JP2012178462A - Laminated piezoelectric element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated piezoelectric element which is capable of reducing a resistance value in a common external electrode.SOLUTION: A laminated piezoelectric element 1 comprises a laminate 2 in which a plurality of piezoelectric layers 30 are laminated, a first inner electrode 31 and a second inner electrode 32 which are alternately disposed in a first portion 20 of the laminate 2 via the piezoelectric layers 30, a third inner electrode 33 disposed in a second portion 21a of the laminate 2, a first outer electrode 3 provided on a first side face 2e and connected with the first inner electrode 31, a second outer electrode 4 provided on a second side face 2f and connected to the second inner electrode 32 and the third inner electrode 33, a third outer electrode 5a provided on the first side face 2e and connected to the third inner electrode 3, and a fourth outer electrode 6 provided on a second principal surface 2d and connects the second outer electrode 3 and the third outer electrode 5a. The first outer electrode 3 and the third outer electrode 5a are electrically insulated from each other on the first side face 2e.

Description

  The present invention relates to a multilayer piezoelectric element.

  As a conventional multilayer piezoelectric element, for example, one described in Patent Document 1 is known. The multilayer piezoelectric element described in Patent Document 1 has a driving unit in which piezoelectric layers and first and second driving internal electrodes are alternately stacked, and a piezoelectric layer and connecting internal electrodes are stacked. A laminated body having a connection portion; a driving external electrode formed on one side of the laminated body and electrically connected to the first driving internal electrode; and a connecting internal electrode formed on one side of the laminated body; An external electrode for connection that conducts, and a common external electrode that is formed on the other side surface of the laminate and is electrically connected to each of the second drive internal electrode and the connection internal electrode.

JP 2003-37307 A

  In the conventional multilayer piezoelectric element, the connection external electrode and the common external electrode are electrically connected by the connection internal electrode. In a piezoelectric actuator composed of such laminated piezoelectric elements, when this piezoelectric actuator is mounted, an actuator section (drive section) arranged at a position where the conduction path from the connection external electrode to the common external electrode is long. The resistance value of the common external electrode is larger than that of the actuator unit arranged at a position where the conduction path is short. As a result, the rise of the actuator part at the position where the conduction path is long is delayed as compared with the actuator part where the conduction path is short, and thus there is a problem that the response varies in the actuator part.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a multilayer piezoelectric element that can reduce the resistance value of a common external electrode.

  In order to solve the above-described problems, a multilayer piezoelectric element according to the present invention includes a plurality of piezoelectric layers stacked, a pair of first and second end faces facing each other, and a pair of first and second end faces. A pair of first and second main surfaces extending to connect each other in the stacking direction of the plurality of piezoelectric layers and a pair extending to connect the pair of first and second main surfaces and facing each other And a first internal electrode alternately disposed via a plurality of piezoelectric layers on a first portion located between the first and second end faces of the multilayer body, and A second internal electrode, a third internal electrode disposed in a second portion located on the first end face side of the laminate, a first external electrode provided on the first side surface and connected to the first internal electrode, A second external electrode provided on the second side surface and connected to the second internal electrode and the third internal electrode; A third external electrode provided on the first side surface and connected to the third internal electrode; and a fourth external electrode provided on the first main surface and connecting the second external electrode and the third external electrode; The first external electrode and the third external electrode are electrically insulated from each other on the first side surface.

  In this multilayer piezoelectric element, the second external electrode and the third external electrode are electrically connected by the third internal electrode and the fourth external electrode. As a result, the resistance component of the third internal electrode and the resistance component of the fourth external electrode are connected in parallel to the second external electrode and the third external electrode. Thus, by causing the fourth external electrode provided on the first main surface to function as a connection electrode, the resistance value of the common external electrode can be reduced. As a result, it is possible to suppress variation in responsiveness due to the resistance value in the piezoelectric actuator composed of the stacked piezoelectric elements.

  The laminated body has a notch formed at a corner portion of the first side and the first main surface in the first portion, and the first internal electrode and the fourth external electrode are electrically insulated from each other by the notch. It is preferable that According to such a configuration, the first external electrode is formed on the entire surface of the first side surface, and the first external electrode is formed by forming the cutout portion after forming the fourth external electrode on the entire surface of the first main surface. And the fourth external electrode are physically and electrically insulated. Therefore, when forming the first external electrode and the fourth external electrode, the work of performing masking so as to be electrically insulated from each other can be omitted. Therefore, it becomes possible to easily produce a multilayer piezoelectric element.

