Liquid nozzle, liquid ejection device, and method for manufacturing liquid nozzle

Abstract

This invention relates to a liquid ejector head, a liquid ejection device, and a method for manufacturing a liquid ejector head. It can reduce damage such as cracks. The liquid ejector head includes: a pressure chamber substrate having a plurality of pressure chambers arranged in a first direction; a vibrating plate disposed on the pressure chamber substrate; a first electrode disposed on the vibrating plate; 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 vibrating plate 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. The seed layer includes: a first seed layer disposed in the second region but not in the first region; and a second seed layer disposed on the first seed layer and spanning both the first and second regions.

Description

Technical Field

[0001] This disclosure relates to a liquid ejector head, a liquid ejection device, and a method for manufacturing a liquid ejector head. Background Technology

[0002] In a liquid ejector head in which a vibrating plate, a first electrode, a piezoelectric layer, and a second electrode are sequentially stacked on a pressure chamber substrate having multiple pressure chambers, a seed layer for controlling the orientation of the piezoelectric layer is sometimes provided between the piezoelectric layer and the vibrating plate. For example, Patent Document 1 describes forming a piezoelectric layer on the seed layer after uniformly forming a monolayer seed layer on the patterned first electrode.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-37932 In the configuration of Patent Document 1, due to the heat treatment during the formation of the seed layer, the material contained in the layer directly below the first electrode will concentrate and precipitate at the end of the first electrode. If such localized material segregation occurs, oxides will form, and the piezoelectric layer will lift up at the end of the first electrode, which may result in cracks. Summary of the Invention

[0004] To address the above technical problems, the preferred aspect of this disclosure relates to a liquid ejector head, characterized in that the liquid ejector head comprises: a pressure chamber substrate having a plurality of pressure chambers arranged in a first direction; a vibrating plate disposed on the pressure chamber substrate; a first electrode disposed on the vibrating plate; 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 vibrating plate for controlling the orientation of the piezoelectric layer, the piezoelectric layer having: 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, the seed layer comprising: a first seed layer disposed in the second region but not in the first region; and a second seed layer disposed on the first seed layer and spanning both the first region and the second region.

[0005] The liquid ejection device according to a preferred aspect of this disclosure is characterized by comprising: a liquid ejection head as described in the aspect; and a control unit for controlling the ejection action from the liquid ejection head.

[0006] The preferred aspect of this disclosure relates to a method for manufacturing a liquid ejector head, characterized in that the liquid ejector head comprises: a pressure chamber substrate having a plurality of pressure chambers arranged in a first direction; and a vibrating plate disposed on the pressure chamber substrate. In the method for manufacturing the liquid ejector head, the following steps are performed sequentially: coating a layer formed of a material of a first electrode onto the vibrating plate; coating a layer formed of a material of a first seed layer onto the layer formed of the material of the first electrode; heat-treating the layer formed of the material of the first seed layer; patterning the layer formed of the material of the first electrode and the layer formed of the material of the first seed layer; coating a layer formed of a material of a second seed layer onto the vibrating plate and the layer formed of the material of the first seed layer; heat-treating the layer formed of the material of the second seed layer; and coating a piezoelectric element onto the layer formed of the material of the second seed layer. Attached Figure Description

[0007] Figure 1 This is a simplified diagram illustrating an example configuration of the liquid ejection device according to the embodiment.

[0008] Figure 2 This is an exploded perspective view of the liquid ejector head according to the first embodiment.

[0009] Figure 3 yes Figure 2 The AA line cross-section diagram.

[0010] Figure 4 yes Figure 2 A top view of a portion of the liquid ejector head shown.

[0011] Figure 5 yes Figure 4 BB line cross-section diagram.

[0012] Figure 6 yes Figure 5 A magnified view of part α in the image.

[0013] Figure 7 This is an explanatory diagram of the manufacturing method of the liquid nozzle involved in the embodiment.

[0014] Figure 8 This is an explanatory diagram of the manufacturing method of the liquid nozzle involved in the embodiment.

[0015] Figure 9 This is an explanatory diagram of the manufacturing method of the liquid nozzle involved in Comparative Example 1.

[0016] Figure 10 This is an explanatory diagram of the manufacturing method of the liquid nozzle involved in Comparative Example 2.

[0017] Explanation of reference numerals in the attached figures 10: Liquid container; 20: Control module (control unit); 30: Conveying mechanism; 40: Moving mechanism; 41: Conveying body; 42: Conveyor belt; 50: Liquid nozzle; 50X: Liquid nozzle; 50Y: Liquid nozzle; 100: Liquid spraying device; 110: First wiring; 120: Second wiring; 121: Conductive layer; 122: Conductive layer; 130: Seed layer; 130X: Seed layer; 130Y: Seed layer; 131: First seed layer Layer; 131A: Layer; 131B: Layer; 132: Second seed layer; 132A: Layer; 140: Sealing layer; 140A: Sealing layer; 510: Connecting substrate; 520: Pressure chamber substrate; 530: Nozzle plate; 540: Vibration absorber; 550: Vibrating plate; 551: First layer; 552: Second layer; 560: Piezoelectric element; 561: First electrode; 561A: Layer; 561b: Sealing layer; 562: Second electrode; 563: Piezoelectric element Layer; 570: Protective substrate; 580: Housing; 590: Wiring substrate; 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 face; G: Cutout; HL: Inlet; Ln1: First nozzle row; Ln2: Second nozzle row; M: Recording medium; N: Nozzle; Na: Connector Flow path; R: Memory; R1: Flow path; R2: Flow path; Ra: Supply flow path; S: Space; SI: Control signal; ST1: Process; ST2: Process; ST2X: Process; ST3: Process; ST3X: Process; ST4: Process; ST4X: Process; ST5: Process; ST5X: Process; ST5Y: Process; ST6: Process; ST6Y: Process; ST7: Process; a: Thickness; b: Thickness; c: Thickness; α: Part. Detailed Implementation

[0018] The following is a reference to the appendix. Figure 1 The preferred embodiments involved in this disclosure will be described below. It should be noted that the dimensions and scales of the parts in the accompanying drawings differ appropriately from the actual dimensions, and some parts are shown schematically for ease of understanding. Furthermore, unless otherwise specified in the following description, the scope of this disclosure is not limited to these embodiments.

