Element substrate and liquid ejection head

Abstract

To provide an element substrate capable of applying a uniform voltage to each piezoelectric element while maintaining high reliability.SOLUTION: The element substrate includes a pressure chamber, a diaphragm 403, and a piezoelectric device 406. The piezoelectric device includes a first electrode 501, a piezoelectric layer 502, a second electrode 503, an insulating layer 506, a first wiring 504, a second wiring 505, and a retainer 510. The piezoelectric device includes a first region 507 in which the first electrode, the insulating layer, and the first wiring are laminated, a second region 508 in which the first electrode, the piezoelectric layer, the insulating layer, and the holding member are laminated, and a third region in which the first electrode, the piezoelectric layer, the insulating layer, and the second wiring are laminated. The holding portion is electrically separated from the piezoelectric layer. This makes it possible to provide an element substrate capable of applying a uniform voltage to each piezoelectric element while maintaining high reliability.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an element substrate and a liquid ejection head. [Background technology]

[0002] 2. Description of the Related Art A liquid ejection head that ejects liquid such as ink may use an element substrate that includes a piezoelectric element that ejects liquid from an ejection port by displacing a vibration plate.

[0003] Patent Document 1 discloses a configuration in which a first wiring and a second wiring are connected to both longitudinal sides of a second electrode disposed on the upper surface of a piezoelectric layer. This configuration ensures that the film structure at both ends of the piezoelectric element is the same, ensuring equal mechanical rigidity on both sides. As a result, cracks can be suppressed, and the reliability of the element substrate can be improved. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-025796 Summary of the Invention [Problem to be solved by the invention]

[0005] In the case of Patent Document 1, the third wiring connected to the first electrode arranged on the underside is connected to the first electrode at a position away from the piezoelectric element to avoid short-circuiting between the first wiring and the second wiring. In this case, the first electrode between the connection position and the piezoelectric element functions as wiring.

[0006] On the other hand, to ensure the deformation amount of the piezoelectric element, it is necessary to form the first electrode as thin as possible. However, the thinner the film thickness of the first electrode, the higher the resistance of the first electrode, and therefore errors in film thickness lead to variations in the amount of voltage drop across the first electrode, and ultimately to variations in the voltage applied to each piezoelectric element. When using a first electrode with a long length that functions as wiring, as in Patent Document 1, the impact of these variations becomes even greater. Furthermore, variations in the voltage applied to each piezoelectric element lead to variations in the amount of displacement of the diaphragm, which in turn leads to variations in the amount of ejection, and when the liquid ejection device is used as a recording device, this appears as uneven density in the image.

[0007] Therefore, an object of the present disclosure is to provide an element substrate that is capable of applying a uniform voltage to each piezoelectric element while maintaining high reliability. [Means for solving the problem]

[0008] The element substrate includes a pressure chamber that contains a liquid, a vibration plate that forms a wall surface of the pressure chamber, and a piezoelectric device that vibrates the vibration plate, the piezoelectric device having a first electrode, a piezoelectric layer stacked in a predetermined direction relative to the first electrode, a second electrode stacked in the predetermined direction relative to the piezoelectric layer, an insulating layer stacked in the predetermined direction relative to the second electrode, a first wiring electrically connected to the first electrode, a second wiring electrically connected to the second electrode, and a pressing portion that partially presses the piezoelectric layer from the predetermined direction, the longitudinal direction of the piezoelectric layer is a direction along an X-axis that intersects with the predetermined direction, When one direction along the X-axis is defined as a −X direction and a direction along the X-axis opposite to the −X direction is defined as a +X direction, the piezoelectric element includes a first region in which the first electrode, the insulating layer, and the first wiring are stacked in this order in the predetermined direction, a second region located on the +X direction side of the first region in which the first electrode, the piezoelectric layer, the insulating layer, and the suppressing portion are stacked in this order in the predetermined direction, and a third region located on the +X direction side of the second region in which the first electrode, the piezoelectric layer, the insulating layer, and the second wiring are stacked in this order in the predetermined direction, and the suppressing portion is electrically isolated from the piezoelectric layer. [Effects of the Invention]

[0009] According to the technique of the present disclosure, it is possible to provide an element substrate that can apply a uniform voltage to each piezoelectric element while maintaining high reliability. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic perspective view of a liquid ejection device according to an embodiment. [Figure 2] FIG. 1 is a schematic perspective view of a liquid ejection head according to an embodiment. [Figure 3] FIG. 2 is a diagram schematically illustrating the configuration of an element substrate according to an embodiment. [Figure 4] Cross-sectional view of line IV-IV in Figure 3. [Figure 5] 1 is a schematic diagram of a piezoelectric device according to an embodiment. [Figure 6] FIG. 10 is a plan view of the periphery of a piezoelectric device according to a modified example. [Figure 7] FIG. 10 is a schematic diagram of a piezoelectric device according to a modified example. [Figure 8] FIG. 10 is a plan view of the periphery of a piezoelectric device according to a modified example. [Figure 9] FIG. 10 is a plan view of the periphery of a piezoelectric device according to a modified example. [Figure 10] FIG. 10 is a plan view of the periphery of a piezoelectric device according to a modified example. [Figure 11] FIG. 2 is a schematic plan view of an element substrate according to an embodiment. [Figure 12] Cross-sectional view of line XII-XII in Figure 11. [Figure 13] FIG. 2 is a schematic plan view of a piezoelectric element portion according to an embodiment. [Figure 14] Cross-sectional view taken along line XIV-XIV in Figure 13. [Figure 15] FIG. 10 is a diagram showing a simulation result according to an embodiment. [Figure 16] FIG. 10 is a schematic plan view of a piezoelectric element portion according to a modified example. [Figure 17] FIG. 10 is a schematic plan view of a piezoelectric element portion according to a modified example. [Figure 18] FIG. 10 is a schematic plan view of a piezoelectric element portion according to a modified example. [Figure 19] Cross-sectional view of line XIX-XIX in Figure 18. [Figure 20] FIG. 10 is a schematic plan view of a piezoelectric element portion according to a modified example. [Figure 21] Cross-sectional view of line XXI-XXI in Figure 20. [Figure 22] Cross-sectional view taken along line XXII-XXII in Figure 20. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] <Liquid discharge device 100> FIG. 1(a) is a schematic perspective view of a liquid ejection device 100 that can be applied to this embodiment.

[0012] The coordinate axes in the figure will be explained. The X-axis and Y-axis in the figure are perpendicular to each other on a plane. The Z-axis is perpendicular to the X-axis and Y-axis. The ±Y directions indicate the longitudinal direction of the liquid ejection head 101. The ±X directions indicate the lateral direction of the liquid ejection head 101. The -X direction is the transport direction of the recording medium P. The -X direction will be referred to as the transport direction as appropriate. The Z direction indicates the height direction of the liquid ejection head 101. The -Z direction is the direction in which liquid (e.g., ink) is ejected from the liquid ejection head 101. The surface of the liquid ejection head 101 facing the -Z direction is the bottom surface of the liquid ejection head 101.

[0013] In this disclosure, "recording" does not only mean forming meaningful information (for example, characters or figures that are visible to humans). "Recording" also means forming insignificant information. Furthermore, in this disclosure, "recording" broadly means forming an image, a design, a pattern, a structure, or a combination thereof on a recording medium P, or processing the medium.

[0014] "Recording medium" includes not only paper used in general recording devices, but also cloth, plastic film, metal plate, glass, ceramics, resin, wood, leather, and other materials that can accept liquid (for example, ink).

[0015] The recording medium P may be any material on which an image can be formed by impacting droplets (e.g., ink droplets). For example, various materials and shapes can be used, such as paper, cloth, optical disc label surfaces, plastic sheets, overhead projector sheets, and envelopes. In this embodiment, cut paper is used as the recording medium P.

[0016] In this disclosure, the description will be made assuming that ink is used as the liquid. However, the liquid that can be used in the technology of this disclosure is not limited to ink. Various recording liquids other than ink can be used as the liquid, including treatment liquids used for improving the fixation of ink on the recording medium P, reducing uneven gloss, and improving abrasion resistance.

[0017] 1(a), the liquid ejection device 100 of this embodiment is a full-line type inkjet recording device that uses a liquid ejection head 101 having a recording area corresponding to the width of the recording medium P. The recording medium P is mounted on a belt-like transport unit 103, and is transported in the transport direction (-X direction) at a predetermined speed as a transport roller 104 rotates.

[0018] A liquid ejection head 101 having a plurality of ejection ports 301 (see FIG. 3, etc.) capable of ejecting liquid is provided along the conveyance path. The liquid ejection head 101 ejects liquid from each of the ejection ports 301 in accordance with ejection data at a frequency corresponding to the conveyance speed of the recording medium P, thereby recording a desired image on the surface of the recording medium P.

