Piezoelectric element, piezoelectric vibrator, method for manufacturing and driving the same, and electronic device

Abstract

The application provides a piezoelectric element, a piezoelectric vibrator, a manufacturing and driving method thereof and an electronic device, and relates to the technical field of piezoelectricity. The application sets a piezoelectric structure on the first electrode, the piezoelectric structure has an opening penetrating through and exposing part of the first electrode, and a heat conduction structure is arranged in the opening. By forming the penetrating opening in the piezoelectric structure, the heat generation area of the piezoelectric structure during vibration is reduced, and the generated heat is also reduced. The heat conduction structure is added in the piezoelectric element, the heat generated by the piezoelectric structure during vibration is dissipated based on the heat conduction structure, the heat dissipation characteristics of the piezoelectric element are improved, and the problems of the piezoelectric structure being broken down and the resonance frequency of the piezoelectric structure being affected due to the excessively high temperature of the piezoelectric element are avoided.

Description

Technical Field

[0001] This application relates to the field of piezoelectric technology, and in particular to a piezoelectric element, a piezoelectric vibrator and its manufacturing and driving method, and electronic equipment. Background Technology

[0002] With the rapid advancement of electronic technology, people have increasingly higher demands for the user experience of electronic devices. Most current electronic devices can only provide visual and auditory experiences, but cannot provide users with tactile experiences. Therefore, tactile reproduction technology has emerged.

[0003] Currently, tactile reproduction technology involves placing piezoelectric elements in electronic devices to provide tactile feedback through the vibration of these elements. However, during use, the vibration of the piezoelectric structure causes the temperature of the element to rise, which can lead to breakdown of the piezoelectric structure and affect its resonant frequency. Summary of the Invention

[0004] This disclosure provides the following technical solutions through some embodiments:

[0005] In a first aspect, a piezoelectric element is provided, comprising: a first electrode and a piezoelectric structure disposed on the first electrode, wherein the piezoelectric structure has an opening that penetrates and exposes a portion of the first electrode in a direction perpendicular to the plane of the first electrode.

[0006] The piezoelectric element further includes a heat-conducting structure disposed within the opening, and the orthographic projection of the heat-conducting structure on the first electrode and the orthographic projection of the piezoelectric structure on the first electrode do not overlap.

[0007] Optionally, the aperture ratio of the piezoelectric structure is 10% to 70%.

[0008] Optionally, the piezoelectric element further includes a second electrode disposed on the side of the piezoelectric structure away from the first electrode, wherein the orthographic projection of the second electrode onto the first electrode lies within the orthographic projection of the piezoelectric structure onto the first electrode.

[0009] Optionally, in a direction perpendicular to the plane containing the first electrode, the thickness of the thermally conductive structure is less than or equal to the sum of the thicknesses of the piezoelectric structure and the second electrode.

[0010] Optionally, the thickness of the thermally conductive structure is 3 μm to 5 μm, the thickness of the piezoelectric structure is less than 5 μm, and the thickness of the second electrode is 100 nm to 1000 nm.

[0011] Optionally, the material of the thermally conductive structure is a thermally conductive metal.

[0012] In a second aspect, a piezoelectric vibrator is provided, comprising a substrate and at least one of the aforementioned piezoelectric elements disposed on the substrate, wherein the thermal conductivity of the thermally conductive structure is greater than the thermal conductivity of the substrate.

[0013] Thirdly, a method for manufacturing a piezoelectric vibrator is provided, including:

[0014] At least one first electrode is formed on the substrate;

[0015] A piezoelectric structure is formed on each of the first electrodes; each piezoelectric structure has an opening that penetrates and exposes a portion of the first electrode in a direction perpendicular to the plane containing the first electrode.

[0016] A heat-conducting structure is formed within each of the openings; the orthogonal projection of the heat-conducting structure onto the first electrode does not overlap with the orthogonal projection of the piezoelectric structure onto the first electrode.

[0017] Optionally, the step of forming a piezoelectric structure on each of the first electrodes includes:

[0018] A piezoelectric thin film is formed covering the first electrode and the substrate;

[0019] The piezoelectric thin film is subjected to high-temperature annealing and laser annealing.

[0020] The piezoelectric thin film is patterned to form a piezoelectric structure on each of the first electrodes.

[0021] Optionally, after the step of forming a thermally conductive structure within each of the openings, the method further includes:

[0022] A second electrode is formed on the side of each piezoelectric structure away from the first electrode; the orthogonal projection of the second electrode onto the first electrode lies within the orthogonal projection of the piezoelectric structure onto the first electrode.

[0023] Fourthly, a driving method for a piezoelectric vibrator is provided, applied to driving the aforementioned piezoelectric vibrator, the method comprising:

[0024] A first driving signal is input to the first electrode of the piezoelectric element, and a second driving signal is input to the second electrode of the piezoelectric element;

[0025] The second driving signal is divided into a first stage and a second stage. The second driving signal in the first stage is a pulse signal, and the voltage of the second driving signal in the second stage is a preset voltage. The voltage of the first driving signal is also the preset voltage.

