JP4586501B2 - Piezoelectric actuator device - Google Patents

Description

  The present invention relates to a piezoelectric actuator device used for a micropump or the like.

As a conventional piezoelectric actuator device, a piezoelectric body in which a plurality of individual electrodes are formed and a piezoelectric body in which a common electrode is formed are alternately stacked, and the individual electrodes and the common electrodes that are aligned in the stacking direction pass through through holes. Are electrically connected to each other (for example, see Patent Document 1). In such a piezoelectric actuator device, a terminal electrode electrically connected to each of the individual electrode group and the common electrode group aligned in the stacking direction through a through hole is formed on the outermost piezoelectric body.
JP 2002-254634 A

  By the way, in the piezoelectric actuator device as described above, since the terminal electrode is provided for each individual electrode group aligned in the stacking direction, the electrical connection between the signal line and the terminal electrode for inputting the drive signal to the individual electrode is provided. There are as many connection points as the number of individual electrodes formed on the piezoelectric body. Therefore, as the integration of the individual electrodes increases, the electrical connection between the signal lines and the terminal electrodes may become complicated.

  Accordingly, the present invention has been made in view of such circumstances, and provides a piezoelectric actuator device that can reduce the number of electrical connection points with a signal line for inputting a drive signal. Objective.

In order to achieve the above object, a piezoelectric actuator device according to the present invention is a piezoelectric actuator device including an actuator unit, and the actuator unit is formed on a first piezoelectric body and one end surface of the first piezoelectric body. , A first drive electrode to which a drive signal is input, and a second drive electrode formed on the other end surface of the first piezoelectric body and facing the first drive electrode. A plurality of pairs of first drive electrodes and second drive electrodes are formed on the first piezoelectric body, and the first drive electrodes are integrally formed to form the first drive electrode body. The first drive electrode of the plurality of first drive electrode bodies is opposed to one second drive electrode, and the third piezoelectric body is laminated on the actuated body connection side of the actuator section. The third piezoelectric body has a first direction in the stacking direction. Wherein the ground electrode which covers the dynamic electrode and the second driving electrodes are formed.

In the actuator portion of this piezoelectric actuator device, a plurality of pairs of first and second drive electrodes facing each other are formed on the first piezoelectric body, and the first drive electrodes are integrally formed. Thus, the first drive electrode body is configured. For this reason, when a drive signal is input to the first drive electrode body, the drive signal is input to all of the first drive electrodes constituting the first drive electrode body. However, since the second drive electrode is opposed to each first drive electrode across the first piezoelectric body, a voltage is applied between the first drive electrode body and any second drive electrode. Then, the portion corresponding to the second drive electrode in the first piezoelectric body is displaced as an active portion (a portion in which distortion occurs due to the piezoelectric effect). Therefore, according to this piezoelectric actuator device, an electrical connection point with a signal line for inputting a drive signal may be ensured for each first drive electrode body. The number of electrical connection points can be reduced as compared with the case where the electrical connection points are ensured for each drive electrode. In addition, a third piezoelectric body is laminated on the actuating body connection side of the actuator unit, and a ground electrode that covers the first drive electrode and the second drive electrode in the lamination direction is provided on the third piezoelectric body. By being formed, an actuated body such as a micropump and the actuator portion can be electrically shielded to prevent the influence of electrical noise from the actuated body side.

  In addition, it is preferable that a plurality of actuator portions are two-dimensionally arranged, and the corresponding second drive electrodes are formed integrally between the actuator portions. As described above, since the corresponding second drive electrodes are integrally formed between the actuator portions, a voltage is applied to the second drive electrodes even when a plurality of actuator portions are two-dimensionally arranged. The number of electrical connection points with the signal line can be reduced.

  In addition, the actuator portions are preferably aligned in at least one direction. As a result, the actuator unit can be highly integrated. Furthermore, it is possible to easily realize a control in which an actuator unit is arbitrarily selected and a voltage is applied between the first drive electrode body and the second drive electrode.

  Further, it is preferable that the first piezoelectric body is integrally formed between the actuator portions. Thereby, size reduction of a piezoelectric actuator apparatus can be achieved.