[0019] FIG. 1B is a block diagram for explaining the control configuration of the liquid ejection device 100 that can be applied to this embodiment.

[0020] As shown in FIG. 1B, a CPU 110 controls the entire liquid ejection apparatus 100 in accordance with a program stored in a ROM 111 while using a RAM 112 as a work area.

[0021] For example, the CPU 110 performs predetermined image processing on image data received from an externally connected host device 120 in accordance with programs and parameters stored in the ROM 111, generating ejection data compatible with the liquid ejection head 101. The CPU 110 then drives the liquid ejection head 101 in accordance with this ejection data, causing liquid to be ejected at a predetermined frequency from each of the ejection ports 301. Furthermore, while the liquid ejection head 101 is performing such an ejection operation, the conveyance motor 113 is driven to rotate the conveyance roller 104, and the recording medium P is conveyed in the conveyance direction at a speed corresponding to the ejection frequency.

[0022] The liquid ejection head 101 of this embodiment ejects black ink, thereby enabling monochrome printing onto the recording medium P. However, full-color printing can be performed by providing four liquid ejection heads that individually eject yellow, magenta, cyan, and black inks, for example.

[0023] <Liquid ejection head 101> FIG. 2 is a schematic perspective view of a liquid ejection head 101 that can be applied to this embodiment.

[0024] 2, the liquid ejection head 101 has chip-like element substrates 200, which serve as liquid ejection modules, arranged in the Y direction in a number corresponding to the width of an A4 sheet of paper. In addition to the plurality of element substrates 200, the liquid ejection head 101 is also provided with an electric wiring board 201 and a plurality of flexible wiring boards 202 for connecting the element substrates 200 to the electric wiring board 201. The electric wiring board 201 is provided with a power supply terminal 203 for receiving power from the main body of the liquid ejection device 100 and a signal input terminal 204 for receiving ejection data.

[0025] The liquid ejection head 101 of this embodiment is provided with a piezoelectric layer 502 (see FIG. 5(a) etc.) as an energy element that generates energy for ejecting liquid. That is, the liquid ejection head 101 of this embodiment ejects liquid by a so-called piezoelectric method.

[0026] <Element substrate 200> 3 is a diagram schematically showing the configuration of an element substrate 200 that can be applied to this embodiment. FIG. 3 is an external view of the element substrate 200 as seen from the ejection port 301 side.

[0027] 3, in the element substrate 200 of this embodiment, a discharge port forming member 302 having a plurality of discharge ports 301 for discharging liquid is layered on an actuator substrate 303 that is driven by supplying power. In Fig. 3, the plurality of discharge ports 301 are formed in a row along the Y direction. However, the number of discharge ports 301 and the number of rows can be changed as appropriate.

[0028] The ejection port forming member 302 of this embodiment is made of a photosensitive resin or the like. A terminal section 304 including a plurality of terminals for electrically connecting to the flexible wiring board 202 (see FIG. 2) is provided on the upper surface of the actuator substrate 303. The shape of the terminal section 304 is appropriately designed and changed depending on the mounting method.

[0029] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG.

[0030] As shown in FIG. 4 , the element substrate 200 of this embodiment is fixed (for example, bonded) to a common liquid chamber substrate 408 having one common liquid chamber 407 that supplies liquid to a plurality of supply channels 409 provided in the element substrate 200. As described above, the element substrate 200 includes an ejection port formation member 302 and an actuator substrate 303. The actuator substrate 303 includes a first substrate 410 that includes a pressure chamber substrate 402 containing silicon and an elastic vibration plate 403, and a flow channel substrate 405 that also includes silicon. The pressure chamber substrate 402 is formed with pressure chambers 401 that temporarily store liquid. The vibration plate 403 is formed with an opening. The flow channel substrate 405 is formed with a cavity 404 that houses a piezoelectric device 406 that is driven by the supply of power, and a supply channel 409 that supplies liquid from the common liquid chamber 407 to the pressure chamber 401 via the opening in the vibration plate 403. Stacked in this order are the ejection port forming member 302, the pressure chamber substrate 402, the vibration plate 403, the flow path substrate 405, and the common liquid chamber substrate 408. The vibration plate 403 is an insulating film made of an elastic material such as silicon oxide.

[0031] Piezoelectric devices 406 corresponding to the pressure chambers 401 are provided on the flow path substrate 405. The piezoelectric devices 406 are provided on a vibration plate 403 and housed inside cavities 404. When a voltage is applied to the piezoelectric devices 406, the piezoelectric devices 406 deform so as to bend toward the inside of the pressure chambers 401. As the piezoelectric devices 406 deform, the vibration plate 403 deforms integrally with the piezoelectric devices 406. This reduces the volume of the pressure chambers 401, and pressure is applied to the liquid in the pressure chambers 401. When pressure is applied to the liquid in the pressure chambers 401, some of the liquid is ejected from the ejection ports 301 as droplets (for example, ink droplets). The amount of liquid consumed during ejection is replenished into the pressure chambers 401 via a common liquid chamber 407 and a supply flow path 409.

[0032] The pressure chamber 401 of this embodiment has a shape that is long in the direction along the X-axis, and the piezoelectric device 406 provided corresponding to the pressure chamber 401 also has a rectangular shape that is long in the X-axis direction.

[0033] FIG. 5(a) is a plan view of the vicinity of the piezoelectric device 406. FIG.

[0034] As shown in FIG. 5(a), in plan view, the shape of the piezoelectric device 406 is a rectangle having short sides extending in the Y direction and long sides extending in the X direction.

[0035] FIG. 5(b) is a cross-sectional view taken along line Vb-Vb in FIG. 5(a).

[0036] 5(b), the element substrate 200 (see FIG. 2, etc.) includes a pressure chamber 401 (see FIG. 4), a vibration plate 403 that forms the wall surface (specifically, the ceiling surface) of the pressure chamber 401, and a piezoelectric device 406 that vibrates the vibration plate 403. In the element substrate 200, a plurality of pressure chambers 401, a plurality of vibration plates 403, and a plurality of piezoelectric devices 406 are provided along the Y direction.

[0037] The piezoelectric device 406 includes a first electrode 501, a piezoelectric layer 502, a second electrode 503, a first wiring 504 electrically connected to the first electrode 501, a second wiring 505 electrically connected to the second electrode 503, and an insulating layer 506 for moisture prevention and insulation. When the longitudinal direction of the pressure chamber 401 is defined as the direction along the X axis, one direction along the X axis is defined as the −X direction, and the direction along the X axis opposite to the −X direction is defined as the +X direction, a first region 507, a second region 508, and a third region 509 are located in this order from the −X direction to the +X direction. That is, the second region 508 is located closer to the +X direction than the first region 507, and the third region 509 is located closer to the +X direction than the second region 508.

[0038] In a cross-sectional view of the piezoelectric device 406, in a first region 507, a first electrode 501, an insulating layer 506, and a first wiring 504 are stacked in this order. In a second region 508, a first electrode 501, a piezoelectric layer 502, a second electrode 503, an insulating layer 506, and a suppressing portion 510 are stacked in this order. In a third region 509, a first electrode 501, a piezoelectric layer 502, a second electrode 503, an insulating layer 506, and a second wiring 505 are stacked in this order. Here, the distance between the end of the first wiring 504 and the end of the suppressing portion 510 (i.e., the space where the conductive layer is removed) is approximately 5.0 μm.

[0039] The holding portion 510 is not connected to the first wiring 504, the first electrode 501, the piezoelectric layer 502, the second electrode 503, and the second wiring 505. Therefore, electricity does not flow through the holding portion 510.

[0040] In a cross-sectional view of the piezoelectric device 406, a first electrode 501 is laminated on a vibration plate 403. A piezoelectric layer 502 is laminated on the first electrode 501. A second electrode 503 is laminated on the piezoelectric layer 502. An insulating layer 506 is formed so as to cover the first electrode 501, the piezoelectric layer 502, and the second electrode 503. With the insulating layer 506 covering the first electrode 501, the piezoelectric layer 502, and the second electrode 503, a first opening 511 and a second opening 512 are formed in the insulating layer 506, penetrating the insulating layer 506 in the Z direction.

[0041] In the first region 507, a first wiring 504 is laminated on the insulating layer 506. The first wiring 504 is connected to the first electrode 501 through a first opening 511. In the second region 508, a pressing portion 510 that presses down on the piezoelectric layer 502 having a predetermined height is laminated on the insulating layer 506. When the piezoelectric device 406 is viewed in cross section, the shape of the piezoelectric layer 502 is a symmetrical trapezoid.

[0042] The suppressing portion 510 includes a first flat portion 513 that suppresses the first electrode 501 from above the insulating layer 506, and an inclined portion 514 that suppresses the inclined portion of the piezoelectric layer 502 from above the insulating layer 506. The suppressing portion 510 includes a second flat portion 515 that suppresses the second electrode 503, the upper and lower bases of the piezoelectric layer 502, and the first electrode 501 from above the insulating layer 506. The first flat portion 513, the inclined portion 514, and the second flat portion 515 are formed continuously in this order from the -X direction to the +X direction. In this way, the suppressing portion 510 is formed so as to ride over the piezoelectric layer 502 and the second electrode 503, which have a predetermined height from the -X direction side.

