Piezoelectric device, liquid ejecting head, liquid ejecting apparatus, and method for manufacturing piezoelectric device

Abstract

The present application provides a piezoelectric device, a liquid ejection head, a liquid ejection apparatus, and a manufacturing method of a piezoelectric device for solving a problem that a piezoelectric actuator can be damaged due to heat generation of a piezoelectric layer at the time of driving. When one region of two regions in a second direction intersecting a first direction of a second electrode (80) farther from an end portion (80b) of the second electrode (80) is set as a first region (S1), and one region closer to the end portion (80b) of the second electrode (80) is set as a second region (S2), a piezoelectric layer (70) of the first region (S1) is subjected to (100) face orientation, and a (100) face orientation rate of the piezoelectric layer of the second region (S2) is lower than the (100) face orientation rate of the piezoelectric layer (70) of the first region (S1).

Description

Piezoelectric devices, liquid jet heads, liquid jetting devices, and manufacturing methods of piezoelectric devices Technical Field

[0001] The present invention relates to a piezoelectric device, a liquid jet head, a liquid jetting device, and a method for manufacturing a piezoelectric device, wherein the piezoelectric device comprises a vibrating plate and a piezoelectric actuator having a first electrode, a piezoelectric body layer, and a second electrode. Background Technology

[0002] As a representative example of a piezoelectric device, namely a liquid ejector head, an inkjet recording head that ejects ink droplets can be cited. One known inkjet recording head includes a flow channel forming substrate having a pressure chamber communicating with, for example, a nozzle, and a piezoelectric actuator disposed on one side of the flow channel forming substrate via a vibrating plate. The piezoelectric actuator causes a pressure change in the ink within the pressure chamber, thereby ejecting ink droplets from the nozzle.

[0003] Furthermore, as a piezoelectric actuator, one known piezoelectric actuator comprises a first electrode, a piezoelectric layer, and a second electrode. The first electrode is formed on a vibrating plate, the piezoelectric layer is formed on the first electrode using a piezoelectric material with electromechanical conversion properties, and the second electrode is disposed on the piezoelectric layer. In this piezoelectric actuator structure, cracks or burn-out may occur in the piezoelectric layer due to flexural deformation. To suppress the occurrence of such undesirable phenomena, various structures of piezoelectric actuators (piezoelectric elements) have been proposed (for example, see Patent Document 1).

[0004] Patent Document 1 describes a situation where the piezoelectric element is extended to the outer side of the opening of the pressure chamber cavity, and the width of the first electrode layer constituting the piezoelectric element is narrower than the area corresponding to the pressure chamber cavity on the outer side of the pressure chamber cavity.

[0005] Although the structure in which the piezoelectric actuator extends to the outside of the pressure chamber presents a problem of cracking in the piezoelectric layer as described above, the piezoelectric layer extending to the outside of the pressure chamber does not flex or deform when voltage is applied. Therefore, heat is generated due to the flowing current. With the improvement of the performance of the piezoelectric layer, the heat generated by the piezoelectric layer tends to increase, potentially damaging the piezoelectric actuator.

[0006] Furthermore, this problem is not limited to liquid ejection heads, such as inkjet recorders that eject ink; it also exists in other piezoelectric devices.

[0007] Patent Document 1: Japanese Patent Application Publication No. 2015-171809 Summary of the Invention

[0008] One aspect of the present invention that solves the above-mentioned problems is a piezoelectric device, characterized in that it comprises: a substrate having a plurality of recesses; a vibrating plate disposed on one side of the substrate; and a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on the side of the vibrating plate opposite to the substrate, wherein when a region farther from the end of the second electrode is designated as a first region and a region closer to the end of the second electrode is designated as a second region, the piezoelectric layer in the first region is preferably oriented in a (100) plane, and the (100) plane orientation rate of the piezoelectric layer in the second region is lower than the (100) plane orientation rate of the piezoelectric layer in the first region.

[0009] Another aspect of the invention relates to a liquid injection head, characterized by comprising: a substrate having a plurality of recesses; a vibrating plate disposed on one side of the substrate; and a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on the side of the vibrating plate opposite to the substrate, wherein when a region farther from the end of the second electrode in two regions in a second direction intersecting the first direction is designated as a first region, and a region closer to the end of the second electrode is designated as a second region, the piezoelectric layer in the first region is preferably oriented in a (100) plane, and the (100) plane orientation rate of the piezoelectric layer in the second region is lower than the (100) plane orientation rate of the piezoelectric layer in the first region.

[0010] Furthermore, another aspect of the present invention is a liquid injection device, characterized by having the aforementioned liquid injection head.

[0011] Furthermore, another aspect of the present invention relates to a method for manufacturing a piezoelectric device, characterized in that the piezoelectric device comprises: a substrate having a plurality of recesses; a vibrating plate disposed on one side of the substrate; and a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on the side of the vibrating plate opposite to the substrate, wherein when a region farther from the end of the second electrode is designated as a first region and a region closer to the end of the second electrode is designated as a second region, the piezoelectric material in the first region... The piezoelectric body layer is preferentially oriented in a (100) plane, and the (100) plane orientation rate of the piezoelectric body layer in the second region is lower than that of the piezoelectric body layer in the first region. In the manufacturing method of the piezoelectric device, as a step of forming the piezoelectric actuator by stacking the first electrode, the piezoelectric body layer and the second electrode on the surface of the vibrating plate disposed on the substrate, there is a step of forming an orientation control layer for controlling the crystal orientation of the piezoelectric body layer. In the step of forming the orientation control layer, the orientation control layer is formed to have different thicknesses in the first region and the second region. Attached Figure Description

[0012] Figure 1 is an exploded perspective view of the recording head according to Embodiment 1.

[0013] Figure 2 is a plan view of the recording head according to Embodiment 1.

[0014] Figure 3 is a cross-sectional view of the recording head according to Embodiment 1.

[0015] Figure 4 is a cross-sectional view of the main parts of the recording head involved in Embodiment 1.

[0016] Figure 5 is a cross-sectional view of the recording head according to Embodiment 1.

[0017] Figure 6 is a partial cross-sectional view showing a modified example of the recording head according to Embodiment 1.

[0018] Figure 7 is a partial cross-sectional view showing a modified example of the recording head according to Embodiment 1.

[0019] Figure 8 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0020] Figure 9 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0021] Figure 10 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0022] Figure 11 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0023] Figure 12 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0024] Figure 13 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0025] Figure 14 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0026] Figure 15 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0027] Figure 16 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0028] Figure 17 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0029] Figure 18 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0030] Figure 19 is a cross-sectional view showing the manufacturing method of the recording head according to Embodiment 1.

[0031] Figure 20 is a cross-sectional view illustrating another example of the method for manufacturing the recording head according to Embodiment 1.

[0032] Figure 21 is a cross-sectional view of the main parts of the recording head according to Embodiment 2.

[0033] Figure 22 is a cross-sectional view of the main parts of the recording head according to Embodiment 2.

[0034] Figure 23 is a diagram showing the general structure of a recording device according to one embodiment. Detailed Implementation

[0035] The present invention will now be described in detail based on embodiments. However, the following description is only one aspect of the invention, and the structure of the invention can be modified in any way within the scope of the invention. In the various figures, the same symbols are used to mark the same parts, and repeated descriptions are omitted.

[0036] Furthermore, in each diagram, X, Y, and Z represent three mutually orthogonal spatial axes. In this specification, the directions along these axes will be designated as the X direction, Y direction, and Z direction. The direction in which the arrows in each diagram point will be designated as the positive (+) direction, and the opposite direction of the arrows will be designated as the negative (-) direction, and will be explained accordingly. Additionally, the Z direction represents the vertical direction, the +Z direction represents the vertical downward direction, and the -Z direction represents the vertical upward direction. Moreover, the three spatial axes X, Y, and Z, for which no positive or negative directions are defined, will be explained as the X-axis, Y-axis, and Z-axis.

[0037] Implementation Method 1

[0038] Figure 1 is an exploded perspective view of an example of a liquid jet head according to Embodiment 1 of the present invention, namely an inkjet recording head. Figure 2 is a plan view of the recording head. Figure 3 is a cross-sectional view along line A-A' of Figure 2, Figure 4 is an enlarged view of the piezoelectric actuator portion in Figure 3, and Figure 5 is a cross-sectional view along line B-B' of Figure 2, and is also an enlarged view of the piezoelectric actuator portion.

[0039] As shown in the figure, an example of the liquid ejection head of this embodiment, namely an inkjet recording head (hereinafter, also referred to as recording head 1), is a recording head that ejects ink droplets in the Z-axis direction, which is the first direction, and more specifically in the +Z direction.

[0040] As an example of a substrate, the inkjet recording head 1 includes a channel forming substrate 10. The channel forming substrate 10 is made of, for example, a silicon substrate, a glass substrate, an SOI (Silicon-On-Insulator) substrate, or various ceramic substrates. In addition, the channel forming substrate 10 can be a substrate with a (100) plane preferred orientation or a substrate with a (110) plane preferred orientation.

[0041] In the flow channel forming substrate 10, a plurality of pressure chambers 12 are arranged in two rows in the X-axis direction, which is a second direction intersecting the first direction, i.e., the Z-axis direction. That is, the plurality of pressure chambers 12 constituting each row are arranged along the Y-axis direction, which is a third direction intersecting the X-axis direction.

