Flexible pressure sensor

Abstract

The invention discloses a flexible pressure sensor. The flexible pressure sensor comprises a sensing part and a driving circuit. The sensing part comprises a base material, a sealing material, positive and negative sensing electrodes and an internal resistance element; the driving circuit is sequentially connected with an external power supply, an external resistor, an operational amplifier, an analog-digital converter and a micro-control unit. The flexible pressure sensor provided by the invention can be connected to a circuit in sequence according to the stress condition, and the pressure value and the change trend are calculated through the micro-control unit, so that high-precision and multi-section pressure detection is realized, the limitation of a traditional pressure sensor in the aspects of flexibility, precision and multi-section pressure detection is solved, and the flexibility, the accuracy and the multi-section pressure detection are improved. The device has the advantages that the pressure detection precision and resolution are improved, multi-section pressure measurement is realized, and the bent surface pressure measurement requirement is met.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and particularly to a flexible pressure sensor. Background Art

[0002] In the current field of sensor technology, pressure sensors are widely used in various scenarios. However, traditional pressure sensors have significant limitations in terms of flexibility, accuracy of pressure detection, and multi-segment pressure detection. Many traditional pressure sensors use a single sensing element, which can only provide a single pressure threshold information and is difficult to accurately distinguish and finely measure pressures in different magnitude ranges. This design is particularly unsuitable for application scenarios with flexible requirements. For example, in wearable devices, traditional rigid sensors may affect the wearing comfort and usage effect.

[0003] With the rapid development of flexible electronics technology, the market demand for sensors that can conform to different shaped surfaces, withstand a certain degree of deformation while accurately measuring pressure is increasing. However, the existing technologies still face many challenges in achieving high-resolution and multi-segment pressure measurement. This is difficult to meet the usage requirements in scenarios that require accurate pressure information, such as pressure monitoring in medical devices and tactile feedback in precision robots.

[0004] In addition, when existing sensors are actually applied, they often need to be designed with corresponding structures and matching circuits for specific application scenarios to be used. Some sensors have complex structures and large volumes, while others have problems with low stability and accuracy. More intractably, the performance of these sensors will also fluctuate significantly with factors such as environmental temperature and humidity, affecting the reliability and consistency of measurement.

[0005] In a complex pressure change environment, traditional sensors cannot accurately feedback the magnitude and change trend of pressure, which severely limits their applications in the fields of dynamic pressure monitoring and precision control. In addition, the insufficient flexibility of traditional pressure sensors makes it difficult to adapt to the pressure measurement requirements of curved or irregular surfaces, causing application bottlenecks in emerging fields such as human-computer interaction and soft robots.

[0006] In view of the above problems, the existing technologies urgently need to be improved. Summary of the Invention

[0007] To solve at least one of the problems existing in the above-mentioned prior art, the present application provides a flexible pressure sensor, which includes a sensing part and a driving circuit;

[0008] The sensing part includes:

[0009] A substrate and a sealing material, serving as an attachment layer for a semi-conductive material, for isolating the outside;

[0010] Positive and negative sensing electrodes, made of conductive materials, can be adjusted in flexibility, size, spacing and shape according to application requirements;

[0011] An internal resistance element, composed of a semi-conductive material, is located between the positive and negative sensing electrodes, and the upper and lower electrodes are in contact through the semi-conductive material to form a conduction path; wherein the internal resistance element includes: a long contact resistance, a middle contact resistance and a short contact resistance, and the contact lengths of the long contact resistance, the middle contact resistance and the short contact resistance are different; and the plurality of internal resistance elements can conduct a circuit by utilizing the force deformation of the flexible pressure sensor: the flexible pressure sensor is deformed according to the pressure it is subjected to and is sequentially connected to the circuit, and the two ends of the sensing part are respectively connected to the driving circuit to provide a voltage source;

[0012] The driving circuit is connected in sequence with:

[0013] External power supply;

[0014] An external resistor, wherein the external resistor and the sensing unit together form a voltage divider circuit;

[0015] An operational amplifier, used to amplify the analog voltage signal output by the sensor unit;

[0016] an analog-to-digital converter, converting the amplified analog voltage signal into a digital voltage signal;

[0017] A microcontrol unit, a receiving end of which receives the digital voltage signal from the analog-to-digital converter, calculates the total resistance value of the internal resistance element of the sensing part through the digital voltage signal, and infers the pressure value and change trend of the flexible pressure sensor according to the flexibility coefficient of the positive and negative sensing electrodes; the output end of the microcontrol unit is connected to the external device for communication.

