Piezoelectric sensor, piezoelectric ceramic apparatus and electronic device

Abstract

Provided in the present application are a piezoelectric sensor, a piezoelectric ceramic apparatus and an electronic device. The piezoelectric sensor comprises a first piezoelectric ceramic, a conductive member and a second piezoelectric ceramic, wherein the first piezoelectric ceramic and the second piezoelectric ceramic are both connected to the conductive member, and the polarization directions of the first piezoelectric ceramic and the second piezoelectric ceramic in a first direction are opposite. The piezoelectric sensor enables electrical signals, which are generated by the first piezoelectric ceramic and the second piezoelectric ceramic due to temperature changes, to cancel each other, so as to ensure the detection reliability and detection accuracy of the piezoelectric sensor, thereby ensuring the measurement sensitivity and measurement accuracy of a subsequent-stage circuit for measuring a quasi-static force.

Description

Piezoelectric sensors, piezoelectric ceramic devices and electronic equipment

[0001] Related applications

[0002] This application claims priority to the following Chinese patent application: Chinese patent application No. 202411509560X, filed on October 28, 2024, entitled "Piezoelectric Sensor, Piezoelectric Ceramic Device and Electronic Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of force measurement technology, and more specifically, to a piezoelectric sensor, a piezoelectric ceramic device, and an electronic device. Background Technology

[0004] In some electronic devices, touchpads are usually configured as interactive input devices to interact with users. Among them, piezoelectric sensors are the core sensor components in touchpads, which can detect changes in pressure applied by the user to the touchpad surface to achieve force-sensitive input.

[0005] However, the piezoelectric ceramic in a piezoelectric sensor may experience temperature drift due to temperature variations, which can affect the sensor's detection performance and measurement accuracy. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a piezoelectric sensor, a piezoelectric ceramic device, and an electronic device, aiming to resolve the problem that piezoelectric ceramics may experience temperature drift due to temperature variations, which in turn affects the detection performance and measurement accuracy of the piezoelectric sensor.

[0007] In a first aspect, this application provides a piezoelectric sensor, which includes a first piezoelectric ceramic, a conductive element, and a second piezoelectric ceramic; the first piezoelectric ceramic and the second piezoelectric ceramic are respectively connected to the conductive element, and the polarization directions of the first piezoelectric ceramic and the second piezoelectric ceramic are opposite in a first direction.

[0008] Based on the piezoelectric sensor of this application embodiment, when the piezoelectric sensor is not subjected to force, since the polarization directions of the first and second piezoelectric ceramics are opposite in the first direction, the electrical signals generated by the temperature changes of the first and second piezoelectric ceramics can cancel each other out. This avoids the problem that temperature drift in the piezoelectric ceramics could cause the piezoelectric sensor to release charge when not under force, affecting the detection effect and measurement accuracy of the piezoelectric sensor, and consequently causing the test baseline in the subsequent circuit (e.g., the piezoelectric ceramic static force detection system) to drift, affecting the measurement sensitivity of quasi-static force. Thus, by canceling out the electrical signals generated by the temperature changes of the first and second piezoelectric ceramics, the detection reliability and accuracy of the piezoelectric sensor can be guaranteed, thereby ensuring the measurement sensitivity and accuracy of the subsequent circuit in measuring quasi-static force. When the piezoelectric sensor is subjected to a force in the first direction, the first piezoelectric ceramic generates a corresponding charge based on the pressure it receives and transfers the charge to the charge amplifier in the subsequent circuit. At the same time, the second piezoelectric ceramic also generates a corresponding charge based on the pressure it receives and transfers the charge to the charge amplifier in the subsequent circuit. That is, the charge received by the charge amplifier at this time contains dual signals. The charge amplifier can perform detection based on these dual signals, which improves the detection reliability of the piezoelectric sensor and thus ensures the measurement sensitivity and accuracy of the subsequent circuit in measuring quasi-static force.

[0009] In one possible implementation, the first piezoelectric ceramic and the second piezoelectric ceramic are respectively bonded to the two opposite sides of the conductive element in a first direction.

