JP3805644B2 - Piezoelectric actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric actuator used for, for example, an on / off switch, a changeover switch, and various sensors in a signal transmission circuit.
[0002]
[Prior art]
Conventionally, as an embodiment of the piezoelectric actuator, as shown in FIG. 8A, electrodes 92a and 92b are formed on both main surfaces of a thin plate-like piezoelectric plate 91, and polarization treatment is performed in the thickness direction of the piezoelectric plate 91. There is known a monomorph element 90 in which the piezoelectric element 93 is attached to one of main surfaces of a thin metal plate 94 having a predetermined thickness called a shim material. One end in the longitudinal direction of the monomorph element 90 is fixed at a predetermined position by using a fixing means 96.
[0003]
For example, the monomorph element 90 is configured such that when an electric field is applied in the same direction as the polarization direction of the piezoelectric plate 91, the thickness of the piezoelectric plate 91 increases due to the thickness-longitudinal displacement, and conversely, the piezoelectric plate due to the thickness-lateral displacement. A displacement is generated such that the longitudinal length of 91 is shortened. At this time, since the piezoelectric element 93 is affixed to the metal plate 94, a bending displacement occurs inside the arc on the piezoelectric element 93 side (FIG. 8B).
[0004]
Further, when an electric field is applied in a direction opposite to the polarization direction of the piezoelectric plate 91, a displacement occurs such that the thickness of the piezoelectric plate 91 becomes thin and the longitudinal length of the piezoelectric plate 91 extends. In this case, bending displacement occurs such that the piezoelectric element 93 side is outside the arc (FIG. 8C). Since the amount of displacement of the tip portion of the monomorph element 90 can be controlled by the voltage applied to the piezoelectric element 93, the monomorph element 90 is used for a positioning device or a switching element.
[0005]
[Problems to be solved by the invention]
However, in the conventional monomorph element 90, it has been common knowledge to use the metal plate 94 as a shim material. In this case, since the metal plate 94 is used as a conductive path for sending a signal for driving the piezoelectric element 93 to one electrode 92b formed on the piezoelectric element 93, the metal plate 94 is used as a drive signal for the piezoelectric element 93. circuitry for transmitting the different different signals (hereinafter, simply referred to as "the signal transmitting circuit") that is Ru impossible der used as part of a conductive path which constitutes the. That is, when the monomorph element 90 is used as a switching element, for example, it is necessary to operate another switch for turning on / off the signal transmission circuit using the displacement of the tip of the monomorph element 90. The device itself does not have a conductive path (conductive path) for signal transmission in the signal transmission circuit.
[0006]
The present invention has been made in view of the above-described problems of the prior art. The piezoelectric actuator itself is used as a part of the signal transmission circuit to perform on / off operation and switching operation of the signal transmission circuit. An object of the present invention is to provide a piezoelectric actuator that can be used.
[0007]
[Means for Solving the Problems]
That is, according to the present invention, a piezoelectric actuator that causes a bending displacement of the reinforcing plate by attaching a flat piezoelectric element to the reinforcing plate and applying a predetermined voltage to the piezoelectric element,
The portion of the reinforcing plate, a piezoelectric actuator, characterized in that used as the conductive path for transmitting different signals from the signal for driving the piezoelectric element, is provided.
[0008]
Further, according to the present invention, there is provided a piezoelectric actuator that causes a bending displacement in the reinforcing plate by attaching a plate-like piezoelectric element to the reinforcing plate and applying a predetermined voltage to the piezoelectric element,
The conductive path for transmitting different signals from the signal for driving the piezoelectric element is formed on a part of the reinforcing plate,
By controlling the flexion of the reinforcing plate, conductive path formed in the reinforcing plate, the to conduct circuit for transmitting different signals from the signal for driving the piezoelectric element, or the circuit cut or a piezoelectric actuator, characterized in that to conduct the circuit for transmitting a further signal different from the signal for a part to drive the piezoelectric elements of the circuit, is provided.
[0009]
In such a piezoelectric actuator of the present invention, the piezoelectric actuator itself functions as, for example, an on / off switch of a circuit ( signal transmission circuit ) for transmitting a signal different from a signal for driving the piezoelectric element. Therefore, it is not necessary to separately provide a switch that is turned on / off by a piezoelectric actuator that has been conventionally required. Thus, the circuit can be miniaturized. As the reinforcing plate, a laminate in which a resin and a metal are laminated is preferably used. In particular, a liquid crystal polymer resin is preferably used as the resin. By using such a laminate made of resin and metal as a reinforcing plate, it is possible to improve the vibration damping performance when driving the piezoelectric actuator, and when the piezoelectric actuator is used as an on / off switch, Chattering at the off contact can be prevented.