[0042] The pressure chambers 12 constituting each column are arranged in a straight line along the Y-axis such that their positions in the X-axis direction are the same. Adjacent pressure chambers 12 in the Y-axis direction are separated by partitions 11. Of course, the arrangement of the pressure chambers 12 is not particularly limited. For example, the arrangement of multiple pressure chambers 12 arranged side-by-side in the Y-axis direction can also be a so-called staggered arrangement, where each pressure chamber 12 is staggered in the X-axis direction at every other position.

[0043] Furthermore, in this embodiment, the pressure chamber 12 is longer in the X-axis direction than in the Y-axis direction when viewed from the +Z direction plane; for example, it is formed as a rectangle. Of course, the shape of the pressure chamber 12 when viewed from the +Z direction plane is not particularly limited, and it can also be a parallelogram, a polygon, a circle, an oblong shape, etc. Additionally, the oblong shape mentioned here refers to a shape based on a rectangle with semicircular ends in the length direction, and can include rounded rectangular shapes, elliptical shapes, egg-shaped shapes, etc.

[0044] On the +Z direction side of the flow channel forming substrate 10, a connecting plate 15, a nozzle plate 20, and a plastic substrate 45 are stacked in sequence.

[0045] The connecting plate 15 includes a nozzle communication channel 16 that connects the pressure chamber 12 and the nozzle 21. Furthermore, the connecting plate 15 includes a first manifold portion 17 and a second manifold portion 18 that form part of a manifold 100 connecting the plurality of pressure chambers 12. The first manifold portion 17 extends through the connecting plate 15 in the Z-axis direction. The second manifold portion 18 is configured to have an opening on the +Z direction side without extending through the connecting plate 15 in the Z-axis direction.

[0046] Furthermore, in the connecting plate 15, a supply connecting channel 19, which communicates with one end of the pressure chamber 12 in the X-axis direction, is independently provided in each of the pressure chambers 12. The supply connecting channel 19 connects the second manifold 18 to each pressure chamber 12, thereby supplying ink from the manifold 100 to each pressure chamber 12.

[0047] The connecting plate 15 can be made of silicon substrate, glass substrate, SOI substrate, various ceramic substrates, metal substrates, etc. For example, stainless steel substrates can be used as metal substrates. Furthermore, it is preferable that the connecting plate 15 is made of a material with a coefficient of thermal expansion that is approximately the same as that of the flow channel forming substrate 10. Therefore, when the temperature of the flow channel forming substrate 10 and the connecting plate 15 changes, warping of the flow channel forming substrate 10 and the connecting plate 15 caused by differences in their coefficients of thermal expansion can be suppressed.

[0048] The nozzle plate 20 is disposed on the surface of the connecting plate 15 opposite to the flow channel forming substrate 10, i.e., on the +Z direction side. In the nozzle plate 20, nozzles 21 are formed that communicate with each pressure chamber 12 via the nozzle connecting channel 16.

[0049] In this embodiment, a plurality of nozzles 21 are arranged side-by-side in a column along the Y-axis. Furthermore, two columns of nozzles 21 are arranged in the X-axis direction on the nozzle plate 20. That is, the nozzles 21 in each column are arranged in the same position along the X-axis. However, the arrangement of the nozzles 21 is not particularly limited. For example, the nozzles 21 arranged side-by-side in the Y-axis direction may be arranged at positions staggered every other nozzle in the X-axis direction.

[0050] The material of the nozzle plate 20 is not particularly limited; for example, silicon substrates, glass substrates, SOI substrates, various ceramic substrates, and metal substrates can be used. For example, stainless steel substrates can be used as metal plates. Furthermore, organic materials such as polyimide resins can also be used as the material of the nozzle plate 20. Preferably, the nozzle plate 20 uses a material with a coefficient of thermal expansion approximately the same as that of the connecting plate 15. Therefore, when the temperature of the nozzle plate 20 and the connecting plate 15 changes, warping of the nozzle plate 20 and the connecting plate 15 due to differences in their coefficients of thermal expansion can be suppressed.

[0051] A malleable substrate 45 is disposed together with the nozzle plate 20 on the surface of the connecting plate 15 opposite to the flow channel forming substrate 10, i.e., on the +Z direction side. This malleable substrate 45 is disposed around the nozzle plate 20 and seals the openings of the first manifold portion 17 and the second manifold portion 18 disposed in the connecting plate 15. In this embodiment, the malleable substrate 45 includes a sealing film 46 made of a flexible thin film and a fixing substrate 47 made of a rigid material such as metal. The region of the fixing substrate 47 opposite the manifold 100 becomes an opening 48 that is completely removed in the thickness direction. Therefore, one surface of the manifold 100 becomes a malleable portion 49 sealed only by the flexible sealing film 46.

[0052] On the other hand, although details will be described later, a vibrating plate 50 and a piezoelectric actuator 300 are provided on the side of the flow channel forming substrate 10 opposite to the nozzle plate 20, i.e., the -Z direction side. The piezoelectric actuator 300 causes the vibrating plate 50 to flex and deform, thereby causing a pressure change in the ink within the pressure chamber 12. Furthermore, Figure 3 is a diagram illustrating the overall structure of the recording head 1, and a simplified representation of the structure of the piezoelectric actuator 300 is shown.

[0053] On the Z-direction side of the flow channel forming substrate 10, a protective substrate 30 having approximately the same size as the flow channel forming substrate 10 is further bonded by an adhesive or the like. The protective substrate 30 has a holding portion 31 that serves as a space to protect the piezoelectric actuators 300. The holding portions 31 are independently provided for each row of piezoelectric actuators 300 arranged side-by-side in the Y-axis direction, and two are formed side-by-side in the X-axis direction. Furthermore, a through hole 32 is provided in the protective substrate 30, which extends in the Z-axis direction between the two holding portions 31 arranged side-by-side in the X-axis direction.

[0054] Furthermore, a housing component 40 is fixed on the protective substrate 30, which, together with the flow channel forming substrate 10, divides the manifold 100 that communicates with the plurality of pressure chambers 12. The housing component 40 has a shape that is substantially the same as the aforementioned connecting plate 15 when viewed in plan view. The housing component 40 is engaged with both the protective substrate 30 and the aforementioned connecting plate 15.

[0055] The housing component 40 has a storage portion 41 on the protective substrate 30 side, which has a depth sufficient to accommodate the flow channel forming substrate 10 and the protective substrate 30. The storage portion 41 has an opening area that is larger than the surface of the protective substrate 30 that engages with the flow channel forming substrate 10. Furthermore, when the flow channel forming substrate 10 and the protective substrate 30 are housed within the storage portion 41, the opening surface of the storage portion 41 on the nozzle plate 20 side is sealed by the connecting plate 15.

[0056] Furthermore, in the outer casing component 40, third manifold sections 42 are respectively divided on the two outer sides of the receiving portion 41 in the X-axis direction. Moreover, the manifold 100 of this embodiment is constituted by the first manifold section 17, the second manifold section 18, and the third manifold section 42 provided in the connecting plate 15. The manifold 100 is continuously provided in the Y-axis direction, and the supply communication channels 19 connecting each pressure chamber 12 and the manifold 100 are arranged side by side in the Y-axis direction.

[0057] Furthermore, the housing component 40 is provided with an inlet 44 for communicating with the manifold 100 to supply ink to each manifold 100. Also, the housing component 40 is provided with a connection port 43, which communicates with the through hole 32 of the protective substrate 30 and allows the wiring board 120 to be inserted through it.

[0058] In the recording head 1 of this embodiment, ink is taken in through the inlet 44 connected to an external ink supply unit (not shown). After the head is filled with ink from the manifold 100 to the nozzle 21, a voltage is applied to each piezoelectric actuator 300 corresponding to the pressure chamber 12 according to the recording signal from the drive circuit 121. As a result, the vibrating plate 50 and the piezoelectric actuators 300 flex and deform together, thereby increasing the pressure in each pressure chamber 12 and ejecting ink droplets from each nozzle 21.

[0059] The structure of the piezoelectric actuator 300 according to this embodiment will be described below. As described above, the piezoelectric actuator 300 is disposed on the surface of the flow channel forming substrate 10 opposite to the nozzle plate 20, with the vibrating plate 50 in between.

[0060] As shown in Figures 3-5, the vibrating plate 50 is composed of an elastic membrane 51 and an insulating membrane 52. The elastic membrane 51 is disposed on the flow channel forming substrate 10 side and is made of silicon oxide, while the insulating membrane 52 is disposed on the elastic membrane 51 and is made of zirconium oxide. The liquid flow channels, such as the pressure chamber 12, are formed by anisotropic etching of the flow channel forming substrate 10 starting from the +Z direction side. The -Z direction side of the liquid flow channels, such as the pressure chamber 12, is composed of the elastic membrane 51.

[0061] Furthermore, the structure of the vibrating plate 50 is not particularly limited. The vibrating plate 50 may be composed of either an elastic membrane 51 or an insulating membrane 52, and may also include other membranes besides the elastic membrane 51 and the insulating membrane 52. Examples of other membrane materials include silicon and silicon nitride.

[0062] The piezoelectric actuator 300 is a pressure generating unit that causes pressure changes in the ink within the pressure chamber 12, and is also called a piezoelectric element. This piezoelectric actuator 300 includes a first electrode 60, a piezoelectric layer 70, and a second electrode 80, which are sequentially stacked from the +Z direction side (which is the vibrating plate 50 side) towards the -Z direction side. In other words, the piezoelectric actuator 300 includes a first electrode 60, a piezoelectric layer 70, and a second electrode 80, which are sequentially stacked relative to the vibrating plate 50 along the Z-axis direction (which is the first direction) and in this embodiment towards the -Z direction side.

