JP2001339965A - Piezo actuator - Google Patents

Abstract

(57) [Problem] To provide a piezoelectric actuator which can perform a bending operation and a complicated attitude control with higher accuracy than a hybrid structure using a monolithic piezoelectric material. SOLUTION: A plurality of electrodes 2a to 2i, 3 each having a shape, a size, and a relative position for performing a desired operation are respectively provided on opposing surfaces of a plate-shaped piezoelectric material 1 having a monolithic structure.
a to 3i, and switch circuits 4a to 4i, 5a capable of connecting the plurality of electrodes to the DC power source 6 independently of each other.
To 5i, by controlling the multiple electrodes independently to the positive electrode or the negative electrode of the DC power supply, or by performing control not to connect to any of them, so that the expansion and contraction operation and the bending in the arrangement area of the multiple electrodes are performed. Perform all or part of the operation and the rotation operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric actuator which is used for moving or positioning an object or changing the course of a fluid by causing a small spatial displacement with a high degree of freedom. The present invention relates to a piezoelectric actuator having a monolithic structure.

[Summary of the Invention] The present invention relates to a monolithic piezoelectric actuator having a structure that enables a more accurate bending operation without using any of the unimorph structure and the bimorph structure, and performs a complicated operation. Instead of having a hybrid structure, a large number of electrodes having a shape, size, and relative position for performing a desired operation are provided on opposing surfaces of a monolithic plate-like piezoelectric material with a small number of parts so that the operation can be performed. By arranging these electrodes and connecting them to a switch circuit that can be independently connected to a DC power supply and changing the state of the electric field generated during polarization and driving, all or part of the stretching, bending, and rotating operations can be performed with accuracy. It controls the shape and posture of the piezoelectric material.

[0003]

2. Description of the Related Art A piezoelectric actuator using the inverse piezoelectric effect of a piezoelectric material is said to be unsuitable as an actuator having a large displacement due to its own strength and displacement generation efficiency. It is applied to the purpose requiring a small displacement.

In the reverse piezoelectric effect, for example, when distortion occurs in a direction extending perpendicularly to the electrode, the volume of the piezoelectric material does not change, so that a phenomenon of contraction occurs in the lateral direction. In particular, many of them make use of the displacement caused by the expansion and contraction. That is,
The amount of displacement is increased by utilizing the expansion and contraction as they are, or by laminating a piezoelectric material to which an electrode for imparting a similar function is added.

The stacked type has been applied in various fields because it has a large generating force and the displacement can be controlled by the number of layers. Usually, it is designed to use displacement in the direction of elongation, but there is also one that is capable of performing a bending operation (for example, Japanese Patent Application Laid-Open No. H5-261061). Japanese Patent Laid-Open No. 5-
The actuator described in Japanese Patent No. 261061 is a stack of disk-shaped unimorph-type elements. Focusing on one layer, a large number of divided electrodes are arranged on a disk, and a voltage is applied to each pair of electrodes to generate a distortion. The distortion is integrated by stacking, and the bending operation is performed. Is possible.

On the other hand, unimorph type and bimorph type actuators are known for the purpose of bending operation or fertility operation (rotating operation). The unimorph type has a structure in which one piezoelectric material having symmetrical electrodes on the front and back surfaces is laminated on one elastic body by bonding or the like. In the bimorph type, an elastic body is disposed so as to be sandwiched between two piezoelectric materials having symmetrical electrodes on the front and back surfaces for the purpose of increasing the amount of bending.

Japanese Unexamined Patent Publication No. Hei 5-318373 proposes an actuator having a high degree of freedom by applying a unimorph type or bimorph type actuator. Japanese Patent Application Laid-Open No. H11-206149 proposes an integrated actuator which does not require an assembling step such as assembly or bonding required for a unimorph type or bimorph type actuator. The actuator described in Japanese Patent Application Laid-Open No. 11-206149 uses a comb-shaped electrode to use the vertical effect of the inverse piezoelectric effect, and further applies a substrate that controls expansion and contraction by the normal inverse piezoelectric effect to promote bending. It has a laminated structure by printing, thick film / thin film technology, etc.

