Piezoelectric device, liquid ejecting head, and liquid ejecting apparatus

Abstract

A piezoelectric device, a liquid ejecting head, and a liquid ejecting apparatus are provided, which suppress generation of a crack or a burnout or the like of a piezoelectric layer in the vicinity of an end portion of a second electrode. The liquid ejecting head includes a vibration plate provided on one face side of a substrate and a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on a face side of the vibration plate opposite to the substrate. When one region of two regions of the second electrode in a second direction intersecting the first direction, which is farther from an end portion of the second electrode, is set as a first region and one region closer to the end portion of the second electrode is set as a second region, the second electrode is formed such that rigidity in the first direction in the second region is 17000 N / m or more and higher than rigidity in the first direction in the first region, and a length in the first direction in the second region is equal to or less than a length in the first direction of the piezoelectric layer in the second region.

Description

TECHNICAL FIELD

[0001] The present application relates to a piezoelectric device, a liquid ejection head, and a liquid ejection apparatus, the piezoelectric device including a vibrating plate and a piezoelectric actuator including a first electrode, a piezoelectric layer, and a second electrode. BACKGROUND

[0002] As a representative example of the liquid ejection head as one of the piezoelectric devices, an inkjet recording head that ejects ink droplets can be cited. As the inkjet recording head, there is known an inkjet recording head including a flow passage forming substrate in which a pressure chamber communicating with, for example, a nozzle is formed, and a piezoelectric actuator provided on one face side of the flow passage forming substrate via a vibrating plate, and ink in the pressure chamber is caused to generate a pressure change by the piezoelectric actuator, whereby ink droplets are ejected from the nozzle.

[0003] Further, as the piezoelectric actuator, there is known a piezoelectric actuator including a first electrode formed on a vibrating plate, a piezoelectric layer formed on the first electrode by a piezoelectric material having an electromechanical conversion characteristic, and a second electrode provided on the piezoelectric layer. In the piezoelectric actuator of this structure, it is possible that a crack or a burn, or the like, is generated in the piezoelectric layer due to a flexural deformation of the piezoelectric layer. In order to suppress generation of such an undesirable phenomenon, various structures of the piezoelectric actuator have been proposed (for example, refer to Patent Literature 1).

[0004] In Patent Literature 1, there is disclosed a structure in which the piezoelectric element is extended to a position outside the opening edge of the pressure chamber from a position corresponding to the opening portion of the pressure chamber, and the piezoelectric layer has an exposed portion in which the second electrode is removed in a portion of the piezoelectric layer extended to the position outside the pressure chamber, and the exposed portion of the piezoelectric layer is covered with an adhesive.

[0005] By being provided with such a structure, it is possible to suppress generation of a crack or a burn, or the like, with respect to the piezoelectric layer.

[0006] However, even if provided with the above structure, it is difficult to completely suppress generation of a crack or a burn, or the like, with respect to the piezoelectric layer in the vicinity of the end portion of the second electrode extended to the outside of the pressure chamber. Although in the region in which the piezoelectric layer is hindered from flexural deformation by being extended to the outside of the pressure chamber, a strain is generated at an active portion in which the second electrode overlaps in the piezoelectric layer to which a voltage is applied, but no strain is generated in an inactive portion in which the second electrode does not overlap.

[0007] Therefore, in the boundary portion between the active portion and the inactive portion of the piezoelectric layer, that is, in the vicinity of the end portion of the second electrode, a crack or a burn, or the like is likely to occur. In particular, when a driving pulse supplied to the piezoelectric layer from the electrode becomes high frequency, since the strain action of the active portion becomes high frequency, a crack or a burn, or the like is likely to occur in the above-described boundary portion.

[0008] In addition, such a problem is not limited to a liquid ejecting head typified by an inkjet recording head, but also occurs in other piezoelectric devices.

[0009] Patent Document 1: Japanese Patent Application Publication No. 2017-074798 SUMMARY

[0010] One embodiment of the present application for solving the above-described problem is a piezoelectric device characterized by including: a substrate formed with a plurality of recesses; a vibration plate provided on one face 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 a face side of the vibration plate opposite to the substrate, wherein when one region of two regions in a second direction intersecting the first direction of the second electrode farther from an end portion of the second electrode is set as a first region and one region closer to the end portion of the second electrode is set as a second region, the second electrode is formed such that rigidity in the first direction in the second region is 17000 N / m or more and higher than rigidity in the first direction in the first region, and a length in the first direction in the second region is equal to or less than a length in the first direction of the piezoelectric layer in the second region.

[0011] Another embodiment of the present application is a liquid ejecting head characterized by including: a substrate formed with a plurality of recesses; a vibration plate provided on one face 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 a face side of the vibration plate opposite to the substrate, wherein when one region of two regions in a second direction intersecting the first direction of the second electrode farther from an end portion of the second electrode is set as a first region and one region closer to the end portion of the second electrode is set as a second region, the second electrode is formed such that rigidity in the first direction in the second region is 17000 N / m or more and higher than rigidity in the first direction in the first region, and a length in the first direction in the second region is equal to or less than a length in the first direction of the piezoelectric layer in the second region.

[0012] Further, another embodiment of the present application is a liquid ejecting apparatus including the above-described liquid ejecting head. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 Exploded perspective view of the recording head according to Embodiment 1.

[0014] Figure 2 Plan view of the recording head according to Embodiment 1.

[0015] Figure 3 Cross-sectional view of the recording head according to Embodiment 1.

[0016] Figure 4 Main part cross-sectional view of the recording head according to Embodiment 1.

[0017] Figure 5 Cross-sectional view of the recording head according to Embodiment 1.

[0018] Figure 6 Main part cross-sectional view of the second electrode according to Embodiment 1.

[0019] Figure 7 Graph showing the relationship between rigidity and breakdown voltage of the second electrode and process defect rate.

[0020] Figure 8 Main part cross-sectional view of the recording head according to Embodiment 2.

[0021] Figure 9 Diagram showing the schematic structure of the recording apparatus according to one embodiment. DETAILED DESCRIPTION

[0022] Hereinafter, the present application will be described in detail based on embodiments. However, the following description is a description of one embodiment of the present application, and the structure of the present application can be arbitrarily changed within the scope of the application. In each drawing, the same reference numerals are assigned to the same components, and repeated description is omitted.

