Capacitive pressure sensor core body, preparation method thereof and capacitive pressure sensor

Abstract

The invention provides a capacitive pressure sensor core, a preparation method thereof and a capacitive pressure sensor. Specifically, the capacitive pressure sensor core comprises a deformable diaphragm, a ceramic substrate and a capacitive performance transducer. The capacitive performance transducer comprises a first electrode comprising a first measuring electrode part and a first capacitive shielding electrode part, a second electrode comprising a second measuring electrode part and a second capacitive shielding electrode part, and a gap separator, wherein the first measuring electrode part comprises a first measuring electrode central part, the second measuring electrode part comprises a second measuring electrode central part, and the area of the first measuring electrode central part is smaller than that of the second measuring electrode central part; wherein the first measuring electrode part, the first capacitance shielding electrode part, the second measuring electrode part and the second capacitance shielding electrode part are formed by reducing and sintering organic metal conductor paste.

Description

Technical Field

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

[0002] Pressure sensors can be divided into strain gauge, piezoresistive, capacitive, inductive, piezoelectric, and resonant pressure sensors based on their structure and working principle. A piezoresistance sensor converts changes in pressure into corresponding changes in capacitance. Through a detection circuit, the change in capacitance can be converted into electrical signal outputs such as frequency, current, and voltage. Among them, ceramic capacitive pressure sensors are widely used in automobiles, including automotive heat pump air conditioning systems, engine systems, transmission systems, and commercial vehicle braking systems. A pressure sensor is a sensor element that converts external mechanical signals into electrical signals by causing the sensitive membrane layer to change in winding or pressure. The core component of this element is the internal ceramic core.

[0003] For example, patent CN112834084A discloses a ceramic capacitive pressure sensor core and a manufacturing method. The pressure sensor core includes: a first substrate, a second substrate, a first electrode, a second electrode, an isolation pier, a first lead hole, a second lead hole, and a third lead hole. The thickness of the first electrode of the core is 5-8 μm, and the isolation pier of the core is printed on the edge of the first electrode with a printing thickness of 30-50 μm. The electrode thickness in this core is relatively large, and the electrode as a sensitive diaphragm is prone to cracking and brittle phases, resulting in reduced reliability. In addition, the isolation pier in this patent, as a material for sealing the two substrates and a factor for controlling the distance between the two electrodes, has poor flexibility and the thickness d of the gap isolation member is relatively high, resulting in nonlinear drift and reduced sensitivity of the core during the pressure sensing process.

[0004] For example, patent CN111693186A discloses a method for preparing a ceramic capacitive pressure sensor electrode. The thickness of the gold electrode is controlled by adjusting the viscosity of the gold paste, the gold particle content, the number of screen printing times, and the mesh size of the screen. The core electrode is prepared through a suitable sintering process. This invention uses gold nanoparticles, which are costly. In addition, the presence of a non-uniform single phase leads to pores at the interface, affecting product reliability.

[0005] For example, patent CN218724903U discloses a ceramic capacitive pressure sensor that uses a shielding ring design to form a shielding cover, which can shield the parasitic capacitance of the conductive liquid being measured and protect the initial capacitance of the pressure sensing element ceramic capacitor from being affected by the parasitic capacitance of conductive liquids such as water. This solves the problem of inaccurate pressure detection of conductive liquids such as water by ceramic capacitive pressure sensors, and improves the accuracy of pressure detection of conductive liquids such as water by ceramic capacitive pressure sensors. However, the electrode design of this patent has a design defect of facing area. The effective electrode area inside the first electrode shielding ring is basically the same as the effective area of the electrode inside the second electrode shielding ring, and the effect of the effective facing area on sensitivity is not considered.

[0006] In the existing technology, the electrode slurry is made of pure gold particle powder, organic solvent and resin in a certain proportion, which is costly. It is also a non-uniform single phase. After sintering, there are pores inside the electrode, resulting in poor bonding with the ceramic substrate. The surface roughness of the produced electrode is large, resulting in poor reliability and unstable performance. In addition, the design of the electrode inside the core in the existing technology still has limitations and shortcomings, including the difficulty of silk screen positioning and the disadvantage of nonlinear offset of capacitance value after pressurization. Summary of the Invention

[0007] The purpose of this application is to provide a capacitive pressure sensor core, a preparation method thereof, and a capacitive pressure sensor, aiming to solve the problems of poor bonding between the existing electrode slurry and the ceramic substrate, poor reliability and unstable performance of the obtained electrodes, and the difficulty in silk screen positioning and nonlinear offset of the capacitance value after pressurization in the design of the internal electrodes of the core in the prior art.