  In addition, it is preferable that a plurality of actuator sections are stacked with the second piezoelectric body interposed therebetween so that each of the first drive electrode and the second drive electrode is aligned in the stacking direction. Thereby, a laminated piezoelectric actuator device can be easily configured.

  Further, the first drive electrode bodies aligned in the stacking direction are electrically connected via through holes, and the second drive electrode aligned in the stacking direction is electrically connected via through holes. It is preferable. Thus, since the first drive electrode bodies aligned in the stacking direction are electrically connected via the through holes, the first drive electrodes aligned in the stacking direction are electrically connected via the through holes. The number of through holes can be reduced as compared with the case where it is done.

  In addition, a fourth piezoelectric body is laminated on the circuit connection side of the actuator portion, and the first piezoelectric body electrically connected to the first drive electrode body via a through hole is stacked on the fourth piezoelectric body. It is preferable that a terminal electrode and a second terminal electrode electrically connected to the second drive electrode through a through hole are formed. Thereby, connection with a circuit is easily realizable. Furthermore, since the first terminal electrode is electrically connected to the first drive electrode body via the through hole, the first terminal electrode is electrically connected to each of the first drive electrodes via the through hole. The number of first terminal electrodes can be reduced compared to the case where the first terminal electrodes are connected.

  In addition, it is preferable to include a drive circuit that outputs a drive signal to the first drive electrode body, and a selector that selectively connects and disconnects the electrical connection between each of the second drive electrodes and the drive circuit. Thereby, the active part corresponding to the second drive electrode in the piezoelectric body can be arbitrarily displaced.

  According to the present invention, the number of electrical connection points with a signal line for inputting a drive signal can be reduced.

  Hereinafter, preferred embodiments of a piezoelectric actuator device according to the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or an equivalent part, and the overlapping description is abbreviate | omitted. Further, in this specification, terms such as “upper” and “lower” are based on the state shown in the drawings and are for convenience.

  As shown in FIG. 1, the piezoelectric actuator device 1 includes a piezoelectric actuator element 2. As shown in FIG. 2, the piezoelectric actuator element 2 is formed by alternately laminating piezoelectric bodies 4 on which individual electrodes 3 are formed and piezoelectric bodies 7 on which common electrodes 5 and 6 are formed, and further, terminal electrodes 11. The piezoelectric body 14 on which .about.13 is formed is laminated on the uppermost layer.

  Each of the piezoelectric bodies 4, 7, and 14 is made of, for example, a piezoelectric ceramic material mainly composed of lead zirconate titanate, and is formed in, for example, a rectangular thin plate shape. The individual electrodes 3 and the common electrodes 5 and 6 are made of a conductive material mainly composed of silver (Ag) and palladium (Pd), for example, and are patterned by screen printing. The same applies to each electrode described below except for the terminal electrodes 11 to 13.

  As shown in FIG. 3, a plurality of individual electrodes 3 are arranged in the longitudinal direction of the piezoelectric body 4 on the upper surface of the third, fifth, and seventh piezoelectric bodies 4 counted from the uppermost piezoelectric body 14. Four rows are formed in an aligned state. Each individual electrode 3 is formed in a rectangular shape, and is arranged so that its longitudinal direction is orthogonal to the longitudinal direction of the piezoelectric body 4.

  Among the individual electrodes 3 in the first row and the second row, the individual electrodes 3 aligned in the longitudinal direction are integrally formed via the connection portion 3a, and thereby the individual electrode body 15 is configured. . Similarly, among the individual electrodes 3 in the third row and the fourth row, the individual electrodes 3 aligned in the longitudinal direction are integrally formed via the connection portion 3a, whereby the individual electrode body 15 is configured. Has been. Each individual electrode body 15 is connected to a conductive member 20 (see FIGS. 7 to 9) in a through hole 16 formed in the piezoelectric body 4 immediately below the connection portion 3a.

  In order to increase the mounting density of the individual electrode bodies 15 on the upper surface of the piezoelectric body 4, the individual electrode bodies 15 constituted by the individual electrodes 3 in the first and second rows and the individual in the third and fourth rows The individual electrode bodies 15 constituted by the electrodes 3 are arranged alternately.

