Liquid jet head and liquid jet device, and piezoelectric device

Abstract

To solve the problem that enough insulation properties cannot be obtained among electric wiring and there is a possibility for breakage to occur to a piezoelectric layer due to migration or the like.SOLUTION: In an active region A0 facing a pressure chamber 12, a diaphragm 50, a first electrode 60, a piezoelectric layer 70, and a second electrode 80 are layered from a pressure chamber substrate 10 side in this order. An area outside the active region A0 in a longitudinal direction of the pressure chamber 12 includes: a first area A1 where the piezoelectric layer 70, the second electrode 80, an insulation layer 150, and a first conductive layer 94(91) are layered from the pressure chamber substrate 10 side in this order; and a second area A2 where the piezoelectric layer 70 and the insulation layer 150 are layered from the pressure chamber substrate 10 side in this order and the second electrode 80 and the first conductive layer 94(91) are not layered.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head and a liquid ejection apparatus having a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode, a vibration plate that vibrates when the piezoelectric element is driven, and a pressure chamber substrate that defines a pressure chamber that applies pressure to a liquid by the vibration of the vibration plate, as well as a piezoelectric device having a piezoelectric element and a vibration plate. [Background technology]

[0002] A typical example of a liquid jet head, which is a piezoelectric device, is an ink jet recording head that ejects ink droplets. A known ink jet recording head includes, for example, a pressure chamber substrate in which pressure chambers communicating with nozzles are formed, and a piezoelectric element provided on one side of the pressure chamber substrate via a vibration plate, and ejects ink droplets from the nozzles by displacing the vibration plate with the piezoelectric element and generating a pressure change in the ink in the pressure chambers.

[0003] Also known as a piezoelectric element is one that includes a first electrode formed on a vibration plate, a piezoelectric layer formed on the first electrode from a piezoelectric material having electromechanical conversion properties, and a second electrode provided on the piezoelectric layer (see, for example, Patent Document 1).

[0004] Patent Document 1 discloses a configuration including a plurality of piezoelectric elements arranged in a row. Each piezoelectric element has an active portion (also called an active part) in which the piezoelectric layer is sandwiched between a first electrode, which is an individual electrode, and a second electrode, which is a common electrode, and the end of the active portion is defined by the end of the second electrode in a direction perpendicular to the direction in which the piezoelectric elements are arranged.

[0005] In this configuration in which the edge of the active part of the piezoelectric element is defined by the edge of the second electrode, there is a risk of damage such as burning due to a short circuit caused by migration, etc. Furthermore, if moisture penetrates into the exposed part of the piezoelectric layer, there is a risk of the piezoelectric layer being destroyed in a relatively short time due to hydrolysis.

[0006] To solve this problem, there is a technique in which the vicinity of the end of the active part of the piezoelectric element is protected by an adhesive layer made of adhesive. Specifically, there is a technique in which an exposed portion where the piezoelectric layer is exposed is provided between a first wiring layer, which is wiring connected to the individual electrodes of the piezoelectric element, and a first metal layer, which is wiring connected to the common electrode of the piezoelectric element, and this exposed portion is covered with an adhesive layer made of adhesive (see Patent Document 2).

[0007] With this configuration, the wirings arranged on either side of the exposed portion of the piezoelectric layer are insulated by the adhesive layer, so that damage to the piezoelectric layer due to migration or the like can be suppressed. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-166160 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-85668 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in a configuration in which adhesive is filled into gaps between the wirings corresponding to the exposed portions as described in Patent Document 2, the adhesive may not be sufficiently filled into the gaps between the wirings, leaving air bubbles, etc. In this case, sufficient insulation between the wirings may not be obtained, and there is a risk that damage to the piezoelectric layer due to migration, etc. may not be suppressed.

[0010] It should be noted that this problem is not limited to liquid ejection heads, such as ink jet recording heads, which eject ink, but also exists in other piezoelectric devices. [Means for solving the problem]

[0011] One aspect of the present invention that solves the above problem is a liquid jet head comprising: a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode; a first conductive layer electrically connected to the second electrode; an insulating layer formed of an insulating material; a vibration plate that vibrates when the piezoelectric element is driven; and a pressure chamber substrate that defines a pressure chamber in which pressure is applied to liquid by the vibration of the vibration plate, wherein an active area facing the pressure chamber has the vibration plate, the first electrode, the piezoelectric layer, and the second electrode stacked in this order from the pressure chamber substrate side, and an area outside the active area in the longitudinal direction of the pressure chamber includes a first area in which the piezoelectric layer, the second electrode, the insulating layer, and the first conductive layer are stacked in this order from the pressure chamber substrate side, and a second area in which the piezoelectric layer and the insulating layer are stacked in this order from the pressure chamber substrate side, and in which the second electrode and the first conductive layer are not stacked.

[0012] Another aspect of the present invention is a liquid ejecting apparatus including the liquid ejecting head of the above aspect.

[0013] Another aspect of the present invention is a piezoelectric device comprising: a substrate having a recess; a vibration plate provided on one side of the substrate; a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode; a first conductive layer electrically connected to the second electrode; and an insulating layer formed of an insulating material; in an active area facing the recess, the vibration plate, the first electrode, the piezoelectric layer, and the second electrode are stacked in this order from the substrate side; and in an area outside the active area in the longitudinal direction of the recess, the device comprises: a first area in which the piezoelectric layer, the second electrode, the insulating layer, and the first conductive layer are stacked in this order from the pressure chamber substrate side; and a second area in which the piezoelectric layer and the insulating layer are stacked in this order from the substrate side, and in which the second electrode and the first conductive layer are not stacked. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is an exploded perspective view of the recording head according to the first embodiment. [Figure 2]FIG. 2 is a plan view of the recording head according to the first embodiment. [Figure 3] 1 is a cross-sectional view of a recording head according to a first embodiment. [Figure 4] 1 is a cross-sectional view showing the overall configuration of a piezoelectric element according to a first embodiment. [Figure 5] 1 is a cross-sectional view showing a main part of a piezoelectric element according to a first embodiment. [Figure 6] 1 is a cross-sectional view showing a main part of a piezoelectric element according to a first embodiment. [Figure 7] FIG. 6 is a cross-sectional view showing a main part of a piezoelectric element according to a second embodiment. [Figure 8] FIG. 10 is a cross-sectional view showing a main part of a piezoelectric element according to a third embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing a main part of a piezoelectric element according to another embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing a main part of a piezoelectric element according to another embodiment. [Figure 11] FIG. 1 is a diagram illustrating a schematic configuration of a recording apparatus according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described in detail below based on embodiments. However, the following description is of one aspect of the present invention, and the configuration of the present invention can be modified as desired within the scope of the invention.

[0016] In each figure, X, Y, and Z represent three spatial axes that are orthogonal to one another. In this specification, the directions along these axes are referred to as the X direction, Y direction, and Z direction. In each figure, the direction indicated by the arrow is the positive (+) direction, and the direction opposite the arrow is the negative (-) direction. The Z direction indicates the vertical direction, with the +Z direction pointing vertically downward and the -Z direction pointing vertically upward. Furthermore, the three spatial axes X, Y, and Z, which are not limited to positive and negative directions, will be described as the X axis, Y axis, and Z axis.

[0017] (Embodiment 1) FIG. 1 is an exploded perspective view of an inkjet recording head, which is an example of a liquid jet head according to a first embodiment of the present invention. FIG. 2 is a plan view of the recording head, and FIG. 3 is a diagram illustrating the schematic configuration of the recording head, which is a cross-sectional view corresponding to line AA in FIG. 2. FIG. 4 is a cross-sectional view illustrating the overall configuration of a piezoelectric element. FIG. 5 is a diagram illustrating the layered structure in each region, which is a cross-sectional view enlarging the vicinity of the end of the piezoelectric element in the X-axis direction. FIG. 6 is a diagram illustrating the bonding state of a protective substrate, which is a cross-sectional view enlarging the vicinity of the end of the piezoelectric element in the X-axis direction.

