JP2019048423A - Liquid discharge head, liquid discharge device and piezoelectric device - Google Patents

Abstract

To prevent a piezoelectric body from being broken due to occurrence of stress concentration in the vicinity of a boundary between parts whose thicknesses and shapes are different from each other of a protective layer on an electrode when a piezoelectric device deforms.SOLUTION: A liquid discharge device comprises: a pressure chamber; a piezoelectric element that deforms the pressure chamber; a nozzle for discharging a liquid in the pressure chamber; wiring for applying voltages to the piezoelectric element; and a protective layer covering the piezoelectric element and the wiring. The piezoelectric element comprises: a piezoelectric body layer; a first electrode layer arranged on one surface of the piezoelectric body layer and positioned between the piezoelectric body layer and the pressure chamber; and a second electrode layer arranged on the other surface of the piezoelectric body layer and connected to the wiring in a surface at the opposite side of the piezoelectric body layer. The protective layer has: a first part covering the wiring; a second part covering other configurations without covering the wiring; and a third part, positioned between the first part and the second part, whose surface at the pressure chamber side is flat, which has at least either one of an inclination surface connecting the surface of the first part to the surface of the second part and a plurality of steps on a side opposite to the pressure chamber side.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a piezoelectric device.

Piezoelectric devices are conventionally used in various devices such as liquid discharge heads and barometric pressure sensors. The piezoelectric device includes a piezoelectric layer and electrodes disposed on both sides of the piezoelectric layer, and a voltage is applied by a wire connected to the electrode to be deformed. In the technique of Patent Document 1, a wire is connected to one of the electrodes from the side opposite to the piezoelectric layer. The wiring and its electrode are covered with a protective layer made of Al ₂ O ₃ , ZrO ₂ , Y ₂ O ₃ , Ta ₂ O ₃ , TiO ₂ or the like. The thickness and shape of each part of the protective layer are set according to the performance that each part should achieve. As a result, the shape of the thickness and the outer shape of the part of the protective layer covering the part of the electrode to which the wiring is connected and the other part of the protective layer covering the part of the electrode to which the wiring is not connected It is different.

JP, 2014-179549, A

  At the boundaries between portions of the protective layer on the electrode having different thicknesses and shapes, the ease of deformation of the structure around the piezoelectric device is rapidly changing. Therefore, when the piezoelectric device is deformed by applying a voltage, stress concentration may occur in the vicinity of the boundary and the piezoelectric layer may be broken. The problems of stress concentration and breakage of the piezoelectric layer due to the thickness and shape of the protective layer are not limited to the piezoelectric device that is deformed by application of voltage, and piezoelectric that is deformed by external force and transmits an electrical signal from the electrode The same may occur in devices.

  The present invention has been made to solve at least a part of the above-described problems, and can be realized as the following modes or application examples.

(1) According to one aspect of the present invention, a liquid discharge head is provided. The liquid discharge head includes: a pressure chamber for containing liquid; a piezoelectric element for deforming the pressure chamber; a nozzle for discharging the liquid stored in the pressure chamber; a wire for applying a voltage to the piezoelectric element; And at least one protective layer covering at least a part of the piezoelectric element and the wiring. The piezoelectric element comprises: a piezoelectric layer that deforms when a voltage is applied; a first electrode layer disposed on one surface of the piezoelectric layer and positioned between the piezoelectric layer and the pressure chamber; And a second electrode layer disposed on the other side of the body layer and connected to the wiring on the side opposite to the side where the piezoelectric layer is located. The protective layer comprises: between a first portion covering at least a portion of the wire; a second portion not covering the wire and at least a portion of the other configuration; and between the first portion and the second portion A third portion located on the side opposite to the pressure chamber side, the inclined surface connecting the surface of the first portion and the surface of the second portion, And a third portion having at least one of the plurality of steps.
According to such an aspect, compared to the aspect in which the surface of the first portion covering the wiring and the surface of the second portion covering the other configuration in the protective layer are connected as compared with the aspect in which one step is connected. Stress concentration hardly occurs in the piezoelectric layer at the position of the boundary between the first portion and the second portion. As a result, even if the piezoelectric element is repeatedly deformed, the piezoelectric layer is less likely to be broken as compared with the aspect in which the first portion and the second portion are connected by one step.

(2) In the liquid discharge head according to the above aspect, when projected in a direction perpendicular to the second electrode layer, the third portion is provided in a range in which the pressure chamber is provided. It can also be an aspect.
Among the structures of the piezoelectric element and the periphery thereof, when projected in the direction perpendicular to the second electrode layer, the structure located in the range in which the pressure chamber is provided is at least partially deformed to deform the pressure chamber. There is a high possibility of doing. In the above aspect, the third portion of the protective layer having at least one of the inclined surface and the plurality of steps is disposed in the portion of the piezoelectric element that is likely to be deformed to deform the pressure chamber. For this reason, it is possible to effectively suppress stress concentration in a portion of the piezoelectric element where the possibility of applying stress when deforming the pressure chamber is high.

(3) In the liquid discharge head according to the above aspect, the third portion may cover the part of the second electrode layer without covering the wiring.
In the piezoelectric element, the portion provided with the second electrode layer has a high possibility of being deformed when the pressure chamber is deformed. For this reason, in the above aspect, stress concentration can be effectively suppressed in a portion of the piezoelectric element where the possibility of applying stress when deforming the pressure chamber is high.

(4) The liquid discharge head according to the above aspect, wherein the protective layer includes: a first protective layer covering at least a part of the wiring; and the pressure against the wiring in a direction perpendicular to the second electrode layer A second protective layer disposed on the chamber side and having an insulating property; and an end of the second protective layer is provided with the second electrode layer when projected in a direction perpendicular to the second electrode layer In the range which is being covered, it can also be an aspect covered by the first protective layer.
With such an embodiment, the second protective layer can be peeled off from the structure in which the second protective layer is fixed, as compared with the embodiment in which the end of the second protective layer is not covered by the first protective layer. Can be reduced.

(5) According to another aspect of the present invention, there is provided a liquid ejection apparatus comprising the liquid ejection head of the above aspect.

(6) According to another aspect of the present invention, a piezoelectric device is provided. The piezoelectric device comprises: a piezoelectric element; a wiring for applying a voltage to the piezoelectric element; and one or more protective layers covering at least a part of the piezoelectric element and the wiring. The piezoelectric element comprises: a piezoelectric layer that is deformed by application of a voltage; a first electrode layer disposed on one surface of the piezoelectric layer; and the other surface of the piezoelectric layer; And a second electrode layer connected to the wiring on the side opposite to the side on which the layer is located. The protective layer comprises: between a first portion covering at least a portion of the wire; a second portion not covering the wire and at least a portion of the other configuration; and between the first portion and the second portion A third portion located on the side of the piezoelectric element which is flat and on the opposite side to the piezoelectric element side, and an inclined surface connecting the surface of the first portion and the surface of the second portion And a third portion having at least one of the plurality of steps.

  The plurality of components included in each aspect of the present invention described above are not all essential, and some or all of the effects described in the present specification may be solved in order to solve some or all of the above-described problems. In order to achieve the above, it is possible to appropriately change, delete, replace with another new component, and partially delete limited content for some components of the plurality of components. In addition, in order to solve some or all of the problems described above, or to achieve some or all of the effects described in the present specification, the technical features included in one embodiment of the present invention described above It is also possible to combine some or all of the technical features included in the other aspects of the present invention described above into one independent aspect of the present invention.

