JP2024034327A - Piezoelectric element - Google Patents

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JP2024034327A
JP2024034327A JP2022138503A JP2022138503A JP2024034327A JP 2024034327 A JP2024034327 A JP 2024034327A JP 2022138503 A JP2022138503 A JP 2022138503A JP 2022138503 A JP2022138503 A JP 2022138503A JP 2024034327 A JP2024034327 A JP 2024034327A
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via conductor
conductor group
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美帆 加藤
Miho Kato
英也 坂本
Hideya Sakamoto
佳生 太田
Yoshio Ota
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TDK Corp
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Abstract

To provide a piezoelectric element with improved connection reliability.SOLUTION: In a piezoelectric element 10, third regions 62C, 63C, 64C are adjacent to first regions 62A, 63A, 64A and second regions 62B, 63B, 64B, and do not overlap with any of the first regions 62A, 63A, 64A and the second regions 62B, 63B, 64B viewed from the third direction D3. That is, in the piezoelectric element 10, protrusions are smoothed out to be nearly flat by the third regions 62C, 63C, and 64C, thereby achieving high connection reliability.SELECTED DRAWING: Figure 6

Description

本発明は、圧電素子に関する。 The present invention relates to piezoelectric elements.

従来、一対の導体層の間に圧電素体が介在する駆動部を備えた圧電素子が知られており、このような圧電素子においては一対の導体層の間に電圧を印加することで駆動部が変位する（たとえば所定の方向に伸長する）。下記特許文献１に開示された圧電素子は、内部電極が設けられた圧電体層が複数積層された積層構造を有する圧電素体を有し、積層方向において隣り合う内部電極は同一層内に位置する複数のビア導体（ビア導体群）を介して接続されており、かつ、積層方向において隣り合うビア導体群のビア導体は積層方向から見て重畳していない。 Conventionally, piezoelectric elements are known that have a driving section in which a piezoelectric element is interposed between a pair of conductor layers. is displaced (e.g., elongated in a predetermined direction). The piezoelectric element disclosed in Patent Document 1 below has a piezoelectric element body having a laminated structure in which a plurality of piezoelectric layers provided with internal electrodes are laminated, and internal electrodes that are adjacent in the lamination direction are located in the same layer. The via conductors of the via conductor groups that are adjacent to each other in the stacking direction do not overlap when viewed from the stacking direction.

特許６８２５２９０号Patent No. 6825290

発明者らは、ビア導体の接続信頼性について研究を重ね、接続信頼性を高めることができる技術を新たに見出した。 The inventors have repeatedly researched connection reliability of via conductors and discovered a new technique that can improve connection reliability.

本発明の一側面は、接続信頼性の向上が図られた圧電素子を提供することを目的とする。 One aspect of the present invention is to provide a piezoelectric element with improved connection reliability.

本発明の一側面に係る圧電素子は、圧電材料で構成された素体と、該素体内に設けられるとともに第１の方向において積層された複数の内部導体層とを備え、第１の方向から見て、複数の内部導体層のうちの極性が異なる内部導体層の部分同士が重なる駆動領域と、複数の内部導体層のうちの極性が同じ内部導体層の部分同士が重なるとともに第１の方向に沿って延びる複数のビア導体を介して接続されている複数の接続領域とを含み、複数のビア導体の第１の方向において隣り合う同士は第１の方向から見て重畳しておらず、複数のビア導体が、接続領域内に収まる第１領域内に位置する第１のビア導体群と、第１のビア導体群とは異なる層内に位置するとともに接続領域内に収まる第２領域内に位置する第２のビア導体群と、第１のビア導体群および第２のビア導体群とは異なる層内に位置するとともに接続領域内に収まる第３領域内に位置する第３のビア導体群とを含み、第１の方向から見て、第１領域と第２領域とは少なくとも一部が重畳し、かつ、第３領域は第１領域および第２領域と隣り合っており、第１の方向において、第１のビア導体群、第２のビア導体群および第３のビア導体群のうちの異なるビア導体群同士が隣り合っている。 A piezoelectric element according to one aspect of the present invention includes an element body made of a piezoelectric material, and a plurality of internal conductor layers provided in the element body and laminated in a first direction, As seen, there is a drive region where portions of the inner conductor layers with different polarities among the plurality of inner conductor layers overlap, and a drive region where portions of the inner conductor layers with the same polarity among the plurality of inner conductor layers overlap with each other and a first direction. a plurality of connection regions connected via a plurality of via conductors extending along a plurality of via conductors, the plurality of via conductors adjacent in the first direction do not overlap when viewed from the first direction; A plurality of via conductors include a first via conductor group located in a first region that falls within the connection region, and a second via conductor group that is located in a different layer from the first via conductor group and that falls within the connection region. a second via conductor group located in the second via conductor group, and a third via conductor located in a third region located in a different layer from the first via conductor group and the second via conductor group and falling within the connection region. When viewed from the first direction, the first region and the second region at least partially overlap, the third region is adjacent to the first region and the second region, and the third region is adjacent to the first region and the second region, and the third region is adjacent to the first region and the second region. In the direction, different via conductor groups among the first via conductor group, the second via conductor group, and the third via conductor group are adjacent to each other.

発明者らは、第１のビア導体群が位置する第１領域、第２のビア導体群が位置する第２領域および第３のビア導体群が位置する第３領域における各ビア導体の周辺に隆起が生じ得るとの知見を得た。このような隆起が生じた場合であっても、内部導体層間における十分な接続信頼性を維持する必要がある。特に、第１の方向から見て第１領域と第２領域とが重畳する場合にはより大きな隆起が生じ得る。上記圧電素子においては、第１の方向から見て、第３のビア導体群が位置する第３領域が、第１のビア導体群が位置する第１領域および第２のビア導体群が位置する第２領域と隣り合っており、第１領域および第２領域のいずれとも重畳していない。すなわち、上記圧電素子では、第３領域により上記隆起が平らに近づくように均されており、それにより接続信頼性の向上が図られている。 The inventors have proposed the following method: around each via conductor in a first region where the first via conductor group is located, a second region where the second via conductor group is located, and a third region where the third via conductor group is located. It was found that bumps may occur. Even when such protrusions occur, it is necessary to maintain sufficient connection reliability between the internal conductor layers. Particularly, when the first region and the second region overlap when viewed from the first direction, a larger protrusion may occur. In the above piezoelectric element, when viewed from the first direction, the third area where the third via conductor group is located, the first area where the first via conductor group is located, and the second via conductor group are located. It is adjacent to the second region and does not overlap with either the first region or the second region. That is, in the piezoelectric element, the third region smoothes the protrusion so that it approaches a flat surface, thereby improving connection reliability.

他の側面に係る圧電素子では、第１の方向において、第１のビア導体群と第２のビア導体群とが、第３のビア導体群を介して交互に並んでいる。 In the piezoelectric element according to the other aspect, the first via conductor group and the second via conductor group are arranged alternately in the first direction with the third via conductor group interposed therebetween.

他の側面に係る圧電素子では、第１の方向から見て、第３のビア導体群が位置する第３領域が複数に分かれている。 In the piezoelectric element according to the other aspect, the third region where the third via conductor group is located is divided into a plurality of regions when viewed from the first direction.

他の側面に係る圧電素子では、第１の方向から見て、複数の第３領域が、第１領域および第２領域を挟んでいる。 In the piezoelectric element according to the other aspect, when viewed from the first direction, the plurality of third regions sandwich the first region and the second region.

他の側面に係る圧電素子では、第１の方向から見て、各接続領域内の複数のビア導体すべてが格子の交点に位置している。 In the piezoelectric element according to the other aspect, all of the plurality of via conductors in each connection region are located at the intersections of the lattice when viewed from the first direction.

本発明の種々の側面によれば、接続信頼性の向上が図られた圧電素子が提供される。 According to various aspects of the present invention, a piezoelectric element with improved connection reliability is provided.

図１は、一実施形態に係る圧電素子を示す概略斜視図である。FIG. 1 is a schematic perspective view showing a piezoelectric element according to one embodiment. 図２は、図１に示す圧電素子の平面図である。FIG. 2 is a plan view of the piezoelectric element shown in FIG. 1. 図３は、図１に示す圧電素子の分解斜視図である。FIG. 3 is an exploded perspective view of the piezoelectric element shown in FIG. 1. 図４は、図１に示す圧電素子のＩＶ－ＩＶ線断面図である。FIG. 4 is a cross-sectional view taken along the line IV-IV of the piezoelectric element shown in FIG. 図５は、（ａ）第１のビア導体の配列、（ｂ）第２のビア導体の配列、（ｃ）第３のビア導体の配列を示した図である。FIG. 5 is a diagram showing (a) an arrangement of first via conductors, (b) an arrangement of second via conductors, and (c) an arrangement of third via conductors. 図６は、接続領域における第１～３領域の位置関係を示した図である。FIG. 6 is a diagram showing the positional relationship of the first to third areas in the connection area. 図７は、（ａ）第１のビア導体の配列、（ｂ）第２のビア導体の配列、（ｃ）第３のビア導体の配列を示した図である。FIG. 7 is a diagram showing (a) an arrangement of first via conductors, (b) an arrangement of second via conductors, and (c) an arrangement of third via conductors. 図８は、接続領域における第１～３領域の位置関係を示した図である。FIG. 8 is a diagram showing the positional relationship of the first to third areas in the connection area. 図９は、図４の要部拡大図である。FIG. 9 is an enlarged view of the main part of FIG. 4.

以下、添付図面を参照しつつ本発明を実施するための形態を説明する。図面の説明において、同一又は同等の要素には同一符号を用い、重複する説明は省略する。 Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and overlapping description will be omitted.

図１は一実施形態に係る圧電素子１０を示す斜視図であり、図３は圧電素子１０の平面図である。図１、２に示されるように、圧電素子１０は、バイモルフ型であり、圧電材料で構成された素体１１と、複数の外部電極１３、１４、１５とを備えて構成されている。本実施形態では、圧電素子１０は、三つの外部電極１３、１４、１５を有している。圧電素子１０には、図示しない配線部材（たとえば、フレキシブルプリント基板（ＦＰＣ）、フレキシブルフラットケーブル（ＦＦＣ）等）が取り付けられ、配線部材から三つの外部電極１３、１４、１５に対して所定の電圧が印加される。 FIG. 1 is a perspective view showing a piezoelectric element 10 according to one embodiment, and FIG. 3 is a plan view of the piezoelectric element 10. As shown in FIGS. 1 and 2, the piezoelectric element 10 is of a bimorph type and includes an element body 11 made of a piezoelectric material and a plurality of external electrodes 13, 14, and 15. In this embodiment, the piezoelectric element 10 has three external electrodes 13, 14, and 15. A wiring member (not shown) (for example, a flexible printed circuit board (FPC), a flexible flat cable (FFC), etc.) is attached to the piezoelectric element 10, and a predetermined voltage is applied from the wiring member to the three external electrodes 13, 14, 15. is applied.