[0063] However, the portion of the piezoelectric actuator 300 that generates piezoelectric strain in the piezoelectric layer 70 when a voltage is applied between the first electrode 60 and the second electrode 80 is called the active portion 310. Conversely, the portion of the piezoelectric layer 70 that does not generate piezoelectric strain is called the inactive portion 320. That is, the portion of the piezoelectric layer 70 in the piezoelectric actuator 300 sandwiched between the first electrode 60 and the second electrode 80 is the active portion 310, and the portion of the piezoelectric layer 70 not sandwiched between the first electrode 60 and the second electrode is the inactive portion 320. Furthermore, when the piezoelectric actuator 300 is driven, the portion that actually displaces in the Z-axis direction is called the flexible portion, and the portion that does not displace in the Z-axis direction is called the non-flexible portion. That is, the portion of the piezoelectric actuator 300 opposite the pressure chamber 12 in the Z-axis direction is called the flexible portion, and the outer portion of the pressure chamber 12 is called the non-flexible portion.

[0064] Generally, the electrode of one of the active parts 310 is configured as an independent electrode for each active part 310, and the electrode of the other part is configured as a common electrode shared by multiple active parts 310. In this embodiment, the first electrode 60 is configured as an independent electrode, and the second electrode 80 is configured as a common electrode.

[0065] Specifically, the first electrode 60 is divided for each pressure chamber 12, thereby forming an independent electrode for each active part 310. The first electrode 60 is formed in the Y-axis direction with a width narrower than the width of the pressure chamber 12. That is, in the Y-axis direction, the end of the first electrode 60 is located inside the region opposite to the pressure chamber 12.

[0066] Furthermore, the +X direction end 60a and the -X direction end 60b of the first electrode 60 are respectively disposed on the outside of the pressure chamber 12. As shown in FIG4, the +X direction end 60a of the first electrode 60 is disposed at a position closer to the +X direction than the +X direction end 12a of the pressure chamber 12. The -X direction end 60b of the first electrode 60 is disposed at a position closer to the -X direction than the -X direction end 12b of the pressure chamber 12.

[0067] Although the material of the first electrode 60 is not specifically limited, conductive materials such as metals like iridium or platinum, or conductive metal oxides such as indium tin oxide (abbreviated as ITO) are used.

[0068] Furthermore, as shown in FIG2, the piezoelectric layer 70 is continuously arranged in the Y-axis direction with a predetermined length in the X-axis direction. That is, the piezoelectric layer 70 is continuously arranged along the side-by-side arrangement direction of the pressure chamber 12 with a predetermined thickness. Although the thickness of the piezoelectric layer 70 is not particularly limited, it is formed with a thickness of about 1 to 4 μm. Furthermore, as shown in FIG4, the length of the piezoelectric layer 70 in the X-axis direction is longer than the length in the X-axis direction that is the length direction of the pressure chamber 12. Therefore, the piezoelectric layer 70 extends to the outside of the pressure chamber 12 on both sides in the X-axis direction. In this way, by extending the piezoelectric layer 70 to the outside of the pressure chamber 12 in the X-axis direction, the strength of the vibrating plate 50 is improved. Therefore, when the piezoelectric actuator 300 is displaced by driving the active part 310, the generation of cracks or the like in the piezoelectric layer 70 can be suppressed.

[0069] Furthermore, as shown in FIG4, the +X direction end 70a of the piezoelectric layer 70 is located further outward than the end 60a of the first electrode 60. That is, the +X direction end 60a of the first electrode 60 is covered by the piezoelectric layer 70. On the other hand, the -X direction end 70b of the piezoelectric layer 70 is located further inward than the end 60b of the first electrode 60, and the -X direction end 60b of the first electrode 60 is not covered by the piezoelectric layer 70.

[0070] Furthermore, as shown in Figures 2 and 5, grooves 71, which are thinner than other areas, are formed on the piezoelectric layer 70 corresponding to each partition 11. In this embodiment, the grooves 71 are formed by completely removing the piezoelectric layer 70 in the Z-axis direction. That is, the phrase "the piezoelectric layer 70 has a thinner portion compared to other areas" also includes the portion obtained after completely removing the piezoelectric layer 70 in the Z-axis direction. Of course, the piezoelectric layer 70 may also be formed thinner than other portions on the bottom surface of the grooves 71.

[0071] Furthermore, the length of the groove 71 in the Y-axis direction, i.e., the width of the groove 71, is the same as or larger than the width of the partition wall 11. In this embodiment, the width of the groove 71 is greater than the width of the partition wall 11.

[0072] Such a groove 71 is formed in a rectangular shape when viewed from the -Z side plane. Of course, the shape of the groove 71 when viewed from the -Z side plane is not limited to a rectangular shape, and can be a polygon with more than one pentagon, or a circular or elliptical shape, etc.

[0073] Since the rigidity of the portion of the vibrating plate 50 that faces the end of the pressure chamber 12 in the Y-axis direction, namely the arm portion of the vibrating plate 50, is suppressed by providing the groove 71 on the piezoelectric layer 70, the piezoelectric actuator 300 can be displaced more effectively.

[0074] The piezoelectric layer 70 can be exemplified by a perovskite-structured crystalline film (perovskite-type crystal) formed on the first electrode 60, which represents electromechanical conversion. As the material for the piezoelectric layer 70, for example, ferroelectric piezoelectric materials such as lead zirconate titanate (PZT) can be used, or materials obtained by adding metal oxides such as niobium oxide, nickel oxide, or magnesium oxide. Specifically, lead titanate (PbTiO3), lead zirconate titanate (Pb(Zr,Ti)O3), lead zirconate (PbZrO3), lanthanum lead titanate ((Pb,La),TiO3), lanthanum lead zirconate titanate ((Pb,La)(Zr,Ti)O3), or lead magnesium niobate zirconate titanate (Pb(Zr,Ti)(Mg,Nb)O3) can be used. In this embodiment, lead zirconate titanate (PZT) is used as the piezoelectric layer 70.

[0075] Furthermore, the material used for the piezoelectric layer 70 is not limited to lead-based piezoelectric materials containing lead; lead-free piezoelectric materials can also be used. Examples of lead-free piezoelectric materials include, for instance, bismuth ferrite ((BiFeO3, abbreviated as "BFO")), barium titanate ((BaTiO3, abbreviated as "BT")), potassium sodium niobate ((K,Na)(NbO3, abbreviated as "KNN")), lithium sodium potassium niobate ((K,Na,Li)(NbO3)), potassium lithium lithium niobate tantalate ((K,Na,Li)(Nb,Ta)O3), and potassium bismuth titanate ((Bi... 1 / 2 K 1 / 2 TiO3 (abbreviated as "BKT"), sodium bismuth titanate (Bi 1 / 2 Na 1 / 2 TiO3 (abbreviated as "BNT"), bismuth manganate (BiMnO3 (abbreviated as "BM"), and composite oxides containing bismuth, sodium, titanium, and iron with a perovskite structure (x[(Bi x K 1-x (1-x)[BiFeO3]-(1-x)[BiFeO3], abbreviated as "BKT-BF"), a composite oxide containing bismuth, iron, barium, and titanium and having a perovskite structure ((1-x)[BiFeO3]-x[BaTiO3], abbreviated as "BFO-BT"), or a substance obtained by adding metals such as manganese, cobalt, and chromium ((1-x)[Bi(FeO3]-x)[BiFeO3], abbreviated as "BKT-BF"), or a composite oxide containing bismuth, iron, barium, and titanium and having a perovskite structure ((1-x)[BiFeO3]-x[BaTiO3], abbreviated as "BFO-BT"), or a substance obtained by adding metals such as manganese, cobalt, and chromium ((1-x)[Bi(FeO3]-x)[Bi ... 1- y M y [O3]-x[BaTiO3] (M is Mn, Co or Cr) etc.

[0076] As shown in Figures 4 and 5, the second electrode 80 is disposed on the side of the piezoelectric layer 70 opposite to the first electrode 60, i.e., the -Z direction side, and constitutes a common electrode shared by multiple active portions 310. The second electrode 80 has a predetermined length in the X-axis direction, and is thus continuously disposed in the Y-axis direction. This second electrode 80 is also disposed on the inner surface of the groove portion 71, i.e., on the side surface of the groove portion 71 of the piezoelectric layer 70, and on the insulating film 52 that serves as the bottom surface of the groove portion 71. Furthermore, regarding the interior of the groove portion 71, the second electrode 80 may be disposed only on a portion of the inner surface of the groove portion 71, or it may not be disposed on the entire inner surface of the groove portion 71.

[0077] Furthermore, as shown in FIG4, the +X direction end 80a of the second electrode 80 is configured to be located further outward than the +X direction end 60a of the first electrode 60 covered by the piezoelectric layer 70. That is, the +X direction end 80a of the second electrode 80 is located further outward than the +X direction end 12a of the pressure chamber 12 and further outward than the end 60a of the first electrode 60. In this embodiment, the +X direction end 80a of the second electrode 80 substantially coincides with the end 70a of the piezoelectric layer 70. 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.

[0078] On the other hand, although the -X direction end 80b of the second electrode 80 is positioned outward compared to the -X direction end 12b of the pressure chamber 12, it is positioned inward compared to the X-axis direction end 70b of the piezoelectric layer 70. As described above, the -X direction end 70b of the piezoelectric layer 70 is located inward compared to the end 60b of the first electrode 60. Therefore, the -X direction end 80b of the second electrode 80 is located on the piezoelectric layer 70, which is inward compared to the -X direction end 60b of the first electrode 60. Therefore, there is a portion of the surface of the piezoelectric layer 70 exposed outside the -X direction end 80b of the second electrode 80.

