Liquid injection head, liquid injection device, and piezoelectric device

Abstract

To solve the problem that in an arm part of a diaphragm, it is hard to suppress a decrease in vibration efficiency while maintaining reliability of a diaphragm.SOLUTION: A diaphragm 50 includes a first layer 51 including silicon as a constituent element, a second layer 52 including metallic elements other than zirconium as a constituent element, and a third layer 53 containing zirconium as a constituent element. When, of the diaphragm 50, an area overlapping a pressure chamber 12 seen in a first direction and overlapping a first electrode 60, a piezoelectric layer 70, and a second electrode 80 is an active region A1 and, of the diaphragm 50, an area overlapping the pressure chamber 12 seen in the first direction and not overlapping the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is a non-active region A2, the diaphragm 50 has a first layer 51, a second layer 52, and a third layer 53 in the active region A1, and has the first layer 51 and the second layer 52 and does not have the third layer 53 in at least a part of the non-active region A2.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a liquid ejection head and a liquid ejection device having a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode, a diaphragm that vibrates by driving the piezoelectric element, and a pressure chamber substrate that partitions a pressure chamber that applies pressure to a liquid by vibration of the diaphragm, and also relates to a piezoelectric device having a piezoelectric element and a diaphragm.

Background Art

[0002] As a liquid ejection head which is one type of electronic device, an inkjet recording head is known. The inkjet recording head includes a pressure chamber substrate provided with a pressure chamber communicating with a nozzle, a diaphragm provided on one surface side of the pressure chamber substrate, and a piezoelectric element provided on the diaphragm, and causes a pressure change in the ink in the pressure chamber by driving the piezoelectric element to eject ink droplets from the nozzle.

[0003] Here, there are various configurations of the diaphragm. For example, there is a diaphragm including an elastic film containing silicon as a constituent element and an insulating film containing zirconium as a constituent element. For example, there is a diaphragm composed of a laminate of a first vibration layer (elastic film) formed of silicon oxide (SiO2) and a second vibration layer (insulating film) formed of zirconium oxide (ZrO2) (see Patent Document 1).

[0004] Furthermore, Patent Document 1 discloses a configuration in which a second part of the second vibration layer is removed, that is, a configuration in which the second vibration layer is removed while leaving the first vibration layer in the arm portion of the diaphragm. By removing the second vibration layer in the arm portion of the diaphragm in this way, it is possible to improve the displacement amount of the diaphragm while maintaining the strength of the diaphragm.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] However, if the diaphragm is configured to remove the insulating film while leaving the elastic film in the arm portion as described above, the following problems may arise.

[0007] If the insulating film is completely removed from the arms of the diaphragm, there is a risk that over-etching may remove part of the elastic film, reducing the reliability of the diaphragm. On the other hand, if the insulating film is not completely removed and is left at a predetermined thickness, the reduction in diaphragm reliability is suppressed, but sufficient displacement of the diaphragm may not be obtained, potentially reducing vibration efficiency. As described above, there are various problems with the configuration of the arms of the diaphragm from the standpoint of reliability and vibration efficiency.

[0008] It should be noted that this problem is not limited to liquid ejection heads, such as those used in inkjet recording heads, but also exists in other piezoelectric devices. [Means for solving the problem]

[0009] One aspect of the present invention that solves the above problems comprises a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction, a diaphragm that vibrates by driving the piezoelectric element, and a pressure chamber substrate that partitions a pressure chamber that applies pressure to a liquid by the vibration of the diaphragm, wherein the pressure chamber substrate, the diaphragm, and the piezoelectric element are stacked in this order in the first direction, the diaphragm includes a first layer containing silicon as a constituent element, a second layer disposed between the first layer and the piezoelectric layer and containing a metallic element other than zirconium as a constituent element, and a third layer disposed between the second layer and the piezoelectric layer and containing zirconium as a constituent element, wherein the diaphragm overlaps with the pressure chamber when viewed in the first direction, and the first electrode, the piezoelectric layer, and the second electrode all of The region overlapping with the first electrode, the piezoelectric layer and the second electrode are defined as the active region, and of the diaphragm, the region overlapping with the pressure chamber when viewed in the first direction is defined as the active region, and the region overlapping with the first electrode, the piezoelectric layer and the second electrode. at least one of the followingWhen the region that does not overlap with the active region is defined as the non-active region, the diaphragm has the first layer, the second layer, and the third layer in the active region, and has the first layer and the second layer, and the third layer in at least a part of the non-active region. Furthermore, in at least a portion of the non-active region that does not have the third layer, the second layer of the diaphragm is laminated adjacent to the second electrode, the second electrode contains the metal element contained in the second layer, and the second layer contains an oxide of the metal element. The liquid spray head is characterized by the following features. Another aspect of the present invention includes a piezoelectric element comprising a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction, a diaphragm that vibrates by driving the piezoelectric element, and a pressure chamber substrate that partitions a pressure chamber that applies pressure to a liquid by the vibration of the diaphragm, wherein the pressure chamber substrate, the diaphragm, and the piezoelectric element are stacked in this order in the first direction, and the diaphragm comprises a first layer containing silicon as a constituent element, a second layer disposed between the first layer and the piezoelectric layer and containing a metallic element other than zirconium as a constituent element, and a third layer disposed between the second layer and the piezoelectric layer and containing zirconium as a constituent element, wherein the diaphragm overlaps with the pressure chamber when viewed in the first direction, and the first electrode, the piezoelectric layer and the front The liquid spray head is characterized in that, when the region overlapping with the entirety of the second electrode is defined as the active region, and the region of the diaphragm that overlaps with the pressure chamber when viewed in the first direction and does not overlap with at least one of the first electrode, the piezoelectric layer, and the second electrode is defined as the inactive region, the diaphragm has the first layer, the second layer, and the third layer in the active region, the first layer and the second layer in at least a part of the inactive region and does not have the third layer, and in at least a part of the inactive region that does not have the third layer, the second layer of the diaphragm is laminated adjacent to the second electrode, the second electrode contains the metal element contained in the second layer, and the second layer contains a nitride of the metal element.

[0010] Another aspect of the present invention is a liquid injection device characterized by comprising the liquid injection head of the above aspect.

[0011] Another aspect of the present invention includes a substrate having a recess, a piezoelectric element comprising a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction, and a diaphragm that vibrates by driving the piezoelectric element, wherein the substrate, the diaphragm, and the piezoelectric element are stacked in this order in the first direction, and the diaphragm comprises a first layer containing silicon as a constituent element, a second layer disposed between the first layer and the piezoelectric layer and containing a metallic element other than zirconium as a constituent element, and a third layer disposed between the second layer and the piezoelectric layer and containing zirconium as a constituent element, wherein the diaphragm overlaps with the recess when viewed in the first direction, and the first electrode, the piezoelectric layer, and the second electrode all of The region overlapping with the first electrode, the piezoelectric layer and the second electrode are defined as the active region, and of the diaphragm, the region overlapping with the recess when viewed in the first direction is defined as the active region, and the region overlapping with the first electrode, the piezoelectric layer and the second electrode. at least one of When the region that does not overlap with the active region is defined as the non-active region, the diaphragm has the first layer, the second layer, and the third layer in the active region, and has the first layer and the second layer, and the third layer in at least a part of the non-active region. Furthermore, in at least a portion of the non-active region that does not have the third layer, the second layer of the diaphragm is laminated adjacent to the second electrode, the second electrode contains the metal element contained in the second layer, and the second layer contains an oxide of the metal element. The piezoelectric device is characterized by the following features. Another aspect of the present invention includes a substrate having a recess, a piezoelectric element comprising a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction, and a diaphragm that vibrates by driving the piezoelectric element, wherein the substrate, the diaphragm, and the piezoelectric element are stacked in this order in the first direction, and the diaphragm comprises a first layer containing silicon as a constituent element, a second layer disposed between the first layer and the piezoelectric layer and containing a metallic element other than zirconium as a constituent element, and a third layer disposed between the second layer and the piezoelectric layer and containing zirconium as a constituent element, wherein the diaphragm has a region that overlaps with the recess when viewed in the first direction and overlaps with all of the first electrode, the piezoelectric layer, and the second electrode. The piezoelectric device is characterized in that, when a region is defined as the active region, and a region of the diaphragm that overlaps with the recess when viewed in the first direction and does not overlap with at least one of the first electrode, the piezoelectric layer, and the second electrode is defined as the inactive region, the diaphragm has the first layer, the second layer, and the third layer in the active region, the first layer and the second layer in at least a part of the inactive region and does not have the third layer, and in at least a part of the inactive region that does not have the third layer, the second layer of the diaphragm is laminated adjacent to the second electrode, the second electrode contains the metal element contained in the second layer, and the second layer contains a nitride of the metal element. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of an inkjet recording device according to Embodiment 1. [Figure 2]It is an exploded perspective view of a recording head according to Embodiment 1. [Figure 3] It is a plan view of a recording head according to Embodiment 1. [Figure 4] It is a cross-sectional view of a recording head according to Embodiment 1. [Figure 5] It is a cross-sectional view of a recording head according to Embodiment 1. [Figure 6] It is a cross-sectional view of a recording head according to Embodiment 2. [Figure 7] It is a cross-sectional view of a recording head according to Embodiment 3.