  Furthermore, a relay electrode 17 is formed on the upper surface of one end of the piezoelectric body 4 to electrically connect the common electrodes 5 of the piezoelectric body 7 positioned above and below. On the other hand, a relay electrode 18 is formed on the upper surface of the other end of the piezoelectric body 4 to electrically connect the common electrodes 6 of the piezoelectric body 7 positioned above and below. Each relay electrode 17, 18 is connected to a conductive member 20 in a through hole 16 formed in the piezoelectric body 4 immediately below it.

  As shown in FIG. 4, the seventh-layer piezoelectric body 4 has the third-layer and fifth-layer piezoelectric elements in that no through hole 16 is formed in the piezoelectric body 4 immediately below the individual electrode body 15. It is different from the body 4.

  Further, as shown in FIG. 5, on the upper surface of the second layer, the fourth layer, and the sixth layer of the piezoelectric body 7 counted from the uppermost piezoelectric body 14, as shown in FIG. A relay electrode 19 is formed so as to face each connection portion 3a of the piezoelectric body 4 in the thickness direction of the bodies 4, 7, and 14. Each relay electrode 19 is connected to a conductive member 20 in a through hole 16 formed in the piezoelectric body 7 immediately below the relay electrode 19.

  Further, a pair of common electrodes 5 and 6 are formed on the upper surface of the piezoelectric body 7. The common electrode 5 includes a main body portion 5a facing the individual electrodes 3 in the first row of the piezoelectric bodies 4 in the stacking direction, a main body portion 5b facing the individual electrodes 3 in the third row of the piezoelectric bodies 4 in the stacking direction, A connecting portion 5c facing the relay electrode 17 of the piezoelectric body 4 in the direction is integrally formed. The common electrode 5 is connected to the conductive member 20 in the through hole 16 formed in the piezoelectric body 7 immediately below the connection portion 5c.

  On the other hand, the common electrode 6 includes a main body 6a facing the second row of individual electrodes 3 in the stacking direction and a main body 6b facing the fourth row of individual electrodes 3 in the stacking direction. The connecting portion 6c facing the relay electrode 18 of the piezoelectric body 4 in the stacking direction is integrally formed. The common electrode 6 is connected to the conductive member 20 in the through hole 16 formed in the piezoelectric body 7 immediately below the connection portion 6c.

  Further, as shown in FIG. 6, the upper surface of the uppermost piezoelectric body 14 is opposed to each relay electrode 19, connection portion 5 c of the common electrode 5, and connection portion 6 c of the common electrode 6 in the stacking direction. A terminal electrode 11, a terminal electrode 12, and a terminal electrode 13 are formed on the substrate. Each of the terminal electrodes 11 to 13 is connected to a conductive member 20 in a through hole 16 formed in the piezoelectric body 14 immediately below.

  In addition, lead wires, such as FPC (flexible printed circuit board), are soldered to each terminal electrode 11-13. Therefore, in order to make it easy to put solder when soldering the lead wires, each of the terminal electrodes 11 to 13 is made of Ag having good solder wettability on a base electrode layer made of a conductive material mainly composed of Ag and Pd. Is formed by forming a surface electrode layer made of a conductive material containing as a main component.

  As shown in FIG. 7, three individual electrode bodies 15 and 3 are provided for each terminal electrode 11 in the uppermost layer by stacking the piezoelectric bodies 4, 7, and 14 having electrode patterns formed as described above. The relay electrodes 19 are aligned in the stacking direction, and the aligned electrodes 5, 11, 19 are electrically connected by the conductive member 20 in the through hole 16.

  For the uppermost terminal electrode 12, as shown in FIG. 8, three common electrodes 5 and three relay electrodes 17 are aligned in the stacking direction, and the aligned electrodes 5, 12, 17 are arranged. Are electrically connected by the conductive member 20 in the through hole 16. Similarly, the three common electrodes 6 and the three relay electrodes 18 are aligned in the stacking direction with respect to the uppermost terminal electrode 13, and the aligned electrodes 6, 13, 18 are arranged in the through hole 16. Electrical connection is made by the conductive member 20.