In applications where a large generated force or displacement is not required, the generated force or displacement of only one layer constituting the laminate may be sufficient. For example, there is an example in which a space is provided in a structure, two hinges are arranged, and the structure is displaced in the lateral direction (X axis) using the expansion and contraction operation of each of the two hinges.

At this time, if the generated force and displacement of an actuator made of a single plate-like or bulk-like piezoelectric material are sufficient in terms of performance, such a piezoelectric material is processed to only the necessary parts. A monolithic structure in which the electrodes are arranged is an excellent process in that the number of assembly and wiring steps is reduced, the manufacturing accuracy is reduced, and the cost is reduced.

[0010] Further, all sensors and actuators using a piezoelectric material have a hysteresis between applied voltage and displacement or strain. Japanese Patent Application Laid-Open No. 5-56667 discloses a technique in which electrodes arranged on a piezoelectric material are subdivided. In particular, a method for stably obtaining a fine-precision displacement is proposed by avoiding use in a low-voltage region where displacement characteristics are unstable and causes a displacement error. In this case, the electrodes are finely divided so as to achieve both accuracy and displacement with respect to displacement in the direction of expansion and contraction.

[0011]

As described above, conventionally, a unimorph or bimorph type actuator using an elastic body in combination with a piezoelectric actuator to perform a bending operation or a twisting operation (rotating operation) is mainly used. . However, since these have a hybrid structure using a plurality of materials such as a piezoelectric material and an elastic body, the cost is higher than a piezoelectric actuator having a monolithic structure using only a single piezoelectric material.

Also, the number of electrodes that can be independently controlled is as small as two or two or more, and the displacement and bending operation angle are controlled only by the voltage applied to these electrodes.
It is difficult to perform complicated attitude control.

An object of the present invention is to provide a piezoelectric actuator which can perform a bending operation and a complicated attitude control with higher precision than those of a hybrid structure using a plate-like piezoelectric material having a monolithic structure.

[0014]

In order to achieve the above object, a piezoelectric actuator according to the present invention is provided with a shape and a size for performing a desired operation on each of opposing surfaces of a plate-shaped piezoelectric material having a monolithic structure. A switch circuit that arranges a large number of electrodes having relative positions and that can connect the large number of electrodes to a DC power source independently, and connects the large number of electrodes to a positive electrode or a negative electrode of the DC power source independently Alternatively, by performing control not to connect to any of them, all or a part of the expansion / contraction operation, the bending operation, and the rotation operation is performed in the arrangement region of the plurality of electrodes.

In the above-mentioned piezoelectric actuator of the present invention, the plate-like piezoelectric material is formed in a rectangular shape, and the plurality of electrodes are arranged in an array over substantially the entire front or back surface or a specific region. I have.

Further, in the piezoelectric actuator according to the present invention, the rectangular plate-shaped piezoelectric material has a fixed portion at one end and the plurality of electrodes arranged in an array on the front and back surfaces at the other end. It is characterized by:

Further, in the above-described piezoelectric actuator of the present invention, the plate-shaped piezoelectric material is formed in a disk shape, and the plurality of electrodes are concentrically arranged on the front and back surfaces.

[0018]

FIG. 1 is a configuration diagram of a piezoelectric actuator according to an embodiment of the present invention. As shown in FIG. 1, this piezoelectric actuator has a large number of electrodes 2a to 2i and 3a on the front and back surfaces of a monolithic piezoelectric plate 1.
To 3i are arranged symmetrically in an array, and the respective electrodes are individually connected to the DC power supply 6 via the corresponding switches 4a to 4i and 5a to 5i. In the following description, the electrodes 2a to 2i may be referred to as an electrode group 2 and the electrodes 3a to 3i may be referred to as an electrode group 3 as appropriate.

These electrodes are formed on the front and back surfaces of the piezoelectric plate 1 by any one or a plurality of means of dip coating, spray coating, spin coating, printing, spaking, vapor deposition, plating, electrophoresis, and photolithographic dicing.・ Laser processing ・ Polishing ・ Grinding ・ Application ・
It is shaped into a plurality of arrays by either ashing or a plurality of means.

