JP2009266921A - Laminated piezoelectric actuator element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated piezoelectric actuator element which excels in response characteristics and which is capable of further suppressing the input current amount than the conventional types, in order to obtain a response speed equal to that of the conventional one, while when an input current amount equivalent to that of the conventional one is applied, the response speed is increased. <P>SOLUTION: The laminated piezoelectric actuator element is configured by a laminate where a plurality of piezoelectric-body layers 2A-2H and a plurality of conductor layers 3A-3I are alternately laminated and which includes a plurality of piezoelectric units A-H, respectively constituted of a piezoelectric-body layer and a pair of conductor layers sandwiching the piezoelectric-body layer therebetween. The plurality of conductor layers 3A-3I are configured, such that electrode parts 5A-5I for external connection are constituted, by exposing the side ends of the conductor layers 3A-3I on the side faces respectively in which one conductor layer and the other conductor layer adjacent to the one conductor layer across the piezoelectric-body layer are arranged opposite to one another. The plurality of conductor layers are provided with external electrodes 6A, 6B, and 6C connected to the electrode parts 5A-5I for external connection. At least a pair of piezoelectric unit groups 8A, 8B are connected in series. Both the ends of the serially-connected piezoelectric units are respectively provided to each of AC power supply part 7B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laminated piezoelectric actuator element, and in particular, positioning in a precision machine tool, a flow control valve, an actuator for opening a fuel injection nozzle of an automobile, an actuator used for a brake device, etc., and ink ejection of an ink jet printer The present invention relates to a laminated piezoelectric actuator element used for various applications such as a nozzle actuator.

  In order to obtain a larger piezoelectric effect, the laminated piezoelectric actuator element is obtained by alternately laminating a plurality of piezoelectric bodies and electrodes. In this multilayer piezoelectric actuator element, a plurality of electrodes in the element or electrodes between units are connected in series, and the response speed of the element is improved by inputting an AC power supply.

  For example, as shown in FIG. 7, a laminated body 114 in which a plurality of internal electrode layers 113 and piezoelectric layers 112 are alternately stacked so that the internal electrode layers 113 protrude toward alternately opposed side surfaces. A multilayer piezoelectric actuator element 111 is known (see Patent Document 1 and Patent Document 2). In this multilayer piezoelectric actuator element 111, the end surface 115 of the internal electrode layer 113 is exposed on each side surface of the multilayer body 114, and the external electrode disposed along the side surface of the multilayer body 114 is exposed on the end surface 115. 116 is connected.

  Further, as shown in FIG. 8, a laminate in which a plurality of piezoelectric layers 122 and internal electrode layers 123 are alternately stacked so that the internal electrode layers 123 protrude toward the alternately opposing side surfaces. A multilayer piezoelectric actuator element 121 is known in which a plurality of units 124 are joined and integrated through a joint 125 (see Patent Document 3, Patent Document 4, and Patent Document 5). In this multilayer piezoelectric actuator element 121, the end face 126 of the internal electrode layer 123 is exposed on each side face of the multilayer unit 124, and the end face 126 is disposed along the side face of the multilayer piezoelectric actuator element 121. The external electrodes 127A and 127B are connected.

Furthermore, as shown in FIG. 9, there is known a laminated piezoelectric actuator element 131 composed of a laminate 134 in which a plurality of piezoelectric layers 132 and internal electrode layers 133 are alternately laminated (Patent Document 6). reference). In this multilayer piezoelectric actuator element 131, both end surfaces of the internal electrode layer 133 are exposed on both side surfaces of the multilayer body 134, and an insulating layer 135 for preventing a short circuit is alternately formed on each end surface of the internal electrode layer 133. An external electrode 137 provided along the side surface of the stacked body 134 is connected to the other exposed end surface 136 of the internal electrode layer 133.
JP 2005-191050 A JP-A-4-309274 JP-A-5-175565 JP 2004-274030 A JP-A-4-274377 Japanese Patent Laid-Open No. 3-203385

  However, in the conventional multilayer piezoelectric actuator element, a plurality of piezoelectric layers and internal electrode layers arranged in order to exert a piezoelectric effect by applying a voltage to each piezoelectric layer are alternately stacked. It has the structure made. In this configuration, a plurality of piezoelectric units including one piezoelectric layer and internal electrode layers sandwiching the piezoelectric layer are connected in parallel to the external electrodes. Here, the piezoelectric unit has a capacitance by a piezoelectric body sandwiched between the internal electrode layers. Therefore, it is considered that the multilayer piezoelectric actuator element is electrically equivalent to one in which a plurality of capacitors are connected in parallel. Therefore, in the multilayer piezoelectric actuator element in which the conventional piezoelectric units are connected in parallel, the electrostatic capacity is added by the number of the piezoelectric units connected in parallel, and has a large electrostatic capacity.

  By the way, in general, in a piezoelectric actuator element, a piezoelectric phenomenon, that is, displacement of the piezoelectric layer occurs after a charge amount corresponding to the capacitance of the element is completely charged and discharged by a voltage applied to the internal electrode layer. Then, a response as a piezoelectric actuator element to voltage application occurs. As shown in FIG. 10A, when the applied voltage is applied from time t1 to time t3, the response of the element causes a response delay with respect to the applied voltage, and the rising period (t1 → t2), The falling period (t3 → t4) is shown. In this case, as shown in FIG. 10B, the element is charged in the period from t1 to t2 (rise period). When the charging is completed, the element is piezoelectrically displaced by the application of the voltage P during the period from t2 to t3 (displacement period), and the element responds to the application of the voltage P. Then, when the application of the voltage P is finished at t3, the discharge is started, and the discharge is performed during the period from t3 to t4 (discharge period, falling period). By repeating this voltage application → charging (rising) → piezoelectric displacement (response) → ending voltage application → discharging (falling), the piezoelectric actuator element operates. Therefore, the larger the capacitance of the element, the longer the charge / discharge time, i.e., the larger the capacitance, the longer the rise time and fall time of the piezoelectric actuator element. The time until displacement and response, and the time from the end of voltage application to the time of discharge and response to the next voltage application become longer. Therefore, the response speed of the piezoelectric actuator element becomes slow. In such a case, in order to increase the response speed, it is necessary to increase the input current amount or decrease the capacitance and the applied voltage.

  On the other hand, in the conventional multilayer piezoelectric actuator element, as described above, the capacitance is added by the number of piezoelectric units connected in parallel, and has a large capacitance. Therefore, the conventional multilayer piezoelectric actuator element has a problem that the response speed is slow due to a large capacitance. In order to increase the displacement of the multilayer piezoelectric actuator element, that is, to increase the displacement of the piezoelectric layer due to the application of voltage to the plurality of piezoelectric units constituting the multilayer piezoelectric actuator element, the number of piezoelectric layers is increased. It is necessary to increase the applied voltage, or to laminate a larger number of piezoelectric layers by thinning the piezoelectric layers. Even in such a case, in the conventional multilayer piezoelectric actuator element, the capacitance increases, the amount of charge necessary to charge the element increases, and the response speed decreases.

  In such a laminated piezoelectric actuator element, as described above, it is necessary to increase the amount of input current in order to increase the response speed. However, in order to increase the amount of input current to the element, the number of parts of the field effect transistor (FET) of the control circuit used for driving the element is increased, the internal electrode and the external electrode that can withstand the excessive current amount are enlarged, A power supply unit such as a voltage or current harness connected to the actuator is required, and a decrease in capacitance and applied voltage leads to a decrease in displacement and force generated by the actuator and an increase in cost.

  Further, the conventional multilayer piezoelectric actuator element is composed of a multilayer body in which piezoelectric layers and internal electrode layers are alternately stacked, and is connected to the end face of the internal electrode layer exposed on the side surface of the multilayer body. Since it is necessary to form the electrode according to the length of the laminate in the stacking direction, a long external electrode must be formed. Further, since the area of the surface on which the external electrode is formed becomes large, there is a problem that the weight and cost of the multilayer piezoelectric actuator element are increased. Further, the dimensional accuracy of the external electrode causes a failure of the electrical contact, and there is a problem that the device cannot be driven and further causes a failure.

  Therefore, an object of the present invention is to improve the response characteristics and to obtain a response speed equivalent to that of the conventional case, the input current amount can be suppressed as compared with the conventional case, while an input current amount equivalent to that of the conventional case is applied. In this case, a multilayer piezoelectric actuator element can be provided that has a faster response speed, and that is lighter and less expensive than conventional ones, and can reduce the size of the external electrode that can be one of the causes of element failure. There is to do.

  In order to solve the above-described problem, a multilayer piezoelectric actuator element according to claim 1 includes a plurality of piezoelectric layers and conductor layers alternately stacked, and a pair of conductors sandwiching the piezoelectric layers and the piezoelectric layers. And a plurality of conductor layers, wherein the plurality of conductor layers are one conductor layer and another conductor layer adjacent to the one conductor layer with the piezoelectric layer interposed therebetween. Each of the side surfaces of the conductor layer is exposed to form an external connection electrode portion, and includes an external electrode connected to the external connection electrode portion, of the plurality of piezoelectric units. At least a pair of piezoelectric units are connected in series, and AC power supply units are provided at both ends of the piezoelectric units connected in series.