[0023] Further, in each drawing, X, Y, and Z represent three spatial axes orthogonal to each other. In the present specification, the directions along these axes are set as the X direction, the Y direction, and the Z direction. The direction toward which the arrow mark of each drawing is set as the positive (+) direction, and the opposite direction of the arrow mark is set as the negative (-) direction, and is described. Further, the Z direction represents the vertical direction, the +Z direction represents the vertically downward direction, and the -Z direction represents the vertically upward direction. Also, regarding the three X, Y, and Z spatial axes which are not defined as the positive direction and the negative direction, the X axis, the Y axis, and the Z axis are described.

[0024] Embodiment 1

[0025] Figure 1Fig. 1 is an exploded perspective view of an example of a liquid ejecting head according to Embodiment 1 of the present application, that is, an inkjet recording head. Figure 2 Fig. 2 is a plan view of the recording head. Figure 3 Fig. 3 is a plan view of the recording head. Figure 2 Fig. 4 is an A-A' line sectional view of the recording head. Figure 4 Fig. 5 is an enlarged view of a piezoelectric actuator portion in Fig. 4. Figure 3 Fig. 6 is an enlarged view of a piezoelectric actuator portion in Fig. 4. Figure 5 Fig. 7 is a B-B' line sectional view of the recording head. Figure 2 Fig. 8 is an enlarged view of a piezoelectric actuator portion in Fig. 7. Figure 6 Fig. 9 is an enlarged sectional view of a main portion of a second electrode.

[0026] As shown in the drawing, an example of a liquid ejecting head according to Embodiment 1 of the present application, that is, an inkjet recording head (hereinafter, also simply referred to as a recording head) 1 is a recording head that ejects ink droplets in a Z-axis direction as a first direction, more specifically, in a +Z direction.

[0027] As an example of a substrate, the inkjet recording head 1 is provided with a flow path forming substrate 10. The flow path forming substrate 10 is constituted of, for example, a silicon substrate, a glass substrate, an SOI (Silicon-On-Insulator) substrate, various ceramic substrates, or the like. In addition, the flow path forming substrate 10 can be either a substrate having a (100) plane as a preferred orientation or a substrate having a (110) plane as a preferred orientation.

[0028] In the flow path forming substrate 10, a plurality of pressure chambers 12 are arranged in two rows in an X-axis direction as a second direction intersecting the first direction, that is, the Z-axis direction. That is, the plurality of pressure chambers 12 constituting each row are arranged along a Y-axis direction as a third direction intersecting the X-axis direction.

[0029] The plurality of pressure chambers 12 constituting each row are arranged on a straight line along the Y-axis direction in such a manner that the positions in the X-axis direction become the same positions. The pressure chambers 12 adjacent to each other in the Y-axis direction are divided by a partition wall 11. Of course, the arrangement of the pressure chambers 12 is not particularly limited. For example, the arrangement of the plurality of pressure chambers 12 arranged side by side in the Y-axis direction can be such that each pressure chamber 12 is arranged at a position offset in the X-axis direction in every other manner, that is, a so-called staggered arrangement.

[0030] Further, the pressure chamber 12 of the present embodiment is longer in the X-axis direction than in the Y-axis direction when viewed from the +Z-direction plane, and is formed, for example, in a rectangular shape. Of course, the shape of the pressure chamber 12 when viewed from the +Z-direction plane is not particularly limited, and can be a parallelogram shape, a polygonal shape, a circular shape, an oblong shape, or the like. Further, the oblong shape referred to herein means a shape in which both ends in the length direction are semicircular shapes based on a rectangular shape, and includes a rounded rectangular shape, an elliptical shape, an egg shape, and the like.

[0031] On the +Z-direction side of the flow channel forming substrate 10, the communication plate 15, the nozzle plate 20, and the plastic substrate 45 are stacked in this order.

[0032] In the communication plate 15, a nozzle communication passage 16 that communicates the pressure chamber 12 and the nozzle 21 is provided. Further, in the communication plate 15, a first manifold portion 17 and a second manifold portion 18 that constitute a part of a manifold 100 that becomes a common liquid chamber to which a plurality of pressure chambers 12 are communicated are provided. The first manifold portion 17 is provided so as to penetrate the communication plate 15 in the Z-axis direction. Further, the second manifold portion 18 is provided so as to be open on the +Z-direction side face without penetrating the communication plate 15 in the Z-axis direction.

[0033] Further, in the communication plate 15, a supply communication passage 19 that communicates with one end portion of the pressure chamber 12 in the X-axis direction is independently provided in each of the pressure chambers 12. The supply communication passage 19 communicates the second manifold portion 18 and each of the pressure chambers 12, and thereby supplies ink in the manifold 100 to each of the pressure chambers 12.

[0034] As the communication plate 15, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate, or the like can be used. As the metal substrate, for example, a stainless steel substrate or the like can be listed. Further, it is preferable that the communication plate 15 use a material having a thermal expansion coefficient substantially the same as that of the flow channel forming substrate 10. Thereby, when the temperature of the flow channel forming substrate 10 and the communication plate 15 changes, warping of the flow channel forming substrate 10 and the communication plate 15 due to a difference in thermal expansion coefficient can be suppressed.

[0035] The nozzle plate 20 is provided on the +Z-direction side face of the communication plate 15 opposite the flow channel forming substrate 10. In the nozzle plate 20, the nozzle 21 that communicates with each of the pressure chambers 12 via the nozzle communication passage 16 is formed.

[0036] In the present embodiment, the plurality of nozzles 21 are arranged side by side in a manner that they are aligned along the Y-axis direction. Also, on the nozzle plate 20, the nozzle rows in which the plurality of nozzles 21 are arranged in rows are provided in two rows in the X-axis direction. That is, the plurality of nozzles 21 of each row are arranged in a manner that the positions in the X-axis direction become the same position. Note that the arrangement of the nozzles 21 is not particularly limited. For example, the nozzles 21 arranged side by side in the Y-axis direction can also be arranged at positions staggered in the X-axis direction at every other position.