素体１１は、直方体形状を呈している。素体１１は、互いに対向している一対の主面１１ａ、１１ｂ、互いに対向している一対の側面１１ｃ、互いに対向している一対の側面１１ｅを有している。直方体形状には、たとえば、角部および稜線部が面取りされている直方体の形状、および、角部および稜線部が丸められている直方体の形状が含まれる。一対の側面１１ｃが対向している方向は、第一方向Ｄ１である。第一方向Ｄ１は、各側面１１ｃに直交する方向でもある。一対の側面１１ｅが対向している方向は、第二方向Ｄ２である。第二方向Ｄ２は、各側面１１ｅに直交する方向でもある。一対の主面１１ａ、１１ｂが対向している方向は、第三方向Ｄ３（第１の方向）である。第三方向Ｄ３は、各主面１１ａ、１１ｂに直交する方向でもある。 The element body 11 has a rectangular parallelepiped shape. The element body 11 has a pair of main surfaces 11a and 11b facing each other, a pair of side faces 11c facing each other, and a pair of side faces 11e facing each other. The rectangular parallelepiped shape includes, for example, a rectangular parallelepiped shape whose corners and edges are chamfered, and a rectangular parallelepiped shape whose corners and edges are rounded. The direction in which the pair of side surfaces 11c are facing is the first direction D1. The first direction D1 is also a direction perpendicular to each side surface 11c. The direction in which the pair of side surfaces 11e are facing is the second direction D2. The second direction D2 is also a direction perpendicular to each side surface 11e. The direction in which the pair of main surfaces 11a and 11b are facing is a third direction D3 (first direction). The third direction D3 is also a direction perpendicular to each main surface 11a, 11b.

各主面１１ａ、１１ｂは、一対の長辺と一対の短辺とを有している。各主面１１ａ、１１ｂは、一対の長辺と一対の短辺とを有する長方形状を呈している。すなわち、圧電素子１０（素体１１）は、平面視で、一対の長辺と一対の短辺とを有する長方形状を呈している。長方形状には、たとえば、各角が面取りされている形状、および、各角が丸められている形状が含まれる。本実施形態では、主面１１ａ、１１ｂの長辺方向は、第二方向Ｄ２と一致する。主面１１ａ、１１ｂの短辺方向は、第一方向Ｄ１方向と一致する。 Each main surface 11a, 11b has a pair of long sides and a pair of short sides. Each main surface 11a, 11b has a rectangular shape with a pair of long sides and a pair of short sides. That is, the piezoelectric element 10 (element body 11) has a rectangular shape having a pair of long sides and a pair of short sides when viewed from above. The rectangular shape includes, for example, a shape in which each corner is chamfered and a shape in which each corner is rounded. In this embodiment, the long side direction of the main surfaces 11a and 11b coincides with the second direction D2. The short side direction of the main surfaces 11a and 11b coincides with the first direction D1.

一対の側面１１ｃは、一対の主面１１ａ、１１ｂを連結するように第三方向Ｄ３に延在している。一対の側面１１ｃは、第二方向Ｄ２にも延在している。一対の側面１１ｅは、一対の主面１１ａ、１１ｂを連結するように第三方向Ｄ３に延在している。一対の側面１１ｅは、第一方向Ｄ１にも延在している。素体１１の第一方向Ｄ１での長さは、たとえば、１０ｍｍである。素体１１の第二方向Ｄ２での長さは、たとえば、２０ｍｍである。素体１１の第三方向Ｄ３での長さは、たとえば、０．２５ｍｍである。各主面１１ａ、１１ｂと各側面１１ｃ、１１ｅとは、間接的に隣り合っていてもよい。この場合、各主面１１ａ、１１ｂと各側面１１ｃ、１１ｅとの間には、稜線部が位置する。 The pair of side surfaces 11c extend in the third direction D3 so as to connect the pair of main surfaces 11a and 11b. The pair of side surfaces 11c also extend in the second direction D2. The pair of side surfaces 11e extend in the third direction D3 so as to connect the pair of main surfaces 11a and 11b. The pair of side surfaces 11e also extend in the first direction D1. The length of the element body 11 in the first direction D1 is, for example, 10 mm. The length of the element body 11 in the second direction D2 is, for example, 20 mm. The length of the element body 11 in the third direction D3 is, for example, 0.25 mm. Each main surface 11a, 11b and each side surface 11c, 11e may be indirectly adjacent to each other. In this case, a ridgeline portion is located between each main surface 11a, 11b and each side surface 11c, 11e.

素体１１では、図３、４に示されるように、複数の圧電体層１６ａ、１７ａ～１７ｈ、１６ｂが、この順で第三方向Ｄ３に積層されている。圧電体層１６ａは、素体１１の主面１１ａを構成する。圧電体層１６ｂは、素体１１の主面１１ｂを構成する。圧電体層１７ａ～１７ｈは、圧電体層１６ａと圧電体層１６ｂとの間に位置している。本実施形態では、圧電体層１６ａ、１６ｂ、１７ａ～１７ｈの厚さは同じである。「同じ」には、製造誤差の範囲が含まれている。 In the element body 11, as shown in FIGS. 3 and 4, a plurality of piezoelectric layers 16a, 17a to 17h, and 16b are laminated in this order in the third direction D3. The piezoelectric layer 16a constitutes the main surface 11a of the element body 11. The piezoelectric layer 16b constitutes the main surface 11b of the element body 11. The piezoelectric layers 17a to 17h are located between the piezoelectric layer 16a and the piezoelectric layer 16b. In this embodiment, the piezoelectric layers 16a, 16b, and 17a to 17h have the same thickness. "Same" includes the range of manufacturing error.

圧電体層１７ａ～１７ｈは、４対で構成されており、すなわち、圧電体層１７ａと圧電体層１７ｂで構成された第１の圧電体層対１８Ａ、圧電体層１７ｃと圧電体層１７ｄで構成された第２の圧電体層対１８Ｂ、圧電体層１７ｅと圧電体層１７ｆで構成された第３の圧電体層対１８Ｃ、圧電体層１７ｇと圧電体層１７ｈで構成された第４の圧電体層対１８Ｄで構成されている。各圧電体層対１８Ａ～１８Ｄを構成する２つの圧電体層の分極の向きは同じである。第１の圧電体層対１８Ａおよび第３の圧電体層対１８Ｃの分極の向きは、第２の圧電体層対１８Ｂおよび第４の圧電体層対１８Ｄの分極の向きと反対である。すなわち、素体１１では、第三方向Ｄ３において、分極の向きが反対の圧電体層対１８Ａ、１８Ｂ、１８Ｃ、１８Ｄが交互に配置されている。 The piezoelectric layers 17a to 17h are composed of four pairs, namely, a first piezoelectric layer pair 18A composed of a piezoelectric layer 17a and a piezoelectric layer 17b, and a first piezoelectric layer pair 18A composed of a piezoelectric layer 17c and a piezoelectric layer 17d. a second piezoelectric layer pair 18B, a third piezoelectric layer pair 18C consisting of a piezoelectric layer 17e and a piezoelectric layer 17f, and a fourth piezoelectric layer pair 18C consisting of a piezoelectric layer 17g and a piezoelectric layer 17h. It is composed of a piezoelectric layer pair 18D. The polarization directions of the two piezoelectric layers constituting each piezoelectric layer pair 18A to 18D are the same. The polarization directions of the first piezoelectric layer pair 18A and the third piezoelectric layer pair 18C are opposite to the polarization directions of the second piezoelectric layer pair 18B and the fourth piezoelectric layer pair 18D. That is, in the element body 11, piezoelectric layer pairs 18A, 18B, 18C, and 18D having opposite polarization directions are alternately arranged in the third direction D3.

各圧電体層１６ａ、１６ｂ、１７ａ～１７ｈは、圧電材料からなる。本実施形態では、各圧電体層１６ａ、１６ｂ、１７ａ～１７ｈは、圧電セラミック材料からなる。圧電セラミック材料には、たとえば、ＰＺＴ［Ｐｂ（Ｚｒ、Ｔｉ）Ｏ３］、ＰＴ（ＰｂＴｉＯ３）、ＰＬＺＴ［（Ｐｂ、Ｌａ）（Ｚｒ、Ｔｉ）Ｏ３］、又はチタン酸バリウム（ＢａＴｉＯ３）が用いられる。各圧電体層１６ａ、１６ｂ、１７ａ～１７ｈは、たとえば、上述した圧電セラミック材料を含むセラミックグリーンシートの焼結体から構成される。実際の素体１１では、各圧電体層１６ａ、１６ｂ、１７ａ～１７ｈは層間の境界が認識できない程度に一体化されている。 Each piezoelectric layer 16a, 16b, 17a to 17h is made of a piezoelectric material. In this embodiment, each piezoelectric layer 16a, 16b, 17a to 17h is made of a piezoelectric ceramic material. Piezoelectric ceramic materials include, for example, PZT[Pb(Zr,Ti) O3 ], PT( PbTiO3 ), PLZT[(Pb,La)(Zr,Ti) O3 ], or barium titanate ( BaTiO3 ). is used. Each piezoelectric layer 16a, 16b, 17a to 17h is composed of, for example, a sintered body of a ceramic green sheet containing the above-mentioned piezoelectric ceramic material. In the actual element body 11, the piezoelectric layers 16a, 16b, 17a to 17h are integrated to such an extent that the boundaries between the layers cannot be recognized.

各外部電極１３、１４は、第三方向Ｄ３から見て、長方形状を呈している。長方形状には、たとえば、各角が面取りされている形状、および、各角が丸められている形状が含まれる。本実施形態では、長方形状の各角が丸められている。外部電極１５は、第三方向Ｄ３から見て、正方形状を呈している。正方形状には、たとえば、各角が面取りされている形状、および、各角が丸められている形状が含まれる。本実施形態では、正方形状の各角が丸められている。各外部電極１３、１４、１５は、導電性材料からなる。導電性材料には、たとえば、Ａｇ、Ｐｄ、Ｐｔ、又はＡｇ－Ｐｄ合金が用いられる。各外部電極１３、１４、１５は、たとえば、上記導電性材料を含む導電性ペーストの焼結体として構成されている。 Each external electrode 13, 14 has a rectangular shape when viewed from the third direction D3. The rectangular shape includes, for example, a shape in which each corner is chamfered and a shape in which each corner is rounded. In this embodiment, each corner of the rectangle is rounded. The external electrode 15 has a square shape when viewed from the third direction D3. The square shape includes, for example, a shape in which each corner is chamfered and a shape in which each corner is rounded. In this embodiment, each corner of the square shape is rounded. Each external electrode 13, 14, 15 is made of a conductive material. For example, Ag, Pd, Pt, or an Ag-Pd alloy is used as the conductive material. Each of the external electrodes 13, 14, and 15 is configured, for example, as a sintered body of conductive paste containing the above-mentioned conductive material.

