Flexible resistance type bending sensor

Abstract

The invention provides a flexible resistance type bending sensor, which comprises a flexible insulating substrate layer, a flexible sensitive electrode layer and an electrode lead, and is characterized in that the resistance of the flexible sensitive electrode layer is measured through the electrode lead; the flexible sensitive electrode layer comprises a flexible polymer material and conductive particles, and the conductive particles are uniformly dispersed in the flexible polymer material; the flexible sensitive electrode layer further comprises large particles, or / and a plurality of protrusions are formed on the surface of the flexible sensitive electrode layer, pits are formed between the adjacent protrusions, and the particle size of the large particles is larger than that of the conductive particles. The flexible resistance-type bending sensor is simple in structure and has high sensitivity and high cycling stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible electronics and sensors, and in particular relates to a flexible resistive bending sensor. Background Art

[0002] With the continuous development of human society's intelligence, electronic sensing technology has been paid more and more attention. Flexible, bendable and stretchable flexible sensing technology is the key technology of flexible intelligence, and has urgent application needs in the fields of wearable electronics, medical treatment, robotics, etc.

[0003] A flexible bending sensor is a flexible device that identifies external bending deformation (including bending direction and full angle) information and converts it into electrical signals. According to different working principles, flexible bending sensors can be divided into photoelectric, piezoresistive, capacitive and other flexible sensors. Flexible photoelectric bending sensors generally use optical fiber signal changes to collect and monitor bending signals, but require complex supporting equipment. Flexible capacitive bending sensors mainly recognize the degree of bending through changes in capacitance between the sensitive film and the parallel electrode layer. Similarly, flexible resistive bending sensors recognize the degree of bending by measuring changes in the resistance of the electrode.

[0004] Sensitivity and stability are two important properties of flexible bending sensors. When the sensitivity is high, the flexible bending sensor can obtain a larger numerical feedback when subjected to a smaller bending strain. When the stability is high, the flexible bending sensor returns to its original shape after bending deformation, and its numerical feedback is basically restored. With the continuous development of flexible sensing technology, the requirements for the sensitivity and stability of flexible bending sensors are gradually increasing. Obtaining a flexible bending sensor with high sensitivity and high stability is one of the key research topics for technicians in this field. Summary of the invention

[0005] In view of the above technical status, the present invention aims to improve a flexible resistive bending sensor, which has a simple structure, is easy to implement, and has high sensitivity and high cycle stability.

[0006] A technical solution provided by the present invention is: a flexible resistive bending sensor, such as Figure 1-3 As shown, it includes a flexible insulating base layer, a flexible sensitive electrode layer and an electrode lead; the flexible sensitive electrode layer is located on the surface of the flexible insulating base layer, the electrode lead is connected to the flexible sensitive electrode layer, and the resistance of the flexible sensitive electrode layer is measured through the electrode lead;

[0007] The flexible sensitive electrode layer is flexible and conductive as a whole, and comprises a flexible polymer material and conductive particles, wherein the conductive particles are uniformly dispersed in the flexible polymer material;

[0008] like Figure 1-3As shown, the flexible sensitive electrode layer includes large particles, and / or a plurality of protrusions are formed on the surface of the flexible sensitive electrode layer, and pits are formed between adjacent protrusions.

[0009] The particle size of the large particles is larger than that of the conductive particles.

[0010] The conductive particles are not limited, and include metal particles, carbon particles, etc. The carbon particles include graphite particles, graphene particles, carbon nanotube particles, etc.

[0011] The flexible polymer material is not limited and includes polyvinyl acetate, etc. Preferably, the flexible polymer material also includes one or more additives such as polyethanol, polyvinyl butyral, carboxylic acid-modified polyvinyl acetal, etc.

[0012] The constituent material of the flexible insulating base layer is not limited, including one or more of Pi, PET, PDMS, PU, ​​PC, PMMA and the like.

[0013] The shape of the protrusion is not limited, and can be a regular shape, such as a rectangle, a cone, an arc, etc., or an irregular shape.