[0018] In the flexible pressure sensor as described above, optionally, the long contact resistor is first connected to the circuit when subjected to pressure, and provides initial pressure information through changes in its own resistance and changes in the voltage division relationship.

[0019] In the flexible pressure sensor as described above, optionally, the middle contact resistor is connected to the circuit when the pressure reaches a preset threshold, and works together with the long contact resistor and the short contact resistor to improve the accuracy and resolution of pressure detection.

[0020] In the flexible pressure sensor as described above, optionally, the short contact resistor is connected to the circuit when the pressure exceeds the preset threshold, and together with the long contact resistor and the middle contact resistor, covers different pressure ranges to ensure the integrity and accuracy of pressure detection.

[0021] In the flexible pressure sensor as described above, optionally, the long contact resistance, the medium contact resistance, and the short contact resistance are evenly distributed in the sensing part and are in a parallel state when multiple resistances are connected.

[0022] In the flexible pressure sensor as described above, optionally, when the sensing part is under pressure and the long contact resistance first accesses the circuit due to its longer contact, the total voltage of the flexible pressure sensor at this time is:

[0023]

[0024] where r 1 is the total resistance of the long contact resistance in the sensing part, V cc is the voltage applied to the driving circuit, R is the external resistance, and V is the total voltage;

[0025] When the flexible pressure sensor is continuously under force and the medium contact resistance accesses the circuit, the total voltage of the flexible pressure sensor is:

[0026]

[0027] where r 2 is the total resistance of the medium contact resistance in the sensing part;

[0028] When the short contact resistance accesses the circuit, the total voltage of the flexible pressure sensor is:

[0029]

[0030] where r 3 is the total resistance of the short contact resistance in the sensing part.

[0031] In the flexible pressure sensor as described above, optionally, the positive and negative induction electrode materials of the flexible pressure sensor use conductive silver paste and are made on the flexible substrate of the base material through screen printing technology.

[0032] In the flexible pressure sensor as described above, optionally, the semiconductive material of the internal resistance element uses a composite material of carbon nanotubes and polymers, and the resistance value of the semiconductive material is precisely controlled by adjusting the content of carbon nanotubes.

[0033] In the flexible pressure sensor as described above, optionally, for applications that need to measure the pressure on a curved surface, the sensing part is in a spiral or wavy shape to improve flexibility and conformability.

[0034] In the flexible pressure sensor as described above, optionally, the base material uses medical-grade silicone.

[0035] Compared with the prior art, the beneficial effects of a flexible pressure sensor provided by the present application are as follows:

[0036] 1. By internally setting long contact resistors, medium contact resistors, and short contact resistors with different contact lengths, they can be connected to the circuit in sequence according to the magnitude of the applied pressure, enabling segmented detection of different pressure ranges. This multi-segment design can cover a wide pressure range and provide richer information for different pressure stages, effectively improving the accuracy and resolution of pressure detection. Thus, it can more precisely sense different degrees of pressure and provide a more detailed pressure measurement solution for various application scenarios that require accurate pressure information.

[0037] 2. The sensor structure design of the present application endows it with good flexibility, making it suitable for applications in environments that require bending, stretching, or conforming to curved surfaces, such as wearable devices and flexible electronic skins. It will not affect its normal pressure measurement function due to the bending deformation of the device, greatly expanding its scope of use and providing an ideal pressure sensing solution for the development of flexible electronic devices and intelligent wearable devices, improving the user experience.

[0038] 3. In combination with an operational amplifier, an analog-to-digital converter, and a microcontroller unit, the signals output by the sensor can be amplified, converted, and precisely processed. The microcontroller unit can accurately judge the magnitude and change trend of the pressure. It can not only achieve high-precision pressure measurement but also conduct in-depth analysis of the measurement results to meet the requirements of different application scenarios. At the same time, its communication function with external devices enables the convenient transmission and utilization of measurement data, facilitating system integration and remote monitoring.

[0039] In summary, a flexible pressure sensor provided by the present application can be connected to the circuit in sequence according to the force condition, and the microcontroller unit calculates the pressure value and change trend, thereby realizing high-precision, multi-segment pressure detection, solving the limitations of traditional pressure sensors in terms of flexibility, accuracy, and multi-segment pressure detection, and having the advantages of improving the accuracy and resolution of pressure detection, realizing multi-segment pressure measurement, and adapting to the pressure measurement requirements of curved surfaces.