[0019] It should be noted that, for convenience, the following explanation will use intersecting X-axis, Y-axis, and Z-axis. Furthermore, in the following explanation, one direction along the X-axis is the X1 direction, and the opposite 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 the "first direction." Additionally, opposite directions along the Z-axis are the Z1 and Z2 directions. The Z1 direction is an example of the "second direction." Hereinafter, observation along the Z1 or Z2 direction will sometimes be referred to as "top-down observation."

[0020] Here, the Z-axis is typically a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. However, the Z-axis may not be a vertical axis. In addition, the X-axis, Y-axis, and Z-axis are typically orthogonal to each other, but are not limited to this; for example, they can intersect at an angle between 80° and 100°.

[0021] 1: First Implementation Method 1-1: Overall Composition of the Liquid Ejection Device Figure 1 This is a simplified diagram illustrating an example configuration of the liquid ejection device 100 according to the embodiment. The liquid ejection device 100 is an inkjet printing apparatus that ejects ink, an example of a "liquid," as droplets onto a recording medium M. The recording medium M is typically printing paper. It should be noted that the recording medium M is not limited to printing paper; for example, it can be any printing material such as resin film or cloth.

[0022] like Figure 1 As shown, the liquid ejection device 100 includes a liquid container 10, a control module 20, a conveying mechanism 30, a moving mechanism 40, and multiple liquid ejection heads 50. The control module 20 is an example of a "control unit".

[0023] Liquid container 10 stores ink. Specific examples of liquid container 10 include, for instance, a box detachable from the liquid dispensing device 100, a bag-shaped ink pouch made of a flexible membrane, and an ink canister for refilling ink. It should be noted that the type of ink stored in liquid container 10 is arbitrary.

[0024] The control module 20 controls the operation of various elements of the liquid dispensing device 100. The control module 20 includes, for example, processing circuits such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array) and storage circuits such as semiconductor memory. Here, the control module 20 outputs a drive signal Com for driving the liquid dispensing head 50 and a control signal SI for controlling the drive of the liquid dispensing head 50. The control module 20 controls the dispensing action from the liquid dispensing head 50 through these drive signal Com and control signal SI.

[0025] Under the control of the control module 20, the conveying mechanism 30 conveys the recording medium M along the Y-axis.

[0026] The moving mechanism 40, under the control of the control module 20, causes the liquid nozzle 50 to reciprocate along the X-axis. The moving mechanism 40 has a generally box-shaped conveyor body 41, called a carriage, that houses the liquid nozzle 50, and an annular conveyor belt 42 to which the conveyor body 41 is fixed. It should be noted that, in addition to the liquid nozzle 50, the liquid container 10 may also be mounted in the conveyor body 41.

[0027] Under the control of the control module 20, multiple liquid ejector heads 50 eject ink supplied from the liquid container 10 from multiple nozzles N onto the recording medium M. This ejection is performed in parallel with the transport of the recording medium M by the transport mechanism 30 and the reciprocating movement of the liquid ejector heads 50 by the moving mechanism 40, thereby forming an ink image on the surface of the recording medium M.

[0028] exist Figure 1 In the example shown, there are four liquid nozzles 50. It should be noted that the number of liquid nozzles 50 is not limited to [specific number]. Figure 1 The example shown is not arbitrary; it can be a single head, or multiple heads of three or fewer, or more than five. Furthermore, the configuration of multiple liquid nozzles 50 is not limited to... Figure 1 The example shown is not arbitrary.

[0029] 1-2: Liquid ejector head Figure 2 This is an exploded perspective view of the liquid ejector head 50 according to the first embodiment. Figure 3 yes Figure 2 The diagram shows a cross-sectional view along line AA. Below, an example of the configuration of the liquid ejector head 50 will be explained.

[0030] like Figure 2 and Figure 3 As shown, the liquid ejector head 50 has a plurality of nozzles N arranged in the direction along the Y-axis.

[0031] The liquid ejector head 50 has a plurality of nozzles N, which are divided into a first nozzle column Ln1 and a second nozzle column Ln2 arranged at intervals along the X-axis. The first nozzle column Ln1 and the second nozzle column Ln2 are each a collection of a plurality of nozzles N arranged in a straight line along the Y-axis.

[0032] The liquid ejector heads 50 are configured to be approximately symmetrical about each other along the X-axis. However, the positions of the nozzles N in the first nozzle array Ln1 and the nozzles N in the second nozzle array Ln2 along the Y-axis may be the same or different. Figure 2 and Figure 3 In the example, the multiple nozzles N of the first nozzle array Ln1 and the multiple nozzles N of the second nozzle array Ln2 are arranged in a configuration where their positions are consistent along the Y-axis.

[0033] like Figure 2 and Figure 3 As shown, the liquid ejector head 50 has a connecting base plate 510, a pressure chamber base plate 520, a nozzle plate 530, a vibration absorber 540, a vibrating plate 550, multiple piezoelectric elements 560, a protective base plate 570, a housing 580, and a wiring base plate 590.

[0034] The connecting substrate 510 and the pressure chamber substrate 520 are sequentially stacked in the Z1 direction to form a flow path for supplying ink to a plurality of nozzles N. A vibrating plate 550, a plurality of piezoelectric elements 560, a protective substrate 570, a housing 580, a wiring substrate 590, and a drive circuit 600 are provided in a region located further in the Z1 direction than the stack formed by the connecting substrate 510 and the pressure chamber substrate 520. On the other hand, a nozzle plate 530 and a vibration absorber 540 are provided in a region located further in the Z2 direction than the stack. The components of the liquid ejector head 50 are generally elongated plate-shaped parts in the Y direction, joined together, for example, by an adhesive. The components of the liquid ejector head 50 will be described in turn below.

[0035] The nozzle plate 530 is a plate-shaped component provided with a plurality of nozzles N, each of a first nozzle row Ln1 and a second nozzle row Ln2. Each nozzle 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, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing techniques such as dry etching or wet etching. However, other known methods and materials can also be appropriately used to manufacture the nozzle plate 530. Furthermore, the cross-sectional shape of the nozzles N is typically circular, but not limited to this; for example, it can also be a non-circular shape such as a polygon or an ellipse.

[0036] On the connecting substrate 510, flow paths R1, multiple supply flow paths Ra, and multiple connecting flow paths Na are provided for the first nozzle array Ln1 and the second nozzle array Ln2, respectively. Flow path R1 is a flow path shared with the multiple nozzles N, communicating with the multiple nozzles N and located upstream of the nozzles N. It is composed of an elongated hole extending in the Y-axis direction when viewed from above along the Z-axis. The supply flow paths Ra and connecting flow paths Na are flow paths composed of through holes formed for each nozzle N. Each supply flow path Ra is connected to flow path R1.