[0079] Thus, since the -X direction end 80b of the second electrode 80 is positioned closer to the +X direction side than the -X direction end of the piezoelectric layer 70 and the first electrode 60, 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 -X direction end 80b of the second electrode 80.

[0080] Although the material of the second electrode 80 is not particularly limited, it is preferably a conductive material, such as a metal like iridium or platinum, or a conductive metal oxide like indium tin oxide, similar to the first electrode 60.

[0081] Furthermore, on the outer side of the -X direction end 80b of the second electrode 80, that is, further towards the -X direction side of the end 80b of the second electrode 80, a wiring portion 85 is provided, which, although composed of the same layer as the second electrode 80, is not electrically continuous with the second electrode 80. Moreover, the wiring portion 85 is formed from the piezoelectric layer 70 across the first electrode 60, which extends in the -X direction compared to the piezoelectric layer 70, and is spaced apart from the -X direction end 80b of the second electrode 80. This wiring portion 85 is provided independently for each active portion 310. That is, multiple wiring portions 85 are arranged at predetermined intervals along the Y-axis direction. While the wiring portion 85 may also be formed of a layer independent of the second electrode 80, it is preferable that it is formed of the same layer as the second electrode 80. This simplifies the manufacturing process of the wiring portion 85, thereby reducing costs.

[0082] Furthermore, an independent lead electrode 91 and a common lead electrode 92 serving as a common driving electrode are respectively connected to the first electrode 60 and the second electrode 80 constituting the piezoelectric actuator 300. A flexible wiring board 120 is connected to the ends of the independent lead electrode 91 and the common lead electrode 92 opposite to the ends connected to the piezoelectric actuator 300. In this embodiment, the independent lead electrode 91 and the common lead electrode 92 are extended and exposed within a through hole 32 formed in the protective substrate 30, and are electrically connected to the wiring board 120 within this through hole 32. A driving circuit 121 is mounted on the wiring board 120, the driving circuit 121 having a switching element for driving the piezoelectric actuator 300.

[0083] Although the individual lead electrode 91 and the common lead electrode 92 are formed from the same layer in this embodiment, they are formed in a non-electrically continuous manner. Therefore, compared to forming the individual lead electrode 91 and the common lead electrode 92 separately, the manufacturing process can be simplified, thereby reducing costs. Of course, the individual lead electrode 91 and the common lead electrode 92 can also be formed from different layers.

[0084] The materials used for the individual lead electrode 91 and the common lead electrode 92 are not particularly limited as long as they are conductive; for example, gold (Au), platinum (Pt), aluminum (Al), copper (Cu), etc., can be used. In this embodiment, gold (Au) is used as both the individual lead electrode 91 and the common lead electrode 92. Furthermore, the individual lead electrode 91 and the common lead electrode 92 may also have a bonding layer that improves the adhesion between them and the first electrode 60, the second electrode 80, or the vibrating plate 50.

[0085] Individual lead electrodes 91 are provided for each active portion 310, that is, for each first electrode 60. The individual lead electrodes 91 are connected via wiring portions 85 to the vicinity of the end 60b of the first electrode 60 in the -X direction, which is provided on the outside of the piezoelectric layer 70, and are led out in the -X direction to the flow channel forming substrate 10, and in fact led out in the -X direction to the vibrating plate 50.

[0086] On the other hand, the common lead electrode 92 is led out from the second electrode 80 constituting the common electrode on the piezoelectric layer 70 to the vibrating plate 50 at both ends in the Y-axis direction in the -X direction. Furthermore, the common lead electrode 92 has an extension portion 93 extending along the Y-axis direction in the region corresponding to the end 12b on the -X direction side of the pressure chamber 12. Moreover, the common lead electrode 92 has an extension portion 94 extending along the Y-axis direction in the region corresponding to the end 12a on the +X direction side of the pressure chamber 12. These extension portions 93 and 94 are continuously provided in the Y-axis direction relative to the plurality of active portions 310. As described above, the common lead electrode 92 is led out to the vibrating plate 50 at both ends in the Y-axis direction in the -X direction.

[0087] Furthermore, the extension portions 93 and 94 extend from the inside of the pressure chamber 12 to the outside of the pressure chamber 12. In this embodiment, the active portion 310 of the piezoelectric actuator 300 extends to the outside of the pressure chamber 12 at both ends in the X-axis direction, and the extension portions 93 and 94 extend from the active portion 310 to the outside of the pressure chamber 12.

[0088] However, in the piezoelectric actuator 300 of this embodiment, when the region farther from the end 80b of the second electrode 80 in the X-axis direction of the second electrode 80 is designated as the first region S1 and the region closer to the end 80b of the second electrode 80 is designated as the second region S2, the piezoelectric layer 70 of the first region S1 is preferentially oriented in the (100) plane, and the (100) plane orientation rate of the piezoelectric layer 70 of the second region S2 is lower than the (100) plane orientation rate of the piezoelectric layer 70 of the first region S1.

[0089] In other words, the piezoelectric layer 70 has a first orientation portion 75 in the first region S1 that performs a preferred orientation of the (100) plane, and a second orientation portion 76 in the second region S2 that has a lower (100) plane orientation rate than the first orientation portion 75.

[0090] The first region S1 and the second region S2 are specifically defined as follows: The first region S1 is the region located within the driving region where the vibrating plate 50 is in contact with the pressure chamber 12, which is a recess. The second region S2 is the region located within the non-driving region where the vibrating plate 50 is not in contact with the pressure chamber 12. That is, the first region S1 is the region inside the pressure chamber 12, preferably the region near the center of the pressure chamber 12 in the X-axis direction, and the second region S2 is the region outside the end 12b of the pressure chamber 12 in the X-axis direction.

[0091] That is, the piezoelectric layer 70 has a first orientation portion 75 with a (100) preferred orientation in the region opposite to the pressure chamber 12, and a second orientation portion 76 with a (100) orientation rate lower than that of the first orientation portion 75 in the region outside the end 12b in the -X direction of the pressure chamber 12. In this embodiment, the piezoelectric layer 70 is mainly composed of the first orientation portion 75 with a (100) preferred orientation, and has a second orientation portion 76 with a (100) orientation rate lower than that of the first orientation portion 75 in a part of the region outside the pressure chamber 12.

[0092] Furthermore, in this specification, "preferred orientation" means that 50% or more, preferably 80% or more of the crystals are oriented on a predetermined crystal plane. For example, "preferred orientation of the (100) plane" includes not only the case where all the crystals are oriented in the (100) plane, but also the case where more than half of the crystals (in other words, 50% or more, preferably 80% or more) are oriented in the (100) plane.

[0093] Furthermore, the second orientation portion 76 only needs to have a lower (100) plane orientation rate compared to the first orientation portion 75. Of course, (100) plane orientation is possible, but (100) plane orientation is not required. In this embodiment, the second orientation portion 76 is preferably oriented in a (111) plane. That is, the piezoelectric layer 70 of the second region S2 is preferably oriented in a (111) plane. In addition, the second orientation portion 76 can also be preferably oriented in a (110) plane. That is, the piezoelectric layer 70 of the second region S2 can also be preferably oriented in a (110) plane.

[0094] Furthermore, although details will be described later, along with the piezoelectric layer 70 having a first orientation portion 75 and a second orientation portion 76, a surface portion 700 with a titanium content different in the first orientation portion 75 and the second orientation portion 76 exists near the surface of the piezoelectric layer 70 on the side of the first electrode 60. That is, the piezoelectric layer 70 has a surface portion 700 with a titanium content different in the first region S1 and the second region S2, at least on the side of the first electrode 60.

[0095] Thus, by having a first orientation portion 75 and a second orientation portion 76 in the piezoelectric layer 70, it is possible to suppress the deformation of the piezoelectric actuator 300 while simultaneously suppressing the heat generation of the piezoelectric layer 70. The first orientation portion 75, which has a preferred orientation in the (100) plane, exhibits a larger piezoelectric strain when a voltage is applied. On the other hand, for example, the second orientation portion 76, which has a preferred orientation in the (111) plane and a lower (100) plane orientation rate compared to the first orientation portion 75, exhibits a smaller piezoelectric strain when a voltage is applied to the piezoelectric actuator 300 than the first orientation portion 75. Therefore, by having a second orientation portion 76 in the region outside the pressure chamber 12 in the piezoelectric layer 70, it is possible to suppress the deformation of the piezoelectric actuator 300 while simultaneously suppressing the heat generation of the piezoelectric layer 70.

[0096] Preferably, the second orientation portion 76 is formed over a large extent on the portion of the active portion 310 of the piezoelectric actuator 300 that is a non-flexible portion, i.e., the portion extending outward toward the pressure chamber 12. This allows for more effective suppression of heat generation in the piezoelectric layer 70.

[0097] Furthermore, preferably, the end portion 76b of the second orientation portion 76 on the -X direction side is located further outward than the end portion 80b of the second electrode 80 on the -X direction side. That is, preferably, the piezoelectric layer 70 of the second region S2, which has a lower orientation rate (100) compared to the piezoelectric layer 70 of the first region S1, extends to the outside of the end portion 80b of the second electrode 80. Moreover, preferably, the end portion 76b of the second orientation portion 76 on the -X direction side is positioned at a point that is somewhat separated from the end portion 80b of the second electrode 80 on the -X direction side.

