A pressure sensor with both rigidity and flexibility and a preparation method thereof

Abstract

A pressure sensor with both rigidity and flexibility and a preparation method thereof. The present invention relates to a pressure sensor. The purpose of the present invention is to solve the problems such as easy fatigue when facing the need to measure large impact forces in large machinery, and it is difficult for rigid sensors to convert tiny forces into electrical signals, reducing the accuracy and timeliness of work. It includes a rigid carbon fiber plate and a flexible conductive matrix; the first rigid carbon fiber plate, the middle support carbon fiber plate, and the second rigid carbon fiber plate are integrally connected along a straight line direction. The middle support carbon fiber plate is in a serpentine structure, and the flexible conductive matrix is embedded in the gaps of the middle support carbon fiber plate. A first electrode connection hole is processed on the first rigid carbon fiber plate, and a second electrode connection hole is processed on the second rigid carbon fiber plate. An electrode is respectively installed in the first electrode connection hole and the second electrode connection hole. The invention is applied to the technical field of sensors.

Description

Technical Field

[0001] The present invention relates to a pressure sensor, and particularly to a pressure sensor with both rigidity and flexibility and a preparation method thereof. The present invention is applied to the technical field of sensors. Background Art

[0002] With the innovation of preparation technologies and processing means and the proposal of new mechanisms, the types and quality of future flexible materials will achieve a qualitative leap. At the present stage, the flexible sensor technology has also made great progress. Flexible sensors such as piezoresistive, piezoelectric, and capacitive not only have advantages such as high sensitivity and fast response, but also can maintain cyclic stability, and will gradually launch more mature products in application fields such as electronic skin, intelligent robots, human-computer interaction, and medical health monitoring. However, when facing the problem of large mechanical equipment that needs to measure large impact forces, problems such as easy fracture and fatigue of flexible sensors emerge in an endless stream. For example, as introduced in the article: A Flexible Piezoelectret Actuator / Sensor Patch for Mechanical Human-Machine Interfaces (Zhong J, Ma Y, Song Y, et al. ACS Nano, 2019, 13(06): 4007-4013.), in 2019, the team of Professor Li Wei Lin of the University of California, Berkeley successfully developed a flexible thin-film piezoelectric electret actuator / sensor that can be used in a human-computer interaction interface. In the sensor mode, the pressure detection limit is only 1.84 Pa. Future flexible sensors will have higher requirements for technical indicators, functions, and energy consumption. Developing flexible sensors with a large measurement range and high sensitivity will be the research goal and trend in the future. Rigid sensors are often used in heavy machinery, and only when subjected to large impact forces will the sensors produce changes in electrical signals. Under the impact of small forces, the detection of the sensors is negligible, which also makes it difficult for rigid sensors to convert small forces into electrical signals and timely detect small changes in machinery, reducing the accuracy and timeliness of work.

[0003] Although pure nanomaterials, such as silicon (Si), zinc oxide (ZnO), gallium arsenide (GaAs), cadmium selenide (CdSe), etc., can be used as active materials for flexible electronic strain sensor devices, it is difficult to macroscopically integrate pure nanomaterials into an ordered array, which greatly limits the size of flexible electronic strain sensors. As introduced in the article: A flexible and highly pressure-sensitive graphene-polyurethane sponge based on fractured microstructure design. (Yao H B, Ge J, Wang C F, et al. Adv Mater, 2013, 25: 6692-6698), in order to enable the electronic strain sensor to maintain good conductivity under large strains, the organic compounding of elastomers (PDMS, sponge, porous materials) and conductive materials (carbon nanotubes, graphene, carbon black, conductive polymers, metal nanoparticles, metal nanowires, conductive graphite, etc.) is an effective approach. Due to the excellent conductivity and high anisotropy of the elastomer composite structure, it has become a relatively commonly used active material. Commonly used carbon-based materials mainly include recently developed hot low-dimensional materials such as carbon nanotubes and graphene. Due to their characteristics of both conductivity and mechanical flexibility, as well as light weight and stability, they have great potential in the preparation of flexible sensors. As the currently most popular carbon-based material, graphene materials have the characteristics of high sensitivity, good mechanical properties, excellent conductivity, etc., and are a kind of material extremely suitable for preparing flexible strain / stress sensors and are widely studied in the preparation of flexible sensors. For example, Cheng et al. covered the surface of the polymer PDMS with a graphene film in a self-assembled manner and deposited a conductive gold layer. By pre-stretching the sensor, reticular cracks can be generated in the gold layer located on the wrinkled surface, which can improve the linearity of the sensor to 0.9975 [Cheng X, et al. ACS Appl. Mater. Interfaces 2022, 14, 34, 39230–39239]. Therefore, how to select a suitable flexible matrix to cooperate with each other under rigid support to improve the coordination of large measurement ranges and high sensitivities is still a major challenge. Summary of the Invention