[0018] As shown in Figures 1 to 3, an ink jet recording head (hereinafter simply referred to as a recording head) 1, which is an example of a liquid ejection head of this embodiment, ejects ink droplets in a first direction, the Z axis direction, more specifically, in the +Z direction.

[0019] The ink jet recording head 1 includes a pressure chamber substrate 10 as an example of a substrate. The pressure chamber substrate 10 is made of, for example, a silicon substrate, a glass substrate, an SOI substrate, or any of various ceramic substrates.

[0020] In the pressure chamber substrate 10, pressure chambers 12 as recesses are arranged in two rows in the X-axis direction, which intersects with the Z-axis direction. That is, in the pressure chamber substrate 10, a plurality of pressure chambers 12 constituting each row are provided along the Y-axis direction, which intersects with the X-axis direction.

[0021] The multiple pressure chambers 12 that make up each row are arranged in a straight line along the Y-axis direction so that they are positioned at the same position in the X-axis direction. Pressure chambers 12 adjacent to each other in the Y-axis direction are separated by partitions. Of course, the arrangement of the pressure chambers 12 is not particularly limited. For example, the arrangement of the multiple pressure chambers 12 lined up in the Y-axis direction may be a so-called staggered arrangement, in which every other pressure chamber 12 is positioned offset in the X-axis direction.

[0022] Furthermore, the pressure chamber 12 of this embodiment is formed in a rectangular shape, for example, such that the length in the X-axis direction is longer than the length in the Y-axis direction when viewed in a plan view from the +Z direction. Of course, the shape of the pressure chamber 12 when viewed in a plan view from the +Z direction is not particularly limited, and may be a parallelogram, polygon, circle, oval, or the like. Note that the oval shape referred to here refers to a shape based on a rectangular shape with semicircular ends at both longitudinal ends, and includes a rounded rectangular shape, an elliptical shape, an egg shape, and the like.

[0023] On the +Z direction side of the pressure chamber substrate 10, a communication plate 15, a nozzle plate 20, and a compliance substrate 45 are laminated in this order.

[0024] The communicating plate 15 is provided with nozzle communicating passages 16 that communicate between the pressure chambers 12 and the nozzles 21. The communicating plate 15 is also provided with a first manifold portion 17 and a second manifold portion 18 that constitute part of a manifold 100 that serves as a common liquid chamber through which the multiple pressure chambers 12 communicate. The first manifold portion 17 is provided so as to penetrate the communicating plate 15 in the Z-axis direction. The second manifold portion 18 is provided so as to open on the surface on the +Z direction side, without penetrating the communicating plate 15 in the Z-axis direction.

[0025] Furthermore, the communication plate 15 is provided with supply communication passages 19 that communicate with one end of the pressure chambers 12 in the X-axis direction, independently for each pressure chamber 12. The supply communication passages 19 communicate between the second manifold portion 18 and each pressure chamber 12, and supply ink in the manifold 100 to each pressure chamber 12.

[0026] The communicating plate 15 can be made of a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate, or the like. Examples of metal substrates include a stainless steel substrate. It is preferable that the communicating plate 15 is made of a material with approximately the same thermal expansion coefficient as the pressure chamber substrate 10. This makes it possible to suppress warping of the pressure chamber substrate 10 and the communicating plate 15 due to differences in thermal expansion coefficients when the temperatures of the pressure chamber substrate 10 and the communicating plate 15 change.

[0027] The nozzle plate 20 is provided on the surface of the communication plate 15 opposite to the pressure chamber substrate 10, i.e., on the +Z direction side. Nozzles 21 that communicate with each pressure chamber 12 via nozzle communication paths 16 are formed in the nozzle plate 20.

[0028] In this embodiment, the plurality of nozzles 21 are arranged in a line along the Y-axis direction. The nozzle plate 20 is provided with two nozzle rows in the X-axis direction, each row having the plurality of nozzles 21 arranged therein. That is, the plurality of nozzles 21 in each row are arranged so that they are positioned at the same position in the X-axis direction. The arrangement of the nozzles 21 is not particularly limited. For example, the nozzles 21 arranged in a line in the Y-axis direction may be arranged so that every other nozzle 21 is shifted in the X-axis direction.

[0029] The material of the nozzle plate 20 is not particularly limited, but examples thereof include a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, and a metal substrate. Examples of metal plates include a stainless steel substrate. Furthermore, organic materials such as polyimide resin can also be used as the material of the nozzle plate 20. However, it is preferable to use a material for the nozzle plate 20 that has approximately the same thermal expansion coefficient as the communication plate 15. This makes it possible to suppress warping of the nozzle plate 20 and the communication plate 15 due to differences in thermal expansion coefficients when the temperatures of the nozzle plate 20 and the communication plate 15 change.

[0030] The compliance substrate 45, together with the nozzle plate 20, is provided on the surface of the communication plate 15 opposite to the pressure chamber substrate 10, i.e., on the +Z direction side. This compliance substrate 45 is provided around the nozzle plate 20 and seals the openings of the first manifold section 17 and the second manifold section 18 provided in the communication plate 15. In this embodiment, the compliance substrate 45 includes a sealing film 46 made of a flexible thin film, and a fixed substrate 47 made of a hard material such as metal. The region of the fixed substrate 47 facing the manifold 100 is an opening 48 that is completely removed in the thickness direction. Therefore, one side of the manifold 100 forms a compliance section 49 that is sealed only by the flexible sealing film 46.

[0031] On the other hand, as will be described in detail later, on the side of the pressure chamber substrate 10 opposite the nozzle plate 20 etc., i.e., on the surface on the -Z direction side, there are provided a vibration plate 50 and a piezoelectric element 300 that flexes and deforms the vibration plate 50 to cause a pressure change in the ink inside the pressure chamber 12. Note that Fig. 3 is a diagram for explaining the overall configuration of the recording head 1, and the piezoelectric element 300 is shown in a simplified form.

[0032] A protection substrate 30 having approximately the same size as the pressure chamber substrate 10 is further bonded to the surface of the pressure chamber substrate 10 on the -Z direction side. The protection substrate 30 has holding portions 31 which are spaces that protect the piezoelectric elements 300. The holding portions 31 are provided independently for each row of the piezoelectric elements 300 arranged side by side in the Y axis direction, and two holding portions 31 are formed side by side in the X axis direction. In addition, the protection substrate 30 has a through hole 32 that penetrates in the Z axis direction between the two holding portions 31 arranged side by side in the X axis direction.

[0033] Additionally, a case member 40 is fixed onto the protective substrate 30. The case member 40, which together with the pressure chamber substrate 10 defines a manifold 100 that communicates with the multiple pressure chambers 12, has approximately the same shape as the above-mentioned communicating plate 15 in a plan view seen in the Z-axis direction, and is bonded to the protective substrate 30 as well as to the above-mentioned communicating plate 15.

[0034] Such a case member 40 has an accommodation section 41 on the protective substrate 30 side, which is a space deep enough to accommodate the pressure chamber substrate 10 and the protective substrate 30. This accommodation section 41 has an opening area wider than the surface of the protective substrate 30 that is bonded to the pressure chamber substrate 10. Then, with the pressure chamber substrate 10 and the protective substrate 30 accommodated in the accommodation section 41, the opening surface of the accommodation section 41 on the nozzle plate 20 side is sealed by a communicating plate 15.

[0035] Additionally, third manifold portions 42 are defined in the case member 40 on both outer sides of the accommodation portion 41 in the X-axis direction. The manifold 100 of this embodiment is configured by the first manifold portion 17 and the second manifold portion 18 provided in the communication plate 15, and the third manifold portion 42. The manifold 100 is provided continuously along the Y-axis direction, and the supply communication passages 19 that communicate between each pressure chamber 12 and the manifold 100 are arranged side by side in the Y-axis direction.

[0036] The case member 40 is also provided with an inlet 44 that communicates with the manifolds 100 and supplies ink to each manifold 100. The case member 40 is also provided with a connection port 43 that communicates with the through-hole 32 of the protection substrate 30 and through which the wiring substrate 120 is inserted.