  The present invention can also be realized in various forms other than the liquid discharge head, the liquid discharge device, and the piezoelectric device. For example, the present invention can be realized in the form of a manufacturing method or control method of those devices, a computer program for realizing the control method, or a non-temporary recording medium recording the computer program.

It is an explanatory view showing liquid discharge device 100 of a 1st embodiment. FIG. 6 is an exploded perspective view of the liquid discharge head 26. It is explanatory drawing which shows typically the structure of the liquid discharge head 26 in the cross section of the III-III line of FIG. FIG. 8 is a perspective view showing the arrangement of the pressure chamber Ch, the piezoelectric element 38 and the wiring 56 when the liquid discharge head 26 is seen through in the Z direction. It is explanatory drawing which shows typically the structure of the piezoelectric element 38 periphery in the cross section of the VV line | wire of FIG. It is explanatory drawing which shows typically the structure of 2nd Embodiment of the piezoelectric element 38 periphery in the cross section of the VV line | wire of FIG. It is explanatory drawing which shows typically the structure of 3rd Embodiment of the piezoelectric element 38 periphery in the cross section of the VV line | wire of FIG. It is explanatory drawing which shows typically the structure of 4th Embodiment of the piezoelectric element 38 periphery in the cross section of the VV line | wire of FIG.

A. First embodiment:
FIG. 1 is an explanatory view showing a liquid discharge apparatus 100 according to the first embodiment. The liquid ejection apparatus 100 is an ink jet printing apparatus that ejects ink, which is liquid, onto the medium 12. The liquid ejection device 100 can be attached with a liquid container 14 for storing ink, and can set the medium 12. The liquid ejection device 100 can eject the ink in the liquid container 14 toward the medium 12 it can. The liquid ejection apparatus 100 includes a control unit 20, a transport mechanism 22, a moving mechanism 24, and a liquid ejection head 26.

  The liquid discharge head 26 includes a plurality of nozzles Nz. The liquid ejection head 26 ejects the ink supplied from the liquid container 14 from the plurality of nozzles Nz. The ink ejected from the nozzles Nz lands on the medium 12 disposed at a predetermined position. The configuration of the liquid discharge head 26 will be described in detail later.

  The moving mechanism 24 includes an annular belt 244 and a carriage 242 fixed to the belt 244 and capable of holding the liquid discharge head 26. The moving mechanism 24 can reciprocate the liquid discharge head 26 in the X direction by rotating the annular belt 244 in both directions. In FIG. 1, the X direction is indicated by two arrows X1 and X2 in opposite directions.

  The transport mechanism 22 transports the medium 12 along the Y direction during the plurality of movements of the liquid discharge head 26 by the moving mechanism 24. The Y direction is a direction orthogonal to the X direction. As a result, an image is formed on the medium 12 by the ink ejected toward the virtual surface stretched in the X direction and the Y direction. In FIG. 1, the Y direction is indicated by two arrows Y1 and Y2 in opposite directions. The direction indicated by the arrow Y2 is the direction in which the medium 12 is transported.

  Although not shown in FIG. 1, the direction perpendicular to the X direction and the Y direction is taken as the Z direction. The liquid discharge head discharges ink along the Z direction while being recoiled along the X direction. Although not shown in FIG. 1, in the other drawings, in the Z direction, the direction in which the ink is ejected from the liquid ejection head 26 is indicated by an arrow Z1, and the opposite direction is indicated by an arrow Z2.

  The control unit 20 controls the transport mechanism 22, the moving mechanism 24, and the liquid discharge head 26 to form an image on the medium 12.

  FIG. 2 is an exploded perspective view of the liquid discharge head 26. As shown in FIG. The liquid discharge head 26 includes a flow path substrate 32, a pressure chamber substrate 34, a diaphragm 36, a piezoelectric element 38, a housing 42, a sealing body 44, a nozzle plate 46, and a vibration absorbing body 48. Equipped with

  The flow path substrate 32 is a plate-like member having a substantially rectangular outer shape. The flow path substrate 32 includes an opening 322, a supply flow path 324, a communication flow path 326, and a relay flow path 328, which function as part of the ink flow path in the liquid discharge head 26, respectively. In addition, since the relay flow path 328 is provided on the surface of the flow path substrate 32 on the Z1 side, it is not shown in FIG.

  The opening 322 is one through hole extending in the Z direction in the flow path substrate 32. The ink ejected from all the nozzles Nz of the liquid ejection head 26 passes through the opening 322.

  The communication flow channel 326 is a through hole extending in the Z direction in the flow channel substrate 32. The flow path substrate 32 has a plurality of communication flow paths 326. The plurality of communication channels 326 are provided side by side in the Y direction on the X1 side with respect to the opening 322. One communication channel 326 is connected to one of the plurality of nozzles Nz of the liquid discharge head 26. The number of communication channels 326 and the number of nozzles Nz provided in the liquid discharge head 26 coincide with each other. The ink ejected from each nozzle Nz of the liquid ejection head 26 passes through the corresponding communication channel 326.

  The supply flow path 324 is a through hole extending in the Z direction in the flow path substrate 32. The flow path substrate 32 includes a plurality of supply flow paths 324. One supply flow path 324 is connected to one of the plurality of nozzles Nz provided in the liquid discharge head 26 via a pressure chamber Ch described later and the communication flow path 326 described above. The number of supply channels 324 and the number of nozzles Nz provided in the liquid discharge head 26 coincide with each other. Each supply flow channel 324 is provided between the common opening 322 and the communication flow channel 326 to which each supply flow channel 324 is connected. The ink ejected from each nozzle Nz of the liquid ejection head 26 passes through the corresponding supply channel 324.

  Although not shown in FIG. 2, the relay flow path 328 is a recess provided on the surface of the flow path substrate 32 on the Z1 side. The relay flow path 328 connects the opening 322 and the plurality of supply flow paths 324 on the surface of the flow path substrate 32 on the Z1 side. The ink ejected from each nozzle Nz of the liquid ejection head 26 passes through the relay flow path 328.

  The pressure chamber substrate 34 is a plate-like member having a substantially rectangular outer shape. The pressure chamber substrate 34 is disposed on the Z2 side with respect to the flow passage substrate 32. More specifically, the pressure chamber substrate 34 is disposed so as to cover a part of the flow path substrate 32 and the area where the supply flow path 324 and the communication flow path 326 are provided. The pressure chamber substrate 34 has a plurality of openings 342.

  The openings 342 are a plurality of through holes extending in the Z direction in the pressure chamber substrate 34. The respective openings 342 are disposed at overlapping positions when projected in the Z direction with a pair of communication channels 326 and supply channels 324 which are arranged in the channel substrate 32 in the X direction. Each opening 342 is connected to the pair of communication flow channel 326 and supply flow channel 324. The number of openings 342 and the number of nozzles Nz provided in the liquid discharge head 26 coincide with each other. The opening 342 functions as a pressure chamber Ch that contains the ink and applies pressure to the ink in the flow path in the liquid ejection head 26.