  The laminated body has a notch formed at a corner portion of the first side and the first main surface in the first portion, and the first internal electrode and the fourth external electrode are electrically insulated from each other by the notch. It is preferable that According to such a configuration, the first external electrode and the third external electrode are physically and electrically insulated by forming the groove after forming the external electrode on the entire first side surface. . Therefore, when forming the first external electrode and the third external electrode, the work of performing masking so as to be electrically insulated from each other can be omitted. Therefore, it becomes possible to easily produce a multilayer piezoelectric element.

  A fourth internal electrode disposed on a third portion located on the second end face side of the multilayer body; and a fifth external electrode provided on the first side surface and connected to the fourth internal electrode. The electrodes connect the second external electrode, the third external electrode, and the fifth external electrode, and the first external electrode and the fifth external electrode are electrically insulated from each other on the first side surface.

  According to the present invention, the resistance value of the common external electrode can be reduced.

1 is a perspective view of a multilayer piezoelectric element according to an embodiment of the present invention. (A) is the sectional view on the aa line in FIG. 1, (b) is the sectional view on the bb line in FIG. It is a perspective view of the piezoelectric actuator comprised from the lamination type piezoelectric element shown in FIG. (A) is a perspective view which shows the conventional laminated piezoelectric element, (b) is the sectional view on the aa line in (a). It is an equivalent circuit diagram including the piezoelectric actuator comprised from the laminated piezoelectric element shown in FIG. FIG. 4 is an equivalent circuit diagram including the piezoelectric actuator shown in FIG. 3. It is a graph which shows the resistance value in the common external electrode of the multilayer piezoelectric element which concerns on this embodiment, and the conventional multilayer piezoelectric element. It is a table | surface which shows the resistance value in the common external electrode of the multilayer piezoelectric element which concerns on this embodiment, and the conventional multilayer piezoelectric element.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is a perspective view showing a multilayer piezoelectric element according to an embodiment of the present invention. 2A is a cross-sectional view taken along the line aa in FIG. 1, and FIG. 2B is a cross-sectional view taken along the line bb in FIG.

  As shown in each drawing, the multilayer piezoelectric element 1 includes a multilayer body 2, a first internal electrode 31, a second internal electrode 32, a third internal electrode (fourth internal electrode) 33, and a first external electrode. 3, a second external electrode 4, third external electrodes (fifth external electrodes) 5 a and 5 b, and a fourth external electrode 6. The multilayer piezoelectric element 1 has a length set to about 36.95 mm to 37.05 mm, a width set to about 1.85 mm to 1.95 mm, and a thickness set to about 0.95 mm to 1.05 mm, for example. Has been.

  The laminated body 2 extends so as to connect the pair of first and second end faces 2a, 2b facing the longitudinal direction of the laminated body 2 and the pair of first and second end faces 2a, 2b. A pair of first and second main surfaces 2c, 2d facing each other in the stacking direction of the piezoelectric layer 30 (described later) and the pair of first and second main surfaces 2c, 2d extend so as to connect to each other and face each other. It has a pair of first and second side surfaces 2e, 2f. The laminate 2 has a long rectangular parallelepiped shape.

The stacked body 2 includes a plurality of piezoelectric layers 30 stacked, and includes a first portion 20, a second portion 21a, and a third portion 21b. The first portion 20 is a portion including a piezoelectrically active active portion (active region), and is positioned between the first and second end faces 2 a and 2 b in the stacked body 2. Specifically, the first portion 20 is located at the central portion of the stacked body 2. In the first portion 20, first internal electrodes 31 and second internal electrodes 32 are alternately stacked via a plurality of piezoelectric layers 30. Each piezoelectric layer 30 is made of, for example, a piezoelectric ceramic material mainly composed of lead zirconate titanate (PZT: Pb (Zr _x , Ti _1-x ) O ₃ ). In the actual multilayer piezoelectric element 1, the piezoelectric layers 30 are integrated so as not to be visually recognized. In the present embodiment, the thickness of each piezoelectric layer 30 is about 10 μm to 50 μm.

