Piezoelectric Materials and Devices

Abstract

A piezoelectric material and a piezoelectric device, comprising: a substrate, the crystal structure of the substrate being an ABO3 type perovskite structure, the perovskite structure including coexisting rhombohedral and tetragonal structures, the substrate being located near a homomorphic phase boundary, and a doping element, the doping element being used to replace an A-site element or a B-site element in the perovskite structure or to fill gaps in the perovskite structure, the doping element being used to increase the difference in lattice constant between the rhombohedral structure and the tetragonal structure.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to the field of piezoelectric technology, and in particular to piezoelectric materials and devices. [Background technology]

[0002] A tactile reproduction device based on a piezoelectric material can adjust the friction force on the substrate surface by resonating between a piezoelectric material layer and a substrate, thereby realizing the reproduction of the texture of an object on the substrate surface.

[0003] However, affected by the inherent properties of the material, the piezoelectric effect of the conventional piezoelectric material is small, which limits its further widespread application in touch reproduction devices. Summary of the Invention

[0004] The present disclosure provides a piezoelectric material, the piezoelectric material comprising a substrate and a doping element; The crystal structure of the substrate is an ABO3 type perovskite structure, the perovskite structure includes a coexisting rhombohedral structure and a tetragonal structure, and the substrate is located near a homomorphic phase boundary; The doping elements are used to substitute A-site elements or B-site elements in the perovskite structure or to fill gaps in the perovskite structure, and the doping elements are used to increase the difference in lattice constants between the rhombohedral structure and the tetragonal structure.

[0005] In one alternative realization, the substrate is lead zirconate titanate, in which the ratio of titanate to zirconate is 52:48 or 53:47.

[0006] In one alternative implementation, the doping element is used to replace an A-site element in the perovskite structure, and the valence of the doping element and the A-site element in the perovskite structure is the same.

[0007] In one alternative realisation, the substrate is lead zirconate titanate and the doping element is calcium.

[0008] In one alternative realisation, the molar percentage of said doping element in said substrate is less than or equal to 20%.

[0009] In one alternative realisation, the molar percentage of said doping element in said substrate is less than or equal to 10%.

[0010] In one alternative realization, the doping element is used to replace a B-site element in the perovskite structure, and the valence of the doping element and the B-site element in the perovskite structure is the same.

[0011] In one alternative realisation, the substrate is lead zirconate titanate and the doping element is manganese.

[0012] In one alternative realisation, the doping element is used to fill gaps in the perovskite structure, and the atomic weight of the doping element is less than or equal to 6.

[0013] In one alternative realisation, the substrate is lead zirconate titanate and the doping elements include at least one of carbon and boron.

[0014] The present disclosure provides a piezoelectric device, the piezoelectric device comprising: a substrate; and a piezoelectric element disposed on one side of the substrate, the piezoelectric element comprising a first electrode, a piezoelectric layer, and a second electrode disposed in a stacked manner on the one side of the substrate, wherein a material of the piezoelectric layer comprises a piezoelectric material as described in any of the embodiments.

[0015] In one optional implementation method, the substrate is a display substrate, the display substrate includes a display area and a non-display area located around the display area, and the piezoelectric element is provided on the light-emitting side of the display substrate.

[0016] In one optional implementation method, the orthogonal projection of the piezoelectric element on the display substrate is located within the display area, the thickness of the piezoelectric layer is less than 2 μm, and the first electrode and the second electrode are both transparent electrodes.

[0017] In one alternative embodiment, the thickness of the first electrode and the second electrode is greater than or equal to 200 nm and less than or equal to 500 nm.

[0018] In one selectable implementation method, the orthogonal projection of the piezoelectric elements on the display substrate is located within the non-display area, the number of the piezoelectric elements is multiple, and the multiple piezoelectric elements are divided into two groups, the piezoelectric elements in each group are arranged along a first direction and are respectively provided adjacent to two opposing sides of the substrate.

[0019] In one alternative embodiment, the material of the first electrode and the second electrode both includes platinum.

[0020] In one alternative embodiment, the film layer stresses of the first electrode, the piezoelectric layer and the second electrode are all greater than or equal to -300 MPa and less than or equal to 300 MPa.

