A method for screening the matrix sandwich dielectric layer for a capacitive pressure sensor and the capacitive pressure sensor itself.

Abstract

This invention relates to a method for screening lattice-core dielectric layers for capacitive pressure sensors and a capacitive pressure sensor in the field of sensor technology. It addresses the problem that traditional screening methods for capacitive pressure sensors are not suitable for testing dielectric layers using lattice-core structures. This invention obtains the slope of the pressure-strain curve of the lattice-core structure under arbitrary compressive strain. Based on the relationship between compressive strain and the capacitance of the capacitive pressure sensor, it determines the functional relationship between the slope of the pressure-strain curve and the sensitivity of the capacitive pressure sensor. The fluctuation and / or slope of the pressure-strain curve are used as indicators to screen lattice-core dielectric layers. This achieves detection-free screening of electrical performance, improves the screening efficiency of lattice-core dielectric layers, reduces screening costs, and simplifies the operation process.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a method for screening a dot matrix sandwich dielectric layer for a capacitive pressure sensor and a capacitive pressure sensor. Background Technology

[0002] Pressure sensors have advantages such as high sensitivity, fast response speed, high spatial resolution, and good flexibility and adaptability, and are widely used in many fields such as industry, medical care, and consumer electronics.

[0003] Traditional capacitive pressure sensors typically consist of two parallel metal electrodes and a dielectric layer in between. When external pressure is applied to the sensor, the thickness of the dielectric layer changes, leading to a change in capacitance. Pressure is measured by detecting this change in capacitance. However, such sensors have several limitations in practical applications. Traditional dielectric layers often use a single solid, microstructured flexible material with a small range of thickness variation. This restricts the sensor's deformation space along the thickness direction, resulting in low sensitivity and making it difficult to meet the pressure detection needs of different application scenarios. They are limited to a single sensing function.

[0004] The dot matrix sandwich structure has a flexible topological configuration. Using the dot matrix sandwich structure as the dielectric layer of the capacitive pressure sensor has a larger deformable space. Under pressure, it can produce significant deformation, resulting in greater changes in the thickness and dielectric constant of the dielectric layer. This solves the problem that traditional sensors have low sensitivity and cannot meet the pressure detection requirements of different application scenarios.

[0005] Currently, the industry primarily tests capacitive pressure sensors by directly measuring their electrical performance. This involves using specialized electrical testing equipment to individually examine the sensor's pressure-capacitance response curve, sensitivity, and other electrical parameters, then comparing these parameters with preset standard parameters to determine if the structure is suitable for the sensor's dielectric layer. However, this traditional trial-and-error screening method is not suitable for testing capacitive pressure sensors with a dot-matrix sandwich structure as the dielectric layer. There are several reasons for this:

[0006] First, the testing efficiency is low: the lattice sandwich structure usually contains dozens or even hundreds of lattice topology units, and there are many structural types of lattice topology units. It takes a lot of time to test the electrical parameters one by one. Especially in the case of mass production, the testing cycle is long and it is difficult to match the demand for efficient production, which greatly increases the production cost.

[0007] Secondly, the testing costs are high: specialized electrical testing equipment is expensive and requires regular calibration and maintenance. In addition, the testing process requires professional operators, which further increases the screening costs.

[0008] Third, the testing process is complex: before testing, the sensor needs to be accurately positioned and the electrodes connected. During the testing process, the testing environment (such as temperature and humidity) needs to be strictly controlled to avoid environmental factors from interfering with the test results of electrical parameters. The operation process is cumbersome and prone to human error.

[0009] Fourth, it can easily damage the sensor: During the detection process, operations such as electrode wiring and probe contact may cause mechanical damage to the sensor's electrodes and dielectric layer, causing the originally suitable structure to become unsuitable, resulting in missed detection of the structure.