[0008] In a first aspect, a capacitive pressure sensor core is provided, comprising:

[0009] Deformable diaphragm;

[0010] a ceramic substrate, a cavity being formed between a central region of a top surface of the deformable diaphragm and a central region of a bottom surface of the ceramic substrate, the top surface of the ceramic substrate having a through hole for inserting a metal lead; and

[0011] A capacitive performance transducer for detecting pressure-dependent deformation of a deformable diaphragm, comprising:

[0012] a first electrode formed on a central area of a bottom surface of the ceramic substrate corresponding to the cavity, and

[0013] comprising a first measuring electrode portion and a first capacitive shielding electrode portion;

[0014] a second electrode facing the first electrode and formed on a top surface of the deformable diaphragm corresponding to the cavity, and including a second measuring electrode portion and a second capacitive shielding electrode portion; and

[0015] a gap spacer disposed between the first electrode and the second electrode;

[0016] wherein the first measuring electrode portion includes a first measuring electrode central portion, and the second measuring electrode portion includes a second measuring electrode central portion, and an area of the first measuring electrode central portion is smaller than an area of the second measuring electrode central portion;

[0017] The first measuring electrode portion, the first capacitive shielding electrode portion, the second measuring electrode portion, and the second capacitive shielding electrode portion are formed by reduction-sintering an organic metal conductor paste.

[0018] In the present application, the first electrode and the second electrode are prepared by using an organic metal conductor slurry. In the organic metal conductor slurry, the metal element is combined with other elements in the slurry in the form of a chemical bond. The entire system is evenly dispersed and can be smoothly and continuously covered on the deformable diaphragm and the ceramic substrate during the preparation process. The process of converting the metal element from the state of metal ions to metal elements after high-temperature reduction sintering makes the prepared metal electrode more firmly bonded to the deformable diaphragm and the ceramic substrate. The electrode prepared by the organic metal conductor slurry has a dense film, a thin film and a smooth surface, which can effectively reduce the impact on the output of the capacitance signal caused by the cracking of the electrode due to the deflection during the operation of the core body, and can significantly improve the reliability and stability of the product. In addition, compared with the traditional core preparation process, since the surface of the electrode prepared in this application is smooth, the grinding and polishing process can be simplified, thereby improving production efficiency.

[0019] In addition, because the electrodes prepared from the organic metal conductor slurry of the present application are denser and have a smoother surface, the internal effective electrode area in the first electrode of the present application can be significantly reduced during the design process. When the same capacitance value is output, reducing the effective facing area can reduce the variation range of the gap value, thereby improving the sensitivity of the core during operation, and can reduce the deflection range of the core film while reducing the thickness of the gap isolation member, thereby improving the product life.

[0020] Optionally, the ratio of the area of the central portion of the first measuring electrode to the area of the central portion of the second measuring electrode is 0.34-0.42:1.

[0021] Optionally, the first capacitive shielding electrode portion includes a first capacitive shielding electrode annular portion, a first capacitive shielding electrode extension portion and a first capacitive shielding electrode point portion, the first capacitive shielding electrode annular portion is a ring with an opening and surrounds the outer circumference of the central portion of the first measuring electrode, the first capacitive shielding electrode extension portion extends outward from both ends of the opening, and the first capacitive shielding electrode point portion is connected to the first capacitive shielding electrode extension portion and is electrically connected to the metal lead.

[0022] Optionally, the second capacitive shielding electrode portion includes a second capacitive shielding electrode annular portion, a second capacitive shielding electrode extension portion and a second capacitive shielding electrode point portion, the second capacitive shielding electrode annular portion is a ring with an opening and surrounds the outer circumference of the center portion of the second measuring electrode, the second capacitive shielding electrode extension portion extends outward from both ends of the opening, and the second capacitive shielding electrode point portion is connected to the second capacitive shielding electrode extension portion and is electrically connected to the metal lead.

[0023] Furthermore, the parasitic capacitance shielding design in the first electrode and the second electrode of the present application adopts a non-closed-loop point-shaped ending type to connect the metal pins to the external circuit. Due to the wide distribution of linear features, the use of high-precision CCD (charge-coupled device) cameras and image processing technology requires processing more pixel data. The excellent effect of the point-shaped ending type is that it does not affect the shielding function, reduces the difficulty of CCD recognition during the silk screen printing process (that is, using high-precision CCD cameras and image processing technology) to improve positioning accuracy, thereby improving the silk screen printing yield.

[0024] Optionally, the organic metal conductor paste includes at least two of an organic metal polymer, an organic solvent, a thixotropic agent, a thickener, and a dispersant.

