Pressure sensor with rigidity and flexibility and preparation method

Abstract

The invention discloses a pressure sensor with rigidity and flexibility and a preparation method thereof, relates to a pressure sensor, and aims to solve the problems that when a large machine needs to measure large impact force, fatigue is prone to occurring, a rigid sensor is difficult to convert tiny force through an electrical signal, and the impact force cannot be measured easily. The flexible conductive carbon fiber plate comprises a rigid carbon fiber plate and a flexible conductive substrate, wherein the rigid carbon fiber plate is arranged on the flexible conductive substrate; the first rigid carbon fiber plate, the middle supporting carbon fiber plate and the second rigid carbon fiber plate are integrally connected in the linear direction, the middle supporting carbon fiber plate is of a snakelike structure, the flexible conductive substrate is embedded in a gap of the middle supporting carbon fiber plate, a first electrode power connection hole is machined in the first rigid carbon fiber plate, and a second electrode power connection hole is machined in the second rigid carbon fiber plate. A second electrode power connection hole is formed in the second rigid carbon fiber plate, and the first electrode power connection hole and the second electrode power connection hole are each provided with an electrode. The invention is applied to the technical field of sensors.

Description

Technical Field

[0001] The present invention relates to a pressure sensor, and in particular to a pressure sensor having 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 technology and processing methods and the introduction of new mechanisms, the types and quality of flexible materials in the future will make a qualitative leap. At present, flexible sensor technology has also made great progress. Flexible sensors such as piezoresistive, piezoelectric, and capacitive sensors not only have the advantages of high sensitivity and fast response, but also maintain cycle stability. They will gradually launch more mature products in application fields such as electronic skin, intelligent robots, human-machine interaction, and medical health monitoring. However, when facing the problem of large-scale machinery needing to measure large impact forces, flexible sensors are prone to breakage and fatigue. For example, 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.) introduces: In 2019, Professor Lin Liwei's team at the University of California, Berkeley successfully developed a flexible thin film piezoelectric electret actuator / sensor that can be used for human-machine interaction interfaces. The pressure detection limit in sensor mode is only 1.84Pa. In the future, flexible sensors will have higher requirements for technical indicators, functions and energy consumption. The development of flexible sensors with a large range and high sensitivity will be the research goal and trend in the future. Rigid sensors are often used in heavy machinery. They will only produce changes in electrical signals when subjected to large impact forces. Under the impact of smaller forces, the sensor's detection is minimal, which also makes it difficult for rigid sensors to convert tiny forces into electrical signals, and cannot detect small changes in machinery in time, reducing the accuracy and timeliness of work.

[0003] Although pure nanomaterials, such as silicon (Si), zinc oxide (ZnO), gallium arsenide (GaAs) and cadmium selenide (CdSe), can be used as active materials for flexible electronic strain sensors, it is difficult to integrate pure nanomaterials into an ordered array on a macro scale, which greatly limits the size of flexible electronic strain sensors. For example, in the article: A flexible and highly pressure-sensitive graphene-polyurethane sponge based on fractured microstructure design. (Yao HB, Ge J, Wang CF, et al. Adv Mater, 2013, 25: 6692-6698), it is introduced that in order to enable electronic strain sensors to maintain good conductivity under large strain conditions, organically compounding elastomers (PDMS, sponges, porous materials) with conductive materials (carbon nanotubes, graphene, carbon black, conductive polymers, metal nanoparticles, metal nanowires, conductive graphite, etc.) is an effective way. Due to the excellent conductivity and high anisotropy of the elastomer composite structure, it has become a commonly used active material. Commonly used carbon-based materials include low-dimensional materials such as carbon nanotubes and graphene, which have been hotly developed in recent years. Due to their electrical conductivity, mechanical flexibility, light weight and stability, they have great potential in the preparation of flexible sensors. As the most popular carbon-based material at present, graphene material has the characteristics of high sensitivity, good mechanical properties and excellent electrical conductivity. It is a material that is very suitable for preparing flexible strain / stress sensors. It has been widely studied in the preparation of flexible sensors. For example, Cheng et al. covered the surface of polymer PDMS with graphene film in a self-assembled manner and deposited a conductive gold layer. By pre-stretching the sensor, the gold layer on the wrinkled surface can produce a mesh crack, which can improve the linearity of the sensor to 0.9975 [ChengX, et al. ACSAppl.Mater.Interfaces2022,14,34,39230–39239]. Therefore, how to select a suitable flexible substrate under rigid support to cooperate with each other to improve the synergy of large range and high sensitivity is still a major challenge. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that flexible sensors in the prior art are prone to breakage and fatigue when facing the need to measure large impact forces in large machinery, while rigid sensors find it difficult to convert tiny forces into electrical signals and cannot detect tiny changes in the machinery in time, thereby reducing the accuracy and timeliness of the work. A pressure sensor with both rigidity and flexibility and a preparation method are provided.