  A plurality of (in this case, four) first internal electrodes 31 are arranged at a predetermined interval in the stacking direction of the piezoelectric layers 30. One end of the first internal electrode 31 is drawn out to the first side surface 2e, and is exposed to the first side surface 2e. A plurality of (here, five) second internal electrodes 32 are arranged at a predetermined interval in the stacking direction of the piezoelectric layers 30. One end of the second internal electrode 32 is drawn out to the second side face 2f and is exposed to the second side face 2f. The first internal electrode 31 and the second internal electrode 32 are made of a conductive material mainly composed of silver (Ag) and palladium (Pd). In the present embodiment, the thickness of the first internal electrode 31 and the second internal electrode 32 is about 0.5 μm to 3 μm.

  The first internal electrodes 31 and the second internal electrodes 32 are alternately arranged along the facing direction of the piezoelectric layers 30 so as to face each other with the piezoelectric layers 30 interposed therebetween. The second internal electrode 32 is located on the first main surface 2c side and the second main surface 2d side when viewed in the stacking direction.

  The second portion 21a and the third portion 21b are portions including a piezoelectrically inactive portion (inactive region), and are located on the first end surface 2a side and the second end surface 2b side of the laminate 2, respectively. ing. That is, a pair of the second portion 21a and the third portion 21b is provided so as to sandwich the first portion 20 in the longitudinal direction of the stacked body 2 (the opposing direction of the first and second end faces 2a and 2b). In the second portion 21a and the third portion 21b, a plurality of piezoelectric layers 30 and third internal electrodes 33 are alternately stacked. The second portion 21a and the third portion 21b have the same configuration.

  A plurality of (in this case, nine) third internal electrodes 33 are arranged at predetermined intervals in the stacking direction of the piezoelectric layers 30. One end of the third internal electrode 33 is drawn out to the first side face 2e, and the other end is drawn out to the second side face 2f, and is exposed to the first side face 2e and the second side face 2f. The third internal electrode 33 is physically and electrically insulated from the first internal electrode 31 and the second internal electrode 32. The third internal electrode 33 is a connection electrode that connects the second external electrode 4 and the third external electrodes 5a and 5b. The third internal electrode 33 is made of a conductive material containing silver (Ag) and palladium (Pd) as main components. In the present embodiment, the thickness of the third internal electrode 33 is about 0.5 μm to 3 μm.

  The first external electrode 3 is provided on the first side surface 2e. The first external electrode 3 is formed at a position corresponding to the first portion 20 on the first side surface 2 e and is physically and electrically connected to one end of the first internal electrode 31. The first external electrode 3 is made of a three-layer metal film of Cr, Cu / Ni, and Au. The thickness of the first external electrode 3 is about 0.3 μm to 5.0 μm. Hereinafter, the same applies to the second to fourth external electrodes 4 to 6.

  The second external electrode 4 is provided on the second side surface 2f. The second external electrode 4 is formed over the entire second side surface 2 f and is physically and electrically connected to one end of the second internal electrode 32 and the third internal electrode 33. The second external electrode 4 is a common external electrode connected to both the second internal electrode 32 and the third internal electrode 33.

  The third external electrodes 5a and 5b are provided on the first side surface 2e. The third external electrodes 5a and 5b are formed at positions corresponding to the second portion 21a and the third portion 21b on the first side surface 2e, that is, at both ends in the longitudinal direction of the first side surface 2e. Is physically and electrically connected to one end of the. The third external electrodes 5a and 5b and the first external electrode 3 are electrically insulated from each other on the first side surface 2e.

  The fourth external electrode 6 is provided on the second main surface 2d. The fourth external electrode 6 is formed over the entire surface of the second main surface 2d, and is physically and electrically connected to the second external electrode 4 and the third external electrodes 5a and 5b. That is, the fourth external electrode 6 electrically connects the second external electrode 4 and the third external electrodes 5a and 5b. The fourth external electrode 6 is electrically insulated from the first external electrode 3. The fourth external electrode 6 is a connection electrode that connects the second external electrode 4 and the third external electrodes 5a and 5b. The fourth external electrode 6 serves as a connection surface when connected to a substrate (support) or the like with a conductive adhesive.

  Grooves 34 and 35 are formed between the first external electrode 3 and the third external electrodes 5a and 5b, respectively. That is, the grooves 34 and 35 are formed at the boundary between the first portion 20, the second portion 21a, and the third portion 21b. The grooves 34 and 35 are formed on the first side surface 2 e of the stacked body 2 along the stacking direction of the piezoelectric layers 30. By the grooves 34 and 35, the first external electrode 3 and the third external electrodes 5a and 5b are physically and electrically insulated.