[0014] The arrangement of the protrusions is not limited, and may form a regular array arrangement, such as a matrix arrangement, a linear arrangement, etc., or may form an irregular arrangement.

[0015] Preferably, the particle size of the large particles is in the range of 1 μm-500 μm, and more preferably in the range of 10 μm-200 μm.

[0016] Preferably, the conductive particles have a particle size of 0.01 μm-10 μm.

[0017] The large particles may be conductive particles, such as graphite particles, carbon microsphere particles, etc., or non-conductive particles, such as glass powder, hollow glass beads, PMMA microsphere particles, etc.

[0018] As a way to achieve this, Figure 4 , 6 As shown, the electrode lead has a layered structure, which is recorded as an electrode lead layer. The electrode lead layer is located on the surface of the flexible insulating base layer, and the flexible sensitive electrode layer is located on the surface of the electrode lead layer.

[0019] In order to take into account both the high sensitivity and high tensile strength of the bending sensor, Figure 5 , 6 As shown, the bending sensor further includes a flexible insulating reinforcement layer, the flexible insulating base layer is located on the surface of the flexible insulating reinforcement layer, and the elastic modulus of the flexible insulating base layer is smaller than the elastic modulus of the flexible insulating reinforcement layer.

[0020] The elastic modulus, also known as Young's modulus, is one of the most important and characteristic mechanical properties of elastic materials. It is a representation of the ease of elastic deformation of an object. It is defined as the stress required for a material to produce unit elastic deformation under the action of an external force, and its unit is Pa.

[0021] Preferably, a silver zebra electrode is arranged on the surface of the flexible sensitive electrode layer, and the silver zebra electrode refers to a plurality of strip-shaped silver electrodes arranged linearly, and there is a spacing between adjacent electrodes. Preferably, the width of the strip silver electrode is 50μm-500μm, and the spacing between adjacent silver electrodes is preferably 50μm-500μm. Since the silver resistance is low, the surface resistance can be significantly reduced. When the sensor is bent and deformed toward the side of the flexible insulating base layer, microcracks are also generated on the surface of the silver resistor, thereby significantly increasing the resistance value. Conversely, when the sensor is bent and deformed toward the side of the flexible sensitive electrode layer, the surface of the silver resistor is also stacked and closely contacted, thereby significantly reducing the resistance value. Therefore, the silver electrode can further increase the resistance change rate when the sensor is bent.

[0022] The method for preparing the flexible sensitive electrode layer comprises the following steps:

[0023] (1) mixing polymer materials, conductive particles, and organic solvents uniformly to form a slurry; when the flexible sensitive electrode layer includes large particles, mixing polymer materials, large particles, conductive particles, and organic solvents uniformly to form a slurry;

[0024] (2) coating, screen printing or casting the slurry on the surface of the flexible insulating base layer to form a flexible sensitive electrode layer; when the surface of the flexible sensitive electrode layer has the protrusions, performing morphology control on the surface of the flexible sensitive electrode layer to form the protrusions and pits.

[0025] In the step (2), the method for morphology control is not limited, such as a mold method, a laser etching method, etc.

[0026] For example, after screen printing the slurry, it is heat treated at a temperature of 60° C.-120° C. for a time of 1 min-10 min; then, a tooling mold is used to roll the surface to form the undulating shape.

[0027] For example, after screen printing the slurry, it is heat treated at a temperature of 150°C-180°C for 10min-30min; then, laser etching is performed on the surface to form the undulating shape, and the etching depth is adjusted by adjusting the laser power and etching rate.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) In the present invention, the sensor has a layered structure. As an implementation method, a plurality of protrusions and pits are formed on the surface of the flexible sensitive electrode layer, so that the surface of the flexible sensitive electrode layer is undulating. Compared with a flexible sensitive electrode layer having a flat surface, it has the following advantages:

[0030] When the sensor bends toward the side of the flexible insulating base layer and the surface of the flexible sensitive electrode layer is stretched, due to the spacing between adjacent protrusions, microcracks are likely to appear at the connection position between the protrusions and the depressions during stretching, and the surface is easily stretched. The resistance change rate of the flexible sensitive electrode layer caused by stretching increases, thereby increasing the sensitivity of the bending sensor;

[0031] When the sensor bends toward the side of the flexible sensitive electrode layer and the surface of the flexible sensitive electrode layer is compressed and stacked, the surface is easily compressed due to the spacing between adjacent protrusions, and the resistance change rate caused by compression increases, thereby increasing the sensitivity of the bending sensor;

[0032] When the sensor recovers from bending deformation, it is easy to return to the initial state, thereby improving the stability of the sensor.

[0033] (2) In the present invention, as an implementation mode, the flexible sensitive electrode layer of the sensor includes large particles, which has the following advantages compared with the flexible sensitive electrode layer not including large particles:

[0034] When the sensor bends toward the side of the flexible insulating substrate layer and the surface of the flexible sensitive electrode layer is stretched, the presence of large particles easily generates microcracks, which increases the distance between the conductive particles and the resistance change rate, thereby improving the sensitivity of the bending sensor; considering that when large particles have low hardness, their deformation ability is high when stretched, which is not conducive to promoting the generation of microcracks, it is appropriate to select large particles with higher hardness;

[0035] When the sensor bends toward the flexible sensitive electrode layer and the surface of the flexible sensitive electrode layer is compressed and stacked, the distance between the large particles decreases due to the presence of large particles, so the resistance change rate increases, thereby increasing the sensitivity of the bending sensor.

[0036] (3) The present invention preferably forms a plurality of protrusions and depressions on the surface of the flexible sensitive electrode layer, and simultaneously arranges large particles in the flexible sensitive electrode layer, which can further improve the sensitivity of the sensor.

[0037] (4) The present invention preferably arranges a zebra silver electrode on the surface of the flexible sensitive electrode layer, which can further improve the sensitivity of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a structural schematic diagram of the resistive bending sensor of the present invention.

[0039] Figure 2 It is a structural schematic diagram of the resistive bending sensor of the present invention.

[0040] Figure 3 It is a structural schematic diagram of the resistive bending sensor of the present invention.

[0041] Figure 4 It is a structural schematic diagram of the resistive bending sensor of the present invention.

[0042] Figure 5 It is a structural schematic diagram of the resistive bending sensor of the present invention.

[0043] Figure 6 It is a structural schematic diagram of the resistive bending sensor of the present invention.

[0044] Figure 7 yes Figure 6 Top view of the .

[0045] Figure 8 yes Figure 6 A top view of a resistive bending sensor with silver zebra electrodes disposed on the surface of the flexible sensitive electrode layer.

[0046] Fig. 9 It is a schematic diagram of the sensor in comparative example 1 of the present invention when it is bent toward the side of the flexible insulating base layer.

[0047] Fig.10 It is a schematic diagram of the sensor in Example 1 of the present invention when it is bent toward the side of the flexible insulating base layer.

[0048] Fig.11 It is a schematic diagram of the sensor in Example 2-4 of the present invention when it is bent toward the side of the flexible insulating base layer.

[0049] Figure 1-9 The figure marks in the figure are: flexible insulating base layer 10, flexible sensitive electrode layer 20, conductive particles 21, large particles 22, protrusions 23, pits 24, zebra electrodes 25, microcracks 26, electrode leads 30, electrode lead layer 31, and flexible insulating reinforcement layer 40.

[0050] Figure 1-11 This is a structural diagram, and the dimensions are not the actual dimensions of the actual structure. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with the embodiments and drawings. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0052] Embodiment 1:

[0053] like Figure 6 As shown, the flexible resistive bending sensor has a stacked structure, which includes a flexible insulating reinforcement layer 40 , a flexible insulating base layer 10 , an electrode lead layer 31 , and a flexible sensitive electrode layer 20 from bottom to top.

