Flexible pressure sensor and manufacturing method therefor

Abstract

Disclosed in the present invention are a flexible pressure sensor and a manufacturing method therefor. The flexible pressure sensor successively comprises, from top to bottom, a substrate layer, a conductive pressure-sensitive layer, an encapsulation layer and an electrode layer . On the basis of the substrate layer, the conductive pressure-sensitive layer is formed by a conductive elastomer having a spatial pore structure, the spatial pore structure being in a circular or irregular shape, and the size range of the spatial pore structure being from 100 microns to 500 microns. The conductive elastomer is obtained by mixing a preset proportion of high-boiling-point solution and low-boiling-point solution to dissolve an elastomer, and then adding a conductive filler. The encapsulation layer combines the conductive pressure-sensitive layer and the electrode layer. The flexible sensor provided by the present invention can sense slight forces, and give obvious feedback on Pa-level forces.

Description

A flexible pressure sensor and its preparation method Technical Field

[0001] The present invention relates to the field of flexible sensors, and in particular to a flexible pressure sensor and a preparation method thereof. Background Art

[0002] Flexible pressure sensors offer advantages over traditional rigid sensors, such as softness, lightness, and bend resistance. They are crucial for force monitoring in wearables, biomedicine, human-computer interaction, and other fields. Currently, the detection limit of flexible sensors is generally in the kPa range, making it difficult to detect smaller forces. This significantly limits dynamic monitoring under minimal forces.

[0003] Existing technologies for fabricating flexible sensors primarily include microstructure transfer, surface modification, and microcrack creation. However, most flexible sensors currently have detection limits limited to the kPa range, making them incapable of accurately sensing even smaller forces. This significantly limits force measurement under low-force conditions. Therefore, a flexible sensor capable of sensing even small forces is needed.

[0004] Summary of the Invention

[0005] The present invention provides a flexible pressure sensor and a preparation method thereof. The flexible sensor can realize obvious feedback of Pa-level force.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a flexible pressure sensor, which includes, from top to bottom, a base layer, a conductive pressure-sensitive layer, an encapsulation layer and an electrode layer; the conductive pressure-sensitive layer is based on the base layer and is composed of a conductive elastomer with a spatial pore structure; wherein the shape of the spatial pore structure is circular or irregular; the size of the spatial pore structure ranges from 100 microns to 500 microns; the conductive elastomer is obtained by mixing a high-boiling point solution and a low-boiling point solution in a preset proportion to dissolve the elastomer, and then adding a conductive filler; the encapsulation layer combines the conductive pressure-sensitive layer and the electrode layer.

[0007] Furthermore, the base layer is one of PC film, PVC film, PET film, PP film, PS film, PI film, PMMA film and PEEK film.

[0008] Furthermore, one or both sides of the base layer are frosted.

[0009] It can be understood that the frosted structure increases the contact surface area between the conductive pressure-sensitive layer and the base layer, thereby making the bond between the two layers stronger.

[0010] Furthermore, the low boiling point solution is one or more of tetrahydrofuran, acetone, butanone, dichloroethane, and isopropanol, and the high boiling point solution is one or more of N,N-dimethylformamide, toluene, chlorobenzene, xylene, and cyclohexanone.

[0011] It can be understood that the low-boiling-point solvent evaporates quickly during the elastomer solution spraying process, causing the elastomer solute to solidify quickly. During the spraying process, the small droplets gradually accumulate to form a spatial pore structure. The high-boiling-point solvent is deposited in the lower layer, and the elastomer solute slowly solidifies to achieve a close bond with the substrate material.

[0012] Furthermore, the elastomer is one or more of TPU, TPE, SBS, SEBS, and SEPS.

[0013] It can be understood that low-modulus elastomeric materials construct a spatial pore structure. Under extremely small forces, the spatial pore structure constructed by the elastomer can undergo large deformation, resulting in more overlapping conductive paths, thereby causing obvious changes in electrical signals, which can detect the force conditions.

