Liquid discharge head and liquid discharge device

Abstract

Reduces damage such as cracks. [Solution] The liquid discharge head comprises a pressure chamber substrate having a plurality of pressure chambers arranged in a first direction, a diaphragm disposed on the pressure chamber substrate, a first electrode disposed on the diaphragm, a piezoelectric layer disposed on the first electrode, a second electrode disposed on the piezoelectric layer, and a seed layer located between the piezoelectric layer and the diaphragm for controlling the orientation of the piezoelectric layer, wherein the piezoelectric layer has a first region that does not overlap with the first electrode in the first direction and a second region that overlaps with the first electrode in the first direction, and the thickness of the portion of the seed layer corresponding to the second region is greater than the thickness of the portion of the seed layer corresponding to the first region.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head and a liquid ejection device.

Background Art

[0002] In a liquid ejection head in which a diaphragm, a first electrode, a piezoelectric layer, and a second electrode are laminated in this order on a pressure chamber substrate having a plurality of pressure chambers, a seed layer for controlling the orientation of the piezoelectric layer may be provided between the piezoelectric layer and the diaphragm. For example, Patent Document 1 describes that a single-layer seed layer is uniformly formed on a patterned first electrode, and then a piezoelectric layer is formed on the seed layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration of Patent Document 1, not only the active part which is the part of the piezoelectric layer overlapping with the first electrode, but also the non-active part which is the part of the piezoelectric layer not overlapping with the first electrode is provided with a seed layer. Therefore, although the orientation of the non-active part can be improved compared with the mode in which the seed layer is not provided in the non-active part, there is room for improvement in reducing cracks.

Means for Solving the Problems

[0005] To solve the above problems, a liquid discharge head according to a preferred embodiment of the present disclosure comprises: a pressure chamber substrate having a plurality of pressure chambers arranged in a first direction; a diaphragm disposed on the pressure chamber substrate; a first electrode disposed on the diaphragm; a piezoelectric layer disposed on the first electrode; a second electrode disposed on the piezoelectric layer; and a seed layer located between the piezoelectric layer and the diaphragm for controlling the orientation of the piezoelectric layer, wherein the piezoelectric layer has a first region that does not overlap with the first electrode in the first direction and a second region that overlaps with the first electrode in the first direction, and the thickness of the portion of the seed layer corresponding to the second region is greater than the thickness of the portion of the seed layer corresponding to the first region.

[0006] A liquid dispensing device according to a preferred embodiment of the present disclosure comprises a liquid dispensing head as described above and a control unit that controls the dispensing operation from the liquid dispensing head. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing an example of the configuration of a liquid dispensing device according to the first embodiment. [Figure 2] This is an exploded perspective view of the liquid dispensing head according to the first embodiment. [Figure 3] This is a cross-sectional view along line AA in Figure 2. [Figure 4] Figure 2 is a plan view of a portion of the liquid discharge head. [Figure 5] This is a cross-sectional view along line BB in Figure 4. [Figure 6] This is an enlarged view of part α in Figure 5. [Figure 7] This figure shows the orientation of the second region of the piezoelectric layer. [Figure 8] This figure shows the orientation of the first region of the piezoelectric layer. [Figure 9] This is an explanatory diagram of a method for manufacturing a liquid dispensing head according to the first embodiment. [Figure 10] This is an explanatory diagram of a method for manufacturing a liquid dispensing head according to the first embodiment. [Figure 11]This is a cross-sectional view of the liquid discharge head according to the second embodiment. [Figure 12] This is an explanatory diagram of a method for manufacturing a liquid dispensing head according to the second embodiment. [Figure 13] This is an explanatory diagram of a method for manufacturing a liquid dispensing head according to the second embodiment. [Modes for carrying out the invention]

[0008] Preferred embodiments of the present disclosure will be described below with reference to the attached drawings. Note that the dimensions and scale of parts in the drawings may differ from actual dimensions as appropriate, and some parts are shown schematically for ease of understanding. Furthermore, the scope of the present disclosure is not limited to these embodiments unless otherwise stated in the following description.

[0009] For convenience, the following explanation will use the X, Y, and Z axes intersecting each other as appropriate. In the following, one direction along the X axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. Similarly, opposite directions along the Y axis are the Y1 and Y2 directions. The Y1 or Y2 direction is an example of a "first direction". Also, opposite directions along the Z axis are the Z1 and Z2 directions. The Z1 direction is an example of a "second direction". In the following, viewing in the Z1 or Z2 direction may be referred to as a "planar view".

[0010] Here, typically, the Z-axis is the vertical axis, and the Z2 direction corresponds to the downward direction in the vertical. However, the Z-axis does not have to be the vertical axis. Also, the X, Y, and Z axes are typically orthogonal to each other, but are not limited to this; for example, they can intersect at an angle within the range of 80° to 100°.

[0011] 1: First Embodiment 1-1: Overall configuration of the liquid dispensing device FIG. 1 is a schematic diagram showing a configuration example of an inkjet liquid ejection device 100 according to a first embodiment. The liquid ejection device 100 is an inkjet printing device that ejects ink, which is an example of "liquid", as droplets toward a recording medium M. The recording medium M is, for example, printing paper. Note that the recording medium M is not limited to printing paper, and may be a printing target made of any material such as a resin film or fabric.

[0012] As shown in FIG. 1, the liquid ejection device 100 includes a liquid container 10, a control module 20, a conveyance mechanism 30, a movement mechanism 40, and a plurality of liquid ejection heads 50. The control module 20 is an example of a "control unit".

[0013] The liquid container 10 stores ink. Specific examples of the liquid container 10 include a cartridge that is detachable from the liquid ejection device 100, a bag-shaped ink pack composed of a flexible film, and an ink tank that can be refilled with ink. The type of ink stored in the liquid container 10 is arbitrary.

[0014] The control module 20 controls the operations of each element of the liquid ejection device 100. The control module 20 includes, for example, a processing circuit such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and a storage circuit such as a semiconductor memory. Here, the control module 20 outputs a drive signal Com for driving the liquid ejection head 50 and a control signal SI for controlling the driving of the liquid ejection head 50. With such a drive signal Com and control signal SI, the control module 20 controls the ejection operation from the liquid ejection head 50.

[0015] The conveyance mechanism 30 conveys the recording medium M along the Y-axis under the control of the control module 20.

[0016] The moving mechanism 40 reciprocates the liquid discharge head 50 along the X-axis under the control of the control module 20. The moving mechanism 40 includes a roughly box-shaped transporter 41 called a carriage that houses the liquid discharge head 50, and an endless transport belt 42 to which the transporter 41 is fixed. In addition to the liquid discharge head 50, the transporter 41 may also be equipped with the aforementioned liquid container 10.

[0017] Each of the multiple liquid ejection heads 50, under the control of the control module 20, ejects ink supplied from the liquid container 10 from each of the multiple nozzles N onto the recording medium M. This ejection occurs in parallel with the transport of the recording medium M by the transport mechanism 30 and the reciprocating movement of the liquid ejection heads 50 by the moving mechanism 40, thereby forming an image on the surface of the recording medium M using ink.

