JP2018176589A

JP2018176589A - Liquid injection head, liquid injection device, and piezoelectric element

Info

Publication number: JP2018176589A
Application number: JP2017081166A
Authority: JP
Inventors: 矢崎　士郎; Shiro Yazaki; 士郎矢崎
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2017-04-17
Filing date: 2017-04-17
Publication date: 2018-11-15

Abstract

PROBLEM TO BE SOLVED: To simplify a configuration related to a piezoelectric element.SOLUTION: A liquid injection head comprises: a vibration part constituting a wall surface of pressure chamber communicating with any of a plurality of nozzles; and a piezoelectric element vibrating the vibration part. The piezoelectric element includes: a first electrode laminated on the vibration part; a first piezoelectric layer laminated on the first electrode; a second electrode laminated on the first piezoelectric layer; a second piezoelectric layer laminated on the second electrode; and a third electrode laminated on the second piezoelectric layer. In a plan view, the first electrode and the third electrode are brought into contact with each other in a region positioned in an arrangement direction of the plurality of nozzles with respect to the pressure chamber in the liquid injection head.SELECTED DRAWING: Figure 4

Description

本発明は、圧電素子の構造に関する。 The present invention relates to the structure of a piezoelectric element.

複数の圧力室の各々の壁面を構成する振動板を圧電素子により振動させることで圧力室内の液体をノズルから噴射する液体噴射ヘッドが従来から提案されている。例えば特許文献１には、第１共通電極と第１圧電体層と個別電極と第２圧電体層と第２共通電極とがこの順番で積層された構造の圧電素子が開示されている。圧電素子は、長尺状に形成された圧力室に平面視で重なる。 2. Related Art A liquid jet head has conventionally been proposed in which a liquid in a pressure chamber is jetted from a nozzle by vibrating a diaphragm that constitutes a wall surface of each of a plurality of pressure chambers with a piezoelectric element. For example, Patent Document 1 discloses a piezoelectric element having a structure in which a first common electrode, a first piezoelectric layer, an individual electrode, a second piezoelectric layer, and a second common electrode are stacked in this order. The piezoelectric element overlaps with the elongated pressure chamber in plan view.

特開２０１３−２５６１３８号公報JP, 2013-256138, A

特許文献１の構成では、第１共通電極および第２共通電極の各々が、圧力室の長手方向に延在し、平面視で圧力室の外側の領域に到達した端部同士が相互に接続される。したがって、第１共通電極および第２共通電極の各々を平面視で圧力室の外側の領域まで延在させる必要があり、結果的に構造が複雑化するという問題がある。以上の事情を考慮して、本発明の好適な態様は、圧電素子に関する構成を簡素化することを目的とする。 In the configuration of Patent Document 1, each of the first common electrode and the second common electrode extends in the longitudinal direction of the pressure chamber, and the ends reaching the region outside the pressure chamber in plan view are mutually connected. Ru. Therefore, it is necessary to extend each of the first common electrode and the second common electrode to a region outside the pressure chamber in plan view, resulting in a problem that the structure is complicated. In consideration of the above circumstances, a preferred aspect of the present invention aims to simplify the configuration relating to a piezoelectric element.

＜態様１＞
以上の課題を解決するために、本発明の好適な態様（態様１）に係る液体噴射ヘッドは、複数のノズルの何れかに連通する圧力室の壁面を構成する振動部と、前記振動部を振動させる圧電素子とを具備する液体噴射ヘッドであって、前記圧電素子は、前記振動部に積層された第１電極と、前記第１電極に積層された第１圧電体層と、前記第１圧電体層に積層された第２電極と、前記第２電極に積層された第２圧電体層と、前記第２圧電体層に積層された第３電極とを含み、平面視で前記圧力室に対して前記複数のノズルの配列方向に位置する領域において前記第１電極と前記第３電極とが相互に接触する。以上の態様では、平面視で（すなわち圧電素子を構成する複数層の積層の方向からみて）圧力室に対して複数のノズルの配列方向に位置する領域において第１電極と第３電極とが相互に接触する。したがって、第１電極および第３電極の各々を外部回路に接続するための引出配線を第１電極および第３電極の各々について個別に形成する必要がない。すなわち、圧電素子に関する構成が簡素化されるという利点がある。
＜態様２＞
態様１の好適例（態様２）において、前記第１電極および前記第３電極の各々は、複数の圧電素子にわたり連続し、前記第１圧電体層および前記第２電極の各々は、前記複数の圧電素子の各々について個別に形成される。以上の態様では、第３電極が複数の圧電素子にわたり連続するから、第１圧電体層および第２圧電体層を湿気から保護するための保護膜を形成する必要がないという利点がある。また、第１電極および第３電極の各々が複数の圧電素子にわたり連続するから、第１電極と第３電極とを簡便な構成で相互に接触させることが可能である。
＜態様３＞
態様１または態様２の好適例（態様３）において、前記第１電極と前記第３電極とは、平面視で前記圧力室の内側および外側の領域において相互に接触する。以上の態様では、平面視で圧力室の内側および外側の双方の領域において第１電極と第３電極とが相互に接触する。したがって、第１電極と第３電極との間に全域にわたり圧電体層が介在する構成と比較して振動部の変位量を確保しながら、振動部の破損の可能性を低減することが可能である。
＜態様４＞
態様１から態様３の何れかの好適例（態様４）において、前記第２電極と前記第３電極とが前記第２圧電体層を挟んで対向する領域は、平面視で前記圧力室の内側に位置する。以上の態様では、第２電極と第３電極とが第２圧電体層を挟んで対向する領域（すなわち第２電極と第３電極との間の電圧に応じて第２圧電体層が変位する能動部）が平面視で圧力室の内側に位置する。したがって、当該領域が圧力室の外側に位置する構成と比較して、圧電素子の変位に対する拘束が低減され、結果的に第２圧電体層の破損（例えば静電破壊に起因した焼損）を抑制することが可能である。
＜態様５＞
態様１から態様４の何れかの好適例（態様５）において、前記圧力室は、平面視で長尺状であり、前記圧力室の長手方向に平行な縦断面内における前記振動部および前記圧電素子の変形における曲率中心が前記振動部からみて前記圧電素子側に位置する範囲内に、前記第３電極の周縁が位置する。圧電体層等の焼結体（セラミック）は、圧縮強度と比較して引張強度が高い。振動部および圧電素子の変形における曲率中心が振動部からみて圧電素子とは反対側に位置する構成では、第２圧電体層に引張応力が作用し易いから、第２圧電体層が引張応力により破損する可能性がある。他方、振動部および圧電素子の変形における曲率中心が振動部からみて圧電素子側に位置する前述の態様では、第２圧電体層に圧縮応力が作用し易い。したがって、引張応力に起因した第２圧電体層の破損を抑制することが可能である。
＜態様６＞
態様１から態様５の何れかの好適例（態様６）において、前記圧力室は、平面視で長尺状であり、前記第２電極は、前記圧力室の長手方向に沿って延在し、前記長手方向における前記第２電極の第１端部は、平面視で前記圧力室の外側に位置し、前記第１端部とは反対側の第２端部は、平面視で前記圧力室の内側に位置する。以上の態様によれば、第１電極および第３電極とは別個の電圧を第２電極の第１端部に印加することが可能である。
＜態様７＞
態様１から態様６の何れかの好適例（態様７）において、前記第１電極の内部と前記第３電極の内部とには、相互に逆方向の残留応力がある。第１電極の内部と第３電極の内部とに同方向の残留応力がある構成では、圧電素子に電圧が印加されていない状態における圧電素子および振動部の変位量が大きい。他方、第１電極の内部と第３電極の内部とに逆方向の残留応力がある前述の態様によれば、圧電素子に電圧が印加されていない状態における圧電素子および振動部の変位が低減されるという利点がある。
＜態様８＞
態様１から態様７の何れかの好適例（態様８）において、前記振動部および前記圧電素子が変形したときの中立面は、前記振動部または前記第１電極の内部に位置する。以上の態様では、振動部および圧電素子の変形時の中立面（圧縮歪および引張歪の何れも発生しない仮想的な面）が振動部または第１電極の内部に位置するから、例えば第２電極と第３電極との間に中立面が存在する構成と比較して、第１電極と第１圧電体層と第２電極とが積層された部分の応力が低減される。したがって、第１電極と第１圧電体層と第２電極とが積層された部分の破損を抑制することが可能である。
＜態様９＞
本発明の好適な態様（態様９）に係る液体噴射装置は、以上に例示した各態様に係る液体噴射ヘッドを具備する。液体噴射装置の好例は、インクを噴射する印刷装置であるが、本発明に係る液体噴射装置の用途は印刷に限定されない。
＜態様１０＞
本発明の好適な態様に係る圧電素子は、第１電極と、前記第１電極に積層された第１圧電体層と、前記第１圧電体層に積層された長尺状の第２電極と、前記第２電極に積層された第２圧電体層と、前記第２圧電体層に積層された第３電極とを含み、平面視で前記第２電極に対して当該第２電極の短手方向に位置する領域において前記第１電極と前記第３電極とが相互に接触する。 <Aspect 1>
In order to solve the above problems, a liquid jet head according to a preferred aspect (aspect 1) of the present invention includes a vibrating portion forming a wall surface of a pressure chamber communicating with any of a plurality of nozzles, and the vibrating portion. A liquid jet head comprising a piezoelectric element to be vibrated, wherein the piezoelectric element includes a first electrode stacked on the vibrating portion, a first piezoelectric layer stacked on the first electrode, and the first piezoelectric layer. The pressure chamber includes a second electrode laminated on a piezoelectric layer, a second piezoelectric layer laminated on the second electrode, and a third electrode laminated on the second piezoelectric layer, and the pressure chamber in a plan view The first electrode and the third electrode contact each other in a region located in the arrangement direction of the plurality of nozzles. In the above aspect, the first electrode and the third electrode are mutually different in a region located in the arrangement direction of the plurality of nozzles with respect to the pressure chamber in plan view (that is, viewed from the direction of lamination of the plurality of layers constituting the piezoelectric element) Contact Therefore, it is not necessary to separately form lead wires for connecting each of the first and third electrodes to the external circuit for each of the first and third electrodes. That is, there is an advantage that the configuration regarding the piezoelectric element is simplified.
<Aspect 2>
In a preferable example (aspect 2) of the aspect 1, each of the first electrode and the third electrode is continuous across a plurality of piezoelectric elements, and each of the first piezoelectric layer and the second electrode is a plurality of the plurality It is formed individually for each of the piezoelectric elements. In the above aspect, since the third electrode is continuous across the plurality of piezoelectric elements, there is an advantage that it is not necessary to form a protective film for protecting the first piezoelectric layer and the second piezoelectric layer from moisture. In addition, since each of the first electrode and the third electrode is continuous across the plurality of piezoelectric elements, the first electrode and the third electrode can be brought into contact with each other with a simple configuration.
<Aspect 3>
In a preferred embodiment (embodiment 3) of the embodiment 1 or the embodiment 2, the first electrode and the third electrode contact each other in a region inside and outside the pressure chamber in plan view. In the above aspect, the first electrode and the third electrode are in contact with each other in both the inner and outer regions of the pressure chamber in plan view. Therefore, the possibility of breakage of the vibrating portion can be reduced while securing the amount of displacement of the vibrating portion as compared with the configuration in which the piezoelectric layer is interposed over the entire region between the first electrode and the third electrode. is there.
<Aspect 4>
In the preferred embodiment (Aspect 4) according to any one of Aspects 1 to 3, the area where the second electrode and the third electrode face each other with the second piezoelectric layer interposed therebetween is the inside of the pressure chamber in plan view. Located in In the above aspect, a region where the second electrode and the third electrode face each other with the second piezoelectric layer interposed therebetween (that is, the second piezoelectric layer is displaced according to the voltage between the second electrode and the third electrode) The active portion is located inside the pressure chamber in plan view. Therefore, compared with the configuration in which the region is located outside the pressure chamber, the restraint on the displacement of the piezoelectric element is reduced, and as a result, the breakage of the second piezoelectric layer (for example, the burnout due to electrostatic breakdown) is suppressed. It is possible.
<Aspect 5>
In the preferable example (Aspect 5) according to any one of Aspects 1 to 4, the pressure chamber is elongated in plan view, and the vibrating portion and the piezoelectric element in a longitudinal cross section parallel to the longitudinal direction of the pressure chamber The peripheral edge of the third electrode is located in a range in which the center of curvature in the deformation of the element is located on the piezoelectric element side with respect to the vibrating portion. Sintered bodies (ceramics) such as piezoelectric layers have high tensile strength compared to compressive strength. In the configuration in which the vibration center and the curvature center in the deformation of the piezoelectric element are located on the opposite side to the piezoelectric element as viewed from the vibration part, tensile stress easily acts on the second piezoelectric layer. It may be damaged. On the other hand, in the above-described aspect in which the center of curvature in the deformation of the vibrating portion and the piezoelectric element is located on the piezoelectric element side as viewed from the vibrating portion, compressive stress tends to act on the second piezoelectric layer. Therefore, it is possible to suppress the breakage of the second piezoelectric layer caused by the tensile stress.
<Aspect 6>
In the preferable example (Aspect 6) according to any one of Aspects 1 to 5, the pressure chamber is elongated in plan view, and the second electrode extends along the longitudinal direction of the pressure chamber, A first end of the second electrode in the longitudinal direction is located outside the pressure chamber in a plan view, and a second end opposite to the first end is a portion of the pressure chamber in a plan view Located inside According to the above aspect, it is possible to apply a voltage different from the first electrode and the third electrode to the first end of the second electrode.
<Aspect 7>
In the preferred embodiment (Aspect 7) according to any one of Aspects 1 to 6, residual stress in opposite directions is present between the inside of the first electrode and the inside of the third electrode. In the configuration in which residual stress in the same direction is present in the inside of the first electrode and the inside of the third electrode, the amount of displacement of the piezoelectric element and the vibrating portion in the state where voltage is not applied to the piezoelectric element is large. On the other hand, according to the above-mentioned aspect in which the residual stress in the opposite direction exists in the inside of the first electrode and the inside of the third electrode, the displacement of the piezoelectric element and the vibrating portion in the state where voltage is not applied to the piezoelectric element is reduced. Has the advantage of
<Aspect 8>
In the preferred embodiment (Aspect 8) according to any one of Aspects 1 to 7, the neutral plane when the vibrating portion and the piezoelectric element are deformed is located inside the vibrating portion or the first electrode. In the above aspect, for example, since the vibrating portion and the neutral plane (virtual surface where neither compressive strain nor tensile strain is generated) at the time of deformation of the piezoelectric element are located inside the vibrating portion or the first electrode, for example The stress in the portion in which the first electrode, the first piezoelectric layer, and the second electrode are stacked is reduced as compared with the configuration in which the neutral plane exists between the electrode and the third electrode. Therefore, it is possible to suppress breakage of a portion in which the first electrode, the first piezoelectric layer, and the second electrode are stacked.
<Aspect 9>
A liquid ejecting apparatus according to a preferable aspect (aspect 9) of the present invention includes the liquid ejecting head according to each aspect exemplified above. A good example of the liquid ejecting apparatus is a printing apparatus that ejects ink, but the application of the liquid ejecting apparatus according to the present invention is not limited to printing.
<Aspect 10>
A piezoelectric element according to a preferred aspect of the present invention includes a first electrode, a first piezoelectric layer stacked on the first electrode, and an elongated second electrode stacked on the first piezoelectric layer. A second piezoelectric layer stacked on the second electrode, and a third electrode stacked on the second piezoelectric layer, and the width of the second electrode with respect to the second electrode in a plan view The first electrode and the third electrode contact each other in a region located in the direction.

