Piezoelectric element, liquid dispensing head, and liquid dispensing device

Abstract

To provide a piezoelectric element that can improve the insulating properties of the piezoelectric layer. [Solution] A piezoelectric element comprising a substrate, a first electrode provided on the substrate, a piezoelectric layer provided on the first electrode and containing potassium, sodium, and niobium, and a second electrode provided on the piezoelectric layer, wherein the piezoelectric layer has a first layer provided on the first electrode and a second layer provided on the first layer, and the piezoelectric layer has a first region including a first interface between the first layer and the second layer and a second region located within the first layer without including the first interface, and the molar ratio of potassium to sodium in the first region is greater than the molar ratio in the second region.

Description

[Technical Field]

[0001] The present invention relates to a piezoelectric element, a liquid dispensing head, and a liquid dispensing device. [Background technology]

[0002] Piezoelectric elements used in inkjet printer liquid ejection heads, for example, are constructed by sandwiching a piezoelectric layer made of a piezoelectric material with electromechanical conversion capabilities between two electrodes.

[0003] For example, Patent Document 1 describes a piezoelectric laminate comprising a piezoelectric film made of potassium sodium niobate (KNN) formed by sputtering. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-30638 [Overview of the project] [Problems that the invention aims to solve]

[0005] Piezoelectric films using KNN as described above are known to be prone to leakage current. Therefore, improving the insulating properties of the piezoelectric film is desirable to reduce leakage current. [Means for solving the problem]

[0006] One embodiment of the piezoelectric element according to the present invention is: circuit board and A first electrode provided on the substrate, A piezoelectric layer comprising potassium, sodium, and niobium is provided on the first electrode, A second electrode provided on the piezoelectric layer, Includes, The piezoelectric layer is A first layer provided on the first electrode, A second layer provided on the first layer, and the piezoelectric layer has a first region including a first interface between the first layer and the second layer, and a second region located within the first layer without including the first interface. And a molar ratio of potassium to sodium in the first region is larger than the molar ratio in the second region.

[0007] One aspect of the liquid ejection head according to the present invention includes the piezoelectric element.

[0008] One aspect of the liquid ejection device according to the present invention includes the liquid ejection head.

Brief Description of the Drawings

[0009] [Figure 1] A cross-sectional view schematically showing the piezoelectric element according to the present embodiment. [Figure 2] A cross-sectional view schematically showing the piezoelectric element according to the present embodiment. [Figure 3] An exploded perspective view schematically showing the liquid ejection head according to the present embodiment. [Figure 4] A plan view schematically showing the liquid ejection head according to the present embodiment. [Figure 5] A cross-sectional view schematically showing the liquid ejection head according to the present embodiment. [Figure 6] A perspective view schematically showing the liquid ejection device according to the present embodiment. [Figure 7] A graph showing the results of SIMS analysis of Example 1 and Example 2. [Figure 8] A graph showing the results of SIMS analysis of Comparative Example 1. [Figure 9] A graph showing the results of SIMS analysis of Example 3.

Modes for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention described in the claims. Also, not all of the configurations described below are essential constituent elements of the present invention.

[0011] 1. Piezoelectric Element 1.1. Configuration First, the piezoelectric element according to this embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing the piezoelectric element 100 according to this embodiment.

[0012] As shown in FIG. 1, the piezoelectric element 100 includes, for example, a substrate 10, a first electrode 20, an orientation control layer 30, a piezoelectric layer 40, and a second electrode 50.

[0013] The substrate 10 is, for example, a flat plate formed of a semiconductor, an insulator, or the like. The substrate 10 may be a single layer or a laminate in which a plurality of layers are laminated. The substrate 10 is not limited in its internal structure as long as its upper surface has a planar shape, and may have a structure in which a space or the like is formed inside.

[0014] The substrate 10 may have a diaphragm that is deformed by the operation of the piezoelectric layer 40. The diaphragm is, for example, a silicon oxide layer, a zirconium oxide layer, or a laminate in which a zirconium oxide layer is provided on a silicon oxide layer.

[0015] In the description according to the present invention, the term "above" is used, for example, as "forming another specific thing (hereinafter referred to as "B") "above" a specific thing (hereinafter referred to as "A") ". In the description according to the present invention, in such a case as this example, the term "above" is used as including both the case of directly forming B on A and the case of forming B on A via another thing.

[0016] The first electrode 20 is provided on the substrate 10. The first electrode 20 is provided between the substrate 10 and the orientation control layer 30. The shape of the first electrode 20 is layered. The thickness of the first electrode 20 is, for example, 5 nm to 300 nm, preferably 50 nm to 200 nm.

[0017] The first electrode 20 is, for example, a titanium layer, a platinum layer, or an iridium layer. The first electrode 20 may be laminated in the order of titanium layer, platinum layer, and iridium layer from the substrate 10 side. The titanium layer improves the adhesion between the substrate 10 and the platinum layer, for example. The first electrode 20 may have a titanium oxide layer instead of a titanium layer. The first electrode 20 is one electrode for applying a voltage to the piezoelectric layer 40. The first electrode 20 is, for example, a lower electrode provided on the underside of the piezoelectric layer 40.

[0018] The orientation control layer 30 is provided on the first electrode 20. The orientation control layer 30 is provided between the first electrode 20 and the piezoelectric layer 40. In the illustrated example, the orientation control layer 30 is further provided on the substrate 10. The thickness of the orientation control layer 30 is, for example, 5 nm to 30 nm, preferably 10 nm to 25 nm. The orientation control layer 30 includes, for example, a composite oxide with a perovskite structure containing bismuth (Bi), iron (Fe), titanium (Ti), and lead (Pb). The orientation control layer 30 is, for example, a bismuth lead iron titanate ((Bi,Pb)(Fe,Ti)O3:BFTP) layer. The orientation control layer 30 may also be a BFTP layer with additives added. The orientation control layer 30 controls the orientation of the piezoelectric layer 40. Specifically, the orientation control layer 30 orients the piezoelectric layer 40 to the (100) plane.

[0019] The piezoelectric layer 40 is provided on the orientation control layer 30. The piezoelectric layer 40 is provided on the first electrode 20 via the orientation control layer 30. The piezoelectric layer 40 is provided between the orientation control layer 30 and the second electrode 50. The thickness of the piezoelectric layer 40 is, for example, 100 nm to 3000 nm, preferably 500 nm to 2000 nm. The piezoelectric layer 40 deforms when a voltage is applied between the first electrode 20 and the second electrode 50.

[0020] The piezoelectric layer 40 contains a composite oxide with a perovskite structure containing potassium (K), sodium (Na), and niobium (Nb). The piezoelectric layer 40 is a potassium sodium niobate ((K,Na)NbO3:KNN) layer. The composition of the perovskite structure of the piezoelectric layer 40 may be a chemotherapeutic composition or a composition different from a chemotherapeutic composition. This is also true for the orientation control layer 30. The piezoelectric layer 40 may be a KNN layer with additives added. Examples of additives include lithium (Li), manganese (Mn), and copper (Cu). Such additives can reduce the leakage current of the piezoelectric layer 40.