  This multilayer piezoelectric actuator element is composed of a multilayer body in which a plurality of piezoelectric layers and conductor layers are alternately stacked, and the plurality of conductor layers includes one conductor layer and one conductor across the piezoelectric layer. The other conductive layer adjacent to the layer comprises the external electrode connected to the external connection electrode part, with the side edges of the conductive layer being exposed on the opposing side surfaces to constitute the external connection electrode part, At least a pair of conductor layers of the plurality of piezoelectric units are connected in series by external electrodes, and an AC power supply unit is provided at both ends of the conductor layers connected in series, so that the response characteristics of the multilayer piezoelectric actuator element are improved. Improves the response speed.

  According to a second aspect of the present invention, in the multilayer piezoelectric actuator element, the external electrode is continuously disposed along the stacking direction on one side surface along the stacking direction of the stacked body, and the other side surface. Further, the two external electrodes are arranged so as to be electrically separated from each other.

  In this multilayer piezoelectric actuator element, external electrodes are continuously arranged along one side surface along the stacking direction of the multilayer body, and two external electrodes are electrically connected to each other on the other side surface. Since the terminals can be integrated on one side of the multilayer piezoelectric actuator element, the system or device using the multilayer piezoelectric actuator element can be miniaturized.

  According to a third aspect of the present invention, a plurality of piezoelectric layers and conductor layers are alternately stacked, and the plurality of conductor layers sandwich one piezoelectric layer and the piezoelectric layers. The one conductor layer and the other conductor layer adjacent to each other are connected to the external connection electrode portion, with the side edges of the conductor layer being exposed at the opposing side surfaces to form an external connection electrode portion. A multilayer piezoelectric actuator element in which a plurality of multilayer piezoelectric actuator element units each having an external electrode are connected, wherein the plurality of multilayer piezoelectric actuator element units are connected in series via an adhesive layer, and at least a pair of multilayer piezoelectric actuators The element unit is electrically connected in series, and AC power supply units are provided at both ends of the stacked piezoelectric actuator element units electrically connected in series.

  This multilayer piezoelectric actuator element is composed of a multilayer body in which a plurality of piezoelectric layers and conductor layers are alternately stacked, and the plurality of conductor layers include the one conductor layer and the piezoelectric layer sandwiched therebetween. An external electrode connected to the external connection electrode portion, wherein one conductive layer and another adjacent conductive layer constitute the external connection electrode portion with the side edges of the conductive layer exposed at the opposing side surfaces. A plurality of stacked piezoelectric actuator element units, wherein a plurality of stacked piezoelectric actuator element units are connected in series via an adhesive layer, and at least a pair of stacked piezoelectric actuator element units are electrically connected in series In addition, by providing AC power supply units at both ends of the stacked piezoelectric actuator element units electrically connected in series, the response characteristics of the stacked piezoelectric actuator element are improved. And, the response speed is fast.

  According to a fourth aspect of the present invention, in the multilayer piezoelectric actuator element, the external electrodes are arranged continuously along the longitudinal direction on one side surface along the longitudinal direction of the multilayer piezoelectric actuator elements connected in series. On the other side surface, the two external electrodes are arranged so as to be electrically separated from each other.

  In this multilayer piezoelectric actuator element, the external electrode is continuously arranged along the longitudinal direction on one side surface along the longitudinal direction of the multilayer piezoelectric actuator elements connected in series, and the other side surface has 2 By arranging the two external electrodes so as to be electrically separated from each other, the terminals can be integrated on one side of the multilayer piezoelectric actuator element, thereby miniaturizing systems and devices using the multilayer piezoelectric actuator element. it can.

  The multilayer piezoelectric actuator element according to the first aspect of the present invention is excellent in response characteristics, and in order to obtain a response speed equivalent to the conventional one, the amount of input current can be suppressed as compared with the conventional one. When an equivalent input current amount is applied, the response speed is increased, and further, the size of the external electrode that causes a failure of the element can be reduced at a lighter and lower cost than the conventional one. Therefore, the response time can be shortened without increasing the input current value. Therefore, the response speed can be increased. Further, since the response is performed with a low input current amount, the influence of the contact resistance (allowable applied current) is small, and the driving failure of the element is reduced. In addition, since there is no need for a large-current FET for the control circuit, the cost can be reduced, and an increase in the number of in-vehicle components can be suppressed in the in-vehicle laminated piezoelectric actuator element. Furthermore, the size of the external electrode can be reduced, and the area of the surface on which the external electrode is formed does not increase, and the weight and cost of the stacked piezoelectric actuator element do not increase. Further, it is possible to reduce the possibility of defective electrical contacts due to the dimensional accuracy of the external electrodes, and to reduce the inability to drive the device and further the failure.

  According to the second aspect of the present invention, since the terminals can be integrated on one side of the multilayer piezoelectric actuator element, the multilayer piezoelectric actuator element can be miniaturized.

  The laminated piezoelectric actuator element of the invention according to claim 3 is excellent in response characteristics, and in order to obtain a response speed equivalent to the conventional one, it is possible to suppress the input current amount as compared with the conventional one. When an equivalent input current amount is applied, the response speed is increased, and further, the size of the external electrode that causes a failure of the element can be reduced at a lighter and lower cost than the conventional one. Therefore, the response time can be shortened without increasing the input current value. Therefore, the response speed can be increased.

  According to the invention described in claim 4, since the terminals can be integrated on one side of the multilayer piezoelectric actuator element, the multilayer piezoelectric actuator element can be miniaturized.

Hereinafter, the multilayer piezoelectric actuator element of the present invention will be described in detail based on embodiments.
FIG. 1A is a schematic diagram showing the structure of the multilayer piezoelectric actuator element 1 according to the first embodiment of the present invention, and FIG. 1B is an electrical equivalent of the multilayer piezoelectric actuator element 1. It is a figure which shows a circuit.

  The laminated piezoelectric actuator element 1 shown in FIG. 1A includes piezoelectric layers 2A, 2B, 2C, 2D, 2E, 2F, 2G, and 2H, and conductor layers 3A, 3B, 3C, 3D, 3E, 3F, and 3G. , 3H, 3I are alternately stacked. The piezoelectric layer 2A is sandwiched between the conductor layers 2A and 2B to constitute the piezoelectric unit A. The piezoelectric layers 2B, 2C, 2D, 2E, 2F, 2G, and 2H are also formed between the conductor layers 3B and 3C, between the conductor layers 3C and 3D, between the conductor layers 3D and 3E, and between the conductor layers 3E and 3F. Between the conductor layers 3F and 3G, between the conductor layers 3G and 3H, and between the conductor layers 3H and 3I, and constitutes the piezoelectric units B, C, D, E, F, G, and H, respectively. .

  Each of the piezoelectric layers 2A, 2B, 2C, 2D, 2E, 2F, 2G, and 2H is formed of, for example, barium titanate, lead zirconate, lead zirconate titanate, or the like.

  Each of the conductor layers 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H, and 3I includes one conductor layer and another conductor layer adjacent to the one conductor layer with the piezoelectric layer 2 interposed therebetween. Each of the opposing side surfaces has external connection electrode portions formed by exposing the side edges of the conductor layer 3. That is, the conductor layers 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H, and 3I are protruded toward the alternately opposed side surfaces of the multilayer body 4, and are disposed on the opposite side surfaces of the multilayer body 4 one by one. The side ends of the conductor layers 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H, 3I are exposed, and the external connection electrodes 5A, 5B, 5C, 5D, 5E, 5F, 5G, 5H, 5I Forming.

  External connection electrode portions 5A, 5B, 5C, 5D, 5E, 5F, 5G, 5H, 5I formed on the side ends of the conductor layers 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H, 3I are Are connected to external electrodes 6A, 6B, 6C formed on the side surfaces of the laminate 4, respectively.

  In this multilayer piezoelectric actuator element 1, in the piezoelectric units A, B, C and D, the conductor layers 3B and 3D are connected to the external electrode 6A by the external connection electrode portions 5B and 5D, and the conductor layers 3A, 3C, 3E is connected to the external electrode 6B by the external connection electrode portions 5A, 5C, and 5E. Accordingly, the piezoelectric units A, B, C, and D are connected in parallel to the external electrode 6A and the external electrode 6B to constitute one piezoelectric unit group 8A.

  In the piezoelectric units E, F, G, and H, the conductor layers 3E, 3G, and 3I are connected to the external electrode 6B by the external connection electrode portions 5E, 5G, and 5I, and the conductor layers 3F and 3H are for external connection. The electrode portions 5F and 5H are connected to the external electrode 6C. Therefore, the piezoelectric units E, F, G, and H are connected in parallel to the external electrode 6B and the external electrode 6C to constitute one piezoelectric unit group 8B.

  In the multilayer piezoelectric actuator element 1, the piezoelectric unit group 8A and the piezoelectric unit group 8B are connected in series by the external electrode 6B. The piezoelectric unit group 8A and the piezoelectric unit group 8B connected in series are connected to the AC power supply unit 7A connected to the external electrode 6A connected to the conductor layers 3B and 3D and the conductor layers 3F and 3H. AC power supply unit 7B (ground) connected to external electrode 6C. An oscillating AC current is supplied between the AC power supply unit 7A and the AC power supply unit 7B (earth) to oscillate each of the piezoelectric units A, B, C, D, E, F, G, and H. Make it respond.

