Flexible capacitive pressure sensor and preparation method thereof

Abstract

The invention discloses a flexible capacitive pressure sensor and a preparation method, and relates to the technical field of flexible capacitive pressure sensors.The flexible capacitive pressure sensor comprises a shell, a second binding post arranged at one end of the shell, a shell cover arranged at the other end of the shell and a first binding post arranged on the shell cover, an upper packaging layer is arranged in the shell, an upper electrode layer is arranged on one side of the upper packaging layer, and a lower electrode layer is arranged on the other side of the upper packaging layer; a middle dielectric layer is arranged on one side of the upper electrode layer, a lower electrode layer is arranged on one side of the middle dielectric layer, and a lower packaging layer is arranged on one side of the lower electrode layer; conductive film structures are arranged between the lower electrode layer and the middle dielectric layer and between the upper electrode layer and the middle dielectric layer; a sealing assembly is arranged in the shell cover; an extrusion assembly is further arranged in the shell cover; by using the sealing assembly, the sealing performance between the shell and the shell cover is improved, external moisture and dust are prevented from entering the shell, the accuracy of capacitance measurement is improved, and the service life of the flexible capacitive pressure sensor is further prolonged.

Description

Technical Field

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

[0002] A flexible capacitive pressure sensor is a sensor that detects pressure based on changes in capacitance. It is flexible and bendable and is widely used in wearable devices, medical monitoring, robotics and other fields. However, after long-term use, the seals of existing flexible capacitive pressure sensors will age or crack, resulting in poor sealing performance of the flexible capacitive pressure sensor, further causing external impurities such as moisture and dust to enter the sensor, affecting the accuracy of capacitance measurement and reducing the service life of the sensor. Summary of the Invention

[0003] In order to solve the problems in the background technology, the present invention proposes a flexible capacitive pressure sensor and a preparation method thereof.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A flexible capacitive pressure sensor, comprising a housing, a second terminal disposed at one end of the housing, a housing cover disposed at the other end of the housing, and a first terminal disposed on the housing cover; an upper packaging layer is disposed within the housing, an upper electrode layer is disposed on one side of the upper packaging layer, an intermediate dielectric layer is disposed on one side of the upper electrode layer, a lower electrode layer is disposed on one side of the intermediate dielectric layer, and a lower packaging layer is disposed on one side of the lower electrode layer;

[0006] A circular hole is formed in the first terminal post, a lead is provided in the circular hole, and the lead is fixedly connected to the lower electrode layer;

[0007] A third annular cavity is provided in the circular hole, and a fixing piece for fixing the lead is provided in the third annular cavity;

[0008] A conductive film structure is provided between the lower electrode layer, the upper electrode layer and the intermediate dielectric layer;

[0009] A sealing assembly for sealing the housing is provided in the housing cover;

[0010] An extrusion component is also provided in the shell cover.

[0011] Preferably, the sealing assembly includes an annular ring arranged on one side of the shell, an annular opening opened on a side of the shell cover and an annular cavity 2 opened in the annular opening, a sealing capsule is provided in the annular cavity 2, and the sealing capsule extends into the annular opening.

[0012] Preferably, a plurality of annular rubber rings are evenly arranged on the inner wall of the sealed capsule, and annular grooves are provided on the inner wall and outer wall of the annular ring to match the annular rubber rings.

[0013] Preferably, the sealed capsule is filled with hydraulic oil.

[0014] Preferably, the extrusion assembly includes multiple annular cavities 1 opened in the shell cover, cylindrical cavities symmetrically opened on the annular cavity 1, and circular grooves 1 and 2 respectively opened at the ends of the cylindrical cavity. A connecting rod is slidably provided in the cylindrical cavity, one end of the connecting rod is provided with a circular plate matching the circular groove 1, and the other end is provided with an extrusion plate matching the circular groove 2. A limiting plate is provided on the outer wall of the connecting rod in the annular cavity 1, and a reset spring is sleeved on the outer wall of the connecting rod between the limiting plate and the annular cavity 1.

[0015] Preferably, the conductive film structure includes a flexible substrate and sandpaper-molded microstructures disposed on both sides of the flexible substrate.