[0021] In one alternative embodiment, the first electrode is disposed adjacent to the substrate, and an edge of the second electrode is recessed from an edge of the piezoelectric layer by an amount greater than or equal to 100 μm and less than or equal to 500 μm.

[0022] In one alternative implementation, the first electrode is grounded, and the second electrode is connected to an AC signal input terminal, the AC signal input terminal is used to input an AC signal, and the frequency of the AC signal is equal to the natural frequency of the substrate.

[0023] In one alternative embodiment, the piezoelectric device further includes a touch layer, the touch layer being disposed on a side of the piezoelectric element facing or facing away from the substrate.

[0024] The above description is only an outline of the technical solutions of the present disclosure, which can be implemented based on the contents of the specification in order to more clearly understand the technical solutions of the present disclosure, and in order to make the above and other objectives, features and advantages of the present disclosure more obvious, specific embodiments of the present disclosure are given below.

[0025] In order to more clearly describe the technical solutions in the embodiments of the present disclosure or related technologies, the following briefly introduces drawings that need to be used in the description of the embodiments or related technologies, and obviously, the drawings in the following description are some embodiments of the present disclosure, and those skilled in the art can further obtain other drawings based on these drawings without creative labor. It should be noted that the ratios in the drawings are merely illustrative and do not represent actual ratios. [Brief description of the drawings]

[0026] [Figure 1] FIG. 2 is a unit cell diagram of a perovskite structure according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a phase diagram for lead zirconate titanate according to an embodiment of the present disclosure. [Diagram 3] FIG. 13 is a diagram showing the change trend of the lattice constant according to an embodiment of the present disclosure. [Figure 4] FIG. 13 is a diagram showing a change trend of lattice strain according to an embodiment of the present disclosure. [Diagram 5] FIG. 2 is a schematic plan view of a structure of a piezoelectric device according to an embodiment of the present disclosure. [Figure 6] 1 is a schematic cross-sectional view of a structure of a piezoelectric device according to an embodiment of the present disclosure. [Figure 7] 2 is a schematic diagram of vibration of a piezoelectric device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] In order to make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present disclosure with reference to the drawings in the embodiments of the present disclosure, and obviously, the described embodiments are only some embodiments of the present disclosure, and not all embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative labor are all within the scope of protection of the present disclosure.

[0028] One embodiment of the present disclosure provides a piezoelectric material, which includes a substrate and a doping element.

[0029] Here, the crystal structure of the substrate is an ABO3 type perovskite structure, which includes a rhombohedral structure and a tetragonal structure coexisting therein, and the substrate is located near the homomorphic phase boundary.

[0030] Doping elements are used to substitute A-site elements or B-site elements in the perovskite structure or to fill gaps in the perovskite structure, and doping elements are used to increase the difference in lattice constants between the rhombohedral and tetragonal structures.

[0031] Figure 1 shows a unit cell diagram of the perovskite structure. The perovskite structure is an octahedron. In the ABO3 type perovskite structure, the A-site elements are located at the vertices of the octahedron, the B-site elements are located at the center points of the octahedron, and the O-site elements are located at the face-center positions of the octahedron.

[0032] The piezoelectric and ferroelectric performance of the perovskite structure can be modified by substitutional doping or interstitial doping, where substitutional doping can be achieved by the doping element substituting the A-site element or the B-site element, and interstitial doping can be achieved by the doping element filling the interstices in the perovskite structure.

[0033] In a substrate near a morphotropic phase boundary (MPB), two phases (corresponding to two crystal structures, a rhombohedral structure and a tetragonal structure) coexist, the energies of the two crystal structures are close, and when the external conditions change, for example when an electric field or stress is applied, interconversion between the two crystal structures occurs, and the components near the morphotropic phase boundary have maximum dielectric and piezoelectric properties.

[0034] In one alternative implementation, the substrate is lead zirconate titanate, although the present embodiment is not limited thereto.

[0035] In one possible implementation, the doping element is an element such as calcium, carbon or boron, but the embodiment is not limited thereto.