  In addition, in order to ensure electrical connection by the conductive member 20 in the through hole 16, the through holes 16 adjacent in the stacking direction are formed in the piezoelectric bodies 4, 7, and 14 so that their center lines are shifted from each other. Has been.

  As described above, in the piezoelectric actuator element 2, the two individual electrodes 3 are integrally formed to form the individual electrode body 15. Thereby, since the terminal electrode 11 for inputting a drive signal to the individual electrode 3 may be provided for each group of individual electrodes 15 aligned in the stacking direction, the terminal electrode for each group of individual electrodes 3 aligned in the stacking direction. Compared with the case where 11 is provided, the number of terminal electrodes 11 can be halved. In addition, if the individual electrode bodies 15 aligned in the stacking direction are electrically connected via the through holes 16, the individual electrodes 3 aligned in the stacking direction can be electrically connected. The number of through holes 16 can be halved as compared with the case where each group is electrically connected through the through holes 16. Therefore, according to the piezoelectric actuator element 2, the yield can be improved and the cost can be reduced.

  As shown in FIG. 1, the piezoelectric actuator device 1 includes a drive circuit 22 electrically connected to each terminal electrode 11 by a signal line L1, and terminal electrodes 12, 13 by signal lines L2 and L3, respectively. The selector 23 is electrically connected. The drive circuit 22 and the selector 23 are electrically connected by a signal line L4. Here, the signal line L4 is grounded.

  The drive circuit 22 outputs a drive signal to an arbitrary drive electrode body 5 through the signal line L 1 and the terminal electrode 11. The selector 23 has a switch function, and selectively connects and disconnects the electrical connection between the signal line L2 and the signal line L4 and the electrical connection between the signal line L3 and the signal line L4. . That is, the selector 23 selectively selects the electrical connection between the terminal electrode 12 and the common electrode 5 and the drive circuit 22 and the electrical connection between the terminal electrode 13 and the common electrode 6 and the drive circuit 22. Connect and disconnect.

  The piezoelectric actuator element 2 is driven as follows by the drive circuit 22 and the selector 23 configured as described above. As an example, a case where a portion (a part of the piezoelectric bodies 4 and 7) A sandwiched between the individual electrode 3 and the common electrode 6 aligned on the left side in FIG. 7 is displaced will be described.

  First, the drive circuit 22 outputs a drive signal to the terminal electrode 11 electrically connected to the individual electrode body 15 including the individual electrode 3 aligned on the left side in FIG. As a result, a drive signal is input to the individual electrodes 3 aligned on the left side in FIG. At this time, as shown in FIG. 1, the selector 23 cuts off the electrical connection between the signal line L2 and the signal line L4 and connects the electrical connection between the signal line L3 and the signal line L4. . Thereby, a voltage is applied between the individual electrode 3 and the common electrode 6 aligned on the left side in FIG. As described above, the electric field E is generated in the portion A sandwiched between the individual electrode 3 and the common electrode 6 aligned on the left side in FIG. 7, and the portion A is displaced as the active portion.

  By the way, as shown in FIG. 9, the piezoelectric actuator element 2 is formed on a piezoelectric body (first piezoelectric body) 7 and a lower surface (one end face) of the piezoelectric body 7, and two drive signals are inputted. An actuator unit having individual electrodes (first drive electrodes) 3 and common electrodes (second drive electrodes) 5 and 6 formed on the upper surface (the other end surface) of the piezoelectric body 7 and facing the individual electrodes 3. 25. In the actuator unit 25, the pair of the individual electrode 3 and the common electrode 5 facing each other and the pair of the individual electrode 3 and the common electrode 6 facing each other are formed on the piezoelectric body 7, and the individual electrode 3 is integrated. Thus, an individual electrode body (first drive electrode body) 15 is formed. Hereinafter, paying attention to the actuator unit 25, the effects of the piezoelectric actuator element 2 and the piezoelectric actuator device 1 will be described.

