Capacitive pressure sensor and dual-mechanism relay sensing method thereof

Abstract

The invention discloses a capacitive pressure sensor and a dual-mechanism relay sensing method thereof. The sensor comprises a dielectric layer and an electrode layer, the dielectric layer comprises a first end face, a second end face and an elastic supporting structure, and the elastic supporting structure is arranged between the first end face and the second end face, so that an air gap exists in the dielectric layer; the electrode layers are of a porous structure and are arranged on the first end face and the second end face respectively. Any end face of the dielectric layer is provided with ion conductive gel, the ion conductive gel is in contact with the electrode layer arranged on the end face, and the thickness of the ion conductive gel is smaller than that of an air gap in the dielectric layer, so that a gap exists between the ion conductive gel and the electrode layer arranged on the other end face of the dielectric layer; when the sensor is pressed, the elastic supporting structure deforms, so that the distance between the two electrode layers is gradually reduced until the ion conductive gel is in contact with the electrode layer arranged on the other end face of the dielectric layer, and the relay between a traditional capacitance sensing mechanism and an ion electronic sensing mechanism is completed.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitive pressure sensors, and in particular to a capacitive pressure sensor and a dual-mechanism relay sensing method thereof. Background Art

[0002] The rapid development of many cutting-edge fields such as electronic skin and wearable textiles has promoted the technological innovation of sensing and interactive devices such as flexible pressure sensors. Among them, capacitive pressure sensors have attracted widespread attention from researchers and the industry because of their simple structure, high stability, low energy consumption, and small temperature drift. Capacitive pressure sensors are usually composed of two parallel electrodes and an elastic dielectric layer in the middle. Their working principle is to achieve pressure sensing by monitoring the capacitance change caused by the compression deformation of the dielectric layer.

[0003] At present, capacitive pressure sensors mainly use traditional capacitive sensing mechanisms and ionic electronic sensing mechanisms to achieve pressure sensing. For traditional capacitive pressure sensors, the capacitance value The capacitance change is mainly affected by the distance between the two electrodes. d ORD and the effective dielectric constant Influence, at this time, pressure sensing is mainly achieved by the change in capacitance caused by the longitudinal compression of the dielectric layer. For ionic capacitive pressure sensors, the capacitance value ,in and d EDL The change in the total capacitance value during the sensor compression process is not obvious, so the contact area between the electrode and the polymer electrolyte dielectric layer ( A EDL ) is the dominant factor in capacitance change.

[0004] Since sensitivity, sensing range and sensing linearity are the core indicators for evaluating pressure sensing performance, achieving the highest possible sensitivity within the widest possible linear sensing range is the ultimate goal of current product development. For traditional capacitive pressure sensors, researchers usually improve sensitivity by creating holes in the elastic dielectric layer or adding conductive fillers / dielectric fillers, taking advantage of the lower elastic modulus and larger dielectric constant change of the porous elastic matrix under pressure. For ionic capacitive pressure sensors, researchers usually use polymer electrolytes with high ionic conductivity and excellent mechanical properties as the dielectric layer, taking advantage of the polymer electrolyte's ability to form an electric double layer (EDL) capacitor with extremely high surface capacitance with the electrode surface, and by designing the surface microstructure of the dielectric layer and the electrode, increasing the variable contact area between the dielectric layer and the electrode surface under pressure (i.e., the area that can form the EDL) to improve sensitivity and sensing range.

[0005] For traditional capacitive pressure sensors, the too low Young's modulus limits the sensor's detection range; for ion capacitive pressure sensors, the large initial capacitance value also restricts the continuous improvement of sensitivity, and a simple ion capacitive pressure sensor is difficult to meet the requirements of a wide linear pressure sensing range.

[0006] Therefore, sensors that use the above two pressure sensing mechanisms alone cannot solve the balance problem between high sensitivity and wide linear sensing range. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a capacitive pressure sensor and a dual-mechanism relay sensing method thereof. The sensor combines the traditional capacitive sensing mechanism and the ionic electronic sensing mechanism, and realizes the relay triggering of the two sensing mechanisms through the elastic support structure inside the dielectric layer, the ionic conductive gel in contact with an electrode layer, and the electrode layer with a porous structure.