[0054] The flexible insulating reinforcement layer 40 is a flexible PET substrate with an elastic modulus of 3 GPa-5 GPa.

[0055] The flexible insulating substrate 10 is a Pi film, and its elastic modulus is 1 GPa-3 GPa and its thickness is 0.05 μm-0.25 μm.

[0056] The electrode lead layer 31 is a silver film with a thickness of 10 μm-50 μm.

[0057] The flexible sensitive electrode layer 20 is formed by screen printing of slurry, the mass of the slurry is 100 parts, and the components and their contents in the slurry are:

[0058] 0.4 parts of polyethanol, 10-20 parts of conductive carbon black with a particle size of 0.01μm-10μm, 3-8 parts of micro wax powder, and the rest of the parts are polyvinyl acetate.

[0059] A number of square protrusions with a diameter of 30 μm-300 μm and a height of 10 μm-60 μm are formed on the surface of the flexible sensitive electrode layer, and pits with a width of 15 μm and a depth of 10 μm-60 μm are formed between adjacent protrusions. These protrusions form a regular matrix arrangement.

[0060] The preparation method of the flexible resistive bending sensor is as follows:

[0061] (1) Screen-printing silver paste on the surface of the flexible insulating substrate 10 to obtain the electrode lead layer 31, baking it in an oven at 90° C. to 200° C. for 1 min to 30 min, and then taking it out to dry.

[0062] (2-1) 80 g of polyethanol is added to polyvinyl acetate at a mass fraction of 0.4%, and then the conductive carbon black and micro wax powder are added and dispersed evenly by ultrasonic dispersion. The evenly dispersed slurry is placed in a star ball mill, zircon is added, and ball milled for 24 hours, and then taken out and placed in a three-roll mill for further even dispersion to obtain a sensitive layer slurry with evenly distributed particles. The sensitive layer slurry is screen-printed on the surface of the electrode lead layer 31 using a screen with a mesh size of 150 by a screen printing process to obtain a flexible sensitive electrode layer with a smooth surface.

[0063] (2-2) The flexible sensitive electrode layer obtained after the treatment in step (2-1) is preheated at 100°C for 10 minutes. After the preheating treatment, it is subjected to high temperature treatment, placed in a high temperature box, and heat treated at 180°C for 15 minutes. Then, it is placed on a laser processing platform, the power is adjusted to 5%-50%, the moving speed is 10 mm / m-300 mm / m, the processing times are 1-4 times, and micro-engraving is performed with reference to the set surface rectangular pattern to form a cube structure on the surface of the sensitive layer, with a diameter of 30μm-300μm and a height of 10μm-60μm, and there are grooves with a width of 15μm and a depth of 10μm-60μm between the cube structures.

[0064] (3) The flexible insulating substrate 10 obtained in step (2-2) is adhered to a flexible PET substrate, wherein the thickness of the adhesive is 0.01 μm.

[0065] Comparative Example 1:

[0066] In this embodiment, the structure of the flexible resistive bending sensor is substantially the same as that of the flexible resistive bending sensor in Embodiment 1, except that in this embodiment, the surface of the flexible sensitive electrode layer is flat without the protrusions in Embodiment 1.

[0067] In this embodiment, the preparation method of the flexible resistive bending sensor is basically the same as the preparation method of the flexible resistive bending sensor in Example 1, except that: after step (2-1), step (2-2) is not performed, but the flexible insulating substrate 10 obtained in step (2-1) is directly adhered to the flexible PET substrate, wherein the thickness of the adhesive is 0.01 μm.

[0068] Embodiment 2:

[0069] In this embodiment, the structure of the flexible resistive bending sensor is basically the same as that of the flexible resistive bending sensor in Comparative Example 1, except that the slurry of the flexible sensitive electrode layer 4 also includes 5-10 portions of large particles with a particle size of 50 μm, and the large particles are carbon black.

[0070] In this embodiment, the preparation method of the flexible resistive bending sensor is basically the same as the preparation method of the flexible resistive bending sensor in Comparative Example 1, except that in step (2-1), 5-10 parts of carbon black with a particle size of 50 μm are also added to the solvent.