  In this multilayer piezoelectric actuator element 1, a piezoelectric unit group 8A composed of piezoelectric units A, B, C and D (capacitance of each piezoelectric unit is Ca, Cb, Cc, Cd) connected in parallel. Is the sum of the capacitances of the piezoelectric units A, B, C and D. The capacitance of the piezoelectric unit group 8A is C1 (= Ca + Cb + Cc + Cd). On the other hand, the capacitance of the piezoelectric unit group 8B composed of the piezoelectric units E, F, G and H connected in parallel (the capacitance of each piezoelectric unit is Ce, Cf, Cg, Ch) is This is the sum of the capacitances of the units E, F, G and H. The capacitance of the piezoelectric unit group 8B is C2 (= Ce + Cf + Cg + Ch). Therefore, as shown in FIG. 1 (b), the multilayer piezoelectric actuator element 1 includes a piezoelectric unit group 8A having a capacitance C1 and a piezoelectric unit group 8B having a capacitance C2 connected in series. It is. Therefore, the capacitance Ctotal of the multilayer piezoelectric actuator element 1 is Ctotal = (1 / C1) + (1 / C2). On the other hand, the capacitance of the element in which the piezoelectric units A, B, C, D, E, F, G, and H are connected in parallel is (Ca + Cb + Cc + Cd + Ce + Cf + Cg + Ch). Therefore, the electrostatic capacity of the multilayer piezoelectric actuator element 1 is lower than the electrostatic capacity of the element in which the piezoelectric units A, B, C, D, E, F, G, and H are connected in parallel. Become. For this reason, the charge / discharge time of the multilayer piezoelectric actuator element 1 is shorter than that of the element in which the piezoelectric units A, B, C, D, E, F, G, and H are connected in parallel. It can be seen that the response speed of the actuator element 1 is increased. Here, when Ca = Cb = Cc = Cd = Ce = Cf = Cg = Ch, C1 = C2, and eventually the capacitance of the multilayer piezoelectric actuator element 1 is C1 / 2. The discharge time is ½ of the element in which the piezoelectric units A, B, C, D, E, F, G, and H are connected in parallel. Accordingly, the response speed is halved and the response characteristics are improved.

Next, a second embodiment and a third embodiment of the present invention will be described.
FIG. 2A is a schematic diagram showing the structure of a multilayer piezoelectric actuator element 20 according to the second embodiment of the present invention, and FIG. 2B is a multilayer piezoelectric actuator according to the third embodiment of the present invention. FIG. 2C is a schematic diagram showing the structure of the actuator element 30, and FIG. 2C is a diagram showing an electrical equivalent circuit of the stacked piezoelectric actuator elements 20 and 30.

  The laminated piezoelectric actuator element 20 shown in FIG. 2A includes piezoelectric layers 22A, 22B, 22C, 22D, 22E, 22F, 22G, 22H, 22I, and 22J, and conductor layers 23A, 23B, 23C, 23D, and 23E. , 23F, 23G, 23H, 23I, 23J, and 23K. The piezoelectric layer 22A is sandwiched between the conductor layers 22A and 22B to constitute the piezoelectric unit 20A. In addition, the piezoelectric layers 22B, 22C, 22D, 22E, 22F, 22G, 22H, 22I, and 22J are also provided between the conductor layers 23B and 23C, between the conductor layers 23C and 23D, between the conductor layers 23D and 23E, and between the conductor layers. 23E and 23F, between the conductor layers 23F and 23G, between the conductor layers 23G and 23H, between the conductor layers 23H and 23I, between the conductor layers 23I and 23J, between the conductor layers 23J and 23K, The piezoelectric units 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20I, and 20J are configured.

  The conductor layers 23A, 23B, 23C, 23D, 23E, 23F, 23G, 23H, 23I, 23J, and 23K are respectively one conductor layer and another conductor layer adjacent to the one conductor layer with the piezoelectric layer interposed therebetween. Have external connection electrode portions formed by exposing the side edges of the conductor layers on the opposite side surfaces. That is, the conductor layers 23A, 23B, 23C, 23D, 23E, 23F, 23G, 23H, 23I, 23J, and 23K are projected toward the alternately opposed side surfaces of the multilayer body 24, and the opposite side surfaces of the multilayer body 24 are opposed to each other. For each layer, the side edges of the conductor layers 23A, 23B, 23C, 23D, 23E, 23F, 23G, 23H, 23I, 23J, and 23K are exposed, and the external connection electrode portions 25A, 25B, 25C, 25D, 25E, 25F, 25G, 25H, 25I, 25J, and 25K are formed.

  External connection electrode portions 25A, 25B, 25C, 25D, 25E, 25F, 25G formed on the side ends of the conductor layers 23A, 23B, 23C, 23D, 23E, 23F, 23G, 23H, 23I, 23J, 23K, 25H, 25I, 25J, and 25K are connected to external electrodes 26A, 26B, 26C, 26D, and 26E formed on the side surfaces of the laminate 24, respectively.

  In this multilayer piezoelectric actuator element 20, in the piezoelectric units 20A, 20B, and 20C, the conductor layers 23A and 23C are connected to the external electrode 26A by the external connection electrode portions 25A and 25C, and the conductor layers 23B and 23D are externally connected. The connection electrodes 25B and 25D are connected to the external electrode 26B. Therefore, the piezoelectric units 20A, 20B, and 20C are connected in parallel to the external electrode 26A and the external electrode 26B to constitute one piezoelectric unit group 28A.

  In the piezoelectric units 20E, 20F, and 20G, the conductor layers 23E and 23G are connected to the external electrode 26C by the external connection electrode portions 25E and 25G, and the conductor layers 23D and 23F are connected by the external connection electrode portions 25D and 25F. The external electrodes 26B and 26C are connected. Accordingly, the piezoelectric units 20E, 20F, and 20G are connected in parallel to the external electrode 26B and the external electrode 26C to constitute one piezoelectric unit group 28B.

  In the piezoelectric unit 20D, the conductor layer 23D is connected to the external electrode 26B by the external connection electrode portion 25C, and the conductor layer 23E is connected to the external electrode 26C by the external connection electrode portion 25E. Therefore, the piezoelectric unit 20D is connected in series with the piezoelectric unit group 28A and the piezoelectric unit 28B via the conductor layers 23D and 23E, respectively.

  In the piezoelectric units 20H, 20I and 20J, the conductor layers 23H and 23J are connected to the external electrode 26D by the external connection electrode portions 25H and 25J, and the conductor layers 23I and 23K are connected by the external connection electrode portions 25I and 25K. The external electrode 26E is connected. Accordingly, the piezoelectric units 20H, 20I, and 20J are connected in parallel to the external electrode 26D and the external electrode 26E, and constitute one piezoelectric unit group 28C.

  In the multilayer piezoelectric actuator element 20, the piezoelectric unit group 28A, the piezoelectric unit 20D, the piezoelectric unit group 28B, and the piezoelectric unit group 28C are connected in series by external electrodes 26B, 26C, and 26D. . The piezoelectric unit group 28A, the piezoelectric unit 20D, the piezoelectric unit group 28B, and the piezoelectric unit group 28C connected in series are connected to the AC power supply unit 27A and the AC connected to the external electrodes 26A and 26E at both ends, respectively. It has a power supply unit 27B (ground). An oscillating AC current is supplied between the AC power supply unit 27A and the AC power supply unit 27B (earth), so that each of the piezoelectric units 20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20I, and 20J. Oscillates and makes it respond.

  In this multilayer piezoelectric actuator element 20, the capacitance of a piezoelectric unit group 28A composed of piezoelectric units 20A, 20B and 20C connected in parallel (capacitance of each piezoelectric unit is Ca, Cb, Cc). Is the sum of the capacitances of the piezoelectric units 20A, 20B and 20C. The capacitance of the piezoelectric unit group 28A is C1 (= Ca + Cb + Cc). On the other hand, the capacitance of the piezoelectric unit group 28B composed of the piezoelectric units 20E, 20F, and 20G connected in parallel (the capacitance of each piezoelectric unit is Ce, Cf, and Cg) is 20E, 20F, and 20G. It becomes the total of each electrostatic capacitance which has. The capacitance of the piezoelectric unit group 28B is C2 (= Ce + Cf + Cg). Further, the capacitance of the piezoelectric unit group 28C composed of the piezoelectric units 20H, 20I and 20J connected in parallel (the capacitance of each piezoelectric unit is Ch, Ci, Cj) is the piezoelectric unit 20H, 20I. And the total capacitance of 20J. The capacitance of the piezoelectric unit group 28C is C3 (= Ch + Ci + Cj). Further, the capacitance of the piezoelectric unit 20D is Cd.

  Here, as shown in FIG. 2C, the laminated piezoelectric actuator element 20 includes a piezoelectric unit group 28A having a capacitance C1, a piezoelectric unit 20D having a capacitance Cd, and a piezoelectric unit having a capacitance C2. The group 28B and the piezoelectric unit group 28C having the capacitance C3 are connected in series. Therefore, the capacitance Ctotal of the multilayer piezoelectric actuator element 1 is Ctotal = (1 / C1) + (1 / Cd) + (1 / C2) + (1 / C3). On the other hand, the capacitance of the element in which the piezoelectric units 20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20I, and 20J are connected in parallel is C (Ca + Cb + Cc + Cd + Ce + Cf + Cg + Ch + Ci + Cj). Therefore, the electrostatic capacity of the multilayer piezoelectric actuator element 20 is lower than the electrostatic capacity of the element in which the piezoelectric units A, B, C, D, E, F, G, and H are connected in parallel. Become. Therefore, the charge / discharge time of the multilayer piezoelectric actuator element 20 is shorter than that of the element in which the piezoelectric units 20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20I, and 20J are connected in parallel. The response speed of the multilayer piezoelectric actuator element 20 is increased, and the response characteristics are improved.

  Next, FIG.2 (b) is a schematic diagram which shows the structure of the laminated piezoelectric actuator element 30 which concerns on 3rd Embodiment of this invention.