[0008] A first object of the present invention is to provide a capacitive pressure sensor, the sensor comprising a dielectric layer and an electrode layer; The dielectric layer comprises a first end face, a second end face and an elastic support structure, wherein the elastic support structure is arranged between the first end face and the second end face and is used to support the first end face and the second end face so that an air gap exists inside the dielectric layer, and the thickness of the air gap is greater than 0 and less than the thickness of the dielectric layer; The electrode layer is a porous structure, and the electrode layer is respectively arranged at the first end surface and the second end surface; An ion conductive gel is disposed at any end face of the dielectric layer, the ion conductive gel is in contact with the electrode layer disposed at the end face, and the thickness of the ion conductive gel is less than the thickness of the air gap inside the dielectric layer, so that there is a gap between the ion conductive gel and the electrode layer disposed at the other end face of the dielectric layer; When the sensor is under pressure, the elastic support structure deforms and the distance between the two electrode layers gradually decreases until the ion conductive gel contacts the electrode layer arranged at the other end of the dielectric layer, thereby completing the relay triggering of the traditional capacitive sensing mechanism and the ionic electronic sensing mechanism.

[0009] As a further improvement of the present invention, the porosity of the electrode layer is greater than 90%, and the specific surface area of ​​the electrode layer is greater than 10m 2 / g.

[0010] As a further improvement of the present invention, the compression elastic recovery rate of the elastic support structure is greater than or equal to 70%.

[0011] As a further improvement of the present invention, the elastic support structure is fixed between the first end surface and the second end surface of the dielectric layer by chemical bonding or physical hinge.

[0012] As a further improvement of the present invention, the elastic support structure can be manufactured by integrally forming with the first end surface and the second end surface of the dielectric layer.

[0013] As a further improvement of the present invention, the dielectric layer and the electrode layer are packaged into a whole by a packaging material, and the packaging material includes a PDMS film and a PI tape.

[0014] As a further improvement of the present invention, the initial capacitance value of the sensor when no pressure is applied is 1-100 pF.

[0015] The second object of the present invention is to provide a dual-mechanism relay sensing method, which is implemented based on the above-mentioned capacitive pressure sensor, and the method includes: In the low pressure stage, the elastic support structure inside the dielectric layer deforms, causing the thickness of the air gap inside the dielectric layer to gradually decrease, and the distance between the two electrode layers to gradually decrease, and the effective dielectric constant of the dielectric layer Gradually increase to enable sensing of low pressure stages through traditional capacitive sensing mechanisms; As the pressure increases, the elastic support structure inside the dielectric layer is completely compressed, and the air inside the dielectric layer is completely expelled. At this time, both electrode layers are in contact with the ion conductive gel, and a double-layer capacitor is formed between the two electrode layers. The sensing mechanism is transformed from the traditional capacitive sensing mechanism to the ionic electronic sensing mechanism, realizing the relay triggering of the sensing mechanism. Under the ionic electronic sensing mechanism, as the pressure further increases, the contact area between the ionic conductive gel and the two electrode layers increases to achieve sensing in the high pressure stage through the ionic electronic sensing mechanism.

[0016] As a further improvement of the present invention, when no pressure is applied, the internal circuit of the sensor is composed of a second ordinary capacitor. C ORD2 and the first double layer capacitance C EDL1 After being connected in series, it is then connected with the first common capacitor C ORD1 In parallel, the equivalent capacitance of the sensor is: ; Among them, the first double-layer capacitance C EDL1 is the capacitance between the ion conductive gel and the electrode layer configured at the end surface of the dielectric layer configured with the ion conductive gel, and the second common capacitance C ORD2 is the capacitance between the ion conductive gel and the electrode layer configured at the other end of the dielectric layer, the first common capacitance C ORD1 is the capacitance between the two electrode layers.

[0017] As a further improvement of the present invention, when the air inside the dielectric layer is completely exhausted, the ion conductive gel contacts the electrode layer configured at the other end of the dielectric layer and forms a double-layer capacitor, the internal circuit of the sensor is formed by the second double-layer capacitor. C EDL2 The first double layer capacitor C EDL1 After being connected in series, it is then connected with the first common capacitor C ORD1 In parallel, the equivalent capacitance of the sensor is: ; Among them, the second double layer capacitance C EDL2 It is the capacitance between the ion conductive gel and the electrode layer configured at the other end of the dielectric layer.