  In the first portion 20 of the stacked body 2, a notch 36 is provided at a corner portion between the side surface 2 e and the main surface 2 d. The notch 36 is formed along the longitudinal direction of the laminate 2 at the corner between the side surface 2e and the main surface 2d, and is provided between the groove 34 and the groove 35. The notch 36 is an inclined surface that is inclined with respect to the side surface 2e and the main surface 2d. The first external electrode 3 and the fourth external electrode 6 are physically and electrically insulated by the notch 36.

  Next, a piezoelectric actuator composed of the multilayer piezoelectric element 1 configured as described above will be described. FIG. 3 is a perspective view showing a piezoelectric actuator composed of the multilayer piezoelectric element shown in FIG. As shown in FIG. 3, the piezoelectric actuator 50 is divided into a plurality (eight in this case) of actuator parts 51 a to 51 h by slits S in which the first portion 20 of the multilayer piezoelectric element 1 extends in parallel with the grooves 34 and 35. ing. The piezoelectric actuator 50 is used as, for example, a liquid discharge head of an ink jet printer.

  In the piezoelectric actuator 50, when a voltage is applied between the first external electrode 3 and the second external electrode 4, a voltage is also applied between the first internal electrode 31 and the second internal electrode 32. In the actuator portions 51a to 51h (first portion 20), an electric field is generated in a region between the first internal electrode 31 and the second internal electrode 32 in the piezoelectric layer 30, and the region is displaced. At this time, in the second portion 21 a and the third portion 21 b, no electric field is generated between the third internal electrodes 33 in the piezoelectric layer 30, so that no displacement occurs.

  Next, a method for manufacturing the multilayer piezoelectric element 1 will be described.

  First, a base paste is prepared by mixing an organic binder, an organic solvent, or the like with a piezoelectric ceramic material mainly composed of lead zirconate titanate, and a green sheet to be the piezoelectric layer 30 is formed using the base paste using a doctor blade method. Molded by Moreover, an organic binder, an organic solvent, etc. are mixed with the metal material which consists of silver and palladium of a predetermined ratio, and the electrically conductive paste for electrode pattern formation is produced.

  Next, each of the electrode patterns corresponding to the first to third internal electrodes 31 to 33 is formed on the green sheet by screen printing using a conductive paste. A green sheet on which electrode patterns corresponding to the first internal electrode 31 and the third internal electrode 33 are formed, a green sheet on which electrode patterns corresponding to the second internal electrode 32 and the third internal electrode 33 are formed, and piezoelectric A green sheet to be the body layer 30 is laminated to produce a laminate green.

  Subsequently, the laminate green is pressed at a predetermined pressure in the stacking direction while being heated at a predetermined temperature (for example, about 60 ° C.), and then the stacked green is cut into a predetermined size. The laminate green is degreased at a predetermined temperature (for example, about 400 ° C.) and then fired at a predetermined temperature (for example, about 1100 ° C.) for a predetermined time to obtain the stack 2.

  Subsequently, three layers of metal films of Cr, Cu / Ni, and Au are formed in this order on the surfaces corresponding to the side surfaces 2e and 2f and the main surface 2d of the multilayer body 2 to form external electrodes. Then, by forming grooves 34 and 35 along the stacking direction on the surface corresponding to the side surface 2e in the multilayer body 2, the external electrodes are divided to form the first external electrode 3 and the third external electrodes 5a and 5b. . In addition, by forming a notch 36 at the corner between the side surface 2e and the main surface 2d of the laminate 2, the external electrode is divided to form the first external electrode 3 and the fourth external electrode 6. Thus, the multilayer piezoelectric element 1 is obtained.

  Next, functions and effects of the multilayer piezoelectric element 1 described above will be described.

  FIG. 4A is a perspective view showing a conventional multilayer piezoelectric element, and FIG. 4B is a cross-sectional view taken along the line aa in FIG. As shown in FIG. 4, the conventional multilayer piezoelectric element 60 includes a corner portion between the first side surface 2e and the first main surface 2d across the first portion 20A, the second portion 21Aa, and the third portion 21Ab of the multilayer body 2A. A notch 36A is formed at the top. That is, in the multilayer piezoelectric element 60, the first external electrode 3, the third external electrodes 5Aa, 5Ab, and the fourth external electrode 6A are physically and electrically insulated. Therefore, in the multilayer piezoelectric element 60, the second external electrode 4 and the third external electrodes 5Aa and 5Ab are electrically connected by the third internal electrode 33. The piezoelectric actuator composed of such a laminated piezoelectric element 60 has the following problems.