圧電素子１０は、図３、４に示されるように、素体１１内に配置されている複数の内部導体層２１～２９を備えている。各内部導体層２１～２９は、導電性材料からなる。導電性材料には、たとえば、Ａｇ、Ｐｄ、Ｐｔ、又はＡｇ－Ｐｄ合金が用いられる。各内部導体層２１～２９は、たとえば、上記導電性材料を含む導電性ペーストの焼結体として構成されている。 The piezoelectric element 10, as shown in FIGS. 3 and 4, includes a plurality of internal conductor layers 21 to 29 arranged within the element body 11. Each inner conductor layer 21-29 is made of a conductive material. For example, Ag, Pd, Pt, or an Ag-Pd alloy is used as the conductive material. Each of the internal conductor layers 21 to 29 is configured, for example, as a sintered body of conductive paste containing the above-mentioned conductive material.

各内部導体層２１～２９は、第三方向Ｄ３において異なる位置（層）に配置されている。内部導体層２１～２９は、第三方向Ｄ３において互いに間隔を有しており、少なくとも一部が互いに対向している。各内部導体層２１～２９は、素体１１の表面には露出していない。すなわち、各内部導体層２１～２９は、各側面１１ｃ、１１ｅには露出していない。各内部導体層２１～２９は、第三方向Ｄ３から見て、主面１１ａ、１１ｂの全ての縁（四辺）から離間している。 Each of the internal conductor layers 21 to 29 is arranged at different positions (layers) in the third direction D3. The inner conductor layers 21 to 29 are spaced apart from each other in the third direction D3, and at least a portion thereof faces each other. Each of the internal conductor layers 21 to 29 is not exposed on the surface of the element body 11. That is, each of the internal conductor layers 21 to 29 is not exposed to each side surface 11c, 11e. Each of the internal conductor layers 21 to 29 is spaced apart from all edges (four sides) of the main surfaces 11a and 11b when viewed from the third direction D3.

内部導体層２１は、圧電体層１６ａと圧電体層１７ａとの間に位置している。内部導体層２１は、長方形状の外形を有する駆動部３２と、第三方向Ｄ３から見て外部電極１３、１４と同一形状を有するとともに外部電極１３、１４と完全に重なる位置に配置された接続部３３、３４とが、同一層内に配置された構成を有する。接続部３３、３４はいずれも、第三方向Ｄ３から見て、長方形状を呈している。長方形状には、たとえば、各角が面取りされている形状、および、各角が丸められている形状が含まれる。本実施形態では、長方形状の各角が丸められている。接続部３３、３４は、駆動部３２に形成された開口内に位置している。開口は、第三方向Ｄ３から見て、外部電極１３、１４に対応する位置に形成されており、接続部３３と接続部３４とは同じ開口内に隣り合って位置している。すなわち、接続部３３、３４は、第三方向Ｄ３から見て、駆動部３２に囲まれている。接続部３３、３４は、駆動部３２と離間している。 Internal conductor layer 21 is located between piezoelectric layer 16a and piezoelectric layer 17a. The inner conductor layer 21 includes a drive part 32 having a rectangular outer shape, and a connection having the same shape as the outer electrodes 13 and 14 when viewed from the third direction D3 and located at a position completely overlapping with the outer electrodes 13 and 14. The portions 33 and 34 are arranged in the same layer. Both the connecting portions 33 and 34 have a rectangular shape when viewed from the third direction D3. The rectangular shape includes, for example, a shape in which each corner is chamfered and a shape in which each corner is rounded. In this embodiment, each corner of the rectangle is rounded. The connecting parts 33 and 34 are located within the opening formed in the driving part 32. The opening is formed at a position corresponding to the external electrodes 13 and 14 when viewed from the third direction D3, and the connecting portion 33 and the connecting portion 34 are located adjacent to each other within the same opening. That is, the connecting parts 33 and 34 are surrounded by the driving part 32 when viewed from the third direction D3. The connecting parts 33 and 34 are spaced apart from the driving part 32.

内部導体層２２は、圧電体層１７ａと圧電体層１７ｂとの間に位置している。内部導体層２２は、第三方向Ｄ３から見て外部電極１３、１４、１５と同一形状を有するとともに外部電極１３、１４、１５と完全に重なる位置に配置された接続部３３、３４、３５が、同一層内に配置された構成を有する。 Internal conductor layer 22 is located between piezoelectric layer 17a and piezoelectric layer 17b. The inner conductor layer 22 has the same shape as the outer electrodes 13, 14, 15 when viewed from the third direction D3, and has connecting portions 33, 34, 35 disposed at positions completely overlapping with the outer electrodes 13, 14, 15. , have a configuration arranged in the same layer.

内部導体層２３は、圧電体層１７ｂと圧電体層１７ｃとの間に位置している。内部導体層２３は、長方形状の外形を有する駆動部３２と、第三方向Ｄ３から見て外部電極１３、１５と同一形状を有するとともに外部電極１３、１５と完全に重なる位置に配置された接続部３３、３５とが、同一層内に配置された構成を有する。接続部３５は、第三方向Ｄ３から見て、正方形状を呈している。正方形状には、たとえば、各角が面取りされている形状、および、各角が丸められている形状が含まれる。本実施形態では、正方形状の各角が丸められている。接続部３３、３５は、駆動部３２に形成された開口内に位置している。各開口は、第三方向Ｄ３から見て、外部電極１３、１５に対応する位置に形成されている。すなわち、接続部３３、３５は、第三方向Ｄ３から見て、駆動部３２に囲まれている。接続部３３、３５は、駆動部３２と離間している。 Internal conductor layer 23 is located between piezoelectric layer 17b and piezoelectric layer 17c. The inner conductor layer 23 has a drive part 32 having a rectangular outer shape, and a connection having the same shape as the outer electrodes 13 and 15 when viewed from the third direction D3 and located at a position completely overlapping with the outer electrodes 13 and 15. The portions 33 and 35 are arranged in the same layer. The connecting portion 35 has a square shape when viewed from the third direction D3. The square shape includes, for example, a shape in which each corner is chamfered and a shape in which each corner is rounded. In this embodiment, each corner of the square shape is rounded. The connecting parts 33 and 35 are located within the opening formed in the driving part 32. Each opening is formed at a position corresponding to the external electrodes 13 and 15 when viewed from the third direction D3. That is, the connecting parts 33 and 35 are surrounded by the driving part 32 when viewed from the third direction D3. The connecting parts 33 and 35 are spaced apart from the driving part 32.

内部導体層２４は、圧電体層１７ｃと圧電体層１７ｄとの間に位置している。内部導体層２４は、内部導体層２２同様、第三方向Ｄ３から見て外部電極１３、１４、１５と同一形状を有するとともに外部電極１３、１４、１５と完全に重なる位置に配置された接続部３３、３４、３５が、同一層内に配置された構成を有する。 The internal conductor layer 24 is located between the piezoelectric layer 17c and the piezoelectric layer 17d. Like the internal conductor layer 22, the internal conductor layer 24 has the same shape as the external electrodes 13, 14, 15 when viewed from the third direction D3, and has a connecting portion disposed at a position completely overlapping with the external electrodes 13, 14, 15. 33, 34, and 35 are arranged in the same layer.

内部導体層２５は、圧電体層１７ｄと圧電体層１７ｅとの間に位置している。内部導体層２５は、内部導体層２１と同様の構成を有し、長方形状の外形を有する駆動部３２と、第三方向Ｄ３から見て外部電極１３、１４と同一形状を有するとともに外部電極１３、１４と完全に重なる位置に配置された接続部３３、３４とが、同一層内に配置された構成を有する。 The internal conductor layer 25 is located between the piezoelectric layer 17d and the piezoelectric layer 17e. The inner conductor layer 25 has the same configuration as the inner conductor layer 21, includes a drive part 32 having a rectangular outer shape, and has the same shape as the outer electrodes 13 and 14 when viewed from the third direction D3. , 14 are arranged in the same layer.

内部導体層２６は、圧電体層１７ｅと圧電体層１７ｆとの間に位置している。内部導体層２６は、内部導体層２２、２４同様、第三方向Ｄ３から見て外部電極１３、１４、１５と同一形状を有するとともに外部電極１３、１４、１５と完全に重なる位置に配置された接続部３３、３４、３５が、同一層内に配置された構成を有する。 The internal conductor layer 26 is located between the piezoelectric layer 17e and the piezoelectric layer 17f. Like the internal conductor layers 22 and 24, the internal conductor layer 26 has the same shape as the external electrodes 13, 14, and 15 when viewed from the third direction D3, and is arranged at a position completely overlapping with the external electrodes 13, 14, and 15. The connecting portions 33, 34, and 35 are arranged in the same layer.

内部導体層２７は、圧電体層１７ｆと圧電体層１７ｇとの間に位置している。内部導体層２７は、長方形状の外形を有する駆動部３２と、第三方向Ｄ３から見て外部電極１４、１５と同一形状を有するとともに外部電極１４、１５と完全に重なる位置に配置された接続部３４、３５とが、同一層内に配置された構成を有する。具体的には、接続部３４、３５は、駆動部３２に形成された開口内に位置している。各開口は、第三方向Ｄ３から見て、外部電極１４、１５に対応する位置に形成されている。すなわち、接続部３４、３５は、第三方向Ｄ３から見て、駆動部３２に囲まれている。接続部３４、３５は、駆動部３２と離間している。 The internal conductor layer 27 is located between the piezoelectric layer 17f and the piezoelectric layer 17g. The inner conductor layer 27 has a drive part 32 having a rectangular outer shape, and a connection having the same shape as the outer electrodes 14 and 15 when viewed from the third direction D3 and arranged at a position completely overlapping with the outer electrodes 14 and 15. The portions 34 and 35 are arranged in the same layer. Specifically, the connecting parts 34 and 35 are located within an opening formed in the driving part 32. Each opening is formed at a position corresponding to the external electrodes 14 and 15 when viewed from the third direction D3. That is, the connecting parts 34 and 35 are surrounded by the driving part 32 when viewed from the third direction D3. The connecting parts 34 and 35 are spaced apart from the driving part 32.

内部導体層２８は、圧電体層１７ｇと圧電体層１７ｈとの間に位置している。内部導体層２８は、内部導体層２２、２４、２６同様、第三方向Ｄ３から見て外部電極１３、１４、１５と同一形状を有するとともに外部電極１３、１４、１５と完全に重なる位置に配置された接続部３３、３４、３５が、同一層内に配置された構成を有する。 The internal conductor layer 28 is located between the piezoelectric layer 17g and the piezoelectric layer 17h. Like the internal conductor layers 22, 24, and 26, the internal conductor layer 28 has the same shape as the external electrodes 13, 14, and 15 when viewed from the third direction D3, and is arranged at a position completely overlapping with the external electrodes 13, 14, and 15. The connecting portions 33, 34, and 35 are arranged in the same layer.