[0037] As the material of the nozzle plate 20, there is no particular limitation, and for example, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate can be used. As the metal substrate, for example, a stainless steel substrate or the like can be cited. Also, as the material of the nozzle plate 20, an organic substance such as a polyimide resin or the like can also be used. Among them, it is preferable that the nozzle plate 20 use a material having substantially the same coefficient of thermal expansion as that of the communication plate 15. Thereby, when the temperature of the nozzle plate 20 and the communication plate 15 changes, the warping of the nozzle plate 20 and the communication plate 15 due to the difference in the coefficient of thermal expansion can be suppressed.

[0038] The plastic substrate 45 is provided on the side of the communication plate 15 opposite to the flow channel forming substrate 10, that is, the +Z direction side, together with the nozzle plate 20. This plastic substrate 45 is provided around the nozzle plate 20 and seals the openings of the first manifold portion 17 and the second manifold portion 18 provided in the communication plate 15. In the present embodiment, the plastic substrate 45 has a sealing film 46 composed of a thin film having flexibility and a fixed substrate 47 composed of a hard material such as metal. The region of the fixed substrate 47 opposite to the manifold 100 becomes an opening portion 48 completely removed in the thickness direction. Therefore, one face of the manifold 100 becomes a plastic portion 49 sealed only by the sealing film 46 having flexibility.

[0039] On the other hand, although the details will be described later, on the side of the flow channel forming substrate 10 opposite to the nozzle plate 20 or the like, that is, the -Z direction side, a vibration plate 50 and a piezoelectric actuator 300 are provided, which causes the vibration plate 50 to be flexibly deformed, thereby causing the ink in the pressure chamber 12 to change in pressure. Note that, Figure 3 This is a view for explaining the overall structure of the recording head 1, and the structure of the piezoelectric actuator 300 is simplified.

[0040] On the -Z direction side surface of the flow channel forming substrate 10, a protection substrate 30 having substantially the same size as the flow channel forming substrate 10 is further joined by an adhesive or the like. The protection substrate 30 has a holding portion 31 that is a space for protecting the piezoelectric actuators 300. The holding portion 31 is independently provided for each column of the piezoelectric actuators 300 arranged side by side in the Y axis direction, and is formed side by side in two in the X axis direction. Further, in the protection substrate 30, a through hole 32 is provided that penetrates between the two holding portions 31 arranged side by side in the X axis direction in the Z axis direction.

[0041] Further, on the protection substrate 30, a housing member 40 that divides a manifold 100 that communicates with the plurality of pressure chambers 12 together with the flow channel forming substrate 10 is fixed. The housing member 40 has substantially the same shape as the above-described communication plate 15 when viewed in plan, and is joined to the protection substrate 30 as well as the above-described communication plate 15.

[0042] Such a housing member 40 has a housing portion 41 that is a space capable of housing the flow channel forming substrate 10 and the protection substrate 30 in terms of depth on the protection substrate 30 side. The housing portion 41 has a larger opening area than the surface of the protection substrate 30 that is joined to the flow channel forming substrate 10. Further, in a state in which the flow channel forming substrate 10 and the protection substrate 30 are housed in the housing portion 41, the nozzle plate 20 side opening surface of the housing portion 41 is sealed by the communication plate 15.

[0043] Further, in the housing member 40, a third manifold portion 42 is divided on both outer sides of the housing portion 41 in the X axis direction. Further, the manifold 100 of the present embodiment is constituted by the first manifold portion 17 and the second manifold portion 18 provided in the communication plate 15, and the third manifold portion 42. The manifold 100 is continuously provided in the Y axis direction, and the supply communication passages 19 that communicate each pressure chamber 12 and the manifold 100 are arranged side by side in the Y axis direction.

[0044] Further, in the housing member 40, an inlet port 44 for communicating with the manifold 100 to supply ink to each manifold 100 is provided. Further, in the housing member 40, a connection port 43 is provided that communicates with the through hole 32 of the protection substrate 30 and is inserted through by a wiring substrate 120.

[0045] 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.

[0046] 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.

[0047] like Figure 4 to Figure 6 As shown, 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.

[0048] 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.

[0049] 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.

[0050] A portion of the piezoelectric actuator 300 in which a piezoelectric strain is generated in the piezoelectric layer 70 when a voltage is applied between the first electrode 60 and the second electrode 80 is referred to as an active portion 310. In contrast, a portion in which a piezoelectric strain is not generated in the piezoelectric layer 70 is referred to as an inactive portion 320. That is, the portion of the piezoelectric actuator 300 in which the piezoelectric layer 70 is sandwiched by the first electrode 60 and the second electrode 80 is the active portion 310, and the portion of the piezoelectric layer 70 in which the piezoelectric layer 70 is not sandwiched by the first electrode 60 and the second electrode 80 is the inactive portion 320. Further, when the piezoelectric actuator 300 is caused to drive, the portion that actually displaces in the Z-axis direction is referred to as a flexible portion, and the portion that does not displace in the Z direction is referred to as an inflexible portion. That is, the portion of the piezoelectric actuator 300 that opposes the pressure chamber 12 in the Z-axis direction becomes the flexible portion, and the portion outside the pressure chamber 12 becomes the inflexible portion.

[0051] In general, the electrode of either side of the active portion 310 is provided as an independent electrode that is independent for each active portion 310, and the electrode of the other side is provided as a common electrode that is common to a plurality of active portions 310, and thus is configured. In the present embodiment, the first electrode 60 configures the independent electrode, and the second electrode 80 configures the common electrode.

[0052] Specifically, the first electrode 60 is divided for each pressure chamber 12, and thus configures the independent electrode that is independent for each active portion 310. The first electrode 60 is formed in the Y-axis direction with a width that is narrower than the width of the pressure chamber 12. That is, in the Y-axis direction, the end portion of the first electrode 60 is positioned inside the region that opposes the pressure chamber 12.

[0053] Further, the +X-direction end portion 60a and the -X-direction end portion 60b of the first electrode 60 are respectively disposed outside the pressure chamber 12. As shown in FIG. 6, the +X-direction end portion 60a of the first electrode 60 is disposed at a position that is closer to the +X direction than the +X-direction end portion 12a of the pressure chamber 12. The -X-direction end portion 60b of the first electrode 60 is disposed at a position that is closer to the -X direction than the -X-direction end portion 12b of the pressure chamber 12. Figure 4

[0054] Although the material of the first electrode 60 is not particularly limited, for example, a metal such as iridium or platinum, a conductive metal oxide such as indium tin oxide abbreviated as ITO, or the like is used as a conductive material.