  The diaphragm 36 is a plate-like member having an outer shape that matches the pressure chamber substrate 34. The diaphragm 36 is disposed on the Z2 side with respect to the pressure chamber substrate 34. The diaphragm 36 is disposed such that the outer shape of the diaphragm 36 and the outer shape of the pressure chamber substrate 34 match when projected in the Z direction. The vibration plate 36 functions as an inner wall that closes the Z2 side of the opening 342 of the pressure chamber substrate 34. The diaphragm 36 is configured to be elastically deformed by the piezoelectric element 38.

  The piezoelectric element 38 is disposed on the Z 2 side with respect to the diaphragm 36. More specifically, one piezoelectric element 38 is provided at a position overlapping the one opening 342 of the pressure chamber substrate 34 with the diaphragm 36 interposed therebetween. The piezoelectric element 38 is bonded to the diaphragm 36 via an adhesive layer (not shown). The number of piezoelectric elements 38 and the number of nozzles Nz provided in the liquid discharge head 26 coincide with each other. Each piezoelectric element 38 is applied with a voltage through the wiring substrate 50 to be deformed, thereby deforming the diaphragm 36 that constitutes the inner wall of each opening 342 (that is, each pressure chamber Ch). As a result, the pressure chamber Ch is deformed and pressure is applied to the ink in the pressure chamber Ch. The wiring substrate 50 is omitted in FIG. 2 in order to facilitate understanding of the technology.

  The sealing body 44 is disposed on the Z 2 side with respect to the diaphragm 36 and the piezoelectric element 38. More specifically, the sealing body 44 is disposed so as to cover a part of the area of the diaphragm 36 and the area where the piezoelectric element 38 is provided. The sealing body 44 is provided with one recess on the surface on the Z1 side. The plurality of piezoelectric elements 38 disposed on the vibration plate 36 are accommodated in the recess. Each piezoelectric element 38 can be deformed in the recess of the sealing body 44 when a voltage is applied. The sealing body 44 functions to protect the piezoelectric element 38 and to reinforce the mechanical strength of the pressure chamber substrate 34 and the diaphragm 36.

  The housing portion 42 is disposed on the Z2 side with respect to the flow path substrate 32. More specifically, the housing 42 is disposed so as to cover a part of the flow path substrate 32 and the area where the opening 322 is provided. The housing portion 42 is disposed on the X2 side with respect to the sealing body 44, the diaphragm 36, and the pressure chamber substrate 34. The housing portion 42 includes a housing portion 422 and an introduction port 424.

  The housing portion 422 is a single recess that is open to the Z1 side. The housing portion 422 is not shown in FIG. 2 because it is provided on the inside of the housing portion 42 and the surface on the Z1 side. The housing portion 422 is disposed at an overlapping position with the opening 322 of the flow path substrate 32 when projected in the Z direction. The housing portion 422 is connected to the opening 322.

  The introduction port 424 is a through hole extending in the Z direction, and is connected to the housing portion 422. The introduction port 424 is disposed substantially at the center in the X direction and the Y direction on the surface on the Z 2 side of the housing unit 42.

  The nozzle plate 46 is disposed on the Z1 side with respect to the flow path substrate 32. More specifically, the nozzle plate 46 is disposed so as to cover a part of the flow path substrate 32 and an area where the communication flow path 326 is provided. The nozzle plate 46 includes a plurality of nozzles Nz. Each nozzle Nz is disposed at a position overlapping with each communication channel 326 of the channel substrate 32. Each nozzle Nz is connected to each communication channel 326. Each nozzle Nz discharges the ink stored in the pressure chamber Ch.

  The vibration absorbing body 48 is disposed on the Z 2 side with respect to the flow path substrate 32. More specifically, the vibration absorber 48 is a partial region of the flow path substrate 32, and the opening 322, the relay flow path 328 (not shown in FIG. 2), and the supply flow path 324 are provided. It is arranged to cover the area. The vibration absorber 48 functions as an inner wall that closes the opening 322, the relay flow path 328, and the Z1 side of the supply flow path 324. The vibration absorbing body 48 is configured to be elastically deformed in response to the pressure of the ink inside the opening 322, the relay flow path 328, and the supply flow path 324, and to reduce the pressure change.

  FIG. 3 is an explanatory view schematically showing a configuration of the liquid discharge head 26 in a cross section taken along line III-III in FIG. FIG. 3 is a cross-sectional view taken along the inlet port 424 of the housing 42 shown in FIG. 2, the opening 342 (pressure chamber Ch) of the pressure chamber substrate 34, the supply passage 324 of the passage substrate 32, the communication passage 326, and so on. The cross section of the liquid discharge head 26 by-Z plane is shown. In FIG. 3, the wiring substrate 50 omitted in FIG. 2 is shown.

  Wiring substrate 50 is a circuit substrate on which a plurality of wires for electrically connecting control unit 20 (see FIG. 1) and a power supply circuit (not shown in FIGS. 1 to 3) and liquid discharge head 26 are formed. It is. A drive signal for driving the piezoelectric element 38 is supplied from the wiring substrate 50 to each piezoelectric element 38. As the wiring substrate 50, for example, a flexible substrate such as a flexible printed circuit (FPC) or a flexible flat cable (FFC) can be employed.

The diaphragm 36 includes an elastic layer 361 disposed on the pressure chamber Ch side and an insulating layer 362 disposed on the piezoelectric element 38 side. The elastic layer 361 is an elastic film formed of an elastic material such as silicon oxide (SiO ₂ ). The insulating layer 362 is an insulating film formed of an insulating material such as zirconium oxide (ZrO ₂ ).

  The ink supplied to the liquid discharge head 26 is introduced into the housing portion 422 from the introduction port 424, passes through the opening 322, the relay flow path 328, and the supply flow path 324, and is introduced to the pressure chamber Ch (opening 342). be introduced. In addition, the space comprised by the accommodating part 422 and the opening part 322 is also called liquid storage chamber Rs. The ink supplied from the inlet port 424 and supplied to each nozzle Nz of the liquid discharge head 26 is stored in the liquid storage chamber Rs.

  The supply flow channel 324, the pressure chamber Ch, the piezoelectric element 38, and the communication flow channel 326 are provided one by one for one nozzle Nz. The ink supplied from the supply flow path 324 to the pressure chamber Ch is pressed through the diaphragm 36 by the piezoelectric element 38 to which a voltage is applied. Then, the ink in the pressure chamber Ch is discharged from the nozzle Nz through the communication flow path 326. The ink in the pressure chamber Ch is discharged to the outside of the liquid discharge head 26, and thereafter, as the diaphragm 36 returns to a flat plate shape, the ink is introduced into the liquid storage chamber Rs (the housing portion 422 and the opening 322) from the introduction port 424. Ink is newly supplied.

  FIG. 4 is a perspective view showing the arrangement of the pressure chamber Ch, the piezoelectric element 38 and the wiring 56 when the liquid discharge head 26 is seen through in the Z direction. FIG. 4 shows a configuration around the three piezoelectric elements 38 among the plurality of piezoelectric elements 38 provided in the liquid discharge head 26. In FIG. 4, the protective layer 60 covering the piezoelectric element 38 and the wiring 56 is not shown to facilitate understanding of the technology.

  The pressure chamber Ch has an oblong shape whose dimension in the X direction is larger than the dimension in the Y direction. The wiring 56 is disposed at a position overlapping a part including the end on the X2 side of the pressure chamber Ch. The piezoelectric element 38 includes a first electrode layer 51, a piezoelectric layer 52, and a second electrode layer 53.