[0014] Furthermore, the conductive filler is one or more of carbon nanotubes, carbon black, graphite, and graphene; and the mass of the conductive filler is 0.2-40 mg / mL.

[0015] Furthermore, the volume ratio of the high boiling point solution to the low boiling point solution is 1:1-1:10.

[0016] Furthermore, the high boiling point solution and the low boiling point solution are mixed in a preset ratio to dissolve the elastomer, and the concentration of the solution obtained is 0.2-100 mg / mL.

[0017] Furthermore, the encapsulation layer is liquid glue.

[0018] It is understandable that the liquid glue is mainly liquid silicone. The encapsulation layer after curing at room temperature can keep the distance between the conductive layer and the electrode layer stable, ensuring the data consistency of each test.

[0019] Furthermore, the electrode layer is a flexible FPC or a conductive path made by screen printing.

[0020] Accordingly, an embodiment of the present invention further provides a method for preparing a flexible pressure sensor, comprising:

[0021] Obtaining a base layer of a preset size, and cleaning the surface of the base layer using a plasma cleaning machine;

[0022] Mixing a high boiling point solution and a low boiling point solution in a preset ratio to dissolve the elastomer, and adding a conductive filler to obtain a conductive elastomer solution;

[0023] Heating the base layer and uniformly spraying the conductive elastomer solution onto the base layer by ultrasonic spraying to obtain a conductive pressure-sensitive layer;

[0024] The conductive pressure-sensitive layer and the electrode layer are packaged with liquid glue to obtain a flexible pressure sensor.

[0025] It is understandable that, compared to the prior art, the present invention achieves stepped volatilization of the elastomer solution by configuring a multi-solvent system with high and low boiling points, thereby realizing the spatial pore structure of the elastomer. The low-boiling-point solvent evaporates rapidly during the spraying process of the elastomer solution, causing the elastomer solute to solidify rapidly, and gradually accumulates into a spatial pore structure in the form of fine droplets during the spraying process. The high-boiling-point solvent is deposited in the lower layer, and the elastomer solute slowly solidifies to achieve a close bond with the substrate material. In addition, when a spatial pore structure is constructed with a low-modulus elastomer material, the spatial pore structure constructed by the elastomer can undergo a large deformation under extremely small stress, resulting in more overlapping conductive paths, thereby causing obvious changes in electrical signals, and the stress condition can be detected. The spatial pore structure constructed by ultrasonic spraying has finer pore walls, which are easier to deform than coarse pore walls under small pressure. The encapsulation layer can keep the distance between the conductive pressure-sensitive layer and the electrode layer stable, ensuring data consistency for each test. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic structural diagram of a flexible pressure sensor provided by an embodiment of the present invention;

[0027] FIG2 is a graph showing the change in I / R versus time of a sensor under 3 Pa pressure loading and unloading provided by an embodiment of the present invention;

[0028] FIG3 is a scanning electron microscope image of a flexible pressure sensor provided by an embodiment of the present invention;

[0029] FIG4 is a scanning electron microscope image of a flexible pressure sensor provided in a comparative example of the present invention;

[0030] FIG5 is a curve showing the change in 1 / R of the sensor over time under 3 Pa pressure loading and unloading provided in a comparative example of the present invention. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] It should be noted that the boiling point of the present invention is limited to 100° C. If the boiling point of a solution is higher than 100° C., it is determined to be a high-boiling-point solution; if the boiling point of a solution is lower than 100° C., it is determined to be a low-boiling-point solution.

[0033] Example 1

[0034] Please refer to Figure 1, which is a structural schematic diagram of a flexible pressure sensor provided by an embodiment of the present invention, which includes, from top to bottom, 1: a base layer, 2: a conductive pressure-sensitive layer, 3: an encapsulation layer, and 4: an electrode layer; the conductive pressure-sensitive layer is based on the base layer and is composed of a conductive elastomer with a spatial pore structure; wherein the shape of the spatial pore structure is circular or irregular; the size of the spatial pore structure ranges from 100 microns to 500 microns; the conductive elastomer is obtained by mixing a high-boiling point solution and a low-boiling point solution in a preset proportion to dissolve the elastomer, and then adding a conductive filler; the encapsulation layer combines the conductive pressure-sensitive layer and the electrode layer.

