Piezoelectric coefficient measuring device and detection method

Abstract

The invention relates to the technical field of piezoelectric coefficient measurement, in particular to a piezoelectric coefficient measurement device and a piezoelectric coefficient detection method, and can solve the problems that a fixed frequency mode in the prior art is difficult to be matched with a wide-frequency-domain excitation requirement and a measurement result is easily influenced by contact point position deviation and non-uniform stress distribution to a certain extent. And the high-precision test requirement is difficult to meet. The device comprises a stepping motor control module which is used for realizing precise positioning of a sample table through a double-optical-axis ball screw transmission sliding table and a stepping motor; the vibration exciter-force control module comprises a high-frequency vibration exciter, a piezoresistive film sensor and a silica gel gasket and is used for applying dynamic force and monitoring the dynamic force in real time; the electrometer detection module is used for detecting the quantity of electric charges generated by the sample by adopting an electrometer; the signal processing and collecting module is used for synchronously collecting pressure and charge signals through a data collecting card; and the upper computer processing module is used for realizing signal filtering, piezoelectric coefficient d33 calculation and data storage based on software.

Description

Technical Field

[0001] The present application relates to the technical field of piezoelectric coefficient measurement, and in particular to a piezoelectric coefficient measurement device and detection method. Background Art

[0002] In the process of continuous development of materials science, as the exploration of functional materials performance deepens, people have discovered the unique electromechanical coupling characteristics of piezoelectric materials. The piezoelectric coefficient of a piezoelectric body is its inherent parameter, which is used to describe the amount of charge generated by the piezoelectric material when subjected to mechanical stress. It is also an important parameter for evaluating the electromechanical coupling performance of piezoelectric materials. 33 It is a characteristic parameter that describes the relationship between stress and polarization intensity or electric field and strain in the Z direction or 3 direction (usually polarization direction) of piezoelectric materials. Early research on piezoelectric phenomena only qualitatively understood the conversion relationship between force and electricity in materials. With the development of technology, in order to more accurately study and utilize this material property, it is necessary to 33 Conduct quantitative testing to differentiate the performance of different piezoelectric materials.

[0003] At present, the detection of material piezoelectric coefficient is divided into direct piezoelectric coefficient measurement method and inverse piezoelectric coefficient measurement method. The inverse piezoelectric coefficient measurement method can accurately measure, but the equipment is expensive, the operation is complicated, and the requirements for the test sample are high. The direct piezoelectric coefficient measurement method is simple, convenient and economical. 33 The test method is a method for measuring the equivalent piezoelectric coefficient of piezoelectric materials. Its principle is based on applying a slowly changing (quasi-static) force to the piezoelectric material and then measuring the generated charge or voltage signal. The piezoelectric coefficient is calculated based on the formula: d 33 =Q / F, calculate the true equivalent piezoelectric coefficient d33 of the piezoelectric material film.

[0004] The currently widely used quasi-static 33 Testers generally use a fixed vibration frequency (110 Hz) to detect the piezoelectric coefficient. Although this method is suitable for the characterization of rigid piezoelectric materials such as ceramics, it has significant limitations in the detection of flexible piezoelectric polymer materials. Specifically,

[0005] First, the intrinsic frequency response characteristics of polymer materials are orders of magnitude different from those of hard materials, and fixed-frequency modes are difficult to match their wide-band (e.g., 0.1Hz-10kHz) excitation requirements.

[0006] Secondly, the vibration force is applied by relying on a point-contact electrode with a diameter of about 2 mm, which makes the measurement results easily affected by the position offset of the contact point and uneven stress distribution, making it difficult to meet the needs of high-precision testing. Summary of the Invention

[0007] In order to solve the problems that the fixed frequency mode of the existing technology is difficult to match its wide-band excitation requirements and the measurement results are easily affected by contact point position offset and uneven stress distribution, making it difficult to meet high-precision testing requirements, the present application provides a piezoelectric coefficient measurement device and detection method.