[0010]
It is preferable to use a reinforcing plate in which a conductor such as a metal foil is bonded to the front and back surfaces of the resin sheet. In this case, one of the conductors can be used as a conductive path for signal transmission. When a reinforcing plate having a structure in which a conductor is provided on each of the inside and front and back surfaces of the resin sheet is used, the piezoelectric element is attached to each of the front and back surfaces of the resin sheet, and is provided inside the resin sheet. The conductor can be used as a conductive path for signal transmission. If another conductive path is provided adjacent to the signal transmission path formed on the reinforcing plate, and the other conductive path is set to the ground potential, the signal transmission path formed on the reinforcing plate is shielded. (Shielded), and signal transmission can be performed more reliably.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking as an example a case where a piezoelectric actuator is used as an on / off switch or a changeover switch of a signal transmission circuit.
FIG. 1 is a cross-sectional view showing the structure of a monomorph element 10 which is an embodiment of the piezoelectric actuator of the present invention, and shows a state where the monomorph element 10 is not driven. FIG. 2 is a side view showing a state in which the monomorph element 10 shown in FIG. 1 is driven.
[0012]
The monomorph element 10 has a structure in which a piezoelectric element 12 is attached to the surface of a reinforcing plate 11, and the reinforcing plate 11 has a laminated structure in which metal foils (metal plates) 14a and 14b are attached to the front and back surfaces of a resin sheet 13, respectively. have. The piezoelectric element 12 has a structure in which electrodes 16a and 16b are formed on the front and back surfaces of a plate-like piezoelectric body 15 having a predetermined thickness. A fixing jig 19 is attached to one end of the reinforcing plate 11 in the longitudinal direction (X direction). When the monomorph element 10 is driven by applying a predetermined voltage to the piezoelectric element 12, the fixing jig 19 is attached. The other end that is not arranged is displaced in the substantially Z direction.
[0013]
As shown in FIG. 1, when the electrodes 16a and 16b are held at a ground potential (the electrode 16b has the same potential as the metal foil 14a as described later) and the monomorph element 10 is not driven, the metal foil 14b Is in contact with the contact member 17a connected (conductive) to the circuit B. Since the metal foil 14b is always connected to the circuit A, in the state shown in FIG. 1, the circuit A and the circuit B are connected via the metal foil 14b, and the metal foil 14b is connected to the circuit A and the circuit B. It functions as a conductive path.
[0014]
As shown in FIG. 2, when a predetermined DC voltage is applied between the electrodes 16a and 16b of the piezoelectric element 12, when the direction of polarization in the piezoelectric body 15 and the direction of the applied electric field coincide in the piezoelectric element 12, the piezoelectric element Since the element 12 contracts in the longitudinal direction due to the thickness-lateral effect, the entire monomorph element 10 is bent and displaced so that the tip of the reinforcing plate 11 moves to the piezoelectric element 12 side in the Z direction. Due to the bending displacement of the monomorph element 10, the metal foil 14b is separated from the contact member 17a, and the circuit A and the circuit B are disconnected.
[0015]
By bringing the electrodes 16a and 16b to the same potential from the state of FIG. 2 and returning the monomorph element 10 to the state shown in FIG. 1, the metal foil 14b and the contact member 17a are brought into contact with each other to connect the circuit A and the circuit B. it can. As described above, the monomorph element 10 itself functions as a switch that performs connection / disconnection operation (ON / OFF operation) between the circuit A and the circuit B.
[0016]
Conventionally, the circuit was turned on / off by operating an on / off switch provided separately from the monomorph element according to the displacement of the monomorph element. However, by using the monomorph element 10, on / off is separately performed. There is no need to provide a switch, and a simple circuit configuration can be provided, and a small circuit can be configured at low cost.
[0017]
Next, components of the monomorph element 10 will be described. Examples of the material of the resin sheet 13 include a liquid crystal polymer resin. When the liquid crystal polymer resin is used, it is possible to bond the metal foils 14a and 14b by thermal fusion, and therefore, compared with the case where the metal foils 14a and 14b are bonded to the resin sheet 13 using an adhesive. Then, the resin sheet 13 and the metal foils 14a and 14b are not easily separated, and the reliability is improved.