[0037] In the recording head 1 of this embodiment, ink is taken in from an inlet 44 connected to an external ink supply means (not shown), and the interior is filled with ink from the manifold 100 to the nozzles 21. Then, a voltage is applied to each piezoelectric element 300 corresponding to each pressure chamber 12 in accordance with a recording signal from a drive circuit 121. This causes the piezoelectric elements 300 and the diaphragm 50 to bend and deform, increasing the pressure inside each pressure chamber 12 and causing ink droplets to be ejected from each nozzle 21.

[0038] The configuration of the piezoelectric element 300 according to this embodiment will be described below. As described above, the piezoelectric element 300 is provided on the surface of the pressure chamber substrate 10 opposite the nozzle plate 20 via the vibration plate 50. In other words, the recording head 1 comprises the pressure chamber substrate 10, the vibration plate 50 provided on the surface of the pressure chamber substrate 10 on the -Z direction side, and the piezoelectric element 300.

[0039] 4 and 5, the diaphragm 50 is made up of an elastic film 51 made of silicon oxide provided on the pressure chamber substrate 10 side, and an insulating film 52 made of zirconium oxide provided on the elastic film 51. The liquid flow paths of the pressure chambers 12, etc. are formed by anisotropically etching the pressure chamber substrate 10 from the surface on the +Z direction side, and the surface on the -Z direction side of the liquid flow paths of the pressure chambers 12, etc. is closed by the elastic film 51.

[0040] The elastic film 51 can also be formed as a substrate integrated with the pressure chamber substrate 10. More specifically, for example, the pressure chamber substrate 10 can be formed from silicon, and its surface can be thermally oxidized to generate a silicon oxide layer, which can then be used as the elastic film 51.

[0041] Furthermore, there are no particular limitations on the configuration of the diaphragm 50. The diaphragm 50 may be configured, for example, with either an elastic film 51 or an insulating film 52, or may further include other films in addition to the elastic film 51 and the insulating film 52. Examples of materials for the other films include silicon and silicon nitride.

[0042] The piezoelectric element 300 is also called a piezoelectric actuator and is a pressure generating means that generates a pressure change in the ink inside the pressure chamber 12. The piezoelectric element 300 includes a first electrode 60, a piezoelectric layer 70, and a second electrode 80 that are layered in this order from the +Z direction side, which is the vibration plate 50 side, toward the -Z direction side.

[0043] Here, in the piezoelectric element 300, a portion where piezoelectric strain occurs in the piezoelectric layer 70 when a voltage is applied between the first electrode 60 and the second electrode 80 is referred to as an active portion 310. In contrast, a portion where piezoelectric strain does not occur in the piezoelectric layer 70 is referred to as an inactive portion 320. In other words, in the piezoelectric element 300, the portion where the piezoelectric layer 70 is sandwiched between the first electrode 60 and the second electrode 80 is the active portion 310, and the portion where the piezoelectric layer 70 is not sandwiched between the first electrode 60 and the second electrode 80 is the inactive portion 320.

[0044] Furthermore, when the piezoelectric element 300 is driven, the portion that actually displaces in the Z-axis direction is referred to as the flexible portion, and the portion that does not displace in the Z-axis direction is referred to as the non-flexible portion. That is, of the active portion 310 of the piezoelectric element 300, the portion that faces the pressure chamber 12 in the Z-axis direction is the flexible portion, and the portion outside the pressure chamber 12 is the non-flexible portion.

[0045] Generally, one of the electrodes of the active portion 310 is configured as an individual electrode independent for each piezoelectric element 300, and the other electrode is configured as a common electrode common to the plurality of piezoelectric elements 300. In this embodiment, the first electrode 60 configures the individual electrode, and the second electrode 80 configures the common electrode.

[0046] The first electrode 60 is separated for each pressure chamber 12 to form an independent individual electrode for each active section 310. The first electrode 60 is formed with a width narrower than the width of the pressure chamber 12 in the Y-axis direction. In other words, both ends of the first electrode 60 in the Y-axis direction are located inside the region facing the pressure chamber 12.

[0047] 4, the first electrode 60 has an end 60a in the −X direction and an end 60b in the +X direction of the first electrode 60, which are located outside the pressure chamber 12. That is, the end 60a in the −X direction of the first electrode 60 is located at a position closer to the −X direction than the end 12a in the −X direction of the pressure chamber 12, and the end 60b in the +X direction of the first electrode 60 is located at a position closer to the +X direction than the end 12b in the +X direction of the pressure chamber 12.

[0048] The material of the first electrode 60 is not particularly limited, but may be, for example, a conductive material such as a metal such as iridium or platinum, or a conductive metal oxide such as indium tin oxide, abbreviated as ITO.

[0049] The piezoelectric layer 70 has a predetermined length in the X-axis direction and is provided continuously along the Y-axis direction. That is, the piezoelectric layer 70 is provided continuously with a predetermined thickness along the direction in which the pressure chambers 12 are arranged. The thickness of the piezoelectric layer 70 is not particularly limited, but is formed to a thickness of about 1 to 4 μm. The piezoelectric layer 70 does not have to be continuous along the direction in which the pressure chambers 12 are arranged. For example, a notch may be provided in the piezoelectric layer 70 between each pair of pressure chambers 12.

[0050] 4, the end 70a of the piezoelectric layer 70 in the -X direction is located outside the end 60a of the first electrode 60 in the -X direction. In other words, the end 60a of the first electrode 60 is covered by the piezoelectric layer 70. On the other hand, the end 70b of the piezoelectric layer 70 in the +X direction is located inside the end 60b of the first electrode 60 in the +X direction, that is, on the pressure chamber 12 side, and the end 60b of the first electrode 60 is not covered by the piezoelectric layer 70.

[0051] The piezoelectric layer 70 may be a perovskite-structured crystalline film (perovskite-type crystal) formed on the first electrode 60 and made of a ferroelectric ceramic material exhibiting electromechanical transduction. Examples of materials that can be used for the piezoelectric layer 70 include ferroelectric piezoelectric materials such as lead zirconate titanate (PZT), and materials to which metal oxides such as niobium oxide, nickel oxide, or magnesium oxide are added. Specifically, lead titanate (PbTiO), lead zirconate titanate (Pb(Zr,Ti)O), lead zirconate (PbZrO), lead lanthanum titanate ((Pb,La),TiO), lead lanthanum zirconate titanate ((Pb,La)(Zr,Ti)O), or magnesium zirconate titanate (Pb(Zr,Ti)(Mg,Nb)O). In this embodiment, lead zirconate titanate (PZT) is used as the piezoelectric layer 70.

[0052] Furthermore, the material of the piezoelectric layer 70 is not limited to lead-based piezoelectric materials containing lead, but lead-free piezoelectric materials can also be used. Examples of lead-free piezoelectric materials include bismuth ferrite ((BiFeO3), abbreviated as "BFO"), barium titanate ((BaTiO3), abbreviated as "BT"), potassium sodium niobate ((K,Na)(NbO3), abbreviated as "KNN"), potassium sodium lithium niobate ((K,Na,Li)(NbO3)), potassium sodium lithium tantalate niobate ((K,Na,Li)(Nb,Ta)O3), bismuth potassium titanate ((Bi 1 / 2 K 1 / 2 )TiO3, abbreviated as "BKT"), bismuth sodium titanate ((Bi 1 / 2 Na 1 / 2 )TiO3, abbreviated as "BNT"), bismuth manganate (BiMnO3, abbreviated as "BM"), and complex oxides containing bismuth, potassium, titanium, and iron and having a perovskite structure (x[(Bi x K 1-x)TiO3]-(1-x)[BiFeO3], abbreviated as "BKT-BF"), complex oxides containing bismuth, iron, barium and titanium and having a perovskite structure ((1-x)[BiFeO3]-x[BaTiO3], abbreviated as "BFO-BT"), and oxides to which metals such as manganese, cobalt and chromium have been added ((1-x)[Bi(Fe 1-y M y )O3]-x[BaTiO3] (M is Mn, Co, or Cr).

[0053] The second electrode 80 is provided on the −Z direction side of the piezoelectric layer 70, which is opposite to the first electrode 60, and constitutes a common electrode shared by the plurality of piezoelectric elements 300. The second electrode 80 has a predetermined length in the X-axis direction and is provided continuously along the Y-axis direction.