Mode for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described in detail based on embodiments. However, the following description is for one aspect of the present invention, and the configuration of the present invention can be arbitrarily changed within the scope of the invention.

[0014] Also, in each figure, X, Y, and Z represent three spatial axes orthogonal to each other. In this specification, the directions along these axes are referred to as the X direction, the Y direction, and the Z direction. The direction in which the arrow in each figure points is the positive (+) direction, and the opposite direction of the arrow is the negative (-) direction. Also, the Z direction indicates the vertical direction, the +Z direction indicates vertically downward, and the -Z direction indicates vertically upward. Furthermore, for the three spatial axes X, Y, and Z without limiting the positive and negative directions, they will be described as the X axis, the Y axis, and the Z axis.

[0015] (Embodiment 1) FIG. 1 is a diagram showing a schematic configuration of an inkjet recording apparatus 1 according to Embodiment 1 of the present invention. First, the overall configuration of the inkjet recording apparatus 1 according to the present embodiment will be described.

[0016] The inkjet recording apparatus (hereinafter simply referred to as the "recording apparatus") 1 shown in FIG. 1 is an example of a liquid ejection apparatus, and is a printing apparatus that ejects ink, which is a kind of liquid, as ink droplets onto a medium S such as printing paper and causes landing, and performs printing such as an image by an arrangement of dots formed on the medium S. As the medium S, in addition to recording paper, any material such as a resin film or cloth can be used.

[0017] As shown in FIG. 1, the recording apparatus 1 includes an inkjet recording head (hereinafter also simply referred to as the "recording head") 2, a liquid container 3, a control unit 4 that is a control unit, a conveyance mechanism 5 that feeds out the medium S, and a moving mechanism 6.

[0018] Although the recording head 2 will be described in detail later, the recording head 2 ejects ink supplied from the liquid container 3 onto the medium S from a plurality of nozzles.

[0019] The liquid container 3 stores a plurality of types (for example, a plurality of colors) of ink ejected from the recording head 2 individually. Examples of the liquid container 3 include a cartridge that is detachable from the recording apparatus 1, a bag-shaped ink pack formed of a flexible film, and an ink tank that can be refilled with ink. The liquid container 3 stores a plurality of types of ink having different colors, components, and the like.

[0020] The control unit 4 includes, for example, a control device such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and a storage device such as a semiconductor memory. The control unit 4 comprehensively controls each element of the recording apparatus 1, that is, the recording head 2, the conveyance mechanism 5, the moving mechanism 6, etc. by the control device executing a program stored in the storage device.

[0021] The conveying mechanism 5 conveys the medium S in the X-axis direction and has conveying rollers 7. That is, the conveying mechanism 5 conveys the medium S in the X-axis direction by the rotation of the conveying rollers 7. The conveying mechanism 5 that conveys the medium S is not limited to one equipped with conveying rollers 7, but may also convey the medium S by a belt or drum, for example.

[0022] The moving mechanism 6 is a mechanism for moving the recording head 2 back and forth along the Y-axis, and comprises a transport body 8 and a transport belt 9. The transport body 8 is a roughly box-shaped structure, a so-called carriage, that houses the recording head 2 and is fixed to the transport belt 9. The transport belt 9 is an endless belt installed along the Y-axis. Under the control of the control unit 4, the transport belt 9 rotates, causing the recording head 2 to reciprocate along the Y-axis with the transport body 8. The transport body 8 may also be configured to carry a liquid container 3 together with the recording head 2.

[0023] Under the control of the control unit 4, the recording head 2 performs an ejection operation in which ink supplied from the liquid container 3 is ejected as ink droplets from each of its multiple nozzles onto the medium S in the +Z direction. This ejection operation by the recording head 2 is performed in parallel with the transport of the medium S by the transport mechanism 5 and the reciprocating movement of the recording head 2 by the moving mechanism 6, thereby forming an image on the surface of the medium S, in other words, printing is performed.

[0024] Figure 2 is an exploded perspective view of the recording head according to this embodiment, and Figure 3 is a plan view of the recording head, illustrating the schematic configuration of the piezoelectric element. Figure 4 is a cross-sectional view of the recording head, corresponding to line AA in Figure 3. Figure 5 is a cross-sectional view illustrating the configuration of the diaphragm and piezoelectric element, corresponding to line BB in Figure 3.

[0025] As shown in the figure, the recording head 2 according to this embodiment includes a pressure chamber substrate 10. The pressure chamber substrate 10 is made of, for example, a silicon substrate, a glass substrate, an SOI substrate, or various ceramic substrates.

[0026] The pressure chamber substrate 10 has pressure chambers 12, which are recesses, arranged in a line along the X-axis direction. Multiple pressure chambers 12 are arranged on a straight line along the X-axis direction such that their positions in the Y-axis direction are the same. Pressure chambers 12 adjacent to each other in the X-axis direction are separated by partition walls 11. Of course, the arrangement of the pressure chambers 12 is not particularly limited. For example, the arrangement of multiple pressure chambers 12 arranged in the X-axis direction may be a so-called staggered arrangement, where each pressure chamber 12 is shifted by one in the Y-axis direction.

[0027] Furthermore, the pressure chamber 12 in this embodiment is formed in a rectangular shape, for example, where the length in the Y-axis direction is longer than the length in the X-axis direction when viewed from the +Z direction in a plan view. Of course, the shape of the pressure chamber 12 when viewed from the +Z direction in a plan view is not particularly limited and may be a parallelogram, polygon, circle, oval, etc. Note that the oval shape referred to here is a shape based on a rectangle with semicircular ends in the longitudinal direction, and includes rounded rectangles, ellipses, egg shapes, etc.

[0028] On the +Z direction side of the pressure chamber substrate 10, the communication plate 15, the nozzle plate 20, and the compliance substrate 45 are sequentially stacked.

[0029] The communication plate 15 is provided with a nozzle communication passage 16 that connects the pressure chamber 12 and the nozzle 21. The communication plate 15 is also provided with a first manifold section 17 and a second manifold section 18 that constitute part of a manifold 100, which is a common liquid chamber through which multiple pressure chambers 12 are connected. The first manifold section 17 is provided penetrating the communication plate 15 in the Z-axis direction. The second manifold section 18 is provided opening on the +Z side surface without penetrating the communication plate 15 in the Z-axis direction.

[0030] Furthermore, the connecting plate 15 is provided with an independent supply passage 19 for each of the pressure chambers 12, which communicates with one end of the pressure chamber 12 in the Y-axis direction. The supply passage 19 connects the second manifold section 18 to each pressure chamber 12, supplying ink from the manifold 100 to each pressure chamber 12.

[0031] As the connecting plate 15, a silicon substrate, glass substrate, SOI substrate, various ceramic substrates, metal substrate, etc., can be used.

[0032] The nozzle plate 20 is provided on the side of the communication plate 15 opposite to the pressure chamber substrate 10, that is, on the +Z direction side. Nozzles 21 are formed on the nozzle plate 20, which communicate with each pressure chamber 12 via nozzle communication passages 16.

[0033] In this embodiment, the multiple nozzles 21 are provided corresponding to each pressure chamber 12 and are arranged in a line along the X-axis. The nozzle plate 20 has two rows of these multiple nozzles 21 arranged in the Y-axis direction. That is, the multiple nozzles 21 in each row are arranged so that they are at the same position in the Y-axis direction. The arrangement of the nozzles 21 is not particularly limited. For example, the nozzles 21 arranged in a line along the X-axis direction may be arranged with every other nozzle offset in the Y-axis direction.

[0034] The material of the nozzle plate 20 is not particularly limited, and for example, silicon substrates, glass substrates, SOI substrates, various ceramic substrates, and metal substrates can be used. Examples of metal plates include stainless steel substrates. Furthermore, organic materials such as polyimide resin can also be used as the material of the nozzle plate 20.

[0035] The compliance substrate 45 is provided together with the nozzle plate 20 on the side of the communication plate 15 opposite to the pressure chamber substrate 10, i.e., on the +Z direction side. This compliance substrate 45 is provided around the nozzle plate 20 and seals the openings of the first manifold section 17 and the second manifold section 18 provided on the communication plate 15. In this embodiment, the compliance substrate 45 comprises a sealing film 46 made of a flexible thin film and a fixed substrate 47 made of a hard material such as metal. The region of the fixed substrate 47 facing the manifold 100 is an opening 48 that is completely removed in the thickness direction. Therefore, one side of the manifold 100 is a compliance section 49 sealed only by the flexible sealing film 46.