[0010] In this implementation, the charges generated by the pyroelectric effect of the first and second piezoelectric ceramics are in opposite directions. Thus, there is no potential difference or charge flow between the first and second output signal lines, allowing the electrical signals generated by the temperature changes of the first and second piezoelectric ceramics to cancel each other out. This ensures the reliability and accuracy of the piezoelectric sensor, thereby guaranteeing the sensitivity and accuracy of the subsequent circuitry in measuring quasi-static forces. Simultaneously, when the first and second piezoelectric ceramics are subjected to external forces (such as pressure or vibration), the voltages generated by them are in the same direction. This allows the useful signals generated by the first and second piezoelectric ceramics to be superimposed, improving the accuracy of the piezoelectric sensor and enhancing the resistance to temperature drift when the subsequent circuitry measures quasi-static force signals.

[0011] In one possible implementation, the piezoelectric sensor further includes a heat-conducting element located between and connected to the first piezoelectric ceramic and the conductive element; or, the heat-conducting element located between and connected to the second piezoelectric ceramic and the conductive element.

[0012] In this implementation, the heat-conducting component can make the temperature of the environment where the first piezoelectric ceramic and the second piezoelectric ceramic are located the same through heat conduction, so that the heat can be evenly distributed, and thus the electrical signals generated by the two due to temperature changes are the same. This avoids the problem that the electrical signals generated by the first piezoelectric ceramic and the second piezoelectric ceramic due to temperature changes cannot completely cancel each other out, ensuring the detection accuracy and reliability of the piezoelectric sensor, and thus ensuring the measurement sensitivity and accuracy of the subsequent circuit for measuring the quasi-static force signal.

[0013] In one possible implementation, the material of the heat-conducting component includes any one of conductive copper foil, thermal conductive gel, and ceramic material.

[0014] In one possible implementation, the first piezoelectric ceramic and the second piezoelectric ceramic are disposed adjacent to each other on one side of the conductive element along a second direction; wherein the first direction intersects the second direction.

[0015] In this implementation, since the first piezoelectric ceramic and the second piezoelectric ceramic are on the same surface and at the same temperature, the number of electrical signals generated by the first piezoelectric ceramic and the second piezoelectric ceramic due to the pyroelectric effect is more consistent, which further improves the anti-temperature drift performance of the piezoelectric sensor, thereby further improving the detection reliability of the piezoelectric sensor, and thus improving the measurement sensitivity and measurement accuracy of the subsequent circuit for measuring quasi-static force.

[0016] In one possible implementation, the conductive component is made of any one of copper alloy, nickel alloy, iron alloy, titanium alloy, and conductive fiberglass board.

[0017] Secondly, this application provides a piezoelectric ceramic device, including a piezoelectric sensor as described in any of the optional embodiments of the first aspect and a fixing structure, wherein the fixing structure is fixedly connected to at least one end of the piezoelectric sensor.

[0018] In one possible implementation, the fixed structure includes a cantilever beam, which is fixedly connected to at least one end of the piezoelectric sensor along a second direction.

[0019] In this implementation, the piezoelectric sensor can be firmly fixed to the housing or other structure of the electronic device by setting a cantilever beam at only one end. At the same time, since the other end of the piezoelectric sensor is unsupported, it provides a larger deformation space for the piezoelectric sensor. The design is simple and the manufacturing cost is low.

[0020] In one possible implementation, the fixing structure includes two simply supported beams, which are respectively fixedly connected to the two ends of the piezoelectric sensor along the second direction.

[0021] In this implementation, the piezoelectric sensor is fixed to the housing or other structure of the electronic device using two simply supported beams, which improves the fixation stability and thus ensures the detection reliability of the piezoelectric sensor. Secondly, compared to cantilever beams, simply supported beams have a simpler structure and lower manufacturing cost, and the simply supported beams at both ends of the piezoelectric sensor improve the overall rigidity of the piezoelectric ceramic device.

[0022] Thirdly, this application provides an electronic device including the piezoelectric ceramic device described in any alternative manner of the second aspect. Attached Figure Description

[0023] 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 only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 is a schematic diagram of the structure of a piezoelectric sensor provided in a related technical embodiment;

[0025] Figure 2 is a schematic diagram of the structure of a piezoelectric ceramic device provided in an embodiment of this application;

[0026] Figure 3 is a schematic diagram of another piezoelectric ceramic device provided in an embodiment of this application;

[0027] Figure 4 is a side view of a piezoelectric sensor provided in an embodiment of this application;

[0028] Figure 5 is a side view of another piezoelectric sensor provided in an embodiment of this application;

[0029] Figure 6 is a side view of a piezoelectric ceramic device provided in an embodiment of this application.