[0036] In this embodiment, an example in which the material of the substrate is lead zirconate titanate and the doping element is calcium is taken for explanation.

[0037] Lead zirconate titanate has an ABO3 type perovskite structure, where the A site is Pb 2+ and the B site is Zr 4+ Or Ti 4+ It is.

[0038] Figure 2 shows the phase diagram of lead zirconate titanate. Lead zirconate titanate is a solid solution of lead zirconate (PbZrO3) and lead titanate (PbTiO3). The zirconium-rich component has a rhombohedral structure and the titanium-rich component has a tetragonal structure. When the ratio of titanate to zirconate in lead zirconate titanate is 52:48 or 53:47, the lead zirconate titanate lies near the homomorphic phase boundary.

[0039] Without doping, the components of the base lead zirconate titanate are located near the homomorphic phase boundary, and two phases, rhombohedral and tetragonal structures, coexist. 2+ With increasing doping, the two phases still coexist, i.e., Ca 2+We found that doping does not affect the existence of the homomorphic phase boundary region.

[0040] In Figure 3, Ca 2+ With increasing content of Pb 1-x Ca x Zr 0.53 Ti 0.47 As can be seen in Fig. 3, the lattice constant of CaO3 changes. 2+ With increasing content, the lattice constant a of the rhombohedral structure R increases, and the short axis lattice parameter a of the square structure increases accordingly. T also increases, but a T The increase in speed is a R Since the lattice constant a of the rhombohedral structure is R and the minor axis lattice constant a of the square structure T The difference between the lattice constant a of the rhombohedral structure increases. R As increases, the long axis lattice constant c of the square structure T As the lattice constant a of the rhombohedral structure gradually decreases, R and the long axis lattice constant c of the square structure T The difference between the lattice constant a of the rhombohedral structure also increases. R and the lattice constant a of the square structure T or c T The difference value between increases.

[0041] The source of distortion near the homomorphic phase boundary is mainly the mutual transition between the tetragonal and rhombohedral phases. Figure 4 shows the amount of lattice distortion that occurs during the phase transition. As shown in Figure 4, 2+ With the increase in the content of , the lattice constant of the rhombohedral structure (a R ) and the lattice constant of the square structure (a T or c T ) difference increases, so the amount of lattice distortion (a R -a T ) / a T or (a R -c T ) / c T increases together. Here, (a R -a T ) / a Tis the minor axis a of the tetragonal phase T Both are a R represents the amount of distortion caused by converting to (a R -c T ) / c T is the long axis of the tetragonal phase c T Both are a R The actual lattice distortion amount lies between these two.

[0042] Ca 2+ The doping of Pb does not affect the existence of the homomorphic phase boundary region. 1-x Ca x Zr 0.53 Ti 0.47 O3 still exhibits the coexistence of rhombohedral structure (rhombohedral phase) and tetragonal structure (tetragonal phase), and when an electric field is applied, a phase structure transition is likely to occur between the rhombohedral structure and the tetragonal structure, and when the difference in lattice constant between the rhombohedral structure and the tetragonal structure increases, the maximum lattice strain of the strained material can be increased.

[0043] Therefore, increasing the difference in lattice constants between the two phases (i.e., the rhombohedral phase and the tetragonal phase) near the homomorphic phase boundary component, i.e., increasing the difference in lattice constants before and after the phase transition, is advantageous in generating large strain and increasing the maximum value of the intrinsic strain.

[0044] The piezoelectric material according to the present embodiment is a perovskite structure substrate doped with a doping element, and is located near the homomorphic phase boundary, and the material located near the homomorphic phase boundary is prone to mutual transition between the rhombohedral structure and the tetragonal structure under the action of an external electric field. The doping element can increase the difference in lattice constant between the rhombohedral structure and the tetragonal structure, so that the amount of lattice distortion caused by the phase transition can be increased, the maximum value of the inherent distortion can be improved, and the piezoelectric effect of the piezoelectric material can be reinforced. By improving the maximum value of the inherent distortion of the piezoelectric material, the amplitude of the piezoelectric device can be improved, and the effective conversion of electrical energy and mechanical energy can be realized, which is favorable to increasing the tactile sensation and improving the effect of tactile reproduction.