第１実施形態に係る液体噴射装置の構成図である。It is a block diagram of the liquid injection device concerning a 1st embodiment. 液体噴射ヘッドの分解斜視図である。FIG. 2 is an exploded perspective view of a liquid jet head. 液体噴射ヘッドの断面図（図２のIII-III線の断面図）である。FIG. 3 is a cross-sectional view of the liquid jet head (a cross-sectional view along line III-III in FIG. 2). 複数の圧電素子の平面図である。It is a top view of a plurality of piezoelectric elements. 図４におけるＶ-Ｖ線の断面図である。FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 4; 図４におけるVI-VI線の断面図である。FIG. 5 is a cross-sectional view taken along the line VI-VI in FIG. 4; 縦断面内における圧電構造体の変形の説明図である。It is explanatory drawing of a deformation | transformation of the piezoelectric structure in a longitudinal cross-section. 圧電素子と封止体との関係を例示する説明図である。It is explanatory drawing which illustrates the relationship between a piezoelectric element and a sealing body. 第２実施形態における複数の圧電素子の断面図である。It is sectional drawing of the some piezoelectric element in 2nd Embodiment. 変形例における第２圧電体層の説明図である。It is explanatory drawing of the 2nd piezoelectric material layer in a modification.

＜第１実施形態＞
図１は、本発明の第１実施形態に係る液体噴射装置１００を例示する構成図である。第１実施形態の液体噴射装置１００は、液体の例示であるインクを媒体（噴射対象）１２に噴射するインクジェット方式の印刷装置である。媒体１２は、典型的には印刷用紙であるが、樹脂フィルムまたは布帛等の任意の材質の印刷対象が媒体１２として利用され得る。図１に例示される通り、液体噴射装置１００には、インクを貯留する液体容器１４が設置される。例えば液体噴射装置１００に着脱可能なカートリッジ、可撓性のフィルムで形成された袋状のインクパック、またはインクを補充可能なインクタンクが液体容器１４として利用される。 First Embodiment
FIG. 1 is a configuration diagram illustrating a liquid ejecting apparatus 100 according to a first embodiment of the present invention. The liquid ejecting apparatus 100 according to the first embodiment is an ink jet printing apparatus that ejects an ink, which is an example of a liquid, onto a medium (target to be ejected) 12. The medium 12 is typically a printing paper, but a print target of any material such as a resin film or fabric may be used as the medium 12. As illustrated in FIG. 1, the liquid ejecting apparatus 100 is provided with a liquid container 14 storing ink. For example, a cartridge removable from the liquid ejecting apparatus 100, a bag-like ink pack formed of a flexible film, or an ink tank capable of refilling ink is used as the liquid container 14.

図１に例示される通り、液体噴射装置１００は、制御ユニット２０と搬送機構２２と移動機構２４と液体噴射ヘッド２６とを具備する。制御ユニット２０は、例えばＣＰＵ（Central Processing Unit）またはＦＰＧＡ（Field Programmable Gate Array）等の処理回路と半導体メモリー等の記憶回路とを含み、液体噴射装置１００の各要素を統括的に制御する。搬送機構２２は、制御ユニット２０による制御のもとで媒体１２をＹ方向に搬送する。 As illustrated in FIG. 1, the liquid ejecting apparatus 100 includes a control unit 20, a transport mechanism 22, a moving mechanism 24, and a liquid ejecting head 26. The control unit 20 includes, for example, a processing circuit such as a central processing unit (CPU) or a field programmable gate array (FPGA) and a storage circuit such as a semiconductor memory, and centrally controls each element of the liquid ejecting apparatus 100. The transport mechanism 22 transports the medium 12 in the Y direction under the control of the control unit 20.

移動機構２４は、制御ユニット２０による制御のもとで液体噴射ヘッド２６をＸ方向に往復させる。Ｘ方向は、媒体１２が搬送されるＹ方向に交差（典型的には直交）する方向である。第１実施形態の移動機構２４は、液体噴射ヘッド２６を収容する略箱型の搬送体２４２（キャリッジ）と、搬送体２４２が固定された搬送ベルト２４４とを具備する。なお、複数の液体噴射ヘッド２６を搬送体２４２に搭載した構成や、液体容器１４を液体噴射ヘッド２６とともに搬送体２４２に搭載した構成も採用され得る。 The moving mechanism 24 reciprocates the liquid jet head 26 in the X direction under the control of the control unit 20. The X direction is a direction intersecting (typically orthogonal) to the Y direction in which the medium 12 is transported. The moving mechanism 24 according to the first embodiment includes a substantially box-shaped transport body 242 (carriage) accommodating the liquid jet head 26 and a transport belt 244 to which the transport body 242 is fixed. A configuration in which the plurality of liquid jet heads 26 are mounted on the transport body 242 or a configuration in which the liquid container 14 is mounted on the transport body 242 together with the liquid jet heads 26 may be adopted.

液体噴射ヘッド２６は、液体容器１４から供給されるインクを制御ユニット２０による制御のもとで複数のノズル（噴射孔）から媒体１２に噴射する。搬送機構２２による媒体１２の搬送と搬送体２４２の反復的な往復とに並行して各液体噴射ヘッド２６が媒体１２にインクを噴射することで、媒体１２の表面に所望の画像が形成される。なお、Ｘ-Ｙ平面（例えば媒体１２の表面に平行な平面）に垂直な方向を以下ではＺ方向と表記する。各液体噴射ヘッド２６によるインクの噴射方向（典型的には鉛直方向）がＺ方向に相当する。 The liquid jet head 26 jets the ink supplied from the liquid container 14 to the medium 12 from a plurality of nozzles (jet holes) under the control of the control unit 20. A desired image is formed on the surface of the medium 12 by the ink jetted onto the medium 12 by each liquid jet head 26 in parallel with the conveyance of the medium 12 by the conveyance mechanism 22 and the repetitive reciprocation of the conveyance body 242. . The direction perpendicular to the XY plane (for example, a plane parallel to the surface of the medium 12) is hereinafter referred to as the Z direction. The jetting direction (typically, the vertical direction) of the ink by each liquid jet head 26 corresponds to the Z direction.