As can be understood from the various embodiments described below, the piezoelectric plate member 1 can be formed into a rectangular plate shape or a disk shape according to the purpose. The relative positions of the electrodes in the array may be in any positional relationship as long as they are not in electrical contact with each other. Any arrangement can be made according to the purpose of the operation.

In the above configuration, the electrodes in an array form
Through the switches 4a to 4i and 5a to 5i, each is independently connected to the positive electrode or the negative electrode of the DC power supply 6, or not connected to any of them.

Therefore, by independently turning on and off these switches, the connection state and the polarity of the electrodes are independently controlled, and the polarization generated between the electrode connected to the positive electrode and the electrode connected to the negative electrode is controlled. By changing the direction and magnitude of the electric field at the time, an arbitrary polarization state can be created.

Further, by independently turning on and off the switches connected to the array-shaped electrodes, the connection state and the polarity of the array-shaped electrodes can be controlled independently, and the positive electrode and the negative electrode can be controlled independently. The direction and magnitude of the electric field at the time of driving generated between them are varied, and as a result, the degree of expansion and contraction due to the strain generated inside the piezoelectric plate material 1 having a monolithic structure is adjusted,
An extension operation, a single or multiple bending operation, and a single or multiple rotation operation can be performed.

Next, the results of confirming the above operation are shown in FIGS.
This will be described with reference to FIG. FIG. 2 is a side view showing a specific example of dimensions of a piezoelectric actuator manufactured for confirming operation. FIG. 3 is a perspective view showing a specific appearance and an example of dimensions. As shown in FIGS. 2 and 3, the piezoelectric plate 1 was formed in a rectangular shape having a length of 15 mm, a width of 2 mm, and a thickness of 0.5 mm. The section of 5.5 mm from the left end in FIG. 2 of the piezoelectric plate material 1 is the measurement fixing portion 1a, and the section of 9.5 mm from there to the right end is the electrode forming region 1b. In the electrode forming region 1b, a length of 2 m is provided on the front surface and the back surface of the remaining 8.5 mm region having a space of 0.5 mm at both ends.
Chromium gold electrodes (electrode group 2 and electrode group 3) having a thickness of m, a width of 800 μm, and a thickness of 400 nm were symmetrically produced at a pitch of 1 mm.

FIG. 4 is an explanatory view of the formation of the electric field intensity distribution inside the piezoelectric plate 1. Note that the electric field intensity distribution in the piezoelectric plate 1 is actually composed of the composition distribution in the small region of the piezoelectric plate 1, the piezoelectric constant, the polarization intensity, the polarization direction, the electric field intensity distribution during operation, the operation electric field direction, and the like. Although it is complicated because there is a complicated correlation between them, it is simplified in FIG.

In FIG. 4, first, all the switches 4a
To 4i and 5a to 5i are closed to make the electrode 2a
To 2i are connected to the positive electrode of the DC power supply 6, the electrodes 3a to 3i are connected to the negative electrode of the DC power supply 6, and 600 V DC is applied between the electrode group 2 and the electrode group 30 for 30 seconds, and 1 kV /
The piezoelectric plate 1 was subjected to a polarization treatment by generating a DC electric field of 1 mm. Therefore, a polarization electric field (initial polarization electric field) 7 perpendicular to the front and back surfaces and directed from the front surface to the back surface is provided in the piezoelectric plate 1.
Is thought to occur.

Thereafter, the switch is switched so that only the selected one of the electrode groups 2 and 3 can be energized, and 200 V / 200 V is applied between the selected electrode group 2 and the electrode group 3 in the same direction as the polarization. The operation was attempted by applying an electric field of mm.
At this time, it is considered that an electric field intensity distribution state different from that at the time of polarization has occurred.

For example, as shown in FIG. 4, in the electrode group 2, the switches 4a to 4c are closed to connect the electrodes 2a to 2c to the positive electrode of the DC power source 6, and in the electrode group 3, the switch 5b is closed and the electrode 3b is Connected to the negative electrode of the power supply 6, 200 V / mm
Was applied. In this case, as shown in FIG. 4, it is considered that an electric field (operating electric field) from three electrodes 2a to 2c to one electrode 3b is generated.