[0010] Therefore, how to achieve low-cost, efficient, and easy-to-operate screening of dot matrix sandwich dielectric layers has become an urgent technical problem to be solved in the mass production of dot matrix capacitive pressure sensors. Summary of the Invention

[0011] In view of this, the present invention provides a method for screening the dielectric layer of a dot matrix sandwich structure for a capacitive pressure sensor and a capacitive pressure sensor. It establishes a corresponding correlation between the mechanical properties of the dot matrix sandwich structure and the electrical properties of the capacitive pressure sensor. The mechanical performance indicators of the dot matrix sandwich structure are tested using mechanical testing equipment. The mechanical performance indicators are then used to determine whether the dot matrix sandwich structure is suitable as a dielectric layer for a capacitive pressure sensor. This achieves screening of electrical performance without testing, improves the screening efficiency of the dot matrix sandwich dielectric layer, reduces screening costs, and simplifies the operation process.

[0012] The first aspect of this application provides a method for screening lattice sandwich dielectric layers for capacitive pressure sensors. The method involves obtaining the slope of the pressure-strain curve of the lattice sandwich structure under arbitrary compressive strain, determining the functional relationship between the slope of the pressure-strain curve and the sensitivity of the capacitive pressure sensor based on the relationship between compressive strain and capacitance of the capacitive pressure sensor, and screening the lattice sandwich dielectric layers based on the fluctuation and / or slope of the pressure-strain curve as indicators.

[0013] Furthermore, in the process of selecting the lattice sandwich dielectric layer based on the slope of the pressure-strain curve, the lattice sandwich structure with a stable and unfluctuating pressure-strain curve is selected as the dielectric layer of the capacitive pressure sensor.

[0014] Furthermore, the closer the slope of the pressure-strain curve is to 0, the more sensitive the pressure sensor is.

[0015] Furthermore, the functional relationship between the slope of the pressure-strain curve and the sensitivity of the capacitive pressure sensor is as follows: In the formula Let be the relative permittivity of the lattice sandwich structure when unloaded. For lattice sandwich structures under compressive strain The relative permittivity at this point, The dielectric constant of air is For compressive strain, The pressure P on the lattice sandwich structure under arbitrary compressive strain The derivative under pressure, i.e. the slope of the pressure-strain curve.

[0016] Furthermore, the process of determining the functional relationship between the slope of the pressure-strain curve and the sensitivity of the capacitive pressure sensor based on the relationship between compressive strain and capacitance of the capacitive pressure sensor includes:

[0017] First, based on the relationship between compressive strain and capacitance of the capacitive pressure sensor, the capacitance of the capacitive pressure sensor under arbitrary compressive strain is determined. The expression for the relative capacitance change is given below, and then based on the relative capacitance change and the pressure P and compressive strain of the lattice sandwich structure... The relationship is used to determine the functional relationship between the slope of the pressure-strain curve and the sensitivity of the capacitive pressure sensor.

[0018] Furthermore, the relationship between compressive strain and the capacitance of the capacitive pressure sensor is as follows:

[0019] ,

[0020] ,

[0021] ,

[0022] In the formula, A0 and d0 are the facing areas of the upper and lower electrodes and the distance between the upper and lower electrodes, respectively, when the pressure sensor is not under load. The dielectric constant of free space, This represents the volume fraction of the lattice sandwich structure under load. To determine the relative permittivity of the base material for preparing the lattice sandwich structure, This represents the distance between the upper and lower electrodes of the lattice sandwich structure under load.

[0023] Furthermore, capacitive pressure sensors can withstand arbitrary compressive strain. The expression for the relative capacitance change is as follows:

[0024] ,

[0025] in, This is the initial capacitance of the capacitive pressure sensor. For capacitive pressure sensors under arbitrary compressive strain The capacitor below, This represents the volume fraction of the lattice sandwich structure when it is not subjected to load.

[0026] Furthermore, the initial capacitance of the capacitive pressure sensor In the formula is the dielectric constant of free space; The relative permittivity of the lattice sandwich dielectric layer is given by: Let A0, d0, and d0 be the relative permittivity of the matrix material of the lattice sandwich structure; A0, d0, and d0 are the relative permittivity of the matrix material. These represent the area of ​​the upper and lower electrodes facing each other when the pressure sensor is not under load, the distance between the upper and lower electrodes, and the volume fraction of the dot matrix sandwich structure, respectively.