内部導体層２９は、圧電体層１７ｈと圧電体層１６ｂとの間に位置している。内部導体層２９は、内部導体層２１、２５と同様の構成を有し、長方形状の外形を有する駆動部３２と、第三方向Ｄ３から見て外部電極１３、１４と同一形状を有するとともに外部電極１３、１４と完全に重なる位置に配置された接続部３３、３４とが、同一層内に配置された構成を有する。 The internal conductor layer 29 is located between the piezoelectric layer 17h and the piezoelectric layer 16b. The inner conductor layer 29 has the same configuration as the inner conductor layers 21 and 25, and has the same shape as the driving part 32 having a rectangular outer shape and the outer electrodes 13 and 14 when viewed from the third direction D3. The electrodes 13 and 14 and the connecting portions 33 and 34 placed at positions completely overlapping each other are arranged in the same layer.

外部電極１３は、内部導体層２７の駆動部３２とその他の内部導体層２１～２６、２８、２９の各接続部３３とに、複数のビア導体４３を介して電気的に接続されている。各接続部３３は、第三方向Ｄ３において内部導体層２７の駆動部３２と対向しており、第三方向Ｄ３から見て内部導体層２７の駆動部３２と重なる位置に配置されている。図４に示すように、複数のビア導体４３は、外部電極１３と内部導体層２１～２６、２８、２９の各接続部３３と内部導体層２７の駆動部３２との間にそれぞれ位置しており、第三方向Ｄ３から見て外部電極１３と重なる位置に配置されている。複数のビア導体４３は、それぞれ、第三方向Ｄ３において、対応する圧電体層１６ａ、１７ａ～１７ｈを貫通している。第三方向Ｄ３において隣り合うビア導体４３同士は、第三方向Ｄ３から見て重畳しないように設計されている。 The external electrode 13 is electrically connected to the drive section 32 of the internal conductor layer 27 and each connection section 33 of the other internal conductor layers 21 to 26, 28, and 29 via a plurality of via conductors 43. Each connection portion 33 faces the drive portion 32 of the internal conductor layer 27 in the third direction D3, and is disposed at a position overlapping the drive portion 32 of the internal conductor layer 27 when viewed from the third direction D3. As shown in FIG. 4, the plurality of via conductors 43 are located between the outer electrode 13, each connection portion 33 of the inner conductor layers 21 to 26, 28, and 29, and the drive portion 32 of the inner conductor layer 27. and is arranged at a position overlapping with the external electrode 13 when viewed from the third direction D3. Each of the plurality of via conductors 43 penetrates the corresponding piezoelectric layer 16a, 17a to 17h in the third direction D3. Via conductors 43 adjacent in the third direction D3 are designed so as not to overlap when viewed from the third direction D3.

外部電極１４は、内部導体層２３の駆動部３２とその他の内部導体層２１～２６、２８、２９の各接続部３４とに、複数のビア導体４４を介して電気的に接続されている。各接続部３４は、第三方向Ｄ３において内部導体層２３の駆動部３２と対向しており、第三方向Ｄ３から見て内部導体層２３の駆動部３２と重なる位置に配置されている。図４に示すように、複数のビア導体４４は、それぞれ、外部電極１４と内部導体層２１、２２、２４～２９の各接続部３４と内部導体層２３の駆動部３２との間に位置しており、第三方向Ｄ３から見て外部電極１４と重なる位置に配置されている。複数のビア導体４４は、それぞれ、第三方向Ｄ３において、対応する圧電体層１６ａ、１７ａ～１７ｈを貫通している。第三方向Ｄ３において隣り合うビア導体４４同士は、第三方向Ｄ３から見て重畳しないように設計されている。 The external electrode 14 is electrically connected to the drive section 32 of the internal conductor layer 23 and each connection section 34 of the other internal conductor layers 21 to 26, 28, and 29 via a plurality of via conductors 44. Each connection portion 34 faces the drive portion 32 of the internal conductor layer 23 in the third direction D3, and is disposed at a position overlapping the drive portion 32 of the internal conductor layer 23 when viewed from the third direction D3. As shown in FIG. 4, the plurality of via conductors 44 are located between the outer electrode 14 and each connection portion 34 of the inner conductor layers 21, 22, 24 to 29, and the drive portion 32 of the inner conductor layer 23. It is arranged at a position overlapping with the external electrode 14 when viewed from the third direction D3. Each of the plurality of via conductors 44 penetrates the corresponding piezoelectric layer 16a, 17a to 17h in the third direction D3. Via conductors 44 adjacent in the third direction D3 are designed so as not to overlap when viewed from the third direction D3.

外部電極１５は、内部導体層２３、２７の各接続部３５と内部導体層２１、２５、２９の駆動部３２とに、複数のビア導体４５を介して電気的に接続されている。各接続部３５は、第三方向Ｄ３において内部導体層２１、２５、２９の駆動部３２と対向しており、第三方向Ｄ３から見て内部導体層２１、２５、２９の駆動部３２と重なる位置に配置されている。複数のビア導体４５は、それぞれ、外部電極１５と内部導体層２３、２７の各接続部３５と内部導体層２１、２５、２９の駆動部３２との間に位置しており、第三方向Ｄ３から見て外部電極１５と重なる位置に配置されている。複数のビア導体４５は、それぞれ、第三方向Ｄ３において、対応する圧電体層１６ａ、１７ａ～１７ｈを貫通している。第三方向Ｄ３において隣り合うビア導体４５同士は、第三方向Ｄ３から見て重畳しないように設計されている。 The external electrode 15 is electrically connected to each connecting portion 35 of the internal conductor layers 23 and 27 and the driving portion 32 of the internal conductive layers 21 , 25 , and 29 via a plurality of via conductors 45 . Each connection portion 35 faces the drive portion 32 of the inner conductor layers 21, 25, 29 in the third direction D3, and overlaps the drive portion 32 of the inner conductor layers 21, 25, 29 when viewed from the third direction D3. placed in position. The plurality of via conductors 45 are respectively located between the outer electrode 15 and each connection portion 35 of the inner conductor layers 23, 27 and the drive portion 32 of the inner conductor layers 21, 25, 29, and are arranged in the third direction D3. It is arranged at a position overlapping with the external electrode 15 when viewed from above. Each of the plurality of via conductors 45 penetrates the corresponding piezoelectric layer 16a, 17a to 17h in the third direction D3. Via conductors 45 adjacent in the third direction D3 are designed so as not to overlap when viewed from the third direction D3.

内部導体層２１～２９およびビア導体４３、４４、４５は、導電性材料からなる。導電性材料には、たとえば、Ａｇ、Ｐｄ、Ｐｔ、又はＡｇ－Ｐｄ合金が用いられる。内部導体層２１～２９およびビア導体４３、４４、４５は、たとえば、上記導電性材料を含む導電性ペーストの焼結体として構成されている。ビア導体４３、４４、４５は、対応する圧電体層１６ａ、１７ａ～１７ｈを形成するためのセラミックグリーンシートに形成された貫通孔に充填された導電性ペーストが焼結することにより形成される。 Inner conductor layers 21-29 and via conductors 43, 44, 45 are made of conductive material. For example, Ag, Pd, Pt, or an Ag-Pd alloy is used as the conductive material. The inner conductor layers 21 to 29 and the via conductors 43, 44, and 45 are configured, for example, as a sintered body of conductive paste containing the above-mentioned conductive material. Via conductors 43, 44, and 45 are formed by sintering conductive paste filled in through holes formed in ceramic green sheets for forming corresponding piezoelectric layers 16a, 17a to 17h.

上述した圧電素子１０は、駆動領域５０と、複数の接続領域６２、６３、６４を含む。 The piezoelectric element 10 described above includes a drive region 50 and a plurality of connection regions 62, 63, and 64.

駆動領域５０は、図３に示すように、第三方向Ｄ３から見て、駆動部３２を含む内部導体層２１、２３、２５、２７、２９（駆動導体層）の駆動部３２同士が重なる領域である。具体的には、駆動領域５０は、外部電極１５に接続されている内部導体層２１、２５、２９の駆動部３２と、外部電極１３に接続されている内部導体層２７および外部電極１４に接続されている内部導体層２３の駆動部３２とが重なる領域である。駆動領域５０は、図４に示すように、外部電極１５に接続されている内部導体層２１、２５と外部電極１４に接続されている内部導体層２３とに挟まれた第１駆動領域５１と、外部電極１５に接続されている内部導体層２５、２９と外部電極１３に接続されている内部導体層２７とに挟まれた第２駆動領域５２とを含む。 As shown in FIG. 3, the driving region 50 is a region where the driving portions 32 of the internal conductor layers 21, 23, 25, 27, and 29 (driving conductor layers) including the driving portions 32 overlap when viewed from the third direction D3. It is. Specifically, the driving region 50 is connected to the driving portion 32 of the internal conductor layers 21 , 25 , 29 connected to the external electrode 15 , and the internal conductive layer 27 connected to the external electrode 13 and the external electrode 14 . This is the region where the drive portion 32 of the internal conductor layer 23 overlaps with the inner conductor layer 23 . As shown in FIG. 4, the drive region 50 includes a first drive region 51 sandwiched between the inner conductor layers 21 and 25 connected to the outer electrode 15 and the inner conductor layer 23 connected to the outer electrode 14. , a second drive region 52 sandwiched between inner conductor layers 25 and 29 connected to the outer electrode 15 and an inner conductor layer 27 connected to the outer electrode 13.

複数の接続領域６２、６３、６４は、図３に示すように、第三方向Ｄ３から見て、極性が同じ部分の内部導体層２１～２９同士が重なる領域である。本実施形態では、複数の接続領域は、第１の接続領域６２、第２の接続領域６３、第３の接続領域６４の３つで構成されている。第１の接続領域６２は、第三方向Ｄ３から見て、内部導体層２１～２６、２８、２９の接続部３３と、接続部３３に対応する部分の内部導体層２７とが重なる領域である。第２の接続領域６３は、第三方向Ｄ３から見て、内部導体層２１、２２、２４～２９の接続部３４と、接続部３４に対応する部分の内部導体層２３とが重なる領域である。第３の接続領域６４は、第三方向Ｄ３から見て、内部導体層２２～２４、２６～２８の接続部３５と、接続部３５に対応する部分の内部導体層２１、２５、２９とが重なる領域である。本実施形態では、第三方向Ｄ３から見て、駆動領域５０が、複数の複数の接続領域６２、６３、６４を囲むように位置している。 As shown in FIG. 3, the plurality of connection regions 62, 63, and 64 are regions where internal conductor layers 21 to 29 having the same polarity overlap each other when viewed from the third direction D3. In this embodiment, the plurality of connection areas includes three connection areas: a first connection area 62 , a second connection area 63 , and a third connection area 64 . The first connection region 62 is a region where the connection portions 33 of the internal conductor layers 21 to 26, 28, and 29 and the portion of the internal conductor layer 27 corresponding to the connection portions 33 overlap when viewed from the third direction D3. . The second connection region 63 is a region where the connection portions 34 of the internal conductor layers 21, 22, 24 to 29 and the portions of the internal conductor layer 23 corresponding to the connection portions 34 overlap when viewed from the third direction D3. . In the third connection region 64, the connection portions 35 of the internal conductor layers 22 to 24 and 26 to 28 and the portions of the internal conductor layers 21, 25, and 29 corresponding to the connection portions 35 are arranged in the third connection region 64. This is an area of overlap. In this embodiment, the drive region 50 is located so as to surround the plurality of connection regions 62, 63, and 64 when viewed from the third direction D3.