[0043] The first wiring 504, the suppressing portion 510, and the second wiring 505 are formed collectively by selectively removing a common conductive layer (single layer or multiple layers). Therefore, the first wiring 504, the suppressing portion 510, and the second wiring 505 are formed to approximately the same film thickness from a common conductive material.

[0044] For example, a conductive layer of a low-resistance metal such as gold is formed by a known film formation technique such as sputtering, and the conductive layer is selectively removed by a known processing technique such as photolithography, thereby forming the first wiring 504, the suppressing portion 510, and the second wiring 505 all at once. The film thicknesses of the first wiring 504, the suppressing portion 510, and the second wiring 505 are thicker than the film thickness of the second electrode 503. For example, the second electrode 503 is formed to have a sufficiently thin film thickness so as not to excessively suppress the deformation of the piezoelectric layer 502. On the other hand, the first wiring 504 and the second wiring 505 are ensured to have an appropriate film thickness so as to sufficiently reduce the electrical resistance.

[0045] By providing the restraining portion 510 in this manner, the rigidity of the −X direction side of the piezoelectric layer 502 can be made equal to the rigidity of the +X direction side of the piezoelectric layer 502 where the second wiring 505 is provided.

[0046] At the end of the piezoelectric layer 502 on the +X direction side, a first electrode 501, a piezoelectric layer 502, a second electrode 503, an insulating layer 506, and a second wiring 505 are laminated in this order. At the end of the piezoelectric layer 502 on the −X direction side, a first electrode 501, a piezoelectric layer 502, a second electrode 503, an insulating layer 506, and a suppressing portion 510 are laminated in this order.

[0047] The occurrence of cracks due to imbalance in rigidity can be suppressed by making the suppressing portion 510 from the same material as the second wiring 505 and making it the same thickness as the second wiring 505. If the suppressing portion 510 does not exist, the rigidity at both ends of the piezoelectric layer 502 in the X direction (longitudinal direction) will be imbalanced, and cracks may occur.

[0048] The holding portion 510 does not have to be spaced apart from the first wiring 504. However, in consideration of electrical safety, it is preferable that the holding portion 510 be spaced apart from the first wiring 504. In particular, when the first wiring 504 and the second wiring 505 are made of the same material, the holding portion 510 needs to be formed so as to be spaced apart from the first wiring 504.

[0049] When the suppressing portion 510 is connected to the first wiring 504, a voltage of the same potential is applied to the inclined portion 514 from the first electrode 501 and the suppressing portion 510 via the insulating layer 506, which is supplied from the first wiring 504. As a result of the application of a voltage of the same potential, the inclined portion 514 does not deform, and a local stress difference occurs at the boundary between the inclined portion 514 and the flat portion 116, which may cause cracks. By making the suppressing portion 510 an isolated pattern separated from the first wiring 504, it is possible to prevent such cracks from occurring.

[0050] The role of suppression portion 510 is to eliminate non-uniformity in rigidity by arranging it in contrast to second electrode 503. On the other hand, suppression portion 510 also has the role of acting in a direction that makes it difficult for diaphragm 403 to displace. In order to ensure the amount of displacement in response to the drive voltage, it is necessary to strike a balance between the shape and arrangement position of suppression portion 510.

[0051] As described above, in this embodiment, the first wiring 504, the pressing portion 510, and the second wiring 505 are made of the same material and are formed simultaneously by photolithography. This makes the pressing portion 510 and the second wiring 505, which cover the piezoelectric layer 502, have the same rigidity.

[0052] Furthermore, in this embodiment, the first electrode 501 is also used as wiring, but electricity does not pass through the suppressing portion 510. Therefore, no electrical problems arise even if the first wiring 504 and the suppressing portion 510 are brought closer to each other. With this configuration, the contact point between the first wiring 504 and the first electrode 501 can be located closer to the piezoelectric layer 502 than in the configuration of Patent Document 1. Therefore, with the configuration of this embodiment, the section in which the first electrode 501 is used as wiring can be made shorter than in the configuration of Patent Document 1. As a result, it is possible to suppress variations in electrical resistance among multiple piezoelectric devices 406 arranged in the Y direction and achieve uniform ejection amounts, more so than with the technology of Patent Document 1.

[0053] Furthermore, the end of the piezoelectric layer 502 on the −X direction side is held down by the holding portion 510, and the end of the piezoelectric layer 502 on the +X direction side is held down by the second wiring 505. This makes it possible to suppress the occurrence of cracks.

[0054] Therefore, according to the element substrate 200 of this embodiment, it is possible to apply a uniform voltage to each piezoelectric element while maintaining high reliability.

[0055] [First Modification of the First Embodiment] FIG. 6 is a plan view of the periphery of a piezoelectric device 406 in this modification.

[0056] 6, in a plan view of the piezoelectric device 406, the first flat portion 513 and the inclined portion 514 of the pressing portion 510 are formed to have the same width (length in the Y direction). However, the width (length in the Y direction) of the second flat portion 515 is formed to be smaller than the widths of the first flat portion 513 and the inclined portion 514.

[0057] The suppressing portion 510 having such a shape can efficiently displace the piezoelectric layer 502 while maintaining reliability.

[0058] [Second Modification of the First Embodiment] FIG. 7(a) is a plan view of the periphery of a piezoelectric device 406 in this modification.

[0059] 7(a), in a plan view of the piezoelectric device 406, the pressing portion 510 of this embodiment does not include a second flat portion 515. At the end of the piezoelectric layer 502 on the -X direction side, the first flat portion 513 of this embodiment has a width (length in the Y direction) that covers the entire area in the Y direction. The width (length in the Y direction) of the inclined portion 514 of this embodiment is the same as the width of the first flat portion 513. However, the length (length in the X direction) of the inclined portion 514 is shorter than any of the examples described above.

[0060] FIG. 7(b) is a cross-sectional view taken along line VII-VII in FIG. 7(a).

[0061] 7(b), the holding portion 510 of this embodiment holds down only the base of the piezoelectric layer 502. The inclined portion 514 of this embodiment is formed only halfway up the inclined portion of the piezoelectric layer 502.

[0062] In general, cracks tend to occur from near the base of the piezoelectric layer 502 toward the inside. In this modification, the suppressing portion 510 is provided only near the base of the piezoelectric layer 502, where cracks may occur. This configuration can increase the displacement efficiency of the piezoelectric layer 502 without applying an excessive load to the piezoelectric layer 502. The shape of the suppressing portion 510 is not limited as long as it can suppress only the base of the piezoelectric layer 502.

[0063] In this way, with a configuration in which only the base portion of the piezoelectric layer 502 is suppressed, it is possible to more efficiently suppress variations in electrical resistance while maintaining reliability.

[0064] [Third Modification of the First Embodiment] FIG. 8 is a plan view of the periphery of a piezoelectric device 406 in this modification.

[0065] As shown in FIG. 8, when the piezoelectric device 406 is viewed from above, the retaining portion 510 may be formed in a C-shape.

[0066] Even with this configuration, it is possible to more efficiently suppress variations in electrical resistance while maintaining reliability.

[0067] [Fourth Modification of the First Embodiment] FIG. 9 is a plan view of the periphery of a piezoelectric device 406 in this modification.

[0068] 9, in a plan view of the piezoelectric device 406, the holding portion 510 is divided into two. At the end of the piezoelectric layer 502 on the −X direction side, the two holding portions 510 hold down the end of the piezoelectric layer 502 on the +Y direction side and the end of the piezoelectric layer 502 on the −Y direction side, respectively.

[0069] Even with this configuration, it is possible to more efficiently suppress variations in electrical resistance while maintaining reliability.

[0070] [Fifth Modification of the First Embodiment] FIG. 10 is a plan view of the periphery of a piezoelectric device 406 in this modification.

[0071] 10, in a plan view of the piezoelectric device 406, at the end on the −X direction side, the pressing portion 510 of this embodiment presses down on the corner on the +Y direction side of the piezoelectric layer 502. Note that, although the pressing portion 510 presses down on the corner on the +Y direction side of the piezoelectric layer 502 in the example of Fig. 10, it may also press down on the corner on the −Y direction side.

[0072] Even with this configuration, it is possible to more efficiently suppress variations in electrical resistance while maintaining reliability.

[0073] [Second embodiment] Below, differences from the first embodiment will be mainly described, and components that are the same as or correspond to those in the first embodiment will be indicated by the same reference symbols, and their descriptions will be omitted as appropriate.