[0071] Embodiment 3:

[0072] In this embodiment, the structure of the flexible resistive bending sensor is substantially the same as that of the flexible resistive bending sensor in Embodiment 2, except that the large particles are glass beads having an average particle size of 100 μm.

[0073] In this embodiment, the preparation method of the flexible resistive bending sensor is basically the same as the preparation method of the flexible resistive bending sensor in Example 2, except that in step (2-1), 5-10 parts of glass beads with a particle size of 100 μm are also added to the solvent.

[0074] Embodiment 4:

[0075] In this embodiment, the structure of the flexible resistive bending sensor is substantially the same as that of the flexible resistive bending sensor in Embodiment 2, except that the large particles are PMMA balls with an average particle size of 50 μm.

[0076] In this embodiment, the preparation method of the flexible resistive bending sensor is basically the same as the preparation method of the flexible resistive bending sensor in Example 2, except that in step (2-1), 5-10 parts of PMMA balls with a particle size of 50 μm are also added to the solvent.

[0077] Embodiment 5:

[0078] In this embodiment, the structure of the flexible resistive bending sensor is basically the same as that of the flexible resistive bending sensor in Embodiment 1. The difference is that the surface of the flexible sensitive electrode layer is further provided with Figure 8 The silver zebra electrodes shown are strip-shaped silver electrodes with a width of 50 μm-500 μm, and a spacing between adjacent silver electrodes of 50 μm-500 μm.

[0079] In this embodiment, the preparation method of the flexible resistive bending sensor is basically the same as the preparation method of the flexible resistive bending sensor in Example 1, except that: the flexible sensitive electrode layer obtained in step (2-2) is placed on a screen printing platform, and the zebra electrode is screen printed, the screen printing screen mesh is 150 mesh, and the screen printing thickness is 10μm-50μm. The zebra electrode is baked in an oven at 90℃-200℃ for 1min-30min to obtain the zebra electrode, and then step (3) is performed.

[0080] Embodiment 6:

[0081] In this embodiment, the structure of the flexible resistive bending sensor is basically the same as that of the flexible resistive bending sensor in Embodiment 2. The difference is that the surface of the flexible sensitive electrode layer is further provided with Figure 8 The silver zebra electrodes shown are strip-shaped silver electrodes with a width of 50 μm-500 μm, and a spacing between adjacent silver electrodes of 50 μm-500 μm.

[0082] In this embodiment, the preparation method of the flexible resistive bending sensor is basically the same as the preparation method of the flexible resistive bending sensor in Example 2, except that: the flexible sensitive electrode layer obtained in step (2-1) is placed on a screen printing platform, and the zebra electrode is screen printed, the screen printing screen mesh is 150 mesh, and the screen printing thickness is 10μm-50μm. The zebra electrode is baked in an oven at 90℃-200℃ for 1min-30min to obtain the zebra electrode, and then step (3) is performed.

[0083] The sensors in Examples 1-6 and Comparative Example 1 were subjected to a bending test, and the bending method was as follows:

[0084] Wires are welded at both ends of the electrode lead layer 31 and connected to a resistance tester. One end of the flexible resistance bending sensor is fixed and the other end is suspended. External force is applied to the suspended end to make the sensor bend toward the side of the flexible insulating base layer. The surface of the flexible sensitive electrode layer is gradually stretched and then gradually restored to its original state. The resistance at both ends of the electrode lead layer during the deformation process is tested.

[0085] In Comparative Example 1, when the sensor is bent toward the flexible insulating substrate layer, the surface of the flexible sensitive electrode layer is stretched and microcracks appear, such as Fig. 9 shown.