  The first electrode layer 51 is a conductive layer provided on the insulating layer 362 of the diaphragm 36 and having a substantially uniform thickness. The first electrode layer 51 is bonded to the diaphragm 36 via the adhesion layer. The first electrode layer 51 is disposed on the insulating layer 362 of the diaphragm 36 so as to cover a region in which the plurality of pressure chambers Ch are provided. The first electrode layer 51 is shared by the plurality of piezoelectric elements 38. However, in the present specification, since the function of being deformed by the deformation of the piezoelectric layer 52 described later is individually exhibited by each piezoelectric element 38, the liquid discharge head 26 includes the “plurality of piezoelectric elements 38”. Describe as things.

  The first electrode layer 51 is also present in a region overlapping with the wiring 56, that is, on the Z1 side with respect to the wiring 56. The first electrode layer 51 is connected to the wiring of the wiring substrate 50 (see FIG. 3) at an end portion in the Y1 direction not shown in FIG. The first electrode layer 51 is supplied with a drive signal Vbs from a circuit provided on the wiring substrate 50.

  The piezoelectric layer 52 is a layer provided on the first electrode layer 51 and having a substantially uniform thickness. The piezoelectric layer 52 is made of a piezoelectric material such as lead zirconate titanate (PZT). The piezoelectric layer 52 is provided on the first electrode layer 51 in a region where the pressure chamber Ch is provided. Specifically, the piezoelectric layer 52 has an oblong shape whose dimension in the X direction is larger than the dimension in the Y direction. The piezoelectric layer 52 is applied with a voltage from the first electrode layer 51 and the second electrode layer 53, and is deformed in the Z1 direction (the direction toward the back of the sheet in FIG. 4).

  The second electrode layer 53 is a conductive layer provided on the piezoelectric layer 52 and having a substantially uniform thickness. The second electrode layer 53 is provided in the region where the piezoelectric layer 52 is provided. Specifically, the second electrode layer 53 has an oblong shape whose dimension in the X direction is larger than the dimension in the Y direction. The second electrode layer 53 is connected to the wiring 56 on the surface on the Z2 side in the vicinity of the end on the X2 side. A contact hole of the protective layer 62 where the second electrode layer 53 and the wiring 56 are connected is shown as H2 in FIG.

  Since each of the first electrode layer 51, the piezoelectric layer 52, and the second electrode layer 53 has a substantially uniform thickness, the piezoelectric element 38 is in the Z direction in the range in which the second electrode layer 53 is provided. It has a substantially uniform thickness. The surface of the second electrode layer 53 on the Z2 side (the front side in the drawing of FIG. 4) is flat.

  The wiring 56 is disposed to overlap a part of the second electrode layer 53 including the end on the X2 side of the second electrode layer 53. The wiring 56 is disposed so as to also overlap the first electrode layer 51 and the piezoelectric layer 52. However, the wiring 56 and the first electrode layer 51 and the piezoelectric layer 52 are insulated by a protective layer 62 (not shown in FIG. 4) described later. On the other hand, the wiring 56 and the second electrode layer 53 are electrically connected through the contact hole H2 provided in the protective layer 62.

  The wiring 56 is connected to the wiring board 50 (see FIG. 3) at a portion which does not appear in FIG. The wiring 56 is supplied with a drive signal Vdr from a circuit provided on the wiring substrate 50. The piezoelectric layer 52 is deformed by the potential difference between the drive signal Vdr supplied to the second electrode layer 53 via the wiring 56 and the drive signal Vbs supplied to the first electrode layer 51, and the piezoelectric element 38 is driven. Be done. That is, the wiring 56 applies a voltage (that is, a potential difference between the drive signal Vdr and the drive signal Vbs) to the piezoelectric element 38.

  FIG. 5 is an explanatory view schematically showing the configuration around the piezoelectric element 38 in the cross section taken along the line V-V in FIG. As described above, on the Z2 side of the diaphragm 36, the first electrode layer 51, the piezoelectric layer 52 and the second electrode layer 53 of the piezoelectric element 38 are disposed in that order. That is, the first electrode layer 51 is disposed on the Z1 side surface of the piezoelectric layer 52, and is located between the piezoelectric layer 52 and the pressure chamber Ch. The second electrode layer 53 is disposed on the Z2 side surface of the piezoelectric layer 52, and is connected to the wiring 56 on the side (Z2 side) opposite to the side on which the piezoelectric layer 52 is located.

  In the liquid discharge head 26 of the present embodiment, protective layers 61 and 62 are provided on each piezoelectric element 38. The protective layer 62 is configured to cover the first electrode layer 51, the piezoelectric layer 52, and the second electrode layer 53 except for the contact hole H2 in which the piezoelectric layer 52 and the wiring 56 communicate with each other. The protective layer 61 is formed to cover the wire 56 formed on the protective layer 62. The protective layers 61 and 62 are collectively referred to as a protective layer 60.

  The protective layer 60 is formed of an insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx). The protective layer 60 has a function of insulating the first electrode layer 51 and the piezoelectric layer 52 from the wiring 56. The protective layer 60 also has a function of protecting the wiring 56, the first electrode layer 51, the piezoelectric layer 52, and the second electrode layer 53 from the outside air.

  The protective layer 60 does not cover the wiring 56 in the concave portion of the sealing body 44 (see FIG. 3), and the first electrode layer 51, the piezoelectric layer 52, and the second electrode layer 53 without covering the wiring 56. And a second portion P2 covering the The thickness in the Z direction of the second portion P2 (protective layer 62) covering the second electrode layer 53 is 100 nm or less. With such a configuration, the second portion P2 of the protective layer 60 can sufficiently follow the deformation of the piezoelectric element 38. That is, the extent to which the second portion P2 of the protective layer 60 inhibits the deformation of the piezoelectric element 38 can be sufficiently reduced. Further, the durability of the second portion P2 of the protective layer 60, which is repeatedly subjected to the force due to the deformation of the piezoelectric element 38, can be sufficiently improved.

  The protective layer 60 further has a third portion P3 at a position between the first portion P1 and the second portion P2 in the X direction. The surface P3p on the pressure chamber Ch side (Z1 side) of the third portion P3 is parallel to the surface on the Z2 side of the second electrode layer 53 and is flat. More specifically, in the present embodiment, the surface P3p on the Z1 side of the third portion P3 is in contact with the surface on the Z2 side of the second electrode layer 53. However, another layer may be provided between the surface P3 p and the second electrode layer 53.

  In the third portion P3, that the surface P3p on the pressure chamber Ch side is "flat" means that the size of the unevenness of the surface P3p is the unevenness or level difference of the external shape on the Z2 side of the third portion P3. It means that it is 1/10 or less of the size. The size of the unevenness of the surface is the direction of the direction perpendicular to the second electrode layer (Z direction) between two points farthest in the direction (Z direction) perpendicular to the second electrode layer in the surface. It is a distance (so-called Ry).

  The third portion P3 is a surface (surface on the Z2 side) P1s of the first portion P1 and a surface (surface on the Z2 side) P2s of the second portion P2 on the side (Z2 side) opposite to the pressure chamber Ch side. An outer shape including steps C11, C12, and C13 to be connected is provided. The steps C11, C12 and C13 are arranged in the X2 direction in that order. The outer shape of the protective layer 60 is a shape in which the height in the Z2 direction is increased each time the steps C11, C12, and C13 are exceeded as it proceeds in the X2 direction. The steps C11, C12, and C13 are provided closer to the X1 side than the wiring 56.