[0026] Optionally, the ratio between the duration of the first stage and the duration of the second stage is 1:1 to 1:10.

[0027] Fifthly, an electronic device is provided, including the piezoelectric vibrator described above.

[0028] In this embodiment, a piezoelectric structure is provided on the first electrode, and the piezoelectric structure has an opening that penetrates and exposes part of the first electrode along a direction perpendicular to the plane of the first electrode. A heat-conducting structure is provided within the opening, and the orthogonal projection of the heat-conducting structure on the first electrode does not overlap with the orthogonal projection of the piezoelectric structure on the first electrode. By forming a through-hole in the piezoelectric structure, the area of ​​the piezoelectric structure in the piezoelectric element is reduced, thus reducing the heat-generating area of ​​the piezoelectric structure during vibration and consequently reducing the heat generated by the piezoelectric structure. Furthermore, by adding a heat-conducting structure to the piezoelectric element, the heat generated by the piezoelectric structure during vibration is dissipated, improving the heat dissipation characteristics of the piezoelectric element. This avoids the problem of the piezoelectric structure being broken down due to excessive temperature and affecting the resonant frequency of the piezoelectric structure, thereby improving the reliability of the piezoelectric structure.

[0029] The above description is merely an overview of the technical solution disclosed herein. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this disclosure more apparent and understandable, specific embodiments of this disclosure are listed below. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A cross-sectional view of a piezoelectric element according to an embodiment of this application is shown schematically;

[0032] Figure 2 A schematic plan view of a piezoelectric element according to an embodiment of this application is shown;

[0033] Figure 3 A cross-sectional view of another piezoelectric element according to an embodiment of this application is schematically shown;

[0034] Figure 4 A schematic plan view of a piezoelectric vibrator according to an embodiment of this application is shown.

[0035] Figure 5A cross-sectional view of a piezoelectric vibrator according to an embodiment of this application is schematically shown;

[0036] Figure 6 A flowchart illustrating a method for manufacturing a piezoelectric vibrator according to an embodiment of this application is shown schematically.

[0037] Figure 7 The XRD pattern of the piezoelectric structure in the embodiment of this application is shown schematically. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] Reference Figure 1 The diagram shows a cross-sectional view of a piezoelectric element according to an embodiment of this application. Figure 2 A plan view of a piezoelectric element according to an embodiment of this application is shown. Figure 1 The sectional view shown is along Figure 2 The sectional view of section A-A' in the middle.

[0040] This application provides a piezoelectric element 10, including a first electrode 11 and a piezoelectric structure 12 disposed on the first electrode 11. The piezoelectric structure 12 has an opening that penetrates and exposes a portion of the first electrode 11 along a direction perpendicular to the plane where the first electrode 11 is located. The piezoelectric element 10 also includes a heat-conducting structure 13 disposed in the opening, and the orthographic projection of the heat-conducting structure 13 on the first electrode 11 and the orthographic projection of the piezoelectric structure 12 on the first electrode 11 do not overlap.

[0041] In actual products, the first electrode 11 refers to the bottom electrode of the piezoelectric element 10, and the first electrode 11 can be a planar electrode with a rectangular shape. The material of the first electrode 11 is a transparent conductive material, such as ITO (Indium Tin Oxides), and the thickness h1 of the first electrode 11 along the direction perpendicular to the plane where the first electrode 11 is located is 100nm to 1000nm; of course, the material of the first electrode 11 can also be a general metal material, such as Au (gold) or In (indium). Since a metal material that is too thick can easily prevent light from passing through the first electrode 11, when the material of the first electrode 11 is a metal material, the thickness h1 of the first electrode 11 is set to be less than or equal to 20nm.

[0042] A piezoelectric structure 12 is provided on the first electrode 11, and the orthographic projection of the piezoelectric structure 12 on the first electrode 11 is located in the region where the first electrode 11 is located. The orthographic projection of the piezoelectric structure 12 on the first electrode 11 is annular, and the piezoelectric structure 12 has an opening that penetrates through and exposes part of the first electrode 11 along the direction perpendicular to the plane where the first electrode 11 is located. The shape of the opening can be any closed shape, such as a rectangle, a circle, a hexagon, etc.

[0043] The piezoelectric structure 12 is made of piezoelectric ceramic (PZT). For example, the piezoelectric ceramic can be a lead zirconate titanate binary piezoelectric ceramic with the chemical formula Pb(Zr) 1-x Ti x O3, which has an ABO3 perovskite structure.