[0027] The second invention provides a capacitive pressure sensor employing a dot matrix sandwich dielectric layer, comprising an upper electrode, a lower electrode, wires, insulating material, and a dot matrix sandwich dielectric layer obtained by the screening method described in any one of claims 1 to 8; the upper electrode and the lower electrode are respectively disposed and fixed on the upper and lower surfaces of the dot matrix sandwich dielectric layer; there are two wires, which are respectively connected to the upper electrode and the lower electrode; there are two insulating materials, one disposed and fixed on the upper surface of the upper electrode, and the other disposed and fixed on the lower surface of the lower electrode.

[0028] Furthermore, the upper electrode and the lower electrode are metal foils pasted on the upper and lower surfaces of the lattice sandwich dielectric layer, or metal / non-metal conductive materials sprayed on the upper and lower surfaces of the lattice sandwich dielectric layer.

[0029] The beneficial effects of this invention compared to the prior art are:

[0030] 1. This invention establishes a functional relationship between the slope of the pressure-strain curve of the lattice sandwich dielectric layer and the sensitivity of the capacitive pressure sensor. It eliminates the need to perform electrical performance tests on each capacitive pressure sensor using the lattice sandwich dielectric layer. Screening can be completed simply by detecting the mechanical properties of the lattice sandwich dielectric layer. Compared with traditional electrical detection methods, this invention significantly shortens the single screening time, reduces production cycle costs, and greatly improves screening efficiency.

[0031] 2. This invention addresses the mechanical property testing of lattice sandwich dielectric layers. It eliminates the need for expensive specialized electrical testing equipment, requiring only conventional mechanical testing equipment, significantly reducing equipment procurement and maintenance costs. Furthermore, the testing operation is simple, eliminating the need for specialized electrical testing personnel, effectively reducing labor costs. In terms of simplifying the screening process, this method eliminates complex operations such as electrode wiring and precise positioning; only surface cleaning and fixation of the sample are required for testing. The low operational threshold effectively avoids human error and improves the accuracy of screening suitable sensor structures.

[0032] 3. This invention can flexibly adjust the dielectric layer structure for lattice sandwich structures with different topological configurations, and can adapt to the screening requirements of various regular lattices, disordered lattices and porous structures such as rod-shaped, plate-shaped and TPMS curved surfaces. It is also suitable for sensors with sandwich structures and filling materials, and can also be used for sandwich structures made of various materials. The manufacturing process can be 3D printing, interlocking assembly or traditional machining, etc., which has strong versatility. Attached Figure Description

[0033] The accompanying drawings, which form part of this invention, are provided to give a further understanding of the invention.

[0034] Figure 1 This is a schematic diagram of the overall structure of the capacitive pressure sensor of the present invention.

[0035] Figure 2 This is a schematic diagram of a capacitive pressure sensor using a dot-matrix sandwich dielectric layer.

[0036] Figure 3 This is a schematic diagram illustrating the principle of predicting the electrical performance of a capacitive pressure sensor based on the mechanical properties of a dot-matrix sandwich dielectric layer, as per the present invention.

[0037] Figure 4 This is a flowchart illustrating how the mechanical properties of a dot-matrix sandwich dielectric layer predict the electrical performance of a capacitive pressure sensor according to the present invention.