[0098] The end 80b of the second electrode 80 defines the boundary between the active portion 310, which generates piezoelectric strain when a voltage is applied, and the inactive portion 320, which does not generate piezoelectric strain. Therefore, near the end 80b of the second electrode 80, cracks or the like are easily generated in the piezoelectric layer 70 when a voltage is applied. However, by extending the second orientation portion 76 to a position further outward than the end 80b of the second electrode 80, the piezoelectric strain of the active portion 310 is also reduced. Therefore, the generation of cracks in the piezoelectric layer 70 near the end 80b of the second electrode 80 can be suppressed.

[0099] Of course, as shown in Figure 6, the end portion 76b of the second orientation portion 76 can also be located on the +X direction side compared to the end portion 80b of the second electrode 80. Although in such a structure, the effect of suppressing the generation of cracks in the piezoelectric layer 70 near the end portion 80b of the second electrode 80 may be lower, the effect of suppressing the heating of the piezoelectric layer 70 can be obtained.

[0100] On the other hand, the position of the +X direction side end 76a of the second orientation portion 76 is not particularly limited, but it is preferably near the end 12b of the pressure chamber 12. Furthermore, if it is within a range that ensures the displacement of the piezoelectric actuator 300 due to the applied voltage, the +X direction side end 76a of the second orientation portion 76 can also be located within the pressure chamber 12 as shown in FIG. 7. By maximizing the range of the second orientation portion 76 in this way, the heating of the piezoelectric layer 70 can be further suppressed.

[0101] However, preferably, the end 76a of the second orientation portion 76 on the +X direction side, i.e., the boundary between the first orientation portion 75 and the second orientation portion 76, is located in the region opposite to the extended provisioning portion 93 formed on the second electrode 80. Since the first orientation portion 75 and the second orientation portion 76 exhibit different piezoelectric strains when voltage is applied, cracks are easily generated in the piezoelectric layer 70 near the end 76a of the second orientation portion 76, which serves as the boundary between the first and second orientation portions 75 and 76, when a voltage is applied to the piezoelectric actuator 300. However, if the end 76a of the second orientation portion 76 is located in the region opposite to the extended provisioning portion 93, the displacement of the piezoelectric actuator 300 near the boundary between the first and second orientation portions 75 and 76 is suppressed by the extended provisioning portion 93, thus suppressing the generation of cracks in the piezoelectric layer 70.

[0102] Furthermore, in this embodiment, the portion of the piezoelectric layer 70 located on the outer side compared to the second orientation portion 76, i.e., the -X direction side, becomes the first orientation portion 75. However, the orientation of this portion of the piezoelectric layer 70 is not particularly limited. Since the portion of the piezoelectric layer 70 located on the -X direction side compared to the second orientation portion 76 is an inactive portion 320 where the second electrode 80 is not formed, it will not generate heat when a voltage is applied. Therefore, this portion can of course also be the second orientation portion 76, and the orientation ratio of the (100) plane can also be different from that of the first orientation portion 75 and the second orientation portion 76.

[0103] Next, an example of a method for manufacturing the inkjet recorder 1 according to this embodiment, and in particular an example of a method for manufacturing the piezoelectric actuator 300, will be described. Figures 8 to 19 are cross-sectional views showing the method for manufacturing the inkjet recorder.

[0104] First, as shown in FIG8, an elastic film 51 is formed on the surface of a wafer 110, which serves as a flow channel forming substrate for silicon wafers. In this embodiment, the elastic film 51, made of silicon dioxide, is formed by thermally oxidizing the wafer 110. Of course, the material of the elastic film 51 is not limited to silicon dioxide; it can also be a silicon nitride film, a polycrystalline silicon film, an organic film (polyimide, p-xylyl polymer, etc.). The method for forming the elastic film 51 is not limited to thermal oxidation; it can also be formed by sputtering, CVD (Chemical Vapor Deposition), spin coating, etc.

[0105] Next, as shown in FIG9, an insulating film 52 made of zirconium oxide is formed on the elastic film 51. The insulating film 52 is not limited to zirconium oxide, and titanium oxide (TiO2), aluminum oxide (Al2O3), hafnium oxide (HfO2), magnesium oxide (MgO), lanthanum aluminate (LaAlO3), etc. can also be used. As a method for forming the insulating film 52, sputtering, CVD, vapor deposition, etc. can be listed. Although in this embodiment, the vibrating plate 50 is formed by the elastic film 51 and the insulating film 52, the vibrating plate 50 may also be formed by providing only either the elastic film 51 or the insulating film 52.

[0106] Next, as shown in FIG10, a first electrode 60 is formed on the entire surface of the insulating film 52. While the material of the first electrode 60 is not particularly limited, when lead zirconate titanate (PZT) is used as the piezoelectric layer 70, a material that causes minimal change in conductivity due to lead oxide diffusion is preferred. Therefore, platinum, iridium, or similar materials are preferred as the material for the first electrode 60. Furthermore, the first electrode 60 can be formed, for example, by sputtering or PVD (Physical Vapor Deposition).

[0107] Next, as shown in FIG11, a seed layer 61 made of titanium (Ti) is formed on the first electrode 60 as an orientation control layer. In addition, the seed layer 61 can be formed in either a layered or island-shaped manner.

[0108] At this time, a seed layer 61a corresponding to the first orientation portion 75 and a seed layer 61b forming the second orientation portion 76 are formed with different thicknesses. That is, the seed layer 61a corresponding to the first orientation portion 75 is formed with a preferred orientation of the first orientation portion 75 (100 plane) and has a thickness in the range of about 1 to 200 nm, preferably a predetermined thickness in the range of about 5 to 20 nm. The seed layer 61b forming the second orientation portion 76 is formed with a different thickness than the seed layer 61a.

[0109] In this embodiment where a second orientation portion 76 with preferred orientation on the (111) plane is formed, the seed layer 61 formed on the first electrode 60 is patterned by etching or the like. As shown in FIG12, the seed layer 61b at the location where the second orientation portion 76 is formed is removed, or the thickness of the seed layer 61b at the location where the second orientation portion 76 is formed is made thinner than the thickness of the seed layer 61a at the location where the first orientation portion 75 is formed. In FIG12, the locations where the first orientation portion 75 and the second orientation portion 76 are formed are indicated by imaginary lines. In this embodiment, the seed layer 61b is substantially removed, and the seed layer 61 in other areas, including the seed layer 61a, remains with a predetermined thickness. The etching method for the seed layer 61 is not particularly limited; for example, it can be a method implemented with an etching solution or a dry etching method such as ion polishing.

[0110] In the seed layer 61a formed at a predetermined thickness, when the piezoelectric layer 70 is formed in a subsequent process, the preferred orientation of the piezoelectric layer 70 can be controlled to (100), and as an electromechanical conversion element, a preferred first orientation portion 75 of the piezoelectric layer 70 can be obtained. On the other hand, in the seed layer 61b that has been removed or is left thinly, when the piezoelectric layer 70 is formed in a subsequent process, the piezoelectric layer 70 grows under the influence of the first electrode 60, which serves as the substrate layer. The first electrode 60, which serves as the substrate layer, is made of, for example, platinum and is preferably oriented in a (111) plane. Therefore, the second orientation portion 76 is influenced by the first electrode 60 and is also preferably oriented in a (111) plane.

[0111] Here, the seed layer 61 functions as a seed to promote crystallization during the crystallization of the piezoelectric layer 70, and diffuses within the piezoelectric layer 70 after firing. Therefore, the piezoelectric layer 70 has a surface portion 700 in the vicinity of the surface on the first electrode 60 side, for example, within a range of about 20 nm to 30 nm, where the titanium content differs in the first orientation portion 75 and the second orientation portion 76. That is, the piezoelectric layer 70 has a surface portion 700 on the first electrode 60 side where the titanium content differs in the first region S1 and the second region S2 (see Figure 4).

[0112] Specifically, the titanium content of the surface portion 700b formed in the second orientation portion 76 with a preferred orientation in the (111) plane is lower than the titanium content of the surface portion 700a of the first orientation portion 75 with a preferred orientation in the (100) plane. That is, the titanium content of the surface portion 700b in the second region S2 is lower than the titanium content of the surface portion 700a in the first region S1.

[0113] In other words, the first orientation portion 75 has a surface portion 700a containing a predetermined amount of titanium as a result of the (100) plane preferred orientation, and the second orientation portion 76 has a surface portion 700b having a lower titanium content compared to the surface portion 700a of the first orientation portion 75 as a result of the (111) plane preferred orientation. Furthermore, "lower titanium content" is a relative limitation, and titanium may not necessarily be present in the surface portion 700b of the second orientation portion 76.

[0114] Incidentally, unlike this embodiment, when forming the second orientation portion 76 with preferred orientation on the (110) plane, the thickness of the seed layer 61b at the position corresponding to the second orientation portion 76 is made thicker than the thickness of the seed layer 61a at the position corresponding to the first orientation portion 75. For example, the seed layer 61 formed on the first electrode 60 is patterned by etching or the like, thereby temporarily removing the seed layer 61a at the position corresponding to the first orientation portion 75. Thereafter, a seed layer 61 made of titanium (Ti) is formed again on the first electrode 60 with a predetermined thickness. Thus, the seed layer 61a at the position corresponding to the first orientation portion 75 has an appropriate thickness, and the seed layer 61b at the position opposite to the second orientation portion 76 is thicker than the seed layer 61a.