  The laminated piezoelectric actuator element 30 shown in FIG. 2B includes piezoelectric layers 32A, 32B, 32C, 32D, 32E, 32F, 32G, 32H, 32I, 32J, 32K, 32L, 32M, and 32N, and a conductor layer 33A. , 33B, 33C, 33D, 33E, 33F, 33G, 33H, 33I, 33J, 33K, 33L, 33M, 33N, and 33P. The piezoelectric layer 32A is sandwiched between the conductor layers 33A and 33B to constitute a piezoelectric unit 30A. Further, the piezoelectric layers 32B, 32C, 32D, 32E, 32F, 32G, 32H, 32I, 32J, 32K, 32L, 32M, and 32N are also provided between the conductor layers 33B and 33C, between the conductor layers 33C and 33D, and between the conductor layers 33C and 33D. 33D and 33E, between conductor layers 33E and 33F, between conductor layers 33F and 33G, between conductor layers 33G and 33H, between conductor layers 33H and 33I, between conductor layers 33I and 33J, and between conductor layers 33K 33L, between the conductor layers 33L and 33M, and between the conductor layer 33N and the conductor layer 33P, respectively, and the piezoelectric units 30B, 30C, 30D, 30E, 30F, 30G, 30H, 30I, 30J, 30K, 30L, 30M and 30N are configured.

  Conductor layers 33A, 33B, 33C, 33D, 33E, 33F, 33G, 33H, 33I, 33J, 33K, 33L, 33M, 33N, 33P, and piezoelectric layers 32A, 32B, 32C, 32D, 32E, 32F, 32G, 32H, 32I, 32J, 32K, 32L, 32M, and 32N are conductors on the side surfaces where one conductor layer and another conductor layer adjacent to one conductor layer sandwiching the piezoelectric layer are opposed to each other. An external connection electrode portion is formed by exposing the side end of the layer. That is, the conductor layers 3A, 33B, 33C, 33D, 33E, 33F, 33G, 33H, 33I, 33J, 33K, 33L, 33M, 33N, and 33P are projected toward the alternately opposed side surfaces of the multilayer body 34. The side edges of the conductor layers 3A, 33B, 33C, 33D, 33E, 33F, 33G, 33H, 33I, 33J, 33K, 33L, 33M, 33N, and 33P are exposed on the opposite side surfaces of the laminate 34. The external connection electrode portions 35A, 35B, 35C, 35D, 35E, 35F, 35G, 35H, 35I, 35J, 35K, 35L, 35M, 35N, and 35P are formed.

External connection electrode portions 35A, 35B, 35C formed on the side ends of the conductor layers 33A, 33B, 33C, 33D, 33E, 33F, 33G, 33H, 33I, 33J, 33K, 33L, 33M, 33N, 33P, 35D, 35E, 35F, 35G, 35H, 35I, 35J, 35K, 35L, 35M, 35N, and 35P are external electrodes 36A, 36B, 36C, 36D, 36E, 36F, and 36G formed on the side surfaces of the laminate 34, respectively. Connected to.

  In the multilayer piezoelectric actuator element 30, in the piezoelectric unit 30A, the conductor layer 33A is connected to the external electrode 36A by the external connection electrode portion 35A, and the conductor layer 33B is connected to the external electrode 36B by the external connection electrode portion 35B. It is connected. The same applies to the piezoelectric units 30B, 30C, 30D, 30E, 30F, 35G, 35H, 35I, 35J, 35K, 35L, 35M, 35N, and 35P.

  In this multilayer piezoelectric actuator element 30, in the piezoelectric units 30A, 30B and 30C, the conductor layers 33A and 33C are connected to the external electrode 36A by the external connection electrode portions 35A and 35C, and the conductor layers 33B and 33D are connected. The external connection electrode portions 35B and 35D are connected to the external electrode 36B. Accordingly, the piezoelectric units 30A, 30B, and 30C are connected in parallel to the external electrode 36A and the external electrode 36B to constitute one piezoelectric unit group 38A.

  In the piezoelectric unit 30D, the conductor layer 33D is connected to the external electrode 36B by the external connection electrode portion 35D, and the conductor layer 33E is connected to the external electrode 36C by the external connection electrode portion 35E. In the piezoelectric unit 30D, a piezoelectric unit group 38A and a piezoelectric unit group 38B described later are connected in series.

  In the piezoelectric units 30E, 30F, and 30G, the conductor layers 33E and 33G are connected to the external electrode 36C by the external connection electrode portions 35E and 35G, and the conductor layers 33F and 33H are connected by the external connection electrode portions 35F and 35H. Are connected to the external electrode 36D. Accordingly, the piezoelectric units 30E, 30F, and 30G are connected in parallel to the external electrode 36C and the external electrode 36D, and constitute one piezoelectric unit group 38B.

  In the piezoelectric unit 30H, the conductor layer 33H is connected to the external electrode 36D by the external connection electrode portion 35H, and the conductor layer 33I is connected to the external electrode 36E by the external connection electrode portion 35I. The piezoelectric unit 30H connects a piezoelectric unit group 38B and a piezoelectric unit group 38C described later in series.

  In the piezoelectric units 30I, 30J and 30K, the conductor layers 33I and 33K are connected to the external electrode 36E by the external connection electrode portions 35I and 35K, and the conductor layers 33J and 23L are connected by the external connection electrode portions 35J and 35L. The external electrode 36F is connected. Accordingly, the piezoelectric units 30I, 30J, and 30K are connected in parallel to the external electrode 36E and the external electrode 36F, and constitute one piezoelectric unit group 38C.

  Furthermore, in the piezoelectric units 30L, 30M, and 30N, the conductor layers 33L and 33N are connected to the external electrode 36F by the external connection electrode portions 35L and 35N, and the conductor layers 33M and 33P are connected by the external connection electrode portions 35M and 35P. The external electrode 36G is connected. Therefore, the piezoelectric units 30L, 30M, and 30N are connected in parallel to the external electrode 36F and the external electrode 36G to constitute one piezoelectric unit group 38D.

  In this stacked piezoelectric actuator element 30, the piezoelectric unit group 38A, the piezoelectric unit 30D, the piezoelectric unit group 38B, the piezoelectric unit 30H, the piezoelectric unit group 28C, and the piezoelectric unit group 38D are external electrodes 36B, 36C, 36D, 36E, 6F, and 36G are connected in series. In addition, the piezoelectric unit group 38A, the piezoelectric unit 30D, the piezoelectric unit group 38B, the piezoelectric unit 30H, the piezoelectric unit group 28C, and the piezoelectric unit group 38D connected in series are connected to the external electrodes 36A and 36G at both ends. Each has an AC power supply unit 37A and an AC power supply unit 37B (ground) connected to each other. An oscillating AC current is supplied between the AC power supply unit 37A and the AC power supply unit 37B (earth), so that each of the piezoelectric units 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, 30I, and 30J. , 30K, 30L, 30M, 30N are oscillated and made to respond.

  In this laminated piezoelectric actuator element 30, the capacitance of a piezoelectric unit group 38A composed of piezoelectric units 30A, 30B and 30C connected in parallel (capacitance of each piezoelectric unit is Ca, Cb, Cc). Is the sum of the capacitances of the piezoelectric units 30A, 30B and 30C. The capacitance of the piezoelectric unit group 38A is C1 (= Ca + Cb + Cc). On the other hand, the capacitance of the piezoelectric unit group 38B composed of the piezoelectric units 30E, 30F, and 30G connected in parallel (the capacitance of each piezoelectric unit is Ce, Cf, Cg) is the piezoelectric unit 30E, 30F. And the total capacitance of 30G. The capacitance of the piezoelectric unit group 38B is C2 (= Ce + Cf + Cg). Further, the capacitance of the piezoelectric unit group 38C composed of the piezoelectric units 30I, 30J and 30K connected in parallel (the capacitance of each piezoelectric unit is Ci, Cj, Ck) is the piezoelectric unit 30I, 30J. And the total capacitance of 30K. The capacitance of the piezoelectric unit group 38C is C3 (= Ci + Cj + Ck). Further, the capacitances of the piezoelectric units 30D and 30H are Cd and Ch. In addition, the capacitance of the piezoelectric unit group 38D composed of the piezoelectric units 30L, 30M, and 30N connected in parallel (the capacitance of each piezoelectric unit is Cl, Cm, Cn) is the piezoelectric unit 30L, 39M. And the total capacitance of 30N. The capacitance of the piezoelectric unit group 38D is C4 (= Cl + Cm + Cn).

  In this multilayer piezoelectric actuator element 30, a multilayer piezoelectric actuator element comprising a piezoelectric unit group 38A, a piezoelectric unit 30D, a piezoelectric unit group 38B, a piezoelectric unit 30H, a piezoelectric unit group 28C, and a piezoelectric unit group 38D connected in series. The capacitance of 30 is (1 / C1) + (1 / Cd) + (1 / C2) + (1 / Ch) + (1 / C3) + (1 / C4).

  On the other hand, the capacitance of the element in which the piezoelectric unit units 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, 30I, 30J, 30K, 30L, 30M, and 30N are connected in parallel is ( Ca + Cb + Cc + Cd + Ce + Cf + Cg + Ch + Ci + Cj + Ck + Cm + Cn). Accordingly, the capacitance of the multilayer piezoelectric actuator element 30 is such that the piezoelectric unit units 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, 30I, 30J, 30K, 30L, 30M, and 30N are connected in parallel. It becomes a low value compared with the electrostatic capacitance of the element of a structure. Therefore, the charge / discharge time of the multilayer piezoelectric actuator element 30 is such that the piezoelectric unit units 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, 30I, 30J, 30K, 30L, 30M, and 30N are connected in parallel. Thus, the response speed of the multilayer piezoelectric actuator element 30 is increased and the response characteristics are improved.