[0025] Optionally, the organic metal conductor paste comprises, by weight percentage, 5% to 30% of an organic metal polymer, 10% to 40% of an organic solvent, 10% to 30% of a thixotropic agent, 10% to 30% of a thickener, and 5% to 10% of a dispersant.

[0026] Optionally, the organometallic polymer is an organic gold polymer, an organic silver polymer, an organic copper polymer, or an organic platinum polymer; and / or the organic solvent is one or more of terpineol, butyl acetate, ethylene glycol monobutyl ether, butyl carbitol acetate, and dibutyl phthalate.

[0027] Optionally, the thixotropic agent is selected from one or more of polyamide wax, polyurea, magnesium silicate, and hydrogenated castor oil.

[0028] Optionally, the thickener is selected from one or more of ethyl cellulose, dibutyl phthalate, dioctyl phthalate, and triethanolamine.

[0029] Optionally, the dispersant is selected from one or more of polyvinyl pyrrolidone, hexadecyltrimethylammonium bromide, sodium citrate decahydrate, sodium dodecylbenzenesulfonate, Tween 20, and Span 80.

[0030] Optionally, the organometallic polymer is a metal resin acid, which is prepared by reacting a metal chloride with any one of a thiol and a sulfurized balsam, the thiol is selected from one or more of tert-dodecyl mercaptan, n-dodecyl mercaptan, p-tert-butylbenzyl mercaptan, and decanedithiol, and the sulfurized balsam is selected from one or more of sulfurized turpentine, sulfurized copaiba balsam, and sulfurized terpenes.

[0031] Optionally, the organometallic polymer is a coordination polymer formed by the complexation of a homopolymer or copolymer with a metal, the homopolymer being formed by homopolymerizing 2-methyl-2-thiopyranylmethyl acrylate as a monomer, and the copolymer being formed by copolymerizing 2-methyl-2-thiopyranylmethyl acrylate and a monomer mixture selected from one or more of the following: methyl methacrylate, tert-butyl methacrylate, vinyl acetate, styrene, hydroxyethyl methacrylate, acrylamide, and diphenyl sulfoxide.

[0032] Optionally, the thickness of the gap spacer is between 10 μm and 20 μm.

[0033] In a second aspect, a method for preparing a capacitive pressure sensor core is also provided, comprising:

[0034] Provide ceramic substrate and deformable diaphragm;

[0035] preparing an organic metal conductor slurry;

[0036] Printing, coating, or depositing an organic metal conductor paste on the ceramic substrate and the deformable membrane according to the patterns of the first electrode and the second electrode, respectively, to prepare a first electrode precursor and a second electrode precursor;

[0037] performing reduction sintering on the first electrode precursor and the second electrode precursor; and

[0038] The reduction-sintered ceramic substrate and the deformable diaphragm are joined in a compression-tight manner.

[0039] Optionally, the step of bonding the reduction-sintered ceramic substrate and the deformable diaphragm in a compression-tight manner includes:

[0040] After reduction sintering the first electrode precursor and the second electrode precursor, placing the reduction sintered ceramic substrate in a metal mold, printing the encapsulation slurry on the ceramic substrate with the first electrode pattern through a designed printing pattern, and then sealing and sintering to form a gap spacer; and

[0041] Epoxy silver paste is injected into the through holes on the top surface of the ceramic substrate and metal pins are inserted, followed by a curing process.

[0042] Optionally, the reduction sintering is performed at a temperature of 800° C. to 1000° C., the reduction sintering time is 5 minutes to 15 minutes, and the heating rate is between 3° C. / min and 10° C. / min.

[0043] Optionally, the curing temperature is 150° C. to 300° C., and the curing time is 5 minutes to 15 minutes.

[0044] In a third aspect, a capacitive pressure sensor is provided, comprising:

[0045] The capacitive pressure sensor core as described above, or the capacitive pressure sensor core prepared according to the method described above; and

[0046] The external circuit is connected to the capacitive pressure sensor core through metal pins.

[0047] Therefore, the electrode prepared by the organic metal conductor slurry of the present application has a thin dense film and a smooth surface, which can effectively reduce the impact of electrode cracking caused by deflection during the core operation on the output of the capacitance signal, and can significantly improve the reliability and stability of the product. In addition, compared with the traditional core preparation process, the smooth surface of the electrode prepared by the present application can simplify the grinding and polishing process and improve production efficiency. Furthermore, the parasitic capacitance shielding design in the first electrode and the second electrode of the present application adopts a non-closed loop point-shaped end-type connection metal pin to the external circuit. Combined with the organic metal conductor slurry of the present application, it can reduce the difficulty of CCD recognition during the screen printing process and improve positioning accuracy without affecting the shielding function, thereby improving the screen printing yield. In addition, because the electrode prepared by the organic metal conductor slurry of the present application is denser and has a smoother surface, the internal effective electrode area of the first electrode in the present application is significantly reduced in design. When the same capacitance value is output, reducing the effective facing area can reduce the variation range of the gap value to improve the sensitivity of the core during work, and can reduce the thickness of the gap spacer while reducing the deflection range of the core film, thereby improving the product life. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0049] Figure 1A schematic diagram of electrodes of a capacitive pressure sensor core in the prior art;