[0016] Preferably, the fixing part includes a sealing cavity symmetrically opened in the circular hole, a fixing plate fixed in the sealing cavity, a piston slidably arranged in the sealing cavity and a guide rod slidably arranged on the fixing plate, one end of the guide rod is fixed to the piston, and the other end is fixed to an arc-shaped movable plate, an arc-shaped plate is slidably provided on the inner wall of the arc-shaped movable plate, an extrusion spring is sleeved on the outer wall of the guide rod between the fixing plate and the piston, and the sealing cavity is connected to the sealing capsule through a conduit.

[0017] A method for preparing a flexible capacitive pressure sensor comprises the following steps:

[0018] S1: First, place the upper packaging layer, upper electrode layer, conductive film structure, middle dielectric layer, conductive film structure, lower electrode layer and lower packaging layer in the shell in order, then weld the lead wires to the lower electrode layer, and finally put the shell cover on the shell and connect the lead wires to the inside of the shell cover;

[0019] S2: After the shell cover is covered on the shell, the annular ring enters the sealing capsule and squeezes the sealing capsule, so that the sealing capsule wraps the annular ring, achieving the first seal between the shell and the shell cover;

[0020] When the sealed capsule is squeezed, the annular rubber ring enters the annular groove on the annular ring, thereby achieving a second seal between the shell and the shell cover; through the first and second sealing operations, the sealing between the shell and the shell cover is further improved;

[0021] S3: When the sealed capsule is squeezed again, the sealed capsule squeezes the circular plate, thereby driving the connecting rod to move, thereby driving the squeezing plate to move, thereby squeezing the lower packaging layer, the lower electrode layer, the conductive film structure, the intermediate dielectric layer, the upper electrode layer and the upper packaging layer, thereby preventing the lower packaging layer, the lower electrode layer, the conductive film structure, the intermediate dielectric layer, the upper electrode layer and the upper packaging layer from shaking in the shell when the flexible capacitive pressure sensor moves, thereby facilitating the use of the flexible capacitive pressure sensor;

[0022] S4: When the sealing capsule is squeezed, the hydraulic oil in the sealing capsule enters the sealing cavity through the conduit, thereby pushing the piston to move, thereby driving the guide rod to move, and further driving the arc movable plate and the arc plate to move, and finally, the two arc plates clamp and fix the lead.

[0023] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0024] 1. The present invention facilitates improving the sealing between the shell and the shell cover by using a sealing component, preventing external moisture and dust from entering the shell, improving the accuracy of capacitance measurement, and further improving the service life of the flexible capacitive pressure sensor; by using an extrusion component, it is convenient to squeeze the lower packaging layer, lower electrode layer, conductive film structure, intermediate dielectric layer, upper electrode layer and upper packaging layer in the shell, thereby preventing the lower packaging layer, lower electrode layer, conductive film structure, intermediate dielectric layer, upper electrode layer and upper packaging layer from shaking in the shell when the flexible capacitive pressure sensor is moved, thereby facilitating the use of the flexible capacitive pressure sensor;

[0025] 2. The present invention facilitates fixing the internal leads of the flexible capacitive pressure sensor through the use of fixing parts, preventing the leads from falling off during use, thereby ensuring the use of the flexible capacitive pressure sensor and improving the service life of the flexible capacitive pressure sensor; wherein the arc plate and the arc movable plate are set to slide with each other, so that after the arc plate contacts the lead, it will not drive the lead to rotate, avoiding the lead from falling off due to the rotation of the shell cover, thereby facilitating the protection of the lead, which is beneficial to the use of the flexible capacitive pressure sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It shows a schematic structural diagram of a front view provided by an embodiment of the present invention;

[0027] Figure 2 It shows a schematic diagram of a side view structure provided by an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of a cross-sectional structure according to a front view perspective provided by an embodiment of the present invention is shown;

[0029] Figure 4 An exploded view according to an embodiment of the present invention is shown;

[0030] Figure 5 for Figure 3 A partial enlarged view of point A in the middle;

[0031] Figure 6 for Figure 3 A partial enlarged view of the middle B;

[0032] Figure 7 A schematic structural diagram of a housing cover provided in an embodiment of the present invention is shown;

[0033] Figure 8 shows a schematic cross-sectional structure diagram of a housing cover provided according to an embodiment of the present invention;

[0034] Figure 9 A schematic structural diagram of a conductive film structure provided according to an embodiment of the present invention is shown;

[0035] Figure 10 A schematic structural diagram of a fixing member provided in an embodiment of the present invention is shown;

[0036] Figure 11 A schematic structural diagram of the connection between the arc-shaped plate and the arc-shaped movable plate provided in an embodiment of the present invention is shown.