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

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

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

[0008] Furthermore, 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 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 is fixedly connected to one end of the middle supporting carbon fiber plate, and the arc-shaped raised connecting plate of the second rigid carbon fiber plate is fixedly connected to the other end of the middle supporting carbon fiber plate.

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

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

[0011] Furthermore, the strip-shaped conductive substrate is made of one material or a combination of several materials selected from the group consisting of carbon-based conductive materials and high molecular polymer materials.

[0012] Furthermore, 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 method for preparing a pressure sensor having both rigidity and flexibility is implemented 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 use a laser cutting device to process and cut the carbon fiber plate to obtain a first rigid carbon fiber plate, a middle supporting carbon fiber plate, and a second rigid carbon fiber plate structure;

[0015] Step 2: embedding a plurality of flexible conductive substrates in the gaps of the middle supporting carbon fiber plate, so that the plurality of flexible conductive substrates are embedded in the middle supporting carbon fiber plate to form a rectangular parallelepiped structure;

[0016] Step 3: Use conductive copper wire winding to fix the copper wire on the first electrode connection hole of the first rigid carbon fiber board and the second electrode connection hole of the second rigid carbon fiber board, and apply conductive silver paste at the junction of the carbon fiber board and the copper wire to complete the circuit connection.

[0017] Furthermore, in step 1, the carbon fiber board is prepared by pre-treating the carbon fiber by untwisting and cutting, and then placing the carbon fiber on an impregnating machine for resin impregnation, and then performing curing and cutting operations to obtain a carbon fiber board of corresponding thickness.

[0018] Furthermore, 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 through a dropper, and curing the dripped solution to obtain a flexible substrate film of a target size, and stacking the film by repeated dripping and curing, and finally obtaining a flexible conductive substrate of a target size by peeling and cutting.

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

[0020] Furthermore, in step 2, the solution of the conductive functional layer is dripped onto the middle supporting carbon fiber board to form a sample, which is then placed on a 50°C heating table for heating and drying for 2 hours; then the strip-shaped conductive substrate is placed in an oven for curing treatment at 80°C for 2 hours.

[0021] Beneficial effects 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 and protects the sensor, and the shape of the flexible substrate film covered on one surface and the flexible substrate surface in the cutting structure changes, generating micro cracks, resulting in changes in the electrical properties of the sensor itself. The combination of rigidity and flexibility provides a sensor with impact resistance, high sensitivity and a large range of characteristics.

[0023] 1. In terms of performance, the novel large-range, high-sensitivity pressure sensor of the present invention, which is both rigid and flexible, can achieve the synergy of high sensitivity and large range, and can couple high tensile properties based on the inherent properties of polymer elastic materials.

[0024] 2. Structurally, the novel large-range, high-sensitivity pressure sensor of the present invention, which is both rigid and flexible, combines a rigid carbon fiber plate as a support that can improve the range and resist impact, and a graphene flexible matrix that can improve sensitivity and linearity.

[0025] 3. In terms of materials, the rigid-flexible pressure sensor of the present invention is mainly composed of a rigid carbon fiber plate, a copper wire electrode, and a flexible material layer. The copper wire electrode winding can improve the conductivity of the sensor, and because the elastic modulus of different conductive materials is different, it can also allow the conductive path to be maintained under large strain.