[0115] Even in this case, in the portion of the seed layer 61a that is provided with a predetermined thickness, when the piezoelectric layer 70 is formed in a subsequent process, the preferred orientation of the piezoelectric layer 70 can be controlled to (100), and as an electromechanical conversion element, a preferred first orientation portion 75 of the piezoelectric layer 70 can be obtained. On the other hand, in the portion of the seed layer 61b that is formed to be thicker than the seed layer 61a, when the piezoelectric layer 70 is formed in a subsequent process, the piezoelectric layer 70 grows freely, thereby the second orientation portion 76 is preferably oriented in the (110) plane.

[0116] Furthermore, in this case, the piezoelectric layer 70 also has a surface portion 700 near the surface on the side of the first electrode 60, where the titanium content differs between the first orientation portion 75 and the second orientation portion 76. Moreover, the titanium content of the surface portion 700b of the second orientation portion 76, which is preferentially oriented in the (110) plane, is higher than the titanium content of the surface portion 700a of the first orientation portion 75. That is, the titanium content of the surface portion 700b in the second region S2 is higher than the titanium content of the surface portion 700b in the first region S1.

[0117] In other words, the first orientation portion 75 has a surface portion 700a containing a predetermined amount of titanium as a result of the (100) plane preferred orientation, and the second orientation portion 76 has a surface portion 700b having a higher titanium content than the surface portion 700a of the first orientation portion 75 as a result of the (110) plane preferred orientation.

[0118] Next, a piezoelectric layer 70 composed of lead zirconate titanate (PZT) is formed. In this embodiment, the piezoelectric layer 70 is formed using a so-called sol-gel method, in which a so-called sol in which a metal complex is dissolved and dispersed in a solvent is coated, dried, and gelled, and then sintered at high temperature to obtain a piezoelectric layer 70 composed of a metal oxide. The method for manufacturing the piezoelectric layer 70 is not limited to the sol-gel method; for example, liquid phase film formation methods such as MOD, or vapor phase film formation methods such as sputtering, physical vapor deposition (PVD), and laser ablation can also be used.

[0119] As a specific step in forming the piezoelectric layer 70, firstly, as shown in FIG13, a piezoelectric precursor film 73, serving as a PZT precursor film, is formed on the first electrode 60 on which the seed layer 61 is formed. That is, a sol (solution) containing a metal complex is coated on the wafer 110 for forming a flow channel substrate on which the first electrode 60 (seed layer 61) is formed (coating process). Next, the piezoelectric precursor film 73 is heated to a predetermined temperature and dried for a fixed time (drying process). For example, in this embodiment, the piezoelectric precursor film 73 can be dried by holding it at 170 to 180°C for 8 to 30 minutes.

[0120] Next, degreasing (degreasing process) is performed by heating the dried piezoelectric precursor film 73 to a predetermined temperature and holding it for a fixed time. For example, in this embodiment, degreasing is performed by heating the piezoelectric precursor film 73 to a temperature of about 300 to 400°C and holding it for about 10 to 30 minutes. Furthermore, degreasing as used here refers to the removal of organic components contained in the piezoelectric precursor film 73, such as NO2, CO2, H2O, etc.

[0121] Next, as shown in FIG14, the piezoelectric precursor film 73 is crystallized by heating it to a predetermined temperature and holding it for a fixed time, thereby forming a piezoelectric film 74 (firing process). In this firing process, it is preferable to heat the piezoelectric precursor film 73 to 700°C or higher. Furthermore, in the firing process, it is preferable to set the heating rate to 50°C / sec or higher. As a result, a piezoelectric film 74 with excellent properties can be obtained.

[0122] Heating devices used in such drying, degreasing, and firing processes include, for example, RTP (Rapid Thermal Processing) devices that can be heated by using hot plates or by irradiation with infrared lamps.

[0123] Next, as shown in FIG15, during the stage of forming a first layer of piezoelectric film 74 on the first electrode 60, patterning is performed on both the first electrode 60 and the first layer of piezoelectric film 74. Furthermore, the patterning of the first electrode 60 and the first layer of piezoelectric film 74 is performed, for example, by dry etching such as ion polishing.

[0124] Here, for example, if a first piezoelectric film 74 is formed after patterning the first electrode 60, the surface of the first electrode 60 deteriorates because the patterning process involves photolithography, ion polishing, and ashing. Therefore, even if a piezoelectric film 74 is formed on the deteriorated surface, its crystallinity will not be good. Since subsequent piezoelectric films 74 also affect the crystallization state and crystallize, a piezoelectric layer 70 with good crystallinity cannot be formed.

[0125] In comparison, if patterning is performed simultaneously with the first electrode 60 after the formation of the first piezoelectric film 74, the first piezoelectric film 74, compared with the first electrode 60, will have stronger properties even as a seed for the good crystal growth of the second and subsequent piezoelectric films 74. Even if an extremely thin modified layer is formed on the surface through patterning, it will not have a significant impact on the crystal growth of the second and subsequent piezoelectric films 74.

[0126] Next, as shown in Figure 16, a piezoelectric film forming process consisting of the above-mentioned coating process, drying process, degreasing process and firing process is repeatedly performed to form a piezoelectric layer 70 consisting of multiple piezoelectric films 74.

[0127] Next, as shown in FIG17, the piezoelectric layer 70 is patterned corresponding to each pressure chamber 12. In this embodiment, the patterning is performed by a so-called photolithography method, in which a mask (not shown) formed in a predetermined shape is provided on the piezoelectric layer 70 and the piezoelectric layer 70 is etched through the mask. Alternatively, the patterning of the piezoelectric layer 70 can be achieved, for example, by dry etching such as reactive ion etching or ion polishing.

[0128] Next, as shown in FIG18, a second electrode 80 made of iridium (Ir) is formed, for example, across the piezoelectric layer 70 and the insulating film 52, and the second electrode 80 is patterned according to a predetermined pattern. Furthermore, as shown in FIG19, individual lead electrodes 91 and common lead electrodes 92 are formed on the wafer 110 for forming the flow channel substrate. Thus, the piezoelectric actuator 300 is formed.

[0129] Although subsequent processes are not illustrated, after the protective substrate wafer, which serves as a silicon wafer and constitutes multiple protective substrates 30, is bonded to the piezoelectric actuator 300 side of the flow channel forming substrate wafer 110, the flow channel forming substrate wafer 110 is thinned to a predetermined thickness. Furthermore, the flow channel forming substrate wafer 110 is anisotropically etched (wet etching) using an alkaline solution such as KOH via a mask patterned in a predetermined shape, thereby forming the pressure chamber 12 divided by the partition wall 11.

[0130] Furthermore, for example, the unwanted portions of the outer peripheral edges of the flow channel forming substrate wafer 110 and the protective substrate wafer are removed by cutting or the like. The junction of the flow channel forming substrate wafer 110 and the protective substrate wafer is divided into a single-chip-sized flow channel forming substrate 10, as shown in FIG1. ​​Moreover, the recording head 1 of this embodiment is manufactured by bonding the connecting plate 15, the nozzle plate 20, the housing component 40, the malleable substrate 45, etc., to the junction of the protective substrate 30 and the flow channel forming substrate 10.

[0131] As explained above, in the inkjet recording head 1 according to this embodiment, the piezoelectric layer 70 in the first region S1 is preferably oriented in a (100) plane, and the (100) plane orientation rate of the piezoelectric layer 70 in the second region S2 is lower than that of the piezoelectric layer 70 in the first region S1. More specifically, in the recording head 1, the piezoelectric layer 70 has a first orientation portion 75 in the first region S1 that is preferably oriented in a (100) plane, and a second orientation portion 76 in the second region S2 that is preferably oriented in a (111) plane. As a result, it is possible to suppress the heating of the piezoelectric layer 70 while suppressing the obstruction of the deformation of the piezoelectric actuator 300.

[0132] Furthermore, in this embodiment, as a step in forming the piezoelectric actuator 300, there is a step in forming an orientation control layer, namely a seed layer 61, for controlling the crystal orientation of the piezoelectric layer 70. In the step of forming the seed layer 61, the seed layer 61 is formed to have different thicknesses in the first region S1 and the second region S2. That is, the seed layer 61 is formed to have different thicknesses in the first orientation portion 75 and the second orientation portion 76. Specifically, as described above, the thickness of the seed layer 61 at the position corresponding to the second orientation portion 76 is thinner than the thickness of the seed layer 61 at the position corresponding to the first orientation portion 75. As a result, the first orientation portion 75 can be preferentially oriented in the (100) plane, and the second orientation portion 76 can be preferentially oriented in the (111) plane.

[0133] However, although in this embodiment it is set that when forming the piezoelectric layer 70, the orientation of the piezoelectric layer 70, namely the orientation of the first orientation portion 75 and the second orientation portion 76, is controlled by adjusting the thickness of the seed layer 61 formed on the first electrode 60 as an orientation control layer, the orientation of the piezoelectric layer 70 can also be controlled by adjusting the thickness of the so-called intermediate seed layer.

[0134] After the piezoelectric film 74 and the first electrode 60 of the first layer are patterned (see FIG15), the intermediate seed layer 62 is formed across the insulating film 52, the side surface of the first electrode 60, the side surface of the piezoelectric film 74 of the first layer, and the piezoelectric film 74, as shown in FIG20. This intermediate seed layer 62, like the seed layer 61, preferably uses titanium and is formed in a layered or island-like shape. Thereafter, in the same manner as the embodiment described above, the second and subsequent piezoelectric films 74 are formed (see FIGS16-19).