[0030] Figure 7 is a side view of another piezoelectric sensor provided in an embodiment of this application;

[0031] Figure 8 is a side view of another piezoelectric sensor provided in an embodiment of this application;

[0032] Figure 9 is a side view of another piezoelectric sensor provided in an embodiment of this application;

[0033] Figure 10 is a side view of another piezoelectric ceramic device provided in an embodiment of this application.

[0034] Figure label:

[0035] 1' Piezoelectric sensor; 11' Copper sheet; 12' Electrode; 13' Piezoelectric ceramic; 1, Piezoelectric sensor; 1A, Force point; 11, First piezoelectric ceramic; 11A, First output signal line; 12, Conductive component; 13, Second piezoelectric ceramic; 13A, Second output signal line; 2, Fixed structure; 21, Cantilever beam; 22, Simply supported beam; 23, Clamping component; +, Positive voltage; -, Negative voltage; f1, Tension force; f2, Contraction force.

[0036] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Embodiments of the present invention

[0037] 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 a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0038] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0039] Furthermore, the use of terms such as "first," "second," etc., in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0040] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0041] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

[0042] In many electronic devices, such as laptops, tablets, 2-in-1 laptops / detachable tablets, all-in-one computers, professional graphics input devices, and smart displays, touchpads are commonly used as interactive input devices for user interaction. Piezoelectric sensors are the core sensor components in touchpads, capable of detecting changes in pressure applied by the user to the touchpad surface to achieve force-sensing input. Specifically, a piezoelectric sensor is a sensor based on the piezoelectric effect. Its sensitive element is typically made of piezoelectric materials (such as piezoelectric ceramics). When a force is applied to the piezoelectric material, a charge is generated on its surface. This charge can be detected and converted into a voltage output by a piezoelectric ceramic static force detection system composed of a charge amplifier.

[0043] As shown in Figure 1, the piezoelectric sensor 1' in related technologies typically consists of a copper sheet 11', an electrode 12', and a piezoelectric ceramic 13'. The piezoelectric ceramic 13' converts mechanical energy (i.e., pressure) into electrical energy. The copper sheet 11' is typically used to reinforce the structure or as part of the lead-out electrode. The electrode 12' is usually directly attached to the surface of the piezoelectric ceramic 13' to collect the generated charge or apply a voltage to cause deformation of the piezoelectric ceramic 13'. When the piezoelectric ceramic 13' is in a compressed state (pressed state), positive charges accumulate on both the upper and lower surfaces to generate a positive voltage. Conversely, when the piezoelectric ceramic 13' is in a stretched state (released state), it generates the opposite voltage; that is, negative charges accumulate on both the upper and lower surfaces to generate a negative voltage. In other words, in the pressed state, the piezoelectric sensor 1' can only generate a positive voltage, while in the released state, it generates a negative voltage, causing the current voltage to return to zero. Furthermore, according to the theory of action and reaction forces, the force during the pressing process is equal to the force during the releasing process. Therefore, the absolute values ​​of the charges generated during pressing and releasing are equal, but their directions are opposite. Thus, when the piezoelectric ceramic 13' is in a compressed or stretched state, the charge it generates will be detected by the piezoelectric ceramic static force detection system composed of a charge amplifier and converted into a voltage output to obtain a quasi-static force signal.

[0044] However, the piezoelectric ceramic 13' in the piezoelectric sensor 1' is easily affected by temperature. That is, when the temperature of the environment in which the piezoelectric sensor 1' is located changes, due to the pyroelectric phenomenon of the piezoelectric ceramic 13', the cell inside the piezoelectric ceramic 13' will deflect and release charge. At this time, the piezoelectric sensor 1' is not under force, but charge will still accumulate on the surface of the piezoelectric ceramic 13'. That is, the piezoelectric sensor 1' will release charge, which affects the detection effect and measurement accuracy of the piezoelectric sensor 1'. When the charge amplifier accumulates a lot of charge, it will cause the test baseline of the piezoelectric ceramic static force detection system it constitutes to drift, thereby affecting the measurement sensitivity of quasi-static force.

[0045] Therefore, this application provides a piezoelectric sensor, a piezoelectric ceramic device, and an electronic device. This piezoelectric sensor enables the electrical signals generated by the temperature changes of the first and second piezoelectric ceramics to cancel each other out, thereby ensuring the reliability and accuracy of the piezoelectric sensor's detection, and consequently ensuring the sensitivity and accuracy of the subsequent circuitry in measuring quasi-static forces.