  The step C11 is provided on the surface of the protective layer 62 on the Z2 side in the range in which the second electrode layer 53 is provided when projected in the Z direction. The step C12 is formed on the surface of the protective layer 62 on the Z2 side by the end on the X1 side of the protective layer 61. The step C13 is provided on the surface of the protective layer 61 on the Z2 side in the range in which the second electrode layer 53 is provided when projected in the Z direction.

  The third portion P3 provided with the steps C11, C12, and C13 is provided in the range in which the pressure chamber Ch and the second electrode layer 53 are provided when projected in the Z direction. The second portion P2 and the third portion P3 do not cover the wiring 56 in the Z direction and cover a part of the second electrode layer 53. These shapes of the protective layer 60 can be realized by forming the protective layer 62, thereafter forming the protective layer 62, further forming the protective layer 61, and then forming the protective layer 61. . The formation of the protective layers 61 and 62 may be performed collectively.

  The protective layer 60 does not include the third portion P3 having the plurality of steps C11, C12, and C13 as in the present embodiment, and the surface P1s of the first portion P1 and the surface P2s of the second portion P2 are one step Cc1. Can also be configured to connect. Such an embodiment is shown in FIG. 5 by dashed lines. However, in such an embodiment, the ease (rigidity) of deformation when the piezoelectric element 38 is deformed in the Z direction when a voltage is applied changes rapidly at the step Cc1 in the X direction. Therefore, when the piezoelectric element 38 is deformed by applying a voltage, stress concentration may occur in the piezoelectric layer 52 in the vicinity of the step Cc1, and the piezoelectric layer 52 may be broken.

  However, in the present embodiment, between the first portion P1 and the second portion P2 of the protective layer 60, a plurality of steps C11, C12, C13 connecting the first portion P1 and the second portion P2 having different thicknesses. A third portion P3 including the is provided. For this reason, the ease of the elastic deformation (rigidity) of the configuration around the piezoelectric element 38 changes little by little at the positions of the steps C11, C12 and C13 in the X direction. Therefore, compared to the aspect in which the first portion P1 and the second portion P2 are connected by one step Cc1, the portion in the piezoelectric layer 52 is at a portion between the first portion P1 and the second portion P2. Excessive stress concentration is unlikely to occur at one point. As a result, even if the piezoelectric element 38 is repeatedly deformed, the piezoelectric layer 52 is unlikely to be broken.

  Further, in the present embodiment, when projected in the direction (Z direction) perpendicular to the second electrode layer 53, the third portion P3 of the protective layer 60 is provided within the range in which the pressure chamber Ch is provided. ing. That is, the third portion P3 of the protective layer having the plurality of steps C11, C12, and C13 is disposed in a portion that is deformed to deform the pressure chamber Ch when discharging the ink. Therefore, stress concentration can be effectively suppressed in a portion to which stress is applied when deforming the pressure chamber Ch.

  And in this embodiment, the 3rd portion P3 which has a plurality of level differences C11, C12, and C13 does not cover wiring 56, and has covered a part of 2nd electrode layer 53. Then, in the piezoelectric element 38, when the pressure chamber Ch is deformed, the portion where the second electrode layer 53 is provided is deformed so as to be convex in the Z1 direction. For this reason, in the present embodiment, as compared with the aspect in which the third portion P3 is provided in the portion covering the wiring 56 in the protective layer 60, it is effective in the portion to which stress is applied when deforming the pressure chamber Ch. Stress concentration can be suppressed.

B. Second embodiment:
FIG. 6 is an explanatory view schematically showing the configuration of the second embodiment around the piezoelectric element 38 in the cross section taken along the line V-V in FIG. In the configuration around the piezoelectric element 38 according to the second embodiment, protective layers 61b, 62b, 63b are provided instead of the protective layers 61, 62 (see FIG. 5). The other points of the second embodiment are the same as the first embodiment.

  The protective layer 63 b is configured to cover the first electrode layer 51, the piezoelectric layer 52, and the second electrode layer 53 except for the contact holes H 2 in which the piezoelectric layer 52 and the wiring 56 communicate with each other. The protective layer 62 b is provided on the protective layer 63 b in a region where the wiring 56 is located when projected in the Z direction. The protective layer 62b is a partial region including the end on the X2 side of the second electrode layer 53, and is provided in a region including the periphery of the contact hole H2 provided in the protective layer 63b. On the other hand, when projected in the Z direction, the end of the protective layer 62b on the X1 side is located on the surface on the Z2 side of the protective layer 63b in the region where the second electrode layer 53 is provided (see FIG. 6 C21). The protective layer 61 b is formed on the protective layer 62 b so as to cover the wiring 56 formed on the protective layer 62 b.

  The protective layers 61b, 62b and 63b are collectively referred to as a protective layer 60b. The protective layer 60 b also exhibits the same function as the protective layer 60. That is, the protective layer 60 b functions to insulate the first electrode layer 51 and the piezoelectric layer 52 from the wiring 56. The protective layer 60 b also has a function of protecting the wiring 56, the first electrode layer 51, the piezoelectric layer 52, and the second electrode layer 53 from the open air.

  The protective layer 60 b includes a first portion P 1 covering a part of the wiring 56 in the recess of the sealing body 44, and the first electrode layer 51, the piezoelectric layer 52 and the second electrode layer 53 without covering the wiring 56. And a second portion P2 covering a portion. The thickness in the Z direction of the second portion P2 (protective layer 63b) covering the second electrode layer 53 is 100 nm or less. With such a configuration, the second portion P2 of the protective layer 60b can sufficiently follow the deformation of the piezoelectric element 38.

  The protective layer 60b further has a third portion P3 between the first portion P1 and the second portion P2. The surface P3p on the pressure chamber Ch side (Z1 side) of the third portion P3 is parallel to the surface on the Z2 side of the second electrode layer 53 and is flat. In the present embodiment, the surface P3p on the Z1 side of the third portion P3 is in contact with the surface on the Z2 side of the second electrode layer 53. The third portion P3 has steps C21, C22, and C23 connecting the surface P1s of the first portion P1 and the surface P2s of the second portion P2 on the side (Z2 side) opposite to the pressure chamber Ch side. The steps C21, C22 and C23 are arranged in the X2 direction in that order. The outer shape of the protective layer 60b is a shape in which the height in the Z2 direction is increased each time the steps C21, C22, and C23 are exceeded as the X2 direction is advanced. The steps C21, C22, and C23 are provided closer to the X1 side than the wiring 56.

  The step C21 is formed on the surface on the Z2 side of the protective layer 63b by the end on the X1 side of the protective layer 62b. The step C22 is formed on the surface on the Z2 side of the protective layer 62b by the end on the X1 side of the protective layer 61b. The step C23 is provided on the surface on the Z2 side of the protective layer 61b.

  The third portion P3 including the steps C21, C22, and C23 is provided in the range in which the pressure chamber Ch and the second electrode layer 53 are provided when projected in the Z direction. The second portion P <b> 2 and the third portion P <b> 3 do not cover the wiring 56 and cover a part of the second electrode layer 53.