[0035] In this embodiment, the base layer is one of PC film, PVC film, PET film, PP film, PS film, PI film, PMMA film, and PEEK film; the thickness of the base layer is 0.025-0.3 mm, preferably 0.1 mm; one or both sides of the base are frosted structures, and the frosted structures include but are not limited to regular and irregular structures.

[0036] It can be understood that the frosted structure increases the contact surface area between the conductive pressure-sensitive layer and the base layer, thereby making the bond between the two layers stronger.

[0037] In this embodiment, the low boiling point solution is one or more of tetrahydrofuran, acetone, butanone, dichloroethane, and isopropyl alcohol, and the high boiling point solution is one or more of N,N-dimethylformamide, toluene, chlorobenzene, xylene, and cyclohexanone.

[0038] It can be understood that the low-boiling-point solvent evaporates quickly during the elastomer solution spraying process, causing the elastomer solute to solidify quickly. During the spraying process, the small droplets gradually accumulate to form a spatial pore structure. The high-boiling-point solvent is deposited in the lower layer, and the elastomer solute slowly solidifies to achieve a close bond with the substrate material.

[0039] In this embodiment, the elastomer is one or more of TPU, TPE, SBS, SEBS, and SEPS.

[0040] It is understandable that low modulus elastomeric materials construct a spatial pore structure. Under extremely small forces, the spatial pore structure constructed by the elastomer can undergo large deformation, resulting in more overlapping conductive paths, thereby causing obvious changes in electrical signals, which can detect the force conditions.

[0041] In this embodiment, the conductive filler is one or more of carbon nanotubes, carbon black, graphite, and graphene; and the mass of the conductive filler is 0.2-40 mg / mL.

[0042] In this embodiment, the high boiling point solution and the low boiling point solution are mixed in a preset ratio to dissolve the elastomer, and the concentration of the solution obtained is 0.2-100 mg / mL.

[0043] In this embodiment, the packaging layer is liquid glue; the electrode layer is a flexible FPC or a conductive path made by screen printing.

[0044] It should be noted that the liquid glue is mainly liquid silicone, which cures at room temperature and forms a silicone rubber elastomer. The encapsulation layer is encapsulated according to fixed dispensing parameters and pressing force, with a thickness of 0.05-0.1mm, preferably 0.05mm.

[0045] As a preferred solution, the base layer is a single-sided frosted PET film with a thickness of 0.1 mm and a size of 150*150 mm. 2 .

[0046] As a preferred embodiment, the elastomer is SEBS; the conductive filler is carbon black; the high-boiling-point solution is chlorobenzene; the low-boiling-point solution is tetrahydrofuran; the volume ratio of the high-boiling-point solution to the low-boiling-point solution is 1:10; the concentration of the solution obtained by mixing and dissolving the elastomer with the high-boiling-point solution and the low-boiling-point solution in a preset proportion is 80 mg / mL; the encapsulation layer is liquid glue; and the electrode layer is a flexible FPC or a conductive path made by screen printing.

[0047] As a preferred solution, the flexible pressure sensor in this embodiment is prepared by the following steps:

[0048] S101: Use a plasma cleaning machine to clean the substrate surface. The plasma cleaning machine uses one of the following gases: air, nitrogen, and carbon dioxide. The cleaning power is 200-400w, the gas pressure is 50-200Pa, and the processing time is 100-400s.

[0049] S102: Mix the high-boiling point solution and the low-boiling point solution in a volume ratio of 1:10, then add the elastomer to the mixed solution to prepare an 80 mg / mL solution, and use room temperature or heating and stirring to completely dissolve the elastomer. If heating and stirring are used, the heating temperature is 50-80°C and the stirring speed is 300-1000 rpm / min. Then add carbon black to the above solution to prepare a 20 mg / mL conductive elastomer solution. Use a high-speed disperser to disperse and mix for 0.5-2 hours at a speed of 5000-10000 rpm / min. After being fully mixed, set aside for later use.