[0018]
As the metal foils 14a and 14b, copper foil is preferably used, but aluminum foil or the like may be used. The thickness of the metal foils 14a and 14b can be about 10 to 100 μm, for example. A laminate sheet in which a copper foil is bonded to a liquid crystal polymer resin sheet is easily available as a so-called printed wiring board. Therefore, by using such a laminate sheet, production costs are reduced and productivity is improved. be able to.
[0019]
By using the reinforcing plate 11 of the monomorph element 10 having a structure in which materials having different elastic moduli of resin and metal are laminated in the thickness direction, the occurrence of resonance vibration is suppressed and the vibration damping property is enhanced, and the drive response Can be improved. When the vibration damping property of the monomorph element 10 is improved in this way, when the monomorph element 10 is driven, the occurrence of chattering phenomenon in which the metal foil 14b intermittently contacts the contact member 17a can be suppressed, and the metal foil 14b. And the contact state of the contact member 17a can be stabilized.
[0020]
As the piezoelectric body 15, lead zirconate titanate-based piezoelectric ceramics having high piezoelectric characteristics is preferably used. The electrodes 16a and 16b can be formed by printing an electrode paste such as a silver paste on the front and back surfaces of a plate-like piezoelectric ceramic using a screen printing method or the like, and baking it. The thickness of the electrodes 16a and 16b is generally 2 to 8 μm when the screen printing method is used.
[0021]
A resin adhesive is used for attaching the piezoelectric element 12 to the reinforcing plate 11, and this resin adhesive may be insulative or conductive. When an insulating adhesive is used, the thickness of the adhesive layer is reduced so that the electrode 16b and the metal foil 14a are in contact with each other. Thus, the electrode 16b and the metal foil 14a are electrically connected. 1 and 2 do not show an adhesive layer formed by this resin adhesive. Adhesion of the piezoelectric element 12 to the reinforcing plate 11 is performed in consideration of the direction of polarization after the piezoelectric body 15 in the piezoelectric element 12 is polarized.
[0022]
Next, another embodiment of the piezoelectric actuator of the present invention will be described. FIG. 3 is an explanatory diagram showing a mode in which the metal foil 14b and the contact member 17a are more reliably contacted when the monomorph element 10 shown in FIG. 1 is used. A predetermined pressing force is applied to the tip of the monomorph element 10 where the metal foil 14b is in contact with the contact member 17a so as to press the reinforcing plate 11 against the contact member 17a from the metal foil 14a side. And the contact state of the contact member 17a can be stabilized.
[0023]
If the magnitude of the pressing force is made smaller than the generated force of the monomorph element 10 so that the metal foil 14b is separated from the contact member 17a when the monomorph element 10 is driven, the pressing force is changed. There is no need to provide a mechanism. Examples of the member that applies the pressing force include a spring and a heavy stone. Further, the pressing force can be changed using an air cylinder or the like in accordance with the driving of the monomorph element 10.
[0024]
A predetermined pattern can be formed on the metal foil 14 b in the monomorph element 10. 4A is a diagram of the monomorph element 10a in which the conductive path 21 and the two shield wires 22a and 22b are formed on the back surface of the resin sheet 13 with the conductive path 21 interposed therebetween, as viewed from the back surface side of the resin sheet 13. FIG. It is. The support member 19 side of the conductive path 21 is always connected to the circuit A, and the contact member 17a side of the conductive path 21 is in contact with the contact member 17a connected to the circuit B or according to the driving state of the monomorph element 10a. Separation is possible. The shield lines 22a and 22b are held at the ground potential. As a result, the conductive path 21 is less susceptible to noise and the like due to electromagnetic waves from the outside, and the accuracy of signal transmission between the circuit A and the circuit B is improved.
[0025]
4B shows the monomorph element 10b in which the conductive path 23a / 23b and the two shield wires 24a / 24b are formed on the back surface of the resin sheet 13 with the conductive path 23a / 23b interposed therebetween. The support member 19 side of the conductive paths 23a and 23b is always connected to the circuit A, and the contact member side of the conductive paths 23a and 23b is in accordance with the driving state of the monomorph element 10b. The contact members 17a and 17a ′ that are separately connected to the circuit B can be contacted or separated from each other.