[0050] Figure 2 A three-dimensional diagram of the capacitive pressure sensor core of the present application;

[0051] Figure 3 This is an exploded view of the capacitive pressure sensor core of the present application;

[0052] Figure 4 A schematic diagram of the electrode pattern of the first electrode of the capacitive pressure sensor core of the present application;

[0053] Figure 5 A schematic diagram of the electrode pattern of the second electrode of the capacitive pressure sensor core of the present application;

[0054] Figure 6 This is a flowchart of a method for preparing a capacitive pressure sensor core according to the present application;

[0055] Figure 7A A scanning electron microscope image of the interface between the electrode and the ceramic substrate in the capacitive pressure sensor core manufactured by the comparative example is shown;

[0056] Figure 7B A scanning electron microscope image of the interface between the electrode and the ceramic substrate in the capacitive pressure sensor core manufactured by Example 1 is shown;

[0057] Figure 8 A graph showing the change in capacitance value of the capacitive pressure sensor cores manufactured by Example 1 and Example 2 as a function of pressure is shown. DETAILED DESCRIPTION

[0058] In the embodiments of the present application, the terms "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, a feature specified as "first," "second," "third," "fourth," "fifth," and "sixth" may explicitly or implicitly include one or more of the features.

[0059] In the embodiments of the present application, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0060] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0061] As used herein, the phrase "at least one of" following a list of items, along with the terms "and" or "or" used to separate any of those items, modifies the list as a whole, rather than modifying each element of the list (e.g., each item). The phrase "at least one of" does not require selection of at least one item; rather, the phrase is meant to include at least one of any of the items, and / or at least one of any combination of those items, and / or at least one of each of the items. As an example, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" each refers to: only A, only B, or only C; any combination of A, B, and C; and / or at least one of each of A, B, and C.

[0062] I. Capacitive pressure sensor core

[0063] Pressure sensors can be divided into strain gauge, piezoresistive, capacitive, inductive, piezoelectric, and resonant pressure sensors based on their structure and working principle. A piezoresistance sensor converts changes in pressure into corresponding changes in capacitance. Through a detection circuit, the change in capacitance can be converted into electrical signal outputs such as frequency, current, and voltage. Among them, ceramic capacitive pressure sensors are widely used in automobiles, including automotive heat pump air conditioning systems, engine systems, transmission systems, and commercial vehicle braking systems. A pressure sensor is a sensor element that converts external mechanical signals into electrical signals by causing the sensitive membrane layer to change in winding or pressure. The core component of this element is the internal ceramic core.

[0064] like Figure 1 As shown, the capacitive pressure sensor core of the prior art forms a compensation capacitance signal by designing an annular shielding ring around the measuring capacitance. Since the initial value of the compensation capacitance is the same as the initial value of the measuring capacitance, the measuring capacitance and the compensation capacitance are affected by the same amount of electromagnetic radiation interference and parasitic capacitance. The capacitance value between the measuring electrodes is compensated by the real-time capacitance difference between the measuring electrode and the compensation electrode to eliminate the influence of the edge effect. The capacitance value between the measuring electrodes is compensated by the difference between the initial value of the compensation electrode and its real-time value, which can effectively eliminate external influences such as electromagnetic radiation, parasitic capacitance and coupling capacitance, thereby achieving stable pressure measurement.

[0065] However, the existing annular shielding electrode has a wide distribution of linear features, and the use of high-precision CCD (charge-coupled device) cameras and image processing technology requires processing more pixel data. The CCD recognition difficulty and positioning accuracy during the silk screen printing process are not high, resulting in poor silk screen printing yield.

[0066] In addition, patent CN111693186A discloses a method for preparing a ceramic capacitive pressure sensor electrode, which regulates the thickness of the gold electrode by adjusting the viscosity of the gold paste, the gold particle content, the number of screen printing times, and the mesh size of the screen, and prepares the core electrode through a suitable sintering process. This invention uses gold nanoparticles, which are costly; and the presence of a non-uniform single phase will cause pores at the interface, affecting product reliability.