[0050] S103: Fix the substrate material on a flat heating table at a heating temperature of 60-120°C and use an ultrasonic sprayer (Oriental Jinrong, UC360c) to ultrasonically spray the solution. Add the conductive elastomer solution into the sprayer and spray at a rate of 0.07-0.12 mL / cm2 per area of ​​the substrate membrane. 2 Spray the conductive elastomer solution evenly on the base film. After spraying the conductive elastomer solution, spray the solvent in the solution on the surface at a spraying rate of 0.02-0.05mL / cm 2 , so that the elastic body is tightly connected. The amount of conductive elastomer solution used is 0.089mL / cm 2 Continue heating for 5-10 minutes, and then remove the conductive elastomer film after the solvent has completely evaporated.

[0051] S104: Cut the prepared conductive elastomer film into a specific shape to match the electrode layer. Encapsulate the conductive layer and the electrode layer using liquid glue. Apply the liquid glue evenly around the electrode layer. Then, completely cover the cut conductive layer on the electrode layer and wait for 30-60 minutes for the glue to fully cure, resulting in a flexible pressure sensor with a spatial pore structure on the surface.

[0052] As a preferred embodiment, please refer to Figure 2, which shows the sensor I / R versus time curve under 3Pa pressure loading and unloading, according to an embodiment of the present invention. When loading and unloading a 3Pa load, the flexible pressure sensor exhibits a clear signal response. Please refer to Figure 3, which shows a scanning electron micrograph of a flexible pressure sensor according to an embodiment of the present invention. It can be seen that the flexible pressure sensor fabricated using the preparation method provided by the embodiment of the present invention has a spatial pore structure, enabling rapid sensing of deformation caused by slight forces.

[0053] The present invention achieves a stepped volatilization of the elastomer solution by configuring a multi-solvent system with high and low boiling points, thereby realizing the spatial pore structure of the elastomer. The low-boiling-point solvent evaporates rapidly during the spraying process of the elastomer solution, causing the elastomer solute to solidify rapidly, and gradually accumulates into a spatial pore structure in the form of fine droplets during the spraying process. The high-boiling-point solvent is deposited in the lower layer, and the elastomer solute slowly solidifies to achieve a close bond with the substrate material. In addition, when a low-modulus elastomer material is used to construct a spatial pore structure, the spatial pore structure constructed by the elastomer can undergo a large deformation under extremely small stress, resulting in more overlapping conductive paths, thereby causing obvious changes in electrical signals, and the stress condition can be detected. The spatial pore structure constructed by ultrasonic spraying has finer pore walls, which are easier to deform than coarse pore walls under small pressure. The encapsulation layer can keep the distance between the conductive pressure-sensitive layer and the electrode layer stable, ensuring the consistency of data in each test. The flexible pressure sensor provided by the present invention can achieve a lower detection limit and complete the identification of Pa-level pressure.

[0054] Example 2

[0055] Please refer to Figure 1, which is a structural schematic diagram of a flexible pressure sensor provided by an embodiment of the present invention, which includes, from top to bottom, 1: a base layer, 2: a conductive pressure-sensitive layer, 3: an encapsulation layer, and 4: an electrode layer; the conductive pressure-sensitive layer is based on the base layer and is composed of a conductive elastomer with a spatial pore structure; wherein the shape of the spatial pore structure is circular or irregular; the size of the spatial pore structure ranges from 100 microns to 500 microns; the conductive elastomer is obtained by mixing a high-boiling point solution and a low-boiling point solution in a preset proportion to dissolve the elastomer, and then adding a conductive filler; the encapsulation layer combines the conductive pressure-sensitive layer and the electrode layer.

[0056] As a preferred solution, the base layer is a single-sided frosted PET film with a thickness of 0.1 mm and a size of 150*150 mm. 2 .