[0054] 4, the −X-direction end 80a of the second electrode 80 is disposed so as to be outside the end 60a of the first electrode 60 covered with the piezoelectric layer 70. That is, the end 80a of the second electrode 80 is located outside the −X-direction end 12a of the pressure chamber 12 and outside the end 60a of the first electrode 60. Therefore, the −X-direction end of the active portion 310, i.e., the boundary between the active portion 310 and the inactive portion 320, is defined by the end 60a of the first electrode 60.

[0055] 4, the +X-direction end 80b of the second electrode 80 is disposed outside the +X-direction end 12b of the pressure chamber 12, but inside the +X-direction end 70b of the piezoelectric layer 70. As described above, the end 70b of the piezoelectric layer 70 is located inside the end 60b of the first electrode 60. Therefore, the end 80b of the second electrode 80 is located on the piezoelectric layer 70 inside the end 60b of the first electrode 60.

[0056] In this way, the end 80b of the second electrode 80 is disposed in the −X direction relative to the +X direction ends 60b, 70b of the piezoelectric layer 70 and the first electrode 60, and therefore the +X direction end of the active portion 310, i.e., the boundary between the active portion 310 and the inactive portion 320, is defined by the end 80b of the second electrode 80. In addition, outside the end 80b of the second electrode 80, there is an exposed portion 71 where the surface of the piezoelectric layer 70 is exposed.

[0057] The material of the second electrode 80 is not particularly limited, but similar to the first electrode 60, conductive materials such as metals such as iridium and platinum, and conductive metal oxides such as indium tin oxide are preferably used.

[0058] Furthermore, outside the end 80b of the second electrode 80, i.e., further in the +X direction from the end 80b of the second electrode 80, a wiring layer 85 is provided which is made of the same layer as the second electrode 80 but is electrically discontinuous with the second electrode 80.

[0059] This wiring layer 85 is formed from on the piezoelectric layer 70 to on the first electrode 60 extending in the +X direction beyond the piezoelectric layer 70, with a gap therebetween so as not to come into contact with the end 80b of the second electrode 80. Furthermore, the wiring layer 85 is provided independently for each active section 310. That is, a plurality of wiring layers 85 are arranged at predetermined intervals in the Y-axis direction.

[0060] In this way, the second electrode 80 and the wiring layer 85 are provided at a distance in the X-axis direction on the piezoelectric layer 70 that constitutes the piezoelectric element 300. The surface of the piezoelectric layer 70 is exposed in the gap between the second electrode 80 and the wiring layer 85. In other words, the portion between the second electrode 80 and the wiring layer 85 of the piezoelectric layer 70 that constitutes the piezoelectric element 300 is an exposed portion 71 where the surface opposite to the pressure chamber substrate 10 is exposed from the second electrode 80 and the wiring layer 85.

[0061] Here, the thickness d1 of the piezoelectric layer 70 at the exposed portion 71 is thinner than the thickness d2 of the other portion of the piezoelectric layer 70 (see FIG. 5). That is, the exposed portion 71 of the piezoelectric layer 70 has a recess 72 formed by thinly removing the surface layer portion.

[0062] The exposed portion 71 of the piezoelectric layer 70 is covered with an insulating layer 150 made of an insulating material. The insulating layer 150 is provided continuously in the X-axis direction from above the second electrode 80 to above the wiring layer 85. That is, the insulating layer 150 is provided so as to cover not only the exposed portion 71 of the piezoelectric layer 70 but also the end portion 80b of the second electrode 80 and the end portion 85a of the wiring layer 85 in the -X direction shown in FIG. 4. In other words, the insulating layer 150 is formed so as to overlap with the end portion 80b of the second electrode 80 and the end portion 85a of the wiring layer 85 in the X-axis direction.

[0063] The insulating layer 150 is provided continuously in the Y-axis direction across an area corresponding to the plurality of piezoelectric elements 300. This facilitates improving the moisture barrier properties. However, the insulating layer 150 only needs to cover at least the portion of the exposed portion 71 of the piezoelectric layer 70 that is sandwiched between the second electrode 80 and the wiring layer 85, and may be provided independently for each piezoelectric element 300.

[0064] The material of the insulating layer 150 is not particularly limited as long as it has electrical insulation and moisture barrier properties, but for example, a photosensitive resin such as polyimide is used. When a photosensitive resin is used, the insulating layer 150 is formed by photolithography after heat treatment following the formation of the second electrode 80. Alternatively, the material of the insulating layer 150 may be an inorganic insulating material such as aluminum oxide. In this case, for example, the insulating layer 150 can be formed over the entire surface by sputtering using a mask, and then lifted off to form the insulating layer 150 only in the desired region.

[0065] A common lead electrode 91, which is a first conductive layer, is connected to the second electrode 80 that constitutes the piezoelectric element 300. An individual lead electrode 92, which is a second conductive layer, is connected to the first electrode 60 that constitutes the piezoelectric element 300. A flexible wiring substrate 120 is connected to the ends of the common lead electrode 91 and the individual lead electrode 92 opposite to the ends connected to the piezoelectric element 300.

[0066] In this embodiment, the common lead electrode 91 and the individual lead electrodes 92 extend so as to be exposed within through holes 32 formed in the protection substrate 30, and are electrically connected to the wiring substrate 120 within these through holes 32. A drive circuit 121 having switching elements for driving the piezoelectric elements 300 is mounted on the wiring substrate 120.

[0067] The material of the common lead electrode 91 and the individual lead electrodes 92 is not particularly limited as long as it is a conductive material, and for example, gold (Au), platinum (Pt), aluminum (Al), copper (Cu), etc. can be used. In this embodiment, gold (Au) is used for the common lead electrode 91 and the individual lead electrodes 92. The common lead electrode 91 and the individual lead electrodes 92 may also include an adhesion layer made of nickel chromium (NiCr) or the like to improve adhesion with the first electrode 60, the second electrode 80, and the diaphragm 50.

[0068] Although the thickness d3 of the common lead electrode 91 is not particularly limited, in this embodiment it is thicker than the thickness d4 of the second electrode 80 to which the common lead electrode 91 is connected (see FIG. 5). Similarly, although the thickness d5 of the individual lead electrode 92 is not particularly limited, in this embodiment it is thicker than the thickness d6 of the wiring layer 85 to which the individual lead electrode 92 is connected.

[0069] The common lead electrode 91 is extended in the X-axis direction from above the second electrode 80 constituting the common electrode on the piezoelectric layer 70 to above the diaphragm 50 at both ends in the Y-axis direction. The common lead electrode 91, which is the first conductive layer, has a first auxiliary wiring portion 93 extending along the Y-axis direction near the end 12a of the pressure chamber 12 in the -X direction in FIG. 4. The common lead electrode 91 also has a second auxiliary wiring portion 94 extending along the Y-axis direction in a region corresponding to the end 12b of the pressure chamber 12 in the +X direction. The first auxiliary wiring portion 93 and second auxiliary wiring portion 94 are provided continuously along the Y-axis direction for the plurality of piezoelectric elements 300.

[0070] Here, because the second electrode 80 is formed thin, it has high electrical resistance and is prone to bias in the distribution of charge. Therefore, by providing the first auxiliary wiring portion 93 and the second auxiliary wiring portion 94, which have relatively low electrical resistance, on the second electrode 80, bias in the distribution of charge is suppressed. This makes it possible to suppress variations in the amount of displacement when driving the multiple piezoelectric elements 300.

[0071] Furthermore, the second auxiliary wiring portion 94 of the common lead electrode 91 is provided outside the pressure chamber 12 in the X-axis direction. In this embodiment, the active portion 310 of the piezoelectric element 300 extends to the outside of the pressure chamber 12 at both ends of the pressure chamber 12 in the X-axis direction, and the second auxiliary wiring portion 94 extends over this active portion 310, i.e., over the second electrode 80, to the insulating layer 150. For example, in FIG. 4 , the end 94a of the second auxiliary wiring portion 94 in the −X direction is located near the end 12b of the pressure chamber 12, and the end 94b in the +X direction is located on the insulating layer 150. The end 94a of the second auxiliary wiring portion 94 may be located inside the pressure chamber 12.