図２は、液体噴射ヘッド２６の分解斜視図であり、図３は、図２におけるIII-III線の断面図（Ｘ-Ｚ平面に平行な断面）である。図２および図３に例示される通り、液体噴射ヘッド２６は、Ｙ方向に長尺な略矩形状の流路基板３２を具備する。流路基板３２のうちＺ方向の負側の面上には、圧力室基板３４と振動板３６と複数の圧電素子３８と筐体部４２と封止体４４とが設置される。他方、流路基板３２のうちＺ方向の正側の面上には、ノズル板４６と吸振体４８とが設置される。液体噴射ヘッド２６の各要素は、概略的には流路基板３２と同様にＹ方向に長尺な板状部材であり、例えば接着剤を利用して相互に接合される。 2 is an exploded perspective view of the liquid jet head 26, and FIG. 3 is a cross-sectional view (a cross section parallel to the XZ plane) taken along line III-III in FIG. As illustrated in FIGS. 2 and 3, the liquid jet head 26 includes a substantially rectangular flow path substrate 32 which is elongated in the Y direction. The pressure chamber substrate 34, the vibration plate 36, the plurality of piezoelectric elements 38, the housing portion 42, and the sealing body 44 are provided on the surface of the flow path substrate 32 on the negative side in the Z direction. On the other hand, the nozzle plate 46 and the vibration absorber 48 are installed on the surface of the flow path substrate 32 on the positive side in the Z direction. The respective elements of the liquid jet head 26 are generally plate-like members elongated in the Y direction, like the flow path substrate 32, and are joined to one another using, for example, an adhesive.

図２に例示される通り、ノズル板４６は、Ｙ方向に配列する複数のノズルＮが形成された板状部材である。各ノズルＮは、インクが通過する貫通孔である。なお、流路基板３２と圧力室基板３４とノズル板４６とは、例えばシリコン（Ｓi）の単結晶基板をエッチング等の半導体製造技術により加工することで形成される。ただし、液体噴射ヘッド２６の各要素の材料や製法は任意である。Ｙ方向は、複数のノズルＮが配列する方向とも換言され得る。 As illustrated in FIG. 2, the nozzle plate 46 is a plate-like member in which a plurality of nozzles N arranged in the Y direction is formed. Each nozzle N is a through hole through which the ink passes. The flow path substrate 32, the pressure chamber substrate 34 and the nozzle plate 46 are formed by processing, for example, a single crystal substrate of silicon (Si) by a semiconductor manufacturing technique such as etching. However, the material and manufacturing method of each element of the liquid jet head 26 are arbitrary. The Y direction may also be referred to as the direction in which the plurality of nozzles N are arranged.

流路基板３２は、インクの流路を形成するための板状部材である。図２および図３に例示される通り、流路基板３２には、開口部３２２と供給流路３２４と連通流路３２６とが形成される。開口部３２２は、複数のノズルＮにわたり連続するように平面視で（すなわちＺ方向からみて）Ｙ方向に沿う長尺状に形成された貫通孔である。他方、供給流路３２４および連通流路３２６は、ノズルＮ毎に個別に形成された貫通孔である。また、図３に例示される通り、流路基板３２のうちＺ方向の正側の表面には、複数の供給流路３２４にわたる中継流路３２８が形成される。中継流路３２８は、開口部３２２と複数の供給流路３２４とを連通させる流路である。 The flow path substrate 32 is a plate-like member for forming an ink flow path. As illustrated in FIGS. 2 and 3, in the flow path substrate 32, an opening 322, a supply flow path 324, and a communication flow path 326 are formed. The opening 322 is a through hole formed in a long shape along the Y direction in plan view (that is, viewed from the Z direction) so as to be continuous across the plurality of nozzles N. On the other hand, the supply flow channel 324 and the communication flow channel 326 are through holes individually formed for each nozzle N. Further, as illustrated in FIG. 3, on the surface of the flow path substrate 32 on the positive side in the Z direction, a relay flow path 328 extending across the plurality of supply flow paths 324 is formed. The relay flow passage 328 is a flow passage that brings the opening 322 into communication with the plurality of supply flow passages 324.

筐体部４２は、例えば樹脂材料の射出成形で製造された構造体であり、流路基板３２のうちＺ方向の負側の表面に固定される。図３に例示される通り、筐体部４２には収容部４２２と導入口４２４とが形成される。収容部４２２は、流路基板３２の開口部３２２に対応した外形の凹部であり、導入口４２４は、収容部４２２に連通する貫通孔である。図３から理解される通り、流路基板３２の開口部３２２と筐体部４２の収容部４２２とを相互に連通させた空間が液体貯留室（リザーバー）Ｒとして機能する。液体容器１４から供給されて導入口４２４を通過したインクが液体貯留室Ｒに貯留される。 The housing portion 42 is a structure manufactured by, for example, injection molding of a resin material, and is fixed to the surface of the flow path substrate 32 on the negative side in the Z direction. As illustrated in FIG. 3, the housing portion 42 is formed with a housing portion 422 and an introduction port 424. The housing portion 422 is a recess having an outer shape corresponding to the opening 322 of the flow path substrate 32, and the introduction port 424 is a through hole communicating with the housing portion 422. As understood from FIG. 3, a space in which the opening 322 of the flow path substrate 32 and the housing portion 422 of the housing 42 communicate with each other functions as a liquid storage chamber (reservoir) R. The ink supplied from the liquid container 14 and having passed through the inlet 424 is stored in the liquid storage chamber R.

吸振体４８は、液体貯留室Ｒ内の圧力変動を吸収するための要素であり、例えば弾性変形が可能な可撓性のシート部材（コンプライアンス基板）を含んで構成される。具体的には、流路基板３２の開口部３２２と中継流路３２８と複数の供給流路３２４とを閉塞して液体貯留室Ｒの底面を構成するように、流路基板３２のうちＺ方向の正側の表面に吸振体４８が設置される。 The vibration absorbing body 48 is an element for absorbing pressure fluctuation in the liquid storage chamber R, and includes, for example, a flexible sheet member (compliance substrate) capable of elastic deformation. Specifically, the Z direction of the flow path substrate 32 is such that the opening 322 of the flow path substrate 32, the relay flow path 328, and the plurality of supply flow paths 324 are closed to form the bottom surface of the liquid storage chamber R. The absorber 48 is placed on the surface of the positive side of the.

図２および図３に例示される通り、圧力室基板３４は、相異なるノズルＮに対応する複数の圧力室Ｃが形成された板状部材である。複数の圧力室Ｃは、Ｙ方向に沿って配列する。各圧力室Ｃ（キャビティ）は、平面視でＸ方向に沿う長尺状の開口部である。Ｘ方向の正側における圧力室Ｃの端部は平面視で流路基板３２の１個の供給流路３２４に重なり、Ｘ方向の負側における圧力室Ｃの端部は平面視で流路基板３２の１個の連通流路３２６に重なる。 As illustrated in FIGS. 2 and 3, the pressure chamber substrate 34 is a plate-like member in which a plurality of pressure chambers C corresponding to different nozzles N are formed. The plurality of pressure chambers C are arranged along the Y direction. Each pressure chamber C (cavity) is an elongated opening along the X direction in plan view. The end of the pressure chamber C on the positive side in the X direction overlaps with one supply flow path 324 of the flow path substrate 32 in plan view, and the end of the pressure chamber C on the negative side in the X direction is the flow path substrate in plan view Overlapping the one 32 communication channels 326.

圧力室基板３４のうち流路基板３２とは反対側の表面には振動板３６（振動部の例示）が設置される。振動板３６は、弾性的に振動可能な板状部材である。図３に例示される通り、第１実施形態の振動板３６は、第１層３６１と第２層３６２との積層で構成される。第２層３６２は、第１層３６１からみて圧力室基板３４とは反対側に位置する。第１層３６１は、酸化シリコン（ＳiＯ_２）等の弾性材料で形成された弾性膜であり、第２層３６２は、酸化ジルコニウム（ＺrＯ_２）等の絶縁材料で形成された絶縁膜である。なお、所定の板厚の板状部材のうち圧力室Ｃに対応する領域について板厚方向の一部を選択的に除去することで、圧力室基板３４と振動板３６の一部または全部とを一体に形成することも可能である。 A diaphragm 36 (exemplary vibration unit) is provided on the surface of the pressure chamber substrate 34 opposite to the flow channel substrate 32. The vibrating plate 36 is a plate-like member that can elastically vibrate. As illustrated in FIG. 3, the diaphragm 36 according to the first embodiment is configured by stacking the first layer 361 and the second layer 362. The second layer 362 is located on the opposite side of the pressure chamber substrate 34 from the first layer 361. The first layer 361 is an elastic film formed of an elastic material such as silicon oxide (SiO ₂ ), and the second layer 362 is an insulating film formed of an insulating material such as zirconium oxide (ZrO ₂ ). The pressure chamber substrate 34 and a part or all of the diaphragm 36 may be formed by selectively removing a part in the thickness direction of the region corresponding to the pressure chamber C among the plate members having a predetermined thickness. It is also possible to form integrally.

図３から理解される通り、流路基板３２と振動板３６とは、各圧力室Ｃの内側で相互に間隔をあけて対向する。圧力室Ｃは、流路基板３２と振動板３６との間に位置し、当該圧力室Ｃ内に充填されたインクに圧力を付与するための空間である。液体貯留室Ｒに貯留されたインクは、中継流路３２８から各供給流路３２４に分岐して複数の圧力室Ｃに並列に供給および充填される。以上の説明から理解される通り、振動板３６は、圧力室Ｃの壁面（具体的には、圧力室Ｃの一面である上面）を構成する。 As understood from FIG. 3, the flow path substrate 32 and the vibration plate 36 face each other at an interval from each other inside each pressure chamber C. The pressure chamber C is located between the flow path substrate 32 and the vibration plate 36, and is a space for applying pressure to the ink filled in the pressure chamber C. The ink stored in the liquid storage chamber R is branched from the relay flow channel 328 to the respective supply flow channels 324 and supplied and filled in parallel to the plurality of pressure chambers C. As understood from the above description, the diaphragm 36 constitutes the wall surface of the pressure chamber C (specifically, the upper surface which is one surface of the pressure chamber C).