続いて、上述した圧電素子１０の駆動について説明する。 Next, driving of the piezoelectric element 10 described above will be explained.

外部電極１３と外部電極１４とには、極性が異なる電圧が印加される。外部電極１５には、外部電極１３、１４に印加されるような電圧は印加されない。外部電極１５は、グラウンド電極として機能する。外部電極１３に上述した電圧が印加されると、内部導体層２５と内部導体層２７との間、内部導体層２７と内部導体層２９との間で電界が発生する。内部導体層２７と内部導体層２５、２９との間で電界が発生すると、第２駆動領域５２の第３の圧電体層対１８Ｃおよび第４の圧電体層対１８Ｄに電界が印加され、当該電界に応じて第２駆動領域５２で力が発生する。この結果、当該力に応じた変位量だけ、第２駆動領域５２が変位する。 Voltages with different polarities are applied to the external electrode 13 and the external electrode 14. The voltage applied to the external electrodes 13 and 14 is not applied to the external electrode 15. External electrode 15 functions as a ground electrode. When the voltage described above is applied to the external electrode 13, an electric field is generated between the internal conductor layer 25 and the internal conductor layer 27 and between the internal conductor layer 27 and the internal conductor layer 29. When an electric field is generated between the inner conductor layer 27 and the inner conductor layers 25 and 29, the electric field is applied to the third piezoelectric layer pair 18C and the fourth piezoelectric layer pair 18D in the second drive region 52, and A force is generated in the second driving region 52 in response to the electric field. As a result, the second drive region 52 is displaced by an amount of displacement corresponding to the force.

外部電極１４に上述した電圧が印加されると、内部導体層２１と内部導体層２３との間、内部導体層２３と内部導体層２５との間で電界が発生する。内部導体層２３と内部導体層２１、２５との間で電界が発生すると、第１駆動領域５１の第１の圧電体層対１８Ａおよび第２の圧電体層対１８Ｂに電界が印加され、当該電界に応じて第１駆動領域５１で力が発生する。この結果、当該力に応じた変位量だけ、第１駆動領域５１が変位する。この際、第１駆動領域５１と第２駆動領域５２とは、互いに逆方向に変位する。このため、外部電極１３、１４に電圧が印加されると、圧電素子１０に撓みが生じる。 When the voltage described above is applied to the external electrode 14, an electric field is generated between the internal conductor layer 21 and the internal conductor layer 23 and between the internal conductor layer 23 and the internal conductor layer 25. When an electric field is generated between the inner conductor layer 23 and the inner conductor layers 21 and 25, the electric field is applied to the first piezoelectric layer pair 18A and the second piezoelectric layer pair 18B in the first drive region 51, and A force is generated in the first driving region 51 in response to the electric field. As a result, the first drive region 51 is displaced by an amount of displacement corresponding to the force. At this time, the first drive region 51 and the second drive region 52 are displaced in opposite directions. Therefore, when a voltage is applied to the external electrodes 13 and 14, the piezoelectric element 10 is deflected.

圧電素子１０では、外部電極１３、１４に交流電圧が印加されると、第１駆動領域５１および第２駆動領域５２は、印加された交流電圧の周波数に応じて伸縮を繰り返す。このため、第１駆動領域５１と第２駆動領域５２とは互いに逆方向に伸縮し、圧電素子１０が撓み振動する。 In the piezoelectric element 10, when an AC voltage is applied to the external electrodes 13 and 14, the first drive area 51 and the second drive area 52 repeat expansion and contraction according to the frequency of the applied AC voltage. Therefore, the first drive region 51 and the second drive region 52 expand and contract in opposite directions, and the piezoelectric element 10 bends and vibrates.

以下、複数のビア導体４３、４４、４５について、図５～８を参照しつつより詳しく説明する。 Hereinafter, the plurality of via conductors 43, 44, and 45 will be explained in more detail with reference to FIGS. 5 to 8.

図４では、図示の都合上、１つのビア導体４３が圧電体層１６ａ、１７ａ～１７ｈをそれぞれ貫通しているように示しているが、実際には、複数のビア導体４３が圧電体層１６ａ、１７ａ～１７ｈをそれぞれ貫通している。 In FIG. 4, for convenience of illustration, one via conductor 43 is shown penetrating each of the piezoelectric layers 16a, 17a to 17h, but in reality, a plurality of via conductors 43 , 17a to 17h, respectively.

複数のビア導体４３は、図５に示すように、同一層内に位置する複数のビア導体４３で構成された第１のビア導体群４３Ａ、同一層内に位置する複数のビア導体４３で構成された第２のビア導体群４３Ｂ、同一層内に位置する複数のビア導体４３で構成された第３のビア導体群４３Ｃの３種類のビア導体群を含んでいる。 As shown in FIG. 5, the plurality of via conductors 43 include a first via conductor group 43A made up of a plurality of via conductors 43 located in the same layer, and a first via conductor group 43A made up of a plurality of via conductors 43 located in the same layer. The via conductor group 43C includes three types of via conductor groups: a second via conductor group 43B made up of a plurality of via conductors 43 located in the same layer, and a third via conductor group 43C made up of a plurality of via conductors 43 located in the same layer.

第１のビア導体群４３Ａは、図５（ａ）に示すように接続領域６２の中央付近に位置する矩形状の第１領域６２Ａ内に収まるように設けられている。第１のビア導体群４３Ａは、第１領域６２Ａにおいて整列する複数のビア導体４３で構成されている。本実施形態では、第１のビア導体群４３Ａは、格子の交点に位置するように配列（格子配列）された２０個のビア導体４３で構成されており、第一方向Ｄ１に等間隔で並ぶ５個のビア導体４３の列が第二方向Ｄ２に等間隔で４列並んでいる。 The first via conductor group 43A is provided so as to fit within a rectangular first region 62A located near the center of the connection region 62, as shown in FIG. 5(a). The first via conductor group 43A is composed of a plurality of via conductors 43 aligned in the first region 62A. In this embodiment, the first via conductor group 43A is composed of 20 via conductors 43 arranged at intersections of a grid (lattice arrangement), and arranged at equal intervals in the first direction D1. Four rows of five via conductors 43 are arranged at equal intervals in the second direction D2.

第２のビア導体群４３Ｂは、図５（ｂ）に示すように接続領域６２の中央付近に位置する矩形状の第２領域６２Ｂ内に収まるように設けられている。第２のビア導体群４３Ｂは、第２領域６２Ｂにおいて整列する複数のビア導体４３で構成されている。本実施形態では、第２のビア導体群４３Ｂは、第１のビア導体群４３Ａ同様、格子配列された２０個のビア導体４３で構成されており、第一方向Ｄ１に等間隔で並ぶ５個のビア導体４３の列が第二方向Ｄ２に等間隔で４列並んでいる。 The second via conductor group 43B is provided so as to fit within a rectangular second region 62B located near the center of the connection region 62, as shown in FIG. 5(b). The second via conductor group 43B is composed of a plurality of via conductors 43 aligned in the second region 62B. In this embodiment, the second via conductor group 43B, like the first via conductor group 43A, is composed of 20 via conductors 43 arranged in a lattice, and includes five via conductors 43 arranged at equal intervals in the first direction D1. Four rows of via conductors 43 are arranged at equal intervals in the second direction D2.

第３のビア導体群４３Ｃは、図５（ｃ）に示すように接続領域６２の両端（第一方向Ｄ１に関する両端）に位置する矩形状の一対の第３領域６２Ｃ内に収まるように設けられている。第３のビア導体群４３Ｃは、各第３領域６２Ｃにおいて整列する複数のビア導体４３で構成されている。本実施形態では、第３のビア導体群４３Ｃは、一対の第３領域６２Ｃのうちの一方に格子配列された１１個と他方に格子配列された９個との総数２０個のビア導体４３で構成されている。 The third via conductor group 43C is provided so as to fit within a pair of rectangular third regions 62C located at both ends of the connection region 62 (both ends in the first direction D1), as shown in FIG. 5(c). ing. The third via conductor group 43C is composed of a plurality of via conductors 43 aligned in each third region 62C. In this embodiment, the third via conductor group 43C includes a total of 20 via conductors 43, 11 in a lattice arrangement on one of the pair of third regions 62C and 9 in a lattice arrangement on the other. It is configured.

図６は、第三方向Ｄ３から見たときの、３つのビア導体群４３Ａ、４３Ｂ、４３Ｃの位置関係を示してる。図６に示すように、第三方向Ｄ３から見ると、３つのビア導体群４３Ａ、４３Ｂ、４３Ｃによって接続領域６２内の複数のビア導体４３すべてが格子配列されている。第三方向Ｄ３から見て、第１のビア導体群４３Ａが位置する第１領域６２Ａと第２のビア導体群４３Ｂが位置する第２領域６２Ｂとは一部が重畳している。より詳しくは、等間隔で並ぶビア導体４３の半分の間隔（半ピッチ）だけ第一方向Ｄ１および第二方向Ｄ２にそれぞれズレた状態で、第１領域６２Ａと第２領域６２Ｂとが重なっている。第三方向Ｄ３から見て、第３のビア導体群４３Ｃが位置する第３領域６２Ｃは、第１領域６２Ａおよび第２領域６２Ｂを挟むようにして第１領域６２Ａおよび第２領域６２Ｂと隣り合っており、第１領域６２Ａおよび第２領域６２Ｂのいずれとも重畳していない。 FIG. 6 shows the positional relationship of the three via conductor groups 43A, 43B, and 43C when viewed from the third direction D3. As shown in FIG. 6, when viewed from the third direction D3, all the plurality of via conductors 43 in the connection region 62 are arranged in a lattice arrangement by the three via conductor groups 43A, 43B, and 43C. When viewed from the third direction D3, the first region 62A where the first via conductor group 43A is located and the second region 62B where the second via conductor group 43B is located partially overlap. More specifically, the first region 62A and the second region 62B overlap with each other in a state shifted in the first direction D1 and the second direction D2 by a half interval (half pitch) of the via conductors 43 arranged at equal intervals. . When viewed from the third direction D3, the third region 62C in which the third via conductor group 43C is located is adjacent to the first region 62A and the second region 62B with the first region 62A and the second region 62B interposed therebetween. , does not overlap with either the first region 62A or the second region 62B.