[0004] The object of the present invention is to solve the problems in the prior art that when a flexible sensor faces the problem of measuring large impact forces required by large machinery, the flexible sensor is prone to fracture and fatigue, etc., while it is difficult for a rigid sensor to convert a tiny force into an electrical signal and cannot timely detect the tiny changes of the machinery, reducing the accuracy and timeliness of the work, and further provide a pressure sensor with both rigidity and flexibility and a preparation method.

[0005] The technical solution adopted by the present invention to solve the above problems is as follows:

[0006] A pressure sensor with both rigidity and flexibility, which comprises a rigid carbon fiber plate and a flexible conductive matrix;

[0007] The rigid carbon fiber plate includes a first rigid carbon fiber plate, a middle support carbon fiber plate and a second rigid carbon fiber plate; the first rigid carbon fiber plate, the middle support carbon fiber plate and the second rigid carbon fiber plate are integrally connected and arranged in a straight line direction, the middle support carbon fiber plate is in a serpentine structure, the flexible conductive matrix is embedded in the gaps of the middle support carbon fiber plate, a first electrode connection hole is processed on the first rigid carbon fiber plate, a second electrode connection hole is processed on the second rigid carbon fiber plate, and an electrode is installed in each of the first electrode connection hole and the second electrode connection hole.

[0008] Further, the first rigid carbon fiber plate and the second rigid carbon fiber plate have the same structure, and the first rigid carbon fiber plate is made by fixedly connecting a cuboid carbon fiber plate and an arc-shaped convex connecting plate, the arc-shaped convex connecting plate of the first rigid carbon fiber plate is fixedly connected to one end of the middle support carbon fiber plate, and the arc-shaped convex connecting plate of the second rigid carbon fiber plate is fixedly connected to the other end of the middle support carbon fiber plate.

[0009] Further, the flexible conductive matrix includes a plurality of strip-shaped conductive matrices;

[0010] The plurality of strip-shaped conductive matrices are respectively embedded in the gaps on the middle support carbon fiber plate, and the plurality of strip-shaped conductive matrices are arranged in parallel.

[0011] Further, the strip-shaped conductive matrix is made of one or a combination of several materials of carbon-based conductive materials and polymer materials.

[0012] Further, the electrode is a copper wire, and the copper wire is installed at the first electrode connection hole and the second electrode connection hole through conductive silver paste.

[0013] A preparation method of a pressure sensor with both rigidity and flexibility, the method is realized according to the following steps:

[0014] Step 1: Select a carbon fiber plate and place the carbon fiber plate on a laser cutting table, and process and cut the carbon fiber plate through a laser cutting device to obtain the structures of the first rigid carbon fiber plate, the middle support carbon fiber plate and the second rigid carbon fiber plate;

[0015] Step 2: Embed a plurality of flexible conductive matrices in the gaps of the middle support carbon fiber plate, so that the plurality of flexible conductive matrices are embedded in the middle support carbon fiber plate to form a cuboid structure;

[0016] Step Three: Fix the copper wires on the first electrode connection hole of the first rigid carbon fiber plate and the second electrode connection hole of the second rigid carbon fiber plate respectively by winding conductive copper wires, and apply conductive silver paste at the joint of the carbon fiber plate and the copper wire to complete the circuit connection.