[0038] Figure 5 Verification diagrams for the mechanical and electrical tests of two capacitive pressure sensors employing Octet and Kelvin matrix sandwich structures.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Upper electrode; 2. Lower electrode; 3. Conductor; 4. Insulating material; 5. Lattice sandwich dielectric layer. Detailed Implementation

[0041] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Example 1:

[0043] Given the diverse types of dot matrix sandwich structures, this embodiment establishes a correlation between the mechanical properties of the dot matrix sandwich structure and the electrical properties of the capacitive pressure sensor to improve the sensitivity screening efficiency and reduce testing costs when used as the dielectric layer of a capacitive pressure sensor. The mechanical performance indicators of the dot matrix sandwich structure are tested using mechanical testing equipment. These indicators determine whether the dot matrix sandwich structure is suitable as the dielectric layer of a capacitive pressure sensor. If the indicators meet preset standards, the dot matrix sandwich structure is deemed suitable for capacitive pressure sensors; if the indicators do not meet the standards, it is deemed unsuitable for sensor fabrication. This method allows for indirect screening of the electrical performance of pressure sensors without requiring the assembly of each type of dot matrix sandwich structure into a sensor before electrical parameter testing. Specifically:

[0044] This embodiment provides a method for screening the dot matrix sandwich dielectric layer for a capacitive pressure sensor. The specific screening process is as follows:

[0045] S1, Obtain the lattice sandwich structure under arbitrary compressive strain The slope of the pressure-strain curve under these conditions :

[0046] S101, Preparation of various types of lattice sandwich structures: Using 3D modeling software such as Solidworks, various types of lattice sandwich structure models such as rod systems, plate bases, and TPMS curved lattices are constructed. Typical structures include Octet lattices and Kelvin lattices. After exporting the models as STL format files, additive manufacturing technologies such as SLS are used to complete the preparation of lattice sandwich structures with TPU as the substrate. The mechanical properties of the TPU substrate are: tensile modulus 75–85MPa, tensile strength 7–9MPa, and elongation at break 130%–280%.

[0047] S102, Pre-treatment of the lattice sandwich structure: After the structure is prepared, remove residual powder and other impurities from the surface to avoid interference with subsequent mechanical test results; at the same time, conduct an appearance quality inspection to remove samples with obvious defects such as damage, broken rods, and holes, reduce invalid tests, and ensure the reliability of subsequent test results.

[0048] S103, Mechanical property testing: The pre-treated lattice sandwich structure is placed on the worktable of a mechanical testing equipment such as an electronic material tensile testing machine. A pressure load is applied to it, and the pressure-strain response is recorded. This yields the pressure-strain curves corresponding to each lattice sandwich structure, and the slope of the curves is further extracted. As a key mechanical parameter.

[0049] S2, based on compressive strain The slope of the pressure-strain curve is determined by the capacitance relationship with the capacitive pressure sensor. Sensitivity of capacitive pressure sensors Functional relationship between them:

[0050] A capacitive pressure sensor works by applying external pressure, which deforms the dielectric layer structure of the sensor, altering the distance between electrodes and the dielectric constant during compression. This changes the capacitance, thus converting the pressure signal into an electrical signal. Therefore, the initial capacitance of the capacitive pressure sensor must first be determined. With compressive strain The capacitor below ;

[0051] The initial capacitance of a capacitive pressure sensor when no load is applied. for:

[0052] (1)

[0053] In the formula, A0 and d0 are the facing areas of the upper and lower electrodes and the distance between the upper and lower electrodes when the pressure sensor is not under load. The dielectric constant in free space is 8.85 × 10⁻⁶. −12 F / m; Since the lattice sandwich structure is a porous structure, the relative permittivity of the lattice sandwich dielectric layer is... The relative permittivity of the parent material used to prepare the lattice sandwich structure The dielectric constant of air Combining, that is In the formula This represents the volume fraction of the lattice sandwich structure when no load is applied. is the dielectric constant of air.

[0054] When a load is applied, the dielectric layer of the capacitive pressure sensor deforms, reducing the distance between the upper and lower electrodes. Simultaneously, air is expelled from the lattice core dielectric layer, thus affecting the relative permittivity of the dielectric layer at this time. At this time, the relative permittivity of the dielectric layer is In the formula The volume fraction of the lattice sandwich dielectric layer after applying load; capacitive pressure sensor under arbitrary compressive strain The capacitor below for:

[0055] (2)

[0056] (3)

[0057] In the formula, This represents the distance between the upper and lower electrodes of the lattice sandwich structure under load.