  Next, FIG. 3 is a schematic diagram showing a structure of a multilayer piezoelectric actuator element 40 according to the fourth embodiment of the present invention, and FIG. 2B is an electrical equivalent of the multilayer piezoelectric actuator element 40. It is a figure which shows a circuit.

  The laminated piezoelectric actuator element 40 shown in FIG. 3A includes piezoelectric layers 42A, 42B, 42C, 42D, 42E, 42F, 42G, 42H, 42I, and 42J, and conductor layers 43A, 43B, 43C, 43D, and 43E. , 43F, 43G, 43H, 43I, and 43J. The piezoelectric layer 42A is sandwiched between the conductor layers 43A and 43B to constitute the piezoelectric unit 40A. Further, the piezoelectric layers 42B, 42C, 42D, 42E, 42F, 42G, 42H, 42I, and 42J are also provided between the conductor layers 43B and 43C, between the conductor layers 43C and 43D, between the conductor layers 43D and 43E, and between the conductor layers. It is sandwiched between 43F and 43G, between conductor layers 43G and 43H, between conductor layers 43H and 43I, and between conductor layers 43I and 43J, and constitutes piezoelectric units 40B, 40C, 40D, 40F, 40G, and 40H, respectively. is doing. The piezoelectric unit 40D and the piezoelectric unit 40F are separated by a bonding layer 49. The bonding layer 49 is formed of an insulating adhesive material typified by epoxy or silicon.

  Each of the conductor layers 43A, 43B, 43C, 43D, 43E, 43F, 43G, 43H, 43I, and 43J includes one conductor layer and another conductor layer adjacent to the one conductor layer with the piezoelectric layer interposed therebetween. The external connection electrode portions are formed on the side surfaces facing each other, with the side edges of the conductor layers exposed. That is, the conductor layers 43A, 43B, 43C, 43D, 43E, 43F, 43G, 43H, 43I, and 43J are protruded toward the alternately opposing side surfaces of the multilayer body 44, and are further formed on the opposing side surfaces of the multilayer body 44. In each case, the side ends of the conductor layers 43A, 43B, 43C, 43D, 43E, 43F, 43G, 43H, 43I, 43J are exposed, and the external connection electrode portions 45A, 45B, 45C, 45D, 45E, 45F, 45G, 45H, 45I, and 45J are formed.

  External connection electrode portions 45A, 45B, 45C, 45D, 45E, 45F, 45G, 45H, formed on the side ends of the conductor layers 43A, 43B, 43C, 43D, 43E, 43F, 43G, 43H, 43I, 43J, 45I and 45J are connected to external electrodes 46A, 46B and 46C formed on the side surfaces of the laminate 44, respectively.

  In this multilayer piezoelectric actuator element 40, in the piezoelectric units 40A, 40B, 40C, and 40D, the conductor layers 43A, 43C, and 43E are connected to the external electrode 46A by the external connection electrode portions 45A, 45C, and 45E. 43B and 43D are connected to the external electrode 46B by external connection electrode portions 45B and 45D. Accordingly, the piezoelectric units 40A, 40B, 40C, and 40D are connected in parallel to the external electrode 46A and the external electrode 46B to constitute one piezoelectric unit group 48A.

  In the piezoelectric units 40F, 40G, 49H, and 40I, the conductor layers 43F, 43H, and 43J are connected to the external electrode 46C by the external connection electrode portions 45F, 45H, and 45J, and the conductor layers 43G and 43I are for external connection. The electrode portions 45G and 45I are connected to the external electrode 46B. Therefore, the piezoelectric units 40F, 40G, 49H, and 40I are connected in parallel to the external electrode 46B and the external electrode 46C to constitute one piezoelectric unit group 48B.

  In the multilayer piezoelectric actuator element 40, the piezoelectric unit group 48A and the piezoelectric unit group 48B are connected in series by external electrodes 46A, 46B, and 46C. The piezoelectric unit group 48A and the piezoelectric unit group 48B connected in series include an AC power supply unit 47A connected to the external electrode 46A and an AC power supply unit 47B (ground) connected to the external electrode 46E. Have. An oscillating AC current is supplied between the AC power supply unit 47A and the AC power supply unit 47B (earth) to oscillate and respond to the piezoelectric units 40A, 40B, 40C, 40D, 40F, 40G, and 40H. .

  In this multilayer piezoelectric actuator element 40, a piezoelectric unit group 48A composed of piezoelectric units 40A, 40B, 40C and 40D connected in parallel (capacitance of each piezoelectric unit is Ca, Cb, Cc, Cd). Is the total of the capacitances of the piezoelectric units 40A, 40B, 40C and 40D. The capacitance of the piezoelectric unit group 48A is C1 (= Ca + Cb + Cc + Cd). On the other hand, the capacitance of the piezoelectric unit group 48B composed of the piezoelectric units 40F, 40G, 49H, and 40I connected in parallel (the capacitance of each piezoelectric unit is Cf, Cg, Ch, Ci) is This is the sum of the capacitances of the units 40F, 40G, 49H and 40I. The capacitance of the piezoelectric unit group 48B is C2 (= Cf + Cg + Ch + Ci).

  Here, as shown in FIG. 3B, in this multilayer piezoelectric actuator element 40, a piezoelectric unit group 48A having a capacitance C1 and a piezoelectric unit group 48B having a capacitance C2 are connected in series. Is. Therefore, the capacitance Ctotal of the multilayer piezoelectric actuator element 40 is Ctotal = (1 / C1) + (1 / C2). On the other hand, the capacitance of the element in which the piezoelectric units 40A, 40B, 40C, 40D, 40F, 40G, and 40H are connected in parallel is (Ca + Cb + Cc + Cd + Cf + Cg + Ch + Ci). Therefore, the capacitance of the multilayer piezoelectric actuator element 40 is lower than the capacitance of the element in which the piezoelectric units 40A, 40B, 40C, 40D, 40F, 40G, and 40H are connected in parallel. Therefore, the charge / discharge time of the multilayer piezoelectric actuator element 40 is shorter than that of the element in which the piezoelectric units 40A, 40B, 40C, 40D, 40F, 40G, and 40H are connected in parallel. It can be seen that the response speed of 40 is faster. Here, when Ca = Cb = Cc = Cd = Cf = Cg = Ch = Ci, C1 = C2, and the electrostatic capacity of the multilayer piezoelectric actuator element 40 is eventually C1 / 2. The discharge time is ½ of the element in which the piezoelectric units 40A, 40B, 40C, 40D, 40F, 40G, and 40H are connected in parallel. Accordingly, the response speed is halved and the response characteristics are improved.

  Next, FIGS. 4A and 4B are schematic views showing the structures of the multilayer piezoelectric actuator elements 50 and 60 according to the fifth and sixth embodiments of the present invention. 4 (c) is a diagram showing an electrical equivalent circuit of the laminated piezoelectric actuator elements 50 and 60. FIG.

  The laminated piezoelectric actuator element 50 shown in FIG. 4A includes piezoelectric layers 52A, 52B, 52C, 52D, 52E, 52F, 52G, 52H, and 52I, and conductor layers 53A, 53B, 53C, 53D, 53E, and 53F. , 53G, 53H, 53I, 53J, 53K, and 53L. The piezoelectric layer 52A is sandwiched between the conductor layers 53A and 53B to constitute a piezoelectric unit 50A. In addition, the piezoelectric layers 52B, 52C, 52D, 52E, 52F, 52G, 52H, and 52I are also provided between the conductor layers 53B and 53C, between the conductor layers 53C and 53D, between the conductor layers 53F and 53G, and between the conductor layers 53G and 53G. The piezoelectric units 50B, 50C, 50D, 50F, 50G, 50H, and 50I are formed by being sandwiched between the conductor layers 53I and 53J and between the conductor layers 53J and 53L, respectively. The piezoelectric units 50D and 50E and the piezoelectric units 50F and 50G are separated by bonding layers 59A and 59B. The bonding layers 59A and 59B are formed of an insulating adhesive material typified by epoxy or silicon.

  Conductor layers 53A, 53B, 53C, 53D, 53E, 53F, 53G, 53H, 53I, 53J, 53K, and 53L are respectively adjacent to one conductor layer and one conductor layer with the piezoelectric layer interposed therebetween. The conductor layer has external connection electrode portions formed on the side surfaces facing each other, with the side edges of the conductor layer exposed. That is, the conductor layers 53A, 53B, 53C, 53D, 53E, 53F, 53G, 53H, 53I, 53J, 53K, and 53L are protruded toward the alternately opposed side surfaces of the multilayer body 54, and are opposed to the multilayer body 54. The side ends of the conductor layers 53A, 53B, 53C, 53D, 53E, 53F, 53G, 53H, 53I, 53J, 53K, 53L are exposed on each side surface to be exposed, and external connection electrode portions 55A, 55B, 55C, 55D, 55E, 55F, 55G, 55H, 55I, 55J, 55K, and 55L are formed.