[0044] When a through opening is formed in the piezoelectric structure 12, the area of ​​the piezoelectric structure 12 in the piezoelectric element 10 can be reduced, and the heating area of ​​the piezoelectric structure 12 during vibration is also reduced, and the heat generated by the piezoelectric structure 12 is also reduced accordingly.

[0045] Furthermore, a heat-conducting structure 13 is provided inside the opening formed by the piezoelectric structure 12. The heat-conducting structure 13 dissipates the heat generated by the piezoelectric structure 12 during vibration, thereby improving the heat dissipation characteristics of the piezoelectric element 10.

[0046] When the heat dissipation characteristics of the piezoelectric element 10 are poor, the temperature of the piezoelectric element 10 will rise. The increased temperature will lower the potential barrier between the electrodes on both sides of the piezoelectric structure 12, making it easier for electron transitions to occur between the electrodes on both sides of the piezoelectric structure 12, which will lead to the breakdown of the piezoelectric structure 12. Furthermore, the increased temperature of the piezoelectric element 10 will increase the dielectric loss of the piezoelectric structure 12, which will further increase the temperature of the piezoelectric element 10, making the piezoelectric structure 12 more susceptible to breakdown. In addition, the increased temperature of the piezoelectric element 10 will also cause the resonant frequency of the piezoelectric structure 12 to shift to a lower frequency, resulting in the frequency of the piezoelectric structure 12 during vibration not meeting the requirements.

[0047] The embodiments of this application improve the heat dissipation characteristics of the piezoelectric element 10 by reducing the heating area of ​​the piezoelectric structure 12 and adding a heat-conducting structure 13 in the piezoelectric element 10. This effectively prevents the temperature of the piezoelectric element 10 from becoming too high, thereby effectively preventing the piezoelectric structure 12 from being broken down. At the same time, it ensures that the frequency of the piezoelectric structure 12 during vibration meets the actual requirements, thus improving the reliability of the piezoelectric structure 12. In addition, it also reduces the temperature around the piezoelectric element 10, preventing the temperature from becoming too high and affecting the user's touch experience.

[0048] Furthermore, in actual products, the orthographic projection of the heat-conducting structure 13 on the first electrode 11 does not overlap with the orthographic projection of the piezoelectric structure 12 on the first electrode 11, meaning the heat-conducting structure 13 and the piezoelectric structure 12 are not in contact. If the heat-conducting structure 13 were in contact with the piezoelectric structure 12, the heat-conducting structure 13 would affect the vibration effect of the piezoelectric structure 12. Therefore, in this embodiment, by setting the orthographic projection of the heat-conducting structure 13 on the first electrode 11 to have no overlapping area with the orthographic projection of the piezoelectric structure 12 on the first electrode 11, the vibration effect of the piezoelectric structure 12 can be improved.

[0049] In this embodiment, the material of the heat-conducting structure 13 is a heat-conducting metal, such as aluminum (Al) or copper (Cu), which are metals with high thermal conductivity. The thermal conductivity of aluminum is 237 W / (mK).

[0050] Of course, the material of the thermally conductive structure 13 can also be replaced with other transparent thermally conductive materials, such as aluminum nitride, boron nitride, silicon carbide, magnesium oxide and aluminum oxide. The thermal conductivity of aluminum nitride is 80-320 W / (mk), that of boron nitride is 125 W / (mk), that of silicon carbide is 83.6 W / (mk), that of magnesium oxide is 36 W / (mk), and that of aluminum oxide is 30 W / (mk).

[0051] When aluminum is used as the material for the heat-conducting structure 13, the cost and manufacturing difficulty of the heat-conducting structure 13 can be reduced.

[0052] Specifically, the aperture ratio of the piezoelectric structure 12 is 10% to 70%. The aperture ratio of the piezoelectric structure 12 refers to the ratio of the orthographic projection area of ​​the opening on the first electrode 11 in the piezoelectric element 10 to the sum of the orthographic projection areas of the piezoelectric structure 12 and the opening on the first electrode 11. That is, the ratio of the orthographic projection area of ​​the opening on the first electrode 11 to the area of ​​the closed shape enclosed by the orthographic projection of the side of the piezoelectric structure 12 away from the opening on the first electrode 11.

[0053] like Figure 3 As shown, the piezoelectric element 10 also includes a second electrode 14 disposed on the side of the piezoelectric structure 12 away from the first electrode 11, and the orthogonal projection of the second electrode 14 on the first electrode 11 is located within the orthogonal projection of the piezoelectric structure 12 on the first electrode 11.

[0054] A second electrode 14 is disposed on the side of the piezoelectric structure 12 away from the first electrode 11. The second electrode 14 refers to the top electrode of the piezoelectric element 10, and the orthographic projection of the second electrode 14 onto the first electrode 11 is also annular. The material of the second electrode 14 can also be a transparent conductive material, such as ITO, etc. Of course, the material of the second electrode 14 can also be a general metal material, such as Au, In, etc., and the thickness h1 of the first electrode 11 and the thickness h4 of the second electrode 14 can be equal.