[0046] The piezoelectric sensor, piezoelectric ceramic device, and electronic device provided in this application are described below with reference to the accompanying drawings.

[0047] This application provides an electronic device equipped with a piezoelectric ceramic device, which serves as an interactive input device to interact with the user and meet different user needs. The electronic device in this application can also be a laptop, tablet, 2-in-1 laptop / detachable tablet, all-in-one computer, professional graphics input device, smart display, or other electronic devices requiring touch functionality; therefore, this application does not impose specific limitations.

[0048] For example, when the electronic device in this application is a stylus, the piezoelectric ceramic device contacts the pen tip structure to detect changes in pressure applied by the user to the surface of the piezoelectric ceramic device, thereby achieving force-sensing input and detecting writing force. Furthermore, both ends of the piezoelectric ceramic device can be fixed within the stylus's housing using clamps to improve the stability of the piezoelectric ceramic device within the stylus. Secondly, the piezoelectric ceramic device can also be electrically connected to the main control module within the stylus via the clamps to transmit the detected signals to the main control module.

[0049] To enable force-sensing input in piezoelectric ceramic devices within electronic devices, as shown in Figure 2, one example includes a piezoelectric sensor 1. The piezoelectric sensor 1 detects changes in pressure applied by the user to the touchpad surface, thus achieving force-sensing input. To further enhance the robustness of the piezoelectric sensor 1's attachment to the electronic device, as shown in Figure 2, the piezoelectric ceramic device also includes a fixing structure 2. The fixing structure 2 is fixedly connected to at least one end of the piezoelectric sensor 1, securing the piezoelectric sensor 1 to the housing or other structure of the electronic device. This ensures the robustness and stability of the connection of the piezoelectric sensor 1 within the electronic device, thereby guaranteeing the reliability of its detection capabilities.

[0050] Optionally, as shown in Figure 2, the fixing structure 2 may include a cantilever beam 21, which is fixedly connected to at least one end of the piezoelectric sensor 1 along the second direction BB. The cantilever beam 21 may also be fixedly connected to the housing or other structure of the electronic device to fix the piezoelectric sensor 1 to the housing or other structure of the electronic device. In this example, the force point 1A of the piezoelectric sensor 1 is located as shown in Figure 2, that is, the force point 1A is close to the end where the cantilever beam 21 is not provided. Thus, by providing the cantilever beam 21 at only one end, the piezoelectric sensor 1 can be firmly fixed to the housing or other structure of the electronic device. At the same time, since the other end of the piezoelectric sensor 1 is unsupported, it provides a larger deformation space for the piezoelectric sensor 1, and the design is simple and the manufacturing cost is low.

[0051] To further improve the robustness of the piezoelectric sensor 1 fixed to the housing or other structure of the electronic device, optionally, as shown in Figure 3, the fixing structure 2 may include two simply supported beams 22. The two simply supported beams 22 are respectively fixedly connected to both ends of the piezoelectric sensor 1 along the second direction BB. In this example, the force point 1A of the piezoelectric sensor 1 is located at the position shown in Figure 3, that is, the force point 1A is located in the middle of the piezoelectric sensor 1. Thus, fixing the piezoelectric sensor 1 to the housing or other structure of the electronic device through the two simply supported beams 22 improves the fixing robustness, thereby ensuring the detection reliability of the piezoelectric sensor 1. Secondly, compared to the cantilever beam 21, the simply supported beam 22 has a simpler structure and lower manufacturing cost, and the simply supported beams 22 located at both ends of the piezoelectric sensor 1 improve the overall rigidity of the piezoelectric ceramic device.

[0052] Optionally, as shown in Figure 4, the fixing structure 2 can also be a clamping member 23. The clamping member 23 is fixed to the housing of the electronic device, and the opening of the clamping member 23 abuts against both sides of the piezoelectric sensor 1 along the first direction AA to clamp and fix the piezoelectric sensor 1 inside the housing of the electronic device, thereby ensuring the strong connection between the piezoelectric sensor 1 and the electronic device. Two clamping members 23 can also be provided, with each clamping member 23 adjacent to both ends of the piezoelectric sensor 1 along the second direction BB. One clamping member abuts against both sides of the piezoelectric sensor 1 along the first direction AA, and the other clamping member has a certain gap between it and the two sides of the piezoelectric sensor 1 along the first direction AA; or, both clamping members abut against both sides of the piezoelectric sensor 1 along the first direction AA. The fixing structure 2 can also be other structures capable of achieving the above functions, and this application does not impose specific limitations on these.