[0021] The piezoelectric layer 40 has a plurality of crystalline layers 42. The piezoelectric layer 40 is composed of, for example, a plurality of crystalline layers 42. The number of crystalline layers 42 is, for example, 2 to 20, preferably 3 to 15. In the illustrated example, there are 8 crystalline layers 42. The thickness of the crystalline layers 42 is, for example, 10 nm to 300 nm, preferably 50 nm to 200 nm. In the plurality of crystalline layers 42, the thicknesses of the crystalline layers 42 may be the same or different.

[0022] Of the multiple crystal layers 42 of the piezoelectric layer 40, the first crystal layer 42a is provided on the orientation control layer 30, the second crystal layer 42b is provided on the first crystal layer 42a, and the third crystal layer 42c is provided on the second crystal layer 42b. The first crystal layer 42a is provided on the first electrode 20 via the orientation control layer 30. The first crystal layer 42a is provided between the orientation control layer 30 and the second crystal layer 42b. The first crystal layer 42a is in contact with the orientation control layer 30. The second crystal layer 42b is provided between the first crystal layer 42a and the third crystal layer 42c. The second crystal layer 42b is in contact with the first crystal layer 42a. The third crystal layer 42c is in contact with the second crystal layer 42b.

[0023] Here, Figure 2 is a schematic cross-sectional view of the piezoelectric element 100, and is an enlarged view of the vicinity of the first crystal layer 42a in Figure 1.

[0024] As shown in Figure 2, the piezoelectric layer 40 has, for example, a plurality of K-rich regions 44 and a plurality of Na-rich regions 46. The K-rich regions 44 include the interfaces of adjacent crystal layers 42. The Na-rich regions 46 do not include the interfaces of adjacent crystal layers 42. In the illustrated example, the Na-rich regions 46 include the midpoints of the interfaces of adjacent crystal layers 42 in the thickness direction of the piezoelectric layer 40. The K-rich regions 44 and Na-rich regions 46 are arranged alternately, for example, in the thickness direction of the piezoelectric layer 40. Note that "thickness direction of the piezoelectric layer 40" refers to a plurality of interfaces This refers to the stacking direction of the crystal layer 42 and the depth direction of the piezoelectric layer 40.

[0025] In the K-rich region 44, the molar ratio of potassium to sodium (hereinafter also referred to as the "K / Na molar ratio") is greater than the K / Na molar ratio in the Na-rich region 46. In the K-rich region 44, for example, the atomic concentration (at%) of potassium is greater than the atomic concentration (at%) of sodium. In the K-rich region 44, for example, the number of moles of potassium is greater than the number of moles of sodium. In the Na-rich region 46, for example, the atomic concentration (at%) of potassium is less than the atomic concentration (at%) of sodium. The K / Na molar ratio and the atomic concentrations (at%) of each element are measured, for example, by SIMS (Secondary Ion Mass Spectrometry) analysis and EDS (Energy Dispersive X-ray Spectroscopy) analysis.

[0026] The first K-rich region 44a among the multiple K-rich regions 44 includes the first interface 43a between the first crystal layer 42a and the second crystal layer 42b. The first Na-rich region 46a among the multiple Na-rich regions 46 is located within the first crystal layer 42a without including the first interface 43a between the first crystal layer 42a and the second crystal layer 42b. The first Na-rich region 46a is located between the orientation control layer 30 and the first K-rich region 44a. In the illustrated example, the first Na-rich region 46a is in contact with the orientation control layer 30.

[0027] Of the multiple K-rich regions 44, the second K-rich region 44b includes the second interface 43b between the second crystal layer 42b and the third crystal layer 42c. Of the multiple Na-rich regions 46, the second Na-rich region 46b is located within the second crystal layer 42b without including the second interface 43b between the second crystal layer 42b and the third crystal layer 42c.

[0028] The atomic concentration (at%) of niobium in the K-rich region 44 is greater than, for example, the atomic concentration (at%) of niobium in the Na-rich region 46. The difference between the atomic concentration (at%) of niobium in the K-rich region 44 and the atomic concentration (at%) of niobium in the Na-rich region 46 is smaller than, for example, the difference between the atomic concentration (at%) of potassium in the K-rich region 44 and the atomic concentration (at%) of potassium in the Na-rich region 46. Furthermore, the difference between the atomic concentration (at%) of niobium in the K-rich region 44 and the atomic concentration (at%) of niobium in the Na-rich region 46 is smaller than, for example, the difference between the atomic concentration (at%) of sodium in the K-rich region 44 and the atomic concentration (at%) of sodium in the Na-rich region 46.

[0029] The atomic concentration (at%) of manganese in the K-rich region 44 is greater than, for example, the atomic concentration (at%) of manganese in the Na-rich region 46. The atomic concentration (at%) of copper in the K-rich region 44 is greater than, for example, the atomic concentration (at%) of copper in the Na-rich region 46. The atomic concentration (at%) of lithium in the Na-rich region 46 is greater than, for example, the atomic concentration (at%) of lithium in the K-rich region 44.

[0030] As shown in Figure 1, the second electrode 50 is provided on the piezoelectric layer 40. In the illustrated example, the second electrode 50 covers the top and side surfaces of the piezoelectric layer 40 and is provided on the substrate 10. The shape of the second electrode 50 is layered. The thickness of the second electrode 50 is, for example, 5 nm to 300 nm, preferably 30 nm to 200 nm.

[0031] The second electrode 50 is, for example, a platinum layer, a titanium layer, an iridium layer, or a laminate thereof. The second electrode 50 is the other electrode for applying a voltage to the piezoelectric layer 40. The second electrode 50 is, for example, an upper electrode provided on the upper side of the piezoelectric layer 40.

[0032] 1.2. Effects In the piezoelectric element 100, there is a substrate 10, a first electrode 20 provided on the substrate 10, and the first electrode The electrode includes a piezoelectric layer 40 provided on the electrode 20 and containing potassium, sodium, and niobium, and a second electrode 50 provided on the piezoelectric layer 40. The piezoelectric layer 40 has a first crystalline layer 42a as a first layer provided on the first electrode 20, and a second crystalline layer 42b as a second layer provided on the first crystalline layer 42a. The piezoelectric layer 40 has a first K-rich region 44a as a first region including a first interface 43a between the first crystalline layer 42a and the second crystalline layer 42b, and a first Na-rich region 46a as a second region located within the first crystalline layer 42a without including the first interface 43a. The K / Na molar ratio in the first K-rich region 44a is greater than the K / Na molar ratio in the first Na-rich region 46a.