図２および図３に例示される通り、振動板３６のうち圧力室Ｃとは反対側の表面（すなわち第２層３６２の表面）には、相異なるノズルＮ（または圧力室Ｃ）に対応する複数の圧電素子３８が設置される。各圧電素子３８は、駆動信号の供給により変形する受動素子であり、平面視でＸ方向に沿う長尺状に形成される。複数の圧電素子３８は、複数の圧力室Ｃに対応するようにＹ方向に配列する。圧電素子３８の変形に連動して振動板３６が振動すると、圧力室Ｃ内の圧力が変動することで、圧力室Ｃに充填されたインクが連通流路３２６とノズルＮとを通過して噴射される。なお、以下の説明では、振動板３６と圧電素子３８とを含む構造体を「圧電構造体」と表記する場合がある。圧電構造体は、圧力室Ｃの内部圧力を変化させるアクチュエーター（圧電デバイス）である。 As illustrated in FIGS. 2 and 3, the surface of the diaphragm 36 opposite to the pressure chamber C (that is, the surface of the second layer 362) corresponds to different nozzles N (or pressure chambers C). A plurality of piezoelectric elements 38 are installed. Each piezoelectric element 38 is a passive element that is deformed by the supply of a drive signal, and is formed in an elongated shape along the X direction in plan view. The plurality of piezoelectric elements 38 are arranged in the Y direction so as to correspond to the plurality of pressure chambers C. When the diaphragm 36 vibrates in conjunction with the deformation of the piezoelectric element 38, the pressure in the pressure chamber C fluctuates, and the ink filled in the pressure chamber C passes through the communication flow path 326 and the nozzle N and is jetted. Be done. In the following description, a structure including the vibration plate 36 and the piezoelectric element 38 may be referred to as a “piezoelectric structure”. The piezoelectric structure is an actuator (piezoelectric device) that changes the internal pressure of the pressure chamber C.

図２および図３の封止体４４は、複数の圧電素子３８を保護するとともに圧力室基板３４および振動板３６の機械的な強度を補強する構造体であり、振動板３６の表面に例えば接着剤で固定される。封止体４４のうち振動板３６との対向面に形成された凹部の内側に複数の圧電素子３８が収容される。 The sealing body 44 of FIGS. 2 and 3 is a structure that protects the plurality of piezoelectric elements 38 and reinforces the mechanical strength of the pressure chamber substrate 34 and the diaphragm 36, and is adhered to the surface of the diaphragm 36, for example. It is fixed by the agent. A plurality of piezoelectric elements 38 are accommodated inside the recess formed on the surface of the sealing body 44 facing the diaphragm 36.

図３に例示される通り、振動板３６の表面（または圧力室基板３４の表面）には、例えば配線基板５０が接合される。配線基板５０は、制御ユニット２０または電源回路（図示略）と液体噴射ヘッド２６とを電気的に接続するための複数の配線（図示略）が形成された実装部品である。例えばＦＰＣ（Flexible Printed Circuit）やＦＦＣ（Flexible Flat Cable）等の可撓性の配線基板５０が好適に採用される。 As illustrated in FIG. 3, for example, the wiring substrate 50 is bonded to the surface of the vibration plate 36 (or the surface of the pressure chamber substrate 34). The wiring substrate 50 is a mounting component on which a plurality of wires (not shown) for electrically connecting the control unit 20 or a power supply circuit (not shown) and the liquid jet head 26 are formed. For example, a flexible wiring substrate 50 such as a flexible printed circuit (FPC) or a flexible flat cable (FFC) is preferably employed.

複数の圧電素子３８の具体的な構成を以下に詳述する。図４は、複数の圧電素子３８の平面図である。なお、図４では、任意の１個の要素の奥側に位置する要素の周縁（本来は手前側の要素に隠れる部位）も便宜的に図示されている。また、図５は、図４におけるＶ-Ｖ線の断面図であり、図６は、図４におけるVI-VI線の断面図である。圧電素子３８の縦断面（すなわち圧電素子３８の長手方向に沿う断面）が図５に相当し、圧電素子３８の横断面（すなわち圧電素子３８の長手方向に垂直な断面）が図６に相当する。 The specific configuration of the plurality of piezoelectric elements 38 will be described in detail below. FIG. 4 is a plan view of the plurality of piezoelectric elements 38. FIG. In FIG. 4, the peripheral edge of the element located on the back side of any one element (the portion that is originally hidden in the element on the front side) is also illustrated for convenience. 5 is a cross-sectional view taken along line V-V in FIG. 4, and FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. The longitudinal section of the piezoelectric element 38 (that is, the section along the longitudinal direction of the piezoelectric element 38) corresponds to FIG. 5, and the transverse section of the piezoelectric element 38 (that is, the section perpendicular to the longitudinal direction of the piezoelectric element 38) corresponds to FIG. .

図４から図６に例示される通り、各圧電素子３８は、第１電極５１と第１圧電体層５２と第２電極５３と第２圧電体層５４と第３電極５５との積層で構成される。Ｚ方向は、圧電素子３８を構成する複数層が積層された方向とも換言され得る。なお、本明細書において「要素Ａが要素Ｂに積層される」という表現は、要素Ａと要素Ｂとが直接的に接触することまでは必ずしも必要ではない。例えば圧電素子３８の積層構造に着目した場合、例えば圧電素子３８として機能する限りにおいて、要素Ａと要素Ｂとの間に他の層が介在してもよい。 As illustrated in FIG. 4 to FIG. 6, each piezoelectric element 38 is formed by laminating the first electrode 51, the first piezoelectric layer 52, the second electrode 53, the second piezoelectric layer 54, and the third electrode 55. Be done. The Z direction may also be referred to as a direction in which a plurality of layers constituting the piezoelectric element 38 are stacked. In the present specification, the expression “element A is laminated to element B” is not necessarily required until element A and element B are in direct contact with each other. For example, in the case of focusing on the laminated structure of the piezoelectric element 38, another layer may be interposed between the element A and the element B as long as it functions as the piezoelectric element 38, for example.

第１電極５１は、振動板３６の表面（具体的には第２層３６２の表面）に形成される。具体的には、第１電極５１は、複数の圧電素子３８（または複数の圧力室Ｃ）にわたり連続するようにＹ方向に沿って帯状に延在する共通電極である。図４および図５に例示される通り、第１電極５１におけるＸ方向の負側の周縁Ｅa1は、圧力室ＣにおけるＸ方向の負側の端部ｃ1からみてＸ方向の負側に位置する。また、第１電極５１におけるＸ方向の正側の周縁Ｅa2は、圧力室ＣにおけるＸ方向の正側の端部ｃ2からみてＸ方向の正側に位置する。すなわち、複数の圧力室Ｃは、第１電極５１が形成された範囲に平面視で内包される。 The first electrode 51 is formed on the surface of the diaphragm 36 (specifically, the surface of the second layer 362). Specifically, the first electrode 51 is a common electrode that extends in a strip along the Y direction so as to be continuous across the plurality of piezoelectric elements 38 (or the plurality of pressure chambers C). As illustrated in FIGS. 4 and 5, the peripheral edge Ea1 on the negative side in the X direction of the first electrode 51 is located on the negative side in the X direction with respect to the end c1 on the negative side in the X direction of the pressure chamber C. Further, the peripheral edge Ea2 on the positive side in the X direction of the first electrode 51 is located on the positive side in the X direction with respect to the end portion c2 on the positive side in the X direction of the pressure chamber C. That is, the plurality of pressure chambers C are included in a plan view in a range in which the first electrode 51 is formed.

第１圧電体層５２は、第１電極５１に積層される。第１圧電体層５２は、圧電素子３８毎（または圧力室Ｃ毎）に個別に形成されて平面視で圧力室Ｃに重なる。すなわち、Ｘ方向に延在する複数の第１圧電体層５２が、相互に間隔をあけてＹ方向に配列する。第１圧電体層５２の材料または製法は任意である。例えば、チタン酸ジルコン酸鉛等の圧電材料の薄膜をスパッタリング等の公知の成膜技術により形成し、フォトリソグラフィ等の公知の加工技術により当該薄膜を選択的に除去することで、第１圧電体層５２を形成することが可能である。 The first piezoelectric layer 52 is stacked on the first electrode 51. The first piezoelectric layer 52 is individually formed for each of the piezoelectric elements 38 (or each of the pressure chambers C), and overlaps the pressure chambers C in a plan view. That is, the plurality of first piezoelectric layers 52 extending in the X direction are arranged in the Y direction at intervals. The material or manufacturing method of the first piezoelectric layer 52 is optional. For example, a thin film of a piezoelectric material such as lead zirconate titanate is formed by a known film forming technique such as sputtering, and the thin film is selectively removed by a known processing technique such as photolithography. Layer 52 can be formed.

図４および図５に例示される通り、第１圧電体層５２におけるＸ方向の負側の端部Ｅb1は、圧力室Ｃの端部ｃ1からみてＸ方向の負側に位置する。また、第１圧電体層５２におけるＸ方向の正側の端部Ｅb2は、圧力室Ｃの端部ｃ2からみてＸ方向の負側に位置する。すなわち、第１圧電体層５２は、平面視したときに、圧力室Ｃの内側に位置する端部Ｅb2から圧力室Ｃの外側（端部Ｅb1）まで到達するようにＸ方向に延在する。 As illustrated in FIG. 4 and FIG. 5, the end Eb1 on the negative side in the X direction of the first piezoelectric layer 52 is located on the negative side in the X direction with respect to the end c1 of the pressure chamber C. Further, the end Eb2 on the positive side in the X direction of the first piezoelectric layer 52 is located on the negative side in the X direction with respect to the end c2 of the pressure chamber C. That is, the first piezoelectric layer 52 extends in the X direction so as to reach from the end Eb2 located inside the pressure chamber C to the outside (end Eb1) of the pressure chamber C in plan view.

第２電極５３は、第１圧電体層５２に積層される。第２電極５３は、圧電素子３８毎（または圧力室Ｃ毎）に個別に形成された個別電極である。第２電極５３は、平面視で圧力室Ｃに重なる。具体的には、Ｘ方向に延在する複数の第２電極５３が、相互に間隔をあけてＹ方向に配列する。第２電極５３の材料または製法は任意である。例えば、白金またはイリジウム等の導電材料の薄膜をスパッタリング等の公知の成膜技術により形成し、フォトリソグラフィ等の公知の加工技術により当該薄膜を選択的に除去することで、第２電極５３を形成することが可能である。 The second electrode 53 is stacked on the first piezoelectric layer 52. The second electrode 53 is an individual electrode individually formed for each piezoelectric element 38 (or each pressure chamber C). The second electrode 53 overlaps the pressure chamber C in plan view. Specifically, the plurality of second electrodes 53 extending in the X direction are arranged in the Y direction at intervals. The material or manufacturing method of the second electrode 53 is optional. For example, the second electrode 53 is formed by forming a thin film of a conductive material such as platinum or iridium by a known film forming technique such as sputtering and selectively removing the thin film by a known processing technique such as photolithography. It is possible.