[0017] Further, in Step One, the carbon fiber plate is obtained by pretreating and untwisting, cutting the carbon fiber, then impregnating the carbon fiber on an impregnating machine with resin, and then performing curing and cutting operations to obtain a carbon fiber plate with a corresponding thickness.

[0018] Further, in Step Two, the flexible conductive matrix is processed by dropping the solution of the conductive functional layer through a nozzle onto the middle supporting carbon fiber plate, and curing the dropped solution to obtain a flexible matrix film with a target size. The film is stacked by repeatedly dropping and curing, and finally the flexible conductive matrix with the target size is obtained by peeling and cutting.

[0019] Further, the number of times of dropping the solution of the conductive functional layer through the nozzle is at least four times, and the interval time between each dropping is 30 minutes.

[0020] Further, after dropping the solution of the conductive functional layer onto the middle supporting carbon fiber plate in Step Two, the formed specimen is placed on a heating table at 50 °C and heated and dried for 2 hours; then the strip-shaped conductive matrix is placed in an oven for curing treatment at 80 °C for 2 hours.

[0021] Advantages of the present invention:

[0022] When the sensor of the present invention is subjected to external stress or strain, the rigid supporting carbon fiber plate of the sensor resists impact to protect the sensor. The shape of the flexible matrix film covered on one surface and the surface of the flexible matrix in the cutting structure changes, generating microcracks, resulting in changes in the electrical properties of the sensor itself. The combination of rigidity and flexibility brings high sensitivity and large measurement range characteristics to the impact-resistant sensor.

[0023] 1. In terms of performance, a novel large-range and high-sensitivity pressure sensor with both rigidity and flexibility of the present invention can achieve the coordination of high sensitivity and large range, and can further couple high tensile characteristics according to the inherent properties of polymer elastic materials.

[0024] 2. In terms of structure, a novel large-range and high-sensitivity pressure sensor with both rigidity and flexibility of the present invention combines a rigid material, the carbon fiber plate, which can increase the measurement range and resist impact, as a support, and a graphene flexible matrix, which can improve sensitivity and linearity.

[0025] 3. In terms of materials, the rigid-flexible combined pressure sensor of the present invention mainly consists of a rigid material, a carbon fiber board, copper wire electrodes, and a flexible material layer. The winding of the copper wire electrodes can improve the conductive characteristics of the sensor. At the same time, due to the different elastic moduli between different conductive materials, it is also possible to maintain the conductive path under large strains.

[0026] 4. The linear fitting degree of the bionic flexible strain sensor of the present invention within the strain range of 0% - 5% is 0.98282. When the sensor is within the strain range of 10%, the highest linear fitting degree can reach 0.9899. When the sensor strain is within the ranges of 20% and 30% respectively, the linear fitting degree can be increased to 0.9936, indicating that the bionic flexible strain sensor of the present invention has the characteristics of high sensitivity, high linearity, and large strain. Brief Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the pressure sensor of this application.

[0028] Figure 2 It is a schematic diagram of the rigid carbon fiber board.

[0029] Figure 3 It is a schematic diagram of the sensitivity of the pressure sensor of the present invention under 4% tensile strain.

[0030] Figure 4 It is a 10,000-cycle test diagram of the pressure sensor of the present invention under 4% strain.

[0031] Figure 5 It is a tensile cycle test diagram of the pressure sensor of the present invention under 23% strain.