[0018] Compared with the prior art, the present invention has the following beneficial effects: Through the elastic support structure inside the dielectric layer, the ion conductive gel in contact with one electrode layer, and the porous structure electrode layer, the relay triggering of the traditional capacitive sensing mechanism and the ion electronic sensing mechanism is realized. In the low pressure stage, the deformation of the elastic support structure inside the dielectric layer is used to reduce the distance between the two electrode layers and change the dielectric constant of the dielectric layer, thereby realizing the pressure sensing in the low pressure stage by using the traditional capacitive sensing mechanism; after both electrode layers are in contact with the ion conductive gel, the sensing mechanism changes from the traditional capacitive sensing mechanism to the ion electronic sensing mechanism. Under the ion electronic sensing mechanism, as the pressure increases, the contact area between the electrode layer and the ion conductive gel gradually increases, thereby realizing the pressure sensing in the high pressure stage by using the ion electronic sensing mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of dual-mechanism relay sensing. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings: This embodiment provides a capacitive pressure sensor, the sensor comprising a dielectric layer and an electrode layer; The dielectric layer comprises a first end face, a second end face and an elastic support structure, wherein the elastic support structure is arranged between the first end face and the second end face and is used to support the first end face and the second end face so that an air gap exists inside the dielectric layer, and the thickness of the air gap is greater than 0 and less than the thickness of the dielectric layer; The electrode layer is a porous structure, and the electrode layer is respectively arranged at the first end surface and the second end surface; An ion conductive gel is arranged at any end face of the dielectric layer, the ion conductive gel is in contact with the electrode layer arranged at the end face, and the thickness of the ion conductive gel is less than the thickness of the air gap inside the dielectric layer, so that there is a gap between the ion conductive gel and the electrode layer arranged at the other end face of the dielectric layer.

[0022] The dielectric layer and the electrode layer are packaged into a whole by a packaging material, and the packaging material includes a PDMS film and a PI tape.

[0023] For conventional capacitive pressure sensors, the capacitance value The capacitance change is mainly affected by the distance between the two electrodes. d ORD and the effective dielectric constant Influence, at this time, pressure sensing is mainly achieved by generating capacitance changes through longitudinal compression of the dielectric layer.

[0024] The sensor provided in this embodiment has an elastic support structure inside its dielectric layer. When the sensor is not subjected to pressure, there is an air gap between the first end face and the second end face of the dielectric layer. At this time, the initial capacitance value of the sensor is 1~100pF, which can effectively eliminate the negative impact of the high initial capacitance value of traditional capacitive sensors on sensitivity.

[0025] When under pressure, the elastic support structure deforms, causing the thickness of the air gap inside the dielectric layer to gradually decrease, thereby reducing the distance between the two electrode layers, thereby meeting the variable distance between the two electrodes required by the traditional capacitive sensing mechanism. d ORD and the effective dielectric constant .

[0026] For ionic capacitive pressure sensors, the capacitance value ,in and d EDL The change in the total capacitance value during the sensor compression process is not obvious, so the contact area between the electrode and the polymer electrolyte dielectric layer ( A EDL ) is the dominant factor in capacitance change.

[0027] In the sensor provided in this embodiment, when the pressure it is subjected to reaches a certain value, both electrode layers are in contact with the ion conductive gel in the dielectric layer, thereby forming an electric double layer capacitor (EDL) inside the sensor. At this time, the sensing mechanism of the sensor changes from the traditional capacitive sensing mechanism to the ion electronic sensing mechanism, and as the pressure continues to increase, the contact area between the electrode layer and the ion conductive gel continues to increase, thereby realizing pressure sensing using the ion electronic sensing mechanism. Through the relay triggering of the two sensing mechanisms, a balance between high sensitivity and wide linear sensing range of the capacitive pressure sensor is achieved.