  External connection electrode portions 55A, 55B, 55C, 55D, 55E, 55F formed on the side ends of the conductor layers 53A, 53B, 53C, 53D, 53E, 53F, 53G, 53H, 53I, 53J, 53K, 53L, 55G, 55H, 55I, 55J, 55K, and 55L are connected to external electrodes 56A, 56B, 56C, and 56D formed on the side surfaces of the laminate 54, respectively.

  In this multilayer piezoelectric actuator element 50, in the piezoelectric units 50A, 50B, 50C, the conductor layers 53A, 53C are connected to the external electrode 46B by the external connection electrode portions 55A, 55C, and the conductor layers 53B, 53D are externally connected. The connection electrode portions 55B and 55D are connected to the external electrode 46A. Accordingly, the piezoelectric units 50A, 50B, and 50C are connected in parallel to the external electrode 56A and the external electrode 56B to constitute one piezoelectric unit group 58A.

  In the piezoelectric units 50D, 50E, and 50F, the conductor layers 53E and 53G are connected to the external electrode 56B by the external connection electrode portions 55E and 55G, and the conductor layers 53F and 53H are connected by the external connection electrode portions 55F and 55H. The external electrode 56C is connected. Therefore, the piezoelectric units 50D, 50E, and 50F are connected in parallel to the external electrode 56B and the external electrode 56C to constitute one piezoelectric unit group 58B.

  Further, in the piezoelectric units 50G, 50H and 50I, the conductor layers 53I and 53K are connected to the external electrode 56D by the external connection electrode portions 55I and 55K, and the conductor layers 53J and 53L are connected to the external connection electrode portions 55J and 55L. Is connected to the external electrode 56C. Accordingly, the piezoelectric units 50G, 50H, and 50I are connected in parallel to the external electrode 56Cto the external electrode 56D to constitute one piezoelectric unit group 58C.

  In the multilayer piezoelectric actuator element 50, the piezoelectric unit group 58A, the piezoelectric unit group 58B, and the piezoelectric unit group 58C are connected in series by external electrodes 56A, 56B, 56C, and D. The piezoelectric unit group 58A and the piezoelectric unit group 58C connected in series include an AC power supply unit 57A connected to the external electrode 46A and an AC power supply unit 57B (ground) connected to the external electrode 56D. Have. An oscillating AC current is supplied between the AC power supply unit 57A and the AC power supply unit 57B (earth) to oscillate the piezoelectric units 50A, 50B, 50C, 50D, 50F, 50G, 50H, and 50I. Make it respond.

  In this multilayer piezoelectric actuator element 50, the capacitance of a piezoelectric unit group 58A composed of piezoelectric units 50A, 50B, 50C connected in parallel (capacitance of each piezoelectric unit is Ca, Cb, Cc). Is the sum of the capacitances of the piezoelectric units 50A, 50B and 50C. The capacitance of the piezoelectric unit group 58A is C1 (= Ca + Cb + Cc). In addition, the capacitance of the piezoelectric unit group 58B composed of the piezoelectric units 50D, 50E and 50F connected in parallel (the capacitance of each piezoelectric unit is Cd, Ce, Cf) is the piezoelectric unit 50D, 50E. And the total capacitance of 50F. The capacitance of the piezoelectric unit group 58B is C2 (= Cd + Ce + Cf). Further, the capacitance of the piezoelectric unit group 58C composed of the piezoelectric units 50G, 50H and 50I connected in parallel (the capacitance of each piezoelectric unit is Cg, Ch, Ci) is the piezoelectric unit 50G, 50H. And the total capacitance of 50I. The capacitance of the piezoelectric unit group 58C is C3 (= Cg + Ch + Ci).

  Here, as shown in FIG. 4C, the multilayer piezoelectric actuator element 50 includes a piezoelectric unit group 58A having a capacitance C1, a piezoelectric unit group 58B having a capacitance C2, and a piezoelectric having a capacitance C3. The unit group 58C is connected in series. Therefore, the capacitance Ctotal of the multilayer piezoelectric actuator element 50 is Ctotal = (1 / C1) + (1 / C2) + (1 / C3). On the other hand, the capacitance of the element in which the piezoelectric units 50A, 50B, 50C, 50D, 50F, 50G, 50H, and 50I are connected in parallel is (Ca + Cb + Cc + Cd + Cf + Cg + Ch + Ci). Therefore, the capacitance of the multilayer piezoelectric actuator element 50 is lower than the capacitance of the element in which the piezoelectric units 50A, 50B, 50C, 50D, 50F, 50G, 50H, and 50I are connected in parallel. Become. Therefore, the charge / discharge time of the multilayer piezoelectric actuator element 50 is shorter than that of the element in which the piezoelectric units 50A, 50B, 50C, 50D, 50F, 50G, 50H, and 50I are connected in parallel. It can be seen that the response speed of the actuator element 50 is increased. Here, when Ca = Cb = Cc = Cd = Cf = Cg = Ch = Ci, C1 = C2 = C3. In this case, the capacitance of the multilayer piezoelectric actuator element 50 is C1 / 3, The discharge time is 1/3 of the element in which the piezoelectric units 50A, 50B, 50C, 50D, 50F, 50G, 50H, and 50I are connected in parallel. Therefore, the response speed becomes 1/3 and the response characteristics are improved.

  Next, the multilayer piezoelectric actuator element 60 according to the sixth embodiment of the present invention shown in FIG. 4B includes piezoelectric layers 62A, 62B, 62C, 62E, 62F, 62G, 62I, 62J, 62K, 62M, 62N, 62P, and a laminated body 64 in which conductor layers 63A, 63B, 63C, 63D, 63E, 63F, 63G, 63H, 63I, 63J, 63K, 63L, 63M, 63N, 63P, 63Q are alternately laminated. Has been. The piezoelectric layer 62A is sandwiched between the conductor layers 63A and 63B to constitute the piezoelectric unit 60A. The piezoelectric layers 62B, 62C, 62E, 62F, 62G, 62I, 62J, 62K, 62M, 62N, and 62P are also formed between the conductor layers 63B and 63C, between the conductor layers 63C and 63D, and between the conductor layers 63E and 63F. Between the conductor layers 63F and 63G, between the conductor layers 63G and 63H, between the conductor layers 63I and 63J, between the conductor layers 63J and 63K and between the conductor layers 63K and 63L, between the conductor layers 63M and 63N, Between the conductor layers 63N and 63P, between the conductor layers 63P and 63P, and between the conductor layers 63P and 63Q, the piezoelectric units 60B, 60C, 60D, 60F, 60G, 60H, 60I, 60J, 60K, and 60L are respectively connected. It is composed. The piezoelectric units 60C and 60D, the piezoelectric units 60F and 60G, and the piezoelectric units 60I and 60J are separated by bonding layers 69A, 69B, and 69C. The bonding layers 69A, 69B, and 69C are formed of an insulating adhesive represented by epoxy or silicon.

  The conductor layers 63A, 63B, 63C, 63D, 63E, 63F, 63G, 63H, 63I, 63J, 63K, 63L, 63M, 63N, 63P, and 63Q each have one conductor layer and a piezoelectric layer interposed therebetween. The conductor layer and another conductor layer adjacent to each other have an external connection electrode portion formed by exposing the side end of the conductor layer on the opposite side surfaces. That is, the conductor layers 63A, 63B, 63C, 63D, 63E, 63F, 63G, 63H, 63I, 63J, 63K, 63L, 63M, 63N, 63P, and 63Q protrude toward the alternately opposed side surfaces of the multilayer body 64. Conductor layers 63A, 63B, 63C, 63D, 63E, 63F, 63G, 63H, 63I, 63J, 63K, 63L, 63M, 63N, 63P, and 63Q are provided on the opposite side surfaces of the laminate 64. The ends are exposed to form external connection electrode portions 65A, 65B, 65C, 65D, 65E, 65F, 65G, 65H, 65I, 65J, 65K, 65L, 65M, 65N, 65P, and 65Q.

  External connection electrode portions 65A, 65B formed on the side ends of the conductor layers 63A, 63B, 63C, 63D, 63E, 63F, 63G, 63H, 63I, 63J, 63K, 63L, 63M, 63N, 63P, 63Q, 65C, 65D, 65E, 65F, 65G, 65H, 65I, 65J, 65K, 65L, 65M, 65N, 65P, and 65Q are external electrodes 66A, 66B, 66C, 66D, and 66E formed on the side surfaces of the laminate 64, respectively. Connected to.

  In this multilayer piezoelectric actuator element 60, in the piezoelectric units 60A, 60B and 60C, the conductor layers 63A and 63C are connected to the external electrode 66B by the external connection electrode portions 65A and 65C, and the conductor layers 63B and 63D are externally connected. The connection electrodes 65B and 65D are connected to the external electrode 66A. Accordingly, the piezoelectric units 60A, 60B, and 60C are connected in parallel to the external electrode 66A and the external electrode 66B to constitute one piezoelectric unit group 68A.

  In the piezoelectric units 60D, 60E, and 60F, the conductor layers 63E and 63G are connected to the external electrode 66B by the external connection electrode portions 65E and 65G, and the conductor layers 63F and 63H are connected by the external connection electrode portions 65F and 65H. The external electrode 66C is connected. Therefore, the piezoelectric units 60D, 60E, and 60F are connected in parallel to the external electrode 66B and the external electrode 66C, and constitute one piezoelectric unit group 68B.

  Further, in the piezoelectric units 60G, 60H and 60I, the conductor layers 63I and 63K are connected to the external electrode 66D by the external connection electrode portions 65I and 65K, and the conductor layers 63J and 63L are connected to the external connection electrode portions 65J and 65L. Is connected to the external electrode 66C. Therefore, the piezoelectric units 60G, 60H, and 60I are connected in parallel to the external electrode 66C and the external electrode 66D, and constitute one piezoelectric unit group 68C.