[0033] Therefore, in the piezoelectric element 100, since the first Na-rich region 46a is located on the first electrode 20 side, the first crystal layer 42a can be grown using sodium niobate, which crystallizes easily from the first electrode 20 side, as a nucleus, in the order of sodium niobate and potassium niobate. Since sodium niobate (NaNbO3) has a crystallization temperature about 100°C lower than potassium niobate (KNbO3), growing the first crystal layer 42a using sodium niobate as a nucleus can promote crystal growth of the piezoelectric layer 40. Furthermore, in the piezoelectric element 100, the insulating properties of the piezoelectric layer 40 can be improved in the highly insulating first K-rich region 44a, thereby reducing leakage current.

[0034] In the piezoelectric element 100, the atomic concentration of potassium (at%) is greater than that of sodium (at%) in the first K-rich region 44a, and the atomic concentration of potassium (at%) is less than that of sodium (at%) in the first Na-rich region 46a. Therefore, in the piezoelectric element 100, crystal growth of the piezoelectric layer 40 can be promoted and the insulating properties of the piezoelectric layer 40 can be improved.

[0035] In the piezoelectric element 100, the piezoelectric layer 40 has a third crystal layer 42c as a third layer provided on the second crystal layer 42b. The piezoelectric layer 40 has a second K-rich region 44b as a third region including the second interface 43b between the second crystal layer 42b and the third crystal layer 42c, and a second Na-rich region 46b as a fourth region located within the second crystal layer 42b without including the second interface 43b. The K / Na molar ratio in the second K-rich region 44b is greater than the K / Na molar ratio in the second Na-rich region 46b. Therefore, in the piezoelectric element 100, the insulating properties of the piezoelectric layer 40 can be further improved by the second K-rich region 44b.

[0036] In the piezoelectric element 100, the atomic concentration (at%) of niobium in the first K-rich region 44a is greater than the atomic concentration (at%) of niobium in the first Na-rich region 46a. Therefore, the piezoelectric element 100 can reduce niobium defects in the first K-rich region 44a. This effectively improves the insulating properties in the first K-rich region 44a.

[0037] In the piezoelectric element 100, the difference between the atomic concentration (at%) of niobium in the first K-rich region 44a and the atomic concentration (at%) of niobium in the first Na-rich region 46a is smaller than the difference between the atomic concentration (at%) of potassium in the first K-rich region 44a and the atomic concentration (at%) of potassium in the first Na-rich region 46a, and the difference between the atomic concentration (at%) of sodium in the first K-rich region 44a and the atomic concentration (at%) of sodium in the first Na-rich region 46a. Therefore, in the piezoelectric element 100, the compositional gradient of niobium in the thickness direction of the piezoelectric layer 40 is flatter compared to potassium and sodium, and niobium defects can be reduced throughout the piezoelectric layer 40. This effectively improves the insulating properties of the piezoelectric layer 40.

[0038] In piezoelectric element 100, the piezoelectric layer 40 contains manganese, and the atomic concentration (at%) of manganese in the first K-rich region 44a is greater than the atomic concentration (at%) of manganese in the first Na-rich region 46a. Therefore, in piezoelectric element 100, the first K-rich region 44 The difference between the lattice constant of region a and the lattice constant of the first Na-rich region 46a can be reduced, thereby improving lattice matching. This reduces the stress generated in the piezoelectric layer 40. As a result, the possibility of cracks occurring in the piezoelectric layer 40 can be reduced.

[0039] In the piezoelectric element 100, the piezoelectric layer 40 contains copper, and the atomic concentration (at%) of copper in the first K-rich region 44a is greater than the atomic concentration (at%) of copper in the first Na-rich region 46a. Therefore, in the piezoelectric element 100, the difference between the lattice constant of the first K-rich region 44a and the lattice constant of the first Na-rich region 46a can be reduced, improving lattice matching. This reduces the stress generated in the piezoelectric layer 40. As a result, the possibility of cracks occurring in the piezoelectric layer 40 can be reduced.

[0040] In the piezoelectric element 100, the piezoelectric layer 40 contains lithium, and the atomic concentration (at%) of lithium in the first Na-rich region 46a is greater than the atomic concentration (at%) of lithium in the first K-rich region 44a. Therefore, in the piezoelectric element 100, some of the sodium in the first Na-rich region 46a is more easily replaced by lithium, which promotes crystal growth in the piezoelectric layer 40.

[0041] In the piezoelectric element 100, an orientation control layer 30 containing bismuth, iron, titanium, and lead is provided between the first electrode 20 and the piezoelectric layer 40, and the first Na-rich region 46a is located between the orientation control layer 30 and the first K-rich region 44a. Therefore, in the piezoelectric element 100, the lattice matching between the piezoelectric layer 40 and the orientation control layer 30 can be improved. This reduces the stress generated in the piezoelectric layer 40. As a result, the possibility of cracks occurring in the piezoelectric layer 40 can be reduced.

[0042] 2. Method for manufacturing piezoelectric elements Next, the manufacturing method of the piezoelectric element 100 according to this embodiment will be described with reference to the drawings.

[0043] As shown in Figure 1, the substrate 10 is prepared. Specifically, a silicon oxide layer is formed by thermal oxidation of a silicon substrate. Next, a zirconium layer is formed on the silicon oxide layer by sputtering or the like, and a zirconium oxide layer is formed by thermal oxidation of the zirconium layer. Through these steps, the substrate 10 can be prepared.

[0044] Next, a first electrode 20 is formed on the substrate 10. The first electrode 20 is formed, for example, by sputtering or vacuum deposition. Then, the first electrode 20 is patterned, for example, by photolithography and etching.

[0045] Next, an orientation control layer 30 is formed on the first electrode 20 and the substrate 10. The orientation control layer 30 is formed by a CSD (Chemical Solution Deposition) method such as the sol-gel method or MOD (Metal Organic Deposition).

[0046] Specifically, first, a precursor solution is prepared by dissolving or dispersing a bismuth-containing metal complex, an iron-containing metal complex, a titanium-containing metal complex, and a lead-containing metal complex in an organic solvent. Next, the precursor solution is applied to the first electrode 20 and the substrate 10 by spin coating to form a precursor layer. Then, the precursor layer is dried for a certain period of time by heating, for example, 130°C to 250°C, and further degreased by heating, for example, 300°C to 450°C and holding for a certain period of time. Next, the degreased precursor layer is crystallized by firing, for example, 550°C to 800°C. Through the above steps, an orientation-controlled layer 30 consisting of a BFTP layer can be formed.

[0047] Next, a piezoelectric layer 40 is formed on the orientation control layer 30. The piezoelectric layer 40 is formed, for example, by the CSD method. Below, we will describe the case in which a KNN layer containing lithium, manganese, and copper as additives is formed as the piezoelectric layer 40.

[0048] First, a precursor solution is prepared by dissolving or dispersing a metal complex containing potassium, a metal complex containing sodium, a metal complex containing niobium, a metal complex containing lithium, a metal complex containing manganese, and a metal complex containing copper in an organic solvent.