FIG. 5 is an explanatory diagram of displacement measurement. As shown in FIG. 5, the 5 mm long fixing portion 1a having no electrodes disposed thereon was fixed to the clamp 10 and the displacement of the tip on the opposite side was measured. A bending operation was caused by the electrode selection pattern, and a displacement of 3.0 μm in the vertical direction was confirmed at the tip.

FIG. 6 is an explanatory diagram of the attitude control operation. Similarly to FIG. 5, when the fixed portion 1a at the time of measurement having a length of 5 mm where no electrodes are arranged is fixed and the posture control is performed to translate the tip on the opposite side in parallel, the displacement is 1.7 μm. confirmed. For measuring the displacement, a laser microscope and a surface roughness measuring instrument were modified and used.

FIG. 7 is an explanatory diagram of the rotation operation. (A)
Is a non-operation state diagram, and (b) is an operation state diagram. In FIG. 7B, the electrodes are not shown. As in FIG. 5, a portion having a length of 5 mm where no electrode is provided is fixed (FIG. 7).
(A)). By the electrode selection pattern, a bending operation occurred, and a rotating operation could be performed on the opposite end portion (FIG. 7B).

Example 1 FIG. 8 is a diagram showing an application example (Example 1) of the piezoelectric actuator according to the present embodiment. In a disk recording / reproducing apparatus using an HDD or a slider-type optical head, an actuator that realizes tracking and space control (focusing) with high accuracy while maintaining a posture is required.

FIG. 8 shows an example in which the disk device is used as an actuator for adjusting the height of a space between the disk and a rotating disk while maintaining the attitude of the slider.

In FIG. 8, an attitude control spacing control actuator 20 is a piezoelectric actuator according to the present embodiment, and the portion where no electrode is disposed is the support 2.
1 and the electrode forming region on the opposite side is extended and held on the disk 22. A slider 23 is fixed to the lower surface of the tip portion of the electrode forming region.

The disk 22 is a disk rotation motor 24
8A, the slider 24 is supported in parallel with the surface of the disk 22 with a space 25 above the disk 22, as shown in FIG. 8A. Have been.

In this state, by causing the attitude control spacing control actuator 20 to perform the above-described vertical displacement operation and attitude control operation, the slider 24 is moved to the position shown in FIG.
As shown in FIG.
The space 26 having a smaller interval than the interval of 5 can be positioned parallel to the surface of the disk 22 and maintained.

As described above, the piezoelectric actuator according to the present embodiment can be used as an actuator for moving and positioning a sensing device.

Example 2 FIG. 9 is a diagram showing an application example (Example 2) of the piezoelectric actuator according to the present embodiment. FIG. 9 shows an example of use as a tracking actuator capable of controlling the amount of protrusion of a magnetic head used in a digital VTR for broadcasting or the like.

In FIG. 9A, a magnetic head 32 slides on a magnetic tape 31 to be driven and travels, and recording and reproducing of signals are performed. The magnetic head 32 is attached to the tip of a tracking actuator 33 inside the VTR drum 30 as shown in the enlarged view.
The magnetic tape 31 can protrude from the peripheral surface of the magnetic tape 31 and slide on the magnetic tape 31.

In FIG. 9B, in the VTR, the track on which the normal recording and reproduction of magnetic information is normally performed by the magnetic head 32 should be straight like the track 35, but actually, the track 36 Often bent. If this bend becomes large with respect to the width of the track, undesirable phenomena such as overwriting on the track written immediately before at the time of recording, or the inability to correctly read the recorded signal at the time of reproduction occur.

Controlling the position of the magnetic head 32 to the correct track position in order to prevent this is called tracking. By sensing the bending of the track at the time of recording or reproduction and feeding back the information, the tracking is performed. A method of actively controlling the position of the head 32 is called dynamic tracking.