[0026] 4. The linear fit of the bionic flexible strain sensor of the present invention is 0.98282 in the strain range of 0%-5%. When the sensor is in the strain range of 10%, the linear fit can reach up to 0.9899, ​​and when the sensor strain is in the range of 20% and 30%, the linear fit can be improved to 0.9936, indicating that the bionic flexible strain sensor of the present invention has high sensitivity, high linearity and large strain characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the pressure sensor for this application.

[0028] Figure 2 Schematic diagram of a rigid carbon fiber plate.

[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 This is a test chart of the pressure sensor of the present invention after 10,000 cycles under 4% strain.

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

[0032] Figure 6 This is a schematic diagram of the strain when the pressure sensor is installed on the loading test bench and the pressure sensor is subjected to the loading force, causing it to bend and its length to change. DETAILED DESCRIPTION

[0033] Specific implementation method 1: Combination Figure 1-Figure 2 The present embodiment is described as follows: a pressure sensor having both rigidity and flexibility comprises a rigid carbon fiber plate and a flexible conductive substrate;

[0034] The rigid carbon fiber plate includes 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 integrally connected in a straight line direction, the middle supporting carbon fiber plate 3 is a serpentine structure, and 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, and the second rigid carbon fiber plate 13 is processed with a second electrode connection hole 12. The first electrode connection hole 2 and the second electrode connection hole 12 are respectively installed with an electrode.

[0035] Specific implementation method 2: Combination Figure 1-Figure 2 This embodiment is described. In this embodiment, a pressure sensor having both rigidity and flexibility is described. The first rigid carbon fiber plate 1 and the second rigid carbon fiber plate 13 have the same structure. The first rigid carbon fiber plate 1 is made by fixing a rectangular carbon fiber plate and an arc-shaped raised connecting plate. 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. Other methods are the same as those in the first embodiment.

[0036] Specific implementation method three: Combination Figure 1-Figure 2 This embodiment is described. In this embodiment, a pressure sensor having both rigidity and flexibility is described. The flexible conductive substrate includes a plurality of strip-shaped conductive substrates.

[0037] Multiple strip-shaped conductive substrates are respectively embedded in the gaps on the middle supporting carbon fiber plate 3, and multiple strip-shaped conductive substrates are arranged in parallel. The strip-shaped conductive substrate is formed by stacking multiple layers of different materials, 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 the second specific implementation method.

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

[0039] Specific implementation method four: Combination Figure 1-Figure 2 The present embodiment is described as a pressure sensor having both rigidity and flexibility, wherein the strip-shaped conductive substrate is made of one material or a combination of two materials selected from the group consisting of a carbon-based conductive material and a high molecular polymer material.

[0040] The resin, dispersant and binder are high molecular polymer materials; the graphene and carbon nanotube materials are carbon conductive materials. The other methods are the same as those in the second embodiment.

[0041] Specific implementation method five: Combination Figure 1-Figure 2 This embodiment describes a pressure sensor with both rigidity and flexibility, wherein 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. Other methods are the same as those in the first embodiment.

[0042] Specific implementation method six: Combination Figure 1-Figure 2 This embodiment describes a method for preparing a pressure sensor having both rigidity and flexibility, and the method is implemented according to the following steps:

[0043] Step 1: Select a carbon fiber plate and place it 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;

[0044] Carbon fiber plates can be prepared by photolithography, laser processing or 3D printing.

[0045] 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;

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

[0047] Step 3: Use conductive copper wire winding to fix the copper wire on the first electrode connection hole 2 of the first rigid carbon fiber board 1 and the second electrode connection hole 12 of the second rigid carbon fiber board 13, and apply conductive silver paste at the junction of the carbon fiber board and the copper wire to complete the circuit connection.

[0048] Specific implementation method seven: Combination Figure 1-Figure 2 This embodiment is described. In the method for preparing a pressure sensor with both rigidity and flexibility, in step 1, the carbon fiber sheet is pre-treated by untwisting and cutting the carbon fiber, and then the carbon fiber is placed on an impregnator for resin impregnation, and then cured and cut to obtain a carbon fiber sheet of corresponding thickness. The other methods are the same as those in the sixth embodiment.