[0018] In the example shown in Figure 1, there are four liquid dispensing heads 50. However, the number of liquid dispensing heads 50 is not limited to the example in Figure 1; it can be single, three or fewer, or five or more. Furthermore, the arrangement of the multiple liquid dispensing heads 50 is not limited to the example in Figure 1; it can be any arrangement.

[0019] 1-2: Liquid dispensing head Figure 2 is an exploded perspective view of the liquid dispensing head 50 according to the first embodiment. Figure 3 is a cross-sectional view taken along line AA in Figure 2. An example of the configuration of the liquid dispensing head 50 will be described below.

[0020] As shown in Figures 2 and 3, the liquid discharge head 50 has a plurality of nozzles N arranged in the direction along the Y axis.

[0021] The multiple nozzles N of the liquid discharge head 50 are divided into a first nozzle row Ln1 and a second nozzle row Ln2, which are spaced apart from each other in the direction along the X axis. Each of the first nozzle row Ln1 and the second nozzle row Ln2 is a collection of multiple nozzles N arranged linearly in the direction along the Y axis.

[0022] The liquid discharge head 50 has a configuration that is substantially symmetrical with respect to the X-axis. However, the positions of the multiple nozzles N of the first nozzle row Ln1 and the multiple nozzles N of the second nozzle row Ln2 along the Y-axis may coincide or differ. Figures 2 and 3 illustrate a configuration in which the positions of the multiple nozzles N of the first nozzle row Ln1 and the multiple nozzles N of the second nozzle row Ln2 along the Y-axis coincide.

[0023] As shown in Figures 2 and 3, the liquid discharge head 50 includes a communication substrate 510, a pressure chamber substrate 520, a nozzle plate 530, a vibration absorber 540, a diaphragm 550, a plurality of piezoelectric elements 560, a protective substrate 570, a case 580, and a wiring substrate 590.

[0024] The communication substrate 510 and the pressure chamber substrate 520 are stacked in this order in the Z1 direction, forming a flow path for supplying ink to multiple nozzles N. A diaphragm 550, multiple piezoelectric elements 560, a protective substrate 570, a case 580, a wiring board 590, and a drive circuit 600 are installed in the region located in the Z1 direction from the stack consisting of the communication substrate 510 and the pressure chamber substrate 520. On the other hand, a nozzle plate 530 and a vibration absorber 540 are installed in the region located in the Z2 direction from the said stack. Each element of the liquid discharge head 50 is generally a plate-shaped member that is elongated in the Y direction, and is joined to each other, for example, by adhesive. The elements of the liquid discharge head 50 will be described in order below.

[0025] The nozzle plate 530 is a plate-shaped member provided with a plurality of nozzles N in the first nozzle row Ln1 and the second nozzle row Ln2, respectively. Each of the plurality of nozzles N is a through hole through which ink passes. Here, the surface of the nozzle plate 530 facing the Z2 direction is the nozzle surface FN. The nozzle plate 530 is manufactured by processing a silicon single crystal substrate using semiconductor manufacturing technology, such as dry etching or wet etching. However, other known methods and materials may be used in the manufacture of the nozzle plate 530 as appropriate. In addition, the cross-sectional shape of the nozzles N is typically circular, but is not limited to this, and may be non-circular, such as polygonal or elliptical.

[0026] The communication substrate 510 is provided with a flow path R1, a plurality of supply flow paths Ra, and a plurality of communication flow paths Na for each of the first nozzle row Ln1 and the second nozzle row Ln2. Flow path R1 is a flow path provided in common to the plurality of nozzles N, and is a flow path that communicates with the plurality of nozzles N and is upstream of the nozzles N, and is composed of an elongated hole that extends in the direction along the Y axis in a plan view taken in the direction along the Z axis. Each of the supply flow path Ra and communication flow path Na is a flow path composed of a through hole formed for each nozzle N. Each supply flow path Ra communicates with flow path R1.

[0027] The connecting substrate 510 is manufactured, similar to the nozzle plate 530 described above, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology. However, other known methods and materials may be used in the manufacture of the connecting substrate 510 as appropriate.

[0028] The pressure chamber substrate 520 is a plate-shaped member provided with a plurality of pressure chambers C1, called cavities, for each of the first nozzle row Ln1 and the second nozzle row Ln2. The plurality of pressure chambers C1 are arranged in the direction along the Y axis. Each pressure chamber C1 is formed for each nozzle N and is a long space extending in the direction along the X axis in a plan view. As described above, the pressure chamber substrate 520 has a plurality of pressure chambers C1 arranged in the Y1 direction or the Y2 direction.

[0029] The pressure chamber substrate 520 is manufactured, similar to the nozzle plate 530 described above, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology. However, other known methods and materials may be used in the manufacture of the pressure chamber substrate 520 as appropriate.

[0030] The pressure chamber C1 is located between the communication substrate 510 and the diaphragm 550. For each of the first nozzle row Ln1 and the second nozzle row Ln2, multiple pressure chambers C1 are arranged in a direction along the Y axis. The pressure chamber C1 also communicates with the communication channel Na and the supply channel Ra, respectively. Therefore, the pressure chamber C1 communicates with the nozzle N via the communication channel Na and with the channel R1 via the supply channel Ra.

[0031] The diaphragm 550 is positioned on the surface of the pressure chamber substrate 520 facing the Z1 direction. The diaphragm 550 is an elastically vibrable plate-shaped member and vibrates due to the piezoelectric element 560. Details of the diaphragm 550 will be described later with reference to Figure 5.

[0032] On the surface of the diaphragm 550 facing the Z1 direction, a plurality of piezoelectric elements 560 corresponding to the nozzles N are arranged for each of the first nozzle row Ln1 and the second nozzle row Ln2. Each piezoelectric element 560 is a passive element that deforms when a potential corresponding to the drive signal Com is supplied, causing pressure fluctuations in the ink in the pressure chamber C1. Each piezoelectric element 560 is elongated in the direction along the X axis in a plan view. The plurality of piezoelectric elements 560 are arranged in the direction along the Y axis to correspond to the plurality of pressure chambers C1. The piezoelectric elements 560 overlap the pressure chambers C1 in a plan view. The piezoelectric elements 560 apply pressure to the pressure chambers C1 which are in communication with the nozzles N that eject the ink. Details of the piezoelectric elements 560 will be explained later with reference to Figures 4 to 6.

[0033] The protective substrate 570 is a plate-shaped member installed on the surface of the diaphragm 550 facing the Z1 direction, protecting the plurality of piezoelectric elements 560 and reinforcing the mechanical strength of the diaphragm 550. Here, the plurality of piezoelectric elements 560 are housed in the space S between the protective substrate 570 and the diaphragm 550. The protective substrate 570 is made of, for example, a resin material.

[0034] Case 580 is a case for storing ink supplied to multiple pressure chambers C1. Case 580 is made of, for example, a resin material. Case 580 is provided with a flow path R2 for each of the first nozzle row Ln1 and the second nozzle row Ln2. Flow path R2 is a space connected to the aforementioned flow path R1 and is composed of an elongated hole extending in the direction along the Y axis in a plan view taken in the direction along the Z axis. Flow path R2 is in communication with the nozzles N and, together with flow path R1, functions as a reservoir R for storing ink supplied to multiple pressure chambers C1. Case 580 is provided with inlets HL for supplying ink to each reservoir R. The ink in each reservoir R is supplied to the pressure chamber C1 via each supply flow path Ra. Note that the position and number of inlets HL for each reservoir R are not limited to the examples in Figures 2 and 3 and are arbitrary.