[0008] The embodiment of the present application is implemented as follows:

[0009] In a first aspect, the present application provides a piezoelectric coefficient measuring device, comprising:

[0010] Stepper motor control module, used to achieve precise positioning of the sample stage through a dual-axis ball screw drive slide and a stepper motor;

[0011] The exciter-force control module, which includes a high-frequency exciter, a piezoresistive thin film sensor, and a silicone gasket, is used to apply dynamic force and monitor it in real time;

[0012] The electrometer detection module uses an electrometer to detect the amount of charge generated by the sample;

[0013] Signal processing and acquisition module, which synchronously collects pressure and charge signals through a data acquisition card;

[0014] The host computer processing module realizes signal filtering and piezoelectric coefficient d based on software 33 Calculation and data storage.

[0015] In a possible implementation, the corner support bracket of the stepper motor control module is a double-oblique right-angle structure, has a lateral dimension larger than the slide, is made of stainless steel, and is fixed to the slide by screws.

[0016] In a possible implementation, the piezoresistive thin film sensor needs to meet the requirements of a wide response range and an ultra-low response time.

[0017] In a possible implementation, a silicone gasket is bonded between the pressure sensor and the excitation head to ensure that the excitation force is evenly transmitted to the sensor film.

[0018] In one possible implementation, the data acquisition card supports 8-channel input, a resolution of 16 bits, a minimum sampling resolution of 152 μV@5V, and a sampling rate of 200 kSPS Max, realizing synchronous acquisition of pressure and charge signals.

[0019] In a second aspect, the present application provides a piezoelectric coefficient detection method, comprising:

[0020] Before the test, prepare a flat sample, start the signal generator, amplifier and host computer in sequence, and calibrate the pressure sensor with weights and the electrometer with standard samples;

[0021] In actual testing, after loading the sample, a dynamic force of 0.1Hz to 10kHz is applied through a high-frequency exciter, and the pressure and charge signals are collected synchronously;

[0022] Data storage, filter data in the signal stability range, generate pressure value, charge value and piezoelectric coefficient d 33 Data sheet.

[0023] In a possible implementation, the pressure sensor calibration establishes a pressure-voltage relationship through function fitting, and the electrometer calibration calculates a linear function through five measurements.

[0024] In one possible implementation, when saving data, it is necessary to ensure that the pressure signal fluctuation is less than 1% and the charge signal baseline offset is less than 0.5%.

[0025] In a possible implementation, the high-frequency exciter supports full-band excitation to meet the broadband response requirements of flexible materials.

[0026] In a possible implementation, the sample electrode is prepared by a sputtering process, with a surface roughness of <0.1 μm, to ensure charge detection accuracy.

[0027] The technical solution provided by this application can achieve at least the following beneficial effects:

[0028] This application provides a piezoelectric coefficient measurement device and detection method that, by breaking through the traditional fixed-frequency model, achieves full coverage across ultra-low frequency, low frequency, high frequency, and ultra-high frequency bands, accurately matching the frequency response characteristics of different piezoelectric polymer materials. This device also supports precise control of the contact area and selectively detects the piezoelectric properties of the material itself in different regions, enhancing practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] Figure 1 1 is a schematic structural diagram of a piezoelectric coefficient measuring device according to an exemplary embodiment of the present application;

[0031] Figure 2 This is a schematic diagram of a dual-axis ball screw linear module guide rail aluminum transmission slide with a 57 stepper motor shown in an exemplary embodiment of the present application;

[0032] Figure 3(a) is a schematic CAD parametric drawing of an angle bracket support bracket shown in an exemplary embodiment of the present application;

[0033] Figure 3 (b) is a schematic diagram of a corner support bracket according to an exemplary embodiment of the present application;

[0034] Figure 4 is a schematic diagram of a piezoresistive sensor shown in an exemplary embodiment of the present application;

[0035] Figure 5 (a) is a schematic diagram of the front panel of a TH2690 electrometer shown in an exemplary embodiment of the present application;

[0036] Figure 5 (b) is a schematic diagram of the rear panel of a TH2690 electrometer shown in an exemplary embodiment of the present application;

[0037] Figure 6 This is a schematic diagram of the pressure sensor and electrometer host computer interface shown in an exemplary embodiment of the present application;

[0038] Figure 7 (a) is a schematic diagram of an interface for adjusting the frequency and amplitude of an exciter, shown in an exemplary embodiment of the present application;