[0037] The connecting substrate 510, like the nozzle plate 530 described above, is manufactured, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing technology. However, other known methods and materials may also be appropriately used in the manufacture of the connecting substrate 510.

[0038] The pressure chamber substrate 520 is a plate-shaped component having a plurality of pressure chambers C1, referred to as cavities, respectively provided for the first nozzle array Ln1 and the second nozzle array Ln2. The plurality of pressure chambers C1 are arranged in the direction along the Y-axis. Each pressure chamber C1 is an elongated space formed for each nozzle N, extending in the direction along the X-axis when viewed from above. As described above, the pressure chamber substrate 520 has a plurality of pressure chambers C1 arranged in either the Y1 or Y2 direction.

[0039] The pressure chamber substrate 520, like the nozzle plate 530 described above, is manufactured, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing technology. However, other known methods and materials can also be appropriately used to manufacture the pressure chamber substrate 520.

[0040] Pressure chamber C1 is located between the connecting substrate 510 and the vibrating plate 550. Multiple pressure chambers C1 are arranged along the Y-axis, respectively, for the first nozzle array Ln1 and the second nozzle array Ln2. Furthermore, pressure chamber C1 is connected to both the connecting flow path Na and the supply flow path Ra. Therefore, pressure chamber C1 is connected to nozzle N via the connecting flow path Na and to flow path R1 via the supply flow path Ra.

[0041] More specifically, a vibrating plate 550 is disposed on the Z1-oriented surface of the pressure chamber substrate 520. The vibrating plate 550 is a plate-shaped component capable of elastic vibration and is vibrated by a piezoelectric element 560. Further details will be based on... Figure 5 Details of the 550 vibrating plate are explained below.

[0042] On the Z1-oriented surface of the vibrating plate 550, multiple piezoelectric elements 560, corresponding to nozzles N, are arranged for the first nozzle array Ln1 and the second nozzle array Ln2, respectively. Each piezoelectric element 560 is a passive element that deforms upon the supply of a potential corresponding to the drive signal Com, causing pressure fluctuations in the ink within the pressure chamber C1. Each piezoelectric element 560, when viewed from above, appears as an elongated strip extending along the X-axis. Multiple piezoelectric elements 560 are arranged along the Y-axis in a manner corresponding to multiple pressure chambers C1. The piezoelectric elements 560 overlap with the pressure chambers C1 when viewed from above. These piezoelectric elements 560 apply pressure to the pressure chamber C1, which is connected to the nozzle N that ejects ink. Then, based on... Figures 4 to 6 Details of piezoelectric element 560 are provided below.

[0043] The protective substrate 570 is a plate-shaped component disposed on the Z1-oriented surface of the vibrating plate 550, protecting the plurality of piezoelectric elements 560 and enhancing the mechanical strength of the vibrating plate 550. Here, the plurality of piezoelectric elements 560 are accommodated in the space S between the protective substrate 570 and the vibrating plate 550. The protective substrate 570 is, for example, made of resin material.

[0044] The housing 580 is a housing for storing ink supplied to multiple pressure chambers C1. The housing 580 is made of, for example, resin material. Flow paths R2 are provided in the housing 580 for the first nozzle array Ln1 and the second nozzle array Ln2, respectively. Flow paths R2 are spaces connected to the aforementioned flow paths R1, and are formed by elongated holes extending in the Y-axis direction when viewed from above along the Z-axis. Flow paths R2 communicate with nozzles N and, together with flow paths R1, function as reservoirs R for storing ink supplied to the multiple pressure chambers C1. Inlet ports HL for supplying ink to each reservoir R are provided in the housing 580. The ink in each reservoir R is supplied to the pressure chamber C1 via each supply flow path Ra. It should be noted that the position and number of inlet ports HL relative to each reservoir R are not limited. Figure 2 and Figure 3 It is not an example, but arbitrary.

[0045] The vibration absorber 540, also known as a flexible substrate, is a flexible resin film that forms the wall of the reservoir R and absorbs pressure fluctuations of the ink within the reservoir R. It should be noted that the vibration absorber 540 can also be a flexible thin sheet of metal. The Z1-oriented surface of the vibration absorber 540 is bonded to the connecting substrate 510 using an adhesive or similar agent.

[0046] The wiring substrate 590 is mounted on the Z1-oriented surface of the vibrating plate 550 and serves as a mounting component for electrically connecting the control module 20 to the liquid ejector head 50. The wiring substrate 590 is, for example, a flexible wiring substrate 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 substrate 590. Under the control of the control module 20, the drive circuit 600 switches between supplying pulses included in the drive signal Com output from the control module 20 to each of the plurality of piezoelectric elements 560 present in the liquid ejector head 50. As described above, the wiring substrate 590 supplies the drive signal Com to drive the piezoelectric elements 560. It should be noted that the wiring substrate 590 can also be a rigid substrate. In this case, the drive circuit 600 is mounted on the rigid substrate or on a flexible substrate connected to the rigid substrate.

[0047] 1-3: Piezoelectric elements Figure 4 yes Figure 2 A top view of a portion of the liquid ejector head 50 shown. Figure 5 yes Figure 4 BB line cross-section diagram. Figure 6 yes Figure 5 A magnified view of part α in the image. It should be noted that in... Figure 4 In order to facilitate observation, the portion of the second electrode 562 that is not covered by the second wiring 120 described later will be shown as a dot.

[0048] The following is based on Figures 4 to 6 The structure of the vibrating plate 550 and the piezoelectric element 560 will be explained.

[0049] The vibrating plate 550 has a first layer 551 and a second layer 552, which are stacked sequentially in the Z1 direction.

[0050] The first layer 551 is, for example, an elastic film made of silicon oxide (SiO2), which is formed by thermal oxidation of one side of a single-crystal silicon substrate. The second layer 552 is, for example, an insulating film made of zirconium oxide (ZrO2), which is formed by sputtering a zirconium layer and then thermally oxidizing that layer.

[0051] It should be noted that the vibrating plate 550 is not limited to the above-described configuration based on the stack of the first layer 551 and the second layer 552. For example, it can be composed of a single layer or three or more layers. Furthermore, the materials constituting each layer of the vibrating plate 550 are not limited to the materials described above; for example, they can be silicon or silicon nitride. For instance, in addition to ZrO2, TiO2, Al2O3, SiO2, SiN, etc., can also be used as the material constituting the second layer 552. Moreover, the thickness relationship between the first layer 551 and the second layer 552 is not limited to the example shown in the figure, but is arbitrary.