[0045] The piezoelectric material according to the present embodiment can realize mutual conversion between mechanical energy and electrical energy, and can generate electric charges when subjected to mechanical pressure or tension, and undergo mechanical deformation such as compression or tension when the material is in an electric field, and can therefore be applied in fields such as ultrasonic probes, pressure sensors, energy collectors, tactile reproduction, microfluidics, drivers and sensors for speakers, etc.

[0046] The piezoelectric material according to the present embodiment can be fabricated using methods such as sol-gel, magnetron sputtering, chemical vapor deposition, etc. Here, the sol-gel method allows precise control of the composition and doping ratio of the film layer.

[0047] When the material of the substrate is lead zirconate titanate, in the manufacturing process, the lead zirconate titanate film layer needs to be rapidly annealed at high temperature (>550°C) and oxygen gas atmosphere for 30 min, thereby forming the perovskite crystal phase. Excess Pb of less than 20 mol% (mol percent 20%) can be added during the preparation of the sol-gel solution or during the manufacture of the magnetron sputtering target, and the ratio of titanate to zirconate is Zr / Ti=52 / 48 or 53 / 47, making the substrate located near the homomorphic phase boundary. The doping element can be added during the preparation of the sol-gel solution or during the manufacture of the magnetron sputtering target.

[0048] When the doping of the doping element into the substrate is substitutional doping, the doping element and the substitution target element may be equivalent doping or non-equivalent doping. Here, non-equivalent doping refers to doping with ions having different valences relative to the substitution target element, including donor doping and acceptor doping, such as La 3+ Pb 2+ Equivalent doping is done by doping with ions that have the same valence as the element to be substituted, for example, Ca 2+ Pb 2+ etc.

[0049] The inventors have discovered that when non-equivalent doping is performed on the substrate, if too much donor or acceptor element is added, the ionic balance is easily lost, the amount of positive / negative charge increases, and a non-uniform built-in electric field is generated inside the piezoelectric material, which ultimately makes the thin film more susceptible to destruction.

[0050] In order to solve the ion imbalance problem, in one possible implementation, a doping element is used to replace the A-site element in the perovskite structure, and the valence of the doping element and the A-site element in the perovskite structure are the same. In this way, the equivalent substitution doping of the A-site element can be performed without affecting the leakage current and dielectric constant of the piezoelectric material, and the ion imbalance problem caused by excessive doping can be avoided.

[0051] In a specific embodiment, when the substrate is lead zirconate titanate, the A-site elements are Pb 2+ and the doping element substituting the A site may be calcium, i.e., Ca 2+ Pb 2+ Replace with.

[0052] To ensure that the piezoelectric material always lies near the homomorphic phase boundary, the mole percentage of the doping element in the substrate may be 20% or less. 2+ and Ca 2+ ) doping element Ca 2+ The mole percentage of is less than or equal to 20%. In a specific implementation, as shown in FIG. 3 and FIG. 4, the mole percentage of the doping element in the substrate may be less than 10%.

[0053] In order to solve the ion imbalance problem, in another possible implementation, the doping element is used to substitute the B-site element in the perovskite structure, and the valence of the doping element and the B-site element in the perovskite structure are the same. In this way, the equivalent substitution doping of the B-site element can be performed without affecting the leakage current and dielectric constant of the piezoelectric material, and the ion imbalance problem caused by excessive doping can be avoided.

[0054] In a specific embodiment, when the substrate is lead zirconate titanate, the B-site element is Zr 4+ Or Ti 4+ and the doping element substituting the B site may be manganese, i.e., Mn 4+ Zr 4+ Or Ti 4+ Replace with.

[0055] In one alternative implementation, doping elements are used to fill gaps in the perovskite structure, and the atomic weight of the doping elements may be 6 or less.

[0056] For example, when the substrate is lead zirconate titanate, the doping element doped into the interstices may include at least one of carbon and boron.