[0037] Legend:

[0038] 1. Shell; 2. Shell cover; 3. Terminal 1; 4. Terminal 2; 5. Lower packaging layer; 6. Lower electrode layer; 7. Conductive film structure; 701. Flexible substrate; 702. Sandpaper microstructure; 8. Intermediate dielectric layer; 9. Upper electrode layer; 10. Upper packaging layer; 11. Sealing capsule; 12. Circular plate; 13. Limiting plate; 14. Annular cavity 1; 15. Return spring; 16. Extrusion plate; 17. Annular ring; 18. Annular rubber ring; 19. Annular shaped groove; 20, annular opening; 21, annular cavity 2; 22, circular groove 1; 23, cylindrical cavity; 24, circular groove 2; 25, hydraulic oil; 26, connecting rod; 27, conduit; 28, sealing cavity; 29, piston; 30, fixed plate; 31, arc plate; 32, guide rod; 33, extrusion spring; 34, arc-shaped movable plate; 35, annular cavity 3; 36, circular hole; 37, lead; 38, bending spring; 39, arc groove; 40, arc-shaped slider. DETAILED DESCRIPTION

[0039] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0040] Please refer to Figure 1 - Figure 11 The present application provides a technical solution:

[0041] The flexible capacitive pressure sensor comprises a shell 1, and the shell 1 is made of insulating plastic material to avoid the phenomenon of electric leakage, thereby facilitating the use of the flexible capacitive pressure sensor; a terminal post 4 is arranged at one end of the shell 1, a shell cover 2 is arranged at the other end of the shell 1, and a terminal post 1 is arranged on the shell cover 2, which are used for power supply of the flexible capacitive pressure sensor; an inner thread is formed on the inner wall of the shell 1, and an outer thread matched with the inner thread is formed on the outer wall of the end of the shell cover 2, thereby facilitating the connection between the shell 1 and the shell cover 2.

[0042] The shell 1 is internally provided with an upper packaging layer 10, one side of the upper packaging layer 10 is provided with an upper electrode layer 9, one side of the upper electrode layer 9 is provided with an intermediate dielectric layer 8, one side of the intermediate dielectric layer 8 is provided with a lower electrode layer 6, and one side of the lower electrode layer 6 is provided with a lower packaging layer 5; wherein the upper packaging layer 10 and the lower packaging layer 5 are both made of polydimethylsiloxane (PDMS) material, and since the polydimethylsiloxane (PDMS) material is a flexible material, the upper packaging layer 10 and the lower packaging layer 5 become soft, and the upper packaging layer 10 and the lower packaging layer 5 protect the internal lower electrode layer 6, intermediate dielectric layer 8 and upper electrode layer 9, prevent the external environment from interfering and damaging the flexible capacitive pressure sensor, and at the same time endow the sensor with good flexibility and waterproof performance; the upper electrode layer 9 and the lower electrode layer 6 are both made of conductive polymer material, and the conductive polymer is mixed with materials such as polyaniline, carbon nanotube and graphene which have good conductivity and flexibility; the intermediate dielectric layer 8 is made of flexible material with high dielectric constant, and can be made of polyvinylidene fluoride (PVDF) and copolymer material thereof and the like;

[0043] The terminal post 1 is internally provided with a circular hole 36, and the circular hole 36 is internally provided with a lead wire 37 which is fixedly connected with the lower electrode layer 6;