[0057] As a preferred embodiment, the elastomer is SEBS; the conductive filler is carbon black; the high-boiling-point solution is chlorobenzene; the low-boiling-point solution is tetrahydrofuran; the volume ratio of the high-boiling-point solution to the low-boiling-point solution is 1:10; the concentration of the solution obtained by mixing and dissolving the elastomer with the high-boiling-point solution and the low-boiling-point solution in a preset proportion is 80 mg / mL; the encapsulation layer is liquid glue; and the electrode layer is a flexible FPC or a conductive path made by screen printing.

[0058] As a preferred solution, the flexible pressure sensor in this embodiment is prepared by the following steps:

[0059] S201: Use a plasma cleaning machine to clean the substrate surface. The plasma cleaning machine uses one of the following gases: air, nitrogen, and carbon dioxide. The cleaning power is 200-400w, the gas pressure is 50-200Pa, and the processing time is 100-400s.

[0060] S202: Mix the high-boiling point solution and the low-boiling point solution in a volume ratio of 1:10, then add the elastomer to the mixed solution to prepare an 80 mg / mL solution, and use room temperature or heating and stirring to completely dissolve the elastomer. If heating and stirring are used, the heating temperature is 50-80°C and the stirring speed is 300-1000rpm / min. Then add carbon black to the above solution to prepare a 20 mg / mL conductive elastomer solution. Use a high-speed disperser to disperse and mix for 0.5-2 hours at a speed of 5000-10000rpm / min. After being fully mixed, set aside for later use.

[0061] S203: Fix the substrate material on a flat heating table, heat it to 60-120°C, and use an ultrasonic sprayer (Oriental Jinrong, UC360c) to ultrasonically spray the solution. Add the conductive elastomer solution into the sprayer and spray it at a rate of 0.07-0.12 mL / cm2 per area of ​​the substrate membrane. 2 Spray the conductive elastomer solution evenly on the base film. After spraying the conductive elastomer solution, spray the solvent in the solution on the surface at a spraying rate of 0.02-0.05mL / cm 2 , so that the elastic body is tightly connected. The amount of conductive elastomer solution used is 0.12mL / cm 2 Continue heating for 5-10 minutes, and then remove the conductive elastomer film after the solvent has completely evaporated.

[0062] S204: Cut the prepared conductive elastomer film into a specific shape to match the electrode layer. Encapsulate the conductive layer and the electrode layer using liquid glue. Apply the liquid glue evenly around the electrode layer. Then, completely cover the cut conductive layer on the electrode layer and wait for 30-60 minutes for the glue to fully cure, thereby obtaining a flexible pressure sensor with a spatial pore structure on the surface.

[0063] The present invention mixes a high-boiling point solution and a low-boiling point solution in a preset ratio to dissolve the elastomer, thereby realizing a spatial pore structure capable of sensing slight force deformation. The low-boiling point solvent evaporates rapidly during the spraying process of the elastomer solution, causing the elastomer solute to solidify rapidly, and gradually accumulates into a spatial pore structure in the form of fine droplets during the spraying process. The high-boiling point solvent is deposited in the lower layer, and the elastomer solute slowly solidifies to achieve a close bond with the substrate material. Using ultrasonic spraying instead of traditional carrier gas spraying is more advantageous for constructing a spatial void structure, and can spray out finer droplets to form finer pore walls. At the same time, under extremely small force conditions, the spatial pore structure constructed by the elastomer can undergo large deformation, resulting in more overlapping conductive paths, resulting in obvious electrical signal changes, and the force conditions can be detected. The flexible sensor provided by the present invention can sense slight forces and provide obvious feedback on Pa-level forces.