[0052] Multiple piezoelectric elements 560 are arranged on the Z1-oriented surface of the vibrating plate 550. For example... Figure 5 As shown, each piezoelectric element 560 has a first electrode 561, a second electrode 562, a piezoelectric layer 563, and a seed layer 130. These are stacked sequentially in the Z1 direction as the first electrode 561, the piezoelectric layer 563, the second electrode 562, and the seed layer 130. Thus, the liquid ejector head 50 has the first electrode 561, the piezoelectric layer 563, the second electrode 562, and the seed layer 130.

[0053] In the piezoelectric element 560, by applying a voltage between the first electrode 561 and the second electrode 562, the piezoelectric layer 563 deforms due to the inverse piezoelectric effect. If the vibrating plate 550 vibrates in conjunction with this deformation, the pressure in the pressure chamber C1 changes, thereby ejecting ink from the nozzle N. Here, in the piezoelectric element 560, when viewed along the Z-axis, the overlapping portion of the first electrode 561, the second electrode 562, and the piezoelectric layer 563 is the active portion, and the portion other than the active portion is the passive portion.

[0054] like Figure 4 As shown, a first wiring 110 is electrically connected to the first electrode 561, and a drive signal Com is supplied via the first wiring 110. The first wiring 110 is a lead wiring independently provided for each piezoelectric element 560, and is electrically connected to the first electrode 561 of the corresponding piezoelectric element 560. On the other hand, a second wiring 120 is electrically connected to the second electrode 562, and a fixed potential is supplied via the second wiring 120. The second wiring 120 is a common wiring provided for multiple piezoelectric elements 560, and is electrically connected to the second electrode 562.

[0055] exist Figure 4In the example shown, the first wiring 110 is connected to the first electrode 561 and extends from the first electrode 561 toward the wiring substrate 590 for each piezoelectric element 560. On the other hand, the second wiring 120 extends from the second electrode 562 toward the wiring substrate 590 at both ends in the Y1 and Y2 directions to the vibrating plate 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 predetermined intervals in the X1 direction. This second wiring 120 also functions as a counterweight for suppressing the vibration of the vibrating plate 550.

[0056] The constituent materials of the first wiring 110 and the second wiring 120 are not particularly limited, and 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 preferred as the constituent material of the first wiring 110 and the second wiring 120. Here, the first wiring 110 and the second wiring 120 are preferably constructed by laminating a layer made of gold as the surface layer on a layer made of nickel, chromium, or the like.

[0057] The first electrode 561 is disposed on the vibrating plate 550 and is an independent electrode arranged separately for each piezoelectric element 560. A drive signal Com is supplied to the first electrode 561. The second electrode 562 is disposed on the piezoelectric layer 563 and is a strip-shaped common electrode extending continuously in the Y-axis direction across multiple piezoelectric elements 560. For example, a fixed potential is supplied to the second electrode 562.

[0058] The materials that constitute the first electrode 561 and the second electrode 562 respectively include, for example, metal materials such as platinum (Pt), aluminum (Al), iridium (Ir), nickel (Ni), gold (Au), and copper (Cu). One of them can be used alone, or two or more can be combined in an alloy or layered manner.

[0059] When the first electrode 561 contains Ir, as described later, the diffusion of the components contained in the piezoelectric layer 563 can be suppressed. As a result, changes in the composition of the piezoelectric layer 563 can be suppressed.

[0060] exist Figure 5 and Figure 6In the example shown, an adhesive layer 561b is disposed between the diaphragm 550 and the first electrode 561. The adhesive layer 140 is a layer used to improve the adhesion between the first electrode 561 and the diaphragm 550, and is made of a metal such as titanium. It should be noted that at least a portion of the adhesive layer 140 can also be considered as part of the first electrode 561 or the diaphragm 550. In addition, for some reason, sometimes a layer made of titanium is placed between the first electrode 561 and the diaphragm 550.

[0061] A piezoelectric layer 563 is disposed on the first electrode 561 and is made of a piezoelectric material. Preferably, a composite oxide having a perovskite structure represented by the general formula ABO3 is used as this 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). Furthermore, the composite oxide is not limited to the aforementioned lead-containing compounds; it can also be a lead-free compound, such as sodium potassium niobate ((K,Na)NbO3, abbreviated as "KNN"), bismuth ferrite ((BiFeO3, abbreviated as "BFO"), lithium sodium potassium niobate ((K,Na,Li)(NbO3)), lithium sodium potassium niobate ((K,Na,Li)(Nb,Ta)O3), and bismuth manganate (BiMnO3, abbreviated as "BM"). Thus, when the piezoelectric layer 563 contains K, Na, and Nb, the piezoelectric layer 563 can be constructed from a lead-free material.

[0062] exist Figure 4 In the example shown, the piezoelectric layer 563 is a strip extending continuously along the Y-axis across multiple piezoelectric elements 560. Here, in the piezoelectric layer 563, a cutout G extending along the X-axis is provided in a region corresponding to the gap between adjacent pressure chambers C1 when viewed from above. It should be noted that the piezoelectric layer 563 can also be provided independently for each piezoelectric element 560. Additionally, the cutout G can also be a bottomed groove.

[0063] like Figure 6As shown, 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 in the piezoelectric layer 563 is a region 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 in the piezoelectric layer 563 is a region whose range along the Y-axis is the same as that of the first electrode 561. Furthermore, the third region A3 is a region of the piezoelectric layer 563 located between the first region A1 and the second region A2 in the Y1 or Y2 direction.

[0064] exist Figure 6 In the example shown, when viewed in a section orthogonal to the X-axis, the first region A1 is superimposed on a region F1 on the upper surface of the vibrating plate 550 that is flat along the Y1 or Y2 direction. Region F1 can also be described as a flat region on the upper surface of the vibrating plate 550 along an imaginary plane orthogonal to the Z-axis. On the other hand, when viewed in a section orthogonal to the X-axis, the second region A2 is superimposed on a region F2 on the upper surface of the first electrode 561 that is flat along the Y1 or Y2 direction. Region F2 can also be described as a flat region on the upper surface of the first electrode 561 along an imaginary plane orthogonal to the Z-axis. When viewed in a section orthogonal to the X-axis, the third region A3 is superimposed on a region F3 on the upper surface of the first electrode 561 that is inclined relative to the Y1 or Y2 direction. Region F3 can also be described as a flat region on the upper surface of the first electrode 561 that is inclined about the X-axis relative to an imaginary plane orthogonal to the Z-axis.