  FIG. 5 is a diagram showing an equivalent circuit including a piezoelectric actuator composed of stacked piezoelectric elements. As shown in FIG. 5, in the piezoelectric actuator 61 composed of the laminated piezoelectric element 60, power is supplied from the power sources D1 and D2 to the actuator sections 61a, 61b, 61e, 61f, and 61h, and the switches are switched. Thus, the driving of the actuator portions 61a, 61b, 61e, 61f, 61h is controlled. In such a configuration, a portion having a long line length (conduction path) from the power sources D1 and D2, that is, a portion having a short line length from the power sources D1 and D2, for example, the actuator portion 61e located in the central portion of the laminate 2A. That is, since the resistance value is increased by the amount of resistance components connected in series (R1 + R2 +... + R3, R4 +. This will slow down the response. Therefore, the piezoelectric actuator 61 composed of the conventional multilayer piezoelectric element 60 has a problem that the response varies.

  On the other hand, in the multilayer piezoelectric element 1 according to this embodiment, the second external electrode 4 and the third external electrodes 5a and 5b are electrically connected by the third internal electrode 33 and the fourth external electrode 6. Yes. Accordingly, the fourth external electrode 6 functions as a connection electrode together with the third internal electrode 33. Therefore, in the piezoelectric actuator 50 constituted by the multilayer piezoelectric element 1, as shown in FIG. 6, the resistance components R2 to R5 of the third internal electrode 33 and the resistance components R11 to R14 of the fourth external electrode 6 are the second. The external electrode 4 and the third external electrodes 5a and 5b are connected in parallel. Thereby, for example, the resistance value (common resistance) of the common external electrode in, for example, the actuator portion 51e located in the central portion of the multilayer body 2 can be reduced. Therefore, the delay in the rise can be eliminated, and as a result, the variation in response can be suppressed.

  FIG. 7 is a graph showing the resistance value of the common external electrode of the multilayer piezoelectric element according to this embodiment and the conventional multilayer piezoelectric element. FIG. 8 is a graph showing the resistance value of the multilayer piezoelectric element according to this embodiment and the conventional piezoelectric element. It is a table | surface which shows the resistance value in a common external electrode with a lamination type piezoelectric element. As shown in FIGS. 7 and 8, in the multilayer piezoelectric element 1, the Au film thickness (the thickness of the external electrode) is changed as compared with the conventional multilayer piezoelectric element 60 shown in FIG. However, the resistance value is small. Specifically, the multilayer piezoelectric element 1 has a resistance value of −8.8% when the Au film thickness is 0.74 μm and the resistance value when the Au film thickness is 0.94 μm, compared to the conventional multilayer piezoelectric element 60. However, when the Au film thickness is 1.15 μm, the resistance value is reduced by -15.3%. Therefore, the effect becomes remarkable as the Au film thickness increases.

  Here, in order to reduce the resistance value of the common external electrode, it is conceivable to provide external electrodes on the first and second end faces 2 a and 2 b of the multilayer body 2. However, such a configuration causes the following problems. That is, when external electrodes are formed on the first and second end faces 2a and 2b of the laminate 2, when the piezoelectric actuator composed of the laminated piezoelectric element is mounted on a mounting substrate or the like by soldering, it is formed on the end face. In some cases, the solder wraps around the external electrode side, and irregularities are formed on the end face side. The end face of the laminated body is used for positioning when mounting. For this reason, if the end surface is uneven when the piezoelectric actuator is mounted, positioning may be uncertain.

  In addition, when the piezoelectric actuator is mounted, if an external electrode is formed on the end face side, a short circuit may occur between adjacent metal members and the like. Therefore, a metal member or the like cannot be disposed close to the end face side of the laminate. Therefore, when the piezoelectric actuator must be mounted in a limited space, there arises a problem that the space cannot be effectively used.