[0049] Examples of metal complexes containing potassium include potassium 2-ethylhexanoate and potassium acetate. Examples of metal complexes containing sodium include sodium 2-ethylhexanoate and sodium acetate. Sodium 2-ethylhexanoate is stable and therefore easy to use as a raw material. Furthermore, sodium 2-ethylhexanoate has a low melting point, and its oxide also has a low melting point, making it easy to use as a crystal nucleus. Examples of metal complexes containing niobium include niobium 2-ethylhexanoate. Examples of metal complexes containing lithium include lithium 2-ethylhexanoate. Examples of metal complexes containing manganese include manganese 2-ethylhexanoate. Examples of metal complexes containing copper include copper 2-ethylhexanoate. Examples of solvents include 2-ethylhexanoic acid, decane, or mixed solvents thereof.

[0050] In the precursor solution, the molar ratio of potassium to sodium is, for example, 0.7 to 1.3, preferably 0.8 to 1.2, and more preferably 0.9 to 1.1.

[0051] Next, the prepared precursor solution is applied onto the orientation control layer 30 using a spin coating method or the like to form a precursor layer. Next, the precursor layer is heated to, for example, 150°C to 280°C and dried for a certain period of time. Furthermore, the dried precursor layer is degreased by heating to, for example, 300°C to 450°C and holding for a certain period of time. Next, the degreased precursor layer is held at a first temperature of 400°C to 500°C for a predetermined time, then heated to a second temperature of 600°C to 800°C at a predetermined heating rate, and held at the second temperature for a predetermined time to crystallize the precursor layer. The holding time at the first temperature is, for example, 0.5 minutes to 3 minutes. The heating rate from the first temperature to the second temperature is, for example, 5°C / second to 40°C / second, preferably 7°C / second to 20°C / second. The holding time at the second temperature is, for example, 1 minute to 5 minutes.

[0052] As a result, a crystalline layer 42 consisting of a KNN layer containing additives can be formed. Then, the series of steps from coating the precursor solution to firing the precursor layer is repeated multiple times. This allows for the formation of a piezoelectric layer 40 consisting of multiple crystalline layers 42.

[0053] In the process of forming the piezoelectric layer 40, the heating device used for drying and degreasing the precursor layer is, for example, a hot plate. The heating device used for firing the precursor layer is, for example, an infrared lamp annealing apparatus.

[0054] Next, the piezoelectric layer 40 and the orientation control layer 30 are patterned, for example, by photolithography and etching. Then, the second electrode 50 is formed on the piezoelectric layer 40 and the substrate 10. The second electrode 50 is formed, for example, by sputtering or vacuum deposition.

[0055] By following the above steps, the piezoelectric element 100 can be manufactured.

[0056] 3. Liquid dispensing head Next, the liquid discharge head according to this embodiment will be described with reference to the drawings. Figure 3 is a schematic exploded perspective view showing the liquid discharge head 200 according to this embodiment. Figure 4 is a schematic plan view showing the liquid discharge head 200 according to this embodiment. Figure 5 is a schematic cross-sectional view of the liquid discharge head 200 according to Figure 4, taken along line VV. In Figures 3 to 5, the X-axis, Y-axis, and Z-axis are shown as three mutually orthogonal axes.

[0057] As shown in Figures 3 to 5, the liquid discharge head 200 includes, for example, a pressure chamber substrate 210, a communication plate 220, a nozzle plate 230, a compliance substrate 240, a protective substrate 250, a case member 260, and a wiring board 270. For convenience, the communication plate 220, nozzle plate 230, compliance substrate 240, protective substrate 250, and case member 260 are omitted from the illustration in Figure 4.

[0058] As shown in Figure 3, the pressure chamber substrate 210 is provided between the communication plate 220 and the protective substrate 250. As shown in Figures 4 and 5, a plurality of pressure chambers 212 are formed in the pressure chamber substrate 210. In the example shown in Figure 4, the plurality of pressure chambers 212 are arranged in a line along the Y-axis, and two rows of pressure chambers 212 arranged along the Y-axis are arranged in a line along the X-axis. The arrangement of the plurality of pressure chambers 212 is not particularly limited.

[0059] The planar shape of the pressure chamber 212 formed on the pressure chamber substrate 210 is a rectangle in which the size in the X-axis direction is larger than the size in the Y-axis direction. However, the planar shape of the pressure chamber 212 is not particularly limited and may be a parallelogram, polygon, circle, oval, etc. An oval shape is a shape based on a rectangle with semicircular ends in the longitudinal direction, and includes rounded rectangles, ellipses, and egg shapes. For the pressure chamber substrate 210, for example, a silicon substrate, a glass substrate, an SOI (Silicon On Insulator) substrate, or a ceramic substrate can be used.

[0060] As shown in Figure 3, the communication plate 220 is provided in the -Z-axis direction of the pressure chamber substrate 210. The communication plate 220 is provided between the pressure chamber substrate 210 and the nozzle plate 230. A nozzle communication passage 222 is formed in the communication plate 220, which connects the pressure chamber 212 and the nozzle 232.

[0061] As shown in Figure 5, the communication plate 220 has a first manifold section 224 and a second manifold section 226 formed therein, which constitute part of the manifold 280. The manifold 280 is a common liquid chamber through which multiple pressure chambers 212 communicate. The first manifold section 224 penetrates the communication plate 220 in the Z-axis direction. The second manifold section 226 does not penetrate the communication plate 220 in the Z-axis direction, but has an opening in the -Z-axis direction. The communication plate 220 also has a supply passage 228 formed therein that communicates with one end of the pressure chamber 212 in the X-axis direction. The supply passage 228 communicates the second manifold section 226 with each pressure chamber 212. The supply passage 228 supplies ink from the manifold 280 to the pressure chambers 212.

[0062] As the connecting plate 220, for example, a metal substrate such as a silicon substrate, glass substrate, SOI substrate, ceramic substrate, or stainless steel substrate is used. It is preferable that the difference between the thermal expansion coefficient of the connecting plate 220 and the thermal expansion coefficient of the pressure chamber substrate 210 is small. This reduces warping that occurs in the connecting plate 220 and the pressure chamber substrate 210 due to the difference in thermal expansion coefficients, even when the temperatures of the connecting plate 220 and the pressure chamber substrate 210 change.

[0063] As shown in Figure 3, the nozzle plate 230 is provided in the -Z axis direction of the communication plate 220. The nozzle plate 230 has nozzles 232 that communicate with the pressure chamber 212 via nozzle communication passages 222. Multiple nozzles 232 are formed. In the illustrated example, the multiple nozzles 232 are arranged in a line in the Y axis direction, and two rows of nozzles 232 arranged in the Y axis direction are arranged in the X axis direction. The arrangement of the nozzles 232 is not particularly limited.