第２電極５３は、平面視で第１圧電体層５２と略同形状に形成される。具体的には、図４および図５に例示される通り、第２電極５３におけるＸ方向の負側の端部Ｅc1（第１端部の例示）は、圧力室Ｃの端部ｃ1からみてＸ方向の負側（平面視で圧力室Ｃの外側）に位置する。また、第２電極５３におけるＸ方向の正側の端部Ｅc2（第２端部の例示）は、圧力室Ｃの端部ｃ2からみてＸ方向の負側（平面視で圧力室Ｃの内側）に位置する。すなわち、第２電極５３は、平面視したときに、圧力室Ｃの内側に位置する端部Ｅc2から圧力室Ｃの外側（端部Ｅc1）まで到達するようにＸ方向に延在する。 The second electrode 53 is formed in substantially the same shape as the first piezoelectric layer 52 in a plan view. Specifically, as illustrated in FIG. 4 and FIG. 5, the end Ec1 on the negative side in the X direction of the second electrode 53 (exemplified of the first end) is X as viewed from the end c1 of the pressure chamber C. It is located on the negative side of the direction (outside of the pressure chamber C in plan view). Further, the end Ec2 on the positive side in the X direction in the second electrode 53 (exemplary second end) is the negative side in the X direction as viewed from the end c2 of the pressure chamber C (inside of the pressure chamber C in plan view) Located in That is, the second electrode 53 extends in the X direction so as to reach from the end Ec2 located inside the pressure chamber C to the outside (end Ec1) of the pressure chamber C in plan view.

第１圧電体層５２のうち第１電極５１と第２電極５３とで挟まれた部分（以下「能動部」という）６１は、第１電極５１と第２電極５３との間の電圧に応じた圧電歪みを発生させ、これにより振動部３６が変位する。図５に例示される通り、第１実施形態の能動部６１は、平面視でＸ方向に長尺な部分である。具体的には、能動部６１におけるＸ方向の正側の端部は平面視で圧力室Ｃの内側に位置し、能動部６１におけるＸ方向の負側の端部は平面視で圧力室Ｃの外側（端部ｃ1からみてＸ方向の負側）に位置する。 A portion (hereinafter referred to as an “active portion”) 61 of the first piezoelectric layer 52 sandwiched by the first electrode 51 and the second electrode 53 corresponds to a voltage between the first electrode 51 and the second electrode 53. The piezoelectric portion 36 is displaced due to the piezoelectric distortion. As illustrated in FIG. 5, the active portion 61 of the first embodiment is a portion elongated in the X direction in plan view. Specifically, the positive end of the active portion 61 in the X direction is located inside the pressure chamber C in plan view, and the negative end of the active portion 61 in the X direction is the pressure chamber C in plan view. It is located outside (the negative side in the X direction when viewed from the end c1).

第２圧電体層５４は、第２電極５３に積層される。具体的には、第１圧電体層５２と第２電極５３とを被覆するように第２圧電体層５４が形成される。すなわち、図６から理解される通り、第２圧電体層５４は、第１圧電体層５２の側面と第２電極５３の側面および上面とを被覆する。第１実施形態の第２圧電体層５４は、圧電素子３８毎（または圧力室Ｃ毎）に個別に形成されて平面視で圧力室Ｃに重なる。すなわち、Ｘ方向に延在する複数の第２圧電体層５４が、相互に間隔をあけてＹ方向に配列する。第２圧電体層５４の材料または製法は任意である。例えば、チタン酸ジルコン酸鉛等の圧電材料の薄膜をスパッタリング等の公知の成膜技術により形成し、フォトリソグラフィ等の公知の加工技術により当該薄膜を選択的に除去することで、第２圧電体層５４を形成することが可能である。図４および図５に例示される通り、第２圧電体層５４におけるＸ方向の負側の端部Ｅd1は、圧力室Ｃの端部ｃ1からみてＸ方向の負側に位置する。また、第２圧電体層５４におけるＸ方向の正側の端部Ｅd2は、圧力室Ｃの端部ｃ2からみてＸ方向の正側に位置する。 The second piezoelectric layer 54 is stacked on the second electrode 53. Specifically, the second piezoelectric layer 54 is formed to cover the first piezoelectric layer 52 and the second electrode 53. That is, as understood from FIG. 6, the second piezoelectric layer 54 covers the side surface of the first piezoelectric layer 52 and the side surface and the upper surface of the second electrode 53. The second piezoelectric layer 54 of the first embodiment is formed individually for each of the piezoelectric elements 38 (or for each of the pressure chambers C), and overlaps the pressure chambers C in a plan view. That is, the plurality of second piezoelectric layers 54 extending in the X direction are arranged in the Y direction at intervals. The material or manufacturing method of the second piezoelectric layer 54 is optional. For example, a thin film of a piezoelectric material such as lead zirconate titanate is formed by a known film forming technique such as sputtering, and the thin film is selectively removed by a known processing technique such as photolithography. Layer 54 can be formed. As illustrated in FIGS. 4 and 5, the negative end Ed1 of the second piezoelectric layer 54 in the X direction is located on the negative side in the X direction with respect to the end c1 of the pressure chamber C. Further, the end portion Ed2 of the second piezoelectric layer 54 on the positive side in the X direction is located on the positive side in the X direction with respect to the end portion c2 of the pressure chamber C.

第３電極５５は、第２圧電体層５４に積層される。具体的には、第３電極５５は、複数の圧電素子３８（または複数の圧力室Ｃ）にわたり連続するようにＹ方向に沿って帯状に延在する共通電極である。図４および図５に例示される通り、第３電極５５におけるＸ方向の負側の周縁Ｅe1は、圧力室Ｃの端部ｃ1からみてＸ方向の正側に位置する。また、第３電極５５におけるＸ方向の正側の周縁Ｅe2は、圧力室Ｃの端部ｃ2からみてＸ方向の正側に位置する。 The third electrode 55 is stacked on the second piezoelectric layer 54. Specifically, the third electrode 55 is a common electrode that extends in a strip along the Y direction so as to be continuous across the plurality of piezoelectric elements 38 (or the plurality of pressure chambers C). As illustrated in FIGS. 4 and 5, the peripheral edge Ee1 on the negative side in the X direction of the third electrode 55 is located on the positive side in the X direction with respect to the end c1 of the pressure chamber C. The peripheral edge Ee2 on the positive side in the X direction of the third electrode 55 is located on the positive side in the X direction when viewed from the end c2 of the pressure chamber C.

第２圧電体層５４のうち第２電極５３と第３電極５５とで挟まれた部分（以下「能動部」という）６２は、第２電極５３と第３電極５５との間の電圧に応じた圧電歪みを発生させ、これにより変位する。図５に例示される通り、第１実施形態の能動部６２は、平面視でＸ方向に長尺な部分である。具体的には、能動部６２におけるＸ方向の正側の端部とＸ方向の負側の端部との双方が平面視で圧力室Ｃの内側に位置する。すなわち、能動部６２は平面視で圧力室Ｃの内側に位置する。以上の説明から理解される通り、第１実施形態の圧電素子３８は、能動部６１と能動部６２とがＺ方向に積層された構造である。第２電極５３を挟む第１圧電体層５２と第２圧電体層５４とが、第１電極５１と第３電極５５とで包囲された構造とも表現され得る。 A portion (hereinafter referred to as an “active portion”) 62 of the second piezoelectric layer 54 sandwiched between the second electrode 53 and the third electrode 55 corresponds to a voltage between the second electrode 53 and the third electrode 55. Cause piezoelectric distortion, which causes displacement. As illustrated in FIG. 5, the active portion 62 of the first embodiment is a portion elongated in the X direction in plan view. Specifically, both the end on the positive side in the X direction and the end on the negative side in the X direction of the active portion 62 are located inside the pressure chamber C in plan view. That is, the active portion 62 is located inside the pressure chamber C in a plan view. As understood from the above description, the piezoelectric element 38 according to the first embodiment has a structure in which the active portion 61 and the active portion 62 are stacked in the Z direction. It can also be expressed as a structure in which the first piezoelectric layer 52 and the second piezoelectric layer 54 sandwiching the second electrode 53 are surrounded by the first electrode 51 and the third electrode 55.

図４および図６から理解される通り、第１圧電体層５２と第２電極５３と第２圧電体層５４とは、Ｙ方向において圧力室Ｃの範囲内（すなわち横幅の範囲内）に位置する。したがって、Ｙ方向に相互に隣合う２個の圧電素子３８の間隙には、第１圧電体層５２と第２電極５３と第２圧電体層５４とは形成されず、第１電極５１と第３電極５５とが相互に接触する。すなわち、第１実施形態においては、平面視で圧力室ＣからみてＹ方向に位置する領域Ａ（各圧電素子３８の間隙）において第１電極５１と第３電極５５とが相互に接触する。図４および図６に例示される通り、第１電極５１と第３電極５５とは、平面視で圧力室Ｃの内側および外側の双方の領域において相互に接触する。第２電極５３の短手方向（すなわちＹ方向）に着目すると、平面視で第２電極５３に対して当該第２電極５３の短手方向に位置する領域Ａにおいて第１電極５１と第３電極５５とが相互に接触する構成とも換言され得る。 As understood from FIGS. 4 and 6, the first piezoelectric layer 52, the second electrode 53 and the second piezoelectric layer 54 are positioned within the range of the pressure chamber C (that is, within the range of the lateral width) in the Y direction. Do. Therefore, the first piezoelectric layer 52, the second electrode 53, and the second piezoelectric layer 54 are not formed in the gap between the two piezoelectric elements 38 adjacent to each other in the Y direction. The three electrodes 55 contact each other. That is, in the first embodiment, the first electrode 51 and the third electrode 55 contact each other in the area A (the gap between the piezoelectric elements 38) located in the Y direction as viewed from the pressure chamber C in plan view. As illustrated in FIG. 4 and FIG. 6, the first electrode 51 and the third electrode 55 contact each other in a region both inside and outside the pressure chamber C in a plan view. Focusing on the short side direction of the second electrode 53 (that is, the Y direction), the first electrode 51 and the third electrode 51 in the region A located in the short side direction of the second electrode 53 with respect to the second electrode 53 in plan view In other words, it can be said that 55 is in contact with each other.