[0026]
Also in the monomorph element 10b, like the monomorph element 10a, by holding the shield wires 24a and 24b at the ground potential, the conductive paths 23a and 23b are hardly affected by noise or the like due to electromagnetic waves from the outside. And circuit B can be accurately transmitted. It is more preferable to further provide a shield wire between the conductive paths 23a and 23b and hold this shield wire at the ground potential. The conductive path 23a is used for an on / off operation between the circuit A and the circuit B, but the conductive path 23b is used for another circuit, for example, an on / off operation between the circuit C and the circuit D. It can also be.
[0027]
The patterns of the conductive paths 21 and the like shown in FIGS. 4A and 4B can be easily formed by masking a predetermined position of the metal plate 14b constituting the monomorph element 10 and performing an etching process, for example. .
[0028]
FIG. 5 is a cross-sectional view showing a schematic structure of a bimorph element 30 which is still another embodiment of the piezoelectric actuator of the present invention. The bimorph element 30 includes a reinforcing plate 31 and piezoelectric elements 32a and 32b attached to the front and back surfaces of the reinforcing plate 31, and one end thereof is held by a holding member 19a. The reinforcing plate 31 has a laminated structure in which a metal foil 34 is sandwiched between resin sheets 33a and 33b, a metal foil 35a is bonded to the surface of the resin sheet 33a, and a metal foil 35b is bonded to the surface of the resin sheet 33b.
[0029]
At the end of the resin sheet 33b in the X direction, through holes 36a and 36b, in which metal is filled or whose inner surface is coated with metal, are formed, and are electrically connected to the metal foil 34 through the through hole 36a. The metal foil 37a to be electrically connected to the metal foil 34 through the through hole 36b is bonded to the surface of the resin sheet 33b. The metal foils 37a and 37b are insulated from the metal foil 35b.
[0030]
The reinforcing plate 31 includes, for example, a printed wiring board in which metal foil 35b is bonded to a resin sheet 33b and through holes 36a and 36b filled with metal are formed at predetermined positions, and the metal foil 35a is bonded to the resin sheet 33a. It can be manufactured by sandwiching the metal foil 34 between the combined printed wiring boards and thermally fusing the resin sheets 33a and 33b and the metal foil 34 together.
[0031]
The piezoelectric elements 32a and 32b have the same structure as the piezoelectric element 12 previously shown in FIG. 1, but the detailed structure is omitted in FIG. FIG. 5 shows a state in which the metal foil 37b is in contact with the contact member 17a. In the bimorph element 30, for example, a voltage is applied so that the piezoelectric body constituting the piezoelectric element 32a contracts in the X direction. Sometimes, if a voltage is applied so that the piezoelectric body constituting the piezoelectric element 32b extends in the X direction, the bimorph element 30 can be bent and displaced so that the metal foil 37b is separated from the contact member 17a. Thus, the bimorph element 30 can be operated as an on / off switch between the circuit A and the circuit B.
[0032]
FIG. 6 shows a metal foil that has a through hole 36c in which the end portion of the resin sheet 33a is filled with metal or whose inner surface is coated with metal in the bimorph element 30 shown in FIG. 5, and is electrically connected to the through hole 36c. 37c is a schematic cross-sectional view of the bimorph element 30a bonded to the surface of the resin sheet 33a. A contact member 17a connected to the circuit B is disposed on the metal foil 37b side, and a contact member 17b connected to the circuit C is disposed on the metal foil 37c side.
[0033]
In the state shown in FIG. 6, the bimorph element 30a is not driven, and the circuit A is not connected to either the circuit B or the circuit C. When the bimorph element 30a is bent toward the contact member 17a from the state shown in FIG. 6, the contact member 17a and the metal foil 37b come into contact with each other, and the circuit A and the circuit B can be conducted. On the other hand, when the bimorph element 30a is bent toward the contact member 17b from the state shown in FIG. 6, the contact member 17b and the metal foil 37c come into contact with each other, and the circuit A and the circuit C can be connected. Thus, the bimorph element 30a can be used as a changeover switch.
[0034]
When the bimorph element 30a is not driven, the metal foil 37b is always in contact with the contact member 17a, and the bimorph element 30a is displaced by a predetermined amount so that the metal foil 37b and the contact member 17a The circuit A to the circuit C can be made independent by separating the metal foil 37c and the contact member 17b from each other. In this case, by further displacing the bimorph element 30a by a predetermined amount, the metal foil 37c can be brought into contact with the contact member 17b to connect the circuit A and the circuit C.