[0057] An embodiment of the present disclosure provides a piezoelectric device. As shown in Fig. 5, the piezoelectric device includes a substrate 51 and a piezoelectric element 52 provided on one side of the substrate 51. As shown in Fig. 6, the piezoelectric element 52 includes a first electrode 61, a piezoelectric layer 62, and a second electrode 63 that are laminated on one side of the substrate 51. Here, the material of the piezoelectric layer 62 may include the piezoelectric material described in any of the above embodiments.

[0058] Here, the substrate 51 may be a silicon-based substrate, or a silicon-based substrate provided with a thermal oxidation layer, i.e., SiO2 / Si(100). The substrate 51 may further be a transparent glass substrate, a display substrate, etc., and the present embodiment is not limited thereto.

[0059] The material of the first electrode 61 may include at least one of metal materials such as platinum, gold, aluminum, and copper, and may further include at least one of transparent metal oxides such as indium tin oxide (ITO), indium zinc oxide (IZO), and graphene oxide, but this embodiment is not limited thereto.

[0060] The material of the second electrode 63 may include at least one of metal materials such as platinum, gold, aluminum, and copper, and may further include at least one of transparent metal oxides such as indium tin oxide (ITO), indium zinc oxide (IZO), and graphene oxide, but this embodiment is not limited thereto.

[0061] In this embodiment, the shape of the piezoelectric element 52 is not limited, and it may be a circle as shown in FIG. 5, or a rectangle, a pentagon, a hexagon, or the like.

[0062] In this embodiment, the first electrode 61 and the second electrode 63 are used to generate an alternating electric field, and the piezoelectric layer 62 is used to vibrate under the action of the alternating electric field, driving the substrate 51 to resonate.

[0063] Under the action of the alternating electric field, the piezoelectric layer 62 deforms to generate a vibration signal, and the frequency of the vibration signal is the same as the frequency of the alternating electric field. When the frequency of the vibration signal is close to or equal to the natural frequency of the substrate 51, the piezoelectric layer 62 resonates with the substrate 51, and the amplitude is reinforced to generate a tactile feedback signal. When a finger touches the surface of the piezoelectric device, the change in friction force can be felt noticeably. Therefore, the friction force on the surface of the piezoelectric device can be adjusted by the resonance generated between the piezoelectric layer 62 and the substrate 51, thereby realizing the texture reproduction of the object.

[0064] The piezoelectric device according to this embodiment has a large inherent strain of the piezoelectric material, and therefore can improve the resonance amplitude between the piezoelectric layer and the substrate, increase the surface feel, and improve the effect of tactile reproduction.

[0065] In one possible implementation, the piezoelectric device according to this embodiment may further include a touch layer, which is provided on a side of the piezoelectric element 52 that is close to or far from the substrate 51. That is, the touch layer may be provided between the substrate 51 and the piezoelectric element 52, or may be provided on a side of the piezoelectric element 52 that is far from the substrate 51. By providing the touch layer, the piezoelectric device can have a touch function.

[0066] To avoid film breakage, the film layer stress of the first electrode 61 may be -300 MPa or more and 300 MPa or less, with a maximum of 400 MPa. The film layer stress of the piezoelectric layer 62 may be -300 MPa or more and 300 MPa or less, with a maximum of 400 MPa. The film layer stress of the second electrode 63 may be -300 MPa or more and 300 MPa or less, with a maximum of 400 MPa. In this way, breakage of each film layer due to excessive stress and warping of the entire substrate 51 can be prevented.

[0067] Here, the stress of each film layer can be calculated by testing the degree of surface warpage before and after the preparation of the film layer, and calculating the stress of the corresponding film layer based on the measured degree of surface warpage.

[0068] In a specific implementation, as shown in FIG. 6, the first electrode 61 may be provided adjacent to the substrate 51 .

[0069] 6, the edge of the second electrode 63 is recessed from the edge of the piezoelectric layer 62. That is, the orthogonal projection boundary of the second electrode 63 on the substrate 51 is recessed from the orthogonal projection boundary of the piezoelectric layer 62 on the substrate 51. In this way, the problem of the first electrode 61 and the second electrode 63 directly contacting each other due to the severe side etching of the piezoelectric layer 62 can be avoided.