[0055] In actual products, the orthographic projection of the second electrode 14 on the first electrode 11 can coincide with the orthographic projection of the piezoelectric structure 12 on the first electrode 11. However, due to the influence of the process, the orthographic projection area of ​​the second electrode 14 on the first electrode 11 will be smaller than the orthographic projection area of ​​the piezoelectric structure 12 on the first electrode 11. That is, the orthographic projection of the second electrode 14 on the first electrode 11 is located within the orthographic projection of the piezoelectric structure 12 on the first electrode 11. In this case, the second electrode 14 will not cover the opening of the piezoelectric structure 12.

[0056] In this embodiment, the thickness h2 of the thermally conductive structure 13 is less than or equal to the sum of the thicknesses of the piezoelectric structure 12 and the second electrode 14 along the direction perpendicular to the plane of the first electrode 11.

[0057] like Figure 3 As shown, the thickness of the piezoelectric structure 12 is h3, and the thickness of the second electrode 14 is h4, that is, the thickness h2 of the heat-conducting structure 13 is less than or equal to (h3+h4); and the thickness h2 of the heat-conducting structure 13 is greater than the thickness h3 of the piezoelectric structure 12.

[0058] By setting the thickness h2 of the heat-conducting structure 13 to be less than or equal to the sum of the thicknesses of the piezoelectric structure 12 and the second electrode 14, and by setting the thickness h2 of the heat-conducting structure 13 to be greater than the thickness h3 of the piezoelectric structure 12, the surface area of ​​the heat-conducting structure 13 can be increased. When the surface area of ​​the heat-conducting structure 13 increases, the heat dissipation effect of the heat-conducting structure 13 can be improved.

[0059] The thickness h2 of the thermally conductive structure 13 is 3 μm to 5 μm, the thickness h3 of the piezoelectric structure 12 is less than 5 μm, and the thickness h4 of the second electrode 14 is 100 nm to 1000 nm.

[0060] For example, the thickness h2 of the thermally conductive structure 13 can be set to 3.5 μm, the thickness h3 of the piezoelectric structure 12 can be set to 3 μm, and the thickness h4 of the second electrode 14 can be set to 600 nm, so that the thickness h2 of the thermally conductive structure 13 is less than or equal to the sum of the thicknesses of the piezoelectric structure 12 and the second electrode 14.

[0061] It should be noted that, according to testing, the piezoelectric element 10 of this application embodiment can significantly reduce the temperature rise caused by the vibration of the piezoelectric structure 12, with a temperature reduction of up to 50%, without affecting the performance of the piezoelectric element 10 itself.

[0062] In this embodiment, by forming a through opening in the piezoelectric structure, the area of ​​the piezoelectric structure in the piezoelectric element is reduced, thus reducing the heating area of ​​the piezoelectric structure during vibration and consequently reducing the heat generated by the piezoelectric structure. Furthermore, by adding a heat-conducting structure to the piezoelectric element, the heat generated by the piezoelectric structure during vibration is dissipated, improving the heat dissipation characteristics of the piezoelectric element. This avoids the problem of the piezoelectric structure being broken down due to excessive temperature and affecting the resonant frequency of the piezoelectric structure, thereby improving the reliability of the piezoelectric structure.

[0063] Reference Figure 4 The diagram shows a plan view of a piezoelectric vibrator according to an embodiment of this application. Figure 5 A cross-sectional view of a piezoelectric vibrator according to an embodiment of this application is shown. Figure 5 The sectional view shown is along Figure 4 The cross-sectional view shown is section B-B'.

[0064] This application embodiment also provides a piezoelectric vibrator, including a substrate 20 and at least one of the above-described piezoelectric elements 10 disposed on the substrate 20, wherein the thermal conductivity of the thermally conductive structure 13 is greater than the thermal conductivity of the substrate 20.

[0065] The substrate 20 can be a flexible substrate or a rigid substrate. For example, the flexible substrate can be made of PI (Polyimide), PET (Polyethylene Terephthalate), or PDMS (Polydimethylsiloxane), while the rigid substrate can be made of glass.

[0066] At least one piezoelectric element 10 is disposed on the substrate 20. Specifically, the substrate 20 is disposed on the side of the first electrode 11 away from the piezoelectric structure 12, that is, the substrate 20 is in direct contact with the first electrode 11 in the piezoelectric element 10.

[0067] If no heat-conducting structure 13 is provided in each piezoelectric element 10, the heat generated by the vibration of the piezoelectric structure 12 in the piezoelectric element 10 will be transferred to the substrate 20 through the first electrode 11, and heat dissipation will be achieved based on the substrate 20. However, the thermal conductivity of the substrate 20 itself is low. For example, the thermal conductivity of the glass substrate is only 1.22 W / (mK). If the heat dissipation effect of the substrate 20 is not good, it will lead to the accumulation of heat in the piezoelectric element 10, causing the temperature of the piezoelectric element 10 to rise.