以上に説明した通り、第１実施形態では、平面視で圧力室Ｃに対してＹ方向（すなわち複数のノズルＮの配列方向）に位置する領域Ａにおいて第１電極５１と第３電極５５とが相互に接触する。したがって、第１電極５１および第３電極５５の各々を配線基板５０の配線に電気的に接続するための配線を第１電極５１および第３電極５５の各々について個別に形成する必要がない。すなわち、圧電素子３８に関する構造が簡素化されるという利点がある。 As described above, in the first embodiment, the first electrode 51 and the third electrode 55 are provided in the area A located in the Y direction (that is, the arrangement direction of the plurality of nozzles N) with respect to the pressure chamber C in plan view. Contact each other. Therefore, it is not necessary to separately form interconnections for electrically connecting each of the first electrode 51 and the third electrode 55 to the interconnection of the wiring substrate 50 for each of the first electrode 51 and the third electrode 55. That is, there is an advantage that the structure regarding the piezoelectric element 38 is simplified.

なお、第３電極５５が圧電素子３８毎に個別に形成された構成（以下「対比例１」という）では、第２圧電体層５４の表面が第３電極５５の間隙から露出する。第２圧電体層５４は湿気（水分）の付着により特性が劣化するから、対比例１では、第２電極５３のうち第３電極５５から露出した部位を被覆する保護膜を形成する必要がある。対比例１とは対照的に、第１実施形態では、第３電極５５が複数の圧電素子３８にわたり連続する。すなわち、第２圧電体層５４が第３電極５５により被覆される。したがって、第１圧電体層５２および第２圧電体層５４を湿気から保護するための保護膜を別途に形成する必要がないという利点がある。また、第１電極５１および第３電極５５の各々が複数の圧電素子３８にわたり連続するから、第１電極５１と第３電極５５とを簡便な構成で相互に接触させることが可能である。 In the configuration in which the third electrode 55 is individually formed for each piezoelectric element 38 (hereinafter referred to as “comparative example 1”), the surface of the second piezoelectric layer 54 is exposed from the gap of the third electrode 55. The characteristic of the second piezoelectric layer 54 is deteriorated due to the adhesion of moisture (water). Therefore, in the first comparative example, it is necessary to form a protective film that covers a portion of the second electrode 53 exposed from the third electrode 55 . In contrast to the first comparative example, in the first embodiment, the third electrode 55 is continuous across the plurality of piezoelectric elements 38. That is, the second piezoelectric layer 54 is covered by the third electrode 55. Therefore, there is an advantage that it is not necessary to separately form a protective film for protecting the first piezoelectric layer 52 and the second piezoelectric layer 54 from moisture. Further, since each of the first electrode 51 and the third electrode 55 is continuous across the plurality of piezoelectric elements 38, the first electrode 51 and the third electrode 55 can be brought into contact with each other with a simple configuration.

第１実施形態では、平面視で圧力室Ｃの内側および外側の双方の領域において第１電極５１と第３電極５５とが相互に接触する。すなわち、相互に隣合う２個の圧力室Ｃの間の領域Ａには第１圧電体層５２や第２圧電体層５４が形成されない。したがって、第１電極５１と第３電極５５との間に全域にわたり圧電体層が介在する構成と比較して振動板３６の変位量を確保し易いという利点がある。 In the first embodiment, the first electrode 51 and the third electrode 55 contact each other in both the inside and the outside of the pressure chamber C in a plan view. That is, the first piezoelectric layer 52 and the second piezoelectric layer 54 are not formed in the region A between the two pressure chambers C adjacent to each other. Therefore, as compared with the configuration in which the piezoelectric layer is interposed over the entire area between the first electrode 51 and the third electrode 55, the displacement amount of the diaphragm 36 can be easily secured.

ところで、圧電素子３８を構成する各層には成膜時の残留応力が存在し得る。残留応力の方向（引張応力／圧縮応力）は、成膜材料の種類に応じて確定する。第１実施形態では、第１電極５１と第３電極５５とで残留応力が相互に逆方向となるように、第１電極５１および第３電極５５の各々の材料が選定されている。具体的には、第１電極５１は、白金（Ｐt）を主成分とする導電材料で形成され、引張応力が内部に残留する。例えば、白金（Ｐt）とチタン（Ｔi）とイリジウム（Ｉr）とを含有する導電材料で第１電極５１は形成される。他方、第３電極５５は、例えばイリジウム（Ｉr）等の導電材料で形成され、圧縮応力が内部に残留する。 Incidentally, residual stress at the time of film formation may exist in each layer constituting the piezoelectric element 38. The direction of the residual stress (tensile stress / compression stress) is determined according to the type of film forming material. In the first embodiment, the materials of the first electrode 51 and the third electrode 55 are selected such that the residual stress in the first electrode 51 and the third electrode 55 are in opposite directions to each other. Specifically, the first electrode 51 is formed of a conductive material containing platinum (Pt) as a main component, and tensile stress remains inside. For example, the first electrode 51 is formed of a conductive material containing platinum (Pt), titanium (Ti) and iridium (Ir). On the other hand, the third electrode 55 is formed of, for example, a conductive material such as iridium (Ir), and compressive stress remains inside.

第１電極５１と第３電極５５とに同方向の残留応力が存在する構成（以下「対比例２」という）では、圧電素子３８に電圧が印加されていない状態における圧電構造体（すなわち圧電素子３８および振動板３６）の変形量が大きいという傾向がある。以上に例示した対比例２とは対照的に、第１実施形態では、第１電極５１と第３電極５５とに逆方向の残留応力が存在する。すなわち、第１電極５１の残留応力と第３電極５５の残留応力とが相殺される。したがって、第１実施形態によれば、圧電素子３８に電圧が印加されていない状態における圧電構造体の変形量（すなわち初期的な変形量）が対比例２と比較して低減される。したがって、電圧を印加したときの圧電構造体の変形量（ひいてはインクの噴射量）を対比例２と比較して確保し易いという利点がある。なお、前述の例示とは反対に、第１電極５１に圧縮応力が残留するとともに第３電極５５に引張応力が残留するように、第１電極５１および第３電極５５の各々の材料を選定することも可能である。 In a configuration in which residual stress in the same direction exists in the first electrode 51 and the third electrode 55 (hereinafter referred to as “comparative example 2”), a piezoelectric structure in a state where no voltage is applied to the piezoelectric element 38 (ie, piezoelectric element There is a tendency that the amount of deformation of 38 and diaphragm 36) is large. In contrast to the comparative example 2 exemplified above, in the first embodiment, residual stress in the reverse direction exists in the first electrode 51 and the third electrode 55. That is, the residual stress of the first electrode 51 and the residual stress of the third electrode 55 are offset. Therefore, according to the first embodiment, the amount of deformation (that is, the amount of initial deformation) of the piezoelectric structure in the state where no voltage is applied to the piezoelectric element 38 is reduced as compared to Comparative Example 2. Therefore, there is an advantage that it is easy to secure the deformation amount of the piezoelectric structure (and the ink ejection amount) when a voltage is applied, as compared with Comparative Example 2. In addition, the material of each of the first electrode 51 and the third electrode 55 is selected so that the compressive stress remains in the first electrode 51 and the tensile stress remains in the third electrode 55 contrary to the example described above. It is also possible.

次に、図７は、圧力室Ｃを圧縮するように圧電構造体８０が変形した状態の模式図である。圧電素子３８の縦断面内（すなわち圧力室Ｃの長手方向に沿う断面内）における圧電構造体８０の概形が図７には図示されている。図７に例示される通り、圧力室Ｃを加圧するように圧電構造体８０が変形した状態における縦断面内の曲率中心の位置に応じて、圧電構造体８０は、Ｘ方向に沿って範囲Ｇ1と範囲Ｇ2とに区画される。範囲Ｇ1は、圧電構造体８０の変形の曲率中心が振動板３６からみて圧電素子３８とは反対側（Ｚ方向の正側）に位置する領域である。他方、範囲Ｇ2は、圧電構造体の変形の曲率中心が振動板３６からみて圧電素子３８側（Ｚ方向の負側）に位置する領域である。図７から理解される通り、圧電構造体８０が圧力室Ｃを圧縮する状態において、圧電構造体８０の変曲点Ｂからみて圧電構造体８０が上に凸の形状となる区間が範囲Ｇ1であり、変曲点Ｂからみて圧電構造体８０が下に凸の形状となる区間が範囲Ｇ2である。第３電極５５の周縁Ｅe1は、範囲Ｇ2内に位置する。 Next, FIG. 7 is a schematic view of a state in which the piezoelectric structure 80 is deformed so as to compress the pressure chamber C. An outline of the piezoelectric structure 80 in the longitudinal cross section of the piezoelectric element 38 (that is, in the cross section along the longitudinal direction of the pressure chamber C) is illustrated in FIG. As illustrated in FIG. 7, the piezoelectric structure 80 extends along the X direction according to the position of the center of curvature in the longitudinal cross section in a state where the piezoelectric structure 80 is deformed so as to pressurize the pressure chamber C. And the range G2. The range G1 is a region in which the center of curvature of deformation of the piezoelectric structure 80 is located on the opposite side (positive side in the Z direction) to the piezoelectric element 38 as viewed from the diaphragm 36. On the other hand, the range G2 is a region in which the center of curvature of deformation of the piezoelectric structure is located on the side of the piezoelectric element 38 (the negative side in the Z direction) when viewed from the diaphragm 36. As understood from FIG. 7, in a state where the piezoelectric structure 80 compresses the pressure chamber C, a section in which the piezoelectric structure 80 has a convex shape as viewed from the inflection point B of the piezoelectric structure 80 is a range G1. There is a range G2 in which a section in which the piezoelectric structure 80 has a convex shape downward from the inflection point B is present. The peripheral edge Ee1 of the third electrode 55 is located within the range G2.

圧電体等の焼結体（セラミック）は、圧縮強度と比較して引張強度が低いという傾向がある。以上の傾向を前提として、第１実施形態との対比のために、第３電極５５の周縁Ｅe1が範囲Ｇ1内に位置する構成（以下「対比例３」という）を想定する。対比例３では、第２圧電体層５４のうち第３電極５５の周縁Ｅe1の近傍に引張応力が作用し易い。したがって、圧電構造体８０の変形時に発生する引張応力により第２圧電体層５４が破損する可能性がある。対比例３とは対照的に、第１実施形態では、縦断面内における圧電構造体８０の曲率中心が振動板３６からみて圧電素子３８側に位置する範囲Ｇ2内に、第３電極５５の周縁Ｅe1が位置するから、第２圧電体層５４には圧縮応力が作用し易い。したがって、圧電構造体８０の変形時における引張応力に起因して第２圧電体層５４が破損する可能性を低減することが可能である。 Sintered bodies (ceramics) such as piezoelectric bodies tend to have lower tensile strength compared to compressive strength. On the premise of the above tendency, a configuration in which the peripheral edge Ee1 of the third electrode 55 is located within the range G1 (hereinafter referred to as “comparative example 3”) is assumed for comparison with the first embodiment. In Comparative Example 3, tensile stress is likely to act on the vicinity of the peripheral edge Ee1 of the third electrode 55 in the second piezoelectric layer 54. Therefore, the second piezoelectric layer 54 may be broken due to the tensile stress generated when the piezoelectric structure 80 is deformed. In contrast to Comparative Example 3, in the first embodiment, the peripheral edge of the third electrode 55 is within the range G2 in which the center of curvature of the piezoelectric structure 80 in the longitudinal cross section is located on the piezoelectric element 38 side as viewed from the diaphragm 36. Since Ee 1 is located, compressive stress is likely to act on the second piezoelectric layer 54. Therefore, it is possible to reduce the possibility that the second piezoelectric layer 54 is broken due to the tensile stress at the time of deformation of the piezoelectric structure 80.