[0070] The edge recession amount of the piezoelectric layer 62 from the edge of the second electrode 63 may be 100 μm or more and 500 μm or less. In this way, the effective vibration area of ​​the piezoelectric layer 62 can be increased while avoiding the occurrence of a short circuit between the first electrode 61 and the second electrode 63.

[0071] The piezoelectric device according to this embodiment can be manufactured in the following steps. First, a substrate 51 is prepared. Next, a first electrode material layer, a piezoelectric material layer, and a second electrode material layer are formed in sequence on the substrate 51. Next, the second electrode material layer is etched to form a second electrode. Next, the piezoelectric material layer is etched to form a piezoelectric layer. Finally, the piezoelectric device shown in FIG. 6 is obtained.

[0072] In a specific implementation, the shapes of the piezoelectric layer 62 and the second electrode 63 may be the same. Referring to Figures 5 and 6, the second electrode 63 is a circle with a diameter of 8 mm, and the second electrode 63 is a circle with a diameter of 9 mm. The piezoelectric layer 62 is slightly larger than the second electrode 63, because the edge of the second electrode 63 is recessed from the edge of the piezoelectric layer 62, and in Figure 6, the edge of the second electrode 63 is recessed from the edge of the piezoelectric layer 62 by 500 μm.

[0073] 6, the distance between the orthogonal projection boundary of the second electrode 63 on the substrate 51 and the boundary of the substrate 51 may be 3 mm. In FIG. 5, the dimensions of the substrate 51 are 71 mm*60 mm.

[0074] 5, the substrate 51 may be, for example, a display substrate, and the display substrate includes a display area AA and a non-display area BA located around the display area AA. Since the substrate 51 is a display substrate, the piezoelectric device can have a display function.

[0075] The piezoelectric element 52 can be provided on the light output side of the display substrate, but this embodiment is not limited to this.

[0076] In one possible implementation, the orthogonal projection of the piezoelectric element 52 on the display substrate may be located within the display area AA. In order not to affect the transmittance of the display substrate, the thickness of the piezoelectric layer 62 may be 2 μm or less. When the thickness of the piezoelectric layer 62 is 2 μm or less, the film layer transmittance of 70% or more can be guaranteed, and the tactile reproduction device can be integrated with the display substrate to manufacture the device.

[0077] In order not to affect the transmittance of the display substrate, the first electrode 61 and the second electrode 63 may both be transparent electrodes. The first electrode 61 and the second electrode 63 may be made of a transparent metal oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), or graphene oxide.

[0078] In a specific implementation, the thickness of the first electrode 61 and the second electrode 63 may be, for example, 200 nm or more and 500 nm or less.

[0079] The first electrode 61 can be formed by depositing an ITO transparent oxide layer using magnetron sputtering, followed by annealing at 250 degrees Celsius in a nitrogen atmosphere for 30 minutes, to obtain a crystalline ITO film layer with low sheet resistance.

[0080] The piezoelectric layer 62 can be manufactured by sol-gel or magnetron sputtering, where the film layer growth rate of magnetron sputtering can reach 4 μm / h. The manufacturing process of the piezoelectric layer 62 can be referred to the manufacturing process of the piezoelectric material, and the description is omitted here.

[0081] The second electrode 63 can be formed by depositing an ITO transparent oxide layer using magnetron sputtering, followed by annealing at 250 degrees Celsius in a nitrogen atmosphere for 30 minutes to obtain a crystalline ITO film layer with low sheet resistance.

[0082] In another alternative implementation, the orthogonal projection of the piezoelectric element 52 on the display substrate is located within the non-display area BA. In this way, the piezoelectric element 52 does not affect the transmittance within the display area AA. Therefore, in this implementation, a metal material with low electrical resistivity can be used as the material for the first electrode 61 and the second electrode 63. For example, the material for the first electrode 61 and the second electrode 63 can be platinum. Platinum has excellent electrical conductivity, high-temperature thermal oxidation resistance, and compatibility with the lattice constant and piezoelectric layer 62, which can improve the performance and reliability of the piezoelectric device.

[0083] In this implementation, the thickness of the piezoelectric layer 62 can be designed according to actual needs, and generally, in order to ensure the film layer quality, the thickness of the piezoelectric layer 62 may be less than 10 μm.