[0074] 4, the element substrate 200 of this embodiment includes a discharge port forming member 302, a first substrate 410, and a flow path substrate 405. Generally, when the element substrate 200 is manufactured using a general-purpose MEMS process, the discharge port forming member 302, the first substrate 410, and the flow path substrate 405 include silicon. However, the element substrate 200 may be formed by combining other members (for example, a mold, etc.) with a silicon substrate. In this embodiment, it is intended to ensure high reliability of the element substrate 200.

[0075] FIG. 11 is a schematic plan view of the element substrate 200 in this embodiment.

[0076] 11, in the element substrate 200 of this embodiment, a plurality of pressure chambers 401 are arranged along the Y direction. Two adjacent pressure chambers 401 along the Y direction are separated by a partition wall 1100. As a result, each of the plurality of pressure chambers 401 is hardly affected directly by the piezoelectric element portion 1200 (see FIG. 12) provided at a position corresponding to the adjacent pressure chamber 401.

[0077] The piezoelectric element part 1200 (see FIG. 12) includes a vibration plate 403 , a first electrode 501 , a piezoelectric layer 502 , a second electrode 503 , a first insulating film 1204 , a second insulating film 1205 , and a sealing film 1206 .

[0078] The vibration plate 403 (see FIG. 12, etc.) generates pressure in the liquid inside the pressure chamber 401 by the action of the piezoelectric layer 502. For example, when the state of the ink contained in the pressure chamber 401 is stable, a meniscus is formed at the ejection port 301. When a voltage is applied to the piezoelectric element portion 1200 in accordance with an ejection signal, the piezoelectric element portion 1200 deforms, causing the volume of the pressure chamber 401 to expand and contract.

[0079] In the pressure chamber 401, the combination of expansion and contraction breaks the meniscus, and droplets are ejected from the ejection port 301 to the outside air side (for example, the -Z direction side). In this way, in the piezoelectric element section 1200, pressure is applied to the liquid inside the pressure chamber 401 by the action of the piezoelectric device 406 (see FIG. 12) and the vibration plate 403. When the liquid inside the pressure chamber 401 is consumed by the ejection operation, liquid is resupplied from the common liquid chamber 407 (see FIG. 4) by capillary force, and a meniscus is reformed at the ejection port 301.

[0080] The material constituting diaphragm 403 is selected depending on mechanical properties, reliability, etc. Examples of materials for diaphragm 403 include silicon nitride film, silicon, metal, and heat-resistant glass.

[0081] Examples of methods for forming the piezoelectric layer 502 include vacuum sputtering, sol-gel solution deposition, and CVD (Chemical Vapor Deposition). The piezoelectric layer 502 may be fired after deposition. Examples of methods for heating the piezoelectric layer 502 include lamp annealing. The firing temperature for the piezoelectric layer 502 is at most 600°C to 800°C.

[0082] When manufacturing the piezoelectric element section 1200, the piezoelectric device 406 is formed directly on the diaphragm 403, and then they are fired together. However, the piezoelectric device 406 may be formed on a separate substrate, fired, and then peeled and transferred to the diaphragm 403 side. Alternatively, the piezoelectric device 406 may be formed on a separate substrate, peeled and transferred to the diaphragm 403 side, and then these may be integrally formed to manufacture the piezoelectric element section 1200.

[0083] A first electrode 501 is formed on one surface (the lower surface in the example of FIG. 12) of the piezoelectric layer 502, and a second electrode 503 is formed on the other surface (the upper surface in the example of FIG. 12) of the piezoelectric layer 502. Examples of materials for the first electrode 501 and the second electrode 503 when a firing process is performed include noble metals with high heat resistance (specifically, Pt, Ir, etc.). On the other hand, examples of materials for the first electrode 501 and the second electrode 503 when the firing process can be separated into multiple steps include Au-based alloys and Al-based alloys.

[0084] Considering the controllability of the piezoelectric layer 502, it is desirable to use a material with high linearity in response displacement to voltage and to drive within a highly linear voltage range. An example of a material for the piezoelectric layer 502 that satisfies these conditions is PZT ceramics. In reality, the saturation characteristics, hysteresis characteristics, and nonlinearity of electrostriction affect the displacement characteristics of the piezoelectric layer 502.

[0085] In the element substrate 200 of this embodiment (see FIG. 11), a plurality of ejection ports 301 are formed along the Y direction. The density at which these ejection ports 301 are formed (ejection port density) is not particularly limited. For example, the ejection port density may be 150 npi (nozzles per inch), 300 npi, or 600 npi, or the ejection port density may be higher than 600 npi.

[0086] The viscosity of the ink used as the liquid is between 1 cP and 20 cP. In this embodiment, the drive waveform of the piezoelectric element portion 1200 is adjusted so that the minimum amount of ink ejected from each of the multiple ejection ports 301 is several pL. For example, when the ejection port density is 300 npi, the width (length in the Y direction) of the pressure chamber 401 is narrower than when the ejection port density is 150 npi. For this reason, it is necessary to form the vibration plate 403 thin to ensure the required amount of displacement.

[0087] Generally, the drive frequency of each of the plurality of piezoelectric elements is 10 kHz or more and 100 kHz or less. This drive frequency is set taking into consideration the time required for ink to be ejected after voltage is applied to the piezoelectric element portion 1200, and for new ink to be filled in so that the next ejection operation is possible. A MEMS process using a silicon substrate is used to form the piezoelectric layer 502 and the pressure chambers 401.

[0088] The element substrate 200 of this embodiment is provided with a plurality of ejection port arrays 1101 along the X direction, each array consisting of a plurality of ejection port 301 formed at a specified density along the Y direction. The number of ejection port arrays 1101 is not limited. For example, the number of ejection port arrays 1101 may be two or eight. Generally, the length of the ejection port array 1101 (length in the Y direction) is approximately 0.5 inches or more and 1.5 inches or less. The liquid ejection head 101 of this embodiment (see FIG. 1(a) etc.) is made up of a combination of a plurality of element substrates 200.

[0089] The flow path substrate 405 of this embodiment (see FIG. 4, etc.) is provided with a wiring section 1102 for transmitting electrical signals corresponding to the first electrode 501 and the second electrode 503. The wiring section 1102 includes a first wiring 504 and a second wiring 505 (see FIG. 13, etc.). The terminal sections 304 may be concentrated on only one side of the flow path substrate 405, or may be divided and arranged on both sides of the flow path substrate 405.

[0090] 11, the terminal portion 304 is provided along the Y direction only at the end portion on the −X direction side of the flow path substrate 405. By providing the terminal portion 304 only at the end portion on one side, it is possible to reduce the number of mounting members and the number of processes. For example, when the flexible wiring board 202 equipped with an IC is connected to the terminal portion 304, providing the terminal portion 304 only on one side can reduce costs compared to when the terminal portion 304 is provided on both sides.

[0091] However, concentrating the wiring portions 1102 on one side increases the density of the wiring portions 1102. Therefore, in this case, the arrangement of the wiring portions 1102 is restricted, and it becomes necessary to optimize the arrangement of the wiring portions 1102. For example, by forming the wiring portions 1102 into a multi-layer structure, the wiring portions 1102 may be distributed among multiple layers, thereby avoiding the restriction on arranging the wiring portions 1102 in a planar space.

[0092] When the ejection ports 301 are formed at a high density, the width (length in the Y direction) of the pressure chamber 401 becomes narrow. Therefore, in order to eject a predetermined amount of ink, it is necessary to greatly displace the piezoelectric element portion 1200. As a result, the curvature of the vibration plate 403 when it deforms during ejection must be increased. If the curvature of the vibration plate 403 is increased, stress increases at the end of the piezoelectric element portion 1200, and peeling may occur. In particular, the rigidity of the lower part of the piezoelectric layer 502 is lower than that of the upper part. Therefore, when the piezoelectric element portion 1200 deforms, displacement is likely to occur at the lower part of the piezoelectric layer 502, and there is a risk of large distortion. In other words, there is a risk of peeling, cracks, etc. occurring near the end of the lower part of the piezoelectric layer 502.

[0093] Therefore, in the element substrate 200 of this embodiment, a metal film 1300 is provided on the end of the piezoelectric layer 502 near the first contact portion 1401 of the first electrode 501 (see FIG. 13). In this embodiment, the plurality of piezoelectric elements are provided at a density of 300 npi in the Y direction. Hereinafter, it is assumed that the density at which the plurality of ejection ports are formed is 300 npi.

[0094] It is also assumed that the length (length in the X direction) of the piezoelectric element part 1200 is 700 μm, and the width (length in the Y direction) of the piezoelectric element part 1200 is 50 mμ (width).

[0095] It is also assumed that the length of the pressure chamber 401 (length in the X direction) is 750 μm, the width of the pressure chamber 401 (length in the Y direction) is 55 μm, and the height of the pressure chamber 401 (length in the Z direction) is 100 μm. In this case, the width of the pressure chamber 401 is narrower than when the ejection port density is 150 npi. For this reason, it is necessary to secure the required amount of displacement by forming the diaphragm 403 thin.