以上に説明した通り、第１実施形態では、第２電極５３と第２圧電体層５４と第３電極５５との積層で構成される能動部６２が平面視で圧力室Ｃの内側（すなわち振動板３６により拘束されない位置）に位置する。いま、第１実施形態との対比のために、能動部６２のうちＸ方向の負側の端部が平面視で圧力室Ｃの外側に位置する構成（以下「対比例４」という）を想定する。すなわち、第３電極５５の周縁Ｅe1が圧力室Ｃの端部ｃ1からみてＸ方向の負側に位置する。対比例４では、能動部６２のうち圧力室Ｃの外側に位置する部分が、振動板３６により拘束された状態で変位しようとするから、第２圧電体層５４の内部に顕著な応力が発生する。したがって、第２圧電体層５４のうち圧力室Ｃの端部ｃ1の近傍の部分（すなわち振動板３６により拘束される部分と拘束されない部分との境界）が破損する可能性がある。対比例４とは対照的に、第１実施形態では、第２電極５３と第２圧電体層５４と第３電極５５との積層で構成される能動部６２が平面視で圧力室Ｃの内側（すなわち振動板３６により拘束されない位置）に位置する。したがって、圧電素子３８の変位に対する拘束が対比例４と比較して低減され、結果的に第２圧電体層５４の破損（例えば静電破壊に起因した焼損）を抑制することが可能である。 As described above, in the first embodiment, the active portion 62 configured by stacking the second electrode 53, the second piezoelectric layer 54, and the third electrode 55 is an inner side of the pressure chamber C in plan view (that is, vibration Position unrestrained by the plate 36). Now, for comparison with the first embodiment, a configuration in which the end on the negative side in the X direction of the active portion 62 is located outside the pressure chamber C in plan view (hereinafter referred to as “comparative example 4”) is assumed. Do. That is, the peripheral edge Ee1 of the third electrode 55 is located on the negative side in the X direction as viewed from the end c1 of the pressure chamber C. In the fourth comparative example, since a portion of the active portion 62 located outside the pressure chamber C tries to be displaced in a state of being restrained by the diaphragm 36, a significant stress is generated inside the second piezoelectric layer 54. Do. Therefore, a portion of the second piezoelectric layer 54 in the vicinity of the end c1 of the pressure chamber C (that is, a boundary between a portion restrained by the diaphragm 36 and a portion not restrained) may be broken. In contrast to Comparative Example 4, in the first embodiment, the active portion 62 configured by the lamination of the second electrode 53, the second piezoelectric layer 54, and the third electrode 55 is an inner side of the pressure chamber C in a plan view. (Ie, a position not restrained by the diaphragm 36). Therefore, the restraint on the displacement of the piezoelectric element 38 is reduced as compared with the comparative example 4, and as a result, it is possible to suppress the breakage of the second piezoelectric layer 54 (for example, the burnout caused by the electrostatic breakdown).

ところで、能動部６２は平面視で圧力室Ｃの内側に位置する一方、能動部６１におけるＸ方向の負側の端部は圧力室Ｃの外側に位置する。したがって、能動部６１のうち当該端部では振動板３６により変位が拘束される。第１実施形態では、振動板３６および圧電素子３８の変形における中立面が、振動板３６（例えば第２層３６２）および第１電極５１の内部に位置する。具体的には、図５に例示される通り、振動板３６における第１層３６１と第２層３６２との境界から第１電極５１の表面までの範囲Ｗ内に中立面が位置する。中立面は、圧縮歪および引張歪の何れも発生しない仮想的な面である。図５から理解される通り、能動部６１は、能動部６２と比較して中立面に近い。したがって、例えば第２電極５３と第３電極５５との間に中立面が存在する構成と比較して能動部６１の内部（特に第１圧電体層５２の内部）に発生する応力が低減される。したがって、能動部６１についてはＸ方向の負側の端部の変形が振動板３６により拘束される構成にも関わらず、振動板３６の拘束に起因した第１圧電体層５２の破損を抑制できるという利点がある。 The active portion 62 is located inside the pressure chamber C in plan view, while the negative end of the active portion 61 in the X direction is located outside the pressure chamber C. Therefore, the displacement is restrained by the diaphragm 36 at the end of the active portion 61. In the first embodiment, the neutral plane in the deformation of the diaphragm 36 and the piezoelectric element 38 is located inside the diaphragm 36 (for example, the second layer 362) and the first electrode 51. Specifically, as illustrated in FIG. 5, the neutral plane is located within a range W from the boundary between the first layer 361 and the second layer 362 in the diaphragm 36 to the surface of the first electrode 51. The neutral plane is a virtual plane that neither generates compressive strain nor tensile strain. As understood from FIG. 5, the active portion 61 is closer to the neutral plane than the active portion 62. Therefore, for example, the stress generated inside the active portion 61 (in particular, the inside of the first piezoelectric layer 52) is reduced as compared with a configuration in which a neutral plane exists between the second electrode 53 and the third electrode 55, for example. Ru. Therefore, in the active portion 61, regardless of the configuration in which the deformation of the negative end in the X direction is restrained by the diaphragm 36, the breakage of the first piezoelectric layer 52 caused by the restraint of the diaphragm 36 can be suppressed. It has the advantage of

図４および図５に例示される通り、振動板３６の面上には複数の接続端子７１と補助配線７２とが形成される。複数の接続端子７１と補助配線７２とは、金（Ａu）等の低抵抗な導電材料を利用して同層から形成される。すなわち、単体の導電層の選択的な除去（パターニング）により複数の接続端子７１と補助配線７２とが一括的に形成される。 As illustrated in FIGS. 4 and 5, a plurality of connection terminals 71 and an auxiliary wiring 72 are formed on the surface of the diaphragm 36. The plurality of connection terminals 71 and the auxiliary wiring 72 are formed from the same layer using a low resistance conductive material such as gold (Au). That is, the plurality of connection terminals 71 and the auxiliary wiring 72 are collectively formed by selective removal (patterning) of a single conductive layer.

複数の接続端子７１の各々は、圧電素子３８毎に形成されて配線基板５０の配線に接続される。任意の１個の圧電素子３８に対応する接続端子７１は、当該圧電素子３８のうち第１圧電体層５２および第２電極５３の端部（Ｅb1，Ｅc1）に重なる。すなわち、接続端子７１は、第２電極５３に電気的に接続される。したがって、配線基板５０から各接続端子７１に供給される駆動信号は第２電極５３に印加される。すなわち、複数の圧電素子３８の各々の第２電極５３に対して個別の駆動信号が並列に供給される。他方、複数の圧電素子３８にわたり連続する第１電極５１および第３電極５５には、駆動信号の電圧の基準となる所定の電圧（以下「基準電圧」という）が共通に供給される。以上に説明した通り、第１実施形態では、第１電極５１および第３電極５５とは別個の電圧（駆動信号）を第２電極５３の端部に印加することが可能である。 Each of the plurality of connection terminals 71 is formed for each piezoelectric element 38 and connected to the wiring of the wiring substrate 50. The connection terminal 71 corresponding to one arbitrary piezoelectric element 38 overlaps the end (Eb1, Ec1) of the first piezoelectric layer 52 and the second electrode 53 of the piezoelectric element 38. That is, the connection terminal 71 is electrically connected to the second electrode 53. Therefore, the drive signal supplied from the wiring board 50 to each connection terminal 71 is applied to the second electrode 53. That is, individual drive signals are supplied in parallel to the second electrodes 53 of the plurality of piezoelectric elements 38. On the other hand, a predetermined voltage (hereinafter referred to as “reference voltage”) serving as a reference of the voltage of the drive signal is commonly supplied to the first electrode 51 and the third electrode 55 continuous across the plurality of piezoelectric elements 38. As described above, in the first embodiment, it is possible to apply a voltage (drive signal) different from the first electrode 51 and the third electrode 55 to the end of the second electrode 53.

図４および図５に例示される通り、補助配線７２は、第３電極５５に積層される。図４に例示される通り、補助配線７２は、第３電極５５の表面と第２圧電体層５４の表面とにわたり形成され、第３電極５５の周縁Ｅe2に沿ってＹ方向に延在する。補助配線７２は、第１電極５１および第３電極５５よりも低抵抗な導電材料で形成されて第３電極５５（さらには第３電極５５）に電気的に接続される。以上の構成によれば、第１電極５１および第３電極５５における基準電圧の電圧降下が低減される。したがって、基準電圧の相違に起因した各ノズルＮの噴射特性（噴射量，噴射速度または噴射方向）の誤差を低減することが可能である。 As illustrated in FIGS. 4 and 5, the auxiliary wiring 72 is stacked on the third electrode 55. As illustrated in FIG. 4, the auxiliary wiring 72 is formed across the surface of the third electrode 55 and the surface of the second piezoelectric layer 54, and extends in the Y direction along the peripheral edge Ee2 of the third electrode 55. The auxiliary wiring 72 is formed of a conductive material having a resistance lower than that of the first electrode 51 and the third electrode 55, and is electrically connected to the third electrode 55 (further, the third electrode 55). According to the above configuration, the voltage drop of the reference voltage at the first electrode 51 and the third electrode 55 is reduced. Therefore, it is possible to reduce an error in the injection characteristic (injection amount, injection speed or injection direction) of each nozzle N caused by the difference in reference voltage.

図８は、圧電素子３８と封止体４４との関係の説明図であり、図５に例示した縦断面に相当する。図８に例示される通り、封止体４４の底面が接続端子７１の表面と第２圧電体層５４の表面とに接触した状態で、振動板３６の表面に封止体４４が接合される。封止体４４の固定には、例えば樹脂材料で形成された接着剤が好適に利用される。 FIG. 8 is an explanatory view of the relationship between the piezoelectric element 38 and the sealing body 44, which corresponds to the vertical cross section illustrated in FIG. As illustrated in FIG. 8, the sealing body 44 is bonded to the surface of the diaphragm 36 in a state in which the bottom surface of the sealing body 44 is in contact with the surface of the connection terminal 71 and the surface of the second piezoelectric layer 54. . For fixing the sealing body 44, for example, an adhesive formed of a resin material is suitably used.