[0036] On the other hand, on the side of the pressure chamber substrate 10 opposite to the nozzle plate 20, etc., that is, the side in the -Z direction, a diaphragm 50 and a piezoelectric element 300 are provided, which will be described in more detail later, to cause a pressure change in the ink in the pressure chamber 12 by bending and deforming the diaphragm 50.

[0037] A protective substrate 30, having approximately the same size as the pressure chamber substrate 10, is further bonded to the -Z-direction side of the pressure chamber substrate 10. The protective substrate 30 has a holding portion 31, which is a space for protecting the piezoelectric elements 300. The holding portion 31 is provided independently for each row of piezoelectric elements 300 arranged in the X-axis direction, and two of them are formed side by side in the Y-axis direction. In addition, the protective substrate 30 has a through hole 32 that penetrates in the Z-axis direction between the two holding portions 31 arranged side by side in the Y-axis direction.

[0038] Furthermore, a case member 40 is fixed to the protective substrate 30, which together defines a manifold 100 communicating with multiple pressure chambers 12, along with the pressure chamber substrate 10. The case member 40 has substantially the same shape as the communication plate 15 described above in plan view, and is joined to the protective substrate 30 as well as to the communication plate 15 described above.

[0039] Such a case member 40 has a housing section 41 on the side of the protective substrate 30 that is a space with a depth capable of accommodating the pressure chamber substrate 10 and the protective substrate 30. This housing section 41 has an opening area larger than the surface of the protective substrate 30 that is joined to the pressure chamber substrate 10. When the pressure chamber substrate 10 and the protective substrate 30 are housed in the housing section 41, the opening surface of the housing section 41 on the nozzle plate 20 side is sealed by a communication plate 15.

[0040] Furthermore, the case member 40 has third manifold sections 42 defined on both outer sides of the housing section 41 in the Y-axis direction. The manifold 100 is composed of the first manifold section 17 and the second manifold section 18 provided on the communication plate 15, and the third manifold section 42. The manifold 100 is provided continuously along the X-axis direction, and the supply passages 19 connecting each pressure chamber 12 to the manifold 100 are arranged side by side in the X-axis direction.

[0041] Furthermore, the case member 40 is provided with an inlet 44 that communicates with the manifold 100 and supplies ink to each manifold 100. In addition, the case member 40 is provided with a connection port 43 that communicates with the through hole 32 of the protective substrate 30 and through which the wiring board 120 is inserted.

[0042] In this embodiment of the recording head 2, ink is drawn in from an inlet 44 connected to an external ink supply means (not shown), and the inside is filled with ink from the manifold 100 to the nozzles 21. Then, according to the recording signal from the drive circuit 121, a voltage is applied to each piezoelectric element 300 corresponding to the pressure chamber 12. As a result, the diaphragm 50 bends and deforms together with the piezoelectric element 300, increasing the pressure in each pressure chamber 12, and ink droplets are ejected from each nozzle 21.

[0043] The configuration of the diaphragm 50 and piezoelectric element 300 according to this embodiment will be described below. As described above, the diaphragm 50 and piezoelectric element 300 are provided on the -Z direction side of the pressure chamber substrate 10. That is, the pressure chamber substrate 10, the diaphragm 50 and the piezoelectric element 300 are stacked in this order in the first direction, the Z axis direction.

[0044] The piezoelectric element 300 is a pressure generating means that causes a pressure change in the ink in the pressure chamber 12 and is also called a piezoelectric actuator. This piezoelectric element 300 comprises a first electrode 60, a piezoelectric body layer 70, and a second electrode 80, which are sequentially stacked from the +Z direction side (which is the diaphragm 50 side) toward the -Z direction.

[0045] Of the piezoelectric element 300, the portion of the piezoelectric layer 70 that experiences piezoelectric strain when a voltage is applied between the first electrode 60 and the second electrode 80 is referred to as the active portion 310. Conversely, the portion of the piezoelectric layer 70 that does not experience piezoelectric strain is referred to as the inactive portion. In other words, of the piezoelectric element 300, the portion of the piezoelectric layer 70 sandwiched between the first electrode 60 and the second electrode 80 is the active portion 310, and the portion of the piezoelectric layer 70 not sandwiched between the first electrode 60 and the second electrode 80 is the inactive portion.

[0046] Generally, one of the first electrode 60 or the second electrode 80 is configured as an individual electrode independent of each active part 310, and the other electrode is configured as a common electrode common to multiple active parts 310. In this embodiment, the first electrode 60 constitutes an individual electrode, and the second electrode 80 constitutes a common electrode.

[0047] Specifically, the first electrode 60 is divided into individual electrodes for each pressure chamber 12, making each active portion 310 independent. The first electrode 60 is formed with a width narrower than the width of the pressure chamber 12 in the X-axis direction. That is, in the X-axis direction, the end of the first electrode 60 is located inside the region facing the pressure chamber 12.

[0048] In the Y-axis direction, the end of the first electrode 60 on the nozzle 21 side is located outside the pressure chamber 12, away from the region facing the pressure chamber 12. On the other hand, the end of the first electrode 60 opposite to the nozzle 21 is located in the region facing the pressure chamber 12.

[0049] The material of the first electrode 60 is not particularly limited, but can be any conductive material, such as iridium (Ir), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), chromium (Cr), nickel-chromium (NiCr), tungsten (W), titanium (Ti), or titanium oxide (TiO2). X ), titanium tungsten (TiW), etc. can be used.

[0050] The piezoelectric layer 70 is provided continuously along the X-axis direction with a predetermined length in the Y-axis direction. That is, the piezoelectric layer 70 is provided continuously along the parallel arrangement direction of the pressure chambers 12 with a predetermined thickness. The thickness of the piezoelectric layer 70 is not particularly limited, but it is formed to a thickness of about 1 to 4 μm. Furthermore, the length of the piezoelectric layer 70 in the Y-axis direction is longer than the length in the Y-axis direction, which is the longitudinal direction of the pressure chamber 12, and the piezoelectric layer 70 extends to both outer sides of the pressure chamber 12 in the Y-axis direction.

[0051] In this embodiment, the end of the piezoelectric layer 70 opposite to the nozzle 21 is located outside the end of the first electrode 60. That is, the end of the first electrode 60 opposite to the nozzle 21 is covered by the piezoelectric layer 70. Also, the end of the piezoelectric layer 70 on the nozzle 21 side is located inside the end of the first electrode 60, and the end of the first electrode 60 on the nozzle 21 side is exposed and not covered by the piezoelectric layer 70.

[0052] Furthermore, grooves 71 are formed in the piezoelectric layer 70 at positions corresponding to each partition wall 11. The grooves 71 penetrate the piezoelectric layer 70 in the Z-axis direction, which is the thickness direction. However, the grooves 71 may not penetrate the piezoelectric layer 70 in the Z-axis direction, but may only extend partway through the thickness direction of the piezoelectric layer 70. That is, a portion of the piezoelectric layer 70 may remain at the bottom surface of the groove 71.

[0053] Furthermore, the width of the groove 71 in the X-axis direction is the same as or wider than the width of the partition wall 11. In this embodiment, the width of the groove 71 in the X-axis direction is wider than the width of the partition wall 11. Therefore, the end of the piezoelectric layer 70 in the X-axis direction defined by the groove 71 is located inside the pressure chamber 12. As a result, the rigidity of the portion of the diaphragm 50 facing both ends of the pressure chamber 12 in the X-axis direction, the so-called arm portion of the diaphragm 50, is suppressed, making it easier to displace the piezoelectric element 300.

[0054] Furthermore, the end of the first electrode 60 in the X-axis direction is covered by the piezoelectric layer 70. In other words, the end of the piezoelectric layer 70 in the X-axis direction, defined by the groove 71, is located inside the pressure chamber 12 and outside the end of the first electrode 60.

[0055] Such a piezoelectric layer 70 is constructed using a piezoelectric material consisting of a composite oxide with a perovskite structure represented by the general formula ABO3. In this embodiment, lead zirconate titanate (PZT; Pb(Zr,Ti)O3) is used as the piezoelectric material. By using PZT as the piezoelectric material, a piezoelectric layer 70 with a relatively large piezoelectric constant d31 can be obtained.

[0056] In the perovskite composite oxide represented by the general formula ABO3, oxygen atoms are 12-coordinate at the A site and 6-coordinate at the B site, forming an octahedron. In this embodiment, lead (Pb) is located at the A site, and zirconium (Zr) and titanium (Ti) are located at the B site.