[0032] Figure 6 It is a strain schematic diagram when the pressure sensor is installed on the loading test bench, and the pressure sensor is bent under the loading force, resulting in a change in length. Detailed Embodiments

[0033] Detailed Embodiment 1: In combination with Figure 1 - Figure 2 This embodiment will be described. The pressure sensor with both rigidity and flexibility described in this embodiment includes a rigid carbon fiber board and a flexible conductive matrix;

[0034] The rigid carbon fiber plate includes a first rigid carbon fiber plate 1, a middle support carbon fiber plate 3, and a second rigid carbon fiber plate 13; the first rigid carbon fiber plate 1, the middle support carbon fiber plate 3, and the second rigid carbon fiber plate 13 are integrally connected and arranged in a straight line direction. The middle support carbon fiber plate 3 is in a serpentine structure, and the flexible conductive matrix is embedded at the gaps of the middle support carbon fiber plate 3. A first electrode connection hole 2 is processed on the first rigid carbon fiber plate 1, and a second electrode connection hole 12 is processed on the second rigid carbon fiber plate 13. An electrode is installed on each of the first electrode connection hole 2 and the second electrode connection hole 12.

[0035] Embodiment 2: Combining Figure 1 - Figure 2 To describe this embodiment, for the pressure sensor with both rigidity and flexibility in this embodiment, the first rigid carbon fiber plate 1 and the second rigid carbon fiber plate 13 have the same structure, and the first rigid carbon fiber plate 1 is made by fixedly connecting a cuboid carbon fiber plate and an arc-shaped convex connecting plate. The arc-shaped convex connecting plate of the first rigid carbon fiber plate 1 is fixedly connected to one end of the middle support carbon fiber plate 3, and the arc-shaped convex connecting plate of the second rigid carbon fiber plate 13 is fixedly connected to the other end of the middle support carbon fiber plate 3. Other methods are the same as those in Embodiment 1.

[0036] Embodiment 3: Combining Figure 1 - Figure 2 To describe this embodiment, for the pressure sensor with both rigidity and flexibility in this embodiment, the flexible conductive matrix includes a plurality of strip-shaped conductive matrices;

[0037] The plurality of strip-shaped conductive matrices are respectively embedded at the gaps on the middle support carbon fiber plate 3, and the plurality of strip-shaped conductive matrices are arranged in parallel. The strip-shaped conductive matrix is formed by stacking multiple different material layers, that is, the conductive functional layer is formed by stacking multiple conductive layers, and the number of conductive layers is greater than or equal to four. Other methods are the same as those in Embodiment 2.

[0038] Figure 1 Among them, the first strip-shaped conductive matrix 4, the second strip-shaped conductive matrix 5, the third strip-shaped conductive matrix 6, the fourth strip-shaped conductive matrix 7, the fifth strip-shaped conductive matrix 8, the sixth strip-shaped conductive matrix 9, and the seventh strip-shaped conductive matrix 10 are all strip-shaped conductive matrices with the same structure.

[0039] Embodiment 4: Combining Figure 1 - Figure 2 To describe this embodiment, for the pressure sensor with both rigidity and flexibility in this embodiment, the strip-shaped conductive matrix is made of one material or a combination of two materials selected from carbon-based conductive materials and polymer materials.

[0040] Resin, dispersant, and binder are polymer materials; graphene and carbon nanotube-based materials are carbon-based conductive materials. Other methods are the same as those in Embodiment 2.

[0041] Specific Embodiment Five: Combined with Figure 1 - Figure 2 In this embodiment, for the pressure sensor with both rigidity and flexibility described in this embodiment, the electrode is a copper wire, and the copper wire is installed at the first electrode power connection hole 2 and the second electrode power connection hole 12 through conductive silver paste. Other methods are the same as those in Specific Embodiment One.