[0135] Furthermore, the orientation of the piezoelectric film 74 after the second layer can also be controlled through this intermediate seed layer 62. Similar to the seed layer 61 described above, the thickness of the intermediate seed layer 62b at the position corresponding to the second orientation portion 76 is made thinner than the thickness of the intermediate seed layer 62a at the position corresponding to the first orientation portion 75 (see Figure 20). As a result, the first orientation portion 75 can be preferably oriented in the (100) plane, and the second orientation portion 76 can be preferably oriented in the (111) plane. Moreover, when the intermediate seed layer 62 is formed, a surface portion 700 with a titanium content different in the first orientation portion 75 and the second orientation portion 76 is present near the surface on the first electrode 60 side of the piezoelectric layer 70.

[0136] Alternatively, when forming the intermediate seed layer 62, the seed layer 61 may be omitted or formed together with the intermediate seed layer 62. When forming the seed layer 61 together with the intermediate seed layer 62, it is sufficient that the thickness of the seed layer 61 is generally set to be approximately uniform.

[0137] Implementation Method 2

[0138] Figure 21 is a cross-sectional view of the inkjet recording head according to this embodiment. Furthermore, the same symbols are used to label the same parts, and repeated descriptions are omitted.

[0139] In Embodiment 1 described above, when manufacturing the piezoelectric actuator 300, a seed layer 61 made of titanium is formed as an orientation control layer, resulting in a titanium-containing surface portion 700 in the piezoelectric layer. In this embodiment, since the seed layer 61 is not formed when manufacturing the piezoelectric actuator 300, the titanium-containing surface portion 700 does not exist.

[0140] In the inkjet recording head 1 according to this embodiment, as shown in FIG21, an alignment layer 150 serving as an alignment control layer is provided between the first electrode 60 and the piezoelectric layer 70. This alignment layer 150 is configured to contain materials selected from LaNi. y O x 、SrRu y O x (Ba, Sr)Ti y O x (Bi,Fe)Ti y O x At least one of them, preferably, is made of LaNi y O x constitute.

[0141] Furthermore, in the alignment layer 150, the length in the Z-axis direction of the second region S2 is shorter than the length in the Z-axis direction of the alignment layer 150 in the first region S1. That is, the alignment layer 150 corresponding to the first alignment portion 75 of the piezoelectric layer 70 is formed with a predetermined thickness, and the thickness of the alignment layer 150b at the position corresponding to the second alignment portion 76 is thinner than the thickness of the alignment layer 150a at the position corresponding to the first alignment portion 75.

[0142] By forming a piezoelectric layer 70 on an alignment layer 150 of a predetermined thickness, the preferred orientation of the piezoelectric layer 70 can be controlled to (100), and a preferred piezoelectric layer 70 can be obtained as an electromechanical conversion element. Therefore, a first alignment portion 75 with a (100) plane preferred orientation is formed on the alignment layer 150 of a predetermined thickness. On the other hand, when the piezoelectric layer 70 is formed on an alignment layer 150 that is thinner than the portion corresponding to the first alignment portion 75, it is grown under the influence of a first electrode 60 serving as a substrate layer. The first electrode 60 serving as a substrate layer is made of, for example, platinum, and has a (111) plane preferred orientation. Therefore, a second alignment portion 76 with a (111) plane preferred orientation is formed on an alignment layer 150 that is thinner than the portion corresponding to the first alignment portion 75.

[0143] Furthermore, the alignment layer 150 can be formed using the same steps as the seed layer 61. Specifically, after forming the alignment layer 150 on the entire surface of the first electrode 60, the alignment layer 150 is patterned by etching or the like, and the alignment layer 150b at the position corresponding to the second alignment portion 76 is removed, or the thickness of the alignment layer 150b is made thinner than the thickness of the alignment layer 150 at the position corresponding to the first alignment portion 75. The etching method for the alignment layer 150 is not particularly limited; for example, it can be etching performed with an etchant or dry etching such as ion polishing.

[0144] Furthermore, the alignment layer 150 involved in this embodiment remains as a layer without being diffused into the piezoelectric layer 70. Although the thickness of the alignment layer 150 is not particularly limited, it is preferably about 5 nm to 20 nm. As a result, the first alignment portion 75 can be well oriented in the (100) plane.

[0145] Implementation Method 3

[0146] Figure 22 is a cross-sectional view of an inkjet recording head, which is an example of a liquid jetting head according to Embodiment 3 of the present invention, and is an enlarged view showing the structure of the piezoelectric actuator 300. Furthermore, the same reference numerals are used for the same components as in Embodiment 1, and repeated descriptions are omitted.

[0147] As shown in FIG22, the piezoelectric actuator 300 according to this embodiment includes a protective film 200 disposed on the -Z direction side of the second electrode 80, i.e., on the second electrode 80. The end 80b of the second electrode 80, which is closer to the second region S2, is covered by the protective film 200. That is, the protective film 200 is disposed in such a way that it covers the boundary between the active part 310 and the inactive part 320 of the piezoelectric actuator 300. In addition, the structure other than the protective film 200 is the same as in Embodiment 1.

[0148] In the piezoelectric layer 70 near the boundary between the active portion 310 and the inactive portion 320, stress concentration may occur, for example, due to uneven piezoelectric strain generation. Consequently, cracks or burn-out caused by these cracks may become apparent. However, in this embodiment, since a protective film 200 is provided to cover the boundary portion between the active portion 310 and the inactive portion 320, the generation of cracks and burn-out in this area can be reduced more reliably.

[0149] Although in the example shown in FIG22, the protective film 200 is only provided near the end 80b of the second electrode 80, the range of the protective film 200 is not particularly limited. For example, the protective film 200 may also be provided in a manner that covers the exposed portion of the surface of the piezoelectric layer 70 of the inactive portion 320.

[0150] Furthermore, while the material of the protective film 200 is not particularly limited, organic materials such as polyimide (aromatic polyimide) can be used, for example. Additionally, the protective film 200 can also be formed from epoxy-based adhesives or silicone-based adhesives. Furthermore, when the protective film 200 is formed by an adhesive, it can also be configured such that the adhesive used to bond the protective substrate 30 to the flow channel forming substrate 10 functions as the protective film 200. That is, it can also be configured such that the protective substrate 30 is bonded to the portion of the flow channel forming substrate 10 corresponding to the end 80b of the second electrode 80, and the end 80b of the second electrode 80 is covered by the adhesive.

[0151] Furthermore, preferably, the Young's modulus of the protective film 200 in the second region S2 is lower than that of the second electrode 80. In this embodiment, since the protective film 200 is formed of an organic material such as polyimide, the Young's modulus of the protective film 200 is lower than that of the second electrode 80 formed of a metal such as iridium. As a result, piezoelectric strain in the piezoelectric layer 70 at the boundary between the active portion 310 and the inactive portion 320 is more difficult to occur. In addition, since vibrations are also easily absorbed, the generation of cracks and burn-out in this region can be reduced more reliably.

[0152] Other implementation methods

[0153] The various embodiments of the present invention have been described above, but the basic structure of the present invention is not limited to the embodiments described above.

[0154] For example, although in the above embodiment it is set that the orientation ratio of the second orientation portion 76 is lower than that of the first orientation portion 75 by adjusting the thickness of the seed layer 61, intermediate seed layer 62 or orientation layer 150, which are orientation control layers, the method of adjusting the orientation ratio of the first orientation portion 75 and the second orientation portion 76, that is, the method of adjusting the orientation ratio of the piezoelectric layer 70, is not particularly limited. For example, when the piezoelectric layer 70 is formed, the orientation ratio of the piezoelectric layer 70 can be changed by adjusting the amount of impurities present on the first electrode 60 or the piezoelectric film 74 of the first layer. More specifically, when the first electrode 60 or the piezoelectric film 74 of the first layer is patterned using a mask made of organic material, a very small portion of the mask remains on the portion where the second orientation portion 76 is formed, and the remaining piezoelectric layer 70 is formed in this state. Therefore, the orientation ratio of the second orientation portion 76 (100) can be lower than that of the first orientation portion 75.

[0155] Furthermore, in the above embodiment, the structure near the end 80b in the -Y direction of the second electrode 80 was described as an example to illustrate the present invention, but the present invention can also be applied to the area near the end 80b in the +Y direction of the second electrode 80. In cases where the boundary between the active portion 310 and the inactive portion 320 of the piezoelectric actuator 300, defined by the end 80a of the second electrode 80, exists outside the pressure chamber 12 in the +Y direction, the structure of the present invention described above can also be applied to the end 80a side of the second electrode 80 in the +Y direction.

[0156] Furthermore, although in the various embodiments described above, the first electrode 60 is configured as an independent electrode for each active part 310, and the second electrode 80 is configured as a common electrode for multiple active parts 310, it is also possible to configure the first electrode 60 as a common electrode for multiple active parts 310, and the second electrode 80 as an independent electrode for each active part 310. Even in this case, the same effect as the embodiments described above can be obtained.

[0157] Furthermore, the recording head 1 of these various embodiments is mounted on an inkjet recording device, which is an example of a liquid jetting device. Figure 23 is a schematic diagram showing an example of a liquid jetting device according to one embodiment, namely an example of an inkjet recording device.

[0158] In the inkjet recording device I shown in Figure 23, the recording head 1 is detachably mounted on a cartridge 2 that constitutes the ink supply unit and is mounted on a carriage 3. The carriage 3, on which the recording head 1 is mounted, is configured to move freely in the axial direction of a carriage shaft 5 mounted on the device body 4.