[0057] Piezoelectric materials are not limited to the above-mentioned PZT. Other elements may be present at the A and B sites. For example, the piezoelectric material may be a perovskite material such as barium zirconate titanate (Ba(Zr,Ti)O3), lead lanthanum zirconate titanate ((Pb,La)(Zr,Ti)O3), lead zirconium magnesium niobate titanate (Pb(Zr,Ti)(Mg,Nb)O3), or lead zirconate titanate niobate titanate containing silicon (Pb(Zr,Ti,Nb)O3).

[0058] In addition, piezoelectric materials may be materials with reduced Pb content, so-called low-lead materials, or materials that do not use Pb, so-called lead-free materials. Using low-lead materials as piezoelectric materials can reduce the amount of Pb used. Also, using lead-free materials as piezoelectric materials eliminates the need for Pb. Therefore, using low-lead or lead-free materials as piezoelectric materials can reduce the environmental burden. Examples of lead-free piezoelectric materials include BFO-based materials containing bismuth ironate (BFO; BiFeO3) and KNN-based materials containing potassium sodium niobate (KNN; KNaNbO3).

[0059] The second electrode 80 is provided continuously on the -Z direction side of the piezoelectric layer 70, opposite to the first electrode 60, and constitutes a common electrode common to multiple active parts 310. The second electrode 80 is provided continuously along the X direction with a predetermined length in the Y direction. The second electrode 80 is also provided on the inner surface of the groove 71, that is, on the side surface of the groove 71 of the piezoelectric layer 70 and on the diaphragm 50 which is the bottom surface of the groove 71. Of course, the second electrode 80 may be provided only on a part of the inner surface of the groove 71, or not on the entire inner surface of the groove 71.

[0060] The material of the second electrode 80 is not particularly limited, but precious metal materials such as iridium (Ir), platinum (Pt), palladium (Pd), and gold (Au), and conductive oxides such as lanthanum nickel oxide (LNO) can be used. The second electrode 80 may also be made of multiple materials stacked together, in which case it is preferable to use a material for the second electrode 80 that contains iridium (Ir) and titanium (Ti).

[0061] Furthermore, individual lead electrodes 91, which are lead wires, are drawn out from the first electrode 60, and a common lead electrode 92, which is a lead wire, is drawn out from the second electrode 80. A flexible wiring board 120 is connected to these individual lead electrodes 91 and common lead electrode 92 at the ends opposite to the piezoelectric element 300. In this embodiment, the individual lead electrodes 91 and common lead electrode 92 are extended so as to be exposed within through holes 32 formed in the protective substrate 30, and are electrically connected to the wiring board 120 within these through holes 32. A drive circuit 121 having a switching element for driving the piezoelectric element 300 is mounted on the wiring board 120.

[0062] As shown in Figure 5, the diaphragm 50 includes a first layer 51, a second layer 52, and a third layer 53, which are stacked in this order in the -Z direction. Specifically, the first layer 51 is the layer located furthest to the +Z direction of the diaphragm 50 and is in contact with the pressure chamber substrate 10, the third layer 53 is the layer located furthest to the -Z direction of the diaphragm 50 and is in contact with the piezoelectric element 300, and the second layer 52 is the layer located between the first layer 51 and the third layer 53.

[0063] In Figure 5, etc., the interfaces between the layers constituting the diaphragm 50 are clearly shown, but these interfaces do not necessarily have to be clearly defined. For example, the constituent materials of two adjacent layers may be mixed near the interface between them.

[0064] The first layer 51 is provided across the entire surface of the pressure chamber substrate 10 and contains silicon (Si) as a constituent element. Specifically, the first layer 51 is an elastic film composed of, for example, silicon oxide (SiO2). The method for forming the first layer 51 is not particularly limited, but the first layer 51 is formed, for example, by thermal oxidation of the surface of the pressure chamber substrate 10. The silicon in the first layer 51 may exist in the form of an oxide, or it may exist in the form of elemental silicon, nitride, or oxynitride.

[0065] The third layer 53, as will be described in detail later, is not provided across the entire surface of the pressure chamber substrate 10, but is provided in a predetermined area and contains zirconium (Zr) as a constituent element. Specifically, the third layer 53 is an insulating film formed of zirconium oxide (ZrO2), for example. The method for forming the third layer 53 is not particularly limited, but the third layer 53 is formed, for example, by forming a layer of elemental zirconium using a sputtering method, and then thermally oxidizing the layer. The zirconium in the third layer 53 may exist in the form of an oxide, or it may exist in the form of elemental zirconium, nitride, or oxynitride.

[0066] Zirconium oxide possesses excellent electrical insulation, mechanical strength, and toughness. Therefore, the inclusion of zirconium oxide in the third layer 53 enhances the properties of the diaphragm 50. Furthermore, for example, if the piezoelectric layer 70 is composed of lead zirconate titanate, the inclusion of zirconium oxide in the third layer 53 has the advantage of making it easier to obtain a piezoelectric layer 70 that is preferentially oriented to the (100) plane with a high orientation ratio when forming the piezoelectric layer 70.

[0067] The second layer 52 contains elements other than zirconium as constituent elements and is provided between the first layer 51 and the third layer 53, covering the entire surface of the pressure chamber substrate 10. Because the second layer 52 prevents contact between the first layer 51 and the third layer 53, the reduction of silicon oxide in the first layer 51 by zirconium in the third layer 53 is reduced.

[0068] Here, the second layer 52 is preferably a layer containing a metal element that is less susceptible to oxidation than zirconium, which is a constituent element of the third layer 53, and is more preferably composed of an oxide of that metal element. In other words, the second layer 52 preferably contains a metal element with a greater oxide formation free energy than zirconium. The relative magnitudes of the oxide formation free energies can be evaluated, for example, based on a known Ellingham diagram.

[0069] Specifically, the second layer 52 is preferably composed of one of the following metal elements: titanium (Ti), aluminum (Al), chromium (Cr), or tantalum (Ta). The second layer 52 may contain only one metal element, or it may contain two or more metal elements.

[0070] By including a metal element that is less susceptible to oxidation than zirconium in the second layer 52, the reduction of silicon oxide in the first layer 51 can be reduced compared to a configuration in which the second layer 52 contains a metal element that is more susceptible to oxidation than zirconium, that is, compared to a configuration in which the oxide formation free energy of the metal element in the second layer 52 is smaller than that of zirconium. As a result, the adhesion between the first layer 51 and the third layer 53 can be increased compared to a configuration in which the second layer 52 is not used.

[0071] Furthermore, by providing the second layer 52, the formation of gaps at the interface of the third layer 53 can be suppressed. In other words, it is possible to suppress the intrusion of moisture into the interface between the third layer 53 and the second layer 52. Therefore, it is possible to suppress the embrittlement of the zirconium in the third layer 53 by moisture, and to suppress damage such as delamination and cracking of the third layer 53.

[0072] Furthermore, it is preferable that the material of the second layer 52 has a Young's modulus higher than that of the material of the first layer 51. As mentioned above, it is preferable that the second layer 52 contains one of the following metallic elements as a constituent element: titanium (Ti), aluminum (Al), chromium (Cr), or tantalum (Ta). This makes it possible to suppress over-etching when etching the third layer 53, as will be described later.

[0073] Preferably, the material of the second layer 52 has a Young's modulus higher than that of the material of the third layer 53. For example, titanium (Ti) and aluminum (Al) have a Young's modulus higher than that of zirconium (Zr), which is the material of the third layer 53. Therefore, by using these materials for the second layer 52, the function as an etching stop layer can be ensured even if the thickness of the second layer 52 is relatively thin. Furthermore, by reducing the thickness of the second layer 52, the displacement of the diaphragm 50 can also be improved. In addition, by using these materials for the second layer 52, atomic diffusion can be suppressed. As a result, the generation of leakage current can be suppressed.

[0074] On the other hand, for example, chromium (Cr) and tantalum (Ta) have lower Young's moduli than zirconium (Zr), which is the material for the third layer 53. Therefore, using these materials as the material for the second layer 52 makes it easier to improve the displacement of the diaphragm 50. Furthermore, even when using these materials, increasing the thickness of the second layer 52 allows it to function as an etching stop layer.

[0075] By the way, in the recording head 2 according to the present invention, the third layer 53 constituting the diaphragm 50 is not provided on the entire surface of the diaphragm 50, but is provided in a predetermined area.