[0035]
FIG. 7 is an explanatory view showing the structure of a bimorph element 30b which is another embodiment of the bimorph element, and FIG. 7A is a plan view showing the structure of a reinforcing plate 41 used in the bimorph element 30b. 7 (b) is a cross-sectional view of the Z-X plane of the bimorph element 30b taken along line AA in FIG. 7 (a), and FIG. 7 (c) is a ZX view of the bimorph element 30b taken along line BB in FIG. 7 (a). FIG. 7C is a cross-sectional view of the Z-X plane of the bimorph element 30b taken along line CC in FIG. 7A.
[0036]
The reinforcing plate 41 constituting the bimorph element 30b has a structure in which two metal foils 43a and 43b that are not electrically connected to each other are sandwiched between two resin sheets 42a and 42b. The resin sheet 42a has through holes 44a and 44b that are electrically connected to the metal foil 43a at the end in the X direction, and the resin sheet 42b has through holes 45a and 45b that are electrically connected to the metal foil 43b in the X direction. Is formed.
[0037]
The through hole 44a is electrically connected to the metal foil 46a provided on the surface of the resin sheet 42a, the through hole 44b is electrically connected to the metal foil 46b provided on the surface of the resin sheet 42a, and the metal foil 46a is always connected to the circuit A. It is in a connected state. The through hole 45a is electrically connected to the metal foil 47a provided on the surface of the resin sheet 42b, the through hole 45b is electrically connected to the metal foil 47b provided on the surface of the resin sheet 42b, and the metal foil 47a is connected to the circuit D. And always connected.
[0038]
A metal foil 48a insulated from the metal foils 46a and 46b is bonded to the surface of the resin sheet 42a, and a metal foil 48b insulated from the metal foils 47a and 47b is bonded to the surface of the resin sheet 42b. The piezoelectric elements 49a and 49b are attached to the metal foils 48a and 48b, respectively.
[0039]
In the bimorph element 30b having such a structure, for example, when the bimorph element 30b is not driven, the circuit A and the circuit B can be held in a state where they are not connected to different circuits. When the bimorph element 30b is driven to bend toward the piezoelectric element 49a, the metal foil 46b can contact the contact member 17a connected to the circuit B (see FIG. 7B). ), The circuit A and the circuit B can be connected. On the other hand, when the bimorph element 30b is driven to bend toward the piezoelectric element 49b, the metal foil 47b can contact the contact member 17b connected to the circuit C (FIG. 7 (d)). By doing so, the circuit C and the circuit D can be connected.
[0040]
Although the embodiment of the piezoelectric actuator of the present invention has been described above, the present invention is not limited to the above embodiment. For example, it goes without saying that the shield wire formed in the monomorph elements 10a and 10b can be applied to the bimorph element 30 as well. Further, like the monomorph elements 10a and 10b by forming a predetermined pattern on the metal foil 14b of the monomorph element 10, the predetermined pattern is formed on the metal foil 34 in the bimorph element 30 to increase the number of circuits that perform the on / off operation. It is also possible.
[0041]
Furthermore, although the case where the piezoelectric actuator was used as a piezoelectric actuator on / off switch has been described in the above embodiment, the piezoelectric actuator of the present invention can also be used as various sensors. For example, when the monomorph element 10 is brought into the state shown in FIG. 2 by receiving a predetermined external force from the state shown in FIG. 1, the circuit A and the circuit B are disconnected, so that this circuit disconnection is detected. Thus, the monomorph element 10 can be used as an external force detection sensor. In this case, it is possible to measure the magnitude of the external force acting on the monomorph element 10 by measuring the electric charge generated in the piezoelectric element 12, and the number of parts can be reduced. Can be realized.
[0042]
【The invention's effect】
As described above, according to the piezoelectric actuator of the present invention, since the piezoelectric actuator itself functions as, for example, an on / off switch of a signal transmission circuit, an on / off operation is performed by a piezoelectric actuator that has been conventionally required. There is no need to provide a separate switch. In this way, the effect that the signal transmission circuit can be miniaturized can be obtained. Further, by using a laminated body in which a resin and a metal are laminated as the reinforcing plate, it is possible to improve the vibration damping performance when driving the piezoelectric actuator. That is, when the piezoelectric actuator is used as an on / off switch, chattering at the on / off contact is prevented, and the reliability of the on / off operation can be improved. Furthermore, by using a printed wiring board as the reinforcing plate, it is possible to provide a piezoelectric actuator that is inexpensive and excellent in reliability. The piezoelectric actuator of the present invention can also be used as a sensor, and a small sensor can be realized.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a schematic structure of a monomorph element which is an embodiment of a piezoelectric actuator of the present invention.