[0072] On the other hand, the individual lead electrode 92 is provided independently for each piezoelectric element 300, i.e., for each first electrode 60. In Fig. 4, the individual lead electrode 92 is connected via the wiring layer 85 to the vicinity of the +X-direction end 60b of the first electrode 60 extended outside the piezoelectric layer 70, and one end thereof is drawn out in the X-axis direction onto the pressure chamber substrate 10, actually onto the diaphragm 50. The other end of the individual lead electrode 92 is extended in the X-axis direction to the insulating layer 150. For example, the -X-direction end 92a of the individual lead electrode 92 in Fig. 4 is located on the insulating layer 150, and the +X-direction end 92b is located on the diaphragm 50.

[0073] Since the common lead electrode 91 and the individual lead electrodes 92 extend onto the insulating layer 150, when a photosensitive resin is used as the material of the insulating layer 150, it is preferable to form them by, for example, electroless plating. This is because if the common lead electrode 91 and the individual lead electrodes 92 are formed by electrolytic plating, there is a risk that the insulating layer 150 will be damaged.

[0074] As described above, on the -Z direction side of the pressure chamber substrate 10, the vibration plate 50, the first electrode 60, piezoelectric layer 70 and second electrode 80 constituting the piezoelectric element 300, the common lead electrode 91 (second auxiliary wiring portion 94) which is the first conductive layer, the individual lead electrode 92 which is the second conductive layer, and the insulating layer 150 are stacked in a predetermined order for each region.

[0075] 5, in the active area A0 facing the pressure chamber 12, a vibration plate 50, a first electrode 60, a piezoelectric layer 70, and a second electrode 80 are laminated in this order from the pressure chamber substrate 10 side. Furthermore, the area outside the active area A0 in the X-axis direction which is the longitudinal direction of the pressure chamber 12, for example, the area on the +X direction side of the active area A0, includes a first area A1, a second area A2, a third area A3, a fourth area A4, and a fifth area A5.

[0076] The first region A1 is a region in which the vibration plate 50, the first electrode 60, the piezoelectric layer 70, the second electrode 80, the insulating layer 150, and the second auxiliary wiring portion 94 (91), which is the first conductive layer, are stacked in this order from the pressure chamber substrate 10 side.

[0077] Note that, although the first region A1 in this embodiment is a region that includes the diaphragm 50 and the first electrode 60, it is not essential that they be included. The first region A1 does not have to include at least one of the diaphragm 50 and the first electrode 60. Furthermore, in the first region A1, it is preferable that the insulating layer 150 is thicker than the second electrode 80, and that the second auxiliary wiring portion 94 (91) is thicker than the insulating layer 150.

[0078] The second region A2 is a region where the vibration plate 50, the first electrode 60, the piezoelectric layer 70, and the insulating layer 150 are laminated in this order from the pressure chamber substrate 10 side, and where the second electrode 80 and the second auxiliary wiring portion 94 (91) are not laminated. In this embodiment, the second region A2 is a region corresponding to the exposed portion 71 of the piezoelectric layer 70 and is located on the opposite side of the first region A1 from the pressure chamber 12. In other words, the first region A1 is a region on the pressure chamber 12 side of the second region A2, for example, the region adjacent to the second region A2 on the −X direction side in FIG. 5. Note that the second region A2 in this embodiment is a region including the vibration plate 50 and the first electrode 60, but including these is not essential. The second region A2 does not necessarily include at least one of the vibration plate 50 and the first electrode 60.

[0079] Here, an end face 150a of the insulating layer 150 in the second region A2, which faces away from the pressure chamber substrate 10, is located closer to the pressure chamber substrate 10 than an end face 150b of the insulating layer 150 in the first region A1, which faces away from the pressure chamber substrate 10. For example, by over-etching when patterning the common lead electrode 91, the end face 150a of the insulating layer 150 is located closer to the pressure chamber substrate 10 than the end face 150b. As a result, the thickness of the insulating layer 150 in the second region A2 is thinner than the thickness of the insulating layer 150 in the first region A1. Of course, the positions of the end faces of the insulating layer 150 in each region are not particularly limited, and the end faces of the insulating layer 150 may be flat all over.

[0080] The third region A3 is a region adjacent to the second region A2, and is a region in which the vibration plate 50, the first electrode 60, the piezoelectric layer 70, the wiring layer 85, the insulating layer 150, and the individual lead electrode 92 are laminated in this order from the pressure chamber substrate 10 side. In FIG. 5, the region adjacent to the second region A2 on the +X direction side is the third region A3. That is, in the X-axis direction, the second region A2 is located between the first region A1 and the third region A3. Note that the range of the first region A1 in the X-axis direction is not particularly limited, but it is preferably wider than the range of the third region A3.

[0081] The fourth region A4 is a region adjacent to the first region A1, in which the vibration plate 50, the first electrode 60, the piezoelectric layer 70, the second electrode 80, and the second auxiliary wiring portion 94 (91) are laminated in this order from the pressure chamber substrate 10 side, and in which the insulating layer 150 is not laminated. That is, in the fourth region A4, the second electrode 80 and the second auxiliary wiring portion 94 (91) are electrically connected.

[0082] In this embodiment, the region between the first region A1 and the active region A0 in the X-axis direction is the fourth region A4. That is, the first region A1 is located between the fourth region A4 and the second region A2 in the X-axis direction. The range of the fourth region A4 in the X-axis direction is not particularly limited, but it is preferably wider than the range of the first region A1.

[0083] The fifth region A5 is a region where the vibration plate 50, the first electrode 60, and the individual lead electrode 92 are stacked in this order from the pressure chamber substrate 10 side, and where the piezoelectric layer 70, the wiring layer 85, and the insulating layer 150 are not stacked, and is included in the region on the opposite side of the pressure chamber 12 from the third region A3.

[0084] As described above, the recording head 1 has the protective substrate 30 that defines the holding portion 31, which is the space in which the piezoelectric element 300 is housed, and is bonded to the pressure chamber substrate 10 and the like with an adhesive. In this embodiment, the protective substrate 30 is bonded to the insulating layer 150 in the second region A2 via an adhesive 160, as shown in FIG.

[0085] During bonding, the protective substrate 30 is pressed in the Z-axis direction. As a result, in the first region A1 and the third region A3, the adhesive is pushed out from between the protective substrate 30 and the common lead electrode 91 and the individual lead electrode 92, and in fact, the protective substrate 30 may come into substantial contact with the common lead electrode 91 and the individual lead electrode 92.

[0086] Furthermore, the protective substrate 30 is bonded to the second auxiliary wiring portion 94 (91) in the first region A1 via an adhesive 160. The second auxiliary wiring portion 94 (91) to which the protective substrate 30 is bonded has a step 95 whose height in the Z-axis direction varies from the vicinity of the first region A1 to the fourth region A4. When the protective substrate 30 is bonded, excess adhesive 160 is stored in this step 95, and the flow of the adhesive 160 toward the active portion 310 is suppressed.

[0087] As described above, by stacking the vibration plate 50, the first electrode 60, the piezoelectric layer 70, the second electrode 80, the second auxiliary wiring portion 94 (91), the individual lead electrode 92, and the insulating layer 150 in a predetermined order in each region, damage to the piezoelectric layer 70 can be suppressed in the portion corresponding to the exposed portion 71.

[0088] Specifically, in the first region A1, the exposed portion 71 of the piezoelectric layer 70 is covered with the insulating layer 150, thereby preventing moisture from penetrating into the piezoelectric layer 70. Furthermore, in the second region A2, the common lead electrode 91 is located on the insulating layer 150, and in the third region A3, the ends of the individual lead electrodes 92 are located on the insulating layer 150, thereby improving the insulation between the common lead electrode 91 and the individual lead electrodes 92 and preventing short circuits due to migration.