[0067] In view of the above problems existing in the prior art, the present application provides a capacitive pressure sensor core, such as Figure 2 and Figure 3 As shown, the capacitive pressure sensor core comprises a deformable diaphragm 1, a ceramic substrate 2, and a capacitive performance transducer. A cavity is formed between the central region of the top surface of the deformable diaphragm 1 and the central region of the bottom surface of the ceramic substrate 2. The top surface of the ceramic substrate 2 has a through-hole 6 for inserting a metal lead 7. The capacitive performance transducer is used to detect the pressure-dependent deformation of the deformable diaphragm 1 and comprises a first electrode 3, a second electrode 4, and a gap spacer 5. The first electrode 3 is formed on the central region of the bottom surface of the ceramic substrate 2 corresponding to the cavity. The second electrode 4 faces the first electrode 3 and is formed on the top surface of the deformable diaphragm 1 corresponding to the cavity. The gap spacer 5 is sandwiched between the first electrode 3 and the second electrode 4.

[0068] Figure 4 FIG. 4 shows the electrode pattern of the first electrode 3. Figure 4 As shown, the first electrode 3 includes a first measuring electrode portion and a first capacitive shielding electrode portion. The first measuring electrode portion includes a first measuring electrode central portion 3-1, a first measuring electrode extension portion 3-2, and a first measuring electrode point portion 3-3. The first measuring electrode central portion 3-1 and the first measuring electrode point portion 3-3 are electrically connected via the first measuring electrode extension portion 3-2. The first measuring electrode point portion 3-3 is formed as a pad for connecting to a measuring metal pin. The first capacitive shielding electrode portion includes a first capacitive shielding electrode ring portion 3-4, a first capacitive shielding electrode extension portion 3-5, and a first capacitive shielding electrode point portion 3-6. The first capacitive shielding electrode ring portion 3-4 is annular with an opening and surrounds the outer circumference of the first measuring electrode central portion 3-1. The first capacitive shielding electrode extension portion 3-5 extends outward from both ends of the opening. The first capacitive shielding electrode point portion 3-6 is connected to the first capacitive shielding electrode extension portion 3-5 and forms a pad electrically connected to the metal lead.

[0069] Figure 5 FIG. 4 shows the electrode pattern of the second electrode 4. Figure 5As shown, the second electrode 4 includes a second measuring electrode portion and a second capacitive shielding electrode portion. The second measuring electrode portion includes a second measuring electrode central portion 4-1, a second measuring electrode extension portion 4-2, and a second measuring electrode point portion 4-3. The second measuring electrode central portion 4-1 and the second measuring electrode point portion 4-3 are electrically connected via the second measuring electrode extension portion 4-2. The second measuring electrode point portion 4-3 forms a pad for connecting to a measuring metal pin. The second capacitive shielding electrode portion includes a second capacitive shielding electrode ring portion 4-4, a second capacitive shielding electrode extension portion 4-5, and a second capacitive shielding electrode point portion 4-6. The second capacitive shielding electrode ring portion 4-4 is annular with an opening and surrounds the outer circumference of the second measuring electrode central portion 4-1. The second capacitive shielding electrode extension portion 4-5 extends outward from both ends of the opening. The second capacitive shielding electrode point portion 4-6 is connected to the second capacitive shielding electrode extension portion 4-5 and forms a pad electrically connected to the metal lead.

[0070] In the present application, the parasitic capacitance shielding design in the first electrode 3 and the second electrode 4 adopts a non-closed-loop point-shaped ending type to connect the metal pins to the external circuit. Since the linear features are widely distributed, the CCD needs to process more pixel data. The excellent effect of the point-shaped ending type is that it does not affect the shielding function, reduces the difficulty of CCD recognition during the silk screen printing process, improves positioning accuracy, and thus improves the silk screen printing yield.

[0071] In some embodiments, the deformable diaphragm 1 and the ceramic substrate 2 may be made of ZTA ceramics or silicon nitride ceramics.

[0072] In some embodiments, the first measuring electrode portion, the first shielding electrode portion, the second measuring electrode portion, and the second shielding electrode portion are formed by reduction-sintering an organic metal conductor paste.

[0073] In some embodiments, the organometallic conductor paste includes at least two of an organometallic polymer, an organic solvent, a thixotropic agent, a thickener, and a dispersant. By way of example and not limitation, the organometallic conductor paste includes, by weight, 5% to 30% of an organometallic polymer, 10% to 40% of an organic solvent, 10% to 30% of a thixotropic agent, 10% to 30% of a thickener, and 5% to 10% of a dispersant.

[0074] The organometallic polymer may be a coordination polymer of a polymer and a metal, specifically, a coordination polymer formed by complexing a polymer containing thioether or thiol functional groups with a metal ion. By way of example and not limitation, the metal conductor may be selected from conductive metals such as gold, silver, copper, and platinum, thereby forming an organogold polymer, an organogold polymer, an organogold copper polymer, or an organogold platinum polymer.