[0055] ​The piezoelectric layer 70 is composed of a piezoelectric material having a polarization structure of an oxide formed on the first electrode 60. For example, it can be composed of a perovskite-type oxide represented by the general formula ABO3. The perovskite-type oxide used as the piezoelectric layer 70 can be, for example, a lead-based piezoelectric material containing lead or a lead-free non-lead piezoelectric material. Furthermore, although the thickness of the piezoelectric layer 70 is not particularly limited, it is acceptable as long as it is formed to be approximately 1 to 4 μm.

[0056] In addition, such as Figure 2 As shown, 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. Furthermore, as... Figure 4 As shown, the length of the piezoelectric layer 70 in the X-axis direction is longer than the length in the X-axis 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.

[0057] In addition, such as Figure 4 As shown, 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.

[0058] In addition, such as Figure 2 as well as Figure 5 As shown, 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.

[0059] 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.

[0060] 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 is not limited to a rectangular shape when viewed from the -Z side plane; it can be a polygon with more than one pentagon, or it can be a circular or elliptical shape, etc.

[0061] 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.

[0062] like Figure 4 as well as Figure 5 As shown, 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. In addition, 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 to cover the entire inner surface of the groove portion 71.

[0063] In addition, such as Figure 4 As shown, 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 also 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.

[0064] 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.

[0065] Thus, since the end portion 80b of the second electrode 80 in the -X direction is disposed on the +X direction side compared to the end portion in the -X direction of the piezoelectric layer 70 and the first electrode 60, the end portion in the -X direction of the active portion 310, that is, the boundary of the active portion 310 and the inactive portion 320 is defined by the end portion 80b of the second electrode 80.

[0066] Here, since the boundary of the active portion 310 and the inactive portion 320 is defined by the end portion 80b of the second electrode 80, in the portion of the surface of the piezoelectric layer 70 exposed in the inactive portion 320, a crack or a burn such as a bad phenomenon is likely to occur in the piezoelectric layer 70.

[0067] Further, in the present application, when one of the two regions in the X axis direction of the second electrode 80, which is farther from the end portion of the second electrode 80, is set as a first region S1, and one which is closer to the end portion of the second electrode 80 is set as a second region S2, the second electrode 80 is formed such that the rigidity in the Z axis direction in the second region S2 is 17000 N / m or more, and is higher than the rigidity in the Z axis direction in the first region S1, and the length in the Z axis direction in the second region S2 becomes the length in the Z axis direction of the piezoelectric layer 70 in the second region S2 or less.

[0068] The first region S1 and the second region S2 are specifically as follows. The first region S1 is a region located in the driving region of the diaphragm 50 which is in contact with the pressure chamber 12 as a recessed portion. The second region S2 is a region located in the non-driving region of the diaphragm 50 which is not in contact with the pressure chamber 12. That is, the first region S1 is a region on the inner side of the pressure chamber 12, and preferably, a region near the central portion of the pressure chamber 12 in the X axis direction, and the second region S2 is a region on the outer side of the end portion 12b in the -X direction of the pressure chamber 12, and preferably, a region near the end portion 80b of the second electrode 80. It is also provided that the end portion 80b of the second electrode 80 is included in the second region S2.

[0069] In the present embodiment, the rigidity in the Z axis direction in the second region S2 in the vicinity of the end portion 80b in the -X direction of the second electrode 80 is made higher than the rigidity in the Z axis direction in the first region S1 which is a region near the central portion of the pressure chamber 12. By being provided with such a structure, the rigidity in the Z axis direction in the second region S2 of the second electrode 80 is locally increased to be a predetermined value or more, and thus the generation of a bad phenomenon of the piezoelectric layer 70 is suppressed without hindering the displacement of the piezoelectric actuator 300.

[0070] As Figure 4 and Figure 6As shown, the second electrode 80 in the first region S1 has the first layer 81 which is continuous in the Z-axis direction with respect to the piezoelectric layer 70. Further, the second electrode 80 in the second region S2 has the first layer 81 which is provided so as to extend from the first region S1, and the second layer 82 which is provided so as to be continuous in the Z direction with respect to the first layer 81 and has a lower electric conductivity than the first layer 81. Further, the second electrode 80 in the second region S2 also has the third layer 83 which is provided so as to be continuous in the Z direction with respect to the second layer 82 and has a higher electric conductivity than the second layer 82. The third layer 83 is not only provided in the second region S2 but also provided so as to extend over the entire first layer 81, and the second electrode 80 in the first region S1 is composed of the first layer 81 and the third layer 83. Therefore, the thickness tl of the second electrode 80 in the second region S2 is thicker than the thickness t2 of the second electrode 80 in the first region S1.

[0071] Although the material of the first layer 81 and the third layer 83 is not particularly limited, like the first electrode 60, for example, a metal such as iridium or platinum, a conductive metal oxide such as indium tin oxide, or the like is preferably used as a conductive material. Further, although the material of the second layer 82 is only required to have a lower electric conductivity than the first layer 81, it is preferably an insulator. As a specific example, titanium oxide abbreviated as TiO X , tantalum oxide abbreviated as TaO X , aluminum oxide abbreviated as AlO X , zirconium oxide abbreviated as ZrO X , silicon oxide abbreviated as SiO X , or the like can be listed.

[0072] Further, in the second electrode 80, as described above, since the thickness tl of the second electrode 80 in the second region S2 is thicker than the thickness t2 of the second electrode 80 in the first region S1, the rigidity in the Z-axis direction of the second electrode 80 in the second region S2 is higher than the rigidity in the Z-axis direction of the second electrode 80 in the first region S1.

[0073] Further, by composing the second electrode 80 in the second region S2 of the first layer 81, the second layer 82, and the third layer 83, the rigidity in the Z-axis direction in the second region S2 is made to be 17000 N / m or more, and the length in the Z-axis direction in the second region S2 is made to be the length in the Z-axis direction of the piezoelectric layer 70 in the second region S2 or less.