[0064] For the nozzle plate 230, for example, a metal substrate such as a silicon substrate, glass substrate, SOI substrate, ceramic substrate, or stainless steel substrate can be used. The material of the nozzle plate 230 may also be an organic material such as polyimide resin. It is preferable that the difference between the thermal expansion coefficient of the nozzle plate 230 and the thermal expansion coefficient of the connecting plate 220 is small. This reduces warping that occurs in the nozzle plate 230 and the connecting plate 220 due to the difference in thermal expansion coefficients, even when the temperature of the nozzle plate 230 and the connecting plate 220 changes.

[0065] The compliance substrate 240 is provided in the -Z-axis direction of the communication plate 220. The compliance substrate 240 surrounds the nozzle plate 230 when viewed from the Z-axis direction. As shown in Figure 5, the compliance substrate 240 seals the openings of the first manifold portion 224 and the second manifold portion 226 formed in the communication plate 220. The compliance substrate 240 has, for example, a sealing film 242 made of a flexible thin film and a fixed substrate 244 made of a hard material such as metal. An opening 246 that penetrates in the Z-axis direction is formed in the portion of the fixed substrate 244 facing the manifold 280. Due to the opening 246, one side of the manifold 280 becomes a compliance portion 282 sealed only by the flexible sealing film 242.

[0066] As shown in Figure 3, the protective substrate 250 is provided in the +Z axis direction of the pressure chamber substrate 210. The protective substrate 250 is provided between the pressure chamber substrate 210 and the case member 260. The protective substrate 250 is bonded to the pressure chamber substrate 210 by an adhesive or the like. As shown in Figure 5, the protective substrate 250 has a holding portion 252 which is a space for protecting the piezoelectric element 100. Multiple holding portions 252 are formed to correspond to multiple piezoelectric elements 100. Between adjacent holding portions 252 in the X axis direction, through holes 254 are formed that penetrate the protective substrate 250 in the Z axis direction.

[0067] The case member 260 is provided in the +Z axis direction of the protective substrate 250. The case member 260, together with the pressure chamber substrate 210, defines a manifold 280 that communicates with a plurality of pressure chambers 212. When viewed from the Z axis direction, the case member 260 has substantially the same shape as, for example, the communication plate 220. The case member 260 is joined to the protective substrate 250 and the communication plate 220.

[0068] The case member 260 has a housing section 262 formed on the protective substrate 250 side for housing the pressure chamber substrate 210 and the communication plate 220. With the pressure chamber substrate 210 and the communication plate 220 housed in the housing section 262, the communication plate 220 is provided at the opening of the housing section 262 on the nozzle plate 230 side.

[0069] The case member 260 has a third manifold section 264 formed on each of the outer sides of the housing section 262 in the X-axis direction. The manifold 280 is composed of the first manifold section 224 and the second manifold section 226 formed on the communication plate 220 and the third manifold section 264 formed on the case member 260. The manifold 280 is formed continuously along the Y-axis direction.

[0070] The case member 260 has a supply port 266 for supplying ink to the manifold 280. The case member 260 also has a through hole 268 that communicates with a through hole 254 formed in the protective substrate 250.

[0071] The wiring board 270 is inserted into through holes 268 formed in the case member 260 and through holes 254 formed in the protective substrate 250. The wiring board 270 has an integrated circuit 272 for driving the piezoelectric element 100. The wiring board 270 is, for example, FPC (Flexible Printed Circuit). It consists of a Printed Circuit (FFC) and a Flexible Flat Cable (FFC).

[0072] The liquid discharge head 200 includes, for example, a piezoelectric element 100, as shown in Figures 4 and 5. A plurality of piezoelectric elements 100 are provided. In the example shown in Figure 4, the plurality of piezoelectric elements 100 are arranged in a line along the Y-axis, and two rows of these Y-axis-aligned piezoelectric elements 100 are arranged in the X-axis direction. The arrangement of the piezoelectric elements 100 is not particularly limited. Also, for convenience, the piezoelectric elements 100 are simplified in Figures 4 and 5.

[0073] In multiple piezoelectric elements 100, the substrate 10 is common to all of them. In multiple piezoelectric elements 100, the substrate 10 constitutes a common substrate. As shown in Figure 5, the substrate 10 is composed of, for example, a diaphragm 12 and a pressure chamber substrate 210. The diaphragm 12 has, for example, a silicon oxide layer 14 and a zirconium oxide layer 16 provided on the silicon oxide layer 14.

[0074] In the plurality of piezoelectric elements 100, the first electrodes 20 are, for example, spaced apart from each other. In the plurality of piezoelectric elements 100, the first electrodes 20 constitute individual electrodes. That is, the first electrodes 20 are individually provided for the plurality of pressure chambers 212. As shown in Figure 4, the first electrodes 20 are provided with a width narrower than the width of the pressure chamber 212 in the direction of the Y axis.

[0075] Individual lead electrodes 290 are electrically connected to the first electrode 20. As shown in Figure 5, the individual lead electrodes 290 extend into through holes 254 formed in the protective substrate 250. In the through holes 254, the individual lead electrodes 290 are electrically connected to the wiring board 270. The material of the individual lead electrodes 290 is, for example, a metal such as copper or gold.

[0076] In the multiple piezoelectric elements 100, the piezoelectric layer 40 has a shape that extends in the X-axis direction, as shown in Figure 4, and is continuous with the piezoelectric layer 40 of adjacent piezoelectric elements 100 in the Y-axis direction at both ends in the X-axis direction. In the illustrated example, a groove 292 is formed between adjacent piezoelectric layers 40 in the Y-axis direction. The groove 292 does not overlap with the first electrode 20 when viewed from the Z-axis direction. In the groove 292, the piezoelectric layer 40 may be completely removed or may be formed thinner than other parts. The groove 292 allows the diaphragm 12 to be displaced more effectively.

[0077] In the multiple piezoelectric elements 100, the second electrode 50 is common to all of them. In the multiple piezoelectric elements 100, the second electrode 50 constitutes a common electrode. That is, the second electrode 50 is provided in common to multiple pressure chambers 212 arranged in the Y-axis direction.

[0078] A common lead electrode 294 is electrically connected to the second electrode 50. The common lead electrode 294 is provided, for example, on the second electrode 50. In the example shown in Figure 4, the common lead electrode 294 has a frame-like shape with an opening 296. The opening 296 reduces the deformation of the piezoelectric layer 40 caused by the common lead electrode 294. The common lead electrode 294 extends into a through hole 254 formed in the protective substrate 250. In the through hole 254, the common lead electrode 294 is electrically connected to the wiring board 270. The material of the common lead electrode 294 is, for example, a metal such as copper or gold.

[0079] In the liquid ejection head 200, a signal is supplied from the integrated circuit 272 to the first electrode 20, and a reference potential signal is supplied to the second electrode 50. This creates a potential difference between the first electrode 20 and the second electrode 50, and this potential difference deforms the piezoelectric layer 40. This deformation of the piezoelectric layer 40 deforms the diaphragm 12, and the volume of the pressure chamber 212 changes. The pressure change caused by the change in the volume of the pressure chamber 212 is then applied to the ink contained in the pressure chamber 212. As a result, the ink contained in the pressure chamber 212 is dispensed through the nozzle communication passage 222 into the nozzle. It is discharged from Ru232.