[0064] Example 3

[0065] Please refer to Figure 1, which is a structural schematic diagram of a flexible pressure sensor provided by an embodiment of the present invention, which includes, from top to bottom, 1: a base layer, 2: a conductive pressure-sensitive layer, 3: an encapsulation layer, and 4: an electrode layer; the conductive pressure-sensitive layer is based on the base layer and is composed of a conductive elastomer with a spatial pore structure; wherein the shape of the spatial pore structure is circular or irregular; the size of the spatial pore structure ranges from 100 microns to 500 microns; the conductive elastomer is obtained by mixing a high-boiling point solution and a low-boiling point solution in a preset proportion to dissolve the elastomer, and then adding a conductive filler; the encapsulation layer combines the conductive pressure-sensitive layer and the electrode layer.

[0066] As a preferred solution, the base layer is a single-sided frosted PET film with a thickness of 0.1 mm and a size of 150*150 mm. 2 .

[0067] As a preferred embodiment, the elastomer is SEBS; the conductive filler is carbon nanotubes; the high-boiling-point solution is chlorobenzene; the low-boiling-point solution is tetrahydrofuran; the volume ratio of the high-boiling-point solution to the low-boiling-point solution is 1:10; the concentration of the solution obtained by mixing and dissolving the elastomer with the high-boiling-point solution and the low-boiling-point solution in a preset proportion is 80 mg / mL; the encapsulation layer is liquid glue; and the electrode layer is a flexible FPC or a conductive path made by screen printing.

[0068] As a preferred solution, the flexible pressure sensor in this embodiment is prepared by the following steps:

[0069] S301: Use a plasma cleaning machine to clean the substrate surface. The plasma cleaning machine uses one of the following gases: air, nitrogen, and carbon dioxide. The cleaning power is 200-400w, the gas pressure is 50-200Pa, and the processing time is 100-400s.

[0070] S302: Mix the high-boiling point solution and the low-boiling point solution in a volume ratio of 1:10, then add the elastomer to the mixed solution to prepare an 80 mg / mL solution, and use room temperature or heating and stirring to completely dissolve the elastomer. If heating and stirring are used, the heating temperature is 50-80°C and the stirring speed is 300-1000rpm / min. Then add carbon nanotubes to the above solution to prepare a 20 mg / mL conductive elastomer solution. Use a high-speed disperser to disperse and mix for 0.5-2 hours at a speed of 5000-10000rpm / min. After being fully mixed, set aside for later use.

[0071] S303: Fix the base material on a flat heating table, heat it to 60-120℃, and use an ultrasonic sprayer (Oriental Jinrong, UC360c) to ultrasonically spray the solution. Add the conductive elastomer solution into the sprayer and spray it at a rate of 0.07-0.12mL / cm2 according to the base film area. 2 Spray the conductive elastomer solution evenly on the base film. After spraying the conductive elastomer solution, spray the solvent in the solution on the surface at a spraying rate of 0.02-0.05mL / cm 2 , so that the elastic body is tightly connected. The amount of conductive elastomer solution used is 0.089mL / cm 2 Continue heating for 5-10 minutes, and then remove the conductive elastomer film after the solvent has completely evaporated.

[0072] S304: Cut the prepared conductive elastomer film into a specific shape to match the electrode layer. Encapsulate the conductive layer and electrode layer using liquid glue. Apply the liquid glue evenly around the electrode layer. Then, completely cover the cut conductive layer with the electrode layer and wait for 30-60 minutes for the glue to fully cure, resulting in a flexible pressure sensor with a spatially porous surface structure.

[0073] The present invention mixes a high-boiling point solution and a low-boiling point solution in a preset ratio to dissolve the elastomer, thereby realizing a spatial pore structure capable of sensing slight force deformation. The low-boiling point solvent evaporates rapidly during the spraying process of the elastomer solution, causing the elastomer solute to solidify rapidly, and gradually accumulates into a spatial pore structure in the form of fine droplets during the spraying process. The high-boiling point solvent is deposited in the lower layer, and the elastomer solute slowly solidifies to achieve a close bond with the substrate material. Using ultrasonic spraying instead of traditional carrier gas spraying is more advantageous for constructing a spatial void structure, and can spray out finer droplets to form finer pore walls. At the same time, under extremely small force conditions, the spatial pore structure constructed by the elastomer can undergo large deformation, resulting in more overlapping conductive paths, resulting in obvious electrical signal changes, and the force conditions can be detected. The flexible sensor provided by the present invention can sense slight forces and provide obvious feedback on Pa-level forces.