[0086] In Example 1, when the sensor is bent toward the flexible insulating base layer, the surface of the flexible sensitive electrode layer is stretched. Fig.10 As shown in the figure, due to the existence of convex and concave structures, micro cracks are prone to appear at the connection position between the convex and concave. Fig. 9 Compared with the bending sensor, the number of microcracks increases, the surface is easy to stretch, and the resistance change rate of the flexible sensitive electrode layer caused by stretching increases, thereby increasing the sensitivity of the bending sensor. When the sensor recovers from bending deformation, it is easy to return to the initial state, thereby improving the stability of the sensor.

[0087] In Example 2-4, when the sensor is bent toward the flexible insulating base layer, the surface of the flexible sensitive electrode layer is stretched. Fig.11 As shown in the figure, due to the presence of large particles, micro cracks are likely to appear at the location of the large particles during bending deformation. Fig. 9 Compared with the bending sensor, the number of microcracks increases. Due to the presence of these microcracks, the distance between the conductive particles increases, the resistance change rate increases, and thus the sensitivity of the bending sensor is improved. When the sensor recovers from bending deformation, it is easy to return to the initial state, thereby improving the stability of the sensor.

[0088] The test results are shown in Table 1.

[0089] Table 1: Resistance changes of the sensors in Examples 1-5 and Comparative Example 1 after bending and deformation toward the flexible insulating substrate layer

[0090]

[0091] From Table 1 we can see that:

[0092] (1) Compared with Comparative Example 1, in Example 1, due to the provision of the protrusion and depression structure, the resistance value change rate increases after the sensor is bent from the initial position to the side of the flexible insulating base layer;

[0093] (2) Compared with Comparative Example 1, in Examples 2-4, since the flexible sensitive electrode layer is provided with large particles, the resistance value change rate increases after the sensor is bent from the initial position to the side of the flexible insulating base layer;

[0094] (3) Compared with Example 1, since a silver zebra electrode is further provided in Example 5, the rate of change of the resistance value increases after the sensor is bent from the initial position to the side of the flexible insulating base layer; compared with Example 2, since a silver zebra electrode is further provided in Example 6, the rate of change of the resistance value increases after the sensor is bent from the initial position to the side of the flexible insulating base layer.

[0095] The sensors in Examples 1-6 and Comparative Example 1 were subjected to a bending test, and the bending method was as follows:

[0096] Wires are welded at both ends of the electrode lead layer 31 and connected to a resistance tester. One end of the flexible resistance bending sensor is fixed and the other end is suspended. External force is applied to the suspended end to make the sensor bend toward the flexible sensitive electrode layer. The surface of the flexible sensitive electrode layer is gradually compressed and piled up to make close contact, and then gradually returns to its original state. The resistance at both ends of the electrode lead layer during the deformation process is tested.

[0097] In Comparative Example 1, when the sensor bends and deforms toward the flexible sensitive electrode layer, the surface of the flexible sensitive electrode layer is gradually compressed and stacked to be in close contact, and the resistance gradually decreases.

[0098] In Example 1, when the sensor bends toward the side of the flexible sensitive electrode layer, the surface of the flexible sensitive electrode layer is gradually compressed and stacked to form a close contact. At the same time, due to the presence of depressions between the protrusions, the surface is easily compressed and stacked. Therefore, compared with Comparative Example 1, the resistance change rate increases, thereby increasing the sensitivity of the bending sensor.

[0099] In Examples 2-4, when the sensor bends toward the side of the flexible sensitive electrode layer, the surface of the flexible sensitive electrode layer is gradually compressed and stacked into close contact. At the same time, due to the presence of large particles, the distance between the large particles is also reduced during compression and stacking. Therefore, compared with Comparative Example 1, the resistance change rate increases, thereby increasing the sensitivity of the bending sensor.

[0100] The test results are shown in Table 2.