[0040] The following will further illustrate the concept, specific structure, and technical effects generated by the present application in conjunction with the accompanying drawings to fully understand the purpose, features, and effects of the present application. Description of the Drawings

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 It is a schematic structural diagram of an embodiment of a flexible pressure sensor of the present application;

[0043] Figure 2 is Figure 1 a schematic structural diagram of an embodiment of the sensing part of the flexible pressure sensor in

[0044] Figure 3 It is an example diagram of the measured points of the resistance value and pressure of the test data of the flexible pressure sensor of the present application.

[0045] Explanation of reference numerals:

[0046] 1 - sensing part, 101 - long contact resistance, 102 - medium contact resistance, 103 - short contact resistance;

[0047] 2 - external resistor;

[0048] 3 - operational amplifier;

[0049] 4 - analog - to - digital converter;

[0050] 5 - micro - control unit. Detailed implementation manners

[0051] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, rather than all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0052] In the description of the present application, if the term "a plurality of" appears, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0053] As Figure 1 shown, a flexible pressure sensor disclosed in the present application may include a sensing part 1 and a driving circuit.

[0054] The sensing part 1 may include a base material and a sealing material, positive and negative sensing electrodes, and an internal resistance element.

[0055] Specifically, the base material and the sealing material are used to isolate the outside world and connect the pressure sensing area (i.e., the sensing part 1), and the inner side thereof needs to be kept highly flat and smooth. The positive and negative sensing electrodes are made of conductive materials and can adjust their flexibility, size, spacing and shape according to application requirements. The internal resistance element is made of a semiconductive material. The internal resistance element is located between the positive and negative sensing electrodes and has a definite and stable conductivity. The upper and lower electrodes are in contact through the semiconductive material to form a conduction path.

[0056] In this embodiment, as Figure 2 shown, the internal resistance element may specifically include: a long contact resistance 101, a medium contact resistance 102 and a short contact resistance 103, and the contact lengths of the long contact resistance 101, the medium contact resistance 102 and the short contact resistance 103 are different. Moreover, multiple internal resistance elements can conduct the circuit by the force deformation of the flexible pressure sensor: generate deformation according to the pressure received by the flexible pressure sensor and are connected to the circuit in sequence. Both ends of the sensing part 1 can be connected to the driving circuit through the sensor interface to provide a voltage source.

[0057] Furthermore, in an alternative embodiment, the long contact resistance 101 plays a key role in solving the problem of providing initial pressure information. When the flexible pressure sensor is under pressure, due to its longer contact, the long contact resistance 101 is first connected to the circuit. At this time, through the change of the resistance of the long contact resistance 101 and the change of the voltage division relationship, the initial pressure information can be provided. This design enables the pressure sensor to immediately feedback the pressure information when initially under pressure, which helps to improve the response speed and initial accuracy of pressure detection. In this embodiment, the contact length of the long contact resistance 101 can be adjusted according to actual needs to optimize its response ability to the initial pressure.

[0058] The role of the medium contact resistance 102 is to be connected to the circuit when the pressure reaches a specific threshold value. This feature enables the sensor to provide more accurate detection in different pressure ranges. Similarly, the short contact resistance 103 is connected to the circuit when the pressure received exceeds the preset threshold value, and together with the long contact resistance 101 and the medium contact resistance 102, it covers different pressure ranges to ensure the integrity and accuracy of pressure detection.

[0059] It can be seen therefrom that the cooperative work of the contact resistances with different lengths, through a multi-stage pressure detection method, can finely distinguish and measure pressures of different magnitudes, thereby improving the accuracy and resolution of pressure detection, enabling the sensor to achieve higher-precision detection in different pressure ranges, cover a wider pressure range, and provide accurate measurement results in each pressure range.

[0060] The long contact resistance 101, the medium contact resistance 102 and the short contact resistance 103 can be evenly distributed in the sensing part 1 and are in a parallel state when multiple resistances are connected.