[0068] In this embodiment, a heat-conducting structure 13 is added to each piezoelectric element 10. The heat generated by the vibration of the piezoelectric structure 12 in the piezoelectric element 10 is transferred to the heat-conducting structure 13 through the first electrode 11, or the heat is transferred to the substrate 20 through the first electrode 11 and then to the heat-conducting structure 13 through the substrate 20 and the first electrode 11. Since the thermal conductivity of the heat-conducting structure 13 is greater than that of the substrate 20, the heat dissipation effect of the heat-conducting structure 13 is better, thereby avoiding the accumulation of heat in the piezoelectric element 10 and preventing the temperature of the piezoelectric element 10 from becoming too high.

[0069] Furthermore, the piezoelectric vibrator also includes a first signal line connected to each first electrode 11 and a second signal line connected to each second electrode 14. The first signal line is used to provide a first driving signal to the first electrode 11, and the second signal line is used to provide a second driving signal to the second electrode 14. The first and second signal lines are made of conductive materials, such as metals or alloys.

[0070] It should be noted that for any two adjacent piezoelectric elements 10 in the piezoelectric vibrator, the first electrodes 11 and the second electrodes 14 are disconnected, so that the vibration of each piezoelectric element 10 can be controlled individually. Of course, the first electrodes 11 of all piezoelectric elements 10 in the piezoelectric vibrator can also be an integral structure, that is, the first electrodes 11 of all piezoelectric elements 10 in the piezoelectric vibrator are connected together. In this case, all piezoelectric elements 10 in the piezoelectric vibrator share the same first electrode 11, while the second electrodes 14 are still disconnected.

[0071] This application also provides an electronic device, including the piezoelectric vibrator described above.

[0072] In actual products, electronic devices can be display devices, which include a display panel and the aforementioned piezoelectric vibrator. The piezoelectric vibrator can be located on the light-emitting side of the display panel, so that the display device can simultaneously realize display function and tactile reproduction function.

[0073] In some embodiments, the display panel of the display device is an embedded touch display panel.

[0074] In some embodiments, the display device further includes a touch substrate between the display panel and the piezoelectric vibrator described above.

[0075] Of course, the electronic device in this application embodiment is not limited to a display device, and can also be any product or component with tactile reproduction function.

[0076] In this embodiment, by forming a through opening in the piezoelectric structure, the area of ​​the piezoelectric structure in the piezoelectric element is reduced, thus reducing the heating area of ​​the piezoelectric structure during vibration and consequently reducing the heat generated by the piezoelectric structure. Furthermore, by adding a heat-conducting structure to the piezoelectric element, the heat generated by the piezoelectric structure during vibration is dissipated, improving the heat dissipation characteristics of the piezoelectric element. This avoids the problem of the piezoelectric structure being broken down due to excessive temperature and affecting the resonant frequency of the piezoelectric structure, thereby improving the reliability of the piezoelectric structure.

[0077] Reference Figure 6 The flowchart illustrates a method for manufacturing a piezoelectric vibrator according to an embodiment of this application, which may specifically include the following steps:

[0078] Step 601: Form at least one first electrode on the substrate.

[0079] In the embodiments of this application, firstly, a substrate 20 is provided, which can be a flexible substrate or a rigid substrate. Then, at least one first electrode 11 is formed on the substrate 20 using a patterning process.

[0080] Specifically, a first electrode film is first deposited on the substrate 20, and the first electrode film is subjected to high-temperature annealing in a nitrogen atmosphere to reduce the resistivity of the first electrode film. Then, photoresist is coated on the first electrode film, and the photoresist is exposed and developed. Next, the first electrode film in the photoresist removal area is etched to remove the residual photoresist, thereby forming at least one first electrode 11 on the substrate 20. The material of the first electrode 11 can be ITO.

[0081] Step 602, forming a piezoelectric structure on each of the first electrodes; each piezoelectric structure having an opening that penetrates and exposes a portion of the first electrode along a direction perpendicular to the plane of the first electrode.

[0082] In this embodiment of the application, after forming at least one first electrode 11 on the substrate 20, a piezoelectric structure 12 is formed on each first electrode 11, and each piezoelectric structure 12 has an opening that penetrates and exposes a portion of the first electrode 11 in a direction perpendicular to the plane where the first electrode 11 is located, and the opening ratio of the piezoelectric structure 12 is 10% to 70%.

[0083] Specifically, step 602 includes sub-steps S6021, S6022, and S6023:

[0084] Sub-step S6021: Forming a piezoelectric thin film covering the first electrode and the substrate;

[0085] Sub-step S6022 involves subjecting the piezoelectric thin film to high-temperature annealing and laser annealing.