[0035] The vibration absorber 540, also called the compliance substrate, is a flexible resin film that forms the wall surface of the reservoir R and absorbs pressure fluctuations of the ink in the reservoir R. The vibration absorber 540 may also be a flexible thin plate made of metal. The surface of the vibration absorber 540 facing the Z1 direction is joined to the communication substrate 510 by adhesive or the like.

[0036] The wiring board 590 is mounted on the surface of the diaphragm 550 facing the Z1 direction and is a mounting component for electrically connecting the control module 20 and the liquid discharge head 50. The wiring board 590 is a flexible wiring board such as COF (Chip On Film), FPC (Flexible Printed Circuit), or FFC (Flexible Flat Cable). In this embodiment, a drive circuit 600 is mounted on the wiring board 590. Under the control of the control module 20, the drive circuit 600 switches whether or not to supply pulses included in the drive signal Com output from the control module 20 to each of the plurality of piezoelectric elements 560 of the liquid discharge head 50. As described above, the wiring board 590 supplies the drive signal Com that drives the piezoelectric elements 560. Note that the wiring board 590 may be a rigid board. In this case, the drive circuit 600 is mounted on the rigid board or on a flexible board connected to the rigid board.

[0037] 1-3: Piezoelectric element Figure 4 is a plan view of a part of the liquid discharge head 50 shown in Figure 2. Figure 5 is a cross-sectional view along line BB in Figure 4. Figure 6 is an enlarged view of part α in Figure 5. In Figure 4, for ease of viewing, the portion of the second electrode 562 not covered by the second wiring 120 described later is indicated by dots.

[0038] The configuration of the diaphragm 550 and the piezoelectric element 560 will be described below with reference to Figures 4 to 6.

[0039] The diaphragm 550 has a first layer 551 and a second layer 552, which are stacked in this order in the Z1 direction.

[0040] The first layer 551 is an elastic film composed of, for example, silicon oxide (SiO2), and is formed by thermal oxidation of one side of a silicon single crystal substrate. The second layer 552 is an insulating film composed of, for example, zirconium oxide (ZrO2), and is formed by forming a zirconium layer by sputtering and then thermally oxidizing the layer.

[0041] The diaphragm 550 is not limited to the lamination of the first layer 551 and the second layer 552 described above, but may also be composed of a single layer or three or more layers. Furthermore, the material of each layer constituting the diaphragm 550 is not limited to the materials described above, but may be silicon or silicon nitride, for example. For example, in addition to ZrO2, TiO2, Al2O3, SiO2, SiN, etc. can be used as the material constituting the second layer 552. Also, the relative thicknesses of the first layer 551 and the second layer 552 are not limited to the illustrated example and are arbitrary.

[0042] Multiple piezoelectric elements 560 are arranged on the surface of the diaphragm 550 facing the Z1 direction. As shown in Figure 5, each piezoelectric element 560 has a first electrode 561, a second electrode 562, a piezoelectric layer 563, and a seed layer 130. These are the first electrode 561, the piezoelectric layer 563, the second electrode 562, and the seed layer 130, and they are stacked in this order in the Z1 direction. Thus, the liquid discharge head 50 has the first electrode 561, the piezoelectric layer 563, the second electrode 562, and the seed layer 130.

[0043] In the piezoelectric element 560, when a voltage is applied between the first electrode 561 and the second electrode 562, the piezoelectric layer 563 deforms due to the inverse piezoelectric effect. When the diaphragm 550 vibrates in conjunction with this deformation, the pressure in the pressure chamber C1 fluctuates, causing ink to be ejected from the nozzle N. In the piezoelectric element 560, when viewed along the Z-axis, the part where the first electrode 561, the second electrode 562, and the piezoelectric layer 563 overlap is the active part, and the part other than the active part is the inactive part.

[0044] As shown in Figure 4, the first electrode 561 is electrically connected to the first wiring 110, and a drive signal Com is supplied via the first wiring 110. The first wiring 110 is a lead wire provided individually for each piezoelectric element 560 and is electrically connected to the first electrode 561 of the corresponding piezoelectric element 560. On the other hand, the second electrode 562 is electrically connected to the second wiring 120, and a constant potential is supplied via the second wiring 120. The second wiring 120 is a common wiring provided in common to multiple piezoelectric elements 560 and is electrically connected to the second electrode 562.

[0045] In the example shown in Figure 4, the first wiring 110 is connected to the first electrode 561 and is drawn out from the first electrode 561 toward the wiring board 590 for each piezoelectric element 560. On the other hand, the second wiring 120 is drawn out from both ends of the second electrode 562 in the Y1 and Y2 directions toward the wiring board 590 toward the diaphragm 550. Here, the second wiring 120 has strip-shaped conductive layers 121 and 122 extending in the Y1 direction. The conductive layers 121 and 122 are arranged at a predetermined interval in the X1 direction. Such second wiring 120 also functions as a weight to suppress vibration of the diaphragm 550.

[0046] The constituent materials of the first wiring 110 and the second wiring 120 are not particularly limited, but examples include metals such as gold (Au), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), platinum (Pt), and aluminum (Al). Among these, gold (Au) is preferably used as the constituent material for the first wiring 110 and the second wiring 120. Here, for each of the first wiring 110 and the second wiring 120, a structure in which a layer made of gold is laminated as a surface layer on top of a layer made of nickel-chromium or the like is preferably used.

[0047] The first electrode 561 is an individual electrode positioned on the diaphragm 550, spaced apart from each other for each piezoelectric element 560. A drive signal Com is supplied to the first electrode 561. The second electrode 562 is a common strip-shaped electrode positioned on the piezoelectric layer 563, extending along the Y-axis to be continuous across multiple piezoelectric elements 560. A constant potential is supplied to the second electrode 562, for example.

[0048] Examples of materials that make up the first electrode 561 and the second electrode 562 include metallic materials such as platinum (Pt), aluminum (Al), iridium (Ir), nickel (Ni), gold (Au), and copper (Cu). Of these, one type can be used alone, or two or more types can be used in combination in the form of an alloy or laminate.

[0049] In the examples shown in Figures 5 and 6, an adhesion layer 561b is placed between the diaphragm 550 and the first electrode 561. The adhesion layer 140 is a layer that enhances the adhesion between the first electrode 561 and the diaphragm 550, and is made of a metal such as titanium.