[0089] In particular, since the end face 150a of the insulating layer 150 in the second region A2 is located closer to the pressure chamber substrate 10 than the end face 150b in the first region A1, the migration path between the common lead electrode 91 and the individual lead electrode 92 becomes longer, making it less likely that a short circuit will occur due to migration. Furthermore, during the manufacturing process, residues of the common lead electrode 91 and the individual lead electrode 92 can be reliably removed from the second region A2, making it less likely that a short circuit will occur due to migration.

[0090] Furthermore, by providing the insulating layer 150 on the exposed portion 71, which corresponds to the boundary between the active portion 310 and the inactive portion 320 of the piezoelectric element 300, mechanical damage to the piezoelectric layer 70 at the boundary can be suppressed. As a result, it is possible to suppress destruction of the piezoelectric layer 70. Furthermore, since the insulating layer 150 is provided partially without covering the entire active portion 310 of the piezoelectric element 300, a decrease in the amount of displacement of the piezoelectric element 300 can also be suppressed.

[0091] As described above, the recording head 1 according to this embodiment includes a piezoelectric element 300 including a first electrode 60, a piezoelectric layer 70, and a second electrode 80, a common lead electrode 91 which is a first conductive layer electrically connected to the second electrode 80, an insulating layer 150 formed of an insulating material, a vibration plate 50 which vibrates when driven by the piezoelectric element 300, and a pressure chamber substrate 10 which defines pressure chambers 12 which apply pressure to a liquid when the vibration of the vibration plate 50 occurs.

[0092] In the active area A0 facing the pressure chamber 12, the vibration plate 50, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are laminated in this order from the pressure chamber substrate 10 side. The area outside the active area A0 in the X-axis direction, which is the longitudinal direction of the pressure chamber 12, includes a first area A1 in which the piezoelectric layer 70, the second electrode 80, the insulating layer 150, and the second auxiliary wiring portion 94 (91), which is the first conductive layer, are laminated in this order from the pressure chamber substrate 10 side, and a second area A2 in which the piezoelectric layer 70 and the insulating layer 150 are laminated in this order from the pressure chamber substrate 10 side, but the second electrode 80 (including the wiring layer 85) and the second auxiliary wiring portion 94 are not laminated.

[0093] With this configuration, the adhesiveness of the insulating layer 150 can be improved in the portion corresponding to the exposed portion 71, and damage to the piezoelectric layer 70 can be suppressed, compared to the conventional configuration described below.

[0094] In the conventional configuration, in an adjacent region adjacent to the second region A2 (a region corresponding to the first region A1 according to the present invention), a piezoelectric layer 70, a second electrode 80, a second auxiliary wiring portion 94 (91), and an insulating layer 150 are laminated in this order from the pressure chamber substrate 10 side. In other words, in the conventional configuration, in the adjacent region, the insulating layer 150 is laminated on the -Z direction side of the second auxiliary wiring portion 94 (91).

[0095] In this conventional configuration, the adhesion between the exposed portion 71 on the surface of the piezoelectric layer 70 and the insulating layer 150 may be reduced. This problem occurs due to a step in the insulating layer 150 formed at the boundary between the second region A2 where the second auxiliary wiring portion 94 (91) is not formed and the adjacent region where the second auxiliary wiring portion 94 (91) is formed. In other words, this problem occurs because the height of the insulating layer 150 in the Z-axis direction is significantly different between the second region A2 and the adjacent region.

[0096] If the step in the insulating layer 150 at the boundary between the second region A2 and the adjacent region is large, the process of forming the insulating layer 150 is likely to cause, for example, uneven spin coating or poor adhesion of the resist, and the formation of the insulating layer 150 may become unstable using general methods.

[0097] From the above perspective, by adopting a configuration of the present invention that includes a first region A1 in which the piezoelectric layer 70, the second electrode 80, the insulating layer 150, and the second auxiliary wiring portion 94 (91), which is the first conductive layer, are stacked in this order from the pressure chamber substrate 10 side, and a second region A2 in which the piezoelectric layer 70 and the insulating layer 150 are stacked in this order from the pressure chamber substrate 10 side, and the second electrode 80 (including the wiring layer 85) and the second auxiliary wiring portion 94 are not stacked, the adhesion of the insulating layer 150 can be improved and damage to the piezoelectric layer 70 can be suppressed.

[0098] Here, the thickness of the second auxiliary wiring portion 94 (91), which is the first conductive layer, is thicker than the thickness of the second electrode 80. By thickening the first conductive layer in this way, the electrical resistance is reduced and biased charge distribution in the second electrode 80 is suppressed, while the second electrode 80 can be made relatively thin to improve the efficiency of displacement in the flexible portion of the piezoelectric element 300. Furthermore, according to the present invention, in the first region A1, the insulating layer 150 is laminated on the +Z direction side of the second auxiliary wiring portion 94 (91). Therefore, even if the second auxiliary wiring portion 94 (91) is formed relatively thick, the adhesion of the insulating layer 150 is improved in the portion corresponding to the exposed portion 71, and damage to the piezoelectric layer 70 can be suppressed.

[0099] Furthermore, an end face 150a of the insulating layer 150 in the second region A2 opposite to the pressure chamber substrate 10 is located closer to the pressure chamber substrate 10 than an end face 150b of the insulating layer 150 in the first region A1 opposite to the pressure chamber substrate 10. This lengthens the migration path between the common lead electrode 91 formed on the insulating layer 150 and, for example, the individual lead electrode 92, compared to when the end face 150a of the insulating layer 150 in the second region A2 opposite to the pressure chamber substrate 10 and the end face 150b of the insulating layer 150 in the first region A1 opposite to the pressure chamber substrate 10 are located at the same position in the direction along the Z axis, making it less likely that a short circuit will occur between the common lead electrode 91 and the individual lead electrode 92 due to migration. Furthermore, residues of the common lead electrode 91 and the individual lead electrode 92 can be reliably removed from the second region A2 during the manufacturing process, making it less likely that a short circuit will occur due to migration.

[0100] Furthermore, the thickness of the piezoelectric layer 70 is thinner in the second region A2 than in the first region A1. This increases the difference between the end face 150a of the insulating layer 150 in the second region A2 and the end face 150b of the insulating layer 150 in the first region A1, making it even less likely that a short circuit will occur between the common lead electrode 91 and, for example, the individual lead electrode 92 due to migration. Furthermore, during the manufacturing process, a piezoelectric layer with low insulating properties formed near the interface between the piezoelectric layer 70 and the second electrode 80 can be reliably removed, making it easier to prevent short circuits.

[0101] Furthermore, the region adjacent to the second region A2 includes a third region A3 in which an insulating layer 150 and an individual lead electrode 92, which is a second conductive layer electrically connected to the first electrode 60, are stacked, and the second region A2 is located between the first region A1 and the third region A3 in the longitudinal direction of the pressure chamber 12. In this configuration, a short circuit between the common lead electrode 91 and the individual lead electrode 92 due to migration is less likely to occur.

[0102] Furthermore, the thickness of the individual lead electrode 92, which is the second conductive layer, is greater than the thickness of the first electrode 60. According to the present invention, even when the individual lead electrode 92 is formed relatively thick in this way, damage to the piezoelectric layer 70 can be suppressed in the portion corresponding to the exposed portion 71.

[0103] Furthermore, the region adjacent to the first region A1 includes a fourth region A4 in which the piezoelectric layer 70, the second electrode 80, and the second auxiliary wiring portion 94 are laminated in this order, and the first region A1 is located between the fourth region A4 and the second region A2 in the X-axis direction, which is the longitudinal direction of the pressure chamber 12. Even with this configuration including the fourth region A4, it is possible to suppress damage to the piezoelectric layer 70 in the portion corresponding to the exposed portion 71.

[0104] Furthermore, in the X-axis direction, which is the longitudinal direction of the pressure chamber 12, the first region A1 is wider than the third region A3. This can improve reliability. The fourth region A4 and the first region A1 are active regions 310. In the fourth region A4, the second auxiliary wiring portion 94 is provided directly on the second electrode 80, and the potential difference between the second electrode 80 and the first electrode 60 is relatively large. In the first region A1, the second auxiliary wiring portion 94 is not provided directly on the second electrode 80, and the potential difference between the second electrode 80 and the first electrode 60 is relatively small. On the other hand, the third region A3 is an inactive region 320.