[0039] Figure 7 (b) is a schematic diagram of a real-time monitoring image of a pressure sensor host computer shown in an exemplary embodiment of the present application;

[0040] Figure 7 (c) is a schematic diagram of a real-time monitoring image of an electrometer host computer shown in an exemplary embodiment of the present application;

[0041] Figure 7 (d) is a schematic diagram of an image of a piezoelectric coefficient monitored in real time by a host computer software according to an exemplary embodiment of the present application;

[0042] Figure 8 It is a flow chart of a piezoelectric coefficient detection method shown in an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to make the purpose, implementation methods and advantages of the present application clearer, the exemplary implementation methods of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, not all of the embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0044] It should be noted that the brief descriptions of terms in this application are only for the purpose of facilitating the understanding of the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their ordinary and usual meanings.

[0045] In the specification and claims of this application and the accompanying drawings, the terms "first," "second," "third," etc. are used to distinguish similar or similar objects or entities, and are not necessarily intended to limit a particular order or sequence, unless otherwise noted. It should be understood that the terms used in this manner are interchangeable under appropriate circumstances.

[0046] The terms "comprise," "include," and "have," and any variations thereof, are intended to cover but not exclude inclusion; for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0047] Before explaining the piezoelectric coefficient measurement device provided in the embodiment of the present application, the application scenario and implementation environment of the embodiment of the present application are first introduced.

[0048] In the process of continuous development of materials science, as the exploration of functional materials performance deepens, people have discovered the unique electromechanical coupling characteristics of piezoelectric materials. The piezoelectric coefficient of a piezoelectric body is its inherent parameter, which is used to describe the amount of charge generated by the piezoelectric material when subjected to mechanical stress. It is also an important parameter for evaluating the electromechanical coupling performance of piezoelectric materials. 33 It is a characteristic parameter that describes the relationship between stress and polarization intensity or electric field and strain in the Z direction or 3 direction (usually polarization direction) of piezoelectric materials. Early research on piezoelectric phenomena only qualitatively understood the conversion relationship between force and electricity in materials. With the development of technology, in order to more accurately study and utilize this material property, it is necessary to 33 Conduct quantitative testing to differentiate the performance of different piezoelectric materials.

[0049] At present, the detection of material piezoelectric coefficient is divided into direct piezoelectric coefficient measurement method and inverse piezoelectric coefficient measurement method. The inverse piezoelectric coefficient measurement method can accurately measure, but the equipment is expensive, the operation is complicated, and the requirements for the test sample are high. The direct piezoelectric coefficient measurement method is simple, convenient and economical. 33 The test method is a method for measuring the equivalent piezoelectric coefficient of piezoelectric materials. Its principle is based on applying a slowly changing (quasi-static) force to the piezoelectric material and then measuring the generated charge or voltage signal. The piezoelectric coefficient is calculated based on the formula: d 33 =Q / F, calculate the true equivalent piezoelectric coefficient d33 of the piezoelectric material film.

[0050] The currently widely used quasi-static 33 Testers generally use a fixed vibration frequency (110 Hz) to detect the piezoelectric coefficient. Although this method is suitable for the characterization of rigid piezoelectric materials such as ceramics, it has significant limitations in the detection of flexible piezoelectric polymer materials. Specifically,

[0051] First, the intrinsic frequency response characteristics of polymer materials are orders of magnitude different from those of hard materials, and fixed-frequency modes are difficult to match their wide-band (e.g., 0.1Hz-10kHz) excitation requirements.

[0052] Secondly, the vibration force is applied by relying on a point-contact electrode with a diameter of about 2 mm, which makes the measurement results easily affected by the position offset of the contact point and uneven stress distribution, making it difficult to meet the needs of high-precision testing.

[0053] Based on this, this application provides a piezoelectric coefficient measurement device and detection method. By breaking through the traditional fixed frequency mode, it achieves full frequency coverage of ultra-low frequency, low frequency, high frequency, and ultra-high frequency, and accurately matches the frequency response characteristics of different piezoelectric polymer materials. It also supports precise control of the contact area and selectively detects the piezoelectric performance of the material itself in different areas, improving practicality.