  In the piezoelectric units 60J, 60K, and 60L, the conductor layers 63M and 63P are connected to the external electrode 66D by the external connection electrode portions 65M and 65P, and the conductor layers 63N and 63Q are connected to the external connection electrode portions 65N and 63Q. Is connected to the external electrode 66E. Therefore, the piezoelectric units 60J, 60K, and 60L are connected in parallel to the external electrode 66D and the external electrode 66E, and constitute one piezoelectric unit group 68D.

  In the multilayer piezoelectric actuator element 60, the piezoelectric unit group 68A, the piezoelectric unit group 68B, the piezoelectric unit group 68C, and the piezoelectric unit group 68D are connected in series by external electrodes 66A, 66B, 66C, 66D, and 66E. It is connected to the. In addition, the piezoelectric unit group 68A, the piezoelectric unit group 68B, the piezoelectric unit group 68C, and the piezoelectric unit group 68D include an AC power supply unit 67A connected to the external electrode 66A and an AC power supply connected to the external electrode 66E. It has supply part 67B (earth). An oscillating AC current is supplied between the AC power supply unit 67A and the AC power supply unit 67B (ground) to oscillate and respond to the piezoelectric units 60A, 60B, 60C, 60D, 60F, 60G, and 60H. .

  In this multilayer piezoelectric actuator element 60, the capacitance of a piezoelectric unit group 68A composed of piezoelectric units 60A, 60B and 60C connected in parallel (capacitance of each piezoelectric unit is Ca, Cb, Cc). Is the sum of the capacitances of the piezoelectric units 60A, 60B and 60C. The capacitance of the piezoelectric unit group 68A is C1 (= Ca + Cb + Cc). In addition, the capacitance of the piezoelectric unit group 68B composed of the piezoelectric units 60D, 60E, and 60F connected in parallel (capacitance of each piezoelectric unit is Cd, Ce, Cf) is the piezoelectric unit 60D, 60E. And the total capacitance of 60F. The capacitance of the piezoelectric unit group 68B is C2 (= Cd + Ce + Cf). In addition, the capacitance of the piezoelectric unit group 68C composed of the piezoelectric units 60G, 60H, and 60I connected in parallel (the capacitance of each piezoelectric unit is Cg, Ch, Ci) is as follows. And the total capacitance of 60I. The capacitance of the piezoelectric unit group 68C is C3 (= Cg + Ch + Ci). Further, similarly, the capacitance of the piezoelectric unit group 68D composed of the piezoelectric units 60J, 60K, and 60L is C4 = Cj + Ck + Cl.

  Here, as shown in FIG. 4C, the multilayer piezoelectric actuator element 60 includes a piezoelectric unit group 68A having a capacitance C1, a piezoelectric unit group 68B having a capacitance C2, and a piezoelectric having a capacitance C3. A unit group 68C and a piezoelectric unit group 68D having a capacitance C4 are connected in series. Therefore, the capacitance Ctotal of the multilayer piezoelectric actuator element 60 is Ctotal = (1 / C1) + (1 / C2) + (1 / C3) + (1 / C4). On the other hand, the capacitance of the element in which the piezoelectric units 60A, 60B, 60C, 60D, 60F, 60G, 60H, 60I, 60J, 60K, and 60L are connected in parallel is (Ca + Cb + Cc + Cd + Cf + Cg + Ch + Ci + Cj + Ck + Cl). Therefore, the electrostatic capacity of the multilayer piezoelectric actuator element 60 is the electrostatic capacity of the element in which the piezoelectric units 60A, 60B, 60C, 60D, 60F, 60G, 60H, 60I, 60J, 60K, and 60L are connected in parallel. It becomes a low value compared with. Therefore, the charge / discharge time of the multilayer piezoelectric actuator element 60 is shorter than that of the element in which the piezoelectric units 60A, 60B, 60C, 60D, 60F, 60G, 60H, 60I, 60J, 60K, and 60L are connected in parallel. This shows that the response speed of the multilayer piezoelectric actuator element 60 is increased. Here, when Ca = Cb = Cc = Cd = Cf = Cg = Ch, C1 = C2 = C3 = C4. In this case, the capacitance of the multilayer piezoelectric actuator element 60 is C1 / 4, The discharge time is ¼ of the element in which the piezoelectric units 60A, 60B, 60C, 60D, 60F, 60G, and 60H are connected in parallel. Therefore, the response speed becomes ¼ and the response characteristics are improved.

  As described above, the multilayer piezoelectric actuator element of the present invention has excellent response characteristics, and in order to obtain a response speed equivalent to the conventional one, the amount of input current can be suppressed as compared with the conventional one. When the input current amount is applied, the response speed is increased, and further, the size of the external electrode that causes a failure of the element can be reduced at a lighter and lower cost than the conventional one. Therefore, the response time can be shortened without increasing the input current value. Therefore, the response speed can be increased. Further, since the response is performed with a low input current amount, the influence of the contact resistance (allowable applied current) is small, and the driving failure of the element is reduced. Furthermore, there is no need for a large current compatible FET in the control circuit. Therefore, the cost can be reduced, and the increase in the number of in-vehicle components can be suppressed in the in-vehicle multilayer piezoelectric actuator element. Furthermore, the size of the external electrode can be reduced, and the area of the surface on which the external electrode is formed does not increase, and the weight and cost of the stacked piezoelectric actuator element do not increase. Further, it is possible to reduce the possibility of defective electrical contacts due to the dimensional accuracy of the external electrodes, and to reduce the inability to drive the device and further the failure.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on the Example and comparative example of this invention, this invention is not limited to a following example.

(Example 1, Comparative Example 1)
As Example 1, the piezoelectric characteristics were evaluated using a multilayer piezoelectric actuator element having the configuration shown in Table 1. As shown in FIG. 5, the multilayer piezoelectric actuator element includes 180 layers of a piezoelectric layer 72 made of PZT and a conductor layer 73 sandwiching the piezoelectric layer 72 made of an Ag—Pd alloy, and external electrodes 76A, 76A, 76B and 76C are provided, and two piezoelectric unit groups are formed between the external electrodes 76A and 76B and between the external electrodes 76B and 76C. The dimensions of this multilayer piezoelectric actuator element are shown in FIG.

  On the other hand, as Comparative Example 1, 180 layers of the piezoelectric layer 72 made of PZT and the conductor layer 73 sandwiching the piezoelectric layer 72 made of the Ag—Pd alloy were laminated, and each conductor layer was formed on the side surface of the element. The piezoelectric characteristics of the multilayer piezoelectric actuator element having a configuration in which a plurality of piezoelectric units are connected in parallel by two external electrodes provided on the substrate were evaluated. The driving conditions for the laminated piezoelectric actuator element were based on the model shown in FIGS. 10A and 10B, the waveform was a square wave, the frequency was 1 Hz, and the duty ratio was 0.2%. The duty ratio represents duty ratio (%) = drive time at actual displacement / 1 cycle time × 100 (%).

  At this time, the laminated piezoelectric actuator element was driven with the applied voltage and applied current shown in Table 1, and the capacitance (μF), the amount of piezoelectric displacement (μm), and the response rise time (μsec) were measured. The results are shown in Table 1. Response rise time (μsec) is measured by measuring the time until the applied voltage becomes 250V, 125V, or 0V when the applied voltage is changed from 0V to 250V or 125V, or from 250V or 125V to 0V. can get.

Next, with respect to the laminated piezoelectric actuator elements of Example 1 and Comparative Example 1, the applied voltage and applied current shown in Table 2 and Table 3 were applied, and the effective current and rise time of the laminated piezoelectric actuator element were measured. The results are shown in Table 2 and Table 3.
Shown in

  From the results shown in Table 2 and Table 3, the laminated piezoelectric actuator element (Example 1) of the present invention is shorter than the piezoelectric actuator element of Comparative Example 1 in both the rise time and fall time. It can be seen that the multilayer piezoelectric actuator element of the present invention has excellent response characteristics and a high response speed.

(Example 2, comparative example 2)
As Example 2, the piezoelectric characteristics were evaluated using a laminated piezoelectric actuator element having the configuration shown in Table 1. As shown in FIG. 6, this multilayer piezoelectric actuator element includes a piezoelectric unit group 88A in which 180 layers of a piezoelectric layer 82 made of PZT and a conductor layer 83 sandwiching a piezoelectric layer 82 made of an Ag—Pd alloy are stacked. The piezoelectric unit group 88B is joined via the joint portion 89, and external electrodes 86A, 86B, 86C are provided, and the two piezoelectric unit groups 88A are provided between the external electrodes 86A and 86B and between the external electrodes 86B and 86C. , 88B. The configuration and dimensions of this multilayer piezoelectric actuator element are shown in FIG.

  On the other hand, as Comparative Example 2, 360 layers of a piezoelectric layer 72 made of PZT and a conductor layer 73 sandwiching the piezoelectric layer 72 made of an Ag—Pd alloy were laminated, and each conductor layer was formed on the side surface of the element. The piezoelectric characteristics of the multilayer piezoelectric actuator element having a configuration in which a plurality of piezoelectric units are connected in parallel by two external electrodes provided on the substrate were evaluated. The driving conditions of the multilayer piezoelectric actuator element were based on the models shown in FIGS. 10A and 10B, the waveform was a square wave, the frequency was 1 Hz, and the duty ratio was 0.2%. The duty ratio represents duty ratio (%) = drive time at actual displacement / 1 cycle time × 100 (%).