[0105] In other words, in the configuration of this embodiment, the first region A1, which is an active section 310 with a relatively small potential difference between the electrodes, exists between the fourth region A4, which is an active section 310 with a relatively large potential difference between the electrodes, and the third region A3, which is an inactive section 320.

[0106] Therefore, the first region A1 functions as a buffer region between the fourth region A4 and the third region A3. By ensuring a relatively wide range of the first region A1 functioning as such a buffer region, cracks in the piezoelectric layer 70 can be more reliably suppressed.

[0107] Furthermore, the fourth region A4 is wider than the first region A1 in the X-axis direction, which is the longitudinal direction of the pressure chamber 12. This allows the second auxiliary wiring portion 94 to reduce the resistance value of the second electrode 80, while also enabling the recording head 1 to be made smaller.

[0108] The piezoelectric element 30 further includes a protective substrate 30 that defines a space in which the piezoelectric element 300 is housed, and the protective substrate 30 is bonded to the insulating layer 150 in the second region A2 via an adhesive 160. This allows the adhesive 160 to further improve the insulation properties of the exposed portion 71 of the piezoelectric layer 70.

[0109] Furthermore, the region adjacent to the first region A1 includes a fourth region A4 in which a piezoelectric layer 70, a second electrode 80, and a second auxiliary wiring portion 94 (91) which is a first conductive layer are stacked in this order, and in the X-axis direction which is the longitudinal direction of the pressure chamber 12, the first region A1 is located between the fourth region A4 and the second region A2, the second auxiliary wiring portion 94 (91) which is the first conductive layer has a step 95 from the first region A1 to the fourth region A4, and the protective substrate 30 is bonded to the second auxiliary wiring portion 94 (91) which is the first conductive layer in the first region A1 via an adhesive 160.

[0110] As a result, when bonding the protection substrate 30, excess adhesive is stored in the step 95, and the flow of the adhesive toward the active portion 310 is suppressed. Therefore, for example, it is possible to suppress the adhesive from adhering to the active portion 310 and affecting the fluctuation characteristics of the diaphragm 50 and the ejection characteristics of the recording head 1.

[0111] (Embodiment 2) FIG. 7 is an enlarged cross-sectional view showing a main part of a recording head according to the second embodiment. This embodiment is a modified example of the laminated structure of the vibration plate 50, first electrode 60, piezoelectric layer 70, second electrode 80 (including wiring layer 85), second auxiliary wiring portion 94 of common lead electrode 91 which is the first conductive layer, individual lead electrode 92 which is the second conductive layer, and insulating layer 150 in the area outside the pressure chamber 12, and the other configurations are the same as those of embodiment 1. Note that the same members as those of embodiment 1 are given the same reference numerals, and redundant explanations will be omitted.

[0112] 7, the insulating layer 150 according to this embodiment is formed to cover a portion of the exposed portion 71 of the piezoelectric layer 70 in the X-axis direction. That is, the insulating layer 150 is provided continuously from on the second electrode 80 to partway along the exposed portion 71 in the X-axis direction. That is, the insulating layer 150 is provided to cover the end portion 80b of the second electrode 80 as well as the portion of the exposed portion 71 of the piezoelectric layer 70. Note that the end portion 85a of the wiring layer 85 is not covered by the insulating layer 150.

[0113] Therefore, the area outside the active area A0 in the X-axis direction includes the first area A1, the second area A2, the fourth area A4, the fifth area A5, and the sixth area A6, but does not include the third area A3.

[0114] The sixth region A6 is an adjacent region of the second region A2 on the opposite side to the first region A1, and is a region in which the vibration plate 50, the first electrode 60, and the piezoelectric layer 70 are stacked in this order from the pressure chamber substrate 10 side, and the second electrode 80, the insulating layer 150, and the wiring layer 85 are not stacked.

[0115] In the configuration of this embodiment, as in the above-described embodiment, it is possible to suppress damage to the piezoelectric layer 70 in the portion corresponding to the exposed portion 71. Furthermore, since the third region A3 is not provided, it is possible to make the recording head 1 more compact.

[0116] (Embodiment 3) FIG. 8 is an enlarged cross-sectional view showing a main part of a recording head according to a third embodiment. This embodiment is an example in which the position where the protection substrate 30 is bonded by the adhesive layer is changed, and other configurations are the same as those of embodiment 1. Note that the same members as those of embodiment 1 are given the same reference numerals, and redundant explanations will be omitted.

[0117] 8, the protection substrate 30 according to this embodiment is bonded in the fifth region A5 to a laminate including the piezoelectric element 300, the vibration plate 50, and the pressure chamber substrate 10 via an adhesive 160. That is, in Fig. 8, the protection substrate 30 is bonded onto the individual lead electrode 92 via the adhesive 160 in the fifth region A5.

[0118] As described above, the recording head 1 according to this embodiment has a protective substrate 30 that defines a holding portion 31, which is a space that houses the piezoelectric element 300. The protective substrate 30 is bonded to a laminate including the piezoelectric element 300, the vibration plate 50, and the pressure chamber substrate 10 via an adhesive 160 in a fifth region A5, which is an region on the opposite side of the X-axis direction from the pressure chamber 12 in the second region A2. Note that, during bonding, the protective substrate 30 is pressed in the Z-axis direction. For this reason, in the fifth region A5, the adhesive is pushed out from between the protective substrate 30 and the individual lead electrode 92, and in fact, there are cases where the protective substrate 30 is substantially in contact with the individual lead electrode 92.

[0119] Also in the recording head 1 of this embodiment, as in the above-described embodiment, damage to the piezoelectric layer 70 in the portion corresponding to the exposed portion 71 can be suppressed.

[0120] Furthermore, in the configuration of this embodiment, the insulating layer 150 is not sandwiched between the pressure chamber substrate 10 and the protective substrate 30. Therefore, when the protective substrate 30 is bonded, the insulating layer 150 is not pressed, and no residual stress remains between the insulating layer 150 and the protective substrate 30, thereby suppressing peeling of the insulating layer 150. Furthermore, when the protective substrate 30 is bonded, excess adhesive 160 is stored in the gap between the second auxiliary wiring portion 94 (91) and the individual lead electrode 92, that is, in the portion corresponding to the exposed portion 71, and the flow of the adhesive 160 toward the active portion 310 is suppressed.

[0121] Therefore, for example, it is possible to prevent the adhesive 160 from adhering to the active portion 310 and affecting the fluctuation characteristics of the vibration plate 50 and the ejection characteristics of the recording head 1. In addition, the adhesive 160 stored in the gap between the second auxiliary wiring portion 94 (91) and the individual lead electrode 92 covers the exposed portion 71 of the piezoelectric layer 70, which has the effect of improving insulation.

[0122] (Other embodiments) Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

[0123] For example, in the above-described embodiment, the first region A1 and the second region A2 are adjacent to each other, but the first region A1 and the second region A2 do not necessarily have to be adjacent to each other. For example, as shown in Fig. 9, a seventh region A7 may be provided between the first region A1 and the second region A2. The seventh region A7 is a region in which the vibration plate 50, the first electrode 60, the piezoelectric layer 70, the second electrode 80, and the insulating layer 150 are stacked in this order from the pressure chamber substrate 10 side, and in which the second auxiliary wiring portion 94 (91) is not stacked.

[0124] 10, an eighth region A8 may be provided between the first region A1 and the second region A2. The eighth region A8 is a region in which the vibration plate 50, the first electrode 60, the piezoelectric layer 70, the insulating layer 150, and the common lead electrode 91 are laminated in this order from the pressure chamber substrate 10 side, and in which the second electrode 80 is not laminated.

[0125] In the configuration having the seventh region A7 and the eighth region A8, damage to the piezoelectric layer 70 in the portions corresponding to the exposed portions 71 can be suppressed, similar to the above-described embodiment.

[0126] The recording head 1 of each of these embodiments is mounted on an ink jet recording apparatus, which is an example of a liquid ejecting apparatus. Fig. 11 is a schematic diagram showing an example of an ink jet recording apparatus, which is an example of a liquid ejecting apparatus according to an embodiment.