[0084] In this implementation method, the number of piezoelectric elements 52 is multiple, and the multiple piezoelectric elements 52 are divided into two groups, and the piezoelectric elements 52 in each group are arranged along a first direction and may be provided adjacent to two opposing sides of the substrate 51, respectively.

[0085] The first electrodes 61 of the piezoelectric elements 52 in each group may be integral with each other. The second electrodes 63 of the piezoelectric elements 52 in each group may be provided separately and connected to each other by a lead wire.

[0086] In a specific implementation, as shown in Fig. 6, the first electrode 61 is grounded, and the second electrode 63 is connected to an AC signal input terminal, which is used to input an AC signal. The waveform of the AC signal may be a sine wave, a square wave, a triangular wave, etc.

[0087] The frequency of the AC signal may be the same as or close to the natural frequency of the substrate 51. The frequency of the AC signal is the frequency of the alternating electric field.

[0088] As shown in FIG. 7, when the substrate 51 is excited by a vibration signal close to its own natural frequency, it resonates with the piezoelectric element 52. When the frequency of the AC signal is 22.8KHz, the substrate 51 exhibits a vibration mode with 10 nodes in the second direction, and each node point does not move (the amplitude is always 0), and the position between the node points vibrates up and down, forming peaks and valleys. When the displacement between the peaks and valleys is greater than 1 μm, the finger slides on the touch surface, and the touch surface feels smoother. The larger the amplitude of the piezoelectric layer 62, the more intensely the air film between the finger and the touch surface is compressed, the friction force is significantly reduced, and the tactile sensation is significantly improved. Therefore, by improving the maximum value of the inherent strain of the piezoelectric layer 62 material, it is favorable to improve the overall amplitude of the device and realize excellent tactile feedback function.

[0089] Each embodiment in this specification is described in a stepwise manner, and the main points of each embodiment are the differences between the embodiments. The same or similar parts between the embodiments may be referred to each other.

[0090] Finally, as should be explained, in this specification, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not require or imply that any such actual relationship or ordering exists between those entities or operations. Also, the terms "comprise," "have," or other variations are intended to include non-exclusive inclusions, whereby a process, method, product, or apparatus that includes a set of elements not only includes those elements, but also includes other elements not expressly recited or that are inherent to such process, method, product, or apparatus. Absent more limitations, an element qualified by the phrase "comprises a ..." does not exclude the presence of further identical elements in the process, method, product, or apparatus that includes said element.

[0091] The above describes the piezoelectric material and piezoelectric device according to the present disclosure in detail, and the present disclosure uses specific examples to describe the principles and embodiments of the present disclosure, and the above description of the examples is for understanding the method and core idea of ​​the present disclosure. At the same time, those skilled in the art can make changes to the specific embodiments and application scope based on the ideas of the present disclosure, and as described above, the contents of the present disclosure should not be construed as limiting the present disclosure.

[0092] Other embodiments of the present disclosure will be readily apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. The present disclosure is intended to cover any modifications, uses or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or conventional technical means in the art that are not disclosed in the present disclosure. The specification and examples should be considered as merely exemplary, with the true scope and spirit of the present disclosure being indicated by the following claims.

[0093] It should be understood that the present disclosure is not limited to the exact configuration described above and illustrated in the drawings, and various modifications and changes can be made without departing from the scope thereof, which is limited only by the appended claims.

[0094] As used herein, the terms "one embodiment," "an embodiment," or "one or more embodiments" mean that a particular feature, structure, or characteristic described in an embodiment is included in at least one embodiment of the disclosure. Note that instances of the phrase "in one embodiment" herein do not necessarily all refer to the same embodiment.

[0095] In the specification provided herein, numerous specific details are set forth. However, it will be understood that embodiments of the present disclosure may be practiced without these specific details. In some embodiments, well-known methods, structures and techniques are not shown in detail so as not to obscure an understanding of this specification.