[0076] Specifically, as shown in Figure 5, the third layer 53 is provided in the region corresponding to each pressure chamber 12 in the X-axis direction, which is perpendicular to the direction in which the individual lead electrodes 91 are drawn out. In this embodiment, the third layer 53 is formed with approximately the same width as the piezoelectric layer 70. That is, both ends of the third layer 53 in the X-axis direction are located inside the pressure chamber 12 and outside the ends of the first electrode 60. Therefore, there are parts of the pressure chamber 12 facing both ends in the X-axis direction, the so-called arms of the diaphragm 50, where the third layer 53 is not formed. This makes it possible to improve the amount of displacement of the diaphragm 50 associated with the driving of the piezoelectric element 300. In this embodiment, the positions of both ends of the third layer 53 in the Y-axis direction are located outside the pressure chamber 12.

[0077] Thus, the third layer 53 is provided spaced apart in the region corresponding to each pressure chamber 12 in the X-axis direction. In other words, the diaphragm 50 has the following configuration. For example, in Figure 5, the region of the diaphragm 50 that overlaps with the pressure chamber 12 when viewed in the first direction, the Z-axis direction, and also overlaps with the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is called the active region A1. That is, the region of the diaphragm 50 facing the pressure chamber 12 that overlaps with the active part 310 of the piezoelectric element 300 is called the active region A1.

[0078] Furthermore, the region of the diaphragm 50 that overlaps with the pressure chamber 12 when viewed in the Z-axis direction, and does not overlap with the first electrode 60, the piezoelectric layer 70, and the second electrode 80, is referred to as the inactive region A2. In other words, the region of the diaphragm 50 facing the pressure chamber 12 that does not overlap with the active portion 310 of the piezoelectric element 300 is referred to as the inactive region A2. In this embodiment, the region that overlaps with the pressure chamber 12 when viewed in the Z-axis direction, and does not overlap with the first electrode 60, becomes the inactive region A2. That is, the region of the diaphragm 50 facing the pressure chamber 12 that is different from the active region A1 becomes the inactive region A2. This inactive region A2 includes the region corresponding to the so-called arm portion of the diaphragm 50, and in this embodiment, the active region A1 is located between the two inactive regions A2 in a cross-sectional view in the Z-axis direction.

[0079] In this embodiment, the pressure chamber substrate 10, diaphragm 50, first electrode 60, piezoelectric layer 70, and second electrode 80 are stacked in this order in the Z-axis direction, and the second electrode 80, which is a common electrode, is continuously provided from the active region A1 to the inactive region A2.

[0080] In the X-axis direction, the diaphragm 50 in the active region A1 has a first layer 51, a second layer 52, and a third layer 53. On the other hand, in the X-axis direction, a portion of the diaphragm 50 in the non-active region A2 has the first layer 51 and the second layer 52, but does not have the third layer 53. That is, the first layer 51 and the second layer 52 constituting the diaphragm 50 are formed continuously over the entire area between the active region A1 and the non-active region A2, but the third layer 53 is removed in a portion of the non-active region A2. In this embodiment, the third layer 53 is removed in a portion of the non-active region A2 on the partition wall 11 side. Thus, the portion of the diaphragm 50 that overlaps with the pressure chamber 12 and does not overlap with the third layer 53 when viewed in the first direction, the Z-axis direction, is called the removal region A3. Note that the removal region A3 is a part of the non-active region A2. In this removal region A3, the diaphragm 50 is composed of a first layer 51 and a second layer 52. In this embodiment, the position of the end of the third layer 53 in the X-axis direction, that is, the boundary of the removal region A3, is located on the extension of the end face of the piezoelectric layer 70 defined by the groove 71.

[0081] Furthermore, in this embodiment, in the X-axis direction, the third layer 53 is removed not only from the non-active region A2 but also from the region outside the pressure chamber 12. In other words, in the X-axis direction, even in the region outside the pressure chamber 12, the diaphragm 50 is composed of the first layer 51 and the second layer 52. However, the third layer 53 in the region outside the pressure chamber 12 does not necessarily have to be removed.

[0082] As described above, the recording head 2 according to this embodiment includes a piezoelectric element 300 comprising a first electrode 60, a piezoelectric layer 70, and a second electrode 80 stacked in the first direction, the Z-axis direction; a diaphragm 50 that vibrates when driven by the piezoelectric element 300; and a pressure chamber substrate 10 that partitions a pressure chamber 12 that applies pressure to the liquid ink by the vibration of the diaphragm 50. The pressure chamber substrate 10, the diaphragm 50, and the piezoelectric element 300 are stacked in this order in the Z-axis direction. The diaphragm 50 comprises a first layer 51 containing silicon as a constituent element, a second layer 52 disposed between the first layer 51 and the first electrode 60 and containing a metallic element other than zirconium as a constituent element, and the second layer The diaphragm 50 includes a third layer 53 disposed between 52 and the first electrode 60 and containing zirconium as a constituent element, and when the region of the diaphragm 50 that overlaps with the pressure chamber 12 and overlaps with the first electrode 60, the piezoelectric layer 70 and the second electrode 80 when viewed in the Z-axis direction is defined as the active region A1, and the region of the diaphragm 50 that overlaps with the pressure chamber 12 and does not overlap with the first electrode 60, the piezoelectric layer 70 and the second electrode 80 when viewed in the Z-axis direction is defined as the inactive region A2, the diaphragm 50 has the first layer 51, the second layer 52 and the third layer 53 in the active region A1, and the first layer 51 and the second layer 52 and the third layer 53 in at least a part of the inactive region A2.

[0083] This configuration improves the amount of displacement of the diaphragm 50 associated with the driving of the piezoelectric element 300 while suppressing the occurrence of cracks in the diaphragm 50. Furthermore, because the diaphragm 50 has a second layer 52 in the active region A1 and the inactive region A2, when the third layer 53 is removed, for example, by dry etching in a part of the inactive region A2, i.e., the arm portion of the diaphragm, the first layer 51, which contains silicon as a constituent element, will not be removed by over-etching. Therefore, a decrease in the reliability of the diaphragm 50 can be prevented.

[0084] In this case, since the third layer 53, which contains zirconium as a constituent element, is removed from at least a portion of the non-active region A2 of the diaphragm 50, specifically the removal region A3 in this embodiment, the edges of the third layer 53 remain in the non-active region A2. As a result, moisture may penetrate from the edges of the third layer 53 to the interface between the third layer 53 and its underlying layer, potentially causing damage such as delamination or cracking of the third layer 53.

[0085] However, in the present invention, the diaphragm 50 is provided with a second layer 52 containing metal elements other than zirconium as constituent elements, that is, the second layer 52 is provided as a base layer for the third layer 53, thereby improving the adhesion of the third layer 53. As a result, it is possible to suppress the intrusion of moisture from the edge of the third layer 53 located in the non-active region A2 to the interface between the third layer 53 and the second layer 52. Consequently, it is possible to suppress the embrittlement of the zirconium in the third layer 53 due to moisture, and to suppress damage such as peeling and cracking of the third layer 53.

[0086] Furthermore, in the removal region A3 where the third layer 53 of the diaphragm 50 within the non-active region A2 is removed, the thickness of the diaphragm 50 becomes thinner and stress tends to concentrate, which may cause cracks or delamination of the second electrode 80 provided in this removal region A3.

[0087] However, in the present invention, the second electrode 80 is directly laminated on the second layer 52 in the removal region A3 of the diaphragm 50, and the second electrode 80 and the second layer 52 are formed from materials with high affinity for each other. For example, when a metallic material such as titanium (Ti) or iridium (Ir) is used as the material for the second electrode 80, an oxide or nitride of these metallic materials is used as the material for the second layer 52. That is, the second electrode 80 contains a single metallic element, and the second layer 52 contains an oxide or nitride of the said metallic element.

[0088] This improves the adhesion between the second layer 52 of the diaphragm 50 and the second electrode 80 that constitutes the piezoelectric element 300, thereby suppressing damage to the diaphragm 50 and the second electrode 80 in the arm portion.

[0089] Furthermore, it is preferable that the second layer 52 is formed continuously between the active region A1 and the inactive region A2 of the diaphragm 50. In other words, it is preferable that the second layer 52 is formed over the entire area within both the active region A1 and the inactive region A2. This makes it easier to suppress the occurrence of cracks in the diaphragm 50.

[0090] The second layer 52 does not necessarily have to be formed continuously between the active region A1 and the inactive region A2 of the diaphragm 50. For example, there may be a region in the central part of the area where the third layer 53 of the diaphragm 50 is formed in which the second layer 52 is not formed.

[0091] Furthermore, it is preferable that the Young's modulus of the material of the second layer 52 is higher than that of the material of the first layer 51. This makes it easier to suppress over-etching when etching the third layer 53 of the diaphragm 50.

[0092] The second layer 52 preferably contains a metal element that is less susceptible to oxidation than zirconium, which is a constituent element of the third layer 53. The second layer 52 preferably contains one of the following metal elements as a constituent element: titanium, aluminum, chromium, or tantalum.