[0065] The tilt angle of region F3 relative to the imaginary plane orthogonal to the Z-axis is not particularly limited and can be arbitrary, as long as it is greater than 0° and less than 90°. In addition, the tilt of region F3 relative to the imaginary plane orthogonal to the Z-axis can be formed, for example, by adjusting the etching speed when patterning the first electrode 561 by etching or the use of a grayscale mask.

[0066] The seed layer 130 is located between the piezoelectric layer 563 and the vibrating plate 550, and is used to control the orientation of the piezoelectric layer 563. The seed layer 130 is in contact with the first electrode 561, the vibrating plate 550, and the piezoelectric layer 563, and has a crystal structure that serves as a seed crystal for the piezoelectric layer 563. This improves the orientation of the piezoelectric layer 563. Consequently, it increases the displacement force of the piezoelectric element 560. Therefore, it improves the ejection performance of the liquid ejector head 50.

[0067] The material constituting the seed layer 130 can be any material as long as it has the function of controlling the orientation of the piezoelectric layer 563, but it is preferred to contain titanium (Ti), and more preferably to contain bismuth (Bi), iron (Fe), titanium (Ti), and lead (Pb). The material containing bismuth (Bi), iron (Fe), titanium (Ti), and lead (Pb) is a composite oxide having a perovskite structure containing Bi and Pb at the A site and Fe and Ti at the B site, which can control the orientation of the piezoelectric layer 563.

[0068] Seed layer 130 includes a first seed layer 131 and a second seed layer 132. The first seed layer 131 is not configured in the first region A1, but in the second region A2. The second seed layer 132 is disposed above the first seed layer 131 and is configured across both the first region A1 and the second region A2.

[0069] The first seed layer 131 and the second seed layer 132 are each made of a material capable of controlling the orientation of the piezoelectric layer 563. Since the second seed layer 132 is disposed 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 passive portions. Therefore, damage such as cracks caused by differences in the orientation of the piezoelectric layer 563 between the active and passive portions can be reduced.

[0070] Furthermore, since the second seed layer 132 is disposed above the first seed layer 131, it is formed after the first seed layer 131 is formed, as will be described in detail later. Additionally, the first seed layer 131 can be heat-treated before the patterning of the first electrode 561 and the first seed layer 131. During this heat treatment, diffusible materials (especially Ti) in the layers such as the binder layer 140 directly below the first electrode 561 cannot diffuse laterally but diffuse in the thickness direction. Therefore, during this heat treatment, the material in the binder layer 140 and other layers does not concentrate and precipitate. Furthermore, the second seed layer 132 is heat-treated after the patterning of the first seed layer 131, but during this heat treatment, diffusible materials in the binder layer 140 and other layers have already diffused sufficiently. Therefore, during this heat treatment, the material in the binder layer 140 and other layers does not concentrate and precipitate at the end of the first electrode 561. Based on the above, the generation of damage such as cracks caused by local segregation of materials such as Ti in the binder layer 140 and other layers can also be reduced.

[0071] Here, when the first electrode 561 contains Ir, the Ir contained in the first electrode 561 is prone to diffusion due to heat treatment. Moreover, compared with combinations of other elements, Ir has a particularly significant effect on suppressing Ti diffusion. Therefore, in the case of Ti segregation, if the first electrode 561 contains Ir, the occurrence of local segregation of the material in layers such as the bonding layer 140 can be significantly reduced by using the first seed layer 131 and the second seed layer 132.

[0072] Furthermore, when the piezoelectric layer 563 contains K, Na, and Nb, since the piezoelectric layer 563 does not contain Ti, the affinity between the first electrode 561 and the piezoelectric layer 563 is reduced when the first electrode 561 contains Ti. Therefore, when Ti diffuses from the bonding layer 140 and other layers, Ti will not enter the piezoelectric layer 563 and will precipitate at the end of the first electrode 561. Thus, in this case, by using the first seed layer 131 and the second seed layer 132, the occurrence of local segregation of the material in the bonding layer 140 and other layers can be significantly reduced.

[0073] The first seed layer 131 is not disposed in the third region A3, while the second seed layer 132 is disposed in the third region A3. This improves the orientation of the third region A3. Here, if the first electrode 561 and the first seed layer 131 are formed through uniform patterning, the first seed layer 131 cannot be formed in region F3 of the first electrode 561. If the seed layer 130 is absent in region F3, the third region A3 between the first region A1 and the second region A2 becomes unoriented, resulting in a significant difference in orientation between these regions, which may lead to cracks. In contrast, by providing the second seed layer 132 on region F3, the orientation of the third region A3 can be improved. Consequently, by reducing the difference in orientation between these regions, the generation of cracks can be reduced.

[0074] When the thickness of the first seed layer 131 in the second region A2 is set as 'a', the thickness of the second seed layer 132 in the second region A2 is set as 'b', and the thickness of the second seed layer 132 in the first region A1 is set as 'c', it is preferable that a + b > c. In other words, it is preferable that the thickness (a + b) of the seed layer 130 in the second region A2 is greater than the thickness c of the seed layer 130 in the first region A1. This significantly improves the crystallinity of both the first region A1 and the second region A2 of the piezoelectric layer 563. Consequently, the generation of cracks in the piezoelectric layer 563 is significantly reduced.

[0075] Generally, the thicker the seed layer 130, the higher the crystallinity of the piezoelectric layer 563. However, for example, when KNN is used as the material for the piezoelectric layer 563, and ZrO is used... XWhen it is the material of the second layer 552 of the diaphragm 550, in the seed layer 130 above the second layer 552, if the thickness of the seed layer 130 is too thick, contrary to the normal situation, sometimes the crystallinity of the piezoelectric layer 563 may decrease. Therefore, if the seed layer 130 in the passive portion is formed with a thickness equal to or greater than the thickness of the seed layer 130 in the active portion, in the passive portion, since the piezoelectric layer 563 is directly laminated on the diaphragm 550, the crystallinity of the piezoelectric layer 563 becomes extremely low. As a result, sometimes cracks may occur in the same manner as when the piezoelectric layer 563 in the passive portion is non-oriented.

[0076] Therefore, it is preferable that the thicknesses a, b, and c satisfy the above relationship. Thus, since the decrease in the crystallinity of the piezoelectric layer 563 in the passive portion as described above can be reduced, the crystallinity of both the first region A1 and the second region A2 of the piezoelectric layer 563 can be improved well.