Conventionally, a bimorph type piezoelectric actuator is often used for this position control. In a VTR with a dynamic tracking function (FIG. 9A),
The position control of the magnetic head 32 is performed so as to correct the tracking deviation of about several μm (FIG. 9B).

At this time, conventionally, the attitude control is performed so that the contact angle between the magnetic tape 31 and the magnetic head 32 does not greatly change from the normal state. However, since the entire length of the tracking actuator 33 does not change, for example, FIG.
As shown in (c), depending on the degree of attitude control, a state (a) indicated by a broken line where the magnetic head 32 can contact the magnetic tape 31 and a state (b) indicated by a solid line where the magnetic head 32 cannot contact the magnetic tape 31 occur. A space 37 is generated between the magnetic head 32. It is said that such a space 37 leads to a deterioration in the SN ratio when recording / reproducing a magnetic signal.

Therefore, since the piezoelectric actuator according to the present embodiment can also expand and contract, if the piezoelectric actuator according to the present embodiment is used as the tracking actuator 33, as shown in FIG. Even if the position of the magnetic head 32 shifts from the state shown by the broken line (c) to the state shown by the solid line (d), the magnetic head 32 can be brought into contact with the magnetic tape 31 in both states.

That is, by using the piezoelectric actuator according to the present embodiment, in addition to the tracking operation and the attitude control operation, an operation (head protrusion amount control) for preventing the generation of this space can be performed. It is possible to prevent deterioration of the SN ratio due to generation of a space between the head and the head.

<< Embodiment 3 >> FIG. 10 is a diagram showing an application example (embodiment 3) of the piezoelectric actuator according to the present embodiment. In FIG. 10, AFM (Atomic Force Microscopy)
It is shown that the present invention can be applied to a manipulator of a device that requires high-precision fine positioning in order to observe a fine region. FIG. 10A is a configuration diagram of a conventional AFM sensing unit. FIG. 10B is a configuration diagram of the cantilever / manipulator according to the present embodiment.

In FIG. 10A, the AFM sensing unit includes a cantilever 4 supported by a manipulator 41.
A sensor portion 43 called a tip is attached to the tip of the second. In the AFM sensing unit, the manipulator 41 can accurately move the cantilever 42 in the X-axis direction 44, the Y-axis direction 45, and the Z-axis direction 46, thereby sensing an observation target 47 in a specific area. At present, the manipulator 41 is a bimorph type or a unimorph type.

In FIG. 10B, a cantilever 51 according to the present embodiment is formed by forming a monolithic piezoelectric plate material into a rectangular plate shape, and an electrode group 52 is formed on the front and back surfaces at a substantially intermediate portion in the longitudinal direction. Have been. One end in the longitudinal direction is a fixed portion 53, and the above-mentioned sensor portion 43 is attached to the other end which is a free end.

By applying the voltage to the electrode group 52 as described above, the cantilever 51 can be accurately moved in the X-axis direction 54, the Y-axis direction 55, and the Z-axis direction 56. The sensing of the object 47 can be performed.

By adopting a structure combining the cantilever and the manipulator in this way, an actuator which has a small number of parts, is inexpensive, and can easily perform a scanning operation can be realized. Although not shown, the piezoelectric actuator of the present embodiment can of course be used as the manipulator 41 for operating the conventional cantilever 42 described above.

Fourth Embodiment FIG. 11 is a diagram showing an application example (a fourth embodiment) of the piezoelectric actuator according to the present embodiment. FIG. 11 shows that a relay switch can be configured by using both the expansion and contraction operation and the bending operation of the piezoelectric actuator according to the present embodiment.
(A) is a block diagram, (b) (c) is an operation explanatory diagram.

In FIG. 11A, electrodes 62 formed on both sides of a rectangular piezoelectric plate member 61 are connected to a DC power supply via a wiring 63 via a switch circuit (not shown). That is, the piezoelectric actuator itself according to the present embodiment shown in FIG. 1 is directly configured. In FIG. 1, the lower end is a fixed portion, and the formation region of the illustrated electrode 62 is a free end.