[0096] In this case, the diameter of the discharge port 301 is approximately 20 μm. However, the diameter of the discharge port 301 may be adjusted depending on the specifications of the droplets. For example, the diameter of the discharge port 301 can be changed appropriately within the range of approximately 10 μm to 30 μm.

[0097] FIG. 12 is a cross-sectional view taken along line XII-XII in FIG.

[0098] 12, a membrane-like piezoelectric element portion 1200 is formed at a position corresponding to the pressure chamber 401. In the piezoelectric element portion 1200, a vibration plate 403 and a piezoelectric device 406 are laminated in this order from the side closest to the pressure chamber 401. In the vibration plate 403, a first oxide film 1201, a device layer 1202, and a second oxide film 1203 are laminated in this order from the side closest to the pressure chamber 401. The first oxide film 1201 is a BOX layer, and the device layer 1202 is a Si layer.

[0099] The piezoelectric device 406 is formed by laminating a first electrode 501, a piezoelectric layer 502, a second electrode 503, a first insulating film 1204, a second insulating film 1205, and a sealing film 1206 in this order from the side closest to the pressure chamber 401. When manufacturing the piezoelectric layer 502 using oxide ceramics, it may be preferable to form a reduction inhibitor film on the piezoelectric layer 502 before forming the insulating film. When forming a general insulating film, an SiO-based material may be used in a CVD apparatus.

[0100] However, this method may cause the oxide on the deposition side to be easily reduced during the gas reaction. Once this reduction occurs, the Schottky junction interface between the piezoelectric layer 502 and the second electrode 503 may collapse, reducing the leakage characteristics of the piezoelectric layer 502 and potentially reducing long-term reliability. To prevent this, it is effective to deposit an oxide film (not shown) such as Al2O3 using an ALD apparatus as a reduction-inhibiting film.

[0101] Thereafter, a first insulating film 1204 of SiO or SiN is formed as an insulating film for the electrodes by using CVD or TEOS (Tetra Eth Oxy Silane) or the like.

[0102] Next, an electrical contact portion for the piezoelectric layer 502 is formed on the first insulating film 1204. In this embodiment, a metal film 1300, which will be described later, is also formed at this time. That is, the first contact portion 1401, the second contact portion 1402, and the metal film 1300 are formed of the same material as the same layer on the first insulating film 1204. Examples of the material include aluminum (Al), but it is preferable that they are formed of a material different from the material used in the subsequent wiring formation process.

[0103] In the wiring formation process, an Al-based alloy film tends to be used, but other alloy films may also be used. Then, using CVD or TEOS, an SiO-based or SiN-based second insulating film 1205 and a sealing film 1206 are formed in sequence. Finally, the sealing film in the connection region of the terminal portion 304 is removed.

[0104] The piezoelectric element section 1200 deforms with each ejection operation. Therefore, if the film thickness of the upper layer of the piezoelectric layer 502 is too large, it becomes difficult to deform the piezoelectric element section 1200, making it difficult to obtain a suitable ejection operation. In order to efficiently deform the piezoelectric element section 1200, it is desirable to position the neutral plane defined by material mechanics near the interface between the piezoelectric device 406 and the vibration plate 403, preferably slightly toward the vibration plate 403.

[0105] When the first insulating film 1204 is additionally formed on the upper layer of the piezoelectric layer 502, the neutral plane is shifted to the inside of the piezoelectric layer 502. Therefore, when the first insulating film 1204 is additionally formed on the upper layer of the piezoelectric layer 502, it becomes difficult to deform the piezoelectric element portion 1200. Furthermore, when the sealing film 1206 is formed on the surface side of the piezoelectric layer 502, deformation of the piezoelectric element portion 1200 is also suppressed.

[0106] It is desirable to form a necessary film thickness in the portion requiring insulating and sealing functions. For example, it is desirable to form a film thickness sufficient to fulfill the insulating and sealing functions in the electrical contact portion. On the other hand, it is desirable to remove or thin a portion of the upper layer of the piezoelectric layer 502 so as to leave the minimum film thickness required as a sealing portion. This configuration makes it possible to improve the displacement efficiency of the bending deformation in the piezoelectric element portion 1200.

[0107] The inorganic film on the piezoelectric layer 502 is thinned and removed by a removal process using masking with a photoresist by photolithography processing and semiconductor plasma etching.

[0108] FIG. 13 is a schematic plan view of the piezoelectric element part 1200 in this embodiment.

[0109] 13, the length of the first electrode 501 in the X direction is smaller than the length of the pressure chamber 401 in the X direction, and the length of the first electrode 501 in the Y direction is smaller than the length of the pressure chamber 401 in the Y direction. A metal film 1300 is formed above the end portion of the second electrode 503 in the X direction (the left side in FIG. 13). The material of the metal film 1300 is an inorganic material. For example, the metal film 1300 is a film containing Al.

[0110] If the Young's modulus of the metal film 1300 is Young's modulus E and the Young's modulus of the piezoelectric layer 502 is Young's modulus Ep, then the value of the film thickness of the metal film 1300 multiplied by Young's modulus E is 10% to 80% of the film thickness of the piezoelectric layer 502 multiplied by Young's modulus Ep. The residual stress of the metal film 1300 is preferably within the range of -100 MPa to +100 MPa (weak compression to weak tension). This is because if the residual compressive stress or residual tensile stress is too strong, the metal film may peel off. The above values ​​are the conditions under which peeling can be suppressed, as a result of examining the suppression of peeling based on process tolerances.

[0111] The amount of protrusion (Lx_out) of the metal film 1300 from the end of the second electrode 503 to the outside in the X direction is preferably 5 μm or more.

[0112] Furthermore, the amount of protrusion (Lx_in) of the metal film 1300 from the end of the second electrode 503 to the inside is preferably 80% to 120% of the amount of protrusion (Lx_in2) of the second contact portion 1402 from the end of the second electrode 503 to the inside. In other words, it is preferable to satisfy the following (Formula 1).

[0113] (Formula 1)...(Lx_in2)×0.8 ≦ (Lx_in) ≦ (Lx_in2)×1.2

[0114] Furthermore, it is desirable that the width (Wc1) of the first contact portion 1401 is 70% or more and 100% or less of the width (We) of the first electrode 501. In other words, it is desirable that the following (Formula 2) is satisfied.

[0115] (Formula 2)...(We)×0.7 ≦ (Wc1) ≦ (We)

[0116] Furthermore, the width (Wc2) of the second contact portion 1402 is preferably 70% to 100% of the Y-direction width (Wp) of the piezoelectric layer 502 (see FIG. 12, etc.). In other words, it is preferable to satisfy the following (Equation 3).

[0117] (Formula 3)...(Wp)×0.7 ≦ (Wc2) ≦ Wp

[0118] Furthermore, it is desirable that the width (Wm) of the metal film 1300 is 80% or more of the width (Wc2) of the second contact portion 1402 and is equal to or less than the width (Wch) of the pressure chamber 401. In other words, it is desirable that the following (Equation 4) be satisfied.

[0119] (Formula 4)...(Wc2)×0.8 ≦ (Wm) ≦ (Wch)

[0120] Furthermore, as a result of examining process tolerances to suppress peeling while maintaining displacement that meets the specifications for the ejected droplets, it was possible to suppress peeling by satisfying the above conditions (Equation 1) to (Equation 4).

[0121] FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG.

[0122] 14 , a membrane-like piezoelectric device 406 is formed on the surface of the diaphragm 403 opposite the ceiling surface of the pressure chamber 401 at a position corresponding to the pressure chamber 401. The piezoelectric device 406 is formed by laminating a first electrode 501, a piezoelectric layer 502, a second electrode 503, a first insulating film 1204, a conductive layer, a second insulating film 1205, a first wiring 504, and a sealing film 1206 in this order from the pressure chamber 401 side. This conductive layer includes a first contact portion 1401, a second contact portion 1402, and a metal film 1300. In this conductive layer, the first contact portion 1401 and the second contact portion 1402 are insulated from each other, and the second contact portion 1402 and the metal film 1300 are insulated from each other.

[0123] The first insulating film 1204 insulates the first contact portion 1401 from the first electrode 501 in a region other than the connection region between the first contact portion 1401 and the first electrode 501. The second insulating film 1205 insulates the first contact portion 1401 from the first wiring 504 in a region other than the connection region between the first contact portion 1401 and the first wiring 504.

[0124] The first contact portion 1401 electrically connects the first electrode 501 and the first wiring 504, and the second contact portion 1402 electrically connects the second electrode 503 and the second wiring 505. At the first contact portion 1401, electricity passes from the first wiring 504 to the first electrode 501. At the second contact portion 1402, electricity passes from the second wiring 505 to the second electrode 503. As a result, when a voltage is applied between the first wiring 504 and the second wiring 505 via the piezoelectric layer 502, the vibration plate 403 deforms, and the liquid in the pressure chamber 401 is ejected from the ejection port 301.