  On the other hand, in the multilayer piezoelectric element 1, since the external electrodes are not formed on the end surfaces 2a and 2b of the multilayer body 2, the solder does not wrap around the first and second end surfaces 2a and 2b, It is possible to prevent positioning problems due to wraparound. In addition, since metal parts and members can be arranged on both sides of the multilayer piezoelectric element 1 in the longitudinal direction, the parts can be efficiently arranged in a limited space, and the space can be effectively utilized. it can.

  In addition, since the resistance value of the common external electrode can be reduced by securing a conduction path by the fourth external electrode 6, the width of the third internal electrode 33 is narrowed in the second portion 21a and the third portion 21b. be able to. Thereby, the length dimension of the 2nd part 21a and the 3rd part 21b can be made small. Therefore, the length dimension of the multilayer piezoelectric element 1 can be reduced while maintaining the length dimension of the first portion 20. As a result, the multilayer piezoelectric element 1 can be reduced in size.

  Further, since the cutouts 36 are formed at the corners of the side surface 2e and the main surface 2d of the multilayer body 2, when the first external electrode 3 and the fourth external electrode 6 are formed, the first external electrode 3 and the fourth external electrode are formed. Masking or the like for electrically insulating the electrode 6 is not required. That is, the first external electrode 3 is formed on the entire surface of the first side surface 2e and the fourth external electrode 6 is formed on the entire surface of the second main surface 2d, and then the notch 36 is formed, thereby forming the first external electrode. 3 and the fourth external electrode 6 can be physically and electrically insulated. Therefore, the multilayer piezoelectric element 1 can be easily manufactured.

  Furthermore, in the multilayer piezoelectric element 1, unlike the conventional multilayer piezoelectric element 60, the notch portion 36 </ b> A is not formed in the second portion 21 </ b> Aa and the third portion 21 </ b> Ab. The contact area between the substrate and the fourth external electrode 6 can be increased. Thereby, adhesion with a board | substrate (support body) can be made more reliable.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the stacked body 2 is provided with the second portion 21a and the third portion 21b so as to sandwich the first portion 20, but the stacked body 2 includes the first portion 20 and the second portion 21a or It is sufficient that at least one third portion 21b is provided.

  DESCRIPTION OF SYMBOLS 1 ... Laminated piezoelectric element, 2 ... Laminated body, 2a, 2b ... End surface, 2c, 2d ... Side surface, 2e, 2f ... Main surface, 3 ... 1st external electrode, 4 ... 2nd external electrode, 5a, 5b ... 1st 3 external electrode (fifth external electrode), 6... 4th external electrode, 20... 1st portion, 21a... 2nd portion, 21b. ... 3rd internal electrode (4th internal electrode), 34, 35 ... groove | channel, 36 ... notch part.

Claims (4)

A plurality of piezoelectric layers are stacked and extend so as to connect the pair of first and second end faces facing each other and the pair of first and second end faces and in the stacking direction of the plurality of piezoelectric layers. A laminate having a pair of first and second main surfaces facing each other, and a pair of first and second side surfaces extending to connect the pair of first and second main surfaces and facing each other;
A first internal electrode and a second internal electrode alternately disposed via a plurality of piezoelectric layers in a first portion located between the first and second end faces of the laminate;
A third internal electrode disposed in a second portion located on the first end face side of the laminate,
A first external electrode provided on the first side surface and connected to the first internal electrode;
A second external electrode provided on the second side surface and connected to the second internal electrode and the third internal electrode;
A third external electrode provided on the first side surface and connected to the third internal electrode;
A fourth external electrode provided on the first main surface and connecting the second external electrode and the third external electrode;
The multilayer piezoelectric element, wherein the first external electrode and the third external electrode are electrically insulated from each other on the first side surface. The laminate is formed with a notch at a corner portion between the first side surface and the first main surface in the first portion,
The multilayer piezoelectric element according to claim 1, wherein the first internal electrode and the fourth external electrode are electrically insulated from each other by the notch. In the laminate, a groove is formed between the first external electrode and the third external electrode on the first side surface,
3. The multilayer piezoelectric element according to claim 1, wherein the first external electrode and the third external electrode are electrically insulated from each other by the groove. A fourth internal electrode disposed in a third portion located on the second end face side of the laminate,
A fifth external electrode provided on the first side surface and connected to the fourth internal electrode;
The fourth external electrode connects the second external electrode to the third external electrode and the fifth external electrode;
The multilayer piezoelectric element according to claim 1, wherein the first external electrode and the fifth external electrode are electrically insulated from each other on the first side surface.

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