaching an arm 25 to the armature, and an artificial vision that can move a line of sight in an arbitrary direction in a three-dimensional space when an imaging device is incorporated in the driven body 21. Can be configured. Further, when the driven body 21 is formed in a disk shape, a moving stage capable of moving and rotating within a plane can be formed.

In the embodiment of the present invention described above,
The piezoelectric element is divided into four to form four electrodes. However, the number of electrodes is not limited to this, and for example, a piezoelectric element may be divided into three to form three electrodes. In this case, the configuration of the drive circuit can be simplified because the number of electrodes is small.

[0056]

As described above, according to the present invention, a plurality of mutually independent electrodes are formed on the surface of a piezoelectric element in the form of a thin plate, and a plurality of piezoelectric elements in a unit in which these electrodes are formed are laminated to perform piezoelectric conversion. Since the element is configured, it is possible to perform complicated movements such as elliptical movement with a simpler configuration than the conventional piezoelectric conversion element, and a piezoelectric conversion element having high assembly accuracy and strength, and its piezoelectric conversion An actuator using the element can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of a piezoelectric conversion element according to an embodiment of the present invention.

FIG. 2 is a front view illustrating a connection state of drive signal lines of the piezoelectric transducer shown in FIG.

FIG. 3 is an Actie using the piezoelectric transducer shown in FIG. 1;
FIG.

FIG. 4 is a diagram illustrating a state of movement of a driven body when the driven body generates a rotational movement around a horizontal axis.

FIG. 5 is a diagram illustrating a drive signal applied to an electrode of a piezoelectric conversion element when a driven body is caused to rotate around a horizontal axis.

FIG. 6 is a diagram illustrating a state of movement of a piezoelectric conversion element and a driven body when a driven body generates a rotational motion about a vertical axis.

FIG. 7 is a diagram for explaining a drive signal applied to an electrode of a piezoelectric transducer when a driven body is caused to rotate around a vertical axis.

FIG. 8 is a block diagram showing an example of an actuator driving circuit.

FIG. 9 is a diagram illustrating a configuration of a conventional piezoelectric conversion element.

FIG. 10 is a view for explaining another example of the configuration of a conventional piezoelectric conversion element.

FIG. 11 is a perspective view illustrating another example of the configuration of a conventional piezoelectric conversion element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Piezoelectric conversion element 11a, 11b, 11c, 11d, 11e, 11f Unit piezoelectric element 12p, 12q, 12r, 12s Electrode (drive electrode unit) 13 Base 14 Protective film 15a, 15b, 15c, 15d Drive signal line 16a, 16b, 16c, 16d Drive signal line 20 Actuator 21 Driven body 22 Holding ring 23 Working member 25 Arm 30 Drive circuit 31 Control unit 32 Oscillator 33 Delay circuit 34 Delay circuit 35 Delay circuit 36 Selector 37 Amplifier

Claims (6)

[Claims] 1. A thin plate-shaped piezoelectric element having a plurality of mutually independent electrodes formed on a surface thereof, and a plurality of such piezoelectric elements are stacked so that their electrode positions are aligned in the stacking direction. Characteristic piezoelectric conversion element. 2. The piezoelectric device according to claim 1, wherein the plurality of electrodes formed on the surface of the piezoelectric element of the unit are arranged point-symmetrically with respect to the center of the piezoelectric element of the unit. Conversion element. 3. The electrode of the plurality of stacked piezoelectric elements constitutes a drive electrode unit by an electrode group having the same position in the stacking direction, and a plurality of mutually independent drive electrode units are formed. The piezoelectric conversion element according to claim 1, wherein the piezoelectric conversion element is connected in such a manner as described above. 4. A piezoelectric conversion device comprising a plurality of thin-plate-shaped piezoelectric elements each having a plurality of mutually independent electrodes formed on the surface thereof so that the electrode positions are aligned in the stacking direction. An actuator using a piezoelectric transducer, comprising: an element; an operating member fixed to a leading end of the piezoelectric transducer in the stacking direction; and a driven member that comes into frictional contact with the operating member.
Ta. 5. A plurality of electrodes of the piezoelectric transducer are arranged point-symmetrically with respect to the center of the unit piezoelectric element, and a plurality of electrodes of the unit piezoelectric element are stacked in the stacking direction. 5. An actuator using a piezoelectric transducer according to claim 4, wherein a drive electrode unit is constituted by an electrode group having the same position, and the drive electrode units are connected so as to form a plurality of mutually independent drive electrode units. -Ta. 6. A rotating member about three axes is generated in a driven member by applying AC voltages having different phases to a plurality of mutually independent driving electrode units of the piezoelectric conversion element. An actuator using the piezoelectric transducer according to claim 4.