[0028] Ensure the normal operation of the traditional capacitive sensing mechanism: In the small pressure stage, the sensor relies on the bending deformation of the elastic support structure to change the distance between the two electrodes and the effective dielectric constant, thereby realizing the traditional capacitive sensing mechanism. The high elastic recovery rate allows the elastic support structure to effectively recover to a state close to the initial state after each compression deformation. This ensures that the electrode distance and the effective dielectric constant can change repeatedly and stably, so that the capacitance change generated by the sensor each time it is compressed is consistent and repeatable, thereby stabilizing the output of the sensing signal and ensuring the stable operation of the traditional capacitive sensing mechanism.

[0029] Furthermore, the compression elastic recovery rate of the elastic support structure is greater than or equal to 70%.

[0030] As the pressure increases, the change in the compression state of the elastic support structure is the key to triggering the transition of the sensing mechanism from traditional capacitive sensing to ionic electronic sensing. When the compression elastic recovery rate is greater than or equal to 70%, the deformation and recovery characteristics of the elastic support structure during the compression process are relatively stable, and the change in the thickness of the air gap inside the dielectric layer can be accurately controlled according to the pressure. When the air inside the dielectric layer is completely discharged, both electrode layers are in contact with the ionic conductive gel, thereby triggering the ionic electronic sensing mechanism, making the switching of the sensing mechanism more accurate and reliable.

[0031] At the same time, a high elastic recovery rate allows the elastic support structure to maintain good mechanical properties under long-term pressure cycles, making it less prone to fatigue damage, ensuring the integrity of the sensor's overall structure, ensuring the stability of the sensor's performance, and effectively extending the sensor's service life. For actual application scenarios, such as wearable devices, the sensor will frequently be subjected to varying degrees of pressure. A stable elastic recovery rate ensures that the pressure sensing function of the device is stable and reliable during long-term use, and will not cause measurement errors or failures due to the degradation of the elastic support structure's performance.

[0032] Furthermore, the elastic support structure is fixed between the first end surface and the second end surface of the dielectric layer by chemical bonding or physical hinge, or the elastic support structure and the first end surface and the second end surface of the dielectric layer are integrally formed.

[0033] Furthermore, in order to provide sufficient variable contact area under the ionic electronic sensing mechanism A EDL The electrode layer is a porous structure, and the porosity of the electrode layer is greater than 90%, and the specific surface area of ​​the electrode layer is greater than 10m 2 / g.

[0034] The ionic electronic sensing mechanism relies on the double-layer capacitance formed by the contact between the electrode and the ion conductive gel to achieve pressure sensing. As the pressure gradually increases, the contact area between the electrode and the ion gel surface gradually increases. The appropriate porosity and specific surface area enable the ion gel to more fully contact the electrode, significantly improving the sensing sensitivity and meeting the needs of a wide range of pressure detection.

[0035] The sensitivity of traditional capacitive sensors is generally less than 1 The detection range is lower than 10 kPa, and the sensitivity decreases continuously with the increase of pressure. Although the sensitivity of ion electronic sensors can reach 10~200 , but the detection range is usually below 100 kPa, and the sensitivity also decreases continuously with increasing pressure.

[0036] The capacitive sensor provided in this embodiment can realize pressure detection within the range of 0~1550 kPa, and can maintain 49.76 in the entire detection range. It has high sensitivity and high linearity of sensing, and the linear sensing interval accounts for 94.84% of the sensing range.

[0037] This embodiment provides a dual-mechanism relay sensing method, which is implemented based on the above-mentioned capacitive pressure sensor, and the method includes: In the low pressure stage, the elastic support structure inside the dielectric layer deforms, causing the thickness of the air gap inside the dielectric layer to gradually decrease, and the distance between the two electrode layers to gradually decrease, and the effective dielectric constant of the dielectric layer Gradually increase to enable sensing of low pressure stages through traditional capacitive sensing mechanisms; As the pressure increases, the elastic support structure inside the dielectric layer is completely compressed, and the air inside the dielectric layer is completely expelled. At this time, both electrode layers are in contact with the ion conductive gel, and a double-layer capacitor is formed between the two electrode layers. The sensing mechanism is transformed from the traditional capacitive sensing mechanism to the ionic electronic sensing mechanism, realizing the relay triggering of the sensing mechanism. Under the ionic electronic sensing mechanism, as the pressure further increases, the contact area between the ionic conductive gel and the two electrode layers increases to achieve sensing in the high pressure stage through the ionic electronic sensing mechanism.