[0074] Comparative Example 1

[0075] This comparative example provides a flexible pressure sensor. The only difference between this comparative example and Example 1 is that the conductive elastomer is obtained by dissolving the elastomer in toluene and then adding a conductive filler.

[0076] In this comparative example, please refer to Figure 4, which shows a scanning electron microscope image of a flexible pressure sensor provided in this comparative example. It can be seen that if the elastomer is dissolved in toluene alone, without using high- and low-boiling-point solutions to achieve a stepwise volatilization, it is impossible to form a spatial pore structure capable of deforming to detect slight forces. Please refer to Figure 5, which shows the 1 / R ratio versus time curve of the sensor under 3 Pa pressure loading and unloading in this comparative example. As can be seen from the figure, the flexible pressure sensor provided in this comparative example cannot detect a pressure of 3 Pa.

[0077] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A flexible pressure sensor, characterized in that: From top to bottom, it includes a base layer, a conductive pressure-sensitive layer, a packaging layer and an electrode layer; the conductive pressure-sensitive layer is based on the base layer and is composed of a conductive elastomer with a spatial pore structure; wherein the shape of the spatial pore structure is circular or irregular; the size of the spatial pore structure ranges from 100 microns to 500 microns; the conductive elastomer is obtained by mixing a high-boiling point solution and a low-boiling point solution in a preset proportion to dissolve the elastomer, and then adding a conductive filler; the packaging layer combines the conductive pressure-sensitive layer and the electrode layer.

2. The flexible pressure sensor according to claim 1, characterized in that: The base layer is one of a PC film, a PVC film, a PET film, a PP film, a PS film, a PI film, a PMMA film, and a PEEK film.

3. The flexible pressure sensor according to claim 1, characterized in that: One or both sides of the base layer are frosted.

4. The flexible pressure sensor according to claim 1, characterized in that: The low boiling point solution is one or more of tetrahydrofuran, acetone, butanone, dichloroethane, and isopropanol, and the high boiling point solution is one or more of N,N-dimethylformamide, toluene, chlorobenzene, xylene, and cyclohexanone.

5. The flexible pressure sensor according to claim 1, characterized in that: The elastomer is one or more of TPU, TPE, SBS, SEBS and SEPS.

6. The flexible pressure sensor according to claim 1, characterized in that: The conductive filler is one or more of carbon nanotubes, carbon black, graphite, and graphene; the mass of the conductive filler is 0.2-40 mg / mL.

7. The flexible pressure sensor according to claim 1, characterized in that: The volume ratio of the high boiling point solution to the low boiling point solution is 1:1-1:

10.

8. The flexible pressure sensor according to claim 1, characterized in that: The high boiling point solution and the low boiling point solution are mixed in a preset ratio to dissolve the elastomer to obtain a solution concentration of 0.2-100 mg / mL.

9. The flexible pressure sensor according to claim 1, characterized in that: The encapsulation layer is liquid glue.

10. The flexible pressure sensor according to claim 1, characterized in that: The electrode layer is a flexible FPC or a conductive path made by screen printing.

11. A method for preparing a flexible pressure sensor according to any one of claims 1 to 10, characterized in that: include: Obtaining a base layer of a preset size, and cleaning the surface of the base layer using a plasma cleaning machine; The high boiling point solution and the low boiling point solution are mixed according to a preset ratio to dissolve the elastomer, and a conductive filler is added to obtain a conductive elastomer solution; Heating the base layer, and uniformly spraying the conductive elastomer solution on the base layer by ultrasonic spraying to obtain a conductive pressure-sensitive layer; The conductive pressure-sensitive layer and the electrode layer are packaged by liquid glue to obtain a flexible pressure sensor.

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