[0058] The capacitive pressure sensor under arbitrary compressive strain is obtained through formulas (1) and (2). The relative capacitance change is as follows:

[0059] (4)

[0060] In the formula, For arbitrary compressive strain The capacitance signal C under pressure and the capacitance under initial no pressure The difference;

[0061] Compressive strain There is a functional relationship between the pressure P exerted on the lattice sandwich structure and the pressure P. The core performance indicator for capacitive pressure sensors is their sensitivity. It can be represented as:

[0062] (5)

[0063] Substituting formula (4) into formula (5), we get:

[0064] (6)

[0065] In the formula The pressure P on the lattice sandwich structure under any strain The derivative under pressure, i.e., the pressure-strain curve The slope.

[0066] S3, assuming the external dimensions and materials of the capacitive pressure sensor are fixed, for a capacitive pressure sensor undergoing arbitrary compressive strain, the slope of the pressure-strain curve is... It is the sole key factor determining its sensitivity. If The sensitivity of the capacitive pressure sensor If it is a positive value; Then sensitivity It is a negative value; if Then sensitivity For infinity, such as Figure 3 As shown. In practical applications, the pressure on the sensor and the sensing response must satisfy a one-to-one linear relationship in order to accurately invert the magnitude of the external force based on the change in relative capacitance. Combining the derivation of formula (6), it can be seen that the pressure-strain curve of the lattice sandwich dielectric layer suitable for linear sensing must have a stable and unfluctuating plateau segment, and the slope within this interval must be... The pressure-strain curve slope should remain constant. Therefore, to improve the measurement accuracy and sensitivity of capacitive pressure sensors, the slope of the pressure-strain curve is preferred. A constant lattice sandwich structure approaching zero is used as the dielectric layer.

[0067] Therefore, this embodiment establishes a functional relationship between the slope of the pressure-strain curve of the lattice sandwich dielectric layer and the sensitivity of the capacitive pressure sensor. This eliminates the need to perform electrical performance tests on each capacitive pressure sensor using the lattice sandwich dielectric layer. Screening can be completed simply by detecting the mechanical properties of the lattice sandwich dielectric layer, thereby reducing production cycle costs and improving screening efficiency.

[0068] Example 2:

[0069] Based on the screening principle of the lattice sandwich structure in Example 1, the slope of the pressure-strain curve is selected. A capacitive pressure sensor using a constant and near-zero dot matrix sandwich structure as the dielectric layer is fabricated. The sensor mainly consists of an upper electrode 1, a lower electrode 2, wires 3, insulating material 4, and a dot matrix sandwich dielectric layer 5. The upper electrode 1 and lower electrode 2 are either metal electrode plates adhered to the upper and lower surfaces of the dot matrix sandwich dielectric layer 5, or metallic / non-metallic conductive materials sprayed onto the upper and lower surfaces of the dot matrix sandwich dielectric layer 5. When the upper electrode 1 and lower electrode 2 are metal electrode plates, they are fixed to the upper and lower surfaces of the dot matrix sandwich dielectric layer 5 respectively using adhesive. Two wires 3 are connected to the upper electrode 1 and lower electrode 2 respectively. Two sheets of insulating material 4 are fixed to the upper surface of the upper electrode 1 and the lower surface of the lower electrode 2 respectively using adhesive.

[0070] When the upper electrode 1 and lower electrode 2 are made of metal electrode plates, both are made of metallic materials, such as copper, gold, and silver, which have good conductivity. Copper electrodes are low-cost and have good conductivity, making them suitable for cost-sensitive industrial applications. Gold electrodes have excellent chemical stability, making them suitable for use in harsh environments such as humidity and corrosion, such as long-term implantable pressure monitoring in medical devices. Silver electrodes have among the highest conductivity metals, enabling faster and more accurate signal transmission, and can be used in consumer electronics where high response speed is required. The thickness of the electrodes can be adjusted according to actual needs, generally between 5-50 micrometers, to ensure good conductivity and structural stability. The electrodes connect to external circuits to detect capacitance changes; their shape can be designed as circular, square, or other irregular shapes, and the size can also be designed according to requirements. When the upper electrode 1 and lower electrode 2 are coated using a spraying method, the coating material can be a conductive material of either metal or non-metal. This process eliminates the need for electrode plate fabrication, improving sensor manufacturing efficiency.