[0061] Specifically, the contact of the long contact resistance 101 is longer than that of the medium contact resistance 102, and the contact of the medium contact resistance 102 is longer than that of the short contact resistance 103. When the sensing part 1 is under pressure, when the long contact resistance 101 first accesses the circuit due to its longer contact, the total voltage of the flexible pressure sensor at this time is:

[0062]

[0063] where r 1 is the total resistance of the long contact resistance in the sensing part, V cc is the voltage connected to the drive circuit, R is the external resistance, and V is the total voltage.

[0064] When the flexible pressure sensor continues to be stressed and the deformation of the sensing part 1 reaches the contact of the medium contact resistance 102, the medium contact resistance 102 accesses the circuit. At this time, the total voltage of the flexible pressure sensor is:

[0065]

[0066] where r 2 is the total resistance of the medium contact resistance in the sensing part.

[0067] When the force continues to increase and the deformation of the sensing part 1 reaches the contact of the short contact resistance 103, the short contact resistance 103 accesses the circuit. At this time, the total voltage of the flexible pressure sensor is:

[0068]

[0069] where r 3 is the total resistance of the short contact resistance in the sensing part.

[0070] The drive circuit can be sequentially connected with an external power supply, an external resistor 2, an operational amplifier 3, an analog-to-digital converter 4, and a microcontroller unit 5.

[0071] Specifically, the external power supply can be set according to the specific usage scenario. The external resistor 2 and the sensing part 1 together form a voltage divider circuit. Since the original signal output by the sensing part 1 may be relatively weak, the operational amplifier 3 can enhance the strength of the signal, making it easier to process and analyze it in the subsequent process, ensuring the stability and reliability of the signal during transmission, and reducing signal distortion and noise interference. The analog-to-digital converter 4 converts the amplified analog voltage signal into a digital voltage signal, which is convenient for the microcontroller unit 5 to process and analyze, realizes the connection between the analog signal and the digital system, and makes the output of the sensing part 1 compatible with modern electronic control systems, improving the accuracy and efficiency of data processing. The receiving end of the microcontroller unit 5 receives the digital voltage signal from the analog-to-digital converter 4, calculates the total resistance value of the internal resistance element of the sensing part 1 through the digital voltage signal, and calculates the pressure value and change trend of the flexible pressure sensor according to the flexibility coefficient of the positive and negative sensing electrodes. In this embodiment, the output end of the microcontroller unit 5 can be connected to an external device for communication. Among them, optionally, the external device can be a personal terminal, a server or a network device.

[0072] In this embodiment, when different contact resistors in the sensing part 1 are connected, they together with the external resistor 2 determine the voltage distribution in the circuit, thereby affecting the output voltage. This design is also an important component of calculating the voltage value corresponding to the pressure applied to the sensor.

[0073] For example, a 20mm rubber test head is used to perform pressure testing on a flexible pressure sensor. The experimental test data is shown in Table 1 below:

[0074] Pressure / kg 2 4 6 8 10 12 14 16 18 20 Resistance value / kΩ 20.55 13.55 11.38 10.38 9.81 9.46 9.22 9.05 8.94 8.85

[0075] Table 1

[0076] Based on the above data, we can generate Figure 3 The example diagram of the resistance and pressure measurement points shown in the figure shows the curve relationship between pressure and resistance.

[0077] For another example, the sensing part 1 is subjected to pressure F and produces deformation ε, and the deformation formula is: F = kε. Where k is the deformation coefficient of the substrate of the sensing part 1. For example, when the deformation of the sensing part 1 causes eight long contact resistors 101, five medium contact resistors 102, and three short contact resistors 103 to contact, the total resistance r at this time is: The size and direction of the external force on the sensor can be inferred by the number and length of contact resistance contacts.

[0078] Therefore, the change in the total resistance can be converted into the magnitude of the external force. Forces in different directions will result in different combinations of contact resistances of the contacts. By analyzing the distribution of the contact resistances of the contacts in contact, the orientation of the force can be inferred. For example, if mainly the long contact resistances are in contact, it may indicate that the force direction is in a certain specific direction; if the medium contact resistances and the short contact resistances are in contact simultaneously, it may indicate that the force direction is in another direction.

[0079] In an alternative embodiment, the flexible pressure sensor may further include connection lines for connecting the plurality of sensing portions 1.