[0042] Specific Embodiment Six: Combined with Figure 1 - Figure 2 In this embodiment, for the preparation method of the pressure sensor with both rigidity and flexibility described in this embodiment, the method is realized according to the following steps:

[0043] Step 1: Select a carbon fiber board and place it on the laser cutting table. Process and cut the carbon fiber board through a laser cutting device to obtain the structures of the first rigid carbon fiber board 1, the middle support carbon fiber board 3, and the second rigid carbon fiber board 13;

[0044] The carbon fiber board can be prepared by photolithography, laser processing, or 3D printing.

[0045] Step 2: Install multiple flexible conductive substrates at the gaps of the middle support carbon fiber board 3 so that the multiple flexible conductive substrates are installed in the middle support carbon fiber board 3 to form a cuboid structure;

[0046] The size of the flexible conductive substrate is 20 mm in length, 2 mm in width, and 2 mm in thickness.

[0047] Step 3: Fix the copper wires on the first electrode power connection hole 2 of the first rigid carbon fiber board 1 and the second electrode power connection hole 12 of the second rigid carbon fiber board 13 respectively by winding the conductive copper wires, and apply conductive silver paste at the joint of the carbon fiber board and the copper wires to complete the circuit connection.

[0048] Specific Embodiment Seven: Combined with Figure 1 - Figure 2 In this embodiment, for the preparation method of the pressure sensor with both rigidity and flexibility described in this embodiment, in Step 1, the carbon fiber board is obtained by pretreating and untwisting, cutting the carbon fiber, then impregnating the carbon fiber on an impregnator with resin, and then performing curing and cutting operations to obtain a carbon fiber board with a corresponding thickness. Other methods are the same as those in Specific Embodiment Six.

[0049] Specific Embodiment Eight: Combined with Figure 1 - Figure 2 In this embodiment, for the preparation method of the pressure sensor with both rigidity and flexibility described in this embodiment, in Step 2, the processing of the flexible conductive substrate is to drop the solution of the conductive functional layer into the middle support carbon fiber board 3 through a nozzle, and cure the dropped solution to obtain a flexible matrix film with a target size. The film is stacked by repeatedly dropping and curing, and finally the flexible conductive substrate with the target size is obtained by peeling and cutting. Other methods are the same as those in Specific Embodiment Six.

[0050] Specific implementation method nine: Combination Figure 1 - Figure 2 This embodiment describes a method for preparing a pressure sensor with both rigidity and flexibility. The conductive functional layer solution is dripped at least four times through a drip nozzle, with a 30-minute interval between each drip. The nozzle has a diameter of 1 mm and is 60 mm from the surface of the central supporting carbon fiber plate 3. The remaining method is the same as in Specific Embodiment 8.

[0051] If the conductive functional layer solution is a mixture of at least two materials, including a resin, dispersant, binder, graphene, and carbon nanotubes, magnetic stirring should be performed at room temperature for 20 minutes before use. Place the liquid material in a beaker and place the beaker on a stirring platform at 100 rpm.

[0052] Specific implementation method ten: Combination Figure 1 - Figure 2 This embodiment describes a method for preparing a pressure sensor with both rigidity and flexibility. In step 2, the solution of the conductive functional layer is dripped onto the central supporting carbon fiber plate (3) to form a sample, which is then placed on a heating table at 50°C for 2 hours. The strip-shaped conductive substrate is then placed in an oven for curing at 80°C for 2 hours. The other methods are the same as those in the ninth embodiment.

[0053] In this application, according to the formula GF=(ΔR / R0) / Δε, GF (Gauge Factor) is an indicator to measure the sensitivity of the sensor to the change of physical quantity. The sensitivity of the pressure sensor can be calculated by solving Δε. R0 is the original resistance of the sensor measured by the multimeter when the first electrode connection hole 2 and the second electrode connection hole 12 are not subjected to external force. ΔR is the difference between the resistance value measured in real time and the initial resistance when the sensor is subjected to the loading impact force on the loading test bench. Among them, the length of the sensor is l, and the bending radius of the sensor is R; The curved sheet Figure 6 The corresponding chord length during the test on the loading test bench is C2. The thin sheet is attached to the lower surface of the sensor to provide support and calibration for the sensor test. The corresponding central angle is α. The two equations can be combined to obtain:

[0054] This can be transformed into:

[0055] Define R as the independent variable and get the function F(R)

[0056] Using Taylor expansion to solve when F(R)=0, we have:

[0057]

[0058] Simplified equation:

[0059] f(r)≈f(r k )+f′(r k )(rr k )=0

[0060]

[0061] l2 is the sensor Figure 6 The length value corresponding to the bending state of the impact on the loading impact platform is the limit value, when rk+1-rk satisfies ≤10 -3 When the value is taken as the accuracy, L and c2 are measured in the actual calculation process, so the approximate solution of the bending radius r can be obtained. k As the sensor bending radius value r in the strain calculation, the sensor is Figure 6 The corresponding bending radius of the loading test bench is r, and the sensor is Figure 6 The corresponding chord length when the loading test bench is tested is c1, and the sensor is Figure 6 When the loading test bench is tested, the central angle θ satisfies the following relationship:

[0062]

[0063] Where c1 can be obtained through measurement, and r has been approximated, so the value of θ can be calculated. Therefore, the real-time length of the flexible sensor in the bent state is:

[0064] l = θ × (r + h) where h is known and the sensor thickness is h. Therefore, the length of the bionic sensor 31 in the bent state can be calculated as l. The sensor is fixed at the center of the sheet 32, and the sheet length is L. The sheet is attached to the lower surface of the sensor to provide support and calibration for sensor testing. Therefore, the sensor strain Δε is calculated as:

[0065] Where l1 is the sensor Figure 6 The length of the load impact platform under impact bending state is shown in the figure, and l0 is the length of the sensor under impact bending state. Figure 6 The length of the load impact platform shown is the value when it is initially not stimulated by any external force. θ1 is the length of the sensor when Figure 6 The central angle of the circle corresponding to the bending state of the impact on the loading impact platform is shown in the figure. θ0 is the sensor Figure 6 The central angle of the circle on the loading impact platform shown in the figure is not initially stimulated by any external force, and r1 is the central angle of the sensor at Figure 6 The bending radius corresponding to the bending state of the impact on the loading impact platform is shown, and r0 is the sensor Figure 6The bending radius of the shown loading impact table without any external force excitation initially. Δl is the difference between l1 and l0. Define Figure 6 The height from the neutral layer of the shown sensor to the upper surface of the sensor is z. When the sensor is in an unbent state, r0 approaches infinity at this time, so the equation can be approximately simplified as:

[0066] Since the change in the thickness of this sensor under extremely small strains is very small and can be ignored, only the bending radius corresponding to the bent state needs to be calculated to obtain an approximate value of the strain Δε.

[0067] The above specific implementation can be locally adjusted in different ways by those skilled in the art without departing from the principles and purposes of the present invention. The protection scope of the present invention is subject to the claims and is not limited by the above specific implementation, and all implementation solutions within its scope are subject to the present invention.

Claims

1. A pressure sensor having both rigidity and flexibility, characterized in that: It includes a rigid carbon fiber sheet and a flexible conductive matrix; The rigid carbon fiber plate comprises a first rigid carbon fiber plate (1), a middle supporting carbon fiber plate (3) and a second rigid carbon fiber plate (13); the first rigid carbon fiber plate (1), the middle supporting carbon fiber plate (3) and the second rigid carbon fiber plate (13) are connected as a whole along a straight line direction, the middle supporting carbon fiber plate (3) is a serpentine structure, the flexible conductive matrix is embedded in the gap of the middle supporting carbon fiber plate (3), the first rigid carbon fiber plate (1) is processed with a first electrode connection hole (2), the second rigid carbon fiber plate (13) is processed with a second electrode connection hole (12), and the first electrode connection hole (2) and the second electrode connection hole (12) are respectively installed with an electrode.