[0053] It is worth noting here that the first direction AA intersects with the second direction BB; that is, when the first direction AA is perpendicular, the second direction BB is a horizontal direction intersecting with it, and vice versa. The piezoelectric ceramic device provided in this application typically also includes a charge amplifier, a piezoelectric ceramic static force detection system composed of the charge amplifier, and other circuits or systems. This application does not impose specific limitations on these aspects.

[0054] The piezoelectric sensor 1 typically incorporates a piezoelectric ceramic. When the piezoelectric material is subjected to force, a charge is generated on its surface. This charge can be detected and converted into a voltage output by a subsequent circuit (e.g., a piezoelectric ceramic static force detection system composed of a charge amplifier). To avoid the potential temperature drift of the piezoelectric ceramic due to temperature influences, which could affect the detection effect and measurement accuracy of the piezoelectric sensor 1, in one example, as shown in Figures 5 to 7, the piezoelectric sensor 1 provided in this application may include a first piezoelectric ceramic 11, a conductive element 12, and a second piezoelectric ceramic 13. The first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are respectively connected to the conductive element 12, and the polarization directions of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are opposite in the first direction AA. As shown in Figure 5, assuming that the polarization direction of the first piezoelectric ceramic 11 is downward along the first direction AA, that is, the voltage on the side of the first piezoelectric ceramic 11 facing the conductive element 12 is a negative voltage - and the voltage on the side of the first piezoelectric ceramic 11 away from the conductive element 12 is a positive voltage +, then at this time, the polarization direction of the second piezoelectric ceramic 13 is upward along the first direction AA, that is, the voltage on the side of the second piezoelectric ceramic 13 facing the conductive element 12 is a negative voltage - and the voltage on the side of the second piezoelectric ceramic 13 away from the conductive element 12 is a positive voltage +.

[0055] Here, it can be understood that when the piezoelectric sensor 1 includes a first piezoelectric ceramic 11 and a second piezoelectric ceramic 13, the two signal output signal lines of the piezoelectric sensor 1 can be the first output signal line 11A of the first piezoelectric ceramic 11 and the second output signal line 13A of the second piezoelectric ceramic 13, respectively. The first output signal line 11A and the second output signal line 13A are respectively connected to the charge amplifier in the subsequent circuit to realize signal transmission.

[0056] In this example, when the piezoelectric sensor 1 is not under force, since the polarization directions of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are opposite in the first direction AA, the electrical signals generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 due to temperature changes (e.g., increased temperature) can cancel each other out. This avoids the piezoelectric ceramics from releasing charge when not under force due to temperature drift, which would affect the detection effect and measurement accuracy of the piezoelectric sensor 1, and consequently cause the test baseline in the subsequent circuit (e.g., the piezoelectric ceramic static force detection system) to drift, affecting the measurement sensitivity of the quasi-static force. Thus, by canceling out the electrical signals generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 due to temperature changes, the detection reliability and accuracy of the piezoelectric sensor 1 can be guaranteed, thereby ensuring the measurement sensitivity and accuracy of the subsequent circuit in measuring the quasi-static force. When the piezoelectric sensor 1 is subjected to a force in the first direction AA, the first piezoelectric ceramic 11 generates a corresponding charge based on the pressure it bears and transfers the charge to the charge amplifier in the subsequent circuit. The second piezoelectric ceramic 13 generates a corresponding charge based on the pressure it bears and transfers the charge to the charge amplifier in the subsequent circuit. That is, the charge received by the charge amplifier at this time contains dual signals. The charge amplifier can perform detection based on these dual signals, which improves the detection reliability of the piezoelectric sensor 1 and thus ensures the measurement sensitivity and accuracy of the subsequent circuit in measuring quasi-static force.

[0057] To ensure that the electrical signals generated by the temperature changes of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 cancel each other out, in one example, referring to Figures 5 and 6, the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are respectively attached to opposite sides of the conductive element 12 along the first direction AA. In this example, when there is a temperature change in the piezoelectric sensor 1, since the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are located on opposite sides of the conductive element 12 along the first direction AA, and the polarization directions of the upper and lower piezoelectric ceramics are opposite, the charges generated by the pyroelectric discharge of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are opposite in direction. Thus, there is no potential difference between the first output signal line 11A and the second output signal line 13A, i.e., no charge flow, thereby achieving the purpose of canceling out the electrical signals generated by the temperature changes of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13. This ensures the detection reliability and accuracy of the piezoelectric sensor 1, and further ensures the measurement sensitivity and accuracy of the subsequent circuit for measuring quasi-static force. Meanwhile, when the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are subjected to external force (such as pressure or vibration), the voltage generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 is in the same direction, so that the useful signals generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 can be superimposed, thereby improving the detection accuracy of the piezoelectric sensor 1 and thus improving the ability of the subsequent circuit to resist temperature drift when measuring quasi-static force signals.