[0080] In an alternative embodiment, the positive and negative sensing electrode materials of the flexible pressure sensor may use conductive silver paste, which is fabricated on the flexible substrate of the base material through screen printing technology. The selection of this material and fabrication process aims to improve the flexibility and adaptability of the sensor, ensuring that it can better conform to surfaces of various shapes and still maintain good performance in application scenarios with high flexibility requirements. As the sensing electrode material, conductive silver paste has good conductivity and flexibility, while screen printing technology provides an efficient and precise fabrication method, enabling the electrodes to firmly adhere to the flexible substrate, thereby forming a stable and reliable circuit connection. Through this technical means, the flexible pressure sensor can still achieve precise pressure detection while maintaining high flexibility, solving the limitations of traditional rigid sensors in flexible application scenarios.

[0081] Specifically, the use of conductive silver paste can ensure that the electrodes still maintain good conductive performance under bending and deformation conditions. Screen printing technology can precisely control the shape and thickness of the electrodes, enabling the electrodes to be evenly distributed on the flexible substrate. Further, the composition of the conductive silver paste and the parameters of screen printing can be adjusted according to specific application requirements to optimize the performance of the sensor. For example, the deposition thickness of the silver paste can be controlled by adjusting the mesh size of the screen and the printing pressure, thereby affecting the resistance value and flexibility of the electrodes. As a preferred implementation manner, the conductive silver paste can be used in combination with flexible substrate materials such as polyimide or thermoplastic polyurethane to improve the flexibility and durability of the overall structure.

[0082] In an alternative embodiment, the semiconductive material of the internal resistance element may be composed of a composite material of carbon nanotubes and a polymer. By adjusting the content of the carbon nanotubes, the resistance value of the semiconductive material can be precisely controlled. The composite material of carbon nanotubes and a polymer can provide adjustable resistance characteristics while maintaining flexibility. The method of adjusting the carbon nanotube content enables the resistance value to be precisely controlled according to application requirements, thereby improving the detection accuracy and reliability of the sensor. This material combination not only addresses the deficiencies of traditional materials in terms of flexibility and resistance control but also meets the precise measurement requirements of flexible pressure sensors within different pressure ranges through precise resistance value regulation. For example, the overall resistance value of the composite material can be adjusted by changing the concentration or distribution pattern of the carbon nanotubes to meet the requirements of different application scenarios. As a preferred implementation method, the solution mixing method can be used to uniformly disperse the carbon nanotubes in the polymer matrix, or the in-situ polymerization method can be used to embed the carbon nanotubes into the polymer chains to form a stable composite material. In addition, the resistance characteristics and flexibility of the composite material can be further optimized by adjusting the length, diameter, and functionalization degree of the carbon nanotubes.

[0083] Furthermore, in an alternative embodiment, for applications that require measuring the pressure on a curved surface, the sensing part 1 can be in a spiral or wavy shape to improve flexibility and conformability. By designing the sensing part 1 in a spiral or wavy shape, the flexible pressure sensor can better conform to the curved surface, improving its application effect on surfaces with complex shapes. This shape design enables the flexible pressure sensor to better adapt to the bending and deformation of the surface when subjected to external pressure, thereby achieving more accurate pressure measurement. The sensing part 1 can use medical-grade silicone as the base material. In actual use, those skilled in the art can use the mold forming technology to make the medical-grade silicone into the required flexible base shape to ensure its close fit with the sensing components. It is also possible to form a thin layer of medical-grade silicone coating on other flexible materials by coating or casting to enhance the flexibility and biocompatibility of the overall structure. In addition, medical-grade silicone can also be used in combination with other functional materials, such as the conductive silver paste or carbon nanotube composite material mentioned above, to further improve the performance and stability of the sensor.

[0084] In summary, the present application forms a multi-segment pressure detection mechanism by adopting internal resistance elements with different contact lengths, thereby improving the accuracy and resolution of pressure detection. At the same time, the use of flexible substrates and sealing materials enables the sensor to have good flexibility, adapt to surfaces of different shapes, and be suitable for application scenarios such as wearable devices. Through the design of the drive circuit, the amplification and digital processing of the pressure signal are realized, ensuring the stability and accuracy of the detection results.