[0086] Sub-step S6023 involves patterning the piezoelectric thin film to form a piezoelectric structure on each of the first electrodes.

[0087] Optionally, after forming at least one first electrode 11 on the substrate 20, a piezoelectric thin film covering the first electrode 11 and the substrate 20 is first formed using dry deposition or sol-gel method. Next, the structure with the formed piezoelectric thin film is placed in an air environment at 550°C to 600°C for RTA (Rapid Thermal Annealing) treatment. During the high-temperature annealing treatment, the piezoelectric thin film is irradiated with a laser to achieve laser annealing treatment of the piezoelectric thin film. By performing high-temperature annealing treatment and laser annealing treatment on the piezoelectric thin film, the grain size and crystallinity of the piezoelectric thin film are improved, thereby reducing the dielectric loss of the piezoelectric thin film. Finally, photoresist is coated on the piezoelectric thin film after high-temperature annealing treatment and laser annealing treatment. The photoresist is exposed and developed. Then, the piezoelectric thin film in the photoresist removal area is etched to remove the residual photoresist, thereby realizing the formation of a piezoelectric structure 12 on each first electrode 11.

[0088] Experimental testing revealed that X-ray diffraction of piezoelectric structures formed under different conditions yielded results such as... Figure 7 The XRD (X-ray diffraction) pattern shown has the X-ray diffraction angle 2θ on the horizontal axis and the diffraction intensity on the vertical axis.

[0089] Figure 7 The results include three diffraction curves: one for a piezoelectric structure obtained by high-temperature annealing (e.g., 550°C), another for a piezoelectric structure obtained by high-temperature annealing (e.g., 550°C) followed by laser irradiation for 30 seconds, and a third for a piezoelectric structure obtained by high-temperature annealing (e.g., 550°C) followed by laser irradiation for 60 seconds. It can be seen that each of these three diffraction curves has two diffraction peaks: one along the crystal plane (100) and the other along the crystal plane (110).

[0090] Analysis shows that when a piezoelectric structure is obtained using only high-temperature annealing, the ratio of diffraction intensity along crystal plane (110) to diffraction intensity along crystal plane (100) is 10:1, and the grain size of the piezoelectric structure is greater than or equal to 20 nm and less than 30 nm. However, when a piezoelectric structure is obtained using both high-temperature annealing and laser irradiation, the ratio of diffraction intensity along crystal plane (110) to diffraction intensity along crystal plane (100) is greater than 20:1, and the grain size of the piezoelectric structure is 30 nm to 50 nm. Therefore, in this embodiment, the piezoelectric structure 12 is fabricated using high-temperature annealing and laser annealing, which can improve the grain size and crystallinity of the piezoelectric structure 12. When the grain size and crystallinity are improved, the dielectric loss of the piezoelectric structure 12 can be further reduced. Tests show that the dielectric loss factor can be reduced to below 0.01, and further reduced to below 0.005.

[0091] It should be noted that, Figure 7 The diffraction peaks of Pt (platinum) are mainly used as reference crystal planes to determine the actual diffraction intensity of the piezoelectric structure along crystal plane (110) and along crystal plane (100). No film layer of material Pt is provided in the piezoelectric element 10.

[0092] Furthermore, the laser annealing process can be carried out during high-temperature annealing, that is, by irradiating the piezoelectric film with a laser in a high-temperature annealing environment. Of course, the laser annealing process can also be carried out after the high-temperature annealing is completed and cooled down. However, when the piezoelectric film is treated with both high-temperature annealing and laser annealing, the performance of the resulting piezoelectric structure 12 will be better.

[0093] When processing piezoelectric films using a high-temperature annealing process, the temperature is between 550°C and 600°C. If the high-temperature annealing temperature exceeds 600°C, the substrate 20 is prone to deformation. Therefore, this embodiment of the application can prevent the substrate 20 from deforming due to high temperature by reasonably controlling the high-temperature annealing temperature. When processing piezoelectric films using a laser annealing process, the duration of laser irradiation is related to factors such as laser intensity and the thickness of the piezoelectric film. This embodiment of the application does not impose any restrictions on these factors.

[0094] Step 603: A heat-conducting structure is formed in each of the openings; the orthographic projection of the heat-conducting structure on the first electrode and the orthographic projection of the piezoelectric structure on the first electrode do not overlap.

[0095] In this embodiment of the application, after forming a piezoelectric structure 12 on each first electrode 11, a heat-conducting structure 13 is formed in the opening of each piezoelectric structure 12, and the orthographic projection of the heat-conducting structure 13 on the first electrode 11 and the orthographic projection of the piezoelectric structure 12 on the first electrode 11 do not overlap.