[0093] In the relationship between the first layer 51 and the third layer 53, the zirconium (Zr) contained in the third layer is relatively easily oxidized, while the silicon oxide (SiO2) contained in the first layer 51 is easily reduced. Therefore, when the third layer 53 and the first layer 51 are directly laminated, the silicon oxide in the first layer is reduced. The elemental silicon generated by this reduction diffuses from the first layer 51 to the third layer 53, which may cause voids to form at the interface of the third layer 53.

[0094] However, by providing a second layer 52 between the first layer 51 and the third layer 53, and by making this second layer 52 contain a metal element that is less susceptible to oxidation than zirconium, which is a constituent element of the third layer 53, the generation of voids caused by the above-mentioned diffusion can be suppressed. Therefore, the adhesion force of the third layer 53 can be improved, and damage such as peeling and cracking of the third layer 53 can be suppressed.

[0095] Furthermore, in at least a portion of the non-active region A2, it is preferable that the second layer 52 of the diaphragm 50 is laminated adjacent to one of the electrodes, either the first electrode 60 or the second electrode 80. For example, in this embodiment, in at least a portion of the non-active region A2, i.e., the removal region A3, the second layer 52 of the diaphragm 50 is laminated adjacent to the second electrode 80.

[0096] Furthermore, it is preferable that the constituent elements of the second electrode 80, which is laminated adjacent to the second layer 52 of the diaphragm 50, include the metal elements contained in the second layer 52. Moreover, it is preferable that the second electrode 80, which is laminated adjacent to the second layer 52 of the diaphragm 50, contains the elemental form of the said metal, and the second layer 52 contains an oxide or nitride of the said metal.

[0097] This improves the adhesion between the second layer 52 of the diaphragm 50 and the second electrode 80 that constitutes the piezoelectric element 300, thereby suppressing damage to the diaphragm 50 and the second electrode 80 in the arm portion.

[0098] In the non-active region A2, the removal region A3, which overlaps with the pressure chamber 12 when viewed in the first direction (Z-axis direction) and does not have the third layer 53, preferably does not overlap with the piezoelectric layer 70 when viewed in the first direction. This is because the crystallinity of the piezoelectric layer 70 tends to be more homogeneous compared to the case where the piezoelectric layer 70 is continuously formed in both the region of the diaphragm 50 where the third layer 53 is formed and the region where the third layer 53 is not formed.

[0099] In this embodiment, the end of the third layer 53 of the diaphragm 50 in the X-axis direction is located on the extension line of the end face of the piezoelectric layer 70. However, the end of the third layer 53 does not necessarily have to be located on the extension line of the end face of the piezoelectric layer 70. The end of the third layer 53 in the X-axis direction may be located outside the extension line of the end face of the piezoelectric layer 70. Alternatively, the end of the third layer 53 in the X-axis direction may be located inside the extension line of the end face of the piezoelectric layer 70.

[0100] Furthermore, in this embodiment, a configuration in which the third layer 53 is removed in a portion of the removal area A3 within the non-active area A2 is illustrated. However, the range of the removal area A3 within the non-active area A2 is not particularly limited, and for example, the non-active area A2 and the removal area A3 may coincide. In other words, the third layer 53 does not have to be formed throughout the entire non-active area A2.

[0101] (Embodiment 2) Figure 6 is a cross-sectional view of the recording head according to Embodiment 2. This embodiment is a modified version of the diaphragm 50 and piezoelectric element 300 of the recording head 2, while the other configurations are the same as in Embodiment 1. The same reference numerals are used for the same components as in Embodiment 1, and redundant explanations are omitted. Furthermore, the distinguishing feature of the recording head 2 in this embodiment lies in the configuration of the diaphragm 50, while the basic configuration of the piezoelectric element 300 is existing.

[0102] As shown in Figure 6, the recording head 2 according to this embodiment includes a piezoelectric element 300 provided on the -Z side of the diaphragm 50, where the first electrode 60 of the piezoelectric element 300 constitutes a common electrode and the second electrode 80 constitutes an individual electrode.

[0103] The diaphragm 50, like in Embodiment 1, has a first layer 51, a second layer 52, and a third layer 53, which are stacked in this order in the -Z direction. The third layer 53 is not provided across the entire surface of the diaphragm 50, but is provided in a predetermined area. That is, in the X-axis direction, the third layer 53 is formed to be narrower than the width of the pressure chamber 12.

[0104] The first electrode 60 constituting the piezoelectric element 300 according to this embodiment is continuously provided on the diaphragm 50 having a first layer 51, a second layer 52, and a third layer 53, extending over regions corresponding to multiple pressure chambers 12, and serves as a common electrode common to multiple active parts 310. That is, the first electrode 60 is continuously formed on the second layer 52 and the third layer 53 of the diaphragm 50 in the X-axis direction.

[0105] The second electrode 80 is laminated on the -Z side of the first electrode 60 via a piezoelectric layer 70, and is separated for each pressure chamber 12 to form an independent individual electrode for each active portion 310. The second electrode 80 is formed with a width narrower than the pressure chamber 12 in the X-axis direction. That is, in the X-axis direction, the end of the second electrode 80 is located inside the region facing the pressure chamber 12. In this embodiment, the end of the second electrode 80 in the X-axis direction substantially coincides with the position of the end of the piezoelectric layer 70.

[0106] Furthermore, a protective film 150 made of an insulating material is provided on the piezoelectric element 300. Although not shown in the illustration, the common lead electrode connected to the first electrode 60 and the individual lead electrodes connected to each of the second electrodes 80 are provided on this protective film 150.

[0107] In this embodiment of the recording head 2, the diaphragm 50 has the same configuration as in Embodiment 1. For example, in Figure 6, the region of the diaphragm 50 that overlaps with the pressure chamber 12 when viewed in the first direction, the Z-axis direction, and also overlaps with the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is referred to as the active region A1. That is, the region of the diaphragm 50 facing the pressure chamber 12 that overlaps with the active part 310 of the piezoelectric element 300 is referred to as the active region A1. In addition, the region of the diaphragm 50 that overlaps with the pressure chamber 12 when viewed in the Z-axis direction, and does not overlap with the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is referred to as the non-active region A2. That is, the region of the diaphragm 50 facing the pressure chamber 12 that does not overlap with the active part 310 of the piezoelectric element 300 is referred to as the non-active region A2. This inactive region A2 includes the region corresponding to the arm portion of the so-called diaphragm 50, and in this embodiment, the active region A1 is located between the two inactive regions A2 in a cross-sectional view in the Z-axis direction.

[0108] Furthermore, in the Z-axis direction, the pressure chamber substrate 10, diaphragm 50, first electrode 60, piezoelectric layer 70, and second electrode 80 are stacked in this order, and the first electrode 60, which is a common electrode, is continuously provided in the X-axis direction from the active region A1 to the inactive region A2.

[0109] The diaphragm 50 in the active region A1 in the X-axis direction has a first layer 51, a second layer 52, and a third layer 53. On the other hand, a portion of the diaphragm 50 in the non-active region A2 in the X-axis direction has a first layer 51 and a second layer 52, but does not have a third layer 53. That is, the first layer 51 and the second layer 52 that constitute the diaphragm 50 are formed continuously throughout the entire area between the active region A1 and the non-active region A2, but the third layer 53 is removed in a portion of the non-active region A2. In other words, the third layer 53 is removed in the removal region A3 on the partition wall 11 side of the non-active region A2, and the diaphragm 50 in this removal region A3 is composed of the first layer 51 and the second layer 52.

[0110] In this embodiment, the same effects and advantages as in Embodiment 1 can be obtained. For example, it is possible to improve the amount of displacement of the diaphragm 50 associated with the driving of the piezoelectric element 300 while suppressing the occurrence of cracks in the diaphragm 50. Furthermore, because the diaphragm 50 has a second layer 52 in the active region A1 and the non-active region A2, it is possible to suppress over-etching when etching the third layer 53 in the arm portion of the diaphragm 50, thereby preventing a decrease in the reliability of the diaphragm 50.

[0111] (Embodiment 3) Figure 7 is a cross-sectional view of the recording head according to Embodiment 3. This embodiment is a modified version of the diaphragm 50 and piezoelectric element 300 of the recording head 2, and the other configurations are the same as in the embodiment described above. The same reference numerals are used for the same components as in Embodiment 1, and redundant explanations are omitted. The features of the recording head 2 according to this embodiment are also in the configuration of the diaphragm 50, and the basic configuration of the piezoelectric element 300 is the same as existing ones.

[0112] As shown in Figure 7, the piezoelectric element 300 is provided on the -Z side of the pressure chamber substrate 10 via a diaphragm 50 having a first layer 51, a second layer 52, and a third layer 53, and comprises a first electrode 60, a piezoelectric layer 70, and a second electrode 80 stacked in the Z-axis direction.