[0050] The piezoelectric layer 563 is placed on the first electrode 561 and is composed of a piezoelectric material. A composite oxide having a perovskite structure represented by the general composition formula ABO3 is preferably used as the piezoelectric material. Examples of such composite oxides include lead zirconate titanate (Pb(Zr,Ti)O3) and lead magnesium niobate / lead titanate solid solution (Pb(Mg,Nb)O3-PbTiO3). When the piezoelectric layer 563 contains Pb, Zr, and Ti, it has the advantage of easily enhancing the piezoelectric properties of the piezoelectric layer 563. Furthermore, the composite oxide is not limited to the lead-containing compounds mentioned above, but may also be a lead-free compound, such as potassium sodium niobate ((K,Na)NbO3, abbreviated as "KNN"), bismuth ironate ((BiFeO3), abbreviated as "BFO"), potassium sodium lithium niobate ((K,Na,Li)(NbO3)), potassium sodium lithium tantalate niobate ((K,Na,Li)(Nb,Ta)O3), bismuth manganate (BiMnO3, abbreviated as "BM"), etc. In this way, when the piezoelectric layer 563 contains K, Na, and Nb, the piezoelectric layer 563 can be constructed from a lead-free material.

[0051] In the example shown in Figure 4, the piezoelectric layer 563 is a strip-shaped structure extending along the Y-axis so as to be continuous across multiple piezoelectric elements 560. Here, the piezoelectric layer 563 is provided with notches G extending along the X-axis, penetrating the piezoelectric layer 563 in regions corresponding to the gaps between adjacent pressure chambers C1 in a plan view. Note that the piezoelectric layer 563 may be provided individually for each piezoelectric element 560. The notches G may also be closed-end grooves.

[0052] As shown in Figure 6, the piezoelectric layer 563 has a first region A1, a second region A2, and a third region A3. The first region A1 is a region of the piezoelectric layer 563 that does not overlap with the first electrode 561 in the Y1 or Y2 direction. In other words, the first region A1 is a region in the piezoelectric layer 563 whose range along the Y axis is different from that of the first electrode 561. On the other hand, the second region A2 is a region of the piezoelectric layer 563 that overlaps with the first electrode 561 in the Y1 or Y2 direction. In other words, the second region A2 is a region in the piezoelectric layer 563 whose range along the Y axis is the same as that of the first electrode 561. The third region A3 is a region of the piezoelectric layer 563 that is located between the first region A1 and the second region A2 in the Y1 or Y2 direction.

[0053] In the example shown in Figure 6, the first region A1 is stacked on a region F1 on the upper surface of the diaphragm 550 that is flat along the Y1 or Y2 direction when viewed in a cross section perpendicular to the X-axis. Region F1 can also be described as a flat region on the upper surface of the diaphragm 550 that is aligned with a virtual plane perpendicular to the Z-axis. On the other hand, the second region A2 is stacked on a region F2 on the upper surface of the first electrode 561 that is flat along the Y1 or Y2 direction when viewed in a cross section perpendicular to the X-axis. Region F2 can also be described as a flat region on the upper surface of the first electrode 561 that is aligned with a virtual plane perpendicular to the Z-axis. The third region A3 is stacked on a region F3 on the upper surface of the first electrode 561 that is inclined with respect to the Y1 or Y2 direction when viewed in a cross section perpendicular to the X-axis. Region F3 can also be described as a flat region on the upper surface of the first electrode 561 that is inclined around the X-axis with respect to a virtual plane perpendicular to the Z-axis.

[0054] The inclination angle of region F3 with respect to a virtual plane perpendicular to the Z-axis is not particularly limited and can be arbitrary, as long as it is greater than 0° and less than 90°. Furthermore, the inclination of region F3 with respect to the virtual plane perpendicular to the Z-axis can be formed, for example, by adjusting the etching rate when patterning the first electrode 561 by etching, or by using a grayscale mask.

[0055] The seed layer 130 is located between the piezoelectric layer 563 and the diaphragm 550, and is a layer for controlling the orientation of the piezoelectric layer 563. The seed layer 130 is in contact with each of the first electrode 561, the diaphragm 550, and the piezoelectric layer 563, and has a crystal structure that serves as a seed crystal for the piezoelectric layer 563. Thereby, the orientation of the piezoelectric layer 563 can be improved. As a result, the displacement force of the piezoelectric element 560 can be increased. Therefore, the discharge performance of the liquid discharge head 50 can be enhanced.

[0056] The material constituting the seed layer 130 may be any material as long as it has a function of controlling the orientation of the piezoelectric layer 563, but it preferably contains titanium (Ti), and more preferably contains bismuth (Bi), iron (Fe), titanium (Ti), and lead (Pb). A material containing bismuth (Bi), iron (Fe), titanium (Ti), and lead (Pb) can control the orientation of the piezoelectric layer 563 as a complex oxide having a perovskite structure containing Bi and Pb at the A site and Fe and Ti at the B site. More specifically, the seed layer 130 is preferably made of a complex oxide represented by X Bi (a-x) Fe y Ti (b-y) O z However, a > x and b > y. Here, it is preferable that 0.04 < x / (a - x) < 1.40 is satisfied.

[0057] In the present embodiment, the seed layer 130 is composed of a single layer disposed over both the first region A1 and the second region A2. By disposing the seed layer 130 over both the first region A1 and the second region A2 in this manner, the orientation of the piezoelectric layer 563 can be controlled in both the active portion and the non-active portion. Further, since the seed layer 130 is composed of a single layer, the number of interfaces that can cause damage such as peeling can be reduced.

[0058] The thickness t2 of the seed layer 130 corresponding to the second region A2 is greater than the thickness t1 of the seed layer 130 corresponding to the first region A1. This allows for a favorable increase in the crystallinity of both the first region A1 and the second region A2 of the piezoelectric layer 563. As a result, the occurrence of cracks in the piezoelectric layer 563 is favorably reduced. It should be noted that the seed layer 130 can be said to correspond to the second seed layer 132 of the second embodiment described later.

[0059] In the active part, the properties of the piezoelectric material directly affect the discharge characteristics, so it is particularly necessary to enhance the orientation to a specific plane orientation (e.g., (100) orientation). To enhance the orientation, it is preferable to increase the thickness of the seed layer 130, which is made of BFTP (Bi, Fe, Ti, Pb), etc.

[0060] On the other hand, in the non-active portion, although a piezoelectric material is formed on its upper surface, the first electrode 561 is not provided in that region, so the piezoelectric material is not driven. Therefore, if we consider the discharge characteristics, there is no need to provide a seed layer 130 in the non-active portion and control the orientation of the piezoelectric material on its upper surface. However, if the active portion is oriented to a specific plane orientation and the non-active portion is unoriented, cracks may occur between the active and non-active portions. This is because even with the same piezoelectric material, the Young's modulus and thermal expansion coefficient differ depending on the orientation, and stress caused by this difference occurs between the active and non-active portions.

[0061] However, if a seed layer 130 is also provided in the non-active section, and its thickness is the same as or greater than that of the active section, problems arise such as a decrease in discharge characteristics or a failure to improve crack formation.

[0062] Regarding the former, since the non-active part is located at the end of the pressure chamber C1, expansion and contraction are required to be more pronounced than in the active part. If the seed layer 130 is made thick in such a region, the expansion and contraction will be inhibited by its thickness, and as a result the displacement of the active part will decrease.