[0058] For example, as shown in Figure 6, taking the cantilever beam 21 as an example of the fixed structure 2, assuming that the pressure on the piezoelectric sensor 1 is vertically downward in the first direction AA (i.e., the bending deformation is downward), the piezoelectric sensor 1 will bend due to the external force. At this time, the first piezoelectric ceramic 11 is in a tensile state, that is, the force on the first piezoelectric ceramic 11 is the stretching force f1, and the second piezoelectric ceramic 13 is in a compressed state, that is, the force on the second piezoelectric ceramic 13 is the contraction force f2. The voltages generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are in the same direction, so that the useful signals generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 can be superimposed to improve the detection accuracy of the piezoelectric sensor 1, and thus improve the ability of the subsequent circuit to resist temperature drift when measuring the quasi-static force signal.

[0059] In this example, when the temperature of the environment where the piezoelectric sensor 1 is located is not uniform, that is, the temperature of the environment where the first piezoelectric ceramic 11 is located is higher than the temperature of the environment where the second piezoelectric ceramic 13 is located, or the temperature of the environment where the second piezoelectric ceramic 13 is located is higher than the temperature of the environment where the first piezoelectric ceramic 11 is located, there is a problem that the electrical signals generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 due to temperature changes are not the same, resulting in the electrical signals not being able to completely cancel each other out. Therefore, in one example, referring to Figures 7 and 8, the piezoelectric sensor 1 further includes a heat-conducting element 14. When the temperature of the environment where the first piezoelectric ceramic 11 is located is higher than the temperature of the environment where the second piezoelectric ceramic 13 is located, the heat-conducting element 14 is located between the first piezoelectric ceramic 11 and the conductive element 12, and is connected to both the first piezoelectric ceramic 11 and the conductive element 12. This heat-conducting element 14 is used to transfer the temperature of the environment where the first piezoelectric ceramic 11 is located to the environment where the second piezoelectric ceramic 13 is located, so that the temperature of the environment where the second piezoelectric ceramic 13 is located can rise to the same temperature as the environment where the first piezoelectric ceramic 11 is located. This ensures that the electrical signals generated by the temperature changes of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are the same, thus avoiding the problem that the electrical signals generated by the temperature changes of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 cannot completely cancel each other out. This ensures the detection accuracy and reliability of the piezoelectric sensor 1, and further ensures the measurement sensitivity and accuracy of the subsequent circuit for measuring the quasi-static force signal.

[0060] In this example, when the temperature of the environment where the second piezoelectric ceramic 13 is located is higher than the temperature of the environment where the first piezoelectric ceramic 11 is located, the heat-conducting element 14 is located between the second piezoelectric ceramic 13 and the conductive element 12, and is connected to the second piezoelectric ceramic 13 and the conductive element 12. It is used to conduct heat from the environment where the second piezoelectric ceramic 13 is located to the environment where the first piezoelectric ceramic 11 is located, so that the temperature of the environment where the first piezoelectric ceramic 11 is located can rise to the same temperature as the environment where the second piezoelectric ceramic 13 is located, so that the heat can be evenly distributed. This makes the electrical signals generated by the temperature changes of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 the same, so as to avoid the problem that the electrical signals generated by the temperature changes of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 cannot completely cancel each other out. This ensures the detection accuracy and reliability of the piezoelectric sensor 1, and thus ensures the measurement sensitivity and measurement accuracy of the quasi-static force signal measured by the subsequent circuit.

[0061] It is worth noting that heat-conducting elements 14 can also be provided between the first piezoelectric ceramic 11 and the conductive element 12, and between the second piezoelectric ceramic 13 and the conductive element 12, to further improve the uniformity of ambient temperature. The specific location of the heat-conducting element 14 can be set according to actual needs, and this application does not impose specific restrictions on it.