複数のビア導体４３のうち、第１のビア導体群４３Ａは圧電体層１６ａ、１７ｃ、１７ｇをそれぞれ貫通するように設けられており、第２のビア導体群４３Ｂは圧電体層１７ａ、１７ｅをそれぞれ貫通するように設けられており、第３のビア導体群４３Ｃは圧電体層１７ｂ、１７ｄ、１７ｆ、１７ｈをそれぞれ貫通するように設けられている。特に、圧電体層１７ａ～１７ｈでは、素体１１の主面１１ａ側から順に、第２のビア導体群４３Ｂ、第３のビア導体群４３Ｃ、第１のビア導体群４３Ａ、第３のビア導体群４３Ｃ、第２のビア導体群４３Ｂ、第３のビア導体群４３Ｃ、第１のビア導体群４３Ａ、第３のビア導体群４３Ｃの順に並んでいる。換言すると、複数のビア導体４３は、第三方向Ｄ３において、第２のビア導体群４３Ｂと第１のビア導体群４３Ａとが、第３のビア導体群４３Ｃを介して交互に並んでいる。 Among the plurality of via conductors 43, a first via conductor group 43A is provided to penetrate piezoelectric layers 16a, 17c, and 17g, respectively, and a second via conductor group 43B is provided to penetrate piezoelectric layers 17a and 17e. The third via conductor group 43C is provided so as to penetrate each of the piezoelectric layers 17b, 17d, 17f, and 17h. In particular, in the piezoelectric layers 17a to 17h, in order from the main surface 11a side of the element body 11, the second via conductor group 43B, the third via conductor group 43C, the first via conductor group 43A, and the third via conductor group Group 43C, second via conductor group 43B, third via conductor group 43C, first via conductor group 43A, and third via conductor group 43C. In other words, in the plurality of via conductors 43, second via conductor groups 43B and first via conductor groups 43A are arranged alternately with third via conductor groups 43C interposed therebetween.

複数のビア導体４４は、同一層内に位置する複数のビア導体４４で構成された第１のビア導体群４４Ａ、同一層内に位置する複数のビア導体４４で構成された第２のビア導体群４４Ｂ、同一層内に位置する複数のビア導体４４で構成された第３のビア導体群４４Ｃの３種類のビア導体群を含んでいる。 The plurality of via conductors 44 include a first via conductor group 44A made up of a plurality of via conductors 44 located in the same layer, and a second via conductor group made up of a plurality of via conductors 44 located in the same layer. It includes three types of via conductor groups: a group 44B and a third via conductor group 44C composed of a plurality of via conductors 44 located in the same layer.

複数のビア導体４４の３種類のビア導体群４４Ａ～４４Ｃ、および、各ビア導体群４４Ａ～４４Ｃが位置する第１領域６３Ａ、第２領域６３Ｂおよび第３領域６３Ｃの形態は、複数のビア導体４３の３種類のビア導体群４３Ａ～４３Ｃおよび第１領域６２Ａ、第２領域６２Ｂおよび第３領域６２Ｃの形態と同一または同様であるため、説明は省略する。 The three types of via conductor groups 44A to 44C of the plurality of via conductors 44 and the first region 63A, second region 63B, and third region 63C in which each of the via conductor groups 44A to 44C are located are shaped like a plurality of via conductors. The configurations are the same as or similar to those of the three types of via conductor groups 43A to 43C, the first region 62A, the second region 62B, and the third region 62C of No. 43, and therefore the description thereof will be omitted.

複数のビア導体４４のうち、第１のビア導体群４４Ａは圧電体層１６ａ、１７ｃ、１７ｇをそれぞれ貫通するように設けられており、第２のビア導体群４４Ｂは圧電体層１７ａ、１７ｅをそれぞれ貫通するように設けられており、第３のビア導体群４４Ｃは圧電体層１７ｂ、１７ｄ、１７ｆ、１７ｈをそれぞれ貫通するように設けられている。特に、圧電体層１７ａ～１７ｈでは、素体１１の主面１１ａ側から順に、第２のビア導体群４４Ｂ、第３のビア導体群４４Ｃ、第１のビア導体群４４Ａ、第３のビア導体群４４Ｃ、第２のビア導体群４４Ｂ、第３のビア導体群４４Ｃ、第１のビア導体群４４Ａ、第３のビア導体群４４Ｃの順に並んでいる。換言すると、複数のビア導体４４は、第三方向Ｄ３において、第２のビア導体群４４Ｂと第１のビア導体群４４Ａとが、第３のビア導体群４４Ｃを介して交互に並んでいる。 Among the plurality of via conductors 44, a first via conductor group 44A is provided to penetrate piezoelectric layers 16a, 17c, and 17g, respectively, and a second via conductor group 44B is provided to penetrate piezoelectric layers 17a and 17e. The third via conductor group 44C is provided so as to penetrate each of the piezoelectric layers 17b, 17d, 17f, and 17h. In particular, in the piezoelectric layers 17a to 17h, in order from the main surface 11a side of the element body 11, the second via conductor group 44B, the third via conductor group 44C, the first via conductor group 44A, and the third via conductor group Group 44C, second via conductor group 44B, third via conductor group 44C, first via conductor group 44A, and third via conductor group 44C are arranged in this order. In other words, in the plurality of via conductors 44, second via conductor groups 44B and first via conductor groups 44A are arranged alternately with third via conductor groups 44C in between.

複数のビア導体４５は、同一層内に位置する複数のビア導体４５で構成された第１のビア導体群４５Ａ、同一層内に位置する複数のビア導体４５で構成された第２のビア導体群４５Ｂ、同一層内に位置する複数のビア導体４５で構成された第３のビア導体群４５Ｃの３種類のビア導体群を含んでいる。 The plurality of via conductors 45 include a first via conductor group 45A made up of a plurality of via conductors 45 located in the same layer, and a second via conductor group made up of a plurality of via conductors 45 located in the same layer. It includes three types of via conductor groups: a group 45B and a third via conductor group 45C composed of a plurality of via conductors 45 located in the same layer.

第１のビア導体群４５Ａは、図７（ａ）に示すように接続領域６４の中央付近に位置する矩形状の第１領域６４Ａ内に収まるように設けられている。第１のビア導体群４５Ａは、第１領域６４Ａにおいて整列する複数のビア導体４５で構成されている。本実施形態では、第１のビア導体群４５Ａは、格子配列された４０個のビア導体４５で構成されており、第一方向Ｄ１に等間隔で並ぶ５個のビア導体４５の列が第二方向Ｄ２に等間隔で８列並んでいる。 The first via conductor group 45A is provided so as to fit within a rectangular first region 64A located near the center of the connection region 64, as shown in FIG. 7(a). The first via conductor group 45A is composed of a plurality of via conductors 45 aligned in the first region 64A. In this embodiment, the first via conductor group 45A is composed of 40 via conductors 45 arranged in a lattice, and the rows of five via conductors 45 arranged at equal intervals in the first direction D1 are connected to the second via conductor group 45A. They are arranged in eight rows at equal intervals in direction D2.

第２のビア導体群４５Ｂは、図７（ｂ）に示すように接続領域６４の中央付近に位置する矩形状の第２領域６４Ｂ内に収まるように設けられている。第２のビア導体群４５Ｂは、第２領域６４Ｂにおいて整列する複数のビア導体４５で構成されている。本実施形態では、第２のビア導体群４５Ｂは、第１のビア導体群４５Ａ同様、格子配列された４０個のビア導体４５で構成されており、第一方向Ｄ１に等間隔で並ぶ５個のビア導体４３の列が第二方向Ｄ２に等間隔で８列並んでいる。 The second via conductor group 45B is provided so as to fit within a rectangular second region 64B located near the center of the connection region 64, as shown in FIG. 7(b). The second via conductor group 45B is composed of a plurality of via conductors 45 aligned in the second region 64B. In this embodiment, like the first via conductor group 45A, the second via conductor group 45B is composed of 40 via conductors 45 arranged in a lattice, and includes five via conductors 45 arranged at equal intervals in the first direction D1. Eight rows of via conductors 43 are arranged at equal intervals in the second direction D2.

第３のビア導体群４５Ｃは、図７（ｃ）に示すように接続領域６４の両端（第一方向Ｄ１に関する両端）に位置する矩形状の一対の第３領域６４Ｃ内に収まるように設けられている。第３のビア導体群４５Ｃは、各第３領域６４Ｃにおいて整列する複数のビア導体４５で構成されている。本実施形態では、第３のビア導体群４５Ｃは、一対の第３領域６４Ｃのうちの一方に格子配列された１８個と他方に格子配列された１５個との総数３３個のビア導体４５で構成されている。 The third via conductor group 45C is provided so as to fit within a pair of rectangular third regions 64C located at both ends of the connection region 64 (both ends in the first direction D1), as shown in FIG. 7(c). ing. The third via conductor group 45C is composed of a plurality of via conductors 45 aligned in each third region 64C. In this embodiment, the third via conductor group 45C includes a total of 33 via conductors 45, 18 in a lattice arrangement on one of the pair of third regions 64C and 15 in a lattice arrangement on the other. It is configured.

図８は、第三方向Ｄ３から見たときの、３つのビア導体群４５Ａ、４５Ｂ、４５Ｃの位置関係を示してる。図８に示すように、第三方向Ｄ３から見ると、３つのビア導体群４５Ａ、４５Ｂ、４５Ｃによって接続領域６４内の複数のビア導体４４すべてが格子配列されている。第三方向Ｄ３から見て、第１のビア導体群４５Ａが位置する第１領域６４Ａと第２のビア導体群４５Ｂが位置する第２領域６４Ｂとは一部が重畳している。より詳しくは、等間隔で並ぶビア導体４５の半分の間隔（半ピッチ）だけ第一方向Ｄ１および第二方向Ｄ２にそれぞれズレた状態で、第１領域６４Ａと第２領域６４Ｂとが重なっている。第三方向Ｄ３から見て、第３のビア導体群４５Ｃが位置する第３領域６４Ｃは、第１領域６４Ａおよび第２領域６４Ｂを挟むようにして第１領域６４Ａおよび第２領域６４Ｂと隣り合っており、第１領域６４Ａおよび第２領域６４Ｂのいずれとも重畳していない。 FIG. 8 shows the positional relationship of three via conductor groups 45A, 45B, and 45C when viewed from the third direction D3. As shown in FIG. 8, when viewed from the third direction D3, all the plurality of via conductors 44 in the connection region 64 are arranged in a lattice arrangement by the three via conductor groups 45A, 45B, and 45C. When viewed from the third direction D3, the first region 64A where the first via conductor group 45A is located and the second region 64B where the second via conductor group 45B is located partially overlap. More specifically, the first region 64A and the second region 64B overlap with each other in a state shifted in the first direction D1 and the second direction D2 by a half interval (half pitch) of the via conductors 45 arranged at equal intervals. . When viewed from the third direction D3, the third region 64C in which the third via conductor group 45C is located is adjacent to the first region 64A and the second region 64B with the first region 64A and the second region 64B interposed therebetween. , does not overlap with either the first region 64A or the second region 64B.