[0063] Regarding the latter, typically, the crystallinity of the piezoelectric layer 563 improves as the thickness of the seed layer 130 increases. However, for example, if KNN is used as the material for the piezoelectric layer 563, and ZrO is used as the material for the second layer 552 of the diaphragm 550... X When this is used, if the seed layer 130 on top of the second layer 552 is too thick, the crystallinity of the piezoelectric layer 563 may decrease, contrary to the usual case. Therefore, if the seed layer 130 in the non-active part is formed to be the same thickness as or greater than the seed layer 130 in the active part, the piezoelectric layer 563 is directly laminated on the diaphragm 550 in the non-active part, resulting in extremely low crystallinity of the piezoelectric layer 563. As a result, cracks may occur in the same way as when the piezoelectric layer 563 in the non-active part is unoriented.

[0064] For these reasons, by making the thickness t2 thicker than the thickness t1, the decrease in the crystallinity of the piezoelectric layer 563 in the non-active portion as described above is reduced, and the crystallinity of both the first region A1 and the second region A2 of the piezoelectric layer 563 can be suitably improved.

[0065] Furthermore, from the viewpoint of more favorably enhancing the crystallinity of both the first region A1 and the second region A2 of the piezoelectric layer 563, the thickness t2 of the portion of the seed layer 130 corresponding to the second region A2 is preferably 1.2 times or more and 1.8 times or less the thickness t1 of the portion of the seed layer 130 corresponding to the first region A1, and more preferably 1.4 times or more and 1.6 times or less the thickness t1.

[0066] Conversely, if the ratio of thicknesses t1 to t2 (t2 / t1) is too small, depending on the combination of materials for the piezoelectric layer 563 and the second layer 552 of the diaphragm 550, the thickness t2 may be too thin, leading to a decrease in the orientation of the second region A2, or the thickness t1 may be too thick, leading to a decrease in the orientation of the first region A1. On the other hand, if the ratio (t2 / t1) is too large, depending on the combination of materials for the piezoelectric layer 563 and the second layer 552 of the diaphragm 550, the thickness t2 may be too thick, leading to a decrease in the driving efficiency of the piezoelectric element 560, or the thickness t1 may be too thin, leading to a decrease in the orientation of the first region A1.

[0067] It is preferable that the thickness t3 of the seed layer 130 corresponding to the third region A3 is thinner than the thickness t1 of the seed layer 130 corresponding to the first region A1. This allows for the alignment of the grain boundaries between the first region A1 or the second region A2 and the third region A3. Conversely, if the thickness t3 is too thick, the presence of the taper of region F3 in the third region A3 increases the orientation of the third region A3 too much, causing the grain boundaries between the first region A1 or the second region A2 and the third region A3 to collapse.

[0068] When the piezoelectric layer 563 described above is analyzed by X-ray diffraction (XRD) in the Z1 direction, the first region A1 and the second region A2 each preferentially align with the first crystal orientation. That is, the first region A1 and the second region A2 preferentially align with the same crystal orientation. Therefore, the orientation of the crystal orientations of the first region A1 and the second region A2 do not differ excessively. As a result, differences in physical properties such as Young's modulus and thermal expansion coefficient due to the difference in crystal orientation between the first region A1 and the second region A2 of the piezoelectric layer 343 are suppressed. Therefore, the risk of cracks occurring between the first region A1 and the second region A2 due to the difference in physical properties is suppressed. Consequently, a decrease in discharge performance and durability can be suppressed.

[0069] In this embodiment, the first plane orientation is the (100) plane. That is, the first region A1 and the second region A2 preferentially align with the (100) plane. Therefore, compared to the case where the plane orientation is preferentially aligned with other crystal plane orientations, the ejection characteristics of the piezoelectric element 34 in this embodiment can be improved. Note that the first plane orientation may be other than the (100) plane, such as the (111) plane.

[0070] Furthermore, the degree of orientation towards the first plane orientation in the second region A2 is preferably high, and more preferably 1.1 to 1.5 times the degree of orientation towards the first plane orientation in the first region A1. This is because the second region A2 is the region where voltage is actually applied and strain is generated, so we want to increase the degree of orientation towards the first plane orientation to improve the displaceability of the piezoelectric element 560. In addition, the degree of orientation towards the first plane orientation in the first region A1 does not need to be that high. Rather, if the orientation towards the first plane orientation, especially the (100) plane, is too high, cracks may occur at the grain boundaries when a sufficiently high voltage is applied, resulting in a lower dielectric strength. Considering this point, it is better not to make the orientation towards the first plane orientation in the first region A1 excessively high. From these points, it can be seen that it is preferable to make the degree of orientation towards the first plane orientation in the second region A2 higher than the degree of orientation towards the first plane orientation in the first region A1.

[0071] Figure 7 shows the orientation of the second region A2 of the piezoelectric layer 563. Figure 8 shows the orientation of the first region A1 of the piezoelectric layer 563. Figure 7 shows the results of X-ray diffraction (XRD) analysis of the second region A2 of the piezoelectric layer 563 in the Z1 direction. Figure 8 shows the results of X-ray diffraction (XRD) analysis of the first region A1 of the piezoelectric layer 563 in the Z1 direction. Note that the results shown in Figures 7 and 8 are for the case where the piezoelectric layer 563 is composed of KNN and the constituent material of the seed layer 130 is a composite oxide having a perovskite structure containing Bi, Pb, Fe, and Ti.

[0072] As shown in Figures 7 and 8, the first region A1 and the second region A2 are each preferentially oriented to the (100) plane, and the difference in orientation between the first region A1 and the second region A2 is small.

[0073] 1-4: Method for manufacturing a liquid dispensing head Figures 9 and 10 are explanatory diagrams of the manufacturing method of the liquid discharge head 50 according to the first embodiment. The manufacturing method of the liquid discharge head 50 is carried out in the order of steps ST1 to ST6, as shown in Figures 9 and 10. Each step will be described in order below.

[0074] Step ST1 involves applying a layer 561A, which is made of the material for the first electrode 561, onto the diaphragm 550. More specifically, in step ST1, for example, after forming the diaphragm 550, a bonding layer 140A is uniformly formed on the second layer 552 by sputtering a metal such as titanium, and then a layer 561A is uniformly formed on the bonding layer 140A by sputtering a metal such as platinum.

[0075] Step ST2, after step ST1, patterns the layer 561A formed from the material of the first electrode 561. More specifically, step ST2 patterns the layer 561A using known processing techniques such as photolithography and etching. This forms the patterned first electrode 561. At this time, the adhesion layer 140A is patterned, thereby forming the adhesion layer 140.

[0076] Step ST3 involves applying a layer 13A, formed from the material of the seed layer 130, onto the diaphragm 550 and the first electrode 561 after step ST2. More specifically, step ST3 forms the layer 13A by applying a solution such as a MOD solution containing the precursor material of the seed layer 130 across the diaphragm 550 and the first electrode 561 using a spin-coating method or the like. Here, the thickness of the layer 13A is greater than or equal to the thickness of the seed layer 130 in both the portion corresponding to the first region A1 and the portion corresponding to the second region A2.

[0077] Step ST4 involves heat-treating layer 13A after step ST3. More specifically, in step ST4, for example, layer 13A is dried and degreased at approximately 350°C in an oven, and then heat-treated at approximately 750°C for approximately 5 minutes using an RTA, etc. This forms layer 13B, in which the precursor constituting layer 13A is crystallized by firing. Here, the thickness of layer 13B is greater than or equal to the thickness of seed layer 130 in both the portion corresponding to the first region A1 and the portion corresponding to the second region A2. Note that the heat treatment conditions are not limited to the above example and can be changed as appropriate.