  A configuration in which the first portion P1 and the second portion P2 are connected by one step Cc2 without providing the third portion P3 having the plurality of steps C21, C22, C23 as in the present embodiment in the protective layer 60b. You can also. Such an embodiment is shown in FIG. 6 by a dashed line. However, in such an embodiment, when the piezoelectric element 38 is deformed by applying a voltage, stress concentration may occur in the piezoelectric layer 52 in the vicinity of the step Cc2, and the piezoelectric layer 52 may be broken. .

  In the present embodiment, a third portion P3 including a plurality of steps C21, C22, and C23 connecting the first portion P1 and the second portion P2, which have different thicknesses, between the first portion P1 and the second portion P2. Is provided. For this reason, compared with the aspect in which the first portion P1 and the second portion P2 are connected by one step Cc2, the piezoelectric layer 52 is formed at the position of the boundary between the first portion P1 and the second portion P2. Excessive stress concentration is unlikely to occur at one point. As a result, even if the piezoelectric element 38 is repeatedly deformed, the piezoelectric layer 52 is unlikely to be broken.

  Also in the present embodiment, when projected in the direction (Z direction) perpendicular to the second electrode layer 53, the third portion P3 of the protective layer 60 is provided within the range in which the pressure chamber Ch is provided. ing. The third portion P3 does not cover the wiring 56 and partially covers the second electrode layer 53. For this reason, also in the present embodiment, it is possible to effectively suppress stress concentration in a portion to which stress is applied when deforming the pressure chamber Ch.

  Further, in the present embodiment, no step (see C11 in FIG. 5) is formed in the protective layer 63b on the second electrode layer 53, and the end of the protective layer 62b provided on the protective layer 63b is used. , And a step C21 is formed. For this reason, after forming the protective layer 63b, it is not necessary to perform removal processing (here, etching) in order to form a step in the protective layer 63b.

C. Third embodiment:
FIG. 7 is an explanatory view schematically showing the configuration of the third embodiment around the piezoelectric element 38 in the cross section along the line V-V in FIG. 4. In the configuration around the piezoelectric element 38 of the third embodiment, protective layers 61c and 62c are provided in place of the protective layers 61b and 62b (see FIG. 6) of the second embodiment. The other points of the third embodiment are the same as the second embodiment.

  The shape of the end portion on the X1 side of the protective layers 61c and 62c is different from the shape of the portion on the X1 side of the protective layers 61b and 62b (see FIG. 6). At each end of the protective layers 61c and 62c on the X1 side, instead of the steps C21 and C22, the surface on the Z2 side of the protective layer 61c (the surface of the step C23) and the surface on the Z2 side of the protective layer 63b are An inclined surface SL is provided so as to monotonously increase in the Z2 direction as it proceeds in the X2 direction. In the present specification, “a monotonically increasing in a direction D (as advancing in a certain direction) a certain plane or line” means that the plane or the line is opposite to the direction D when viewed along a certain direction. It does not contain the component of the direction of. That is, the surface or line may include a portion (a non-increased portion) extending in a direction perpendicular to the direction D in part. The inclined surface SL can be in the form of a plane or a side surface of a truncated cone. In the present embodiment, the inclined surface SL is a plane.

  The angle θ formed by the inclined surface SL with respect to the surface P2s of the second portion P2 (the surface on the Z2 side of the protective layer 63b) is 50 degrees or less in the present embodiment. The angle θ between the inclined surface SL and the surface P2s of the second portion P2 is the angle of the portion where the protective layer 62c is present in the XZ cross section. The inclined surface SL is provided in the range in which the second electrode layer 53 is provided when projected in the Z direction. The step C23 is provided in the protective layer 61c in the same manner as the second embodiment (see FIGS. 6 and 7). The other points of the protective layers 61 c and 62 c are the same as the protective layers 61 b and 62 b of the second embodiment.

  The protective layers 61c, 62c and 63b are collectively referred to as a protective layer 60c. The protective layer 60 c also exhibits the same function as the protective layer 60. The protective layer 60 c has a first portion P 1 covering a part of the wiring 56 in the concave portion of the sealing body 44, and the first electrode layer 51, the piezoelectric layer 52 and the second electrode layer 53 without covering the wiring 56. And a second portion P2 covering a portion. The protective layer 60c further includes a third portion P3 between the first portion P1 and the second portion P2.

  The surface P3p on the pressure chamber Ch side (Z1 side) of the third portion P3 is parallel to the surface on the Z2 side of the second electrode layer 53 and is flat. In the present embodiment, the surface P3p on the Z1 side of the third portion P3 is in contact with the surface on the Z2 side of the second electrode layer 53. The third portion P3 has an inclined surface SL and a step C23 connecting the surface P1s of the first portion P1 and the surface P2s of the second portion P2 on the side (Z2 side) opposite to the pressure chamber Ch side. The inclined surface SL and the step C23 are arranged in that order in the X2 direction. The outer shape of the protective layer 60c is a shape in which the height in the Z2 direction becomes higher each time it goes over the inclined surface SL and the step C23 as it proceeds in the X2 direction. The inclined surface SL and the step C23 are provided closer to the X1 side than the wiring 56.

  The third portion P3 provided with the inclined surface SL and the step C23 is provided in the range in which the pressure chamber Ch and the second electrode layer 53 are provided when projected in the Z direction. The second portion P <b> 2 and the third portion P <b> 3 do not cover the wiring 56 and cover a part of the second electrode layer 53.

  These shapes of the protective layer 60c can be realized by forming and forming the protective layers 61c, 62c, 63b by lamination and etching. For example, the inclined surface SL can be formed by setting the end face shape of the mask covering a portion not removed during etching as follows. That is, in etching, the end face shape of the mask covering the portion not to be removed is inclined so as to become thinner toward the portion to be removed, and the upper end portion of the inclination is further projected to the surface of the mask Do.

  In the present embodiment, between the first portion P1 and the second portion P2, the third portion P3 having the inclined surface SL connecting the first portion P1 and the second portion P2 different in thickness and the step C23 is It is provided. For this reason, the boundary between the first portion P1 and the second portion P2 compared to the aspect in which the first portion P1 and the second portion P2 are connected by one step Cc2 (shown by a broken line in FIG. 7) In the above position, excessive stress concentration hardly occurs at one point of the piezoelectric layer 52. In particular, stress concentration does not occur in the piezoelectric layer 52 in the portion where the inclined surface SL is provided in the X direction. As a result, even if the piezoelectric element 38 is repeatedly deformed, the piezoelectric layer 52 is unlikely to be broken.

D. Fourth Embodiment:
FIG. 8 is an explanatory view schematically showing the configuration of the fourth embodiment around the piezoelectric element 38 in the cross section taken along the line V-V in FIG. 4. In the piezoelectric element 38 of the fourth embodiment, protective layers 61d and 62d are provided in place of the protective layers 61b and 62b (see FIG. 6) of the second embodiment. The other points of the fourth embodiment are the same as the second embodiment.

  The protective layer 62 d is provided on the protective layer 63 b and in a region where the wiring 56 is located when projected in the Z direction. The insulating protective layer 62d is disposed on the pressure chamber Ch side with respect to the wiring 56 in the Z direction, that is, on the first electrode layer 51 side, so that the wiring 56 and the first electrode layer 51 are insulated. Ru.