[0125] The first insulating film 1204 of this embodiment covers the first electrode 501, the piezoelectric layer 502, and the second electrode 503. The metal film 1300 provided between the first insulating film 1204 and the second insulating film 1205 floats with respect to the first electrode 501, the second electrode 503, the first wiring 504, and the second wiring 505. That is, the metal film 1300 is not connected to the first electrode 501, the second electrode 503, the first wiring 504, and the second wiring 505, and is in a floating state in which no potential is specified. In addition, the metal film 1300 plays a role in matching the rigidity of the first contact portion side and the rigidity of the second contact portion side.

[0126] FIG. 15 is a diagram for explaining the effect of providing the metal film 1300. Specifically, it is a diagram showing the results of a simulation in which a voltage is applied to the piezoelectric layer 502 (see FIG. 12, etc.) of this embodiment to deform the diaphragm 403 (see FIG. 12, etc.). The horizontal axis indicates the position in the X direction in the piezoelectric layer 502, and the vertical axis indicates the displacement amount in the Z direction of the diaphragm 403 when a voltage is applied to the piezoelectric layer 502. In the diagram, the left side of the X coordinate corresponds to the left side of FIGS. 13 and 14, i.e., the side where the metal film 1300 is provided. The solid line graph in FIG. 15 shows the displacement amount of the diaphragm 403 in the piezoelectric element section 1200 of this embodiment (see FIG. 12, etc.). On the other hand, the dashed line graph in FIG. 15 shows the displacement amount of the diaphragm in the piezoelectric element section of a reference example that does not have the metal film 1300 (see FIG. 14, etc.). The piezoelectric element section 1200 of this embodiment and the piezoelectric element section of the reference example have the same configuration except for the presence or absence of the metal film 1300.

[0127] 15, in diaphragm 403 of this embodiment, the amount of displacement on the first contact portion 1401 (see FIG. 14, etc.) side and the amount of displacement on the second contact portion 1402 (see FIG. 14, etc.) side are approximately the same. On the other hand, in the diaphragm of the reference example, the amount of displacement on the first contact portion 1401 side is larger than the amount of displacement on the second contact portion 1402 side.

[0128] Furthermore, the amount of displacement on the first contact portion 1401 side of diaphragm 403 of this embodiment is smaller than the amount of displacement on the first contact portion 1401 side of the diaphragm of the reference example. The amount of displacement on the second contact portion 1402 side of diaphragm 403 of this embodiment is approximately the same as the amount of displacement on the second contact portion 1402 side of the diaphragm of the reference example.

[0129] The reason why the displacement amount is asymmetric in the reference example is that the second contact portion 1402 connected to the upper layer side of the piezoelectric layer 502 suppresses the displacement of the piezoelectric layer 502, while the first contact portion 1401 connected to the lower layer side does not have such an effect. By providing the metal film 1300 in a position approximately symmetrical to the second contact portion 1402 as in this embodiment, the displacement of the piezoelectric layer 502 can be appropriately suppressed also on the first contact portion 1401 side. As a result, the displacement amount of the diaphragm 403 in the Z direction when a voltage is applied to the piezoelectric layer 502 can be made approximately symmetrical in the X direction.

[0130] As described above, in the piezoelectric element portion of this embodiment, a metal film is formed in a position approximately symmetrical to the second contact portion on the upper layer of the second electrode 503, thereby improving the rigidity of the first contact portion side. As a result, when a voltage is applied to the piezoelectric layer 502, the vibration plate 403 can be deformed in an approximately symmetrical manner in the X direction, and peeling or cracking on the first contact portion side can be suppressed.

[0131] Therefore, the element substrate of this embodiment enables stable ejection operations and maintains high reliability.

[0132] [Modification 1 of the second embodiment] FIG. 16 is a schematic plan view of a piezoelectric element part 1200 in this modified example.

[0133] 16, the metal film 1300 may be formed to cover the corners of the second electrode 503. This configuration can further prevent peeling on the first contact portion 1401 side compared to a configuration in which the corners of the second electrode 503 are not covered with the metal film 1300.

[0134] [Modification 2 of the second embodiment] FIG. 17 is a schematic plan view of a piezoelectric element part 1200 in this modified example.

[0135] 17, in a plan view of the piezoelectric element portion 1200, the metal film 1300 may be formed in a substantially C-shape and cover the corners of the second electrode 503. This configuration can further prevent peeling on the first contact portion 1401 side, compared to a configuration in which the corners of the second electrode 503 are not covered by the metal film 1300.

[0136] [Modification 3 of the second embodiment] 18 and 19 are schematic plan views of a piezoelectric element part 1200 in this modified example, and FIG. 19 is a cross-sectional view taken along line XIX-XIX in FIG.

[0137] As shown in FIG. 19, in the piezoelectric element part 1200 of this modified example, the metal film 1300 also functions as a first contact part 1401.

[0138] 19, the metal film 1300 of this modification is formed as the same layer as the first electrode contact (first contact portion 1401). The metal film 1300 extends outward along the first insulating film 1204 and is connected to the first electrode 501. That is, the metal film 1300 of this modification serves to suppress displacement of the piezoelectric layer 502 and to electrically connect the first electrode 501 and the first wiring 504. This configuration also makes it possible to appropriately suppress displacement of the piezoelectric layer 502 on the first contact portion 1401 side and prevent peeling.

[0139] [Modification 4 of the Second Embodiment] 20 is a schematic plan view of a piezoelectric element part 1200 in this modified example, FIG. 21 is a cross-sectional view taken along line XXI-XXI in FIG. 20, and FIG. 22 is a cross-sectional view taken along line XXII-XXII in FIG.

[0140] As shown in FIGS. 21 and 22, the piezoelectric element part 1200 of this modification does not include the second insulating film 1205 (see FIG. 12 etc.), and a sealing film 1206 is formed directly on the first insulating film 1204.

[0141] 22, in the piezoelectric element part 1200 of this modified example, the first contact part 1401 and the second contact part 1402 are formed in the same layer. Therefore, in the piezoelectric element part 1200 of this modified example, there is no need to form the second insulating film 1205 (see FIG. 12, etc.) for insulating the second contact part 1402 formed in a layer above the first contact part 1401. By forming the first insulating film 1204, it is possible to insulate both the first contact part 1401 and the second contact part 1402.

[0142] Therefore, with this configuration, the time and effort required to form the second insulating film 1205 can be reduced.

[0143] [Other embodiments] In the first embodiment, the first wiring 504, the pressure portion 510, and the second wiring 505 are made of gold. However, the materials that can be used for the first wiring 504, the pressure portion 510, and the second wiring 505 are not limited to gold. For example, the first wiring 504, the pressure portion 510, and the second wiring 505 may be made of aluminum. When the first wiring 504, the pressure portion 510, and the second wiring 505 are made of aluminum, it is preferable that the film thickness of these be approximately 500 nm or more. With this configuration, it is possible to obtain the same effects as in the first embodiment.

[0144] In addition, the liquid may be supplied to the element substrate 200 from a tank that is detachable from the liquid ejection head 101, or the liquid may be supplied to the element substrate 200 from a tank provided outside the liquid ejection head 101 via a tube or the like.

[0145] The liquid ejection device 100 may also include a pump and a flow path for circulating the liquid that has not been ejected from the element substrate 200 between the element substrate 200 and a tank that contains the liquid.

[0146] The components described in the above-described embodiments are merely examples. Therefore, the technical scope of the present disclosure is not limited to the above-described examples. The present disclosure has shown an example using a liquid ejection method. However, the technology of the present disclosure is not limited to this example, and various modifications or changes can be made within the scope of the gist thereof.

[0147] The present disclosure includes the following configurations.

[0148] (Configuration 1) An element substrate including a pressure chamber that contains a liquid, a vibration plate that forms a wall surface of the pressure chamber, and a piezoelectric device that vibrates the vibration plate, The piezoelectric device is A first electrode; a piezoelectric layer laminated in a predetermined direction relative to the first electrode; a second electrode laminated on the piezoelectric layer in the predetermined direction; an insulating layer stacked in the predetermined direction relative to the second electrode; a first wiring electrically connected to the first electrode; a second wiring electrically connected to the second electrode; a pressing portion that partially presses the piezoelectric layer from the predetermined direction; and the longitudinal direction of the piezoelectric layer is a direction along an X-axis that intersects with the predetermined direction, When one direction along the X axis is defined as a −X direction and a direction along the X axis opposite to the −X direction is defined as a +X direction, a first region in which the first electrode, the insulating layer, and the first wiring are stacked in this order in the predetermined direction; a second region located closer to the +X direction than the first region, in which the first electrode, the piezoelectric layer, the insulating layer, and the suppressing portion are stacked in this order in the predetermined direction; a third region located closer to the +X direction than the second region, in which the first electrode, the piezoelectric layer, the insulating layer, and the second wiring are stacked in this order in the predetermined direction; Including, the suppressing portion is electrically isolated from the piezoelectric layer. An element substrate comprising:

[0149] (Configuration 2) the suppressing portion is made of the same material as the second wiring and has the same thickness as the second wiring; The element substrate according to configuration 1.