[0096] In the claims, any reference signs placed between parentheses shall not be constructed as a limitation on the scope of the claim. The word "comprise" does not exclude the presence of elements or steps not recited in the claim. The word "1" or "one" preceding an element does not exclude the presence of a plurality of such elements. The disclosure can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim reciting a plurality of apparatuses, a plurality of these apparatuses may be embodied by the same hardware item. The use of the words first, second, third, etc. does not indicate any order. These words can be interpreted as names.

[0097] Finally, the above embodiments are only used to explain the technical solutions of the present disclosure, and are not intended to limit the same. Although the present disclosure has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments, or replace some of the technical features thereof with equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A piezoelectric material, comprising: a substrate and a doping element, The crystal structure of the substrate is ABO ３ type perovskite structure, and the perovskite structure includes a coexisting rhombohedral structure and a tetragonal structure, and the substrate is located near a morphotropic phase boundary, wherein the substrate is lead zirconate titanate, when the doping element is used to replace the A-site element in the perovskite structure, the doping element is calcium, or when the doping element is used to replace the B-site element in the perovskite structure, the doping element is manganese, or when the doping element is used to fill the interstitial spaces in the perovskite structure, the doping element contains at least one of carbon and boron, the doping element is used to increase the difference in lattice constants between the rhombohedral structure and the tetragonal structure, the piezoelectric material.

2. The ratio of zirconium to titanium in the lead zirconate titanate is 52:48 or 53:47 The piezoelectric material according to Claim 1.

3. The doping element is used to replace the A-site element in the perovskite structure, the valence of the doping element and the A-site element in the perovskite structure is the same The piezoelectric material according to Claim 1 or 2.

4. The molar percentage of the doping element in the substrate is 20% or less The piezoelectric material according to Claim 3.

5. The molar percentage of the doping element in the substrate is 10% or less The piezoelectric material according to Claim 4.

6. The doping element is used to replace the B-site element in the perovskite structure, and the valence of the doping element and the B-site element in the perovskite structure is the same The piezoelectric material according to Claim 1 or 2.

7. A piezoelectric device, comprising: the piezoelectric device includes a substrate and a piezoelectric element provided on one side of the substrate, the piezoelectric element includes a first electrode, a piezoelectric layer, and a second electrode laminated and provided on one side of the substrate, wherein the material of the piezoelectric layer includes the piezoelectric material according to any one of Claims 1 to 6, the piezoelectric device.

8. The substrate is a display substrate, the display substrate includes a display area and a non-display area located around the display area, and the piezoelectric element is provided on the light-emitting side of the display substrate The piezoelectric element according to Claim 7.

9. The orthographic projection of the piezoelectric element on the display substrate is located within the display area, the thickness of the piezoelectric layer is 2 μm or less, and both the first electrode and the second electrode are transparent electrodes. The piezoelectric element according to claim 8.

10. The thicknesses of the first electrode and the second electrode are 200 nm or more and 500 nm or less. The piezoelectric element according to claim 9.

11. The orthographic projection of the piezoelectric element on the display substrate is located within the non-display area, the number of the piezoelectric elements is plural, the plural piezoelectric elements are divided into two groups, and the piezoelectric elements in each group are arranged along a first direction and are respectively provided close to two opposite side edges of the substrate. The piezoelectric element according to claim 8.

12. The materials of both the first electrode and the second electrode contain platinum. The piezoelectric element according to claim 11.

13. The film layer stresses of the first electrode, the piezoelectric layer, and the second electrode are all -300 MPa or more and 300 MPa or less. The piezoelectric element according to any one of claims 7 to 12.

14. The first electrode is provided close to the substrate, and the edge of the second electrode retreats by a retreat amount of 100 μm or more and 500 μm or less with respect to the edge of the piezoelectric layer. The piezoelectric element according to any one of claims 7 to 12.

15. The first electrode is grounded, the second electrode is connected to an AC signal input terminal, the AC signal input terminal is used to input an AC signal, and the frequency of the AC signal is equal to the natural frequency of the substrate. The piezoelectric element according to any one of claims 7 to 12.

16. The piezoelectric device further includes a touch layer, and the touch layer is provided on a side of the piezoelectric element close to or away from the substrate. The piezoelectric element according to any one of claims 7 to 12.

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