[0054] Next, the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems will be described in detail through embodiments and in conjunction with the accompanying drawings. The various embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, not all of them.

[0055] Figure 1 Schematic diagram of a piezoelectric coefficient measuring device according to an exemplary embodiment of the present application.

[0056] In an exemplary embodiment, Figure 1 As shown, a piezoelectric coefficient measuring device is provided. In this embodiment, the device may include:

[0057] Stepper motor control module, used to achieve precise positioning of the sample stage through a dual-axis ball screw drive slide and a stepper motor;

[0058] The exciter-force control module, which includes a high-frequency exciter, a piezoresistive thin film sensor, and a silicone gasket, is used to apply dynamic force and monitor it in real time;

[0059] The electrometer detection module uses an electrometer to detect the amount of charge generated by the sample;

[0060] Signal processing and acquisition module, which synchronously collects pressure and charge signals through a data acquisition card;

[0061] The host computer processing module realizes signal filtering and piezoelectric coefficient d based on software 33 Calculation and data storage.

[0062] Figure 2 This is a schematic diagram of a dual-axis ball screw linear module guide rail aluminum transmission slide with a 57 stepper motor shown in an exemplary embodiment of the present application.

[0063] In one possible implementation, Figure 1 As shown, the specific settings of the device are as follows:

[0064] The stepper motor control module carries the sample stage, helps load and unload the sample, and controls the distance between the sample and the excitation head sensor; the exciter-force control module controls the pressure, and the pressure sensor is attached to the excitation head to feedback the excitation pressure value; the electrometer detection module detects the charge value output by the sample under the required pressure; the signal processing and acquisition module amplifies and collects the pressure signal and charge signal, and feeds it back to the host computer; the host computer processing module displays the pressure and charge signals in real time, calculates the piezoelectric coefficient according to the formula, and saves the test data.

[0065] Preferably, the stepper motor control module includes a dual-axis ball screw transmission slide, a stepper motor driver and an angle seat support bracket.

[0066] In this embodiment, the stepper motor is a 57 stepper motor. Figure 2 The slide screw has a diameter of 16mm, a screw accuracy of 0.03mm, a pitch of 5mm, an effective travel of 100mm, and a screw load capacity of 30kg and 20kg, respectively. The stepper motor control module driver in this embodiment is RS232 and includes a USB component for precise control from a host computer. Connect the driver to the stepper motor control module and connect it to an external 24V power supply.

[0067] Figure 3 (a) is a schematic diagram of a CAD parameter drawing of an angle support bracket shown in an exemplary embodiment of the present application, Figure 3 (b) is a physical schematic diagram of an angle seat support bracket shown in an exemplary embodiment of the present application.

[0068] In this embodiment, a customized sample stage is used. Figure 3 The corner support bracket needs to have double oblique right-angle supports to improve the stability of the sample stage during actual high-frequency testing; the material is stainless steel to ensure that the sample stage will not deform or resonate during the excitation process; the lateral size is 2cm larger than the slide, meeting the test conditions of all experimental distances; the bottom is connected to the slide block group through M5 screws to ensure test stability.

[0069] Preferably, the exciter-force control module includes a signal generator, a signal amplifier, a high-frequency exciter and a pressure sensor.

[0070] Figure 4 Schematic diagram of a piezoresistive sensor according to an exemplary embodiment of the present application.

[0071] In this embodiment, the exciter-force control module adopts the German SPEKTRA high-frequency exciter with a maximum excitation frequency of 5kHz and a maximum excitation force of 100N; the signal generator model is DG1022 and the signal amplifier model is HEA-200C; the above equipment can meet the testing requirements of various actual situations in piezoelectric materials. In order to ensure stable pressure output and controllable output area, a customized fine flat excitation head is used. The flat surface is circular and the diameter size is 12, 20, 30 or 38 mm.

[0072] In order to detect the actual pressure generated by the exciter on the sample surface, the pressure sensor is attached to the surface of the exciter head. At the same time, to ensure that all the generated force can act on the pressure sensor, a silicone gasket is glued between the pressure sensor film and the flat exciter head. In the embodiment, the pressure sensor adopts a piezoresistive film sensor, refer to the attached Figure 4 The response range is 2g~1.5kg, and the response time is less than 10μs.