  First, when a drive signal is input to the individual electrode body 15, the drive signal is input to the two individual electrodes 3 constituting the individual electrode body 15. However, since the common electrodes 5 and 6 are opposed to each individual electrode 3 across the piezoelectric body 7, when a voltage is applied between the individual electrode body 15 and the common electrode 5 or the common electrode 6, the piezoelectric body 7, the portion corresponding to the common electrode 5 or the common electrode 6 to which the voltage is applied is displaced as the active portion. Therefore, according to the piezoelectric actuator element 2, an electrical connection point with the signal line L <b> 1 for inputting a drive signal only needs to be ensured for each individual electrode body 15, and therefore, for each individual electrode 3 constituting the individual electrode body 15. Compared with the case where the electrical connection points are secured, the number of the electrical connection points can be reduced.

  A plurality of actuator sections 25 are two-dimensionally arranged in the longitudinal direction of the piezoelectric body 7, and the common electrodes 5 and the common electrodes 6 are integrally formed between the actuator sections 25. ing. As described above, the common electrodes 5 and the common electrodes 6 are integrally formed between the actuator portions 25, so that even if a plurality of actuator portions 25 are two-dimensionally arranged, the common electrodes 5, 6 are arranged. It is possible to reduce the number of electrical connection points with the signal lines L2 and L3 for applying a voltage to. In addition, since the actuator unit 25 is aligned in the longitudinal direction of the piezoelectric body 7, the actuator unit 25 can be highly integrated, and the actuator unit 25 can be arbitrarily selected and shared with the individual electrode body 15. Control of applying a voltage between the electrode 5 or the common electrode 6 can be easily realized.

  In addition, since the piezoelectric body 7 is integrally formed between the two-dimensionally arranged actuator portions 25, the piezoelectric actuator element 2 can be reduced in size.

  Further, a plurality of actuator portions 25 are stacked with the piezoelectric body (second piezoelectric body) 4 sandwiched so that each of the individual electrodes 3 and the common electrodes 5 and 6 are aligned in the stacking direction, so that a stacked piezoelectric actuator element is formed. 2 can be configured easily.

  In addition, since the individual electrode bodies 15 aligned in the stacking direction are electrically connected through the through holes 16, the individual electrodes 3 aligned in the stacking direction are electrically connected through the through holes 16. In comparison, the number of through holes 16 can be reduced.

  An actuated body is attached to the lower surface of the piezoelectric actuator element 2, and a piezoelectric body (third piezoelectric body) 4 is laminated on the actuated body connection side of the lowermost actuator unit 25. Therefore, a piezoelectric body in which a ground electrode that covers the individual electrode 3 and the common electrodes 5 and 6 in the stacking direction (as viewed from the stacking direction) may be provided on the lower surface of the piezoelectric body 4. As a result, the actuated body and the actuator unit 25 can be electrically shielded to prevent transmission of electrical noise.

  A circuit such as an FPC is attached to the upper surface of the piezoelectric body 14 of the piezoelectric actuator element 2, and a piezoelectric body (fourth piezoelectric body) 14 is laminated on the circuit connection side of the uppermost actuator section 25. On the upper surface of the piezoelectric body 14, a terminal electrode (first terminal electrode) 11 electrically connected to the individual electrode body 15 through the through hole 16 and the common electrodes 5, 6 through the through hole 16. Terminal electrodes (second terminal electrodes) 12 and 13 electrically connected to each of these are formed. Thereby, connection with a circuit is easily realizable. Furthermore, since the terminal electrode 11 is electrically connected to the individual electrode body 15 via the through hole 16, the terminal electrode 11 is electrically connected to each of the individual electrodes 3 via the through hole 16. In comparison, the number of terminal electrodes 11 can be reduced.

  The present invention is not limited to the embodiment described above.

  For example, in the above embodiment, the individual electrode body 15 is configured by the two individual electrodes 3, but the individual electrode body 15 may be configured by three or more individual electrodes 3.

  In the above-described embodiment, the multilayered piezoelectric actuator element 2 is configured by laminating three layers of the actuator units 25 arranged two-dimensionally with the piezoelectric body 4 interposed therebetween. May be constituted by, for example, one actuator unit 25.