A switch electrode 64 is attached to the free end of the piezoelectric plate 61. This switch electrode 6
4, a large number of relay contacts 65 a to 65 (c) are vertically arranged along the piezoelectric plate 61, and a large number of relay contacts 65 a to 65 (c) are also vertically arranged symmetrically on the right side. ing. The switch electrode 64 is connected to a signal line 66 to be switched.

With this configuration, the electrodes 62 of the piezoelectric plate 61
When the formed portion performs the expansion and contraction operation and the bending operation, the switch electrode 64 displaces the position in the up-down direction and the left-right direction to selectively contact with many relay contacts (65a to 65f) and conduct with the signal line 66. Can be done.

For example, in the illustrated example, the switch electrode 64
Is located at the position where the relay contacts 65 (b) and (e) are arranged, and as shown in FIG. 11 (b), only the piezoelectric plate 61 is caused to perform a right-turning operation without expanding / contracting operation. Can be brought into contact with the relay contact 65 (e). Similarly, the switch electrode 64 can be brought into contact with the relay contact 65 (b) only by causing the piezoelectric plate member 61 to perform a leftward bending operation without any expansion / contraction operation.

As shown in FIG. 11C, the piezoelectric plate member 61 is caused to perform a contracting operation and a turning operation to the left,
The switch electrode 64 can be brought into contact with the relay contact 65 (c). Similarly, the switch electrode 64 can be brought into contact with the relay contact 65f by causing the piezoelectric plate member 61 to perform a contracting operation and a right-turning operation.

Although not shown, the piezoelectric plate member 61 is caused to perform an extension operation and bend to the left, so that the switch electrode 64 is brought into contact with the relay contact 65a and an operation to bend to the right is performed. The switch electrode 64 can be brought into contact with the relay contact 65 (d).

As described above, by the expansion and contraction operation and the bending operation of one piezoelectric actuator, a large number of relay contacts constituting the relay switch can be selected and individually operated.

Example 5 FIG. 12 is a diagram showing an application example (Example 5) of the piezoelectric actuator according to the present embodiment. FIG. 12 shows that a microvalve that adjusts the flow rate of fluid can be configured by utilizing the bending operation of the piezoelectric actuator according to the present embodiment. (A) is a block diagram, (b) is an operation explanatory diagram.

In FIG. 12A, a bending operation piezoelectric actuator 72 is disposed inside a housing 71. The housing 71 is provided with a fluid inlet 73 for taking in the fluid 75 on the upper right side, and a fluid outlet 74 for discharging the fluid 75 on the upper left side.

Next, the operation will be described. In FIG. 12B, the fluid discharge port 74 is closed by the bending operation actuator 72, and the fluid 75 is taken in from the fluid inlet 73 (S1). When the bending operation actuator 72 is flattened, the inside of the housing 71 is filled with the fluid 75 (S
2). When the bending operation is increased while closing the fluid inlet 73 with the bending operation actuator 72, the fluid 75 is discharged from the fluid discharge port 74 (S3). The principle of the microvalve can be applied to an injector and the like.

Embodiment 6 FIG. 13 is a diagram showing an application example (Example 6) of the piezoelectric actuator according to the present embodiment. FIG. 13 shows that a plurality of piezoelectric actuators according to the present embodiment can be used as a device for adjusting the force transmission efficiency of a fluid clutch by performing a waving operation like a wing. (A) is a perspective view showing a configuration,
(B) is a side sectional view showing the configuration, and (c) and (d) are operation explanatory diagrams.

13 (a) and 13 (b), a bending operation piezoelectric actuator 82 is arranged on the surface of an arbitrary structure 81 so as to be embedded in an array (5 × 2 in the illustrated example). Since each bending operation piezoelectric actuator 82 has electrodes formed on almost the entire front and back surfaces of a rectangular piezoelectric plate material, the bending operation is performed sequentially from one end to the other end, so that the piezoelectric actuator 82 is displaced in a wavy manner. Can be done.

When the bending operation piezoelectric actuator 82 is in a flat state, the fluid flowing on the surface of the structure 81 goes straight as indicated by a straight arrow 83, but as shown in FIGS. When the bending operation piezoelectric actuator 82 bends in a wave shape, the resistance of the structure 81 to the fluid increases, and the flow can be changed in a wave shape as indicated by a wavy arrow 84.