[0150] (Configuration 3) the pressing portion is made of the same material as the first wiring and has the same thickness as the first wiring; 3. The element substrate according to claim 1 or 2.

[0151] (Configuration 4) the suppressing portion is not electrically connected to the first wiring and the second wiring; 4. The element substrate according to any one of the first to third aspects.

[0152] (Configuration 5) the suppressing portion is provided so as to cover the piezoelectric layer along an inclined surface shape of the piezoelectric layer having a height in the predetermined direction. 5. The element substrate according to any one of the first to fourth aspects.

[0153] (Configuration 6) When viewed in the predetermined direction and a direction along a Y-axis intersecting the X-axis, the suppressing portion and the second wiring are provided at positions symmetrical with respect to the piezoelectric layer. 6. The element substrate according to any one of the first to fifth aspects.

[0154] (Configuration 7) The holding portion is a first flat portion in which the insulating layer and the pressing portion are stacked in parallel in a direction along the X-axis; an inclined portion adjacent to the first flat portion in the +X direction, where the insulating layer and the suppressing portion are laminated along an inclined portion of the piezoelectric layer; a second flat portion adjacent to the inclined portion in the +X direction, in which the insulating layer and the suppressing portion are stacked in parallel in a direction along the X axis; Including, 7. The element substrate according to any one of the first to sixth aspects.

[0155] (Configuration 8) When viewed from the predetermined direction, the first flat portion, the inclined portion, and the second flat portion have equal widths in a direction along the Y-axis that intersects with a direction along the X-axis. 8. The element substrate according to configuration 7.

[0156] (Configuration 9) When viewed from the predetermined direction, the widths of the first flat portion and the inclined portion in a direction along the Y axis that intersects with the direction along the X axis are equal, The width of the second flat portion in the direction along the Y axis is smaller than the widths of the first flat portion and the inclined portion. 9. The element substrate according to configuration 7 or 8.

[0157] (Configuration 10) the pressing portion presses only the vicinity of the base of the piezoelectric layer, 10. The element substrate according to any one of the first to ninth aspects.

[0158] (Configuration 11) When viewed from the predetermined direction, the holding portion is provided in a C-shape. 11. The element substrate according to any one of the first to tenth embodiments.

[0159] (Configuration 12) When viewed from the predetermined direction, The holding portion is The piezoelectric layer includes a first pressing portion that presses one end of the piezoelectric layer in a direction along the Y axis that intersects with the direction along the X axis, and a second pressing portion that presses the other end, the first pressing portion being located at an end on the −X direction side of the piezoelectric layer. 12. The element substrate according to any one of the first to eleventh aspects.

[0160] (Configuration 13) When viewed from the predetermined direction, The holding portion is One end of the piezoelectric layer on the −X direction side in a direction along the Y axis intersecting the direction along the X axis is pressed down, while the other end is not pressed down. 13. The element substrate according to any one of the first to second aspects.

[0161] (Configuration 14) a plurality of the piezoelectric devices are arranged in a direction along a Y-axis that intersects with the predetermined direction and the direction along the X-axis; further comprising a plurality of outlets corresponding to the piezoelectric devices, 14. The element substrate according to any one of configurations 1 to 13.

[0162] (Configuration 15) An element substrate according to any one of configurations 1 to 14, A voltage is applied between the first electrode and the second electrode to vibrate the vibration plate and eject liquid from the ejection port. A liquid ejection head characterized by:

[0163] (Configuration 16) An element substrate including a pressure chamber that contains a liquid, a vibration plate that forms a wall surface of the pressure chamber, and a piezoelectric device that vibrates the vibration plate, The piezoelectric device is A first electrode; a piezoelectric layer laminated in a predetermined direction relative to the first electrode; a second electrode laminated on the piezoelectric layer in the predetermined direction; a first insulating layer stacked in the predetermined direction relative to the second electrode; a metal film laminated on the first insulating layer in the predetermined direction; a first wiring that supplies power to the first electrode; a second wiring that supplies power to the second electrode; and the first electrode and the first wiring are electrically connected via a first contact portion at one end of the piezoelectric layer in a longitudinal direction; the second electrode and the second wiring are electrically connected via a second contact portion at the other end opposite to the one end in the longitudinal direction, When viewed along the predetermined direction, the first contact portion and the second contact portion are arranged in an area overlapping with the pressure chamber, the metal film is disposed in a position different from the first contact portion and equivalent to the second contact portion in the predetermined direction; An element substrate comprising:

[0164] (Configuration 17) the metal film is formed of a material different from that of the first wiring and the second wiring; 17. The element substrate according to claim 16.

[0165] (Configuration 18) the metal film is formed in the same layer as the first contact portion and the second contact portion and is made of the same material as the first contact portion and the second contact portion; 18. The element substrate according to claim 16 or 17.

[0166] (Configuration 19) the metal film and the first contact portion are connected to each other. 19. The element substrate according to any one of configurations 16 to 18.

[0167] (Configuration 20) the metal film is not connected to the first electrode, the second electrode, the first wiring, or the second wiring, and is in a floating state in which no potential is specified; 19. The element substrate according to any one of configurations 16 to 18.

[0168] (Configuration 21) the metal film covers the corners of the second electrode. 20. The element substrate according to any one of configurations 16 to 19.

[0169] (Configuration 22) In the longitudinal direction, the metal film protrudes outward from the end of the second electrode by 5 μm or more. 20. The element substrate according to any one of configurations 16 to 19.

[0170] (Configuration 23) In the longitudinal direction, when the length of the metal film extending inward from the end of the second electrode is Lx_in and the length of the second contact portion extending inward from the end of the second electrode is Lx_in2, the following formula is satisfied: Lx_in2×0.8 ≦ Lx_in ≦ Lx_in2×1.2 20. The element substrate according to any one of configurations 16 to 19.

[0171] (Configuration 24) In a width direction intersecting the longitudinal direction in a plane, when the length of the second contact portion is Wc2 and the length of the piezoelectric layer is Wp, the following formula is satisfied: Wp × 0.7 ≦ Wc2 ≦ Wp 20. The element substrate according to any one of configurations 16 to 19.

[0172] (Configuration 25) In a width direction intersecting the longitudinal direction in a plane, when the length of the first contact portion is Wc1 and the length of the first electrode is We, the following formula is satisfied: We × 0.7 ≦ Wc1 ≦ We 20. The element substrate according to any one of configurations 16 to 19.

[0173] (Configuration 26) In a width direction intersecting the longitudinal direction in a plane, when the length of the metal film is Wm, the length of the second contact portion is Wc2, and the length of the pressure chamber is Wch, the following formula is satisfied: Wc2×0.8 ≦ Wm ≦ Wch 20. The element substrate according to any one of configurations 16 to 19.

[0174] (Configuration 27) The Young's modulus of the metal film is 10% or more and 80% or less of the Young's modulus of the piezoelectric layer. 20. The element substrate according to any one of configurations 16 to 19.

[0175] (Configuration 28) The residual stress of the metal film is in the range of −100 MPa to +100 MPa. 20. The element substrate according to any one of configurations 16 to 19.

[0176] (Configuration 29) the material of the metal film is an inorganic material containing Al, and is the same as the material of the first contact portion or the material of the second contact portion; 20. The element substrate according to any one of configurations 16 to 19.

[0177] (Configuration 30) the first contact portion and the second contact portion are provided within a range of the length of the pressure chamber in the longitudinal direction; 20. The element substrate according to any one of configurations 16 to 19.

[0178] (Configuration 31) the length of the first electrode in the longitudinal direction is smaller than the length of the pressure chamber in the longitudinal direction; a length of the first electrode in a width direction intersecting the longitudinal direction in a plane thereof is smaller than a length of the front pressure chamber in the width direction; 20. The element substrate according to any one of configurations 16 to 19.

[0179] (Configuration 32) a second insulating layer laminated on the metal film in the predetermined direction; a sealing film laminated on the second insulating layer in the predetermined direction; Further comprising: 20. The element substrate according to any one of configurations 16 to 19.

[0180] (Configuration 33) The semiconductor device further includes a sealing film laminated in the predetermined direction with respect to the first insulating layer and the metal film. 20. The element substrate according to any one of configurations 16 to 19.