[0073] Figure 5 (a) is a schematic diagram of the front panel of a TH2690 electrometer shown in an exemplary embodiment of the present application, Figure 5 (b) is a schematic diagram of the rear panel of the TH2690 electrometer shown in an exemplary embodiment of the present application.

[0074] Preferably, the electrometer detection module adopts the TH2690 Tonghui electrometer with a current resolution of 0.01fA (10A-17A), which can realize weak current recording. The electrometer can convert the measured charge signal into an AD signal, and output the capacitance signal measured by the electrometer as an AD signal analog output through the analog signal connector.

[0075] Reference Attachment Figure 5 , connect the three-pin connector to the DAQ122 data acquisition card. From left to right, pin 1 is the analog signal ground, and pin 3 is the analog signal output. It always outputs a voltage proportional to the current measurement result, and the maximum output voltage is ±2V.

[0076] Preferably, the signal processing and acquisition module includes a signal amplifier and a data acquisition card, and amplifies the pressure signal of the pressure sensor and the charge signal of the electrometer through the signal amplifier and transmits them to the data acquisition card.

[0077] In this embodiment, the data acquisition card model is Lingzhi Electronics DAQ122 8-channel data acquisition card with a resolution of 16 bits, a minimum sampling resolution of 152 μV@5V, and a sampling rate of 200 kSPS Max.

[0078] Preferably, the host computer processing module includes a stepper motor control host computer and a pressure and charge signal processing host computer.

[0079] Figure 6 It is a schematic diagram of the pressure sensor and electrometer host computer interface shown in an exemplary embodiment of the present application.

[0080] In this embodiment, the stepper motor control host computer controls the stepper motor speed and pulse to control the stepping distance, and at the same time, the pressure and charge signal processing host computer adopts Lebview for secondary programming development.

[0081] Reference Attachment Figure 6 After filtering and calculation functions of the programming software, the pressure signal, charge signal and calculated piezoelectric coefficient signal are obtained. The computer software can realize continuous collection of exciting force, and observe the real-time data curve of force and time and the real-time data curve of charge. At the same time, the data of each point can be saved in real time, so as to further process the exciting force data, charge data and piezoelectric coefficient signal data.

[0082] It should be understood that, although the various steps in the flowcharts involved in the above-described embodiments are displayed in sequence according to the instructions, these steps are not necessarily executed in the order indicated. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0083] Corresponding to the aforementioned embodiment of the piezoelectric coefficient measuring device, the present application also provides an embodiment of a piezoelectric coefficient detection method.

[0084] Figure 8 It is a flow chart of a piezoelectric coefficient detection method shown in an exemplary embodiment of the present application.

[0085] In an exemplary embodiment, Figure 8 As shown, the piezoelectric coefficient detection method may include the following steps:

[0086] Step 100: Prepare before the test, prepare a flat sample, start the signal generator, amplifier and host computer in sequence, and calibrate the pressure sensor with weights and the electrometer with standard samples.

[0087] Step 200: Actual test: After loading the sample, a dynamic force of 0.1 Hz to 10 kHz is applied through a high-frequency exciter, and pressure and charge signals are collected synchronously.

[0088] Step 300: Save data, filter data in the signal stability range, generate pressure value, charge value and piezoelectric coefficient d 33 Data sheet.

[0089] Figure 7 (a) is a schematic diagram of an interface for adjusting the frequency and amplitude of an exciter, shown in an exemplary embodiment of the present application. Figure 7 (b) is a schematic diagram of a real-time monitoring image of a pressure sensor host computer shown in an exemplary embodiment of the present application, Figure 7 (c) is a schematic diagram of a real-time monitoring image of an electrometer host computer shown in an exemplary embodiment of the present application, Figure 7 (d) is a schematic diagram of an image of a piezoelectric coefficient monitored in real time by a host computer software, as shown in an exemplary embodiment of the present application.

[0090] In a possible implementation, the method is specifically implemented as follows:

[0091] In this embodiment, the preparation before the test includes test sample preparation, equipment startup and device calibration.