[0062] Optionally, the heat-conducting component 14 can be made of conductive copper foil. The conductive copper foil has high thermal conductivity, which enables rapid heat transfer between the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13, so that the heat on the surfaces of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 can be evenly distributed. At the same time, the conductive copper foil can also provide electromagnetic shielding to reduce electromagnetic interference signals and improve the accuracy of the electrical signals generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 under force.

[0063] Optionally, the material of the heat-conducting element 14 can be a thermally conductive gel. The thermally conductive gel can be coated on the surface of the first piezoelectric ceramic 11 or the second piezoelectric ceramic 13 facing the conductive element 12. The gel-like texture allows it to fill the irregular surface gaps of the first piezoelectric ceramic 11, the second piezoelectric ceramic 13, and the conductive element 12. Even tiny gaps can be effectively covered to provide comprehensive thermal contact, optimize the heat conduction path, and further improve the uniformity of heat conduction.

[0064] Optionally, the heat-conducting element 14 can be made of ceramic material or other materials that can conduct heat but are not conductive. This application does not impose specific restrictions on this.

[0065] Optionally, the surface of the heat-conducting component 14 can be grounded to shield high-frequency noise, thereby improving the accuracy of the electrical signals generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 under force.

[0066] To further ensure greater consistency in the number of electrical signals generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 due to the pyroelectric effect, in one example, as shown in Figure 9, the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are disposed adjacent to each other along the second direction BB on one side of the conductive element 12. In this example, the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are fixed on the same surface of the conductive element 12. When directional heat is radiated onto the surface of the piezoelectric sensor 1, or when the piezoelectric sensor 1 is in a confined space (i.e., a scenario with uniform temperature), since the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are on the same surface, their temperatures are the same. This results in a higher consistency in the number of electrical signals generated by the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 due to the pyroelectric effect, thereby further improving the temperature drift resistance of the piezoelectric sensor 1, thus further improving the detection reliability of the piezoelectric sensor 1, and consequently improving the measurement sensitivity and accuracy of the subsequent circuit for measuring quasi-static force.

[0067] In this example, assuming the polarization direction of the first piezoelectric ceramic 11 is downward along the first direction AA, the voltage on the side of the first piezoelectric ceramic 11 facing the conductive element 12 is positive voltage +, and the voltage on the side of the first piezoelectric ceramic 11 away from the conductive element 12 is negative voltage -, then at this time, the polarization direction of the second piezoelectric ceramic 13 is upward along the first direction AA, the voltage on the side of the second piezoelectric ceramic 13 facing the conductive element 12 is negative voltage -, and the voltage on the side of the second piezoelectric ceramic 13 away from the conductive element 12 is positive voltage +.

[0068] For example, as shown in Figure 10, taking the fixed structure 2 using a cantilever beam 21 as an example, assuming that the pressure on the piezoelectric sensor 1 is vertically upward in the first direction AA (i.e., the bending deformation is upward), the piezoelectric sensor 1 will bend due to the external force, and the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are both in a stretched state. At this time, since the positions of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 on one side of the conductive element 12 are not the same, the tensile force f1 on the first piezoelectric ceramic 11 is not the same as the tensile force f1 on the second piezoelectric ceramic 13. When the force point 1A is close to the end where the cantilever beam 21 is not set, that is, close to the second piezoelectric ceramic 13, the tensile force f1 on the first piezoelectric ceramic 11 is greater than the tensile force f1 on the second piezoelectric ceramic 13, and the electrical signals generated by the two tensile forces f1 are opposite. At this time, although the useful signals generated by the piezoelectric sensor 1 cannot be superimposed, they still exist to ensure the detection accuracy of the piezoelectric sensor 1, and thus ensure the ability of the subsequent circuit to resist temperature drift when measuring the quasi-static force signal.

[0069] In summary, when the piezoelectric sensor 1 is not subjected to force, since the polarization directions of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are opposite in the first direction AA, the electrical signals generated by the temperature changes of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 can cancel each other out. This avoids the problem of temperature drift in the piezoelectric ceramics causing the piezoelectric sensor 1 to release charge even when not under force, affecting the detection effect and measurement accuracy of the piezoelectric sensor 1, and consequently causing the test baseline in the subsequent circuit to drift, affecting the measurement sensitivity of quasi-static force. Thus, by canceling out the electrical signals generated by the temperature changes of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13, the detection reliability and accuracy of the piezoelectric sensor 1 can be guaranteed, thereby ensuring the measurement sensitivity and accuracy of the subsequent circuit in measuring quasi-static force. When the piezoelectric sensor 1 is subjected to force in the first direction AA, the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 can generate corresponding charges based on the pressure they bear, enabling the piezoelectric sensor 1 to detect normally, thus ensuring the detection reliability of the piezoelectric sensor 1, and consequently ensuring the measurement sensitivity and accuracy of the subsequent circuit in measuring quasi-static force.