[0078] Step ST5, after step ST4, forms a seed layer 130 by patterning a portion of layer 13B. More specifically, step ST5 thins at least the portion of layer 13B corresponding to the first region A1 using known processing techniques such as photolithography and etching. This forms a seed layer 130 with the aforementioned thicknesses t1 and t2.

[0079] Step ST6 involves applying a piezoelectric material onto the seed layer 130 after step ST5. More specifically, in step ST6, a precursor layer of the piezoelectric layer 563 is formed by applying a solution such as a MOD solution containing a piezoelectric precursor material onto the seed layer 130 using a spin coating method, for example. After drying and degreasing the precursor layer at approximately 350°C in an oven, the precursor layer is then heat-treated at approximately 750°C for approximately 5 minutes using an RTA, etc. This forms the piezoelectric layer 563. The application and heat treatment of the piezoelectric material may be performed in multiple steps. Furthermore, the conditions for the heat treatment are not limited to the above example and can be changed as appropriate.

[0080] After step ST6 described above, the piezoelectric layer 563 is patterned by known processing techniques such as photolithography and etching, although not shown in the diagram. At this time, a portion of the seed layer 130 is also removed by patterning so that the planar shape of the seed layer 130 matches the planar shape of the piezoelectric layer 563. This gives rise to the piezoelectric element 560. Subsequently, the liquid discharge head 50 is obtained through appropriate known processes. Note that the patterning of the piezoelectric layer 563 is performed, for example, after the formation of the pressure chamber C1 on the pressure chamber substrate 520.

[0081] 2. Second Embodiment The following describes a second embodiment of this disclosure. For elements whose operation and function are the same as in the first embodiment in the embodiments described below, the reference numerals used in the description of the first embodiment will be reused, and detailed descriptions of each will be omitted as appropriate.

[0082] Figure 11 is a cross-sectional view of the liquid discharge head 50A according to the second embodiment. The liquid discharge head 50A is configured in the same way as the liquid discharge head 50 of the first embodiment, except that it is equipped with a seed layer 130A instead of the seed layer 130 of the first embodiment.

[0083] The seed layer 130A includes a first seed layer 131 and a second seed layer 132. The first seed layer 131 is not located in the first region A1, but is located in the second region A2. The second seed layer 132 is placed on top of the first seed layer 131 and spans both the first region A1 and the second region A2. By including the first seed layer 131 and the second seed layer 132 in this way, the seed layer 130A has the advantage of making it easier to achieve the desired thicknesses t1 and t2.

[0084] Each of these first seed layer 131 and second seed layer 132 is composed of a material capable of controlling the orientation of the piezoelectric layer 563 as described above. Here, since the second seed layer 132 is arranged across both the first region A1 and the second region A2, the orientation of the piezoelectric layer 563 can be controlled in both the active and inactive parts. Therefore, the occurrence of damage such as cracks caused by differences in the orientation of the piezoelectric layer 563 between the active and inactive parts can be reduced.

[0085] Furthermore, since the second seed layer 132 is provided on top of the first seed layer 131, it is formed after the formation of the first seed layer 131, as will be described in detail later. Also, the first seed layer 131 can be heat-treated before patterning the first electrode 561 and the first seed layer 131. During this heat treatment, diffusible materials in layers such as the adhesion layer 140 directly beneath the first electrode 561 cannot diffuse laterally but diffuse in the thickness direction. Therefore, the materials in layers such as the adhesion layer 140 do not precipitate in a concentrated area during this heat treatment. In addition, the second seed layer 132 is heat-treated after patterning the first seed layer 131, but by this time, the diffusible materials in layers such as the adhesion layer 140 have completely diffused. Therefore, the materials in layers such as the adhesion layer 140 do not precipitate in a concentrated area at the edge of the first electrode 561 during this heat treatment. From the above, the occurrence of damage such as cracks caused by localized segregation of materials in layers such as the adhesion layer 140 can also be reduced.

[0086] In this case, if the first electrode 561 contains Ir, the Ir contained in the first electrode 561 is easily diffused by heat treatment. Therefore, in this case, using the first seed layer 131 and the second seed layer 132 significantly reduces the occurrence of local segregation of the material in layers such as the adhesion layer 140.

[0087] Furthermore, if the piezoelectric layer 563 contains K, Na, and Nb, and the piezoelectric layer 563 does not contain Ti, then if the first electrode 561 contains Ti, the affinity between the first electrode 561 and the piezoelectric layer 563 will be low. Therefore, if Ti diffuses from layers such as the adhesion layer 140, the Ti will precipitate on the edge of the first electrode 561 without entering the piezoelectric layer 563. Consequently, in this case, using the first seed layer 131 and the second seed layer 132 significantly reduces the occurrence of local segregation of the material in layers such as the adhesion layer 140.

[0088] The first seed layer 131 is not disposed in the third region A3, whereas the second seed layer 132 is also disposed in the third region A3. Thereby, the orientation of the third region A3 can be enhanced. Here, when the first electrode 561 and the first seed layer 131 are formed by a collective patterning, the first seed layer 131 cannot be formed in the region F3 of the first electrode 561. If the seed layer 130A does not exist in the region F3, the third region A3 between the first region A1 and the second region A2 becomes non-oriented, so that a large difference in orientation occurs between these regions, and as a result, there is a risk of crack generation. On the other hand, by providing the second seed layer 132 on the region F3, the orientation of the third region A3 can be enhanced. As a result, by reducing the difference in orientation between these regions, the occurrence of cracks can be reduced.

[0089] When the thickness of the first seed layer 131 in the second region A2 is a, the thickness of the second seed layer 132 in the second region A2 is b, and the thickness of the second seed layer 132 in the first region A1 is c, a + b > c is satisfied. Thereby, the thickness t2 can be made thicker than the thickness t1.

[0090] When the thickness of the second seed layer 132 in the second region A2 is b and the thickness of the second seed layer 132 in the first region A1 is c, it is preferable that b < c is satisfied. Thereby, it is possible to prevent the thickness of the seed layer 130A in the second region A2 from becoming unnecessarily thick. As a result, optimization of the orientation control of the piezoelectric layer 563 is achieved in both the active part and the passive part. Here, in the active part, since the first seed layer 131 exists, the orientation control of the piezoelectric layer 563 can be performed by the first seed layer 131. On the other hand, in the passive part, since the first seed layer 131 does not exist, it is necessary to perform the orientation control of the piezoelectric layer 563 by the second seed layer 132. Therefore, by making the thickness c of the second seed layer 132 in the first region A1 thicker than the thickness b of the second seed layer 132 in the second region A2, in other words, by satisfying b < c, optimization of the orientation control of the piezoelectric layer 563 is achieved in both the active part and the passive part.

[0091] On the other hand, if the thickness c of the second seed layer 132 in the first region A1 is made smaller than the thickness b of the second seed layer 132 in the second region A2, the thickness of the seed layer 130A in the active part becomes too thick in controlling the orientation of the piezoelectric layer 563 in both the active part and the passive part. As a result, an increase in the electrical resistance of the seed layer 130A in the active part causes a problem in that the discharge characteristics deteriorate due to a decrease in conductivity between the first electrode 561 and the piezoelectric layer 563.