[0077] 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. Thus, it is possible to prevent the thickness of the seed layer 130 in the second region A2 from becoming more than the required thickness. As a result, the optimization of the orientation control of the piezoelectric layer 563 can be achieved in both the active portion and the passive portion. Here, since the first seed layer 131 exists in the active portion, the orientation control of the piezoelectric layer 563 can be performed through the first seed layer 131. On the other hand, since the first seed layer 131 does not exist in the passive portion, the orientation control of the piezoelectric layer 563 needs to be performed through 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, the optimization of the orientation control of the piezoelectric layer 563 can be achieved in both the active portion and the passive portion.

[0078] On the contrary, if the thickness c of the second seed layer 132 in the first region A1 is thinner than the thickness b of the second seed layer 132 in the second region A2, after the orientation control of the piezoelectric layer 563 is performed in both the active portion and the passive portion, the thickness of the seed layer 130 in the active portion becomes too thick. Therefore, there is a problem that the ejection characteristics decrease due to the increase in the resistance of the seed layer 130 in the active portion and the deterioration of the conductivity between the first electrode 561 and the piezoelectric layer 563.

[0079] When the thickness of the first seed layer 131 in the second region A2 is set to a, the thickness of the second seed layer 132 in the second region A2 is set to b, and the thickness of the second seed layer 132 in the first region A1 is set to c, it is preferable that b < a < c and a + b > c. Thus, b < c and a + b > c can be satisfied so that the difference between the thickness (a + b) and the thickness c is not too large.

[0080] At least a part of the first seed layer 131 and the second seed layer 132 are in contact with the first electrode 561 respectively. Such a first seed layer 131 and a second seed layer 132 are obtained by forming the second seed layer 132 after forming the first seed layer 131.

[0081] Preferably, the first seed layer 131 and the second seed layer 132 are made of the same material as each other. Thus, by improving the affinity between the first seed layer 131 and the second seed layer 132, the adhesion between the first seed layer 131 and the second seed layer 132 to each other can be improved. As a result, peeling between the first seed layer 131 and the second seed layer 132 can be reduced. In contrast, 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 become poor, and since the adhesion between the first seed layer 131 and the second seed layer 132 to each other becomes poor, peeling between the first seed layer 131 and the second seed layer 132 may occur.

[0082] Preferably, the first seed layer 131 and the second seed layer 132 each contain Ti. Thus, the first seed layer 131 and the second seed layer 132 capable of well controlling the orientation of the piezoelectric layer 563 can be realized.

[0083] Preferably, the first seed layer 131 and the second seed layer 132 each contain Bi, Fe, Ti, Pb. Thus, the seed layer 130 can be composed of a composite oxide having a perovskite structure, and thus the orientation of the piezoelectric layer 563 can be well improved.

[0084] When both the first seed layer 131 and the second seed layer 132 are provided, since the second seed layer 132 exists in both the first region A1 and the second region A2, the first region A1 and the second region A2 are respectively preferentially oriented to the (100) plane, and the orientation states of the first region A1 and the second region A2 are extremely 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 are preferentially oriented to the same crystal plane direction as each other.

[0085] In contrast, when only the first seed layer 131 is provided, since the first seed layer 131 exists only in the second region A2, the first region A1 is preferentially oriented to the (100) plane relative to the second region A2. In addition, in this case, the difference in orientation states between the first region A1 and the second region A2 is large.

[0086] 1-4: Manufacturing method of liquid nozzle Figure 7 and Figure 8 This is an explanatory diagram of the manufacturing method of the liquid ejector head 50 according to the embodiment. Figure 7 and Figure 8 As shown, the manufacturing method of the liquid ejector head 50 involves steps ST1 to ST7 sequentially. Each step will be described below.

[0087] In step ST1, a layer 561A formed from the material of the first electrode 561 is coated onto the vibrating plate 550. More specifically, step ST1 may be performed after the vibrating plate 550 is formed, and after uniformly forming an adhesive layer 140A by sputtering a metal such as titanium onto the second layer 552, layer 561A is uniformly formed by sputtering a metal such as platinum onto the adhesive layer 140A.

[0088] After step ST1, step ST2 coats layer 131A formed of the material of the first seed layer 131 onto layer 561A formed of the material of the first electrode 561. More specifically, step ST2 forms layer 131A as a precursor layer of the first seed layer 131 by coating layer 561A with a solution such as a MOD solution containing the precursor material of the first seed layer 131 using a spin coating method.

[0089] Following step ST2, step ST3 heat-treats layer 131A formed from the material of the first seed layer 131. More specifically, step ST3 involves drying and degreasing layer 131A, which serves as the precursor layer of the first seed layer 131, at approximately 350°C in an oven or similar environment, followed by heat treatment at approximately 750°C for about five minutes using RTA (rapid thermal annealing). This forms layer 131B, where the precursor constituting layer 131A is crystallized through firing. It should be noted that the heat treatment conditions are not limited to the above example and can be appropriately modified.

[0090] Following step ST3, step ST4 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 ST4 patterns layers 561A and 131B uniformly, for example, 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 bonding layer 140A is patterned to form the bonding layer 140.

[0091] Following step ST4, step ST5 involves coating the vibrating plate 550 and the first seed layer 131 (a layer formed from the material of the first seed layer 131) with a layer 132A formed from the material of the second seed layer 132. More specifically, step ST5 forms layer 132A as a precursor layer of the second seed layer 132 by coating the vibrating plate 550 and the first seed layer 131 with a solution such as a MOD solution containing the precursor material of the second seed layer 132 using a spin coating method.

[0092] Following step ST5, step ST6 heat-treats layer 132A formed from the material of the second seed layer 132. More specifically, step ST6 involves, for example, drying and degreasing layer 132A, which serves as the precursor layer of the second seed layer 132, at approximately 350°C using an oven or similar method, followed by heat treatment at approximately 750°C for about five minutes using an RTA (Radio-Tapered Acid) process. This forms a second seed layer 132, where the precursor constituting layer 132A is crystallized through firing. It should be noted that the heat treatment conditions are not limited to the above example and can be appropriately varied. Furthermore, the temperature and time conditions of the heat treatment in step ST6 can be the same as or different from the conditions of the heat treatment in step ST3.