[0101] Table 2: Resistance changes of the sensors in Examples 1-6 and Comparative Example 1 after bending and deforming toward the flexible sensitive electrode layer

[0102]

[0103]

[0104] From Table 2 we can see that:

[0105] (1) Compared with Comparative Example 1, in Example 1, due to the provision of the protrusion and depression structure, the resistance value change rate increases after the sensor is bent from the initial position to the side of the flexible sensitive electrode layer;

[0106] (2) Compared with Comparative Example 1, in Examples 2-4, since the flexible sensitive electrode layer is provided with large particles, the resistance value change rate increases after the sensor is bent and deformed from the initial position to one side of the flexible sensitive electrode layer;

[0107] (3) Compared with Example 1, in Example 5, since a silver zebra electrode is also provided, the rate of change of the resistance value increases after the sensor is bent from the initial position to the side of the flexible sensitive electrode layer; compared with Example 2, in Example 6, since a silver zebra electrode is also provided, the rate of change of the resistance value increases after the sensor is bent from the initial position to the side of the flexible sensitive electrode layer.

[0108] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A flexible resistive bending sensor, characterized in that: It includes a flexible insulating base layer, a flexible sensitive electrode layer and an electrode lead; the flexible sensitive electrode layer is located on the surface of the flexible insulating base layer, the electrode lead is connected to the flexible sensitive electrode layer, and the resistance of the flexible sensitive electrode layer is measured through the electrode lead; The flexible sensitive electrode layer is flexible and conductive, and comprises a flexible polymer material and conductive particles, wherein the conductive particles are uniformly dispersed in the flexible polymer material; The flexible sensitive electrode layer further includes large particles, or / and a plurality of protrusions are formed on the surface of the flexible sensitive electrode layer, and pits are formed between adjacent protrusions; The particle size of the large particles is larger than that of the conductive particles.

2. The flexible resistive bending sensor according to claim 1, characterized in that: The conductive particles include one or both of metal particles and carbon particles; Preferably, the carbon particles include one or more of graphite particles, graphene particles, and carbon nanotube particles; Preferably, the conductive particles have a particle size of 0.01 μm-10 μm.

3. The flexible resistive bending sensor according to claim 1, characterized in that: The flexible polymer material includes polyvinyl acetate; Preferably, the flexible polymer material further comprises one or more of polyethanol, polyvinyl butyral, and carboxylic acid-modified polyvinyl acetal.

4. The flexible resistive bending sensor according to claim 1, wherein: The protrusions are arranged in a regular array.

5. The flexible resistive bending sensor according to claim 1, characterized in that: The particle size of the large particles is 1 μm-500 μm, preferably in the range of 10 μm-200 μm; Preferably, the large particles are one or more of graphite particles, carbon microsphere particles, glass powder, hollow glass beads, and PMMA microsphere particles; Preferably, the large particles are hard large particles.

6. The flexible resistive bending sensor according to claim 1, characterized in that: The electrode lead has a layered structure, which is referred to as an electrode lead layer. The electrode lead layer is located on the surface of the flexible insulating base layer, and the flexible sensitive electrode layer is located on the surface of the electrode lead layer.

7. The flexible resistive bending sensor according to claim 1, characterized in that: The bending sensor further comprises a flexible insulating reinforcement layer, the flexible insulating base layer is located on the surface of the flexible insulating reinforcement layer, and the elastic modulus of the flexible insulating base layer is smaller than the elastic modulus of the flexible insulating reinforcement layer.

8. The flexible resistive bending sensor according to claim 1, characterized in that: Zebra electrodes are arranged on the surface of the flexible sensitive electrode layer.

9. The flexible resistive bending sensor according to any one of claims 1 to 8, characterized in that: The method for preparing the flexible sensitive electrode layer comprises the following steps: (1) mixing polymer materials, conductive particles, and organic solvents uniformly to form a slurry; when the flexible sensitive electrode layer includes large particles, mixing polymer materials, large particles, conductive particles, and organic solvents uniformly to form a slurry; (2) coating, screen printing or casting the slurry on the surface of the flexible insulating base layer to form a flexible sensitive electrode layer; When the surface of the flexible sensitive electrode layer has the protrusions, the morphology of the surface of the flexible sensitive electrode layer is regulated to form the protrusions and pits.

10. The flexible resistive bending sensor according to claim 9, characterized in that: In the step (2), the morphology control method includes a mold method and a laser etching method.

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