[0044] The circular hole 36 is internally provided with an annular cavity 35, and the annular cavity 35 is internally provided with a fixing piece for fixing the lead wire 37; through the use of the fixing piece, the lead wire 37 in the flexible capacitive pressure sensor can be fixed, so as to prevent the lead wire 37 from falling off during use, thereby ensuring the use of the flexible capacitive pressure sensor and improving the service life of the flexible capacitive pressure sensor;

[0045] The conductive film structure 7 is arranged between the lower electrode layer 6 and the upper electrode layer 9 and the intermediate dielectric layer 8; the conductive film structure 7 comprises a flexible substrate 701 and a sandpaper microstructure 702 arranged on both sides of the flexible substrate 701; the conductive film structure 7 with the sandpaper microstructure 702 is a conductive layer with a microstructure similar to the surface of the sandpaper formed on the flexible substrate 701; the microstructure can change the effective contact area between the intermediate dielectric layer 8, the upper electrode layer 9 and the lower electrode layer 6, and when subjected to pressure, the deformation of the sandpaper microstructure 702 can cause a significant change in the capacitance value, thereby enabling the flexible capacitive pressure sensor to have high sensitivity in a wide range.

[0046] The conductive film structure 7 is prepared by selecting 80-mesh sandpaper, placing the sandpaper in deionized water, and ultrasonic cleaning for 15 minutes to remove impurities and oil stains on the surface; then the sandpaper is placed in an oven and dried at 60℃ for 30 minutes; after the sandpaper is dried, a layer of silane release agent is evenly coated on the surface, and it is placed in a well-ventilated place to dry; then the conductive material such as polymer, carbon nanotube or graphene is dispersed in a suitable solvent to form a uniform conductive solution; the prepared conductive solution such as polyaniline, carbon nanotube or graphene is coated on the treated sandpaper by spin coating at a speed of 2000 rpm for 30 seconds; the sandpaper coated with the conductive solution is placed in an oven and dried at 80℃ for 2 hours to remove the solvent; after drying is completed, the conductive film structure 7 with the sandpaper microstructure 702 is carefully peeled off from the sandpaper;

[0047] The shell cover 2 is provided with a sealing assembly for sealing the shell 1; by using the sealing assembly, the sealing property between the shell 1 and the shell cover 2 can be improved, the moisture and dust from the outside can be prevented from entering the shell 1, the accuracy of capacitive measurement can be improved, and the service life of the flexible capacitive pressure sensor can be further improved;

[0048] The shell cover 2 is further provided with an extrusion assembly; by using the extrusion assembly, the extrusion between the lower packaging layer 5, the lower electrode layer 6, the conductive film structure 7, the intermediate dielectric layer 8, the upper electrode layer 9 and the upper packaging layer 10 in the shell 1 can be facilitated, and the lower packaging layer 5, the lower electrode layer 6, the conductive film structure 7, the intermediate dielectric layer 8, the upper electrode layer 9 and the upper packaging layer 10 in the shell 1 can be prevented from shaking when the flexible capacitive pressure sensor is moved, thereby facilitating the use of the flexible capacitive pressure sensor.

[0049] In the application, the sealing assembly comprises an annular ring 17 arranged on one side of the shell 1, an annular opening 20 arranged on one side surface of the shell cover 2, and an annular cavity two 21 arranged in the annular opening 20, wherein the sealing capsule 11 is arranged in the annular cavity two 21 and extends into the annular opening 20; the sealing capsule 11 is extruded by the annular ring 17 to wrap the outer wall of the annular ring 17, thereby realizing the first sealing between the shell cover 2 and the shell 1; wherein the sealing capsule 11 is made of rubber material, and the rubber has high elasticity, so that the sealing capsule 11 has high elasticity, thereby facilitating the deformation of the sealing capsule 11 and facilitating the sealing between the shell cover 2 and the shell 1.

[0050] In the application, the inner wall of the sealing capsule 11 is uniformly provided with a plurality of annular rubber rings 18, and the inner wall and the outer wall of the annular ring 17 are provided with annular grooves 19 matched with the annular rubber rings 18; the contact area between the sealing capsule 11 and the annular ring 17 is increased by the cooperation between the annular grooves 19 and the annular rubber rings 18, thereby improving the sealing performance between the shell cover 2 and the shell 1, i.e. realizing the second sealing between the shell cover 2 and the shell 1; the sealing performance between the shell cover 2 and the shell 1 is improved by the first sealing and the second sealing, thereby avoiding the dust or water vapor from the outside into the shell 1, and improving the service life of the flexible capacitive pressure sensor.