[0127] In the ink jet recording apparatus I shown in Fig. 11, a recording head 1 is provided with a detachable cartridge 2 constituting an ink supply means, and is mounted on a carriage 3. The carriage 3 on which the recording head 1 is mounted is provided so as to be movable in the axial direction of a carriage shaft 5 attached to the apparatus main body 4.

[0128] The driving force of the drive motor 6 is transmitted to the carriage 3 via multiple gears and a timing belt 7 (not shown), causing the carriage 3 carrying the recording head 1 to move along the carriage shaft 5. Meanwhile, the device body 4 is provided with a transport roller 8 as a transport means, and a recording sheet S, which is a recording medium such as paper, is transported by the transport roller 8. Note that the transport means for transporting the recording sheet S is not limited to a transport roller, and may be a belt, a drum, or the like.

[0129] In such an inkjet recording device I, the recording sheet S is transported in the +X direction relative to the recording head 1, and the carriage 3 is moved back and forth in the Y direction relative to the recording sheet S, while ink droplets are ejected from the recording head 1, causing the ink droplets to land over almost the entire surface of the recording sheet S, thereby performing so-called printing.

[0130] Furthermore, in the inkjet recording device I described above, the recording head 1 is mounted on a carriage 3 and moves back and forth in the Y direction, which is the main scanning direction, but the present invention is not limited to this. For example, the present invention can also be applied to a so-called line-type recording device in which the recording head 1 is fixed and printing is performed simply by moving a recording sheet S, such as paper, in the X direction, which is the sub-scanning direction.

[0131] In the above-described embodiment, the present invention has been described using an inkjet recording head as an example of a liquid jet head and an inkjet recording device as an example of a liquid jet device. However, the present invention is broadly applicable to liquid jet heads and liquid jet devices in general. The present invention can also be applied to liquid jet heads and liquid jet devices that eject liquids other than ink. Examples of other liquid jet heads include various recording heads used in image recording devices such as printers, colorant jetting heads used in the manufacture of color filters for liquid crystal displays and the like, electrode material jetting heads used to form electrodes for organic electroluminescent displays (EL) displays, field emission displays (FEDs), and bioorganic material jetting heads used in the manufacture of biochips. The present invention can also be applied to liquid jet devices equipped with such liquid jet heads.

[0132] Furthermore, the present invention is not limited to liquid jet heads typified by ink jet recording heads, but can also be applied to ultrasonic devices, motors, pressure sensors, and piezoelectric devices such as pyroelectric elements and ferroelectric elements.The present invention can also be applied to finished products using these piezoelectric devices, such as liquid jetting devices using the liquid jetting heads described above, ultrasonic sensors using the ultrasonic devices described above, robots using the motors described above as their driving sources, IR sensors using the pyroelectric elements described above, and ferroelectric memories using ferroelectric elements. [Explanation of symbols]

[0133] 1...inkjet recording head (recording head), 2...cartridge, 3...carriage, 4...device body, 5...carriage shaft, 6...drive motor, 7...timing belt, 8...transport roller, 10...pressure chamber substrate (substrate), 12...pressure chamber (recess), 15...communicating plate, 16...nozzle communication passage, 17...first manifold section, 18...second manifold section, 19...supply communication passage, 20...nozzle plate, 21...nozzle, 30...protective substrate, 31...holding section, 32...through hole, 40...case member, 41...accommodating section, 42...third manifold section, 43...connection port, 44...inlet port, 45...compliance substrate, 46...sealing film, 47...fixed substrate, 48...opening, 49...compliance portion, 50...diaphragm, 51...elastic film, 52...insulating film, 60...first electrode, 70...piezoelectric layer, 71...exposed portion, 72...recess, 80...second electrode, 85...wiring layer, 91...common lead electrode, 92...individual lead electrode, 93...first auxiliary wiring portion, 94...second auxiliary wiring portion, 95...step, 100...manifold, 120...wiring board, 121...drive circuit, 150...insulating layer, 160...adhesive, 300...piezoelectric element, 310...active portion, 320...inactive portion, I...inkjet recording apparatus (recording apparatus), S...recording sheet, A0...active region, A1...first region, A2...second region, A3...third region, A4...fourth region, A5...fifth region, A6...sixth region, A7...seventh region, A8...eighth region

Claims

1. a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode; a first conductive layer electrically connected to the second electrode; an insulating layer formed of an insulating material; a vibration plate that vibrates when driven by the piezoelectric element; a pressure chamber substrate defining a pressure chamber for applying pressure to liquid by vibration of the vibration plate; having The active area facing the pressure chamber includes the vibration plate, the first electrode, and the piezoelectric layer. , the second electrode are laminated in this order from the pressure chamber substrate side, The area outside the active area in the longitudinal direction of the pressure chamber is The piezoelectric layer, the second electrode, the insulating layer, and the first conductive layer form the pressure chamber substrate. A first region laminated in this order from the plate side; The piezoelectric layer and the insulating layer are laminated in this order from the pressure chamber substrate side, and a second region in which the second electrode and the first conductive layer are not laminated. A liquid jet head comprising:

2. The thickness of the first conductive layer is greater than the thickness of the second electrode. The liquid jet head according to claim 1 .

3. The end surface of the insulating layer in the second region opposite to the pressure chamber substrate is a pressure chamber substrate side of the end face of the insulating layer on the opposite side to the pressure chamber substrate, do The liquid jet head according to claim 2 .

4. The thickness of the piezoelectric layer is thinner in the second region than in the first region. The liquid jet head according to claim 3 .

5. The region adjacent to the second region is a third region in which the insulating layer and a second conductive layer electrically connected to the first electrode are laminated; Including, In the longitudinal direction of the pressure chamber, the second region includes the first region and the third region, Located between 5. The liquid jet head according to claim 3, wherein the first and second electrodes are arranged in a first direction.

6. The thickness of the second conductive layer is greater than the thickness of the first electrode. The liquid jet head according to claim 5 .

7. The region adjacent to the first region is a fourth region in which the piezoelectric layer, the second electrode, and the first conductive layer are laminated in this order; Including, In the longitudinal direction of the pressure chamber, the first region includes the fourth region and the second region, Located between The liquid jet head according to claim 5 .

8. In the longitudinal direction of the pressure chamber, the first region is wider than the third region. The liquid jet head according to claim 7 .

9. In the longitudinal direction of the pressure chamber, the fourth region is wider than the first region. The liquid jet head according to claim 7 .

10. a protective substrate that defines a space in which the piezoelectric element is housed; The protection substrate is bonded to the insulating layer in the second region via an adhesive. The liquid jet head according to claim 1 , wherein the liquid jet head is a liquid jet head.

11. The region adjacent to the first region is a fourth region in which the piezoelectric layer, the second electrode, and the first conductive layer are laminated in this order; Including, In the longitudinal direction of the pressure chamber, the first region is between the fourth region and the second region. Located in the first conductive layer has a step from the first region to the fourth region, The protection substrate is bonded to the first conductive layer in the first region via an adhesive. The liquid jet head according to claim 10 .

12. a protective substrate that defines a space in which the piezoelectric element is housed; The protection substrate includes a piezoelectric element in a region of the second region on the opposite side to the pressure chamber. and bonded to a laminate including the vibration plate and the pressure chamber substrate via an adhesive. The liquid jet head according to claim 1 , wherein the liquid jet head is a liquid jet head.

13. The liquid jet head according to any one of claims 1 to 4 is provided. A liquid ejection apparatus comprising:

14. A substrate having a recess; A diaphragm provided on one surface side of the substrate; a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode; a first conductive layer electrically connected to the second electrode; an insulating layer formed of an insulating material; The active area facing the recess includes the vibration plate, the first electrode, the piezoelectric layer, and the second electrode are laminated in this order from the substrate side, The region outside the active region in the longitudinal direction of the recess is The piezoelectric layer, the second electrode, the insulating layer, and the first conductive layer are arranged on the substrate side. a first region laminated in this order from the first region; The piezoelectric layer and the insulating layer are laminated in this order from the substrate side, and the second an electrode and a second region where the first conductive layer is not laminated. A piezoelectric device characterized by:

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