Although the above description is for the case where a plurality of bending operation piezoelectric actuators are used, the same operation can be performed by one bending operation piezoelectric actuator. This principle can also be used for a device that controls the flow rate and flow rate of a fluid such as air or water, or that gives buoyancy to a structure.

Example 7 FIG. 14 is a diagram showing an application example (Example 7) of the piezoelectric actuator according to the present embodiment. In FIG. 14, the piezoelectric actuators in which the electrodes are arranged concentrically are arranged in an array, and the height of the projections of each piezoelectric actuator is adjusted to obtain a point-diagram display device or a macro-texture (smooth or rough feeling). 3) A surface unevenness variable device applicable to a variable device is shown.
(A) is a perspective view showing a configuration, (b) is a side view showing a configuration, and (c) is an operation explanatory view.

14 (a) and 14 (b), a plurality of piezoelectric actuators (3 × 3 in the illustrated example) 92 arranged in an array on a base 91 are formed in a large number concentrically on the front and back surfaces of a disk-shaped piezoelectric plate material. Electrodes are arranged. On the upper surface touched by the hand, an insulating film 93 having a thickness enough to allow the protrusion to be recognized from above the base 91 and the piezoelectric actuator 92 for safety.
Is coated.

When a voltage is selectively applied to the electrode group to generate a distortion in the same manner as that generated by the rectangular plate-shaped piezoelectric actuator, the center of the disk-shaped piezoelectric actuator 92 may be pushed up or depressed. As a result, as shown in FIG.
Can occur.

By arranging the disk-shaped piezoelectric actuators 92 in an array at minute intervals, the apparent surface properties of the surface of the base 91 can be varied, and the friction coefficient changes macroscopically. This makes it possible to change the spatial frequency of the projections and change the expression of the surface sensation such as a slippery feeling or a rough feeling when rubbing with a hand or the like.

As described above, the present invention can be applied as a tactile display of a type that mainly changes the texture by artificially changing the surface properties such as unevenness and roughness of the material surface (a device for varying the coefficient of friction in a minute area). it can.

As described above, according to the present embodiment, the piezoelectric constant of the piezoelectric plate material, the mechanical structure of the piezoelectric plate material, the shape of the electrode, the size of the electrode, the arrangement position of the electrode, the electrode selection pattern for polarization, Voltage for polarization, electrode selection pattern for use,
By changing the voltage at the time of use, the electric field intensity distribution during operation can be changed, and the distortion can be controlled by the uneven distribution of this electric field intensity distribution, so that the monolithic piezoelectric actuator with a small number of parts expands and contracts accurately. And a bending / fertile operation can be realized, and a piezoelectric actuator that can be used for various various applications can be provided.

[0072]

As described above, according to the present invention,
The amount of expansion and contraction of one micro area can be determined by applying a binary control that applies a voltage that allows stable operation to the micro area with the multi-electrode method, so the expansion and contraction amount can be controlled more easily, and the accuracy can be improved. It is possible to provide a monolithic piezoelectric actuator that can bend and fertilize well.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a piezoelectric actuator according to an embodiment of the present invention.

FIG. 2 is a side view showing a specific example of dimensions of a piezoelectric actuator manufactured for checking operation.

FIG. 3 is a perspective view showing a specific appearance and an example of dimensions of the piezoelectric actuator produced above.

FIG. 4 is an explanatory diagram of electric field intensity distribution formation inside a piezoelectric plate material.

FIG. 5 is an explanatory diagram of displacement measurement.

FIG. 6 is an explanatory diagram of a posture control operation.

FIG. 7 is an explanatory diagram of a rotation operation. (A) is a non-operation state diagram, (b) is an operation state diagram.

FIG. 8 is a diagram showing an application example (Example 1) of the piezoelectric actuator according to the present embodiment.