[0038] The following combination Figure 1, specifically describes the structural change process of the capacitive sensor under different pressure stages and the equivalent circuit diagrams corresponding to different pressure stages.

[0039] In the figure, the dielectric layer consists of an upper end face, a lower end face and an elastic supporting structure arranged between the upper and lower end faces, and the upper and lower electrodes are respectively arranged at the upper and lower end faces of the dielectric layer; the ion conductive gel is arranged at the lower end face of the dielectric layer and contacts with the electrode layer arranged at the lower end face, and there is an air gap between the ion gel and the upper end face of the dielectric layer.

[0040] When no pressure is applied, the internal circuit of the sensor consists of a second common capacitor due to the air gap between the upper electrode and the ion gel. C ORD2 and the first double layer capacitance C EDL1 After being connected in series, it is then connected with the first common capacitor C ORD1 Parallel connection ( Figure 1 In the circuit diagram on the left), the equivalent capacitance value of the circuit (i.e. the sensor) is: ; Among them, the first double-layer capacitance C EDL1 is the capacitance between the ion conductive gel and the lower electrode, the second common capacitance C ORD2 is the capacitance between the ion conductive gel and the upper electrode, the first common capacitance C ORD1 is the capacitance between the two electrodes.

[0041] At this time, due to , so the equivalent capacitance value C total1 ≈ C ORD2 + C ORD1 , the initial capacitance value of the sensor is several orders of magnitude smaller than that of the ion capacitive pressure sensor.

[0042] When a small pressure is applied, the elastic support structure deforms and the distance between the two electrodes changes from the initial d Gradually shorten to d’ At the same time, the reduction of the air gap also causes the effective dielectric constant of the dielectric layer to The increase in the equivalent capacitance increases. Since the initial capacitance is small, the sensor has a high sensitivity in the small pressure stage.

[0043] As the pressure increases further, the elastic support structure is completely compressed, the air inside the dielectric layer is completely expelled, and the ion conductive gel contacts the upper electrode. At this time, the capacitance between the ion conductive gel and the upper electrode changes from the second ordinary capacitance toC ORD2 Transformed into a second double-layer capacitor with a higher capacitance per unit area C EDL2 The sensing mechanism changes from the traditional capacitive sensing mechanism to the ionic electronic sensing mechanism. At this time, the internal circuit of the sensor is composed of the second double-layer capacitor C EDL2 The first double layer capacitor C EDL1 After being connected in series, it is then connected with the first common capacitor C ORD1 In parallel, the equivalent capacitance of the circuit is: ; in, C EDL2 is the second double-layer capacitance between the ion gel and the upper electrode.

[0044] Similarly, due to , total capacitance C total2 ≈ C EDL1 × C EDL2 / ( C EDL1 + C EDL2 ). Thereafter, as the pressure increases further, the contact area between the electrode and the ion gel surface increases. A EDL As the pressure increases, the capacitance of the double-layer capacitor increases. Since both the upper and lower electrodes have a high specific surface area, a sufficiently large variable contact area is provided for the ion-electron sensing mechanism, ensuring a high sensitivity in the large pressure stage.

[0045] In the low-pressure stage, the deformation of the elastic support structure inside the dielectric layer is used to reduce the distance between the two electrode layers and change the dielectric constant of the dielectric layer, thereby using the traditional capacitive sensing mechanism to achieve pressure sensing in the low-pressure stage; after both electrode layers are in contact with the ion conductive gel, the sensing mechanism changes from the traditional capacitive sensing mechanism to the ion electronic sensing mechanism. Under the ion electronic sensing mechanism, as the pressure increases, the contact area between the electrode layer and the ion conductive gel gradually increases, thereby using the ion electronic sensing mechanism to achieve pressure sensing in the high-pressure stage. Through the relay triggering of the two sensing mechanisms, the pain point of the existing capacitive pressure sensor that it is difficult to achieve both high sensitivity and wide linear sensing range is solved.