[0049] Specific implementation method eight: Combination Figure 1-Figure 2 This embodiment is described. In the method for preparing a pressure sensor with both rigidity and flexibility described in this embodiment, the flexible conductive substrate processing in step 2 is to drip the solution of the conductive functional layer into the middle supporting carbon fiber plate 3 through a drip nozzle, and solidify the dripped solution to obtain a flexible substrate film of a target size, and to stack the films by repeated dripping and solidification, and finally to obtain a flexible conductive substrate of a target size by peeling and cutting. Other methods are the same as those in the specific embodiment 6.

[0050] Specific implementation method nine: Combination Figure 1-Figure 2 This embodiment is described. In the method for preparing a pressure sensor with both rigidity and flexibility, the number of times the solution of the conductive functional layer is dripped through the drip nozzle is at least four times, and the interval between each dripping is 30 minutes. The diameter of the drip nozzle is 1 mm, and the distance between the drip nozzle and the surface of the middle supporting carbon fiber plate 3 is 60 mm. The other methods are the same as those of the specific embodiment eight.

[0051] If the solution of the conductive functional layer is a mixed solution of at least two materials including resin, dispersant, binder, graphene, and carbon nanotubes, it needs to be magnetically stirred for 20 minutes at room temperature before use. Place the liquid material in a beaker, and place the beaker on a stirring table with a stirring speed of 100 rpm.

[0052] Specific implementation method ten: Combination Figure 1-Figure 2 This embodiment is described. In the 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 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; and then the strip-shaped conductive substrate is placed in an oven for curing at 80°C for 2 hours. 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, and 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 when the loading test bench is tested 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 are 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 precision, 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 load test bench is r. Figure 6 The corresponding chord length when the load 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 relationship:

[0062]

[0063] Among them, c1 can be obtained by measurement, and r has been approximated, so the value of θ can be calculated. So at this time, 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. The length of the sheet is L. The sheet is attached to the lower surface of the sensor to provide support and calibration for the sensor test. 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 in the figure is the initial length without any external force excitation. θ1 is the length of the sensor at Figure 6 The central angle of the circle corresponding to the bending state under impact on the loading impact platform shown in the figure is θ0, which 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 sensor Figure 6 The bending radius corresponding to the bending state of the impact on the loading impact platform is shown in the figure, and r0 is the sensor Figure 6The bending radius of the loading impact table is shown without any external force excitation. Δl is the difference between l1 and l0. Definition Figure 6 The height from the neutral layer of the sensor to the upper surface of the sensor is z. When the sensor is in an unbent state, r0 approaches infinity, so the equation can be approximately simplified to:

[0066] Because the change in the thickness of the sensor under extremely small strain is very small and can be ignored, it is only necessary to calculate the corresponding bending radius under the bending state to obtain the approximate value of the strain Δε.

[0067] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of 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 and arranged in a straight line, 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. A pressure sensor having both rigidity and flexibility 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 by fixedly connecting a rectangular carbon fiber plate and an arc-shaped raised connecting plate, 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 pressure sensor having both rigidity and flexibility according to claim 1, characterized in that: The flexible conductive substrate comprises a plurality of strip-shaped conductive substrates; A 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 pressure sensor having both rigidity and flexibility according to claim 1, characterized in that: The strip-shaped conductive substrate is made of one material selected from carbon-based conductive materials and high molecular polymer materials or a combination of the two materials.

5. The pressure sensor having both rigidity and flexibility 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; 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 board (1) and the second electrode connection hole (12) of the second rigid carbon fiber board (13), and apply conductive silver paste at the junction of the carbon fiber board and the copper wire to complete the circuit connection.

7. A 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 prepared by pre-treating the carbon fiber by untwisting and cutting, and then placing the carbon fiber on an impregnating machine for resin impregnation, and then performing curing and cutting operations 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 a target size, and by repeatedly dripping and curing the film is stacked, and finally by peeling and cutting to obtain a flexible conductive substrate of a 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 2 hours; and the strip-shaped conductive substrate is then placed in an oven for curing at 80° C. for 2 hours.

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