[0092] When the thickness of the first seed layer 131 in the second region A2 is a, the thickness of the second seed layer 132 in the second region A2 is b, and the thickness of the second seed layer 132 in the first region A1 is c, it is preferable that b < a < c and a + b > c. This makes it possible to satisfy b < c and a + b > c so that the difference between the thicknesses (a + b) and c does not become too large.

[0093] The first seed layer 131 and the second seed layer 132 are each in contact with the first electrode 561 at least in part. Such a first seed layer 131 and second seed layer 132 can be obtained by forming the second seed layer 132 after forming the first seed layer 131.

[0094] The first seed layer 131 and the second seed layer 132 are preferably made of the same material as each other. This can increase the adhesion between the first seed layer 131 and the second seed layer 132 by enhancing the affinity between them. As a result, peeling between the first seed layer 131 and the second seed layer 132 can be reduced. On the other hand, if the first seed layer 131 and the second seed layer 132 are made of different materials from each other, the affinity between the first seed layer 131 and the second seed layer 132 may deteriorate, and peeling between the first seed layer 1 and the second seed layer 132 may occur due to the deterioration of the adhesion between them.

[0095] The first seed layer 131 and the second seed layer 132 preferably each contain Ti. This makes it possible to realize the first seed layer 131 and the second seed layer 132 that can suitably control the orientation of the piezoelectric layer 563.

[0096] The first seed layer 131 and the second seed layer 132 preferably contain Bi, Fe, Ti, and Pb, respectively. This allows the seed layer 130A to be constructed with a composite oxide having a perovskite structure, thereby suitably improving the orientation of the piezoelectric layer 563.

[0097] When both the first seed layer 131 and the second seed layer 132 are provided, the second seed layer 132 is present in both the first region A1 and the second region A2. As a result, both the first region A1 and the second region A2 are preferentially oriented to the (100) plane, and the orientation states of the first region A1 and the second region A2 are very similar to each other. Thus, when both the first seed layer 131 and the second seed layer 132 are provided, the first region A1 and the second region A2 preferentially oriented to the same crystal plane orientation.

[0098] In contrast, if only the first seed layer 131 is provided, the first seed layer 131 is present only in the second region A2. As a result, the second region A2 preferentially aligns to the (100) plane, while the first region A1 does not preferentially align to the (100) plane. Furthermore, in this case, the difference in orientation between the first region A1 and the second region A2 is significant.

[0099] 1-4: Method for manufacturing a liquid dispensing head Figures 12 and 13 are explanatory diagrams of the manufacturing method of the liquid discharge head 50A according to the second embodiment. The manufacturing method of the liquid discharge head 50A is carried out in the order of steps ST1A to ST7A, as shown in Figures 12 and 13. Each step will be described in order below.

[0100] Step ST1A is similar to step ST1 of the first embodiment, in which a layer 561A formed from the material of the first electrode 561 is applied onto the diaphragm 550.

[0101] Step ST2A involves applying a layer 131A, formed from the material of the first seed layer 131, onto a layer 561A, formed from the material of the first electrode 561, after step ST1A. More specifically, step ST2A forms layer 131A, which is a precursor layer of the first seed layer 131, by applying a solution such as a MOD solution containing the precursor material of the first seed layer 131 onto layer 561A using a spin coating method or the like.

[0102] Step ST3A, following step ST2A, heat-treats layer 131A, which is formed from the material of the first seed layer 131. More specifically, in step ST3A, for example, layer 131A, which is the precursor layer of the first seed layer 131, is dried and degreased at approximately 350°C using an oven or the like, and then heat-treated at approximately 750°C for approximately 5 minutes using RTA (rapid thermal annealing) or the like. This forms layer 131B, in which the precursor constituting layer 131A is crystallized by firing. Note that the conditions for the heat treatment are not limited to the example described above and can be changed as appropriate.

[0103] Step ST4A, following step ST3A, patterns layer 561A, formed from the material of the first electrode 561, and layer 131B, formed from the material of the first seed layer 131. More specifically, step ST4A patterns layer 561A and layer 131B together using known processing techniques such as photolithography and etching. This forms the patterned first electrode 561 and the patterned first seed layer 131. At this time, the adhesion layer 140A is patterned, thereby forming the adhesion layer 140.

[0104] Step ST5A, after step ST4A, coats layer 132A, which is made of the material for the second seed layer 132, onto the diaphragm 550 and the first seed layer 131 (a layer made of the material for the first seed layer 131). More specifically, step ST5A forms layer 132A, which is a precursor layer for the second seed layer 132, by applying a solution such as a MOD solution containing the precursor material for the second seed layer 132 across the diaphragm 550 and the first seed layer 131 using a spin-coating method or the like.

[0105] Step ST6A, following step ST5A, heat-treats layer 132A, which is formed from the material of the second seed layer 132. More specifically, in step ST6A, for example, layer 132A, which is the precursor layer of the second seed layer 132, is dried and degreased at approximately 350°C in an oven or the like, and then heat-treated at approximately 750°C for approximately 5 minutes using an RTA or the like. This forms the second seed layer 132, in which the precursor constituting layer 132A is crystallized by firing. Note that the conditions for the heat treatment are not limited to the example described above and can be changed as appropriate. Also, the temperature, time, and other conditions for the heat treatment in step ST6A may be the same as or different from the conditions for the heat treatment in step ST3A.

[0106] Step ST7A involves applying a piezoelectric material onto the second seed layer 132 (a layer formed from the material of the second seed layer 132) after step ST6A. More specifically, in step ST7A, for example, a precursor layer of the piezoelectric layer 563 is formed by applying a solution such as a MOD solution containing a piezoelectric precursor material onto the second seed layer 132 using a spin coating method or the like. After that, the precursor layer is dried and degreased at approximately 350°C in an oven or the like, and then heat-treated at approximately 750°C for approximately 5 minutes using an RTA or the like. This forms the piezoelectric layer 563. Note that the application and heat treatment of the piezoelectric material may be performed in multiple steps. Furthermore, the conditions for the heat treatment are not limited to the above example and can be changed as appropriate.

[0107] After step ST7A described above, the piezoelectric layer 563 is patterned by known processing techniques such as photolithography and etching, although not shown in the diagram. At this time, a portion of the second seed layer 132 is also removed by patterning so that its planar shape matches the planar shape of the piezoelectric layer 563. This yields the piezoelectric element 560. Subsequently, the liquid discharge head 50 is obtained through appropriate known processes. Note that the patterning of the piezoelectric layer 563 is performed, for example, after the formation of the pressure chamber C1 on the pressure chamber substrate 520.