[0181] (Configuration 34) 19. An element substrate according to claim 16, A voltage is applied between the first electrode and the second electrode to vibrate the vibration plate and eject liquid from the ejection port. A liquid ejection head characterized by:

Claims

1. An element substrate including a pressure chamber that contains a liquid, a vibration plate that forms a wall surface of the pressure chamber, and a piezoelectric device that vibrates the vibration plate, The piezoelectric device is A first electrode; a piezoelectric layer laminated in a predetermined direction relative to the first electrode; a second electrode laminated on the piezoelectric layer in the predetermined direction; an insulating layer stacked in the predetermined direction relative to the second electrode; a first wiring electrically connected to the first electrode; a second wiring electrically connected to the second electrode; a pressing portion that partially presses the piezoelectric layer from the predetermined direction; and the longitudinal direction of the piezoelectric layer is a direction along an X-axis that intersects with the predetermined direction, When one direction along the X axis is defined as a −X direction and a direction along the X axis opposite to the −X direction is defined as a +X direction, a first region in which the first electrode, the insulating layer, and the first wiring are stacked in this order in the predetermined direction; a second region located on the +X direction side of the first region, in which the first electrode, the piezoelectric layer, the insulating layer, and the suppressing portion are stacked in this order in the predetermined direction; a third region located on the +X direction side of the second region, in which the first electrode, the piezoelectric layer, the insulating layer, and the second wiring are stacked in this order in the predetermined direction; Including, the suppressing portion is electrically isolated from the piezoelectric layer. An element substrate comprising:

2. the suppressing portion is formed of the same material as the second wiring and has the same thickness as the second wiring; The element substrate according to claim 1 .

3. the suppressing portion is formed of the same material as the first wiring and has the same thickness as the first wiring; The element substrate according to claim 1 or 2.

4. the suppressing portion is not electrically connected to the first wiring and the second wiring; The element substrate according to claim 1 or 2.

5. the suppressing portion is provided so as to cover the piezoelectric layer along an inclined surface shape of the piezoelectric layer having a height in the predetermined direction. The element substrate according to claim 1 or 2.

6. When viewed in the predetermined direction and a direction along a Y-axis intersecting the X-axis, the suppressing portion and the second wiring are provided at positions symmetrical with respect to the piezoelectric layer. The element substrate according to claim 1 or 2.

7. The holding portion is a first flat portion in which the insulating layer and the suppressing portion are stacked in parallel in a direction along the X-axis; an inclined portion adjacent to the first flat portion in the +X direction, where the insulating layer and the suppressing portion are laminated along an inclined portion of the piezoelectric layer; a second flat portion adjacent to the inclined portion in the +X direction, in which the insulating layer and the suppressing portion are stacked in parallel in a direction along the X axis; The element substrate according to claim 1 , comprising:

8. The element substrate according to claim 7 , wherein when viewed from the predetermined direction, the first flat portion, the inclined portion, and the second flat portion have the same width in a direction along the Y axis that intersects with the direction along the X axis.

9. When viewed from the predetermined direction, the widths of the first flat portion and the inclined portion in a direction along the Y axis intersecting with the direction along the X axis are equal to each other, The element substrate according to claim 7 , wherein a width of the second flat portion in the direction along the Y axis is smaller than a width of the first flat portion and a width of the inclined portion.

10. the pressing portion presses only the vicinity of the base of the piezoelectric layer, The element substrate according to claim 1 or 2.

11. When viewed from the predetermined direction, the holding portion is provided in a C-shape. The element substrate according to claim 1 or 2.

12. When viewed from the predetermined direction, The holding portion is The piezoelectric layer includes a first suppressing portion that suppresses one end of the piezoelectric layer in a direction along a Y axis that intersects with the direction along the X axis, and a second suppressing portion that suppresses the other end of the piezoelectric layer, the first suppressing portion being located at an end on the −X direction side of the piezoelectric layer, The element substrate according to claim 1 or 2.

13. When viewed from the predetermined direction, The holding portion is one end of the piezoelectric layer on the −X direction side in a direction along the Y axis intersecting the direction along the X axis is pressed down, and the other end is not pressed down; The element substrate according to claim 1 or 2.

14. a plurality of the piezoelectric devices are arranged in a direction along a Y-axis that intersects with the predetermined direction and the direction along the X-axis; further comprising a plurality of outlets corresponding to the piezoelectric devices, The element substrate according to claim 1 or 2.

15. The element substrate according to claim 1 or 2 is provided, A voltage is applied between the first electrode and the second electrode to vibrate the vibration plate, thereby ejecting liquid from the ejection port. A liquid ejection head characterized by:

16. An element substrate including a pressure chamber that contains a liquid, a vibration plate that forms a wall surface of the pressure chamber, and a piezoelectric device that vibrates the vibration plate, The piezoelectric device is A first electrode; a piezoelectric layer laminated in a predetermined direction relative to the first electrode; a second electrode laminated on the piezoelectric layer in the predetermined direction; a first insulating layer stacked in the predetermined direction relative to the second electrode; a metal film laminated on the first insulating layer in the predetermined direction; a first wiring that supplies power to the first electrode; a second wiring that supplies power to the second electrode; and the first electrode and the first wiring are electrically connected via a first contact portion at one end of the piezoelectric layer in a longitudinal direction; the second electrode and the second wiring are electrically connected via a second contact portion at the other end opposite to the one end in the longitudinal direction, When viewed along the predetermined direction, the first contact portion and the second contact portion are arranged in an area overlapping with the pressure chamber, the metal film is disposed at a position different from the first contact portion and equivalent to the second contact portion in the predetermined direction; An element substrate comprising:

17. the metal film is formed of a material different from that of the first wiring and the second wiring; The element substrate according to claim 16 .

18. the metal film is formed in the same layer as the first contact portion and the second contact portion and is made of the same material as the first contact portion and the second contact portion; 18. The element substrate according to claim 16 or 17.

19. the metal film and the first contact portion are connected to each other.

18. The element substrate according to claim 16 or 17.

20. the metal film is not connected to the first electrode, the second electrode, the first wiring, or the second wiring, and is in a floating state in which no potential is specified; 18. The element substrate according to claim 16 or 17.

21. the metal film covers the corners of the second electrode.

18. The element substrate according to claim 16 or 17.

22. In the longitudinal direction, the metal film protrudes outward from the end of the second electrode by 5 μm or more.

18. The element substrate according to claim 16 or 17.

23. In the longitudinal direction, when a length of the metal film extending inward from an end of the second electrode is Lx_in and a length of the second contact portion extending inward from the end of the second electrode is Lx_in2, the following formula is satisfied: Lx_in2×0.8 ≦ Lx_in ≦ Lx_in2×1.2 18. The element substrate according to claim 16 or 17.

24. In a width direction intersecting the longitudinal direction in a plane, when the length of the second contact portion is Wc2 and the length of the piezoelectric layer is Wp, the following formula is satisfied: Wp × 0.7 ≦ Wc2 ≦ Wp 18. The element substrate according to claim 16 or 17.

25. In a width direction intersecting the longitudinal direction in a plane, when the length of the first contact portion is Wc1 and the length of the first electrode is We, the following formula is satisfied: We × 0.7 ≦ Wc1 ≦ We 18. The element substrate according to claim 16 or 17.

26. In a width direction intersecting the longitudinal direction in a plane, when the length of the metal film is Wm, the length of the second contact portion is Wc2, and the length of the pressure chamber is Wch, the following formula is satisfied: Wc2×0.8 ≦ Wm ≦ Wch 18. The element substrate according to claim 16 or 17.

27. the Young's modulus of the metal film is 10% or more and 80% or less of the Young's modulus of the piezoelectric layer; 18. The element substrate according to claim 16 or 17.

28. The residual stress of the metal film is in the range of −100 MPa to +100 MPa.

18. The element substrate according to claim 16 or 17.

29. the material of the metal film is an inorganic material containing Al, and is the same as the material of the first contact portion or the material of the second contact portion; 18. The element substrate according to claim 16 or 17.

30. the first contact portion and the second contact portion are provided within a range of the length of the pressure chamber in the longitudinal direction; 18. The element substrate according to claim 16 or 17.

31. the length of the first electrode in the longitudinal direction is smaller than the length of the pressure chamber in the longitudinal direction; a length of the first electrode in a width direction intersecting the longitudinal direction on a plane thereof is smaller than a length of the front pressure chamber in the width direction; 18. The element substrate according to claim 16 or 17.

32. a second insulating layer laminated on the metal film in the predetermined direction; a sealing film laminated on the second insulating layer in the predetermined direction; Further comprising:

18. The element substrate according to claim 16 or 17.

33. The semiconductor device further includes a sealing film laminated in the predetermined direction with respect to the first insulating layer and the metal film.

18. The element substrate according to claim 16 or 17.

34. The element substrate according to claim 16 or 17, A voltage is applied between the first electrode and the second electrode to vibrate the vibration plate, thereby ejecting liquid from the ejection port. A liquid ejection head characterized by:

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