FIG. 2 is a side view showing a state where the monomorph element shown in FIG. 1 is driven.
3 is a cross-sectional view showing another arrangement of the monomorph element shown in FIG. 1. FIG.
FIG. 4 is an explanatory view of the structure of a monomorph element which is another embodiment of the piezoelectric actuator of the present invention, viewed from the back side of the reinforcing plate.
FIG. 5 is a cross-sectional view showing the structure of a bimorph element which is still another embodiment of the piezoelectric actuator of the present invention.
FIG. 6 is a cross-sectional view showing the structure of a bimorph element which is still another embodiment of the piezoelectric actuator of the present invention.
FIG. 7 is a plan view of a reinforcing plate used in the bimorph element and a cross-sectional view showing the structure of the bimorph element using the reinforcing plate.
FIG. 8 is a cross-sectional view showing the structure of a conventional monomorph element.
[Explanation of symbols]
Monomorph element 11, 31, 41; Reinforcing plate 12, 32a, 32b, 49a, 49b; Piezoelectric element 13, 33a, 33b, 42a, 42b; Resin sheet 14a, 14b, 34, 35a, 35b, 37a, 37b, 37c, 43a, 43b, 46a, 46b, 47a, 47b, 48a, 48b; metal foil 15; piezoelectric bodies 16a, 16b; electrodes 17a, 17a ', 17b; contact members 19, 19a; Conductor paths 22a, 22b, 24a, 24b; shield wires 30, 30a, 30b; bimorph elements 36a, 36b, 36c, 44a, 44b, 45a, 45b; through hole 90; monomorph element 91; piezoelectric plate 92a 92b; electrode 93; piezoelectric element 94; metal plate 96; fixing means

Claims (7)

A piezoelectric actuator that affixes a plate-like piezoelectric element to a reinforcing plate and causes a bending displacement in the reinforcing plate by applying a predetermined voltage to the piezoelectric element,
A piezoelectric actuator wherein a portion of the reinforcing plate, characterized in that it is used as a conductive path for transmitting different signals from the signal for driving the piezoelectric element. A piezoelectric actuator that affixes a plate-like piezoelectric element to a reinforcing plate and causes a bending displacement in the reinforcing plate by applying a predetermined voltage to the piezoelectric element,
The conductive path for transmitting different signals from the signal for driving the piezoelectric element is formed on a part of the reinforcing plate,
By controlling the flexion of the reinforcing plate, conductive path formed in the reinforcing plate, the to conduct circuit for transmitting different signals from the signal for driving the piezoelectric element, or the circuit cut or a piezoelectric actuator, characterized in that to conduct the circuit for transmitting a further signal different from the signal for a part to drive the piezoelectric elements of the circuit.   The piezoelectric actuator according to claim 1, wherein the reinforcing plate is a laminated body made of a resin and a metal.   The piezoelectric actuator according to claim 3, wherein the resin is a liquid crystal polymer resin. The reinforcing plate has a structure in which a conductor is provided on each of the front and back surfaces of a single resin sheet, and one of the conductors conducts electricity to transmit a signal different from a signal for driving the piezoelectric element. The piezoelectric actuator according to claim 3 or 4, wherein the piezoelectric actuator is used as a path. The reinforcing plate has a structure in which conductors are respectively provided on the inside and front and back surfaces of the resin sheet, the piezoelectric elements are respectively attached to the front and back surfaces of the resin sheet, and the conductors provided inside the resin sheet are the piezoelectric actuator according to claim 3 or claim 4, characterized in that is used as conductive path for transmitting different signals from the signal for driving the piezoelectric element. Formed in said reinforcing plate, said another conductive path so as to be adjacent to a conductive path for transmitting a signal different from the signal for driving the piezoelectric elements are provided,
With ground potential said another conductive path, wherein, wherein a conductive path for transmitting different signals from the signal for driving the piezoelectric element formed on said reinforcing plate is shielded The piezoelectric actuator according to any one of claims 2 to 6.

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