[0085] The preferred specific embodiments of the present application have been described in detail above. Only several implementation manners of the present application are expressed, but it should not be construed as a limitation to the scope of the patent. The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, 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, it should be considered as the scope recorded in this specification. It should be understood that those of ordinary skill in the art can make many modifications and variations according to the concept of the present application without creative labor. Therefore, without departing from the concept of the present application, all technical solutions that can be obtained by those skilled in the art in the technical field according to the concept of the present application through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. A flexible pressure sensor, characterized in that: It comprises a sensing part (1) and a driving circuit; The sensing part (1) comprises: The substrate and sealing material serve as an attachment layer for the semi-conductive material to isolate the outside world; Positive and negative sensing electrodes, made of conductive materials, can be adjusted in flexibility, size, spacing and shape according to application requirements; An internal resistance element, made of a semi-conductive material, is located between the positive and negative sensing electrodes, and the upper and lower electrodes are in contact through the semi-conductive material to form a conduction path; wherein the internal resistance element comprises: a long contact resistance (101), a middle contact resistance (102) and a short contact resistance (103), and the contact lengths of the long contact resistance (101), the middle contact resistance (102) and the short contact resistance (103) are different; and the plurality of internal resistance elements can conduct a circuit by utilizing the force deformation of the flexible pressure sensor: the flexible pressure sensor is deformed according to the pressure it is subjected to and is sequentially connected to the circuit, and the two ends of the sensing part (1) are respectively connected to the driving circuit to provide a voltage source; The driving circuit is connected in sequence with: External power supply; An external resistor (2), wherein the external resistor (2) and the sensing unit (1) together form a voltage divider circuit; An operational amplifier (3), used for amplifying the analog voltage signal output by the sensor unit (1); an analog-to-digital converter (4) for converting the amplified analog voltage signal into a digital voltage signal; A microcontrol unit (5) receives the digital voltage signal from the analog-to-digital converter (4) at its receiving end, calculates the total resistance value of the internal resistance element of the sensing part (1) through the digital voltage signal, and infers the pressure value and change trend of the flexible pressure sensor according to the flexibility coefficient of the positive and negative sensing electrodes; and the output end of the microcontrol unit (5) is connected to an external device for communication.

2. The flexible pressure sensor according to claim 1, characterized in that: The long contact resistor (101) is first connected to the circuit when subjected to pressure, and provides initial pressure information through changes in its own resistance and the relationship between divided voltages.

3. The flexible pressure sensor according to claim 1, characterized in that: The middle contact resistor (102) is connected to the circuit when the pressure reaches a preset threshold, and works in conjunction with the long contact resistor (101) and the short contact resistor (103) to improve the accuracy and resolution of pressure detection.

4. The flexible pressure sensor according to claim 3, characterized in that: The short contact resistor (103) is connected to the circuit when the pressure exceeds the preset threshold, and together with the long contact resistor (101) and the middle contact resistor (102), covers different pressure ranges, thereby ensuring the integrity and accuracy of pressure detection.

5. The flexible pressure sensor according to claim 1, characterized in that: The long contact resistor (101), the middle contact resistor (102) and the short contact resistor (103) are evenly distributed in the sensing part (1), and are in a parallel state when multiple resistors are connected.

6. The flexible pressure sensor according to claim 5, characterized in that: When the sensing part (1) is subjected to pressure, the long contact resistor (101) is first connected to the circuit due to its longer contact. At this time, the total voltage of the flexible pressure sensor is: Where r1 is the total resistance of the long contact resistance in the sensing part, V cc is the voltage connected to the driving circuit, R is the external resistor, and V is the total voltage; When the flexible pressure sensor is continuously subjected to force and the middle contact resistor (102) is connected to the circuit, the total voltage of the flexible pressure sensor is: Wherein, r2 is the total resistance of the middle contact resistance in the sensing part; When the short contact resistor (103) is connected to the circuit, the total voltage of the flexible pressure sensor is: Wherein, r3 is the total resistance of the short contact resistance in the sensing part.

7. The flexible pressure sensor according to claim 1, characterized in that: The positive and negative sensing electrode materials of the flexible pressure sensor are made of conductive silver paste and are manufactured on the flexible base of the substrate by screen printing technology.

8. The flexible pressure sensor according to claim 1, characterized in that: The semiconductive material of the internal resistance element uses a composite material of carbon nanotubes and polymers, and the resistance value of the semiconductive material is precisely controlled by adjusting the content of the carbon nanotubes.

9. The flexible pressure sensor according to claim 1, characterized in that: For applications requiring measurement of pressure on curved surfaces, the sensing portion (1) is spiral or wavy in shape to improve flexibility and conformability.

10. The flexible pressure sensor according to claim 1, characterized in that: The base material uses medical grade silicone.

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