[0092] The test sample needs to be as flat as possible; the side length of the square sample ranges from 1cm to 6cm, and the diameter of the disc ranges from 1cm to 6cm; the electrode material can be one or more of Au, Ag, Pt, Cu, and C.

[0093] The equipment startup sequence is: 1. Signal generator; 2. Signal amplifier; 3. Stepper motor control host computer and pressure and charge signal processing host computer. The device calibration includes the calibration of the pressure sensor and the calibration of the electrometer.

[0094] In this embodiment, the pressure sensor is calibrated using a weight ranging from 20 g to 1500 g. After function fitting, a functional relationship between pressure and voltage signals is obtained and input into the host computer background program.

[0095] The specific process of electrometer calibration is as follows: load the standard sample, measure five values, calculate the linear function, and input it into the host computer background program.

[0096] Preferably, the actual test sequence is: loading the sample, operating the exciter, and feedback of the pressure and charge signals. When the data is saved, the pressure and charge signals must remain relatively stable, and the piezoelectric coefficient baseline must be relatively flat. When the pressure and charge values are kept relatively stable, the baseline of the page curve (the red line part), that is, the measured piezoelectric coefficient, is shown in the attached figure. Figure 7 The data is saved as a table of data points for the pressure, charge, and piezoelectric constant values measured in the next stage. Based on the test results, the piezoelectric performance of the sample is analyzed and the test results are plotted and evaluated in Origin.

[0097] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The embodiments described above merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A piezoelectric coefficient measuring device, characterized in that: include: Stepper motor control module, used to achieve precise positioning of the sample stage through a dual-axis ball screw drive slide and a stepper motor; The exciter-force control module, which includes a high-frequency exciter, a piezoresistive thin film sensor, and a silicone gasket, is used to apply dynamic force and monitor it in real time; The electrometer detection module uses an electrometer to detect the amount of charge generated by the sample; Signal processing and acquisition module, which synchronously collects pressure and charge signals through a data acquisition card; The host computer processing module realizes signal filtering and piezoelectric coefficient d based on software 33 Calculation and data storage.

2. The piezoelectric coefficient measuring device according to claim 1, wherein: The corner support bracket of the stepper motor control module is a double oblique right-angle structure, has a lateral dimension larger than the slide, is made of stainless steel, and is fixed to the slide by screws.

3. The piezoelectric coefficient measuring device according to claim 1, wherein: The piezoresistive thin film sensor needs to meet the requirements of a wide response range and an ultra-low response time.

4. The piezoelectric coefficient measuring device according to claim 1, wherein: A silicone gasket is bonded between the pressure sensor and the excitation head to ensure that the excitation force is evenly transmitted to the sensor film.

5. The piezoelectric coefficient measuring device according to claim 1, wherein: The data acquisition card supports 8-channel input, a resolution of 16 bits, a minimum sampling resolution of 152μV@5V, and a sampling rate of 200kSPS Max, enabling synchronous acquisition of pressure and charge signals.

6. A piezoelectric coefficient detection method, characterized in that: include: Before the test, prepare a flat sample, start the signal generator, amplifier and host computer in sequence, and calibrate the pressure sensor with weights and the electrometer with standard samples; In actual testing, after loading the sample, a dynamic force of 0.1Hz to 10kHz is applied through a high-frequency exciter, and the pressure and charge signals are collected synchronously; Data storage, filter data in the signal stability range, generate pressure value, charge value and piezoelectric coefficient d 33 Data sheet.

7. The piezoelectric coefficient measuring device according to claim 6, wherein: The pressure sensor calibration establishes a pressure-voltage relationship by function fitting, and the electrometer calibration calculates a linear function by five measurements.

8. The piezoelectric coefficient measuring device according to claim 6, wherein: When saving data, ensure that the pressure signal fluctuation is <1% and the charge signal baseline offset is <0.5%.

9. The piezoelectric coefficient measuring device according to claim 6, wherein: The high-frequency exciter supports full-band excitation and is adapted to the broadband response requirements of flexible materials.

10. The piezoelectric coefficient measuring device according to claim 6, wherein: The sample electrode is prepared by sputtering process, and the surface roughness is less than 0.1 μm, which ensures the accuracy of charge detection.

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