[0113] The active portion 310 of the piezoelectric element 300, although not shown in the figure, is provided in an annular shape along the opening edge of each pressure chamber 12 in a plan view in the Z-axis direction, and is not provided in the central part of the pressure chamber 12.

[0114] Therefore, in the cross-section in the X-axis direction shown in Figure 7, the active portion 310 of the piezoelectric element 300 is provided corresponding to both ends of the pressure chamber 12, and not in the central part of the pressure chamber 12. The active portion 310 of the piezoelectric element 300 has a similar configuration in the cross-section in the Y-axis direction. In other words, the active portion 310 extends from the inside to the outside of the pressure chamber 12 at any position on the opening edge of the pressure chamber 12.

[0115] The first electrode 60 constituting such a piezoelectric element 300 is a common electrode common to multiple active parts 310 and is continuously provided on the -Z direction side of the diaphragm 50 over a region corresponding to multiple pressure chambers 12. The piezoelectric layer 70 is provided independently for each pressure chamber 12, i.e., for each active part 310. The piezoelectric layer 70 is provided in an annular shape with a predetermined width along the opening edge of the pressure chamber 12 and is not provided in the portion corresponding to the central part of the pressure chamber 12. In this embodiment, the piezoelectric layer 70 is separated and provided independently for each active part 310, but it may also be provided continuously over multiple active parts 310.

[0116] The second electrode 80 is provided on the side of the piezoelectric layer 70 opposite to the first electrode 60, and constitutes an independent individual electrode for each active portion 310. In this embodiment, the second electrode 80 is provided continuously across the piezoelectric layer 70 that constitutes each active portion 310. That is, the second electrode 80 is provided in an annular shape along the opening edge of the pressure chamber 12 with the same width as the piezoelectric layer 70, and is not provided in the portion corresponding to the central part of the pressure chamber 12. The portion where this second electrode 80 is provided becomes the active portion 310 of the piezoelectric element 300.

[0117] Furthermore, a protective film 150 made of an insulating material is provided on the piezoelectric element 300. Although not shown in the diagram, a common lead electrode connected to the first electrode 60 and individual lead electrodes connected to each electrode 80 are provided on this protective film 150.

[0118] In this embodiment, the recording head 2 also has a third layer 53 that makes up the diaphragm 50, which is not provided over the entire surface of the diaphragm 50, but is provided in a predetermined area.

[0119] Specifically, the third layer 53 constituting the diaphragm 50 is provided in a region facing each pressure chamber 12, corresponding to the active portion 310. That is, the third layer 53 is provided in a position facing the peripheral edge of the pressure chamber 12 within the region facing the pressure chamber 12, but not in a position facing the central part of the pressure chamber 12.

[0120] Therefore, in the cross-section in the X-axis direction, which is the direction in which the pressure chambers 12 are arranged side by side as shown in Figure 7, the third layer 53 is provided at positions corresponding to both ends of the pressure chambers 12, and not in the center of the pressure chambers 12. The position of the end of the third layer 53 in the region facing the pressure chambers 12 is located on the extension line of the end face of the piezoelectric layer 70. However, the position of the end of the third layer 53 does not necessarily have to be on the extension line of the end face of the piezoelectric layer 70; it may be inside or outside the extension line of the end face of the piezoelectric layer 70 as long as it is within the non-active region A2. The diaphragm 50 including the third layer 53 has a similar configuration in the cross-section in the Y-axis direction.

[0121] In the configuration of this embodiment, the portion of the diaphragm 50 corresponding to the central part of the pressure chamber 12 corresponds to the so-called arm portion. In other words, even in the configuration of this embodiment, there is a portion of the so-called arm portion of the diaphragm 50 where the third layer 53 is not formed. This makes it possible to improve the amount of displacement of the diaphragm 50 associated with the driving of the piezoelectric element 300.

[0122] The third layer 53 is formed continuously in the region outside the pressure chamber 12. Of course, the third layer 53 does not need to be continuous in the region outside the pressure chamber 12. For example, the third layer 53 in the region outside the pressure chamber 12 where the piezoelectric layer 70 is not formed may be removed.

[0123] In this embodiment as well, the diaphragm 50 including the third layer 53 has the following configuration. For example, in Figure 7, the region of the diaphragm 50 that overlaps with the pressure chamber 12 when viewed in the first direction, the Z-axis direction, and also overlaps with the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is referred to as the active region A1. That is, the region of the diaphragm 50 facing the pressure chamber 12 that overlaps with the active part 310 of the piezoelectric element 300 is referred to as the active region A1. Furthermore, the region of the diaphragm 50 that overlaps with the pressure chamber 12 when viewed in the Z-axis direction, and does not overlap with the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is referred to as the inactive region A2. That is, the region of the diaphragm 50 facing the pressure chamber 12 that does not overlap with the active part 310 of the piezoelectric element 300 is referred to as the inactive region A2. In other words, in this embodiment, of the diaphragm 50 facing the pressure chamber 12, the region facing the central part of the pressure chamber 12 becomes the non-active region A2, and in a cross-sectional view in the Z-axis direction, the non-active region A2 is located between the two active regions A1.

[0124] In this embodiment, the pressure chamber substrate 10, diaphragm 50, first electrode 60, piezoelectric layer 70, and second electrode 80 are stacked in this order in the Z-axis direction, and the first electrode 60, which is a common electrode, is continuously provided from the active region A1 to the inactive region A2.

[0125] The diaphragm 50 in the active region A1 has a first layer 51, a second layer 52, and a third layer 53. On the other hand, the diaphragm 50 in the non-active region A2 has a first layer 51 and a second layer 52, but does not have a third layer 53. That is, the first layer 51 and the second layer 52 that constitute the diaphragm 50 are formed continuously over the entire area between the active region A1 and the non-active region A2, but the third layer 53 is removed in at least a part of the non-active region A2. In other words, the third layer 53 is removed in the removal region A3, which is the central part of the non-active region A2 excluding the outer periphery, and the diaphragm 50 in the removal region A3 is composed of the first layer 51 and the second layer 52.

[0126] In this embodiment, the same effects and advantages as in the above-described embodiment can be obtained. For example, it is possible to improve the amount of displacement of the diaphragm 50 associated with the driving of the piezoelectric element 300 while suppressing the occurrence of cracks in the diaphragm 50. Furthermore, by having the diaphragm 50 have a second layer 52 in the active region A1 and the non-active region A2, when etching the third layer 53 in the part corresponding to the central part of the pressure chamber 12 of the diaphragm 50, that is, in the arm portion of the diaphragm 50, over-etching can be suppressed, and a decrease in the reliability of the diaphragm 50 can be prevented.

[0127] (Other embodiments) Although various embodiments of the present invention have been described above, the basic configuration of the present invention is not limited to those described above.

[0128] For example, in the above-described embodiment, the diaphragm 50 is exemplified as comprising a first layer 51, a second layer 52, and a third layer 53, but the configuration of the diaphragm 50 is not limited thereto. The diaphragm 50 may be composed of layers other than the first layer 51, the second layer 52, and the third layer 53. For example, the diaphragm 50 may have a fourth layer as a stress control layer between the first layer 51 and the second layer 52.

[0129] Furthermore, although the present invention was described using the above-described embodiment as an example of the configuration of the diaphragm 50 in the short direction of the pressure chamber 12, the present invention can of course also be applied to the configuration of the diaphragm 50 in the longitudinal direction of the pressure chamber 12.

[0130] Furthermore, in the above-described embodiment, the recording device 1 was exemplified as having a recording head 2 mounted on a transport body 8 that reciprocates along the Y-axis, which is the main scanning direction. However, the configuration of the recording device 1 is not limited to this. The present invention can also be applied to so-called line-type recording devices, for example, in which the recording head 2 is fixed and printing is performed simply by moving a medium S such as paper along the X-axis, which is the sub-scanning direction.

[0131] In the above embodiments, an inkjet recording head was given as an example of a liquid ejection head, and an inkjet recording device was given as an example of a liquid ejection device to explain the present invention. However, the present invention broadly applies to liquid ejection heads and liquid ejection devices in general. The present invention can of course also be applied to liquid ejection heads and liquid ejection devices that eject liquids other than ink. Examples of other liquid ejection heads include various recording heads used in image recording devices such as printers, colorant ejection heads used in the manufacture of color filters for liquid crystal displays, electrode material ejection heads used in electrode formation for organic EL displays and FEDs (field emission displays), and bio-organic material ejection heads used in biochip manufacturing. The present invention can also be applied to liquid ejection devices equipped with such liquid ejection heads.