[0051] In the application, the sealing capsule 11 is filled with hydraulic oil 25; the sealing capsule 11 is filled by using the hydraulic oil 25, thereby ensuring that the sealing capsule 11 can drive the fixing member and the extrusion assembly to work after deformation.

[0052] In the present invention, the extrusion assembly includes a plurality of annular cavities 14 opened in the shell cover 2, a cylindrical cavity 23 symmetrically opened on the annular cavity 14, and a circular groove 1 22 and a circular groove 24 respectively opened at the ends of the cylindrical cavity 23. A connecting rod 26 is slidingly provided in the cylindrical cavity 23, and a circular plate 12 is provided at one end of the connecting rod 26 to cooperate with the circular groove 1 22. When the circular plate 12 is not squeezed, the circular plate 12 is located in the annular cavity 2 21 under the action of the reset spring 15; an extrusion plate 16 is provided at the other end to cooperate with the circular groove 24. A limit plate 13 is provided on the outer wall of the connecting rod 26 in the annular cavity 14 to limit A reset spring 15 is sleeved on the outer wall of the connecting rod 26 between the plate 13 and the annular cavity 14; the circular plate 12 is squeezed by the sealing capsule 11 to drive the connecting rod 26 to move, and then the squeezing plate 16 is driven to move, thereby realizing the squeezing between the lower packaging layer 5, the lower electrode layer 6, the conductive film structure 7, the intermediate dielectric layer 8, the upper electrode layer 9 and the upper packaging layer 10, thereby preventing the lower packaging layer 5, the lower electrode layer 6, the conductive film structure 7, the intermediate dielectric layer 8, the upper electrode layer 9 and the upper packaging layer 10 from shaking in the shell 1 when the flexible capacitive pressure sensor moves, which is beneficial to the use of the flexible capacitive pressure sensor.

[0053] In the present invention, the fixing member includes a sealed cavity 28 symmetrically opened in a circular hole 36, a fixed plate 30 fixed in the sealed cavity 28, a piston 29 slidably set in the sealed cavity 28, and a guide rod 32 slidably set on the fixed plate 30, one end of the guide rod 32 is fixed to the piston 29, and the other end is fixed to an arc-shaped movable plate 34, an arc-shaped groove 39 is opened on the inner wall of the arc-shaped movable plate 34, an arc-shaped slider 40 matching the arc-shaped groove 39 is provided on the outer wall of the arc plate 31, a bending spring 38 is provided between the arc-shaped slider 40 and the arc-shaped groove 39, and one end of the bending spring 38 is fixed to the arc-shaped slider 40. The other end is fixedly connected to the inner wall of the arc groove 39, which is used to position the arc plate 31, so as to facilitate clamping and fixing the lead 37; an extrusion spring 33 is sleeved on the outer wall of the guide rod 32 between the fixed plate 30 and the piston 29, and the sealing cavity 28 is connected to the sealing capsule 11 through the conduit 27; wherein, the arc plate 31 and the arc movable plate 34 are slidingly arranged with each other, so that after the arc plate 31 contacts the lead 37, it will not drive the lead 37 to rotate, thereby avoiding the lead 37 from falling off due to rotation, thereby facilitating the protection of the lead 37, which is beneficial to the use of the flexible capacitive pressure sensor.

[0054] Working principle: A method for preparing a flexible capacitive pressure sensor includes the following steps:

[0055] Step 1: First, place the upper packaging layer 10, the upper electrode layer 9, the conductive film structure 7, the intermediate dielectric layer 8, the conductive film structure 7, the lower electrode layer 6, and the lower packaging layer 5 in the housing 1 in order. Then, weld the lead 37 to the lower electrode layer 6. Finally, cover the shell 2 on the housing 1 and connect the lead 37 to the inside of the shell 2.