[0071] The materials used to fabricate the lattice sandwich structure can be selected based on the specific application scenario. These materials can be high-dielectric-constant insulating materials, such as high-strength, low-density composites with good insulation properties, like carbon fiber reinforced polymers (CFRP), glass fiber reinforced polymers (GFRP), and ceramic matrix composites. Alternatively, materials with low stiffness, good flexibility, and good insulation properties can be used, such as thermoplastic polyurethane elastomers (TPU) and flexible resins. The lattice sandwich structure can be fabricated using 3D printing technology (such as photopolymerization and selective laser sintering) and microelectromechanical systems (MEMS) processing technology to ensure structural precision and consistency.

[0072] In addition, lattice sandwich structures can be used in conjunction with filler materials. The filler material fills the voids in the lattice sandwich structure, forming a dielectric layer together with the structure. The filler material should possess good mechanical properties and a certain dielectric constant, while also exhibiting good compatibility with the lattice sandwich structure material. Commonly used filler materials include flexible polymers such as silicone rubber, polyurethane, and polydimethylsiloxane (PDMS).

[0073] The wire 3 is used to connect the upper electrode 1, the lower electrode 2, and the external measuring circuit. It is made of a material with good conductivity and high flexibility, such as silver-plated copper wire or gold-plated copper wire. The diameter of the wire 3 can be selected according to the requirements. One end of the wire is connected to the electrode by welding or adhesive bonding, and the other end is connected to the external circuit.

[0074] This embodiment verifies the sensing performance of a capacitive pressure sensor that uses a dot-matrix sandwich structure as the dielectric layer:

[0075] Prepare two capacitive pressure sensors, one with an Octet matrix sandwich structure and the other with a Kelvin matrix sandwich structure. Connect the leads 3 of the two capacitive pressure sensors to an electrical testing instrument, such as an LCR meter, and measure the electrical signals of the two capacitive pressure sensors under compression. Figure 5 As shown, the pressure-strain curve of the capacitive pressure sensor with the Octet matrix sandwich structure oscillates and fluctuates greatly. Consequently, its electrical test results also exhibit oscillations and significant fluctuations, failing to meet the linear relationship of one-to-one correspondence between pressure and electrical signal, thus not meeting design requirements. Conversely, the pressure-strain curve of the capacitive pressure sensor with the Kelvin matrix sandwich structure is more stable and without fluctuations. Therefore, its electrical performance curve steadily increases, and a one-to-one correspondence between electrical signal and pressure exists. In subsequent use, the magnitude of force can be determined through the electrical signal, thus meeting the sensor's application requirements. Therefore, the effectiveness and correctness of the proposed method are verified.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions created by the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions created by the present invention without departing from the essence and scope of the technical solutions created by the present invention.

Claims

1. A method of screening dot matrix sandwich dielectric layers for capacitive pressure sensors, characterized by, Obtain the slope of the pressure-strain curve of the lattice sandwich structure under arbitrary compressive strain. Based on the relationship between compressive strain and capacitance of the capacitive pressure sensor, determine the functional relationship between the slope of the pressure-strain curve and the sensitivity of the capacitive pressure sensor. Use the fluctuation and / or slope of the pressure-strain curve as indicators to screen the dielectric layer of the lattice sandwich structure.

2. The method of claim 1, wherein the method is characterized by: In the process of selecting the lattice sandwich dielectric layer based on the slope of the pressure-strain curve, the lattice sandwich structure with a stable and unfluctuating pressure-strain curve is selected as the dielectric layer of the capacitive pressure sensor.