[0096] Specifically, a thermally conductive film covering the piezoelectric structure 12, the first electrode 11, and the substrate 20 is first formed. Photoresist is then coated on the thermally conductive film, and the photoresist is exposed and developed. Next, the thermally conductive film in the photoresist removal area is etched, and the residual photoresist is removed, thereby forming a thermally conductive structure 13 within the opening of each piezoelectric structure 12.

[0097] Optionally, after step 603, the method further includes: forming a second electrode on the side of each piezoelectric structure away from the first electrode; the orthographic projection of the second electrode onto the first electrode lies within the orthographic projection of the piezoelectric structure onto the first electrode.

[0098] After forming a heat-conducting structure 13 within the opening of each piezoelectric structure 12, a second electrode film is first formed covering the heat-conducting structure 13, the piezoelectric structure 12, the first electrode 11, and the substrate 20. Then, photoresist is coated on the second electrode film, and the photoresist is exposed and developed. Next, the second electrode film in the photoresist removal area is etched, and the residual photoresist is removed, thereby forming a second electrode 14 on the side of each piezoelectric structure 12 away from the first electrode 11. The orthographic projection of the second electrode 14 on the first electrode 11 is located within the orthographic projection of the piezoelectric structure 12 on the first electrode 11. The material of the second electrode 14 is also ITO.

[0099] Subsequently, the piezoelectric element 10 needs to be polarized to improve the piezoelectric constant of the piezoelectric structure 12 in the piezoelectric element 10, so that the piezoelectric element 10 has good piezoelectric characteristics.

[0100] In this embodiment, by forming a through opening in the piezoelectric structure, the area of ​​the piezoelectric structure in the piezoelectric element is reduced, thus reducing the heating area of ​​the piezoelectric structure during vibration and consequently reducing the heat generated by the piezoelectric structure. Furthermore, by adding a heat-conducting structure to the piezoelectric element, the heat generated by the piezoelectric structure during vibration is dissipated, improving the heat dissipation characteristics of the piezoelectric element. This avoids the problem of the piezoelectric structure being broken down due to excessive temperature and affecting the resonant frequency of the piezoelectric structure, thereby improving the reliability of the piezoelectric structure.

[0101] This application also provides a driving method for a piezoelectric vibrator, applicable to driving such... Figure 4 and Figure 5 The piezoelectric vibrator shown, the method includes:

[0102] Step S01: Input a first driving signal to the first electrode in the piezoelectric element and input a second driving signal to the second electrode in the piezoelectric element; wherein, the second driving signal is divided into a first stage and a second stage, the second driving signal in the first stage is a pulse signal, and the voltage of the second driving signal in the second stage is a preset voltage; the voltage of the first driving signal is also the preset voltage.

[0103] In the actual product, the first electrode 11 in each piezoelectric element 10 is connected to the first signal line, and the second electrode 14 in each piezoelectric element 10 is connected to the second signal line. When it is necessary to control the vibration of the piezoelectric structure 12 in any one or more piezoelectric elements 10, a first driving signal is input to the first electrode 11 in the corresponding piezoelectric element 10 through the first signal line, and a second driving signal is input to the second electrode 14 in the corresponding piezoelectric element 10 through the second signal line.

[0104] Furthermore, the second driving signal is divided into multiple cycles, and each cycle is divided into a first stage and a second stage. The second driving signal in the first stage is a pulse signal with a frequency greater than 500Hz. The voltage of the second driving signal in the second stage is a preset voltage, and the voltage of the first driving signal is the same preset voltage in each stage.

[0105] The preset voltage can be 0V. That is, in the first stage, the second driving signal is a pulse signal, which causes a pressure difference between the first electrode 11 and the second electrode 14 on both sides of the piezoelectric structure 12 to generate an electric field, and the piezoelectric structure 12 vibrates under this electric field. In the second stage, the voltages of the first driving signal and the second driving signal are both 0V, so there is no pressure difference between the first electrode 11 and the second electrode 14, and the piezoelectric structure 12 does not vibrate at this time.

[0106] In actual products, the first electrode 11 can be grounded through the first signal line, or the first signal line can continuously input a low voltage signal to the first electrode 11.

[0107] In this embodiment, the driving method of the piezoelectric element 10 is changed from continuous driving to duty-cycle driving. That is, the piezoelectric structure 12 is controlled to vibrate in the first stage of a cycle, and the piezoelectric structure 12 is controlled not to vibrate in the second stage of the same cycle. The piezoelectric structure 12 is controlled to vibrate again in the first stage of the next cycle.

[0108] When the driving mode of the piezoelectric element 10 is changed to duty mode, the power consumption of the piezoelectric element 10 can be reduced, and the heat generated by the piezoelectric structure 12 can be further reduced.

[0109] The ratio between the duration of the first stage and the duration of the second stage is 1:1 to 1:10, such as setting the ratio between the duration of the first stage and the duration of the second stage to 2:1 or 3:1, etc.