[0080] 4. Liquid discharge device Next, the liquid dispensing device according to this embodiment will be described with reference to the drawings. Figure 6 is a schematic perspective view showing the liquid dispensing device 300 according to this embodiment.

[0081] The liquid ejection device 300 includes, for example, a head unit 310, a carriage 320, a carriage shaft 322, a device body 330, a drive motor 340, a timing belt 342, a transport roller 350, and a printer controller 360, as shown in Figure 6. The liquid ejection device 300 is, for example, a serial printing inkjet printer that ejects ink as a liquid.

[0082] The head unit 310 includes, for example, a liquid ejection head 200. The number of liquid ejection heads 200 is not particularly limited. The head unit 310 is equipped with removable cartridges 312 and 314 that constitute a liquid supply means. The liquid ejection heads 200 eject ink supplied from cartridges 312 and 314.

[0083] The carriage 320 is equipped with the head unit 310. The carriage 320 is mounted on a carriage shaft 322 attached to the main body of the device 330 so as to be axially movable. In the liquid ejection device 300, the carriage 320 reciprocates along the carriage shaft 322, and ink is ejected from the liquid ejection head 200 onto the recording medium P being transported in the transport direction, thereby forming a desired image on the recording medium P. As the recording medium P, any printing material such as printing paper, resin film, or fabric can be used. In the illustrated example, the recording medium P is printing paper.

[0084] The drive motor 340 is mounted on the main body 330 of the device. The driving force of the drive motor 340 is transmitted to the carriage 320 via a plurality of gears (not shown) and a timing belt 342. As a result, the carriage 320 moves along the carriage shaft 322.

[0085] The transport roller 350 is provided on the main body 330 of the device. The transport roller 350 is a transport mechanism that moves the recording medium P relative to the liquid discharge head 200. The transport mechanism for transporting the recording medium P is not limited to a transport roller, but may also be a belt or a drum.

[0086] The printer controller 360 is a control unit that controls the liquid ejection head 200 and the drive motor 340. The printer controller 360 is electrically connected to the integrated circuit 272 of the liquid ejection head 200. The printer controller 360 includes, for example, a RAM (Random Access Memory) for temporarily storing various data, a ROM (Read Only Memory) for storing control programs, a CPU (Central Processing Unit), and a drive signal generation circuit that generates drive signals to be supplied to the liquid ejection head 200.

[0087] Furthermore, the liquid ejection device according to the present invention is not limited to serial printing inkjet printers, but may also be line printing inkjet printers. In addition, the liquid ejection device according to the present invention is not limited to inkjet printers, but may also be a colorant ejection device used in the manufacture of color filters for liquid crystal displays, an electrode material ejection device used in electrode formation for organic EL displays, FEDs (surface-emitting displays), etc., a bio-organic material ejection device used in biochip manufacturing, a three-dimensional molding device, a textile printing device, etc.

[0088] Furthermore, the piezoelectric element according to the present invention can be used in a wide range of applications, not limited to liquid ejection heads and printers. The piezoelectric element according to the present invention is suitably used as a piezoelectric actuator in, for example, ultrasonic motors, vibratory dust removal devices, piezoelectric transformers, piezoelectric speakers, piezoelectric pumps, and pressure-to-electrical conversion devices. The piezoelectric element according to the present invention is also suitably used as a piezoelectric sensor element in, for example, ultrasonic detectors, angular velocity sensors, acceleration sensors, vibration sensors, tilt sensors, pressure sensors, collision sensors, motion sensors, infrared sensors, terahertz sensors, heat detection sensors, pyroelectric sensors, and piezoelectric sensors. The piezoelectric element according to the present invention is also suitably used as a ferroelectric element in, for example, ferroelectric memory (FeRAM), ferroelectric transistors (FeFETs), ferroelectric arithmetic circuits (FeLogic), and ferroelectric capacitors. The piezoelectric element according to the present invention is also suitably used as a voltage-controlled optical element in, for example, wavelength converters, optical waveguides, optical path modulators, refractive index control elements, and electronic shutter mechanisms.

[0089] 5. Examples and Comparative Examples 5.1. Sample Preparation 5.1.1. Example 1 A silicon oxide layer with a thickness of 1460 nm was formed by thermal oxidation of the surface of a single-crystal silicon substrate. Next, a zirconium layer with a thickness of 400 nm was deposited by DC (Direct Current) sputtering, and a zirconium oxide layer was formed by heat treatment at 850°C.

[0090] Next, a 20 nm thick titanium layer, an 80 nm thick platinum layer, and a 5 nm thick iridium layer were formed on the zirconium oxide layer by DC sputtering to create the first electrode.

[0091] Next, a BFTP precursor solution was prepared with a molar ratio of Bi:Pb:Fe:Ti = 110:10:50:50. The prepared BFTP precursor solution was then applied to the first electrode by spin coating, followed by drying at 180°C for 3 minutes, degreasing at 380°C for 3 minutes, and firing at 650°C for 3 minutes. As a result, a 20 nm thick BFTP layer was formed as an orientation control layer.

[0092] Next, a piezoelectric layer was formed by the sol-gel method. Specifically, elemental solutions consisting of potassium 2-ethylhexanoate, sodium 2-ethylhexanoate, and niobium 2-ethylhexanoate were synthesized. These elemental solutions were then (K 0.50 Na 0.50 ) 1.015 The mixture was prepared to form NbO3 to obtain a KNN precursor solution.

[0093] Next, the prepared KNN precursor solution was applied onto the BFTP layer by spin coating, dried at 240°C for 3 minutes, and degreased at 380°C for 3 minutes to form a KNN precursor layer. After returning to room temperature, the KNN precursor layer was held at 450°C for 1 minute, then the temperature was increased to 700°C at a heating rate of 10°C / second, and held at 700°C for 3 minutes to form a crystalline layer with a thickness of 100 nm. Then, by repeating the series of steps from applying the KNN precursor solution to firing the KNN precursor layer, a piezoelectric layer consisting of multiple crystalline layers was formed.

[0094] Next, a 50 nm thick platinum layer was formed on the piezoelectric layer by DC sputtering to create a second electrode. Then, the second electrode was patterned by photolithography and etching.

[0095] Based on the above, the sample for Example 1 was prepared.

[0096] 5.1.2. Example 2 The sample for Example 2 was prepared in the same manner as in Example 1 described above, except that the heating rate during firing was set to 40°C / second instead of 10°C / second.