[0070] The first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 are typically brittle materials with low toughness. To prevent the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 from breaking due to external forces, the conductive element 12 can provide better toughness to improve the overall toughness of the piezoelectric sensor 1. It also has a certain degree of conductivity to ensure the reliability of the piezoelectric sensor 1. Furthermore, the conductive element 12 can be used to fix the piezoelectric sensor 1 to a wall, the housing of electronic equipment, or other structures, further improving the stability of the piezoelectric sensor 1 on these surfaces.

[0071] For example, referring to Figures 9 and 10, the length of the conductive element 12 in the second direction BB is greater than the length of the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 in the second direction BB, so as to fix it to the wall, the housing of the electronic device or other structure. The specific lengths of the conductive element 12, the first piezoelectric ceramic 11 and the second piezoelectric ceramic 13 can be set according to actual needs. This application does not impose specific limitations on this.

[0072] Optionally, the conductive component 12 can be made of copper alloy, nickel alloy, iron alloy, titanium alloy, conductive fiberglass board, or other materials that can conduct electricity and have a certain degree of toughness. This application does not impose specific restrictions on this.

[0073] Based on the above embodiments, this application also provides an electronic device, which may include the piezoelectric ceramic device and piezoelectric sensor 1 described in any of the embodiments corresponding to Figures 1 to 10. Because this electronic device is equipped with the piezoelectric ceramic device and piezoelectric sensor 1 of the above embodiments, it possesses all the beneficial effects of the piezoelectric ceramic device and piezoelectric sensor 1 of any of the above embodiments, which will not be repeated here.

[0074] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A piezoelectric sensor (1), characterized in that, It includes a first piezoelectric ceramic (11), a conductive element (12), and a second piezoelectric ceramic (13); The first piezoelectric ceramic (11) and the second piezoelectric ceramic (13) are respectively connected to the conductive element (12), and the polarization directions of the first piezoelectric ceramic (11) and the second piezoelectric ceramic (13) are opposite in the first direction.

2. The piezoelectric sensor (1) according to claim 1, characterized in that, The first piezoelectric ceramic (11) and the second piezoelectric ceramic (13) are respectively attached to the two opposite sides of the conductive element (12) in the first direction.

3. The piezoelectric sensor (1) according to claim 2, characterized in that, The piezoelectric sensor (1) further includes a heat-conducting element (14), which is located between the first piezoelectric ceramic (11) and the conductive element (12) and is connected to the first piezoelectric ceramic (11) and the conductive element (12); or, The heat-conducting element (14) is located between the second piezoelectric ceramic (13) and the conductive element (12), and is connected to the second piezoelectric ceramic (13) and the conductive element (12).

4. The piezoelectric sensor (1) according to claim 3, characterized in that, The material of the heat-conducting component (14) includes any one of conductive copper foil, thermal conductive gel, and ceramic material.

5. The piezoelectric sensor (1) according to claim 1, characterized in that, The first piezoelectric ceramic (11) and the second piezoelectric ceramic (13) are disposed adjacent to each other on one side of the conductive element (12) along the second direction; Wherein, the first direction intersects with the second direction.

6. The piezoelectric sensor (1) according to any one of claims 1-5, characterized in that, The conductive component (12) is made of any one of copper alloy, nickel alloy, iron alloy, titanium alloy and conductive glass fiber board.

7. A piezoelectric ceramic device, characterized in that, include: The piezoelectric sensor (1) as described in any one of claims 1-6; as well as, A fixed structure (2) is fixedly connected to at least one end of the piezoelectric sensor (1).

8. The piezoelectric ceramic device according to claim 7, characterized in that, The fixing structure (2) includes: A cantilever beam (21) is fixedly connected to at least one end of the piezoelectric sensor (1) along a second direction.

9. The piezoelectric ceramic device according to claim 7, characterized in that, The fixing structure (2) includes: Two simply supported beams (22) are fixedly connected to the two ends of the piezoelectric sensor (1) along the second direction.

10. An electronic device, characterized in that, The electronic device includes a piezoelectric ceramic device as described in any one of claims 7 to 9.

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