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A capacitive pressure sensor, comprising a dielectric layer and an electrode layer, characterized in that: The dielectric layer comprises a first end face, a second end face and an elastic support structure, wherein the elastic support structure is arranged between the first end face and the second end face and is used to support the first end face and the second end face so that an air gap exists inside the dielectric layer; the thickness of the air gap is greater than 0 and less than the thickness of the dielectric layer; The electrode layer is a porous structure, and the electrode layer is respectively arranged at the first end surface and the second end surface; An ion conductive gel is disposed at any end face of the dielectric layer, the ion conductive gel is in contact with the electrode layer disposed at the end face, and the thickness of the ion conductive gel is less than the thickness of the air gap inside the dielectric layer, so that there is a gap between the ion conductive gel and the electrode layer disposed at the other end face of the dielectric layer; When the sensor is under pressure, the elastic support structure deforms and the distance between the two electrode layers gradually decreases until the ion conductive gel contacts the electrode layer arranged at the other end of the dielectric layer, thereby completing the relay triggering of the traditional capacitive sensing mechanism and the ionic electronic sensing mechanism.

2. The capacitive pressure sensor according to claim 1, characterized in that: The porosity of the electrode layer is greater than 90%, and the specific surface area of ​​the electrode layer is greater than 10m 2 / g.

3. The capacitive pressure sensor according to claim 1, characterized in that: The compression elastic recovery rate of the elastic support structure is greater than or equal to 70%.

4. The capacitive pressure sensor according to claim 1, characterized in that: The elastic support structure is fixed between the first end surface and the second end surface of the dielectric layer by chemical bonding or physical hinge.

5. The capacitive pressure sensor according to claim 1, characterized in that: The elastic support structure can be manufactured by integrally forming with the first end surface and the second end surface of the dielectric layer.

6. The capacitive pressure sensor according to claim 1, characterized in that: The dielectric layer and the electrode layer are packaged into a whole by a packaging material, and the packaging material includes a PDMS film and a PI tape.

7. The capacitive pressure sensor according to claim 1, characterized in that: The initial capacitance value of the sensor when no pressure is applied is 1-100 pF.

8. A dual-mechanism relay sensing method, implemented based on the capacitive pressure sensor according to any one of claims 1 to 7, the method comprising: In the low pressure stage, the elastic support structure inside the dielectric layer deforms, causing the thickness of the air gap inside the dielectric layer to gradually decrease, and the distance between the two electrode layers to gradually decrease, and the effective dielectric constant of the dielectric layer Gradually increase to enable sensing of low pressure stages through traditional capacitive sensing mechanisms; As the pressure increases, the elastic support structure inside the dielectric layer is completely compressed, and the air inside the dielectric layer is completely expelled. At this time, both electrode layers are in contact with the ion conductive gel, and a double-layer capacitor is formed between the two electrode layers. The sensing mechanism is transformed from the traditional capacitive sensing mechanism to the ionic electronic sensing mechanism, realizing the relay triggering of the sensing mechanism. Under the ionic electronic sensing mechanism, as the pressure further increases, the contact area between the ionic conductive gel and the two electrode layers increases to achieve sensing in the high pressure stage through the ionic electronic sensing mechanism.

9. The method according to claim 8, characterized in that When no pressure is applied, the sensor internal circuit is composed of a second common capacitor C ORD2 and the first double layer capacitance C EDL1 After being connected in series, it is then connected with the first common capacitor C ORD1 In parallel, the equivalent capacitance of the sensor is: ； Among them, the first double-layer capacitance C EDL1 is the capacitance between the ion conductive gel and the electrode layer configured at the end surface of the dielectric layer configured with the ion conductive gel, and the second common capacitance C ORD2 is the capacitance between the ion conductive gel and the electrode layer configured at the other end of the dielectric layer, the first common capacitance C ORD1 is the capacitance between the two electrode layers.

10. The method according to claim 8, characterized in that When the air inside the dielectric layer is completely exhausted and the ion conductive gel contacts the electrode layer configured at the other end of the dielectric layer to form a double-layer capacitor, the internal circuit of the sensor is connected by the second double-layer capacitor. C EDL2 The first double layer capacitor C EDL1 After being connected in series, it is then connected with the first common capacitor C ORD1 In parallel, the equivalent capacitance of the sensor is: ； Among them, the second double layer capacitance C EDL2 It is the capacitance between the ion conductive gel and the electrode layer configured at the other end of the dielectric layer.

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