It is a block diagram of one Embodiment of the piezoelectric actuator apparatus which concerns on this invention. It is a disassembled perspective view of the piezoelectric actuator element of the piezoelectric actuator apparatus shown by FIG. FIG. 3 is a plan view of third and fifth piezoelectric bodies of the piezoelectric actuator element shown in FIG. 2. FIG. 3 is a plan view of a seventh layer piezoelectric body of the piezoelectric actuator element shown in FIG. 2. FIG. 3 is a plan view of second, fourth, and sixth layer piezoelectric bodies of the piezoelectric actuator element shown in FIG. 2. FIG. 3 is a plan view of the uppermost piezoelectric body of the piezoelectric actuator element shown in FIG. 2. It is a fragmentary sectional view of the piezoelectric actuator element along the VII-VII line shown in FIG. It is sectional drawing of the piezoelectric actuator element along the VIII-VIII line shown by FIG. It is a fragmentary sectional view of the piezoelectric actuator element along the VII-VII line shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Piezoelectric actuator apparatus, 3 ... Individual electrode (1st drive electrode), 4 ... Piezoelectric body (2nd piezoelectric material, 3rd piezoelectric material), 5, 6 ... Common electrode (2nd drive electrode), 7 ... Piezoelectric body (first piezoelectric body), 11 ... Terminal electrode (first terminal electrode), 12, 13 ... Terminal electrode (second terminal electrode), 14 ... Piezoelectric body (fourth piezoelectric body), DESCRIPTION OF SYMBOLS 15 ... Individual electrode body (1st drive electrode body), 16 ... Through-hole, 22 ... Drive circuit, 23 ... Selector, 25 ... Actuator part.

Claims (8)

A piezoelectric actuator device comprising an actuator unit,
The actuator part is
A first piezoelectric body;
A first drive electrode formed on one end surface of the first piezoelectric body and receiving a drive signal;
A second drive electrode formed on the other end face of the first piezoelectric body and facing the first drive electrode;
In the actuator section, a plurality of pairs of the first drive electrode and the second drive electrode facing each other are formed on the first piezoelectric body, and the first drive electrode is integrally formed. And the first drive electrode body is configured ,
The first drive electrode of a plurality of the first drive electrode bodies is opposed to one second drive electrode,
A third piezoelectric body is laminated on the actuating body connecting side of the actuator portion, and the third piezoelectric body has a ground covering the first drive electrode and the second drive electrode in the lamination direction. A piezoelectric actuator device having electrodes formed thereon .   2. The piezoelectric actuator device according to claim 1, wherein a plurality of the actuator parts are two-dimensionally arranged, and the corresponding second drive electrodes are integrally formed between the actuator parts.   The piezoelectric actuator device according to claim 2, wherein the actuator units are aligned in at least one direction.   4. The piezoelectric actuator device according to claim 2, wherein the first piezoelectric body is integrally formed between the actuator portions.   2. The actuator section, wherein a plurality of the first drive electrodes and the second drive electrodes are stacked with a second piezoelectric body interposed therebetween so that each of the first drive electrodes and the second drive electrodes is aligned in the stacking direction. 5. The piezoelectric actuator device according to claim 4.   The first drive electrode bodies aligned in the stacking direction are electrically connected via a through hole, and the second drive electrodes aligned in the stacking direction are electrically connected via a through hole. The piezoelectric actuator device according to claim 5. A fourth piezoelectric body is laminated on the circuit connection side of the actuator portion, and the first piezoelectric body electrically connected to the first drive electrode body through a through hole is connected to the fourth piezoelectric body. The terminal electrode of 1 and the 2nd terminal electrode electrically connected with the said 2nd drive electrode through the through hole are formed. The any one of Claims 1-6 characterized by the above-mentioned. Piezoelectric actuator device. A drive circuit for outputting a drive signal to the first drive electrode body;
Electrical connection selectively connected and the piezoelectric actuator device according to any one of claims 1-7, characterized in that it comprises a selector to block the respective said drive circuit of said second driving electrodes .

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