複数のビア導体４５のうち、第１のビア導体群４５Ａは圧電体層１６ａ、１７ｃ、１７ｇをそれぞれ貫通するように設けられており、第２のビア導体群４５Ｂは圧電体層１７ａ、１７ｅをそれぞれ貫通するように設けられており、第３のビア導体群４５Ｃは圧電体層１７ｂ、１７ｄ、１７ｆ、１７ｈをそれぞれ貫通するように設けられている。特に、圧電体層１７ａ～１７ｈでは、素体１１の主面１１ａ側から順に、第２のビア導体群４５Ｂ、第３のビア導体群４５Ｃ、第１のビア導体群４５Ａ、第３のビア導体群４５Ｃ、第２のビア導体群４５Ｂ、第３のビア導体群４５Ｃ、第１のビア導体群４５Ａ、第３のビア導体群４５Ｃの順に並んでいる。換言すると、複数のビア導体４５は、第三方向Ｄ３において、第２のビア導体群４５Ｂと第１のビア導体群４５Ａとが、第３のビア導体群４５Ｃを介して交互に並んでいる。 Among the plurality of via conductors 45, a first via conductor group 45A is provided to penetrate piezoelectric layers 16a, 17c, and 17g, respectively, and a second via conductor group 45B is provided to penetrate piezoelectric layers 17a and 17e. The third via conductor group 45C is provided so as to penetrate through each of the piezoelectric layers 17b, 17d, 17f, and 17h. In particular, in the piezoelectric layers 17a to 17h, in order from the main surface 11a side of the element body 11, the second via conductor group 45B, the third via conductor group 45C, the first via conductor group 45A, and the third via conductor group Group 45C, second via conductor group 45B, third via conductor group 45C, first via conductor group 45A, and third via conductor group 45C are arranged in this order. In other words, in the plurality of via conductors 45, second via conductor groups 45B and first via conductor groups 45A are arranged alternately with third via conductor groups 45C in between.

ここで、ビア導体４２、４３、４４を、圧電体層となるセラミックグリーンシートに形成された貫通孔に導電性ペーストを充填して焼結することにより形成する場合、ビア導体４２、４３、４４の成形が難しく、重畳するようにビア導体を設けた場合にはうまく接続できないことがあり得る。そこで、第三方向Ｄ３において隣り合うビア導体４２、４３、４４同士を、意図的に重畳させないことで接続信頼性の向上が図られている。また、各ビア導体４２、４３、４４の周辺に隆起が生じ得、ビア導体４２、４３、４４が形成された領域６２Ａ～６２Ｃ、６３Ａ～６３Ｃ、６４Ａ～６４Ｃが全体的に隆起し得る。このような隆起が生じた場合に、内部導体層２１～２９間における十分な接続信頼性を維持することが求められる。特に、本実施形態のように、第三方向Ｄ３から見て第１領域６２Ａ、６３Ａ、６４Ａと第２領域６２Ｂ、６３Ｂ、６４Ｂとが重畳する場合には、重畳領域の厚さが局所的に厚くなるため、高い接続信頼性が求められる。 Here, when the via conductors 42, 43, 44 are formed by filling and sintering a conductive paste into through holes formed in a ceramic green sheet serving as a piezoelectric layer, the via conductors 42, 43, 44 It is difficult to mold the via conductors, and if via conductors are provided so as to overlap, it may not be possible to connect them well. Therefore, the connection reliability is improved by intentionally not overlapping the adjacent via conductors 42, 43, and 44 in the third direction D3. In addition, protrusions may occur around each of the via conductors 42, 43, and 44, and the regions 62A to 62C, 63A to 63C, and 64A to 64C in which the via conductors 42, 43, and 44 are formed may be entirely protruded. When such protrusions occur, it is required to maintain sufficient connection reliability between the internal conductor layers 21 to 29. In particular, as in the present embodiment, when the first regions 62A, 63A, 64A and the second regions 62B, 63B, 64B overlap when viewed from the third direction D3, the thickness of the overlapping region locally increases. Due to the increased thickness, high connection reliability is required.

上述した圧電素子１０においては、第三方向Ｄ３から見て、第３領域６２Ｃ、６３Ｃ、６４Ｃが、第１領域６２Ａ、６３Ａ、６４Ａおよび第２領域６２Ｂ、６３Ｂ、６４Ｂと隣り合っており、第１領域６２Ａ、６３Ａ、６４Ａおよび第２領域６２Ｂ、６３Ｂ、６４Ｂのいずれとも重畳していない。加えて、第三方向Ｄ３において、第１のビア導体群４３Ａ、４４Ａ、４５Ａ、第２のビア導体群４３Ｂ、４４Ｂ、４５Ｂおよび第３のビア導体群４３Ｃ、４４Ｃ、４５Ｃのうちの同じビア導体群同士は隣り合っておらず、異なるビア導体群同士が隣り合っている。したがって、圧電素子１０では、第３領域６２Ｃ、６３Ｃ、６４Ｃにより上記隆起が平らに近づくように均されており、すなわち、局所的に厚くなる領域が生じにくくなっており、それにより高い接続信頼性が実現されている。 In the piezoelectric element 10 described above, when viewed from the third direction D3, the third regions 62C, 63C, and 64C are adjacent to the first regions 62A, 63A, and 64A, and the second regions 62B, 63B, and 64B; It does not overlap with any of the first areas 62A, 63A, 64A and the second areas 62B, 63B, 64B. In addition, in the third direction D3, the same via conductors among the first via conductor groups 43A, 44A, 45A, the second via conductor groups 43B, 44B, 45B, and the third via conductor groups 43C, 44C, 45C Groups are not adjacent to each other, but different via conductor groups are adjacent to each other. Therefore, in the piezoelectric element 10, the third regions 62C, 63C, and 64C smooth out the above-mentioned protuberances so that they are almost flat, that is, locally thickened regions are less likely to occur, thereby achieving high connection reliability. has been realized.

圧電素子１０では、複数のビア導体４３、４４、４５は、第三方向Ｄ３において、第２のビア導体群４３Ｂ、４４Ｂ、４５Ｂと第１のビア導体群４３Ａ、４４Ａ、４５Ａとが、第３のビア導体群４３Ｃ、４４Ｃ、４５Ｃを介して交互に並んでいるため、第３領域６２Ｃ、６３Ｃ、６４Ｃにより十分に均されており、接続信頼性のさらなる向上が図られている。なお、第三方向Ｄ３における第１のビア導体群４３Ａ、４４Ａ、４５Ａ、第２のビア導体群４３Ｂ、４４Ｂ、４５Ｂおよび第３のビア導体群４３Ｃ、４４Ｃ、４５Ｃの並び順は、適宜変更することができる。 In the piezoelectric element 10, the plurality of via conductors 43, 44, 45 are arranged such that the second via conductor groups 43B, 44B, 45B and the first via conductor groups 43A, 44A, 45A are arranged in the third direction D3. Since the via conductor groups 43C, 44C, and 45C are arranged alternately, the third regions 62C, 63C, and 64C are sufficiently leveled, and connection reliability is further improved. Note that the arrangement order of the first via conductor groups 43A, 44A, 45A, the second via conductor groups 43B, 44B, 45B, and the third via conductor groups 43C, 44C, 45C in the third direction D3 may be changed as appropriate. be able to.

圧電素子１０の各接続領域６２、６３、６４では、圧電体層１６ａ、１６ｂ、１７ａ、１７ｈの層間すべてに内部導体層２１～２９が存在している。換言すると、各接続領域６２、６３、６４では、圧電体層１６ａ、１６ｂ、１７ａ、１７ｈの１層厚さ分だけ離間して、内部導体層２１～２９が並んでいる。一方、圧電素子１０の駆動領域５０では、圧電体層１６ａ、１６ｂ、１７ａ、１７ｈの層間すべてには内部導体層２１～２９は存在しておらず、圧電体層１６ａ、１６ｂ、１７ａ、１７ｈの２層厚さ分だけ離間して、一部の内部導体層２１、２３、２５、２７、２９が並んでいる。すなわち、駆動領域５０では、内部導体層２１、２３の間に第１の圧電体層対１８Ａが介在し、内部導体層２３、２５の間に第２の圧電体層対１８Ｂが介在し、内部導体層２５、２７の間に第３の圧電体層対１８Ｃが介在し、内部導体層２７、２９の間に第４の圧電体層対１８Ｄが介在している。 In each of the connection regions 62, 63, and 64 of the piezoelectric element 10, internal conductor layers 21 to 29 are present between all the piezoelectric layers 16a, 16b, 17a, and 17h. In other words, in each of the connection regions 62, 63, and 64, the internal conductor layers 21 to 29 are lined up with a distance corresponding to one layer thickness of the piezoelectric layers 16a, 16b, 17a, and 17h. On the other hand, in the driving region 50 of the piezoelectric element 10, the internal conductor layers 21 to 29 are not present between the piezoelectric layers 16a, 16b, 17a, and 17h, and Some of the internal conductor layers 21, 23, 25, 27, and 29 are lined up with a distance of two layer thicknesses. That is, in the drive region 50, the first piezoelectric layer pair 18A is interposed between the inner conductor layers 21 and 23, the second piezoelectric layer pair 18B is interposed between the inner conductor layers 23 and 25, and the inner A third piezoelectric layer pair 18C is interposed between the conductor layers 25 and 27, and a fourth piezoelectric layer pair 18D is interposed between the inner conductor layers 27 and 29.

そのため、図９に示すように、内部導体層２１～２９の第三方向Ｄ３に関する間隔は、駆動領域５０における間隔Ｄが、各接続領域６２、６３、６４における間隔ｄより広くなっている。本実施形態では、駆動領域５０における間隔Ｄは、各接続領域６２、６３、６４における間隔ｄのおよそ２倍になっている。このように駆動領域５０における内部導体層２１、２３、２５、２７、２９の間隔Ｄが相対的に広い場合、圧電素子１０の低容量化が図られるため、圧電素子１０に高電圧を印加したときであっても短絡や発熱等の不具合が生じにくい。 Therefore, as shown in FIG. 9, regarding the intervals in the third direction D3 between the internal conductor layers 21 to 29, the interval D in the drive region 50 is wider than the interval d in each of the connection regions 62, 63, and 64. In this embodiment, the distance D in the drive region 50 is approximately twice the distance d in each of the connection regions 62, 63, and 64. In this way, when the distance D between the internal conductor layers 21, 23, 25, 27, and 29 in the drive region 50 is relatively wide, the capacitance of the piezoelectric element 10 can be reduced, so that a high voltage can be applied to the piezoelectric element 10. Problems such as short circuits and heat generation are less likely to occur even at times.

ただし、単に内部導体層の間隔を広げた場合には、接続領域における内部導体層の間隔も広くなり、それによりビア導体を介した層間接続の接続信頼性が低下する虞がある。そこで本実施形態に係る圧電素子１０では、接続領域６２、６３、６４の間隔ｄに関しては、内部導体層２１、２３、２５、２７、２９のそれぞれの間に内部導体層２２、２４、２６、２８を介在させることで駆動領域５０の間隔Ｄよりも狭めており、それによりビア導体を介した内部導体層間の接続信頼性が高められている。 However, if the interval between the internal conductor layers is simply widened, the interval between the internal conductor layers in the connection region also becomes wider, which may reduce the connection reliability of the interlayer connection via the via conductor. Therefore, in the piezoelectric element 10 according to the present embodiment, regarding the distance d between the connection regions 62, 63, and 64, the inner conductor layers 22, 24, 26, 28, the distance is narrower than the distance D between the drive regions 50, thereby increasing the reliability of the connection between the internal conductor layers via the via conductor.