[0056] Step 2: After the shell cover 2 is threadedly connected to the shell 1, the annular ring 17 enters the sealing capsule 11 and squeezes the sealing capsule 11, so that the sealing capsule 11 wraps the annular ring 17, achieving the first seal between the shell 1 and the shell cover 2;

[0057] When the sealing capsule 11 is squeezed, the annular rubber ring 18 enters the annular groove 19 on the annular ring 17, thereby achieving a second seal between the shell 1 and the shell cover 2. Through the first and second sealing operations, the sealing between the shell 1 and the shell cover 2 is further improved.

[0058] Through the above-mentioned first and second sealing, the sealing between the housing 1 and the housing cover 2 is improved, and external dust or moisture is prevented from entering the housing 1, thereby increasing the service life of the flexible capacitive pressure sensor;

[0059] Step three: When the sealed capsule 11 is squeezed again, the sealed capsule 11 squeezes the circular plate 12, thereby driving the connecting rod 26 to move, thereby driving the squeezing plate 16 to move, thereby achieving squeezing between the lower packaging layer 5, the lower electrode layer 6, the conductive film structure 7, the intermediate dielectric layer 8, the upper electrode layer 9 and the upper packaging layer 10, thereby preventing the lower packaging layer 5, the lower electrode layer 6, the conductive film structure 7, the intermediate dielectric layer 8, the upper electrode layer 9 and the upper packaging layer 10 from shaking in the housing 1 when the flexible capacitive pressure sensor moves, thereby facilitating the use of the flexible capacitive pressure sensor;

[0060] Step 4: When the sealed capsule 11 is squeezed, the hydraulic oil 25 in the sealed capsule 11 will enter the sealed cavity 28 through the conduit 27, and then push the piston 29 to move, thereby driving the guide rod 32 to move, and further driving the arc movable plate 34 and the arc plate 31 to move synchronously, and finally, the two arc plates 31 clamp and fix the lead 37; wherein, when the two arc plates 31 are in contact with the lead 37, the arc plates 31 are in a stationary state, and will not drive the arc plates 31 to rotate with the rotation of the shell cover 2, so that the arc plates 31 will not slide with the lead 37, further avoiding friction between the arc plates 31 and the lead 37 to damage the lead 37 or the lead 37 to fall off due to rotation, thereby facilitating the protection of the lead 37 and facilitating the use of the flexible capacitive pressure sensor.

[0061] The above description of the embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flexible capacitive pressure sensor, comprising a housing (1), a second terminal (4) arranged at one end of the housing (1), a housing cover (2) arranged at the other end of the housing (1), and a first terminal (3) arranged on the housing cover (2), characterized in that: An upper packaging layer (10) is provided in the housing (1), an upper electrode layer (9) is provided on one side of the upper packaging layer (10), an intermediate dielectric layer (8) is provided on one side of the upper electrode layer (9), a lower electrode layer (6) is provided on one side of the intermediate dielectric layer (8), and a lower packaging layer (5) is provided on one side of the lower electrode layer (6); A circular hole (36) is provided in the first terminal (3), a lead wire (37) is provided in the circular hole (36), and the lead wire (37) is fixedly connected to the lower electrode layer (6); A third annular cavity (35) is provided in the circular hole (36), and a fixing member for fixing the lead wire (37) is provided in the third annular cavity (35); A conductive film structure (7) is provided between the lower electrode layer (6), the upper electrode layer (9) and the intermediate dielectric layer (8); A sealing assembly for sealing the housing (1) is provided in the housing cover (2); An extrusion component is also provided in the shell cover (2).

2. The flexible capacitive pressure sensor according to claim 1, characterized in that: The sealing assembly comprises an annular ring (17) arranged on one side of the shell (1), an annular opening (20) opened on one side of the shell cover (2), and an annular cavity (21) opened in the annular opening (20), wherein a sealing capsule (11) is arranged in the annular cavity (21), and the sealing capsule (11) extends into the annular opening (20).

3. The flexible capacitive pressure sensor according to claim 2, characterized in that: A plurality of annular rubber rings (18) are evenly arranged on the inner wall of the sealed capsule (11), and annular grooves (19) are provided on the inner and outer walls of the annular ring (17) to match the annular rubber rings (18).