[0097] 5.1.3. Example 3 As a precursor solution for forming a piezoelectric layer, a KNN precursor solution containing lithium, manganese, and copper as additives was used. Specifically, in addition to the simple substance solutions used in Example 1 described above, simple substance solutions composed of lithium 2-ethylhexanoate, manganese 2-ethylhexanoate, and copper 2-ethylhexanoate were used. These simple substance solutions were formulated so as to become (K 0.465 Na 0.465 Li 0.07 )(Nb 1.015 (Nb 0.984 Mn 0.01 Cu 0.006 )O3 to obtain a KNN precursor solution containing lithium, manganese, and copper. Furthermore, the number of layers of the crystal layer was changed.

[0098] Samples of Example 3 were prepared in the same manner as in Example 1 described above, except for the above.

[0099] 5.1.4. Comparative Example 1 A piezoelectric element having a piezoelectric layer composed of a KNN layer formed by sputtering, and a first electrode and a second electrode sandwiching the piezoelectric layer was used as a sample of Comparative Example 1.

[0100] 5.2. Evaluation Method In Examples 1 to 3 and Comparative Example 1, SIMS analysis was performed in the depth direction from the surface of the piezoelectric layer to the first electrode. As a measurement device, "IMS-7f" manufactured by CAMECA was used. As a primary ion beam, Cs with an acceleration energy of 15 keV and a current of 10 nA was irradiated onto the sample surface, and negative secondary ions were detected. In the measurement, it was set to a high mass resolution mode for the purpose of removing the influence of interfering ions, and an Au coating film was formed on the sample surface and electron beam irradiation was performed for the purpose of preventing charge-up that occurs during insulator measurement. + was irradiated onto the sample surface, and negative secondary ions were detected. In the measurement, it was set to a high mass resolution mode for the purpose of removing the influence of interfering ions, and an Au coating film was formed on the sample surface and electron beam irradiation was performed for the purpose of preventing charge-up that occurs during insulator measurement.

[0101] 5.3. Evaluation Results Figure 7 is a graph showing the SIMS analysis results for Examples 1 and 2. Figure 8 is a graph showing the SIMS analysis results for Comparative Example 1. Figure 9 is a graph showing the SIMS analysis results for Example 3.

[0102] Figures 7 and 8 show the results for potassium (K), sodium (Na), and niobium (Nb). In Figure 7, Example 1 is shown by a solid line, and Example 2 is shown by a dashed line. Figure 9 shows the results for potassium (K), sodium (Na), niobium (Nb), lithium (Li), manganese (Mn), copper (Cu), and oxygen (O2). Figures 7 to 9 show the strength normalized by oxygen. In Figures 7 and 9, the position of the interface between adjacent crystal layers is shown by a dashed line. In Figures 7 and 9, the horizontal axis represents the depth from the piezoelectric layer surface. In Figure 8, the horizontal axis represents the etching time corresponding to the depth from the piezoelectric layer surface.

[0103] In Examples 1 and 2, as shown in Figure 7, at the interface between adjacent crystal layers (hereinafter also referred to as the "interface position"), the intensity attributed to potassium was high and the intensity attributed to sodium was low. This indicates that at the interface position, the atomic concentration (at%) of potassium was higher than that of sodium. At the intermediate position between the interfaces of adjacent crystal layers (hereinafter also referred to as the "intermediate position"), the intensity attributed to potassium was low and the intensity attributed to sodium was high. This indicates that at the intermediate position, the atomic concentration (at%) of potassium was lower than that of sodium.

[0104] Therefore, the K / Na molar ratio at the interface is different from the K / Na molar ratio at the intermediate position. It was found that the amount was also large. Thus, in Examples 1 and 2, a compositional gradient of potassium and sodium was confirmed in the depth direction of the piezoelectric layer.

[0105] In Example 1, where the firing temperature was low, the intensity at the interface was greater for potassium and less for sodium compared to Example 2, where the firing temperature was high. Furthermore, in Example 1, compared to Example 2, the intensity at the intermediate position was greater for sodium and less for potassium. This indicates that reducing the firing temperature increases the compositional gradient of potassium and sodium in the depth direction of the piezoelectric layer.

[0106] Similar to potassium, niobium showed a high atomic concentration (at%) at the interface and a low atomic concentration (at%) at the intermediate position. However, the compositional gradient of niobium was smaller than that of potassium and sodium.

[0107] On the other hand, in Comparative Example 1, as shown in Figure 8, the compositional gradient of potassium, sodium, and niobium observed in Examples 1 and 2 was not confirmed.

[0108] In Example 3, as shown in Figure 9, a compositional gradient of potassium, sodium, and niobium was observed, similar to Examples 1 and 2. Similar to sodium, lithium had a low atomic concentration (at%) at the interface and a high atomic concentration (at%) at the intermediate position. Manganese and copper, similar to potassium, had a high atomic concentration (at%) at the interface and a low atomic concentration (at%) at the intermediate position.

[0109] When the leakage current of Examples 1-3 and Comparative Example 1 was measured, Examples 1-3, in which a compositional gradient of potassium and sodium was confirmed in the depth direction of the piezoelectric layer, showed lower leakage currents and higher insulation performance compared to Comparative Example 1, in which no compositional gradient of potassium and sodium was confirmed. This indicates that the insulation performance of the piezoelectric layer can be improved if the K / Na molar ratio at the interface is greater than the K / Na molar ratio at the intermediate position.

[0110] Furthermore, Examples 1 and 3, which had a slower heating rate during firing, exhibited lower leakage currents and higher insulation properties compared to Example 2, which had a higher firing temperature. A slower heating rate during firing increases the time difference between the crystallization of sodium niobate and potassium niobate, resulting in a more pronounced region of potassium niobate, which has higher insulation properties. Therefore, it is thought that Examples 1 and 3, with their slower heating rates, exhibited lower leakage currents compared to Example 2, which had a higher firing temperature.

[0111] The embodiments and variations described above are examples only and are not limiting. For example, each embodiment and each variation can be combined as appropriate.

[0112] The present invention includes configurations substantially identical to those described in the embodiments, for example, configurations with the same function, method, and results, or configurations with the same purpose and effect. Furthermore, the present invention includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. Furthermore, the present invention includes configurations that produce the same effects or achieve the same purpose as those described in the embodiments. Finally, the present invention includes configurations that add known technology to the configurations described in the embodiments.

[0113] The following can be derived from the embodiments and modifications described above.

[0114] One embodiment of a piezoelectric element is: circuit board and A first electrode provided on the substrate, A piezoelectric layer comprising potassium, sodium, and niobium is provided on the first electrode, A second electrode provided on the piezoelectric layer, Includes, The piezoelectric layer is A first layer provided on the first electrode, A second layer is provided on the first layer, It has, The piezoelectric layer is A first region including the first interface between the first layer and the second layer, A second region located within the first layer without including the first interface, It has, The molar ratio of potassium to sodium in the first region is greater than the molar ratio in the second region.

[0115] This piezoelectric element can improve the insulating properties of the piezoelectric layer.