また、圧電素子１０においては、第三方向Ｄ３に関して、素体１１の主面１１ａ、１１ｂが圧電体層１６ａ、１６ｂで構成されており、駆動部３２を含む内部導体層２１、２３、２５、２７、２９が素体１１の主面１１ａ、１１ｂに露出していない。また、各接続領域６２、６３、６４が、駆動領域５０に囲まれており、素体１１のいずれの側面１１ｃ、１１ｃからも露出していない。そのため、圧電素子１０に高電圧を印加したときであっても、素体１１の表面における内部導体層２１～２９の短絡やリークが生じにくくなっており、駆動電圧の向上が図られている。 Furthermore, in the piezoelectric element 10, with respect to the third direction D3, the main surfaces 11a and 11b of the element body 11 are composed of piezoelectric layers 16a and 16b, and the inner conductor layers 21, 23, 25 including the drive section 32, 27 and 29 are not exposed on the main surfaces 11a and 11b of the element body 11. Furthermore, each of the connection regions 62, 63, and 64 is surrounded by the drive region 50 and is not exposed from any of the side surfaces 11c and 11c of the element body 11. Therefore, even when a high voltage is applied to the piezoelectric element 10, short circuits and leaks in the internal conductor layers 21 to 29 on the surface of the element body 11 are less likely to occur, and the drive voltage is improved.

以上、本発明の実施形態について説明してきたが、本発明は必ずしも上述した実施形態に限定されるものではなく、その要旨を逸脱しない範囲で様々な変更が可能である。 Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the embodiments described above, and various changes can be made without departing from the gist thereof.

上記実施形態では、圧電素子１０がバイモルフ型である形態を一例に説明した。しかし、圧電素子１０は、たとえば、ユニモルフ型であってもよいし、その他の態様の圧電素子であってもよい。 In the above embodiment, the piezoelectric element 10 is of a bimorph type. However, the piezoelectric element 10 may be of a unimorph type, for example, or may be a piezoelectric element of other types.

上述の記載から把握されるとおり、本明細書は下記を開示している。
[付記１]
圧電材料で構成された素体と、該素体内に設けられるとともに第１の方向において積層された複数の内部導体層とを備え、
前記第１の方向から見て、前記複数の内部導体層のうちの極性が異なる前記内部導体層の部分同士が重なる駆動領域と、前記複数の内部導体層のうちの極性が同じ前記内部導体層の部分同士が重なるとともに前記第１の方向に沿って延びる複数のビア導体を介して接続されている複数の接続領域とを含み、
前記複数のビア導体の前記第１の方向において隣り合う同士は前記第１の方向から見て重畳しておらず、前記複数のビア導体が、前記接続領域内に収まる第１領域内に位置する第１のビア導体群と、前記第１のビア導体群とは異なる層内に位置するとともに前記接続領域内に収まる第２領域内に位置する第２のビア導体群と、前記第１のビア導体群および前記第２のビア導体群とは異なる層内に位置するとともに前記接続領域内に収まる第３領域内に位置する第３のビア導体群とを含み、
前記第１の方向から見て、前記第１領域と前記第２領域とは少なくとも一部が重畳し、かつ、前記第３領域は前記第１領域および前記第２領域と隣り合っており、
前記第１の方向において、前記第１のビア導体群、前記第２のビア導体群および前記第３のビア導体群のうちの異なるビア導体群同士が隣り合っている、圧電素子。
[付記２]
前記第１の方向において、前記第１のビア導体群と前記第２のビア導体群とが、前記第３のビア導体群を介して交互に並んでいる、付記１に記載の圧電素子。
[付記３]
前記第１の方向から見て、前記第３のビア導体群が位置する前記第３領域が複数に分かれている、付記１または２に記載の圧電素子。
[付記４]
前記第１の方向から見て、前記複数の第３領域が、前記第１領域および前記第２領域を挟んでいる、付記３に記載の圧電素子。
[付記５]
前記第１の方向から見て、前記各接続領域内の前記複数のビア導体すべてが格子の交点に位置している、付記１～４のいずれか一項に記載の圧電素子。 As understood from the above description, this specification discloses the following.
[Appendix 1]
comprising an element body made of a piezoelectric material, and a plurality of internal conductor layers provided within the element body and laminated in a first direction,
When viewed from the first direction, a driving region where portions of the internal conductor layers having different polarities among the plurality of internal conductor layers overlap, and the internal conductor layer having the same polarity among the plurality of internal conductor layers. a plurality of connection regions in which portions of the conductor overlap each other and are connected via a plurality of via conductors extending along the first direction;
The plurality of via conductors that are adjacent to each other in the first direction do not overlap when viewed from the first direction, and the plurality of via conductors are located in a first region that falls within the connection region. a first via conductor group; a second via conductor group located in a second region that is located in a different layer from the first via conductor group and that falls within the connection region; a third via conductor group located in a layer different from the conductor group and the second via conductor group and located in a third region within the connection region;
When viewed from the first direction, the first region and the second region at least partially overlap, and the third region is adjacent to the first region and the second region,
A piezoelectric element, wherein different via conductor groups among the first via conductor group, the second via conductor group, and the third via conductor group are adjacent to each other in the first direction.
[Additional note 2]
The piezoelectric element according to appendix 1, wherein in the first direction, the first via conductor group and the second via conductor group are arranged alternately with the third via conductor group interposed therebetween.
[Appendix 3]
The piezoelectric element according to appendix 1 or 2, wherein the third region where the third via conductor group is located is divided into a plurality of regions when viewed from the first direction.
[Appendix 4]
The piezoelectric element according to appendix 3, wherein the plurality of third regions sandwich the first region and the second region when viewed from the first direction.
[Appendix 5]
5. The piezoelectric element according to any one of appendices 1 to 4, wherein all of the plurality of via conductors in each of the connection regions are located at intersections of a lattice when viewed from the first direction.

１０…圧電素子、１１…素体、１３、１４、１５…外部電極、１６ａ、１６ｂ、１７ａ～１７ｈ…圧電体層、２１～２９…内部導体層、３２…駆動部、３３、３４…接続部、４３～４５…ビア導体、４３Ａ、４４Ａ、４５Ａ…第１のビア導体群、４３Ｂ、４４Ｂ、４５Ｂ…第２のビア導体群、４３Ｃ、４４Ｃ、４５Ｃ…第３のビア導体群、６２、６３、６４…接続領域、６２Ａ、６３Ａ、６４Ａ…第１領域、６２Ｂ、６３Ｂ、６４Ｂ…第２領域、６２Ｃ、６３Ｃ、６４Ｃ…第３領域。

 DESCRIPTION OF SYMBOLS 10... Piezoelectric element, 11... Element body, 13, 14, 15... External electrode, 16a, 16b, 17a-17h... Piezoelectric layer, 21-29... Internal conductor layer, 32... Drive part, 33, 34... Connection part , 43-45... Via conductor, 43A, 44A, 45A... First via conductor group, 43B, 44B, 45B... Second via conductor group, 43C, 44C, 45C... Third via conductor group, 62, 63 , 64... connection area, 62A, 63A, 64A... first area, 62B, 63B, 64B... second area, 62C, 63C, 64C... third area.

Claims (5)

圧電材料で構成された素体と、該素体内に設けられるとともに第１の方向において積層された複数の内部導体層とを備え、
前記第１の方向から見て、前記複数の内部導体層のうちの極性が異なる前記内部導体層の部分同士が重なる駆動領域と、前記複数の内部導体層のうちの極性が同じ前記内部導体層の部分同士が重なるとともに前記第１の方向に沿って延びる複数のビア導体を介して接続されている複数の接続領域とを含み、
前記複数のビア導体の前記第１の方向において隣り合う同士は前記第１の方向から見て重畳しておらず、前記複数のビア導体が、前記接続領域内に収まる第１領域内に位置する第１のビア導体群と、前記第１のビア導体群とは異なる層内に位置するとともに前記接続領域内に収まる第２領域内に位置する第２のビア導体群と、前記第１のビア導体群および前記第２のビア導体群とは異なる層内に位置するとともに前記接続領域内に収まる第３領域内に位置する第３のビア導体群とを含み、
前記第１の方向から見て、前記第１領域と前記第２領域とは少なくとも一部が重畳し、かつ、前記第３領域は前記第１領域および前記第２領域と隣り合っており、
前記第１の方向において、前記第１のビア導体群、前記第２のビア導体群および前記第３のビア導体群のうちの異なるビア導体群同士が隣り合っている、圧電素子。 comprising an element body made of a piezoelectric material, and a plurality of internal conductor layers provided within the element body and laminated in a first direction,
When viewed from the first direction, a driving region where portions of the internal conductor layers having different polarities among the plurality of internal conductor layers overlap, and the internal conductor layer having the same polarity among the plurality of internal conductor layers. a plurality of connection regions in which portions of the conductor overlap each other and are connected via a plurality of via conductors extending along the first direction;
The plurality of via conductors that are adjacent to each other in the first direction do not overlap when viewed from the first direction, and the plurality of via conductors are located in a first region that falls within the connection region. a first via conductor group; a second via conductor group located in a second region that is located in a different layer from the first via conductor group and that falls within the connection region; a third via conductor group located in a layer different from the conductor group and the second via conductor group and located in a third region within the connection region;
When viewed from the first direction, the first region and the second region at least partially overlap, and the third region is adjacent to the first region and the second region,
A piezoelectric element, wherein different via conductor groups among the first via conductor group, the second via conductor group, and the third via conductor group are adjacent to each other in the first direction. 前記第１の方向において、前記第１のビア導体群と前記第２のビア導体群とが、前記第３のビア導体群を介して交互に並んでいる、請求項１に記載の圧電素子。 The piezoelectric element according to claim 1, wherein in the first direction, the first via conductor group and the second via conductor group are arranged alternately with the third via conductor group interposed therebetween. 前記第１の方向から見て、前記第３のビア導体群が位置する前記第３領域が複数に分かれている、請求項１または２に記載の圧電素子。 The piezoelectric element according to claim 1 or 2, wherein the third region where the third via conductor group is located is divided into a plurality of regions when viewed from the first direction. 前記第１の方向から見て、前記複数の第３領域が、前記第１領域および前記第２領域を挟んでいる、請求項３に記載の圧電素子。 The piezoelectric element according to claim 3, wherein the plurality of third regions sandwich the first region and the second region when viewed from the first direction. 前記第１の方向から見て、前記各接続領域内の前記複数のビア導体すべてが格子の交点に位置している、請求項１に記載の圧電素子。

 The piezoelectric element according to claim 1, wherein all of the plurality of via conductors in each of the connection regions are located at intersections of a grid when viewed from the first direction.
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