[0074] Thus, when the piezoelectric actuator 300 is driven, the strain of the piezoelectric layer 70 in the vicinity of the end portion 80b of the second electrode 80 is suppressed. That is, the strain of the piezoelectric layer 70 in the vicinity of the boundary between the active portion 310 and the inactive portion 320 is suppressed. Although the strain is generated in the active portion 310 on the outside of the pressure chamber 12 when a voltage is applied to the piezoelectric actuator 300, by making the second electrode 80 in the second region S2 have the above-described structure, the strain generated in the active portion 310 is suppressed.

[0075] Therefore, it is possible to suppress undesirable phenomena such as cracks or burn-out of the piezoelectric layer 70 near the boundary between the active portion 310 and the inactive portion 320 of the piezoelectric actuator 300. In particular, the second electrode 80 in the second region S2 is configured to contain TiO₂... X The second layer 82, formed by an insulator, allows the second electrode 80 to function more effectively as a structure that reinforces the piezoelectric layer 70. Therefore, it is possible to more reliably suppress undesirable phenomena near the boundary between the active and inactive portions of the piezoelectric actuator 300.

[0076] The rigidity of the second electrode 80 in the second region S2 in the Z-axis direction only needs to be 17000 N / m or more as described above, and is more preferably 22000 N / m or more. By making the rigidity of the second electrode 80 in the second region S2 in the Z-axis direction 22000 N / m or more, the strain of the active part 310 is further suppressed within an appropriate range. Therefore, it is possible to further reliably suppress undesirable phenomena such as cracks relative to the piezoelectric layer 70.

[0077] Furthermore, the length of the second electrode 80 in the Z-axis direction in the second region S2 is shorter than the length of the piezoelectric layer 70 in the Z-axis direction in the second region S2. That is, as... Figure 4 As shown, the thickness t1 of the second electrode 80 in the second region S2 is thinner than the thickness t3 of the piezoelectric layer 70 in the second region S2. Therefore, the second electrode 80 can be manufactured with high precision, and thus, the rigidity of the second electrode 80 in the Z-axis direction in the second region S2 can be adjusted to the desired value more easily. Therefore, strain on the active portion 310 in the second region S2 can be suppressed more appropriately.

[0078] As described above, the second electrode 80 in the first region S1 does not include the second layer 82, but is composed of the first layer 81 and the third layer 83, and its thickness t2 is thinner than the thickness t1 of the second electrode 80 in the second region S2. Therefore, the rigidity of the second electrode 80 in the Z-axis direction in the first region S1 is lower than that in the second region S2. Thus, excessive reduction in the deformation of the piezoelectric actuator 300 in the drive region is also suppressed.

[0079] Furthermore, the rigidity of the second electrode 80 in the second region S2 in the Z-axis direction can be adjusted by the materials and thicknesses of the first layer 81, the second layer 82, and the third layer 83. In particular, the rigidity of the second electrode 80 in the Z-axis direction in the second region S2 can be adjusted relatively easily by changing the thickness of the second layer 82, which is formed of an insulator or the like.

[0080] Further, although in the present embodiment, the second electrode 80 is exemplified as having a structure of a plurality of layers of the first layer 81, the second layer 82, and the third layer 83, the structure of the second electrode 80 is not particularly limited. The second electrode 80 can be configured by only one layer composed of a material having conductivity, or can be provided with a structure of a plurality of layers of four or more layers. Further, although in the present embodiment, the second layer 82 composed of an insulator is exemplified as being provided between the first layer 81 and the third layer 83 formed of a conductive material in the second electrode 80 of the second region S2, the second layer can not be sandwiched by the first layer 81 and the third layer 83. The respective layers of the second electrode 80 can also be stacked in the order of the first layer 81, the third layer 83, and the second layer 82 from the piezoelectric layer 70 side, for example.

[0081] Here, a plurality of samples having different rigidities in the Z-axis direction of the second electrode 80 in the second region S2 were prepared, and with respect to each sample, the relationship between the rigidity in the Z-axis direction of the second electrode 80, the breakdown voltage at which a crack or the like occurs in the piezoelectric layer 70, and the occurrence rate of defective products, that is, the process defect rate at the time of production was investigated. Figure 7

[0082] In the coordinate diagram shown in Figure 7 , the points at which the rigidity is 17490 N / m and 22870 N / m, and the breakdown voltage and the process defect rate are good at the points at which the rigidity is 17490 N / m and 22870 N / m are shown. From the coordinate diagram shown in Figure 7 , it is known that, if the rigidity of the second electrode 80 is approximately 17000 N / m or more, the breakdown voltage becomes high, and is approximately 130 V or more. In particular, if the rigidity is approximately 22000 N / m or more, the breakdown voltage is high, and is approximately 145 V or more, and no defective product occurs.

[0083] The process defect rate inspection refers to an inspection in which a voltage higher than that used when a piezoelectric device is normally used is applied, and a portion in which breakdown is likely to occur in a short time after use is made to appear. In the process defect rate inspection performed, a voltage higher than that at which ink droplets are ejected is applied to a liquid ejecting head as the piezoelectric device, and a portion in which breakdown is likely to occur in a short time after use is made to appear. In addition, in this inspection, a voltage lower than 145 V is applied to the liquid ejecting head.

[0084] Further, as shown in Figure 7 , it is known that, in the case where the rigidity is approximately 17000 N / m or more, the process defect rate sharply decreases. That is, it is known that, in the case where the rigidity is approximately 17000 N / m or more, even if a high voltage higher than that used when a liquid ejecting head is normally used is applied to the liquid ejecting head, the proportion of defective products sharply decreases. ​

[0085] According to the above, it is judged that by setting the rigidity in the Z-axis direction of the second electrode 80 in the second region S2 to 17,000 N / m or more, preferably 22,000 N / m or more, the defects of the piezoelectric layer 70 caused by repeated driving of the piezoelectric actuator 300 can be effectively suppressed.