[0132] Furthermore, the present invention is not limited to liquid ejection heads, such as those found in inkjet recording heads, but can also be applied to piezoelectric devices such as ultrasonic devices, motors, pressure sensors, pyroelectric elements, and ferroelectric elements. The present invention can also be applied to complete systems utilizing these piezoelectric devices, such as liquid ejection devices using the above-mentioned liquid ejection heads, ultrasonic sensors using the above-mentioned ultrasonic devices, robots using the above-mentioned motors as a driving source, IR sensors using the above-mentioned pyroelectric elements, and ferroelectric memories using ferroelectric elements. [Explanation of Symbols]

[0133] 1... Inkjet recording device (recording device), 2... Recording head, 3... Liquid container, 4... Control unit, 5... Transport mechanism, 6... Moving mechanism, 7... Transport roller, 8... Transport body, 9... Transport belt, 10... Pressure chamber substrate, 11... Partition wall, 12... Pressure chamber, 15... Connecting plate, 16... Nozzle connecting passage, 17... First manifold section, 18... Second manifold section, 19... Supply connecting passage, 20... Nozzle plate, 21... Nozzle, 30... Protective substrate, 31... Holding section, 32... Through hole, 40... Case member, 41... Housing section, 42... Third manifold section 43...Connection port, 44...Inlet, 45...Compliance substrate, 46...Sealing film, 47...Fixed substrate, 48...Opening, 49...Compliance section, 50...Diaphragm, 51...First layer, 52...Second layer, 53...Third layer, 60...First electrode, 70...Piezoelectric layer, 71...Groove section, 80...Second electrode, 91...Individual lead electrodes, 92...Common lead electrodes, 100...Manifold, 120...Wiring board, 121...Drive circuit, 150...Protective film, 300...Piezoelectric element, 310...Active section, S...Medium, A1...Active region, A2...Inactive region, A3...Removal region

Claims

1. A piezoelectric element comprising a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction, A diaphragm that vibrates by driving the piezoelectric element, A pressure chamber substrate that partitions a pressure chamber in which pressure is applied to a liquid by the vibration of the aforementioned diaphragm, It has, The pressure chamber substrate, the diaphragm, and the piezoelectric element are stacked in this order in the first direction. The aforementioned diaphragm is The first layer contains silicon as a constituent element, A second layer is disposed between the first layer and the piezoelectric layer and contains metal elements other than zirconium as constituent elements, The material includes a third layer disposed between the second layer and the piezoelectric layer, and containing zirconium as a constituent element, Of the diaphragm, the region that overlaps with the pressure chamber when viewed in the first direction and overlaps with all of the first electrode, the piezoelectric layer, and the second electrode is defined as the active region. Of the diaphragm, when viewed in the first direction, the region that overlaps with the pressure chamber and does not overlap with at least one of the first electrode, the piezoelectric layer, and the second electrode is defined as the inactive region, The aforementioned diaphragm is The active region comprises the first layer, the second layer, and the third layer, In at least a portion of the non-active region, the first layer and the second layer are present, but the third layer is absent. In at least a portion of the non-active region that does not have the third layer, the second layer of the diaphragm is laminated adjacent to the second electrode. The second electrode contains the metal element included in the second layer, The second layer contains an oxide of the metal element, A liquid spray head characterized by the following features.

2. A piezoelectric element comprising a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction, A diaphragm that vibrates by driving the piezoelectric element, A pressure chamber substrate that partitions a pressure chamber in which pressure is applied to a liquid by the vibration of the aforementioned diaphragm, It has, The pressure chamber substrate, the diaphragm, and the piezoelectric element are stacked in this order in the first direction. The aforementioned diaphragm is The first layer contains silicon as a constituent element, A second layer is disposed between the first layer and the piezoelectric layer and contains metal elements other than zirconium as constituent elements, The material includes a third layer disposed between the second layer and the piezoelectric layer, and containing zirconium as a constituent element, Of the diaphragm, the region that overlaps with the pressure chamber when viewed in the first direction and overlaps with all of the first electrode, the piezoelectric layer, and the second electrode is defined as the active region. Of the diaphragm, when viewed in the first direction, the region that overlaps with the pressure chamber and does not overlap with at least one of the first electrode, the piezoelectric layer, and the second electrode is defined as the inactive region, The aforementioned diaphragm is The active region comprises the first layer, the second layer, and the third layer, In at least a portion of the non-active region, the first layer and the second layer are present, but the third layer is absent. In at least a portion of the non-active region that does not have the third layer, the second layer of the diaphragm is laminated adjacent to the second electrode. The second electrode contains the metal element included in the second layer, The second layer comprises a nitride of the metal element, A liquid spray head characterized by the following features.

3. The second layer is formed continuously between the active region and the inactive region. The liquid spray head according to feature 1.

4. The Young's modulus of the second layer material is higher than that of the first layer material. The liquid spray head according to feature 1.

5. The second layer contains one of the following metallic elements as a constituent element: titanium, aluminum, chromium, or tantalum. A liquid spray head according to any one of claims 1 to 4.

6. The second layer contains a metallic element that is less susceptible to oxidation than zirconium as a constituent element. A liquid spray head according to any one of claims 1 to 4.

7. The second electrode contains the elemental form of the metal element, The liquid spray head according to feature 1.

8. Of the aforementioned inactive regions, the region that overlaps with the pressure chamber when viewed in the first direction and does not have the third layer is, When viewed in the first direction, the piezoelectric layer does not overlap with the piezoelectric layer. A liquid spray head according to any one of claims 1 to 3.

9. In the cross-sectional view in the first direction and the short-side direction of the pressure chamber, the active region is located between the two inactive regions. A liquid spray head according to any one of claims 1 to 3.

10. In the first direction, the pressure chamber substrate, the diaphragm, the first electrode, the piezoelectric layer, and the second electrode are stacked in this order. The second electrode is provided continuously from the active region to the non-active region. The liquid spray head according to feature 9.

11. In the first direction, the pressure chamber substrate, the diaphragm, the first electrode, the piezoelectric layer, and the second electrode are stacked in this order. The first electrode is provided continuously from the active region to the non-active region. The liquid spray head according to feature 9.

12. In the cross-sectional view in the first direction and the short-side direction of the pressure chamber, the non-active region is located between the two active regions. A liquid spray head according to any one of claims 1 to 3.

13. A liquid spray head as described in claim 1 or 2. A liquid injection device characterized by the following features.

14. A substrate having a recess, A piezoelectric element comprising a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction, It has a diaphragm that vibrates when driven by the piezoelectric element, The substrate, the diaphragm, and the piezoelectric element are stacked in this order in the first direction. The aforementioned diaphragm is The first layer contains silicon as a constituent element, A second layer is disposed between the first layer and the piezoelectric layer and contains metal elements other than zirconium as constituent elements, The material includes a third layer disposed between the second layer and the piezoelectric layer, and containing zirconium as a constituent element, Of the diaphragm, the region that overlaps with the recess when viewed in the first direction and overlaps with all of the first electrode, the piezoelectric layer, and the second electrode is defined as the active region. When the region of the diaphragm that overlaps with the recess when viewed in the first direction and does not overlap with at least one of the first electrode, the piezoelectric layer, and the second electrode is defined as an inactive region, The aforementioned diaphragm is The active region comprises the first layer, the second layer, and the third layer, In at least a portion of the non-active region, the first layer and the second layer are present, but the third layer is absent. In at least a portion of the non-active region that does not have the third layer, the second layer of the diaphragm is laminated adjacent to the second electrode. The second electrode contains the metal element included in the second layer, The second layer contains an oxide of the metal element, A piezoelectric device characterized by the following features.

15. A substrate having a recess, A piezoelectric element comprising a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction, It has a diaphragm that vibrates when driven by the piezoelectric element, The substrate, the diaphragm, and the piezoelectric element are stacked in this order in the first direction. The aforementioned diaphragm is The first layer contains silicon as a constituent element, A second layer is disposed between the first layer and the piezoelectric layer and contains metal elements other than zirconium as constituent elements, The material includes a third layer disposed between the second layer and the piezoelectric layer, and containing zirconium as a constituent element, Of the diaphragm, the region that overlaps with the recess when viewed in the first direction and overlaps with all of the first electrode, the piezoelectric layer, and the second electrode is defined as the active region. When the region of the diaphragm that overlaps with the recess when viewed in the first direction and does not overlap with at least one of the first electrode, the piezoelectric layer, and the second electrode is defined as an inactive region, The aforementioned diaphragm is The active region comprises the first layer, the second layer, and the third layer, In at least a portion of the non-active region, the first layer and the second layer are present, but the third layer is absent. In at least a portion of the non-active region that does not have the third layer, the second layer of the diaphragm is laminated adjacent to the second electrode. The second electrode contains the metal element included in the second layer, The second layer comprises a nitride of the metal element, A piezoelectric device characterized by the following features.

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