  In addition, the protective layer 62d is a partial region including the end on the X2 side of the second electrode layer 53 when projected in the Z direction, and includes the periphery of the contact hole H2 provided in the protective layer 63b. It is provided in the area. On the other hand, the end 62de on the X1 side of the protective layer 62d is located on the surface on the Z2 side of the protective layer 63b in the region where the second electrode layer 53 is provided when projected in the Z direction.

  The protective layer 61 d is formed on the protective layer 62 d so as to cover the wiring 56 formed on the protective layer 62 d. Further, the protective layer 61d covers the end 62de on the X1 side of the protective layer 62d within the range in which the second electrode layer 53 is provided, when projected in the Z direction.

  With such a configuration, the end 62de on the X1 side of the protective layer 62d is not covered by the protective layer 61d, and the end on the X1 side of the protective layer 61d (see C41) and X1 on the protective layer 62d Each layer of the protective layer 60d is repeatedly peeled off due to repeated deformation, oxidation, and the like compared to the aspect in which both the side end portions 62de are exposed to the air, thereby reducing the possibility of the function of the protective layer 60d being reduced. can do.

  The protective layers 61d, 62d and 63b are collectively referred to as a protective layer 60d. The protective layer 60 d also exhibits the same function as the protective layer 60. The protective layer 60 d includes a first portion P1 covering a part of the wiring 56 in the recess of the sealing body 44, and the first electrode layer 51, the piezoelectric layer 52, and the second electrode layer 53 without covering the wiring 56. And a second portion P2 covering a portion. The protective layer 60d further has a third portion P3 between the first portion P1 and the second portion P2.

  The surface P3p on the pressure chamber Ch side (Z1 side) of the third portion P3 is parallel to the surface on the Z2 side of the second electrode layer 53 and is flat. In the present embodiment, the surface P3p on the Z1 side of the third portion P3 is in contact with the surface on the Z2 side of the second electrode layer 53. The third portion P3 has steps C41, C42, and C43 connecting the surface P1s of the first portion P1 and the surface P2s of the second portion P2 on the side (Z2 side) opposite to the pressure chamber Ch side. The steps C41, C42 and C43 are arranged in the X2 direction in that order. The outer shape of the protective layer 60d is such that the height in the Z2 direction becomes higher each time it goes over the steps C41, C42, and C43 as it proceeds in the X2 direction. The steps C41, C42, and C43 are provided closer to the X1 side than the wiring 56.

  The step C41 is formed on the surface on the Z2 side of the protective layer 63b by the end on the X1 side of the protective layer 61d. The steps C42 and C43 are provided on the surface on the Z2 side of the protective layer 61d.

  The third portion P3 including the steps C41, C42, and C43 is provided in the range in which the pressure chamber Ch and the second electrode layer 53 are provided when projected in the Z direction. The second portion P <b> 2 and the third portion P <b> 3 do not cover the wiring 56 and cover a part of the second electrode layer 53.

  In the present embodiment, a third portion P3 having a plurality of steps C41, C42, and C43 connecting the first portion P1 and the second portion P2, which have different thicknesses, between the first portion P1 and the second portion P2. Is provided. For this reason, the boundary between the first portion P1 and the second portion P2 compared to the aspect in which the first portion P1 and the second portion P2 are connected by one step Cc2 (shown by a broken line in FIG. 8) In the above position, excessive stress concentration hardly occurs at one point of the piezoelectric layer 52. As a result, even if the piezoelectric element 38 is repeatedly deformed, the piezoelectric layer 52 is unlikely to be broken.

  In the present specification, the protective layer 61 d is also referred to as a “first protective layer”. The protective layer 62 d is also referred to as a “second protective layer”.

E. Other forms:
E1. Other form 1:
(1) In the said embodiment, protective layer 60, 60b-60d is comprised by two layers or three layers (refer FIGS. 5-8). However, for example, in the configuration in which the first electrode layer is insulated from the wiring connected to the second electrode layer and the second electrode layer by a configuration other than the protective layer, the protective layer may be configured as one layer. . The protective layer may be composed of four or more layers, such as five or six layers. When the protective layer is composed of a plurality of layers, the plurality of layers may be connected to each other or separated from each other.

(2) In the above embodiment, the piezoelectric element 38 is deformed to be convex toward the pressure chamber Ch when a voltage is applied, and is flat when no voltage is applied. It is configured. However, the piezoelectric element may be in the form of a flat plate when a voltage is applied, and may have another shape when a voltage is not applied. That is, the piezoelectric element may be any one that can be deformed by the presence or absence of application of a voltage. The deformation of the piezoelectric element does not matter if it is bending deformation or distortion deformation. Further, in the piezoelectric element, one set of electrodes for deforming the piezoelectric layer may be provided independently, or as illustrated in the above embodiment (see FIG. 4), one of the other piezoelectric elements is It may be shared with the electrode.

(3) In the above embodiment, the first portions P1 of the protective layers 60 and 60b to 60d cover the wiring 56 in the recess of the sealing body 44 (see FIGS. 5 to 8). However, the first portion of the protective layer may not cover a part of the wiring connected to the second electrode in the recess of the sealing body. In addition, the first portion of the protective layer may not cover a portion of the wiring connected to the second electrode (for example, a connection portion with the wiring substrate) outside the sealing body.

(4) In the above embodiment, the second portion P2 of the protective layers 60, 60b to 60d does not cover the wiring 56 in the recess of the sealing body 44, and the first electrode layer 51, the piezoelectric layer 52, and the second And the electrode layer 53 (see FIGS. 5 to 8). However, the second portion of the protective layer may not cover part of the first electrode layer 51, the piezoelectric layer 52, and the second electrode layer 53 in the recess of the sealing body. In addition, the second portion of the protective layer is a part of the first electrode layer 51, the piezoelectric layer 52, and the second electrode layer 53 outside the sealing body (for example, a connection portion between the first electrode layer and the wiring substrate ) May not be covered.

(5) In the above embodiment, the material constituting the protective layer is silicon oxide (SiOx), silicon nitride (SiNx) or the like. However, the protective layer material can also be made of other materials such as Al ₂ O ₃ , ZrO ₂ , Y ₂ O ₃ , Ta ₂ O ₃ and TiO ₂ . However, in the technology disclosed in the present specification, the material forming the protective layer is a material that is less likely to be elastically deformed than the materials forming the first electrode layer, the piezoelectric layer, and the second electrode layer. Especially effective.

(6) In the third embodiment, the protective layer 60c has one inclined surface SL and one step C23 (see FIG. 7). However, the protective layer may have a plurality of inclined surfaces. In addition to the plurality of steps, one or more slopes may be provided. In addition, the plurality of steps and the one or more slopes may be arranged in any order.

E2. Other form 2:
In the above embodiment, when projected in the direction (Z direction) perpendicular to the second electrode layer 53, the third portions P3 of the protective layers 60, 60b to 60d are within the range in which the pressure chamber Ch is provided. Provided (see FIGS. 5-8). However, for example, in the aspect in which the second electrode layer is provided beyond the range in which the pressure chamber is provided, and the wiring is connected to the second electrode layer outside the range in which the pressure chamber is provided. The first part of the protective layer and at least a part of the third part may be provided outside the range in which the pressure chamber is provided.