[0075] In some embodiments, the organometallic polymer is a metal resin acid. By way of example and not limitation, the metal resin acid is prepared by reacting a metal chloride with any one of a mercaptan and a sulfurized balsam. By way of example and not limitation, the mercaptan is selected from one or more of tert-dodecyl mercaptan, n-dodecyl mercaptan, p-tert-butylbenzyl mercaptan, and decanedithiol. By way of example and not limitation, the sulfurized balsam is selected from one or more of sulfurized turpentine, sulfurized copaiba balsam, and sulfurized terpenes.

[0076] In the above embodiment, the present invention uses resin acid gold prepared by the reaction of metal chloride and thiol as an example to illustrate the preparation method of metal resin acid, which includes: dissolving chloroauric acid in ethanol, and the pH value of the solution is 3.5 to 5.5; then adding thioether to the solution to prepare a solution with a molar ratio of chloroauric acid to thioether of 1: (1.2-1); stirring the mixed solution of chloroauric acid and thioether obtained in the above step at 50° C. to 70° C. for 2 to 4 hours, then adding thiol to the solution, and the molar ratio of chloroauric acid to thiol is 1: (1.2-1), and continuing to react at 50° C. to 70° C. for 2 to 4 hours; filtering to obtain a precipitate; washing it with ethanol several times, and then vacuum drying it at 50° C. to 60° C. for 1 to 2 hours to obtain an organic gold precursor; and taking the above organic gold precursor and an organic solvent to prepare a metal resin acid.

[0077] In the above embodiment, the present invention uses a gold resinate prepared by reacting a metal chloride with sulfur balsam as an example to illustrate a method for preparing a metal resinate, which comprises: dissolving gold chloride having an acidity of 2-8% in isopropyl alcohol to prepare a solution having a gold chloride content (by weight) of 20-30%, pouring the above solution into sulfur balsam having a sulfur content of more than 15% to prepare a solution having a gold:sulfur ratio of 1:0.08-0.20, stirring the solution at a temperature of 70-90° C. for reaction for 4-8 hours, washing the crystals with isopropyl alcohol after the reaction, and distilling and drying the solution under reduced pressure to 0.5-0.8 atmospheres for 0.5-1.5 hours to prepare the metal resinate.

[0078] In some embodiments, the organometallic polymer is a coordination polymer formed by the complexation of a homopolymer or copolymer with a metal. The homopolymer is typically poly(2-methyl-2-thiopyranylmethyl acrylate) formed by homopolymerization of 2-methyl-2-thiopyranylmethyl acrylate as a monomer. As a non-limiting example, the preparation method of the organometallic polymer using 2-methyl-2-thiopyranylmethyl acrylate as a monomer is as follows: ammonium tetrachloroaurate is dissolved in tetrahydrofuran, and a tetrahydrofuran solution of poly(2-methyl-2-thiopyranylmethyl acrylate) is added dropwise. After the reaction is completed, the reaction solution is poured into ethanol, and the precipitated colloid is washed three times with hot water and ethanol in sequence to obtain a brown powder, which is then filtered and dried to obtain the organometallic polymer.

[0079] Furthermore, the present application may also use a copolymer of 2-methyl-2-thiopyranylmethyl acrylate and other monomers as the polymer backbone of the organic gold polymer. As an example, other monomers may be selected from one or more of methyl methacrylate, tert-butyl methacrylate, vinyl acetate, styrene, hydroxyethyl methacrylate, acrylamide, and diphenyl sulfoxide as needed.

[0080] In some embodiments, the organic solvent is one or more of terpineol, butyl acetate, ethylene glycol monobutyl ether, butyl carbitol acetate, and dibutyl phthalate.

[0081] In some embodiments, the thixotropic agent is selected from one or more of polyamide wax, polyurea, magnesium silicate, and hydrogenated castor oil.

[0082] In some embodiments, the thickener is selected from one or more of ethyl cellulose, dibutyl phthalate, dioctyl phthalate, and triethanolamine.

[0083] In some embodiments, the dispersant is selected from one or more of polyvinyl pyrrolidone, hexadecyltrimethylammonium bromide, sodium citrate decahydrate, sodium dodecylbenzenesulfonate, Tween 20, and Span 80.

[0084] By adding a thickener, the viscosity of the organic metal conductor paste can be adjusted to make it suitable for subsequent printing of electrode patterns. For example, the viscosity of the organic metal conductor paste can be between 50,000 cP and 100,000 cP (viscosity testing conditions, such as XDV2THA #6, 50 rpm, and 25°C), making it suitable for printing electrode patterns on ceramic materials.