2. The rigid and flexible pressure sensor according to claim 1, characterized in that: The first rigid carbon fiber plate (1) and the second rigid carbon fiber plate (13) have the same structure, and the first rigid carbon fiber plate (1) is made of a rectangular carbon fiber plate and an arc-shaped raised connecting plate fixedly connected, the arc-shaped raised connecting plate of the first rigid carbon fiber plate (1) is fixedly connected to one end of the middle supporting carbon fiber plate (3), and the arc-shaped raised connecting plate of the second rigid carbon fiber plate (13) is fixedly connected to the other end of the middle supporting carbon fiber plate (3).

3. The rigid and flexible pressure sensor according to claim 1, characterized in that: The flexible conductive substrate includes a plurality of strip-shaped conductive substrates; The plurality of strip-shaped conductive substrates are respectively embedded in the gaps on the middle supporting carbon fiber plate (3), and the plurality of strip-shaped conductive substrates are arranged in parallel.

4. The rigid and flexible pressure sensor according to claim 1, characterized in that: The strip-shaped conductive matrix is made of one of carbon-based conductive materials and high molecular polymer materials or a combination of the two materials.

5. The rigid and flexible pressure sensor according to claim 1, characterized in that: The electrodes are copper wires, which are installed at the first electrode connection hole (2) and the second electrode connection hole (12) through conductive silver paste.

6. A method for preparing a pressure sensor having both rigidity and flexibility, characterized in that: The method is implemented according to the following steps: Step 1: Select a carbon fiber plate and place the carbon fiber plate on a laser cutting table, and use a laser cutting device to process and cut the carbon fiber plate to obtain a first rigid carbon fiber plate (1), a middle supporting carbon fiber plate (3), and a second rigid carbon fiber plate (13) structure, wherein the first rigid carbon fiber plate (1), the middle supporting carbon fiber plate (3), and the second rigid carbon fiber plate (13) are integrally connected along a straight line direction, and the middle supporting carbon fiber plate (3) is a serpentine structure; Step 2: embedding a plurality of flexible conductive substrates in the gaps of the middle supporting carbon fiber plate (3), so that the plurality of flexible conductive substrates are embedded in the middle supporting carbon fiber plate (3) to form a rectangular parallelepiped structure; Step 3: Use a conductive copper wire winding method to fix the copper wires on the first electrode connection hole (2) of the first rigid carbon fiber plate (1) and the second electrode connection hole (12) of the second rigid carbon fiber plate (13), and apply conductive silver paste at the junction of the carbon fiber plate and the copper wire to complete the circuit connection.

7. The method for preparing a pressure sensor having both rigidity and flexibility according to claim 6, characterized in that: In step 1, the carbon fiber board is pre-treated by untwisting and cutting the carbon fiber, and then the carbon fiber is placed on an impregnation machine for resin impregnation, and then cured and cut to obtain a carbon fiber board of corresponding thickness.

8. The method for preparing a pressure sensor having both rigidity and flexibility according to claim 6, characterized in that: In step 2, the flexible conductive substrate is processed by dripping the solution of the conductive functional layer into the middle supporting carbon fiber plate (3) through a drip nozzle, and curing the dripped solution to obtain a flexible substrate film of the target size, and stacking the films by repeated dripping and curing, and finally peeling and cutting to obtain a flexible conductive substrate of the target size.

9. The method for preparing a pressure sensor having both rigidity and flexibility according to claim 8, characterized in that: The conductive functional layer solution is dripped at least four times through the drip nozzle, and the interval between each dripping is 30 minutes.

10. The method for preparing a pressure sensor having both rigidity and flexibility according to claim 9, characterized in that: In step 2, the solution of the conductive functional layer is dripped onto the middle supporting carbon fiber plate (3) to form a sample, which is then placed on a 50°C heating table for heating and drying for 2 hours; the strip-shaped conductive substrate is then placed in an oven for curing at 80°C for 2 hours.

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