[0093] Following step ST6, step ST7 involves coating a piezoelectric material onto the second seed layer 132 (a layer formed from the material of the second seed layer 132). More specifically, step ST7 involves, for example, forming a precursor layer 563 by coating a solution such as a MOD solution containing a precursor material of the piezoelectric material onto the second seed layer 132 using a spin coating method, drying and degreasing the precursor layer at approximately 350°C in an oven, or similarly, followed by heat treatment at approximately 750°C for approximately five minutes using an RTA method. This forms the piezoelectric layer 563. It should be noted that the coating and heat treatment of the piezoelectric material can be performed in multiple steps. Furthermore, the conditions for the heat treatment are not limited to the above example and can be appropriately varied.

[0094] Following step ST7 above, although not shown, the piezoelectric layer 563 is patterned using known processing techniques such as photolithography and etching. At this time, a portion of the second seed layer 132 is also removed through patterning so that the top-view shape of the second seed layer 132 matches the top-view shape of the piezoelectric layer 563. Thus, the piezoelectric element 560 is obtained. Then, the liquid ejector head 50 is obtained through appropriate known processes. It should be noted that the patterning of the piezoelectric layer 563 is performed, for example, after the pressure chamber C1 relative to the pressure chamber substrate 520 is formed.

[0095] In the above-described method for manufacturing the liquid ejector head 50, a heat treatment in step ST3 is performed before patterning in step ST4. During this heat treatment, diffusible materials such as Ti in the layers such as the binder layer 140A directly below layer 561A cannot diffuse laterally but diffuse in the thickness direction. Therefore, during this heat treatment, the material of the binder layer 140A and other layers does not precipitate out in a concentrated manner. Furthermore, after patterning in step ST4, a heat treatment for the second seed layer 132 is performed in step ST6, but during this heat treatment, the diffusible material in the binder layer 140 and other layers has already diffused sufficiently in step ST3. Therefore, during this heat treatment, the material of the binder layer 140 and other layers does not precipitate out in a concentrated manner at the end of the first electrode 561. Based on the above, the generation of cracks caused by local segregation of the material in the binder layer 140 and other layers can also be reduced.

[0096] The effects of the above manufacturing method will be explained below by comparing it with Comparative Examples 1 and 2.

[0097] (Comparative Example 1) Figure 9 This is an explanatory diagram illustrating the manufacturing method of the liquid ejector head 50X involved in Comparative Example 1. The liquid ejector head 50X is constructed in the same manner as the liquid ejector head 50, except that it has a seed layer 130X replacing the seed layer 130. The seed layer 130X is constructed in the same manner as the seed layer 130, except that the first seed layer 131 is omitted. That is, the seed layer 130X is composed only of the second seed layer 132.

[0098] like Figure 9 As shown, the manufacturing method of the liquid nozzle 50X involves sequentially performing steps ST2X to ST5X. Each step will be described below. It should be noted that, in the following descriptions, matters identical to those in the manufacturing method of the liquid nozzle 50 will be either followed or omitted as appropriate.

[0099] Following step ST1, step ST2X patterns the layer 561A formed from the material of the first electrode 561. This forms a first electrode 561 consisting of the patterned first electrode 561 and the bonding layer 140.

[0100] After step ST2X, step ST3X coats layer 132A, formed of the material of the second seed layer 132, onto the vibrating plate 550 and the first electrode 561.

[0101] After step ST3X, step ST4X heats the layer 132A formed from the material of the second seed layer 132. This forms a seed layer 130X, which is formed by crystallizing the precursor layer 132A through firing.

[0102] After step ST4X, step ST5X coats a piezoelectric material onto the seed layer 130X. This forms the piezoelectric layer 563.

[0103] In the above-described method for manufacturing the liquid ejector head 50X, during the heat treatment in step ST4X, materials such as Ti, which are diffusible in the materials of layers such as the sealing layer 140, diffuse into other layers. However, the first electrode 561 (especially the Ir and the like contained in the first electrode 561) has properties that make it difficult for Ti and the like to diffuse. Therefore, during the heat treatment in step ST4X, since the first electrode 561 is disposed on the upper side of the sealing layer 140, materials such as Ti do not easily diffuse onto the upper side of the sealing layer 140. However, since the patterning in step ST2X is performed before the heat treatment in step ST4X, there is no structure to inhibit Ti diffusion above the end of the first electrode 561 (especially the tapered portion of region X) during the heat treatment in step ST4X. Therefore, during the heat treatment in step ST4X, Ti and the like segregate near the end of the first electrode 561. If such localized segregation of Ti or the like occurs, oxides such as TiOx will form, causing the piezoelectric material formed at the end of the first electrode 561 to have a raised portion, which may cause cracks.

[0104] (Comparative Example 2) Figure 10 This is an explanatory diagram illustrating the manufacturing method of the liquid ejector head 50Y involved in Comparative Example 2. The liquid ejector head 50Y is constructed in the same manner as the liquid ejector head 50, except that it has a seed layer 130Y replacing the seed layer 130. The seed layer 130Y is constructed in the same manner as the seed layer 130, except that the second seed layer 132 is omitted. That is, the seed layer 130Y is composed only of the first seed layer 131.

[0105] like Figure 10 As shown, the manufacturing method of the liquid nozzle 50Y involves steps ST5Y and ST6Y sequentially. Each step will be described below. It should be noted that, in the following descriptions, matters identical to those in the manufacturing method of the liquid nozzle 50 will be either followed or omitted as appropriate.

[0106] Step ST5Y forms a patterned first electrode 561 by performing steps ST1 to ST4, and forms a seed layer 130Y as a patterned first seed layer 131.

[0107] Following step ST5Y, step ST6Y involves coating a piezoelectric material onto the vibrating plate 550 and the seed layer 130Y. This forms a piezoelectric layer 563.

[0108] In the above-described method for manufacturing the liquid ejector head 50Y, the first electrode 561 and the seed layer 130Y are formed by performing steps ST1 to ST4. Therefore, similar to the method for manufacturing the liquid ejector head 50, the segregation of materials such as Ti in the layers such as the sealing layer 140A is eliminated. The mechanism is considered to be the same as described in the above-described method for manufacturing the liquid ejector head 50. That is, since the patterning of layer 561A is not performed at the time of the heat treatment in step ST3, layer 561A is formed over the entire area above the material such as Ti to be diffused, and there is no escape channel for the material as in the conical portion of region F3 in Comparative Example 1. Therefore, even if layer 131A is heat-treated in step ST3, the material such as Ti will not segregate to a specific area as in Comparative Example 1, and most of it will escape to the vibrating plate 550 (more specifically, from ZrO). X The second layer 552 is composed of materials such as Ti. This can suppress the segregation of Ti and other materials at the end of the first electrode 561.