[0085] In some embodiments, the area of the first measuring electrode central portion 3 - 1 is smaller than the area of the second measuring electrode central portion 4 - 1 . For example, the ratio of the area of the first measuring electrode central portion to the area of the second measuring electrode central portion is 0.34-0.42:1. Thus, the area of the first measuring electrode central portion 3 - 1 is reduced by at least 20% compared to the area of the second measuring electrode central portion 4 - 1.

[0086] The internal effective electrode area of the first electrode 3 in the present application (i.e., the center portion 3-1 of the first measuring electrode) is significantly reduced in design. According to Formula 1, when the output capacitance value is the same, reducing the effective facing area can reduce the variation range of the gap value to improve the sensitivity of the core during operation, and can reduce the thickness of the gap isolation member 5 to reduce the deflection range of the core film, thereby increasing the product life.

[0087]

[0088] Therefore, as an example, in this application, the gap spacer acts as a sealing glass glaze between the ceramic substrate and the deformable diaphragm, and its thickness is between 10 μm and 20 μm. As can be seen from the above description, by reducing the thickness of the gap spacer 5, the core film deflection amplitude can be reduced, thereby extending the product life.

[0089] II. Preparation Method of Capacitive Pressure Sensor Core

[0090] The second aspect of the present application provides a method for preparing a capacitive pressure sensor core, such as Figure 6 As shown, the method includes:

[0091] Providing a ceramic substrate and a deformable diaphragm (step S100);

[0092] Preparing an organic metal conductor paste (step S200);

[0093] Printing, coating, or depositing an organic metal conductor paste on the ceramic substrate and the deformable membrane according to the patterns of the first electrode and the second electrode, respectively, to prepare a first electrode precursor and a second electrode precursor (step S300);

[0094] performing reduction sintering on the first electrode precursor and the second electrode precursor (step S400); and

[0095] The reduction-sintered ceramic substrate and the deformable diaphragm are bonded together in a compression manner (step S500 ).

[0096] In some embodiments, step S200 includes stirring 5% to 30% of an organometallic polymer, 10% to 40% of an organic solvent, 10% to 30% of a thixotropic agent, 10% to 30% of a thickener, and 5% to 10% of a dispersant by weight at a temperature of 50° C. to 70° C., and then cooling to room temperature to obtain an organometallic conductor slurry.

[0097] In some embodiments, the patterns of the first electrode and the second electrode in step S300 are similar to the first electrode 3 and the second electrode 4 described above. Preferably, in the present application, the organic metal conductor slurry can be printed, coated, or deposited on the ceramic substrate and the deformable diaphragm according to the patterns of the first electrode and the second electrode, thereby preparing the first electrode precursor and the second electrode precursor. Typically, step S300 may include placing the ceramic substrate and the deformable diaphragm in a designed metal mold, and using a screen printer to print the encapsulation slurry through the designed printing pattern on one side of the ceramic substrate and the deformable diaphragm where the electrode pattern is set, and the number of printing times is 3-6. As an example, the encapsulation slurry in the present application can be, for example, a glass slurry, so that after sealing and sintering, a glass glaze covering the electrode is formed.

[0098] In some embodiments, the printed first electrode precursor and the second electrode precursor are subjected to reduction sintering in step S400. The reduction sintering can be performed in a muffle furnace at a temperature of 800°C to 1000°C for 5 to 15 minutes at a heating rate between 3°C / min and 7°C / min to obtain smooth and dense conductive metal electrodes.

[0099] In some embodiments, a profilometer is optionally used to measure surface roughness and electrode thickness.

[0100] In some embodiments, step S500 may specifically involve face-to-face sealing of the reduction-sintered ceramic substrate and the deformable diaphragm. Specifically, step S500 may include: after reduction-sintering the first electrode precursor and the second electrode precursor, placing the reduction-sintered ceramic substrate in a metal mold, printing a packaging slurry onto the ceramic substrate with the first electrode pattern using a designed printing pattern, and then performing sealing sintering (step S510); and injecting epoxy silver paste into the through-holes on the top surface of the ceramic substrate and inserting metal pins, followed by curing (step S520).

[0101] Optionally, the curing treatment in step S520 is performed at a temperature of 150° C. to 300° C. for 5 minutes to 15 minutes.