＜第２実施形態＞
本発明の第２実施形態を説明する。なお、以下に例示する各構成において作用または機能が第１実施形態と同様である要素については、第１実施形態の説明で使用した符号を流用して各々の詳細な説明を適宜に省略する。 Second Embodiment
A second embodiment of the present invention will be described. In addition, about the element which an operation | movement or a function is the same as 1st Embodiment in each structure illustrated below, the code | symbol used by description of 1st Embodiment is diverted and detailed description of each is abbreviate | omitted suitably.

図９は、第２実施形態における複数の圧電素子３８の断面図であり、前掲の図４に対応する断面図である。図９に例示される通り、第２実施形態の圧電素子３８は、第１実施形態と同様の要素（第１電極５１，第１圧電体層５２，第２電極５３，第２圧電体層５４，第３電極５５）に加えて第４電極５６を具備する。第４電極５６は、第２圧電体層５４に積層された低抵抗な導電膜であり、圧電素子３８毎（または圧力室Ｃ毎）に個別に形成された個別電極である。具体的には、第２圧電体層５４の上面の全域を覆うように第４電極５６が形成される。第３電極５５は、第２圧電体層５４と第４電極５６とを被覆する。すなわち、第２圧電体層５４と第３電極５５との間に第４電極５６が介在する。 FIG. 9 is a cross-sectional view of a plurality of piezoelectric elements 38 in the second embodiment, and is a cross-sectional view corresponding to FIG. 4 described above. As illustrated in FIG. 9, the piezoelectric element 38 according to the second embodiment has the same elements as the first embodiment (a first electrode 51, a first piezoelectric layer 52, a second electrode 53, and a second piezoelectric layer 54). , And the third electrode 55), the fourth electrode 56 is provided. The fourth electrode 56 is a low-resistance conductive film stacked on the second piezoelectric layer 54, and is an individual electrode formed individually for each of the piezoelectric elements 38 (or each of the pressure chambers C). Specifically, the fourth electrode 56 is formed to cover the entire top surface of the second piezoelectric layer 54. The third electrode 55 covers the second piezoelectric layer 54 and the fourth electrode 56. That is, the fourth electrode 56 is interposed between the second piezoelectric layer 54 and the third electrode 55.

第２圧電体層５４に対するポストアニールの工程では、第２圧電体層５４が酸化する可能性がある。第２実施形態では、第２圧電体層５４の上面を覆う第４電極５６が形成されるから、第４電極５６の形成後に第２圧電体層５４に対するポストアニールを実行することで第２圧電体層５４の酸化を抑制できるという利点がある。第２実施形態においても第１実施形態と同様の効果が実現される。 In the step of post annealing for the second piezoelectric layer 54, the second piezoelectric layer 54 may be oxidized. In the second embodiment, since the fourth electrode 56 covering the upper surface of the second piezoelectric layer 54 is formed, post annealing is performed on the second piezoelectric layer 54 after the fourth electrode 56 is formed. There is an advantage that the oxidation of the body layer 54 can be suppressed. Also in the second embodiment, the same effect as that of the first embodiment is realized.

＜変形例＞
以上に例示した各形態は多様に変形され得る。前述の各形態に適用され得る具体的な変形の態様を以下に例示する。なお、以下の例示から任意に選択された２以上の態様は、相互に矛盾しない範囲で適宜に併合され得る。 <Modification>
Each form illustrated above can be variously deformed. The aspect of the specific deformation | transformation which may be applied to each above-mentioned form is illustrated below. In addition, 2 or more aspects arbitrarily selected from the following illustration may be suitably merged in the mutually consistent range.

（１）前述の各形態では、第２圧電体層５４を圧電素子３８毎に個別に形成した構成を例示したが、図１０に例示される通り、複数の圧電素子３８にわたり連続するように第２圧電体層５４を形成することも可能である。Ｙ方向に延在する帯状の第２圧電体層５４が図１０には例示されている。図１０に例示される通り、第２圧電体層５４のうちＹ方向に隣合う各第１圧電体層５２（または第２電極５３）の間隙には、Ｘ方向に長尺な切欠部（スリット）５４２が形成される。以上の構成によれば、第２圧電体層５４は圧力室Ｃ毎に個別に変形し得る。 (1) In each of the above-described embodiments, the second piezoelectric layer 54 is formed individually for each piezoelectric element 38. However, as illustrated in FIG. 10, the second piezoelectric layer 54 is continuously formed across the plurality of piezoelectric elements 38. It is also possible to form a two piezoelectric layer 54. A strip-like second piezoelectric layer 54 extending in the Y direction is illustrated in FIG. As illustrated in FIG. 10, in the gaps between the first piezoelectric layers 52 (or the second electrodes 53) adjacent to each other in the Y direction in the second piezoelectric layer 54, cut portions (slits) elongated in the X direction. ) 542 is formed. According to the above configuration, the second piezoelectric layer 54 can be deformed individually for each pressure chamber C.

（２）圧力室Ｃまたは圧電素子３８の平面形状は前述の各形態の例示（長方形状）に限定されない。例えば、シリコン（Ｓi）の単結晶基板を圧力室基板３４として利用した構成では、実際には、圧力室Ｃの平面形状に結晶面が反映される。 (2) The planar shape of the pressure chamber C or the piezoelectric element 38 is not limited to the example (rectangular shape) of each of the above-described embodiments. For example, in a configuration in which a single crystal substrate of silicon (Si) is used as the pressure chamber substrate 34, a crystal plane is actually reflected on the planar shape of the pressure chamber C.

（３）前述の各形態では、液体噴射ヘッド２６を搭載した搬送体２４２を往復させるシリアル方式の液体噴射装置１００を例示したが、複数のノズルＮが媒体１２の全幅にわたり分布するライン方式の液体噴射装置にも本発明を適用することが可能である。 (3) In each of the above-described embodiments, the serial type liquid ejecting apparatus 100 for reciprocating the carrier 242 having the liquid ejecting head 26 mounted is illustrated, but a line type liquid in which a plurality of nozzles N are distributed over the entire width of the medium 12 It is possible to apply the present invention to an injector.

（４）前述の各形態で例示した液体噴射装置１００は、印刷に専用される機器のほか、ファクシミリ装置やコピー機等の各種の機器に採用され得る。もっとも、本発明の液体噴射装置の用途は印刷に限定されない。例えば、色材の溶液を噴射する液体噴射装置は、液晶表示装置のカラーフィルターを形成する製造装置として利用される。また、導電材料の溶液を噴射する液体噴射装置は、配線基板の配線や電極を形成する製造装置として利用される。 (4) The liquid ejecting apparatus 100 exemplified in each of the above-described embodiments may be employed not only for equipment dedicated to printing but also for various equipment such as facsimile machines and copying machines. However, the application of the liquid ejecting apparatus of the present invention is not limited to printing. For example, a liquid ejecting apparatus that ejects a color material solution is used as a manufacturing apparatus that forms a color filter of a liquid crystal display device. In addition, a liquid ejecting apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus that forms wiring and electrodes of a wiring board.

１００…液体噴射装置、１２…媒体、１４…液体容器、２０…制御ユニット、２２…搬送機構、２４…移動機構、２６…液体噴射ヘッド、３２……流路基板、３４……圧力室基板、３４２…除去部、３６……振動板、３８……圧電素子、４２……筐体部、４４……封止体、４６……ノズル板、Ｎ……ノズル、４８……吸振体、５０……配線基板、５１…第１電極、５２…第１圧電体層、５３…第２電極、５４…第２圧電体層、５５…第３電極、Ｃ…圧力室、Ｒ…液体貯留室。
100: liquid ejection device, 12: medium, 14: liquid container, 20: control unit, 22: transport mechanism, 24: movement mechanism, 26: liquid ejection head, 32: flow path substrate, 34: pressure chamber substrate, 342: Removal part, 36: Diaphragm, 38: Piezoelectric element, 42: Housing, 44: Sealing body, 46: Nozzle plate, N: Nozzle, 48: Absorber, 50: ... ... wiring board, 51 ... first electrode, 52 ... first piezoelectric layer, 53 ... second electrode, 54 ... second piezoelectric layer, 55 ... third electrode, C ... pressure chamber, R ... liquid storage chamber.

Claims

A vibrating portion constituting a wall surface of a pressure chamber communicating with any of the plurality of nozzles;
A liquid jet head comprising: a piezoelectric element for vibrating the vibration unit, wherein
The piezoelectric element is
A first electrode stacked on the vibrating portion;
A first piezoelectric layer stacked on the first electrode;
A second electrode stacked on the first piezoelectric layer;
A second piezoelectric layer stacked on the second electrode;
And a third electrode stacked on the second piezoelectric layer,
A liquid jet head, wherein the first electrode and the third electrode mutually contact in a region located in a direction in which the plurality of nozzles are arranged with respect to the pressure chamber in plan view.

Each of the first electrode and the third electrode is continuous across a plurality of piezoelectric elements,
The liquid jet head according to claim 1, wherein each of the first piezoelectric layer and the second electrode is formed individually for each of the plurality of piezoelectric elements.

3. The liquid jet head according to claim 1, wherein the first electrode and the third electrode contact each other in regions inside and outside the pressure chamber in a plan view.

The liquid jet head according to any one of claims 1 to 3, wherein a region where the second electrode and the third electrode face each other across the second piezoelectric layer is located inside the pressure chamber in a plan view. .

The pressure chamber is long in plan view,
The peripheral edge of the third electrode is located in a range where the center of curvature in the deformation of the vibrating portion and the piezoelectric element in the longitudinal cross section along the longitudinal direction of the pressure chamber is located on the piezoelectric element side as viewed from the vibrating portion The liquid jet head according to any one of claims 1 to 4.

The pressure chamber is long in plan view,
The second electrode extends along the longitudinal direction of the pressure chamber, and the first end of the second electrode in the longitudinal direction is located outside the pressure chamber in plan view, and the first end The liquid jet head according to any one of claims 1 to 5, wherein a second end opposite to the portion is located inside the pressure chamber in plan view.

The liquid jet head according to any one of claims 1 to 6, wherein residual stress in opposite directions is present in the inside of the first electrode and the inside of the third electrode.

The liquid jet head according to any one of claims 1 to 7, wherein a neutral plane when the vibration unit and the piezoelectric element are deformed is located inside the vibration unit or the first electrode.

A liquid ejecting apparatus comprising the liquid ejecting head according to any one of claims 1 to 8.

A first electrode,
A first piezoelectric layer stacked on the first electrode;
A long second electrode stacked on the first piezoelectric layer;
A second piezoelectric layer stacked on the second electrode;
And a third electrode stacked on the second piezoelectric layer,
A piezoelectric element in which the first electrode and the third electrode are in contact with each other in a region located in a short direction of the second electrode with respect to the second electrode in plan view.