[0159] Furthermore, the driving force of the drive motor 6 is transmitted to the carriage 3 via multiple gears (not shown) and a timing belt 7, thereby causing the carriage 3, which carries the recording head 1, to move along the carriage shaft 5. On the other hand, a conveyor roller 8, which serves as a conveying unit, is provided in the main body 4 of the device, through which the recording sheet S, such as paper, is conveyed. In addition, the conveying unit for conveying the recording sheet S is not limited to a conveyor roller, but may also be a belt or a roller, etc.

[0160] In such an inkjet recording device I, while the recording sheet S is being transported in the +X direction relative to the recording head 1 and the carriage 3 is reciprocating in the Y direction relative to the recording sheet S, ink droplets are ejected from the recording head 1, thereby covering approximately the entire surface of the recording sheet S and performing the so-called printing.

[0161] Furthermore, although the inkjet recording device I described above exemplifies a method in which the recording head 1 is mounted on the carriage 3 and moves back and forth in the Y direction, which is the main scanning direction, it is not particularly limited to this. For example, the present invention can also be applied to a so-called line recording device in which the recording head 1 is fixed so that printing is performed only by moving the recording sheet S, such as paper, in the X direction, which is the secondary scanning direction.

[0162] Furthermore, in the above embodiments, an inkjet recording head was listed as an example of a liquid ejection head, and an inkjet recording device was listed as an example of a liquid ejection device, and these have been described. However, the present invention is a invention that broadly applies to all liquid ejection heads and liquid ejection devices, and of course, it can also be applied to liquid ejection heads or liquid ejection devices that eject liquids other than ink. Other liquid ejection heads include, for example, various recording heads used in image recording devices such as printers, color material ejection heads used in the manufacture of color filters for liquid crystal displays, electrode material ejection heads used in electrode formation for organic EL (Electroluminescence) displays, FED (Field Emission Displays), etc., and biological organic matter ejection heads used in the manufacture of biochips, etc., and can also be applied to liquid ejection devices equipped with the liquid ejection heads mentioned above.

[0163] Furthermore, this invention can be applied not only to liquid jetting heads, such as inkjet recording heads, but also to other piezoelectric devices such as ultrasonic transmitters, ultrasonic motors, pressure sensors, and thermoelectric sensors.

[0164] Symbol Explanation

[0165] S1…First region; S2…Second region; I…Inkjet recording device (recording device); 1…Inkjet recording head (recording head); 2…Case; 3…Carriage; 4…Main body; 5…Carriage shaft; 6…Drive motor; 7…Synchronous belt; 8…Conveyor roller; 10…Flow channel forming substrate (substrate); 11…Block; 12…Pressure chamber (recess); 15…Connecting plate; 16…Nozzle connecting channel; 17…First manifold; 18…Second manifold; 19…Supply connecting channel; 20…Nozzle plate; 21…Nozzle; 30…Protective substrate; 31…Holding part; 32…Through hole; 40…Outer shell component; 41…Storage part; 42…Third manifold; 43…Connecting port; 44…Inlet; 45…Moldable substrate; 46…Sealing film; 47…Fixing base 48…plate; 49…opening; 50…plastic section; 51…vibrating plate; 52…elastic membrane; 60…insulating membrane; 61…first electrode; 62…seed layer; 70…intermediate seed layer; 71…groove; 75…first orientation section; 76…second orientation section; 80…second electrode; 81…first layer; 82…second layer; 83…third layer; 85…wiring section; 91…independent lead electrode; 92…common lead electrode; 93…extension setting section (third electrode); 94…extension setting section; 100…manifold; 120…wiring substrate; 121…drive circuit; 150…orientation layer; 200…protective film; 300…piezoelectric actuator; 310…active section; 320…inactive section; 700…surface layer; S…recording film.

Claims

1. A piezoelectric device, characterized in that, The device comprises: a substrate having a plurality of recesses; a vibrating plate disposed on one side of the substrate; and a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on the side of the vibrating plate opposite to the substrate, wherein when a region farther from the end of the second electrode is designated as the first region and a region closer to the end of the second electrode is designated as the second region, the piezoelectric layer in the first region is preferably oriented in a (100) plane, and the (100) plane orientation rate of the piezoelectric layer in the second region is lower than that of the piezoelectric layer in the first region. (100) Surface orientation rate, the first region is located in the driving region where the vibrating plate is in contact with the recess and the non-driving region where the vibrating plate is not in contact with the recess, the second region is located in the non-driving region, the boundary between the first region and the second region in the second direction is located in the non-driving region, the piezoelectric actuator has a third electrode that is stacked on the second electrode in the first direction in such a way as to cover a part of the second electrode and extends upward in a third direction intersecting the first direction and the second direction, the boundary between the first region and the second region in the second direction is located in the region where the third electrode is provided in the second direction.

2. The piezoelectric device as described in claim 1, characterized in that, Between the first electrode and the piezoelectric layer, a layer containing materials selected from LaNi is disposed. y O x 、SrRu y O x (Ba, Sr)Ti y O x (Bi,Fe)Ti y O x At least one of the orientation control layers, wherein the length of the first direction of the orientation control layer in the second region is shorter than the length of the first direction of the orientation control layer in the first region.

3. The piezoelectric device as described in claim 2, characterized in that, The orientation control layer is made of LaNi y O x constitute.

4. The piezoelectric device as described in claim 1, characterized in that, The piezoelectric layer has a surface portion on the first electrode side where the titanium content differs between the first region and the second region.

5. The piezoelectric device as described in claim 4, characterized in that, The titanium content of the surface layer in the second region is higher than that of the surface layer in the first region.

6. The piezoelectric device as described in claim 5, characterized in that, The piezoelectric layer in the second region is preferably oriented in the (110) plane.

7. The piezoelectric device as described in claim 4, characterized in that, The titanium content of the surface layer in the second region is lower than that of the surface layer in the first region.

8. The piezoelectric device as described in claim 7, characterized in that, The piezoelectric layer in the second region is preferably oriented in a (111) plane.

9. The piezoelectric device as claimed in claim 1, characterized in that, The piezoelectric layer in the second region extends to the outer side of the end of the second electrode.

10. The piezoelectric device as claimed in claim 1, characterized in that, It has a protective film that covers the end of the second electrode that is closer to the second region.

11. A liquid injection head, characterized in that, The device comprises: a substrate having a plurality of recesses; a vibrating plate disposed on one side of the substrate; and a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on the side of the vibrating plate opposite to the substrate, wherein when a region farther from the end of the second electrode is designated as the first region and a region closer to the end of the second electrode is designated as the second region, the piezoelectric layer in the first region is preferably oriented in a (100) plane, and the (100) plane orientation rate of the piezoelectric layer in the second region is lower than that of the piezoelectric layer in the first region. (100) Surface orientation rate, the first region is located in the driving region where the vibrating plate is in contact with the recess and the non-driving region where the vibrating plate is not in contact with the recess, the second region is located in the non-driving region, the boundary between the first region and the second region in the second direction is located in the non-driving region, the piezoelectric actuator has a third electrode that is stacked on the second electrode in the first direction in such a way as to cover a part of the second electrode and extends upward in a third direction intersecting the first direction and the second direction, the boundary between the first region and the second region in the second direction is located in the region where the third electrode is provided in the second direction.

12. A liquid injection device, characterized in that, It has the liquid injection head as described in claim 11.

13. A method for manufacturing a piezoelectric device, characterized in that, The piezoelectric device comprises: a substrate having a plurality of recesses; a vibrating plate disposed on one side of the substrate; and a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on the side of the vibrating plate opposite to the substrate. When a region farther from the end of the second electrode is designated as the first region, and a region closer to the end of the second electrode is designated as the second region, the piezoelectric layer in the first region is preferably oriented in a (100) plane, and the (100) plane orientation rate of the piezoelectric layer in the second region is lower than that of the piezoelectric layer in the first region. The first region is located in a driving region where the vibrating plate is in contact with the recesses and in a non-driving region where the vibrating plate is not in contact with the recesses. The second region is located in the non-driving region. The boundary between the first region and the second region in the two directions is located within the non-driving region. The piezoelectric actuator has a third electrode stacked on the second electrode in the first direction in such a way as to cover a portion of the second electrode and extending upward in a third direction intersecting the first and second directions. The boundary between the first region and the second region in the second direction is located within the region where the third electrode is disposed in the second direction. In the manufacturing method of the piezoelectric device, as a step of forming the piezoelectric actuator by stacking the first electrode, the piezoelectric layer and the second electrode on the surface of the vibrating plate disposed on the substrate, there is a step of forming an orientation control layer for controlling the crystal orientation of the piezoelectric layer. In the step of forming the orientation control layer, the orientation control layer is formed to have different thicknesses in the first region and the second region.

14. The method for manufacturing a piezoelectric device as described in claim 13, characterized in that, In the process of forming the orientation control layer, after forming the orientation control layer in a region including the first region and the second region on the surface of the first electrode, at least a portion of the orientation control layer in the second region is removed, so that the thickness of the orientation control layer in the second region is thinner than the thickness of the orientation control layer in the first region.

15. The method for manufacturing a piezoelectric device as described in claim 13, characterized in that, In the process of forming the orientation control layer, the orientation control layer is formed in a region on the surface of the first electrode that includes the first region and the second region. After removing at least a portion of the orientation control layer in the first region to make it thinner than the orientation control layer in the second region, the orientation control layer is formed again in a region on the surface of the first electrode that includes the first region and the second region, such that the orientation control layer in the second region is thicker than the orientation control layer in the first region.

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