[0116] In one embodiment of a piezoelectric element, In the first region, the atomic concentration of potassium (at%) is greater than the atomic concentration of sodium (at%). In the second region, the atomic concentration of potassium (at%) may be less than the atomic concentration of sodium (at%).

[0117] This piezoelectric element can promote crystal growth in the piezoelectric layer and improve the insulating properties of the piezoelectric layer.

[0118] In one embodiment of a piezoelectric element, The piezoelectric layer has a third layer provided on the second layer, The piezoelectric layer is A third region including the second interface between the second layer and the third layer, A fourth region located within the second layer without including the second interface, It has, The molar ratio in the third region may be greater than the molar ratio in the fourth region.

[0119] This piezoelectric element allows for further improvement of the insulating properties of the piezoelectric layer through the third region.

[0120] In one embodiment of a piezoelectric element, The atomic concentration (at%) of niobium in the first region may be greater than the atomic concentration (at%) of niobium in the second region.

[0121] This piezoelectric element can reduce niobium defects in the first region.

[0122] In one embodiment of a piezoelectric element, The difference between the atomic concentration (at%) of niobium in the first region and the atomic concentration (at%) of niobium in the second region may be smaller than the difference between the atomic concentration (at%) of potassium in the first region and the atomic concentration (at%) of potassium in the second region, and the difference between the atomic concentration (at%) of sodium in the first region and the atomic concentration (at%) of sodium in the second region.

[0123] This piezoelectric element can reduce niobium defects throughout the thickness direction of the piezoelectric layer.

[0124] In one embodiment of a piezoelectric element, The piezoelectric layer contains manganese, The atomic concentration (at%) of manganese in the first region may be greater than the atomic concentration (at%) of manganese in the second region.

[0125] This piezoelectric element can reduce the stress generated in the piezoelectric layer.

[0126] In one embodiment of a piezoelectric element, The piezoelectric layer contains copper, The atomic concentration (at%) of copper in the first region may be greater than the atomic concentration (at%) of copper in the second region.

[0127] This piezoelectric element can reduce the stress generated in the piezoelectric layer.

[0128] In one embodiment of a piezoelectric element, The piezoelectric layer contains lithium, The atomic concentration (at%) of lithium in the second region may be greater than the atomic concentration (at%) of lithium in the first region.

[0129] This piezoelectric element can promote crystal growth in the piezoelectric layer.

[0130] In one embodiment of a piezoelectric element, A first electrode and the piezoelectric layer are provided, and include an orientation control layer containing bismuth, iron, titanium, and lead. The second region may be located between the orientation control layer and the first region.

[0131] This piezoelectric element can reduce the stress generated in the piezoelectric layer.

[0132] One embodiment of a liquid dispensing head is: This includes one embodiment of the piezoelectric element.

[0133] One embodiment of a liquid dispensing device is: Includes the aforementioned liquid dispensing head. [Explanation of symbols]

[0134] 10…Substrate, 12…Diaphragm, 14…Silicon oxide layer, 16…Zirconium oxide layer, 20…First electrode, 30…Orientation control layer, 40…Piezoelectric layer, 42…Crystal layer, 42a…First crystal layer, 42b…Second crystal layer, 42c…Third crystal layer, 43a…First interface, 43b…Second interface, 44…K-rich region, 44a…First K-rich region, 44b…Second K-rich region, 46…Na-rich region, 46a…First Na-rich region, 46b…Second Na-rich region, 50…Second electrode, 100…Piezoelectric element, 200…Liquid discharge head, 210…Pressure chamber substrate, 212…Pressure chamber, 2 20...Communication plate, 222...Nozzle communication passage, 224...First manifold section, 226...Second manifold section, 228...Supply communication passage, 230...Nozzle plate, 232...Nozzle, 240...Compliance substrate, 242...Sealing film, 244...Fixing substrate, 246...Opening, 250...Protective substrate, 252...Holding section, 254...Through hole, 260...Case member, 262...Housing section, 264...Third manifold section, 266...Supply port, 268...Through hole, 270...Wiring board, 272...Integrated circuit, 280...Manifold, 282...Compliance section, 290...Individual reed Lead electrode, 292…groove section, 294…common lead electrode, 296…opening, 300…liquid discharge device, 310…head unit, 312,314…cartridge, 320…carriage, 322…carriage shaft, 330…device body, 340…drive motor, 342…timing belt, 350…conveyor roller, 360…printer controller

Claims

1. circuit board and A first electrode provided on the substrate, A piezoelectric layer comprising potassium, sodium, and niobium is provided on the first electrode, A second electrode provided on the piezoelectric layer, Includes, The piezoelectric layer is A first layer provided on the first electrode, A second layer provided on the first layer, It has, The piezoelectric layer is A first region including the first interface between the first layer and the second layer, A second region located within the first layer without including the first interface, It has, A piezoelectric element wherein the molar ratio of potassium to sodium in the first region is greater than the molar ratio in the second region.

2. In claim 1, In the first region, the atomic concentration of potassium (at%) is greater than the atomic concentration of sodium (at%). A piezoelectric element in which, in the second region, the atomic concentration of potassium (at%) is less than the atomic concentration of sodium (at%).

3. In claim 1, The piezoelectric layer has a third layer provided on the second layer, The piezoelectric layer is A third region including the second interface between the second layer and the third layer, A fourth region located within the second layer without including the second interface, It has, A piezoelectric element wherein the molar ratio in the third region is greater than the molar ratio in the fourth region.

4. In claim 1, A piezoelectric element wherein the atomic concentration (at%) of niobium in the first region is greater than the atomic concentration (at%) of niobium in the second region.

5. In claim 1, A piezoelectric element wherein the difference between the atomic concentration (at%) of niobium in the first region and the atomic concentration (at%) of niobium in the second region is smaller than the difference between the atomic concentration (at%) of potassium in the first region and the atomic concentration (at%) of potassium in the second region, and the difference between the atomic concentration (at%) of sodium in the first region and the atomic concentration (at%) of sodium in the second region.

6. In claim 1, The piezoelectric layer contains manganese, A piezoelectric element wherein the atomic concentration (at%) of manganese in the first region is greater than the atomic concentration (at%) of manganese in the second region.

7. In claim 1, The piezoelectric layer contains copper, A piezoelectric element wherein the atomic concentration (at%) of copper in the first region is greater than the atomic concentration (at%) of copper in the second region.

8. In claim 1, The piezoelectric layer contains lithium, A piezoelectric element wherein the atomic concentration (at%) of lithium in the second region is greater than the atomic concentration (at%) of lithium in the first region.

9. In claim 1, A first electrode and the piezoelectric layer are provided, and include an orientation control layer containing bismuth, iron, titanium, and lead. The second region is a piezoelectric element located between the orientation control layer and the first region.

10. A liquid dispensing head comprising a piezoelectric element according to any one of claims 1 to 9.

11. A liquid dispensing device comprising the liquid dispensing head described in claim 10.

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