[0086] However, as shown in FIG. 6, the rigidity in the Z-axis direction of the second electrode 80 in the second region S2 is 17,000 N / m or more, and the rigidity in the Z-axis direction of the second electrode 80 in the first region S1 is 17,000 N / m or less. Therefore, the rigidity in the Z-axis direction of the second electrode 80 in the second region S2 is higher than the rigidity in the Z-axis direction of the second electrode 80 in the first region S1. As a result, the piezoelectric layer 70 in the second region S2 is more likely to be deformed than the piezoelectric layer 70 in the first region S1. Therefore, the piezoelectric layer 70 in the second region S2 is more likely to be damaged than the piezoelectric layer 70 in the first region S1. In other words, the piezoelectric layer 70 in the second region S2 is more likely to be damaged than the piezoelectric layer 70 in the first region S1. Therefore, the piezoelectric layer 70 in the second region S2 is more likely to be damaged than the piezoelectric layer 70 in the first region S1. Figure 2 Figure 4 As shown in FIG. 6, on the outer side of the end portion 80b of the second electrode 80 in the -X direction, that is, on the further -X direction side of the end portion 80b of the second electrode 80, a wiring portion 85 is provided which is composed of the same layer as the second electrode 80 but is not electrically continuous with the second electrode 80. In the present embodiment, the wiring portion 85 is composed of the first layer 81 and the third layer 83 like the first region S1. Further, the wiring portion 85 is formed so as to cross over from the piezoelectric layer 70 to the first electrode 60 which is provided so as to extend in the -X direction compared to the piezoelectric layer 70, in a state in which the wiring portion 85 is spaced apart from the end portion 80b of the second electrode 80 in the -X direction without contacting the end portion 80b. The wiring portion 85 is provided independently for each active portion 310. That is, the wiring portion 85 is provided a plurality of times at predetermined intervals in the Y-axis direction. Although the wiring portion 85 can also be formed of a layer that is independent of the second electrode 80, it is preferable that the wiring portion 85 be formed of the same layer as the second electrode 80. By doing so, the manufacturing process of the wiring portion 85 can be simplified, and cost reduction can be achieved.

[0087] Further, on the first electrode 60 and the second electrode 80 which constitute the piezoelectric actuator 300, an independent lead electrode 91 and a common lead electrode 92 which is a common electrode for driving are connected, respectively. On the end portion of the independent lead electrode 91 and the common lead electrode 92 which is opposite to the end portion connected to the piezoelectric actuator 300, a wiring substrate 120 having flexibility is connected. In the present embodiment, the independent lead electrode 91 and the common lead electrode 92 are provided so as to extend in a manner in which they are exposed inside the through-hole 32 formed in the protective substrate 30, and are electrically connected to the wiring substrate 120 inside the through-hole 32. On the wiring substrate 120, a drive circuit 121 having a switching element for driving the piezoelectric actuator 300 is mounted.

[0088] Although the independent lead electrode 91 and the common lead electrode 92 are composed of the same layer in the present embodiment, they are formed in a manner in which they are not electrically continuous. By doing so, compared to a case in which the independent lead electrode 91 and the common lead electrode 92 are formed independently, the manufacturing process can be simplified, and cost reduction can be achieved. Of course, the independent lead electrode 91 and the common lead electrode 92 can also be formed of different layers.

[0089] ​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.

[0090] Individual lead electrodes 91 are provided for each active portion 310, that is, for each first electrode 60. For example... Figure 2 as well as Figure 4 As shown, the independent lead electrode 91 is connected to the vicinity of the end 60b of the first electrode 60 disposed on the outside of the piezoelectric layer 70 in the -X direction via the wiring portion 85, and is led out to the flow channel forming substrate 10 in the -X direction, and is actually led out to the vibrating plate 50 in the -X direction.

[0091] On the other hand, such as Figure 2 as well as Figure 4 As shown, 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, serving as a third electrode, extending along the Y-axis direction in a region corresponding to the end 12b on the -X direction side of the pressure chamber 12. Moreover, in this embodiment, the common lead electrode 92 has an extension portion 94 extending along the Y-axis direction in a 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.

[0092] Furthermore, the extension portion 93, serving as the third electrode, extends from the inside of the pressure chamber 12 to near the -X direction end 80b of the second electrode 80 on the outside of the pressure chamber 12. In this embodiment, the active portion 310 of the piezoelectric actuator 300 extends beyond the -X direction end 12b of the pressure chamber 12 to the outside of the pressure chamber 12, and the extension portion 93 extends from the active portion 310 to the outside of the pressure chamber 12.

[0093] In this embodiment, the extension portion 93, serving as the third electrode, is extended to the vicinity of the end portion 80b of the second electrode 80. That is, the extension portion 93 extends to the second region S2. By extending the extension portion 93 to the second region S2, strain on the active portion 310 is further suppressed, together with the second electrode 80. Therefore, the undesirable phenomenon of crack formation in the piezoelectric layer 70 can be suppressed more reliably.

[0094] However, the extension portion 93, serving as the third electrode, is provided on the portion of the second electrode 80 other than the end 80b. When the extension portion 93, serving as the common lead electrode 92, is provided at the end 80b of the second electrode 80, for example, the bonding layer of the common lead electrode 92, formed of a nickel-chromium alloy or a titanium-tungsten alloy, may come into contact with the piezoelectric layer 70, thereby generating leakage current. Therefore, it is preferable that the extension portion 93 is not extended to the end 80b of the second electrode 80 in the second region S2. That is, it is preferable that the end of the extension portion 93 on the -X direction side is located further inward than the end 80b, without coinciding with the end 80b of the second electrode 80.

[0095] Furthermore, in this case, it is preferable that the conductivity of the extension portion 93 serving as the third electrode in the second region S2 is higher than the conductivity of the second electrode 80. Additionally, it is preferable that the length of the extension portion 93 serving as the third electrode in the Z-axis direction in the second region S2 is longer than the length of the second electrode 80 in the Z-axis direction. Figure 4 As shown, preferably, in the second region S2, the thickness t4 of the extended portion 93 is thicker than the thickness t1 of the second electrode 80. By configuring it in this way, current can easily flow to the portion of the second electrode 80 where the extended portion 93 is formed in the second region S2, reducing the current flowing to the end 80b of the second electrode 80. Therefore, it is possible to further suppress undesirable phenomena such as cracks or burns in the piezoelectric layer 70 near the end 80b of the second electrode 80.