[0110] By reasonably setting the input duration of the pulse signal and the preset voltage in the second driving signal, the power consumption of the piezoelectric element 10 can be reduced without affecting the user's actual tactile effect, and the heat generated by the piezoelectric structure 12 can be further reduced.

[0111] In this embodiment, by forming a through opening in the piezoelectric structure, the area of ​​the piezoelectric structure in the piezoelectric element is reduced, thus reducing the heating area of ​​the piezoelectric structure during vibration and consequently reducing the heat generated by the piezoelectric structure. Furthermore, by adding a heat-conducting structure to the piezoelectric element, the heat generated by the piezoelectric structure during vibration is dissipated, improving the heat dissipation characteristics of the piezoelectric element. This avoids the problem of the piezoelectric structure being broken down due to excessive temperature and affecting the resonant frequency of the piezoelectric structure, thereby improving the reliability of the piezoelectric structure.

[0112] The terms "an embodiment," "embodiment," or "one or more embodiments" as used herein mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this application. Furthermore, please note that the examples of the phrase "in one embodiment" do not necessarily all refer to the same embodiment.

[0113] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0114] In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A piezoelectric element, characterized in that, The piezoelectric element comprises: a first electrode and a piezoelectric structure disposed on the first electrode, the piezoelectric structure having an opening exposing part of the first electrode in a direction perpendicular to a plane on which the first electrode lies; wherein the piezoelectric structure is made by high-temperature annealing and laser annealing; the piezoelectric element further comprises a heat-conducting structure disposed in the opening, and a projection of the heat-conducting structure on the first electrode does not overlap with a projection of the piezoelectric structure on the first electrode; the piezoelectric element further comprises a second electrode disposed on a side of the piezoelectric structure away from the first electrode, and a thickness of the heat-conducting structure is less than or equal to a sum of thicknesses of the piezoelectric structure and the second electrode in the direction perpendicular to the plane on which the first electrode lies.

2. The piezoelectric element according to claim 1, characterized by An opening rate of the piezoelectric structure is 10% to 70%.

3. The piezoelectric element according to claim 1, characterized by A projection of the second electrode on the first electrode is located within a projection of the piezoelectric structure on the first electrode.

4. The piezoelectric element according to claim 1, characterized by The thickness of the heat-conducting structure is 3 μm to 5 μm, the thickness of the piezoelectric structure is less than 5 μm, and the thickness of the second electrode is 100 nm to 1000 nm.

5. The piezoelectric element according to claim 1, characterized by The heat-conducting structure is made of a heat-conducting metal.

6. A piezoelectric vibrator characterized by comprising: The piezoelectric element comprises a substrate and at least one piezoelectric element as claimed in any one of claims 1 to 5, and a thermal conductivity of the heat-conducting structure is greater than a thermal conductivity of the substrate.

7. A method of manufacturing a piezoelectric vibrator, characterized by comprising: The piezoelectric element comprises: forming at least one first electrode on a substrate; forming a piezoelectric structure on each of the first electrodes; each of the piezoelectric structures has an opening exposing part of the first electrode in a direction perpendicular to a plane on which the first electrode lies; wherein the piezoelectric structure is made by high-temperature annealing and laser annealing; forming a heat-conducting structure in each of the openings; a projection of the heat-conducting structure on the first electrode does not overlap with a projection of the piezoelectric structure on the first electrode; forming a second electrode on a side of each of the piezoelectric structures away from the first electrode, and a thickness of the heat-conducting structure is less than or equal to a sum of thicknesses of the piezoelectric structure and the second electrode in the direction perpendicular to the plane on which the first electrode lies.

8. The method of claim 7, wherein, The step of forming a piezoelectric structure on each of the first electrodes comprises: forming a piezoelectric film covering the first electrodes and the substrate; performing high-temperature annealing and laser annealing on the piezoelectric film; performing a patterning process on the piezoelectric film to form a piezoelectric structure on each of the first electrodes.

9. The method of claim 7, wherein, After the step of forming a heat-conducting structure in each of the openings, the method further comprises: forming a second electrode on a side of each of the piezoelectric structures away from the first electrode; a projection of the second electrode on the first electrode is located within a projection of the piezoelectric structure on the first electrode.

10. A driving method of a piezoelectric vibrator, characterized by, The method for driving a piezoelectric vibrator as claimed in claim 7 comprises: inputting a first driving signal to a first electrode in the piezoelectric element and inputting a second driving signal to a second electrode in the piezoelectric element; The second driving signal is divided into a first stage and a second stage, the second driving signal in the first stage is a pulse signal, and the voltage of the second driving signal in the second stage is a preset voltage; the voltage of the first driving signal is also the preset voltage.

11. The method of claim 10, wherein, The ratio between the duration of the first stage and the duration of the second stage is 1:1 to 1:

10.

12. An electronic device, comprising: The piezoelectric vibrator as claimed in claim 6.

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