3. The method of claim 2, wherein the method is characterized by: The closer the slope of the pressure-strain curve is to 0, the more sensitive the pressure sensor is.

4. A method for screening the dot matrix sandwich dielectric layer for a capacitive pressure sensor according to claim 1 or 2, characterized in that, The function between the slope of the pressure-strain curve and the sensitivity of the capacitive pressure sensor is , wherein is the relative dielectric constant of the lattice sandwich structure when not under load, is the relative dielectric constant of the lattice sandwich structure under compression strain , is the dielectric constant of air, is the compression strain, is the derivative of the pressure P of the lattice sandwich structure with respect to the arbitrary compression strain , i.e. the slope of the pressure-strain curve.

5. The method of claim 4, wherein the method is characterized by: The process of determining the functional relationship between the slope of the pressure-strain curve and the sensitivity of the capacitive pressure sensor based on the relationship between compressive strain and capacitance of the capacitive pressure sensor includes: Firstly, the relative capacitance change expression of the capacitive pressure sensor under any compressive strain is determined based on the relationship between the compressive strain and the capacitance of the capacitive pressure sensor , and then the functional relationship between the slope of the pressure-strain curve and the sensitivity of the capacitive pressure sensor is determined based on the relative capacitance change and the relationship between the pressure P and the compressive strain of the lattice sandwich structure .

6. The method of claim 5, wherein the method is characterized by: The relationship between compressive strain and the capacitance of a capacitive pressure sensor is as follows: ， ， ， wherein A0 and d0 are the facing area of the upper and lower electrodes and the distance between the upper and lower electrodes when the pressure sensor is not subjected to a load, respectively, is the dielectric constant of free space, is the volume fraction of the lattice sandwich structure when subjected to a load, is the relative dielectric constant of the matrix material for preparing the lattice sandwich structure, is the distance between the upper and lower electrodes when the lattice sandwich structure is subjected to a load.

7. The method for screening the matrix sandwich dielectric layer for a capacitive pressure sensor according to claim 6, characterized in that, Capacitive pressure sensors under arbitrary compressive strain The expression for the relative capacitance change is as follows: ， in, This is the initial capacitance of the capacitive pressure sensor. For capacitive pressure sensors under arbitrary compressive strain The capacitor below, This represents the volume fraction of the lattice sandwich structure when it is not subjected to load.

8. The method for screening the dot matrix sandwich dielectric layer for a capacitive pressure sensor according to claim 7, characterized in that, Initial capacitance of a capacitive pressure sensor In the formula is the dielectric constant of free space; The relative permittivity of the lattice sandwich dielectric layer is given by: Let A0, d0, and d0 be the relative permittivity of the matrix material of the lattice sandwich structure; A0, d0, and d0 are the relative permittivity of the matrix material. These represent the area of ​​the upper and lower electrodes facing each other when the pressure sensor is not under load, the distance between the upper and lower electrodes, and the volume fraction of the dot matrix sandwich structure, respectively.

9. A capacitive pressure sensor employing a dot-matrix sandwich dielectric layer, characterized in that, It includes an upper electrode, a lower electrode, wires, insulating material, and a lattice sandwich dielectric layer obtained by the screening method described in any one of claims 1 to 8; the upper electrode and the lower electrode are respectively disposed and fixed on the upper and lower surfaces of the lattice sandwich dielectric layer; there are two wires, which are respectively connected to the upper electrode and the lower electrode; there are two pieces of insulating material, one of which is disposed and fixed on the upper surface of the upper electrode, and the other of which is disposed and fixed on the lower surface of the lower electrode.

10. A capacitive pressure sensor employing a dot-matrix sandwich dielectric layer according to claim 9, characterized in that, The upper and lower electrodes are metal foils pasted on the upper and lower surfaces of the lattice sandwich dielectric layer, or metal / non-metal conductive materials sprayed on the upper and lower surfaces of the lattice sandwich dielectric layer.

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