E3. Other form 3:
In the above embodiment, the third portions P3 of the protective layers 60 and 60b to 60d do not cover the wiring 56 and cover a part of the second electrode layer 53 in the Z direction. However, the third portion of the protective layer may cover a part of the wiring connected to the second electrode layer. For example, when projected in a direction (Z direction) perpendicular to the second electrode layer, the surface of the first portion and the surface of the second portion are connected monotonically increasing from the surface of the second portion to the surface of the first portion A part of the step or the inclined surface may be disposed at a position overlapping with the wiring connected to the second electrode layer.

E4. Other form 4:
(1) In the fourth embodiment, the protective layer 62d is provided on the protective layer 63b (see FIG. 8). However, in the embodiment of FIG. 8, an embodiment without the protective layer 63b may be employed. In such an embodiment, the protective layer 61 d covers the wiring 56 and also covers the protective layer 62 d on the second electrode layer 53, the second electrode layer 53, the piezoelectric layer 52, and the first electrode layer 51. It can be done.

(2) In the fourth embodiment, the protective layer 61d covers the end 62de on the X1 side of the protective layer 62d within the range in which the second electrode layer 53 is provided (see FIG. 8). However, the first protective layer on the Z2 side may not cover the end of the second protective layer on the Z1 side within the range in which the second electrode layer is provided. In addition, the first protective layer may cover the end of the second protective layer outside the range where the second electrode layer is provided, or may not cover the end of the second protective layer. . The first protective layer may cover at least a part of the end of the second protective layer.

E5. Another form 5:
In the above embodiment, the liquid discharge head 26 and the liquid container 14 are connected by a predetermined ink flow path, and the liquid container 14 is not transported by the moving mechanism 24. However, the liquid discharge head and the liquid container may be integrally formed, and may be moved by the moving mechanism. The technology disclosed herein can also be applied to a liquid discharge head unit in which such a liquid discharge head and a liquid container are fixed to each other.

E6. Other embodiment 6:
In the above embodiment, the technology disclosed in the present specification has been described using the liquid discharge head 26 and the liquid discharge device 100 as an example. However, the technology disclosed in the present specification is not limited to the liquid discharge head and the liquid discharge device, and a wire is connected to an electrode disposed on one surface of the flat plate with respect to a piezoelectric element configured in a flat plate shape. Can be applied to various piezoelectric devices.

  For example, the technology disclosed in this specification can be applied to an ultrasonic transducer that vibrates a piezoelectric element to generate an ultrasonic wave, or an ultrasonic sensor that vibrates a piezoelectric element by an ultrasonic wave to generate a signal. . In addition, the technology disclosed in the present specification can be applied to a liquid feeding pump that feeds liquid by moving a piezoelectric element. The technology disclosed herein can be applied to a MEMS motor that rotates a rotor by vibration due to a piezoelectric element. Furthermore, the technology disclosed herein can also be applied to an air pressure sensor in which the piezoelectric element is deformed by environmental pressure to transmit a signal.

E7. Other:
The present invention is not limited to the above-described embodiments, examples, and modifications, and can be implemented with various configurations without departing from the scope of the invention. For example, technical features in the embodiments, examples, and modifications corresponding to the technical features in the respective forms described in the section of the summary of the invention can be provided to solve some or all of the problems described above, or In order to achieve part or all of the above-described effects, replacements or combinations can be made as appropriate. Also, if the technical features are not described as essential in the present specification, they can be deleted as appropriate.

  12: medium; 14: liquid container; 20: control unit; 22: transport mechanism; 24: moving mechanism; 26: liquid discharge head; 32: flow path substrate; 34: pressure chamber substrate; 36: diaphragm; 38: piezoelectric Element: 42: Case part: 44: Sealed body: 46: Nozzle plate; 48: Vibration absorber; 50: Wiring substrate; 51: First electrode layer; 52: Piezoelectric layer; 53: Second electrode layer; 60, 60b to 60d: protective layer; 61, 61b to 61d: protective layer; 62, 62b to 62d: protective layer; 62de: end of protective layer; 63b: protective layer; 100: liquid discharge device; ........................ 424 ... introduction port; C11 to C13 ... level difference; C 1 to C23: step; C41, C42: step; Cc1, Cc2: step; Ch: pressure chamber; H2: contact hole; Nz: nozzle; P1: first portion; P1s: first portion surface; P2: second Part: P2s: Surface of the second part P3: Third part P3: Surface of the third part on the second electrode side Rs: Liquid storage chamber SL: Sloped surface: Vbs: Drive signal: Vdr: Drive signal X1, X2: Arrows indicating the X direction (moving direction of the carriage); Y1, Y2: Arrows indicating the Y direction (medium conveying direction); Z1, Z2 ... Arrows indicating the Z direction (ink ejection direction); θ: The angle that the inclined surface SL makes with the surface P2s of the second portion P2.

Claims (6)

A liquid discharge head,
A pressure chamber for containing liquid,
A piezoelectric element that deforms the pressure chamber;
A nozzle for discharging the liquid contained in the pressure chamber;
A wire for applying a voltage to the piezoelectric element;
And at least one protective layer covering at least a part of the piezoelectric element and the wiring;
The piezoelectric element is
A piezoelectric layer that is deformed by applying a voltage;
A first electrode layer disposed on one surface of the piezoelectric layer and positioned between the piezoelectric layer and the pressure chamber;
And a second electrode layer disposed on the other side of the piezoelectric layer and connected to the wiring on the side opposite to the side where the piezoelectric layer is located,
The protective layer is
A first portion covering at least a part of the wiring;
A second portion that does not cover the wiring and covers at least a portion of another configuration;
A third portion located between the first portion and the second portion and having a flat surface on the pressure chamber side, and a surface opposite to the pressure chamber side, the surface of the first portion and A liquid discharge head comprising: an inclined surface connecting the surface of the second portion; and a third portion having at least one of a plurality of steps. The liquid discharge head according to claim 1, wherein
When projected in a direction perpendicular to the second electrode layer, the third portion is provided in a range in which the pressure chamber is provided. The liquid discharge head according to claim 1 or 2, wherein
The liquid discharge head according to claim 1, wherein the third portion does not cover the wiring and partially covers the second electrode layer. The liquid discharge head according to any one of claims 1 to 3, wherein
The protective layer is
A first protective layer covering at least a part of the wiring;
And a second protective layer disposed on the pressure chamber side with respect to the wiring and having an insulating property in a direction perpendicular to the second electrode layer,
An end portion of the second protective layer is covered with the first protective layer in a range in which the second electrode layer is provided when projected in a direction perpendicular to the second electrode layer. Discharge head.   A liquid discharge apparatus comprising the liquid discharge head according to any one of claims 1 to 4. A piezoelectric device,
A piezoelectric element,
A wire for applying a voltage to the piezoelectric element;
And at least one protective layer covering at least a part of the piezoelectric element and the wiring;
The piezoelectric element is
A piezoelectric layer that is deformed by applying a voltage;
A first electrode layer disposed on one surface of the piezoelectric layer;
And a second electrode layer disposed on the other side of the piezoelectric layer and connected to the wiring on the side opposite to the side where the piezoelectric layer is located,
The protective layer is
A first portion covering at least a part of the wiring;
A second portion that does not cover the wiring and covers at least a portion of another configuration;
A third portion located between the first portion and the second portion, the surface on the side of the piezoelectric element being flat, and on the opposite side to the side of the piezoelectric element, the surface of the first portion and A piezoelectric device comprising: an inclined surface connecting the surface of the second portion; and a third portion having at least one of a plurality of steps.

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