[0108] In the above method for manufacturing the liquid discharge head 50, the heat treatment in step ST3A is performed before the patterning in step ST4A. During this heat treatment, diffusible materials such as Ti in the layers such as the adhesion layer 140A directly below the layer 561A cannot diffuse laterally but diffuses in the thickness direction. Therefore, during this heat treatment, the materials of the layers such as the adhesion layer 140A do not precipitate in a concentrated area. Furthermore, after the patterning in step ST4A, a heat treatment for the second seed layer 132 is performed in step ST6A, but by the time of this heat treatment, the diffusible materials in the layers such as the adhesion layer 140 have already diffused completely in step ST3A. Therefore, during this heat treatment, the materials of the layers such as the adhesion layer 140 do not precipitate in a concentrated area at the end of the first electrode 561. As a result, the occurrence of cracks caused by localized segregation of the materials in the layers such as the adhesion layer 140 can also be reduced.

[0109] 3: Variant Each of the forms exemplified above can be modified in various ways. Specific examples of modifications that can be applied to each of the aforementioned forms are given below. Any form selected from the following examples can be combined as appropriate, provided they do not contradict each other.

[0110] 3-1: Variation 1 In the embodiments described above, an example is shown in which the second electrode 562 is a common electrode. However, the embodiment is not limited to this example, and the second electrode 562 may be an individual electrode for each piezoelectric element 650. In this case, the first electrode 561 may be a common electrode common to multiple piezoelectric elements 560. However, even when the first electrode 561 is a common electrode and the second electrode 562 is an individual electrode, the piezoelectric layer 563 includes a region that does not overlap with the first electrode 561.

[0111] 3-2: Variation 2 In the embodiments described above, a serial-type liquid dispensing device 100 was exemplified, in which a transporter 41 equipped with a liquid dispensing head 50 is moved back and forth. However, this disclosure also applies to a line-type liquid dispensing device in which multiple nozzles N are distributed across the entire width of the recording medium M.

[0112] 3-3: Modification 3 The liquid dispensing device 100 exemplified in the above-described form may be used in various devices such as facsimile machines and photocopiers, in addition to equipment dedicated to printing, and the applications of this disclosure are not particularly limited. However, the applications of the liquid dispensing device are not limited to printing. For example, a liquid dispensing device that dispenses a colorant solution can be used as a manufacturing device for forming color filters for display devices such as liquid crystal display panels. A liquid dispensing device that ejects a conductive material solution can be used as a manufacturing device for forming wiring and electrodes on a wiring board. A liquid dispensing device that ejects a solution of organic matter related to living organisms can be used, for example, as a manufacturing device for producing biochips. [Explanation of symbols]

[0113] 10...Liquid container, 13A...Layer, 13B...Layer, 20...Control module (control unit), 30...Transport mechanism, 34...Piezoelectric element, 40...Moving mechanism, 41...Transport body, 42...Transport belt, 50...Liquid discharge head, 50A...Liquid discharge head, 100...Liquid discharge device, 110...First wiring, 120...Second wiring, 121...Conductive layer, 122...Conductive layer, 130...Seed layer, 130A...Seed layer, 131...First seed D layer, 131A... layer, 131B... layer, 132... second seed layer, 132A... layer, 140... adhesion layer, 140A... adhesion layer, 343... piezoelectric layer, 510... communicating substrate, 520... pressure chamber substrate, 530... nozzle plate, 540... vibration absorber, 550... diaphragm, 551... first layer, 552... second layer, 560... piezoelectric element, 561... first electrode, 561A... layer, 561b... adhesion layer, 562... second electrode, 563... Piezoelectric layer, 570…protective substrate, 580…case, 590…wiring board, 600…drive circuit, 650…piezoelectric element, A1…first region, A2…second region, A3…third region, C1…pressure chamber, Com…drive signal, F1…region, F2…region, F3…region, FN…nozzle surface, G…notch, HL…inlet, Ln1…first nozzle row, Ln2…second nozzle row, M…recording medium, N…nozzle, Na…communication channel, R...reservoir, R1...flow channel, R2...flow channel, Ra...supply flow channel, S...space, SI...control signal, ST1...process, ST1A...process, ST2...process, ST2A...process, ST3...process, ST3A...process, ST4...process, ST4A...process, ST5...process, ST5A...process, ST6...process, ST6A...process, ST7A...process, b...thickness, c...thickness, t1...thickness, t2...thickness, t3...thickness, α...part.

Claims

1. A pressure chamber substrate having a plurality of pressure chambers arranged in a first direction, A diaphragm placed on the pressure chamber substrate, A first electrode placed on the diaphragm, A piezoelectric layer disposed on the first electrode, A second electrode disposed on the piezoelectric layer, A liquid dispensing head having a seed layer located between the piezoelectric layer and the diaphragm for controlling the orientation of the piezoelectric layer, The piezoelectric layer has a first region that does not overlap with the first electrode in the first direction, and a second region that overlaps with the first electrode in the first direction. A liquid dispensing head characterized in that the thickness of the portion of the seed layer corresponding to the second region is greater than the thickness of the portion of the seed layer corresponding to the first region.

2. The liquid discharge head according to claim 1, characterized in that the thickness of the portion of the seed layer corresponding to the second region is 1.2 times or more and 1.8 times or less the thickness of the portion of the seed layer corresponding to the first region.

3. The liquid discharge head according to claim 2, characterized in that the thickness of the portion of the seed layer corresponding to the second region is 1.4 times or more and 1.6 times or less the thickness of the portion of the seed layer corresponding to the first region.

4. The liquid dispensing head according to claim 1, characterized in that the seed layer is composed of a single layer arranged across both the first region and the second region.

5. The aforementioned seed layer, A first seed layer is not located in the first region but is located in the second region, The liquid dispensing head according to claim 1, further comprising a second seed layer provided on the first seed layer and positioned across both the first and second regions.

6. When the piezoelectric layer is analyzed by X-ray diffraction, the first region is preferentially oriented in the first plane orientation, and the second region is preferentially oriented in the first plane orientation. The liquid dispensing head according to claim 1, characterized in that the degree of orientation to the first surface orientation in the second region is higher than the degree of orientation to the first surface orientation in the first region.

7. The liquid discharge head according to claim 6, characterized in that the degree of orientation to the first surface orientation in the second region is 1.1 times or more and 1.5 times or less the degree of orientation to the first surface orientation in the first region.

8. The liquid discharge head according to claim 6, characterized in that the first plane orientation is (100).

9. The liquid dispensing head according to claim 1, characterized in that the piezoelectric layer contains K, Na, and Nb.

10. The liquid dispensing head according to claim 1, characterized in that the piezoelectric layer contains Pb, Zr, and Ti.

11. The first region is a region that is stacked on top of a region of the upper surface of the diaphragm that is flat along the first direction, The liquid dispensing head according to claim 1, characterized in that the second region is a region stacked on top of a region of the upper surface of the first electrode that is flat along the first direction.

12. The piezoelectric layer further includes a third region located between the first region and the second region in the first direction, The liquid dispensing head according to claim 11, characterized in that the third region is stacked on a region of the upper surface of the first electrode that is inclined with respect to the first direction.

13. The liquid dispensing head according to claim 12, characterized in that the thickness of the portion of the seed layer corresponding to the third region is thinner than the thickness of the portion of the seed layer corresponding to the first region.

14. A liquid dispensing head according to any one of claims 1 to 13, A liquid dispensing device characterized by having a control unit that controls the dispensing operation from the liquid dispensing head.

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