[0096] As explained above, in the liquid ejecting head, that is, the inkjet recording head 1 as one example of the piezoelectric device of the present embodiment, the flow path forming substrate 10 that is a substrate in which a plurality of pressure chambers 12 as recesses are formed, the vibration plate 50 that is provided on one face side of the flow path forming substrate, and the piezoelectric actuator 300 that has the first electrode 60, the piezoelectric layer 70, and the second electrode 80 stacked in the Z-axis direction as the first direction on the face side of the vibration plate 50 opposite to the flow path forming substrate 10 are provided. Further, when one region of two regions in the X-axis direction as the second direction crossing the Z-axis direction as the first direction, which is farther from the end portion 80b of the second electrode 80 is set as the first region S1, and one region closer to the end portion 80b of the second electrode 80 is set as the second region S2, the second electrode 80 is formed such that the rigidity in the Z-axis direction in the second region S2 is 17000 N / m or more and higher than the rigidity in the Z-axis direction in the first region S1, and the length in the Z-axis direction in the second region S2 is the length of the piezoelectric layer 70 in the first direction in the second region S2 or less.

[0097] When the piezoelectric actuator 300 is driven by such a structure, the strain of the active portion 310 in the vicinity of the end portion 80b of the second electrode 80, that is, in the second region S2 is suppressed. Therefore, the generation of the crack or the burnout of the piezoelectric layer 70 in the vicinity of the boundary between the active portion 310 and the inactive portion 320 of the piezoelectric actuator 300 can be suppressed.

[0098] Embodiment 2

[0099] Figure 8 is a sectional view of the inkjet recording head as one example of the liquid ejecting head according to Embodiment 2 of the present application, and is an enlarged view showing the structure of the piezoelectric actuator 300. In addition, the same reference numerals are given to the same components as those of Embodiment 1, and the repeated explanation is omitted.

[0100] As shown in Figure 8 , the piezoelectric actuator 300 according to the present embodiment is provided with the protective film 200 provided on the second electrode 80 on the -Z direction side, that is, on the second electrode 80. The end portion 80b of the second electrode 80 in the second region S2 is covered with the protective film 200. That is, the protective film 200 is provided so as to cover the boundary portion between the active portion 310 and the inactive portion 320 of the piezoelectric actuator 300. In addition, the structure other than the protective film 200 is the same as that of Embodiment 1.

[0101] In the piezoelectric layer 70 near the boundary between the active portion 310 and the inactive portion 320, for example, stress concentration occurs due to the fact that the state of strain becomes uneven, and in conjunction therewith, cracks or the occurrence of burnout due to the cracks become apparent. However, in the present embodiment, since the protective film 200 is provided so as to cover the boundary portion between the active portion 310 and the inactive portion 320, the occurrence of cracks and burnout in this region can be more reliably reduced.

[0102] Although in the example shown in FIG. 1, the protective film 200 is provided only near the end portion 80b of the second electrode 80, the range in which the protective film 200 is formed is not particularly limited. For example, the protective film 200 can also be provided so as to cover the portion of the inactive portion 320 in which the surface of the piezoelectric layer 70 is exposed. Figure 8

[0103] Further, although the material of the protective film 200 is not particularly limited, for example, an organic material such as polyimide (aromatic polyimide) or the like can be used. Further, the protective film 200 can also be formed from an epoxy-based adhesive or a silicon-based adhesive. Further, in the case where the protective film 200 is formed by an adhesive, it can also be configured so that the adhesive used to adhere the protective substrate 30 to the flow channel forming substrate 10 functions as the protective film 200. That is, it can also be configured so that the protective substrate 30 is adhered to the portion of the flow channel forming substrate 10 corresponding to the end portion 80b of the second electrode 80 by the adhesive, and the end portion 80b of the second electrode 80 is covered by the adhesive.

[0104] Further, it is preferable that the Young's modulus of the protective film 200 be lower than the Young's modulus of the second electrode 80 in the second region S2. In the present embodiment, since the protective film 200 is formed from an organic material such as polyimide or the like, for example, the Young's modulus of the protective film 200 is lower than the Young's modulus of the second electrode 80 formed from a metal such as iridium or the like. Due to this, piezoelectric strain of the piezoelectric layer 70 in the boundary portion between the active portion 310 and the inactive portion 320 becomes more difficult to occur, and further, since vibration is also easily absorbed, the occurrence of cracks and burnout in this region can be more reliably reduced.

[0105] Other Embodiments

[0106] The above describes each of the embodiments of the present application, but the basic structure of the present application is not limited to the above-described embodiments.

[0107] ​Although the structure in the vicinity of the end 80b of the second electrode 80 in the -Y direction is described as an example in the above-described embodiments, the present application can of course be applied to the end 80b of the second electrode 80 in the +Y direction. In the case where the boundary between the active portion 310 and the inactive portion 320 of the piezoelectric actuator 300 is present on the +Y direction outside of the pressure chamber 12, the above-described structure of the present application can be applied to the end 80a side of the second electrode 80 in the +Y direction.

[0108] Further, although the first electrode 60 constitutes an independent electrode for each active portion 310 and the second electrode 80 constitutes a common electrode for a plurality of active portions 310 in each of the above-described embodiments, the first electrode 60 can constitute a common electrode for a plurality of active portions 310 and the second electrode 80 can constitute an independent electrode for each active portion 310. Even in this case, the same effects as those of the above-described embodiments can be obtained.

[0109] Further, the recording head 1 of each of the above-described embodiments is mounted on an inkjet recording device as an example of a liquid ejecting device. Figure 9 A schematic diagram showing an example of an inkjet recording device as an example of a liquid ejecting device according to an embodiment.

[0110] In Figure 9 In the inkjet recording device I shown in FIG. 1, the recording head 1 is provided with the cartridge 2 constituting an ink supply unit in a detachable manner, and is mounted on the carriage 3. The carriage 3 on which the recording head 1 is mounted is provided so as to be movable in the axial direction of the carriage shaft 5 installed on the device main body 4.

[0111] Further, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 not shown, so that the carriage 3 on which the recording head 1 is mounted is moved along the carriage shaft 5. On the other hand, a convey roller 8 as a convey unit is provided in the device main body 4, and a recording sheet S as a recording medium is conveyed by the convey roller 8. Note that the convey unit that conveys the recording sheet S is not limited to the convey roller, but can be a belt or a roller, or the like.