  At this time, the laminated piezoelectric actuator element was driven with the applied voltage and applied current shown in Table 1, and the capacitance (μF), the amount of piezoelectric displacement (μm), and the response rise time (μsec) were measured. The results are shown in Table 4. Response rise time (μsec) is measured by measuring the time until the applied voltage becomes 250V, 125V, or 0V when the applied voltage is changed from 0V to 250V or 125V, or from 250V or 125V to 0V. can get.

  For the laminated piezoelectric actuator elements of Example 2 and Comparative Example 2, the applied voltage and applied current shown in Table 5 and Table 6 were applied, respectively, and the effective current and rise time of the laminated piezoelectric actuator element were measured. The results are shown in Tables 5 and 6.

  From the results shown in Table 5 and Table 6, the laminated piezoelectric actuator element of the present invention (Example 2) is shorter than the piezoelectric actuator element of Comparative Example 2 in both the rise time and fall time. It can be seen that the multilayer piezoelectric actuator element of the present invention has excellent response characteristics and a high response speed.

(A) is a schematic diagram which shows the structure of the lamination | stacking 1 which concerns on 1st Embodiment of this invention, (b) is a figure which shows the electrical equivalent circuit of the lamination type piezoelectric actuator element 1. FIG. (A) is a schematic diagram which shows the structure of the multilayer piezoelectric actuator element which concerns on 2nd Embodiment of this invention, (b) is the structure of the multilayer piezoelectric actuator element which concerns on 3rd Embodiment of this invention. FIG. 2C is a diagram showing an electrical equivalent circuit of the multilayer piezoelectric actuator element. (A) is a schematic diagram showing a structure of a multilayer piezoelectric actuator element according to a fourth embodiment of the present invention, and (b) is a diagram showing an electrical equivalent circuit of the multilayer piezoelectric actuator element 40. is there. (A) And (b) is a schematic diagram which shows the structure of each of the multilayer piezoelectric actuator elements according to the fifth and sixth embodiments of the present invention, and (c) is the multilayer piezoelectric actuator. It is a figure which shows the electrical equivalent circuit of an element. 1 is a diagram illustrating a configuration of a multilayer piezoelectric actuator element of Example 1. FIG. 6 is a diagram illustrating a configuration of a multilayer piezoelectric actuator element of Example 2. FIG. It is a figure which shows the structural example of the conventional lamination type piezoelectric actuator element. It is a figure which shows the structural example of the conventional lamination type piezoelectric actuator element. It is a figure which shows the structural example of the conventional lamination type piezoelectric actuator element. (A) And (b) is a figure which shows the drive conditions of a laminated piezoelectric actuator element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laminated type piezoelectric actuator element 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H Piezoelectric layer 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H, 3I Conductor layer 4 Laminated body 5A, 5B, 5C, 5D, 5E, 5F, 5G, 5H, 5I External connection electrodes 6A, 6B, 6C External electrodes A, B, C, DE, F, G, H Piezoelectric unit 7A AC power supply 7B AC power supply (Earth)
8A, 8B Piezoelectric unit group 20 Multilayer piezoelectric actuator elements 20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20I, 20J
Piezoelectric units 22A, 22B, 22C, 22D, 22E, 22F, 22G, 22H, 22I, 22J
Piezoelectric layer 23A, 23B, 23C, 23D, 23E, 23F, 23G, 23H, 23I, 23J, 23K Conductor layer 24 Laminate 25A, 25B, 25C, 25D, 25E, 25F, 25G, 25H, 25I, 25J, 25K External connection electrode part 26A, 26B, 26C, 26D, 26E External electrode 27A AC power supply part 27B AC power supply part (ground)
28A, 28B, 28C Piezoelectric unit group 30 Multilayer piezoelectric actuator elements 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, 30I, 30J, 30K, 30L, 30M, 30N Piezoelectric units 32A, 32B, 32C, 32D 32E, 32F, 32G, 32H, 32I, 32J, 32K, 32L, 32M, 32N Piezoelectric layers 33A, 33B, 33C, 33D, 33E, 33F, 33G, 33H, 33I, 33J, 33K, 33L, 33M, 33N , 33P Conductor layer 34 Laminate 35A, 35B, 35C, 35D, 35E, 35F, 35G, 35H, 35I, 35J, 35K, 35L, 35M, 35N, 35P External connection electrodes 36A, 36B, 36C, 36D, 36E , 36F, 36G External electrode 37A AC power supply unit 37 B AC power supply (ground)
40 Stacked piezoelectric actuator elements 40A, 40B, 40C, 40D, 40F, 40G, 40H Piezoelectric units 42A, 42B, 42C, 42D, 42E, 42F, 42G, 42H, 42I, 42J
Piezoelectric layers 443A, 43B, 43C, 43D, 43E, 43F, 43G, 43H, 43I, 43J
Conductor layer 44 Laminate 45A, 45B, 45C, 45D, 45E, 45F, 45G, 45H, 45I, 45J
External connection electrodes 46A, 46B, 46C External electrode 47A AC power supply 47B AC power supply (ground)
48A, 48B Piezoelectric unit group 49 Bonding layer 50 Multilayer piezoelectric actuator elements 50A, 50B, 50C, 50D, 50F, 50G, 50H, 50I Piezoelectric units 52A, 52B, 52C, 52D, 52E, 52F, 52G, 52H, 52I
Piezoelectric layer 53A, 53B, 53C, 53D, 53E, 53F, 53G, 53H, 53I, 53J, 53K, 53L Conductor layer 54 Laminate 55A, 55B, 55C, 55D, 55E, 55F, 55G, 55H, 55I, 55J , 55K, 55L External connection electrodes 56A, 56B, 56C, 56D External electrode 57A AC power supply 57B AC power supply (earth)
58A, 58B, 58C Piezoelectric unit group 59A, 59B Bonding layer 60 Multilayer piezoelectric actuator elements 60A, 60B, 60C, 60D, 60F, 60G, 60H, 60I, 60J, 60K, 60L Piezoelectric units 62A, 62B, 62C, 62E, 62F, 62G, 62I, 62J, 62K, 62M, 62N, 62P Piezoelectric layers 63A, 63B, 63C, 63D, 63E, 63F, 63G, 63H, 63I, 63J, 63K, 63L, 63M, 63N, 63P, 63Q Layer 64 Laminate 65A, 65B, 65C, 65D, 65E, 65F, 65G, 65H, 65I, 65J, 65K, 65L, 65M, 65N, 65P, 65Q External connection electrode portions 66A, 66B, 66C, 66D, 66E External Electrode 67A AC power supply unit 67B AC power supply unit Ground)
68A, 68B, 68C, 68D Piezoelectric unit group 69A, 69B, 69C Bonding layer 72 Piezoelectric layer 73 Conductive layers 76A, 76B, 76C External electrode 82 Piezoelectric layer 83 Conductive layers 86A, 86B, 86C External electrodes 88A, 88B Piezoelectric units Group 111 Laminated piezoelectric actuator element 112 Piezoelectric layer 113 Internal electrode layer 114 Laminated body 115 End face 116 External electrode 121 Laminated piezoelectric actuator element 122 Piezoelectric layer 123 Internal electrode layer 124 Laminated body unit 125 Joint portion 126 End faces 127A, 127B External Electrode 131 Laminated piezoelectric actuator element 132 Piezoelectric layer 133 Internal electrode layer 134 Laminated body 135 Insulating layer 136 End face 137 External electrode

Claims (4)

  A plurality of piezoelectric layers and conductor layers are alternately stacked, and each of the plurality of piezoelectric layers includes a plurality of piezoelectric units including the piezoelectric layers and a pair of conductor layers sandwiching the piezoelectric layers. The conductor layer of the first conductor layer and the other conductor layer adjacent to the one conductor layer with the piezoelectric layer interposed therebetween are exposed to the side edges of the conductor layer on the opposite side surfaces, and externally connected. An external electrode connected to the external connection electrode portion, wherein at least a pair of piezoelectric units of the plurality of piezoelectric units are connected in series, and the piezoelectric units connected in series A laminated piezoelectric actuator element comprising AC power supply units at both ends.   The external electrode is continuously arranged along the stacking direction on one side surface along the stacking direction of the stacked body, and the two external electrodes are electrically separated from each other on the other side surface. The multilayer piezoelectric actuator element according to claim 1, wherein the multilayer piezoelectric actuator element is arranged. A plurality of piezoelectric layers and conductor layers are alternately stacked, and the plurality of conductor layers include one conductor layer and another adjacent to the one conductor layer with the piezoelectric layer interposed therebetween. A laminated piezoelectric actuator element unit comprising an external electrode connected to the external connection electrode portion, with the side edges of the conductor layer being exposed on the side surfaces facing each other to form an external connection electrode portion A plurality of stacked piezoelectric actuator elements,
A plurality of laminated piezoelectric actuator element units are connected in series via an adhesive layer, and at least a pair of laminated piezoelectric actuator element units are electrically connected in series, and are electrically connected in series. A laminated piezoelectric actuator element comprising an AC power supply unit at both ends of an actuator element unit.   The external electrodes are arranged continuously along the longitudinal direction on one side surface along the longitudinal direction of the stacked piezoelectric actuator elements connected in series, and two external electrodes are electrically connected to each other on the other side surface. The multilayer piezoelectric actuator element according to claim 3, wherein the multilayer piezoelectric actuator element is arranged so as to be divided.

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