[0109] However, in Comparative Example 2, the seed layer 130Y was not provided in the passive section. Therefore, the orientation of the piezoelectric layer 563 differs greatly between the active and passive sections, resulting in cracks at its boundaries.

[0110] In contrast, Figure 7 and Figure 8 In the manufacturing method of the liquid ejector head 50 shown, the second seed layer 132 is disposed across both the active and passive portions, thus enabling control over the orientation of the piezoelectric layer 563 in both the active and passive portions. This reduces the generation of cracks caused by differences in the orientation of the piezoelectric layer 563 between the active and passive portions.

[0111] It should be noted that in Comparative Example 1, a heat treatment was also considered between process ST1 and process ST2X solely to ensure sufficient diffusion of the Ti and other materials in the bonding layer 140 and other layers. However, in this case, since the heat treatment is performed with layer 561A exposed, the surface of layer 561A becomes rough, resulting in a decrease in the orientation of the piezoelectric layer 563 due to a reduction in the characteristics of the seed layer 130X. In contrast, in process ST3, the heat treatment is performed with the surface of layer 561A protected by layer 131A, thus avoiding this problem, and the Ti and other materials in the bonding layer 140 and other layers diffuse sufficiently without segregation.

[0112] 2: Variation Example The methods illustrated above can be modified in various ways. The following examples illustrate specific modifications applicable to the methods described above. Any aspect selected from the following examples can be appropriately combined without contradiction.

[0113] 2-1: Variation Example 1 In the above embodiments, the second electrode 562 is exemplified as a common electrode, but it is not limited to this aspect. The second electrode 562 may also be an independent electrode for each piezoelectric element 650. In this case, the first electrode 561 may also be a common electrode shared by multiple piezoelectric elements 560. However, even when the first electrode 561 is set as a common electrode and the second electrode 562 is set as an independent electrode, the piezoelectric layer 563 also includes a region that does not overlap with the first electrode 561.

[0114] 2-2: Variation Example 2 In the above embodiments, a serial liquid ejection device 100 is illustrated in which the conveyor body 41 equipped with the liquid ejection head 50 reciprocates, but the present invention is also applicable to a row-type liquid ejection device in which multiple nozzles N are distributed over the entire width of the recording medium M.

[0115] 2-3: Variation Example 3 The liquid ejection apparatus 100 illustrated in the above description can be used not only in printing equipment but also in various other equipment such as fax machines and copiers; the application of this disclosure is not particularly limited. Originally, the application of the liquid ejection apparatus was not limited to printing. For example, a liquid ejection apparatus for ejecting pigment solutions is used as a manufacturing apparatus for color filters in display devices such as liquid crystal display panels. Furthermore, a liquid ejection apparatus for ejecting conductive material solutions is used as a manufacturing apparatus for wiring and electrodes in wiring substrates. Additionally, a liquid ejection apparatus for ejecting solutions of organic substances related to living organisms is used, for example, as a manufacturing apparatus for biochips.

Claims

1. A liquid ejection head, characterized by, The liquid ejection head has: a pressure chamber substrate having a plurality of pressure chambers arranged in a first direction; a vibration plate disposed on the pressure chamber substrate; a first electrode disposed on the vibration plate; a piezoelectric layer disposed on the first electrode; a second electrode disposed on the piezoelectric layer; and a seed layer between the piezoelectric layer and the vibration plate for controlling orientation of the piezoelectric layer, the piezoelectric layer has: a first region not overlapping the first electrode in the first direction; and a second region overlapping the first electrode in the first direction, the seed layer includes: a first seed layer not disposed in the first region but disposed in the second region; and a second seed layer disposed on the first seed layer and disposed across both the first region and the second region.

2. The liquid ejection head according to claim 1, wherein when a thickness of the first seed layer in the second region is set as a, a thickness of the second seed layer in the second region is set as b, a thickness of the second seed layer in the first region is set as c, a + b > c is satisfied.

3. The liquid ejection head according to claim 1, wherein when a thickness of the second seed layer in the second region is set as b, a thickness of the second seed layer in the first region is set as c, b < c is satisfied.

4. The liquid ejection head according to claim 1, wherein when a thickness of the first seed layer in the second region is set as a, a thickness of the second seed layer in the second region is set as b, a thickness of the second seed layer in the first region is set as c, b < a < c and a + b > c are satisfied.

5. The liquid ejection head according to claim 1, wherein at least a part of each of the first seed layer and the second seed layer is in contact with the first electrode.

6. The liquid ejection head according to claim 1, wherein the first seed layer and the second seed layer are composed of the same material as each other.

7. The liquid ejection head according to claim 1, wherein each of the first seed layer and the second seed layer contains Ti.

8. The liquid ejection head according to claim 1, wherein each of the first seed layer and the second seed layer contains Bi, Fe, Ti, Pb.

9. The liquid ejection head according to claim 1, wherein the first electrode contains Ir.

10. The liquid ejection head according to claim 1, wherein the piezoelectric layer contains K, Na, Nb.

11. The liquid ejection head according to claim 1, wherein the first region is a region laminated on a region flat in the first direction in an upper surface of the vibration plate, the second region is a region laminated on a region flat in the first direction in an upper surface of the first electrode.

12. The liquid ejection head according to claim 11, wherein ​ ​ ​ The piezoelectric layer further includes a third region between the first region and the second region in the first direction, The third region is layered over a region inclined with respect to the first direction in an upper surface of the first electrode.

13. The liquid ejection head according to claim 12, wherein The first seed layer is not disposed in the third region, The second seed layer is also disposed in the third region.

14. A liquid ejection device, comprising: having: the liquid ejection head according to any one of claims 1 to 13; and a control section that controls an ejection operation from the liquid ejection head.

15. A method of manufacturing a liquid ejection head, the method comprising: the liquid ejection head having: a pressure chamber substrate having a plurality of pressure chambers arranged in a first direction; and a vibration plate disposed on the pressure chamber substrate, in the method of manufacturing the liquid ejection head, the following steps are performed in order: applying a layer formed of a material of a first electrode over the vibration plate; applying a layer formed of a material of a first seed layer over the layer formed of the material of the first electrode; performing a heat treatment on the layer formed of the material of the first seed layer; performing patterning on the layer formed of the material of the first electrode and the layer formed of the material of the first seed layer; applying a layer formed of a material of a second seed layer over the vibration plate and the layer formed of the material of the first seed layer; performing a heat treatment on the layer formed of the material of the second seed layer; and applying a piezoelectric body over the layer formed of the material of the second seed layer. ​

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