4. The flexible capacitive pressure sensor according to claim 3, characterized in that: The sealing capsule (11) is filled with hydraulic oil (25).

5. The flexible capacitive pressure sensor according to claim 4, characterized in that: The extrusion assembly includes a plurality of annular cavities (14) provided in the shell cover (2), cylindrical cavities (23) symmetrically provided on the annular cavity (14), and circular grooves (22) and (24) provided at the ends of the cylindrical cavity (23), respectively. A connecting rod (26) is slidably provided in the cylindrical cavity (23), one end of the connecting rod (26) is provided with a circular plate (12) matching with the circular groove (22), and the other end is provided with an extrusion plate (16) matching with the circular groove (24), a limiting plate (13) is provided on the outer wall of the connecting rod (26) in the annular cavity (14), and a reset spring (15) is sleeved on the outer wall of the connecting rod (26) between the limiting plate (13) and the annular cavity (14).

6. The flexible capacitive pressure sensor according to claim 5, characterized in that: The conductive film structure (7) comprises a flexible substrate (701) and a sandpaper-molded microstructure (702) arranged on both sides of the flexible substrate (701).

7. The flexible capacitive pressure sensor according to claim 6, characterized in that: The fixing member includes a sealing cavity (28) symmetrically opened in a circular hole (36), a fixing plate (30) fixed in the sealing cavity (28), a piston (29) slidably arranged in the sealing cavity (28), and a guide rod (32) slidably arranged on the fixing plate (30), one end of the guide rod (32) is fixed to the piston (29), and the other end is fixed to an arc-shaped movable plate (34), an arc-shaped plate (31) is slidably provided on the inner wall of the arc-shaped movable plate (34), an extrusion spring (33) is sleeved on the outer wall of the guide rod (32) between the fixing plate (30) and the piston (29), and the sealing cavity (28) is connected to the sealing capsule (11) through a conduit (27).

8. A method for preparing a flexible capacitive pressure sensor, according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: first, the upper packaging layer (10), the upper electrode layer (9), the conductive film structure (7), the intermediate dielectric layer (8), the conductive film structure (7), the lower electrode layer (6) and the lower packaging layer (5) are sequentially placed in the housing (1), then, the lead (37) is welded to the lower electrode layer (6), and finally, the shell cover (2) is placed on the outer shell (1), and the lead (37) is connected to the inside of the shell cover (2); S2: After the shell cover (2) is placed on the shell (1), the annular ring (17) enters the sealing capsule (11) and squeezes the sealing capsule (11), so that the sealing capsule (11) wraps around the annular ring (17), thereby achieving the first seal between the shell (1) and the shell cover (2); When the sealing capsule (11) is squeezed, the annular rubber ring (18) enters the annular groove (19) on the annular ring (17), thereby achieving a second seal between the shell (1) and the shell cover (2); through the first and second sealing operations, the sealing performance between the shell (1) and the shell cover (2) is further improved; S3: When the sealing capsule (11) is squeezed again, the sealing capsule (11) squeezes the circular plate (12), thereby driving the connecting rod (26) to move, thereby driving the squeezing plate (16) to move, thereby achieving squeezing between the lower packaging layer (5), the lower electrode layer (6), the conductive film structure (7), the intermediate dielectric layer (8), the upper electrode layer (9) and the upper packaging layer (10), thereby preventing the lower packaging layer (5), the lower electrode layer (6), the conductive film structure (7), the intermediate dielectric layer (8), the upper electrode layer (9) and the upper packaging layer (10) from shaking in the housing (1) when the flexible capacitive pressure sensor moves, thereby facilitating the use of the flexible capacitive pressure sensor; S4: When the sealing capsule (11) is squeezed, the hydraulic oil (25) in the sealing capsule (11) enters the sealing chamber (28) through the conduit (27), thereby pushing the piston (29) to move, thereby driving the guide rod (32) to move, and further driving the arc-shaped movable plate (34) and the arc-shaped plate (31) to move, and finally, the two arc-shaped plates (31) clamp and fix the lead wire (37).

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