FIG. 9 is a diagram showing an application example (Example 2) of the piezoelectric actuator according to the present embodiment. (A) is a diagram showing a main part of a VTR with a dynamic tracking function, (b) is an explanatory diagram of track deviation, (c) is an explanatory diagram of space generation by tracking, and (d) is a diagram of the piezoelectric actuator according to the present embodiment. It is explanatory drawing of the tracking operation | movement in the case of using, and the operation | movement which prevents the space generation.

FIG. 10 is a diagram showing an application example (Example 3) of the piezoelectric actuator according to the present embodiment. (A) shows a conventional AF
It is a block diagram of a M sensing part, (b) It is a block diagram of the cantilever and the manipulator by this Embodiment.

FIG. 11 is a diagram showing an application example (Example 4) of the piezoelectric actuator according to the present embodiment. (A) is a configuration diagram,
(B) and (c) are explanatory diagrams of the operation.

FIG. 12 is a diagram showing an application example (Example 5) of the piezoelectric actuator according to the present embodiment. (A) is a configuration diagram,
(B) is an operation explanatory diagram.

FIG. 13 is a diagram showing an application example (Example 6) of the piezoelectric actuator according to the present embodiment. (A) is a perspective view showing the configuration, (b) is a side sectional view showing the configuration, (c) and (d).
Is an operation explanatory diagram.

FIG. 14 is a diagram illustrating an application example (Example 7) of the piezoelectric actuator according to the present embodiment. (A) is a perspective view showing a configuration, (b) is a side view showing a configuration, and (c) is an operation explanatory view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Piezoelectric plate material 1a Fixed part at the time of measurement 1b Electrode formation area 2, 3 Electrode group 2a-2i, 3a-3i Electrode 4a-4i, 5a-5i Switch 6 DC power supply 7 Polarization electric field (initial polarization electric field) 10 Clamp 20 Attitude control Pacing control actuator 21 Post 22 Disk 23 Slider 24 Disk rotation motor 25, 26 Space 30 VTR drum 31 Magnetic tape 32 Magnetic head 33 Tracking actuator 35 Normal recording / reproduction track without bending 36 Bending causing tracking deviation Track 37 Space 41 Manipulator 42 Cantilever 43 Sensor unit (tip) 44 X-axis operation direction 45 Y-axis operation direction 46 Z-axis operation direction 47 Observation target 51 Cantilever 52 Electrode group 53 Fixed part 54 X-axis operation method 55 Y-axis operation direction 56 Z-axis operation direction 61 Piezoelectric plate material 62 Electrode 63 Wiring 64 Switch electrode 65 a to 65 f Relay contact constituting a relay switch 66 Signal line to be switched 71 Housing 72 Bending operation piezoelectric actuator 73 Fluid inlet 74 Fluid outlet 75 Fluid 81 Arbitrary structure 82 Bending operation piezoelectric actuator 83 Fluid flow before change 84 Changed fluid flow 91 Base 92 Discoid piezoelectric actuator 93 Surface coating 94 Micro projection

Claims (4)

[Claims] 1. A plurality of electrodes having a shape, a size, and a relative position for performing a desired operation are arranged on each of opposing surfaces of a plate-shaped piezoelectric material having a monolithic structure. By providing a switch circuit that can be independently connected to a DC power supply, by connecting the plurality of electrodes to the positive electrode or the negative electrode of the DC power supply independently, or by performing control not to connect to any of the plurality of electrodes, And performing all or a part of the expansion / contraction operation, the bending operation, and the rotation operation in the arrangement area of the piezoelectric actuator. 2. The piezoelectric actuator according to claim 1, wherein the plate-shaped piezoelectric material is formed in a rectangular shape, and the plurality of electrodes are arranged in an array on substantially the entire front or back surface or a specific region. A piezoelectric actuator, characterized in that: 3. The piezoelectric actuator according to claim 2, wherein one end of the rectangular plate-shaped piezoelectric material is a fixed portion,
The piezoelectric actuator, wherein the plurality of electrodes are arranged in an array on the front and back surfaces on the other end side. 4. The piezoelectric actuator according to claim 1, wherein the plate-shaped piezoelectric material is formed in a disk shape, and the plurality of electrodes are arranged concentrically on front and back surfaces. Piezo actuator.