[0112] In such an inkjet recording device I, while the recording sheet S is conveyed in the +X direction with respect to the recording head 1 and the carriage 3 is reciprocally moved in the Y direction with respect to the recording sheet S, ink droplets are ejected from the recording head 1, so that the ejection of the ink droplets, so-called printing, is performed across substantially the entire surface of the recording sheet S.

[0113] Further, although the recording head 1 is mounted on the carriage 3 and reciprocates in the Y direction as the main scanning direction in the above-described inkjet recording device I, the present application is not particularly limited thereto, and can be applied, for example, to a so-called line-type recording device in which the recording head 1 is fixed and printing is performed only by moving a recording sheet S such as paper in the X direction as the sub-scanning direction.

[0114] In addition, in the above-described embodiments, the inkjet recording head is exemplified as one example of the liquid ejecting head, and the inkjet recording device is exemplified as one example of the liquid ejecting apparatus, and the description is made, but the present application is an application widely targeting all liquid ejecting heads and liquid ejecting apparatuses, and of course, can be applied to a liquid ejecting head or a liquid ejecting apparatus that ejects a liquid other than ink. As other liquid ejecting heads, for example, various recording heads applied to image recording apparatuses such as printers, color material ejecting heads applied to the manufacture of color filters of liquid crystal displays and the like, electrode material ejecting heads applied to the formation of electrodes of organic EL (Electro Luminescence) displays, FEDs (Field Emission Displays), and the like, and biological organic matter ejecting heads applied to the manufacture of biochips and the like can be exemplified, and can be applied to liquid ejecting apparatuses having the related liquid ejecting heads.

[0115] Further, the present application can be applied not only to liquid ejecting heads typified by inkjet recording heads, but also to ultrasonic devices such as ultrasonic transmitters, ultrasonic motors, pressure sensors, pyroelectric sensors, and other piezoelectric devices.

[0116] Symbol Explanation

[0117] S1… first region; S2… second region; I… inkjet recording device (recording device); 1… inkjet recording head (recording head); 2… cartridge; 3… carriage; 4… device main body; 5… carriage shaft; 6… drive motor; 7… timing belt; 8… conveyance roller; 10… flow channel forming substrate (substrate); 11… partition wall; 12… pressure chamber (recess); 15… communication plate; 16… nozzle communication passage; 17… first manifold portion; 18… second manifold portion; 19… supply communication passage; 20… nozzle plate; 21… nozzle; 30… protective substrate; 31… holding portion; 32… through-hole; 40… housing member; 41… accommodation portion; 42… third manifold portion; 43… connection port; 44… guide inlet; 45… plastic substrate; 46… sealing film; 47… fixed substrate; 48… opening portion; 49… plastic portion; 50… vibration plate; 51… elastic film; 52… insulator film; 60… first electrode; 70… piezoelectric layer; 71… groove portion; 80… second electrode; 81… first layer; 82… second layer; 83… third layer; 85… wiring portion; 91… independent lead electrode; 92… common lead electrode; 93… extension arrangement portion (third electrode); 94… extension arrangement portion; 100… manifold; 120… wiring substrate; 121… drive circuit; 200… protective film; 300… piezoelectric actuator; 310… active portion; 320… inactive portion; S… recording sheet.

Claims

1. A piezoelectric device, characterized by, Possessing: a substrate formed with a plurality of recesses; a vibration plate provided on one face side of the substrate; a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on a face side of the vibration plate opposite the substrate, when one region of two regions in a second direction crossing the first direction of the second electrode farther from an end of the second electrode is set as a first region, and one region closer to the end of the second electrode is set as a second region, the second electrode is formed such that rigidity in the first direction in the second region is 17000 N / m or more, and higher than rigidity in the first direction in the first region, and a length in the first direction in the second region is the same as or less than a length in the first direction of the piezoelectric layer in the second region, the second electrode in the second region has a first layer provided between the second layer and the piezoelectric layer in the first direction, and a second layer provided continuously in the first direction with respect to the first layer, and has lower electrical conductivity than the first layer, the second electrode in the first region has the first layer continuously with respect to the piezoelectric layer in the first direction, but does not have the second layer.

2. The piezoelectric device according to claim 1, wherein the rigidity in the first direction in the second region of the second electrode is 22000 N / m or more.

3. The piezoelectric device according to claim 1 or 2, wherein the first region is in a driving region where the vibration plate is in contact with the recess, and the second region is in a non-driving region where the vibration plate is not in contact with the recess.

4. The piezoelectric device according to claim 1, wherein the second electrode in the second region further has a third layer provided continuously in the first direction with respect to the second layer, and has higher electrical conductivity than the second layer, the second electrode in the first region has the third layer.

5. The piezoelectric device according to claim 1, wherein a third electrode is provided continuously in the first direction with respect to the second electrode, in the second region, the third electrode is provided on a portion of the second electrode other than the end portion.

6. The piezoelectric device according to claim 5, wherein in the second region, the third electrode has higher electrical conductivity than the second electrode.

7. The piezoelectric device according to claim 5 or 6, wherein in the second region, a length in the first direction of the third electrode is longer than a length in the first direction of the second electrode.

8. The piezoelectric device according to claim 1, wherein an end portion of the second electrode in the second region is covered with a protective film.

9. The piezoelectric device according to claim 8, wherein a Young's modulus of the protective film is lower than a Young's modulus of the second electrode.

10. A liquid ejection head, characterized by, Possessing: a substrate formed with a plurality of recesses; a vibration plate provided on one face side of the substrate; a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on a face side of the vibration plate opposite to the substrate, when one of two regions in a second direction crossing the first direction of the second electrode, which is farther from an end of the second electrode, is set as a first region, and one closer to the end of the second electrode is set as a second region, the second electrode is formed such that rigidity in the first direction in the second region is 17000 N / m or more and higher than rigidity in the first direction in the first region, and a length in the first direction in the second region is equal to or less than a length in the first direction of the piezoelectric layer in the second region, the second electrode in the second region has a first layer provided between the second layer and the piezoelectric layer in the first direction, and a second layer provided continuously in the first direction with respect to the first layer and having lower electrical conductivity than the first layer, the second electrode in the first region has the first layer continuously with respect to the piezoelectric layer in the first direction, but does not have the second layer.

11. A liquid ejecting apparatus, comprising: the liquid ejecting head according to claim 10.

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