[0102] By way of example and not limitation, the present invention provides a method for preparing a capacitive pressure sensor core, comprising: screen-printing an organic gold paste on a ceramic substrate and a deformable diaphragm, heating the ceramic substrate and the deformable diaphragm at a temperature of 700°C to 850°C at a temperature rise rate of 5°C / min-10°C / min for reduction sintering to form a first electrode and a second electrode, wherein the thickness of the first electrode and the second electrode is controlled to be 0.5 μm to 2 μm, and wherein the effective facing area of the first electrode is reduced by 25% relative to the prior art. Subsequently, screen-printing a packaging paste (e.g., a glass paste) on the ceramic substrate with the first electrode, with a thickness controlled to be 10 μm to 20 μm, drying the ceramic substrate with the first electrode, the second electrode and the packaging paste at 80°C to 100°C for 5 to 10 minutes, and sealing and sintering the ceramic substrate and the deformable diaphragm together at a temperature of 700°C to 850°C at a temperature rise rate of 5°C / min to 10°C / min, thereby forming a capacitive performance transducer. Subsequently, epoxy silver paste is injected into the through-holes in the ceramic substrate and metal pins are inserted, and the resultant is cured at 200° C. for 5 to 10 minutes to obtain a capacitive pressure sensor core.

[0103] III. Capacitive pressure sensor

[0104] The third aspect of the present application provides a capacitive pressure sensor, comprising: a capacitive pressure sensor core as described above, or a capacitive pressure sensor core prepared according to the method described above; and an external circuit, which is connected to the capacitive pressure sensor core through a metal pin.

[0105] The capacitive pressure sensor of this application utilizes a non-closed-loop, point-terminated shielding design between the first and second electrodes to connect metal pins, thereby achieving electrical conduction with the external circuit. Compared to existing shielding rings, this point-terminated shielding design excels in reducing the difficulty of CCD recognition during screen printing, improving positioning accuracy, and ultimately boosting screen printing yield, without compromising shielding performance.

[0106] In order to make the embodiments of the present invention easier to understand, the present application will be described in detail below with reference to examples. These examples are only for illustration and are not intended to limit the scope of application of the present application.

[0107] Unless otherwise specified, the operations and processing methods involved in this application are conventional methods in the art.

[0108] Unless otherwise specified, the instruments used in this application are conventional instruments in this field.

[0109] The chemicals involved in the specific embodiments of this application are not subjected to secondary purification. Among them, the organic gold polymer is a coordination polymer obtained by polymerizing (2-methyl-2-thiopyranylmethyl acrylate) purchased from Maclean and complexing with chloroauric acid.

[0110] The specific testing methods in this application are as follows:

[0111] The initial capacitance of the core was tested using an LCR meter purchased from Avitek to obtain the corresponding test results.

[0112] The microscopic morphology of the prepared capacitive pressure sensor core was observed and analyzed using a scanning electron microscope purchased from Zeiss.

[0113] The surface roughness and thickness of the electrode after reduction sintering are tested using a profilometer to obtain corresponding test results.

[0114] The surface roughness was tested according to the method described in the national standard GB / T 1031-2009;

[0115] The initial capacitance value is tested according to the method described in GB / T 15478-2015;

[0116] The electrode pattern screen printing yield is evaluated based on the screen printing accuracy range;

[0117] The change of core capacitance with pressure is tested according to the method described in GB / T 15478-2015.

[0118] Example 1

[0119] 25% organic gold polymer (McLean), 30% terpineol (McLean), 10% polyamide wax (Aladdin), 25% ethyl cellulose (Aladdin), and 10% polyvinyl pyrrolidone (Aladdin) were mixed and uniformly stirred at 60°C. After cooling, an organic gold conductive paste was obtained. The organic gold conductive paste was then screen-printed onto a ceramic substrate and a deformable diaphragm to form the first and second electrodes. The screen-printed sample was then heated to 850°C at a rate of 5°C / min and reduction-sintered for 5 minutes to produce smooth and dense gold electrodes. A sealing glass glaze was then screen-printed onto the ceramic substrate and dried at 100°C for 10 minutes to seal and sinter. Subsequently, epoxy silver paste was injected into the through-holes of the ceramic substrate and metal pins were inserted. The sample was cured at 200°C for 5 minutes to form the capacitive pressure sensor core.

[0120] Example 2

[0121] 25% organic gold polymer, 30% terpineol, 15% polyamide wax, 20% ethyl cellulose, and 10% polyvinyl pyrrolidone were mixed and uniformly stirred at 60°C. After cooling, an organic gold conductive paste was obtained. The organic gold conductive paste was then screen-printed onto a ceramic substrate and a deformable diaphragm to form the first and second electrodes. The screen-printed sample was then heated to 850°C at a rate of 10°C / min and subjected to reduction sintering for 5 minutes to produce smooth and dense gold electrodes. A sealing glass glaze was then screen-printed onto the ceramic substrate and dried at 100°C for 10 minutes to seal and sinter. Subsequently, epoxy silver paste was injected into the through-holes of the ceramic substrate and metal pins were inserted. The sample was cured at 200°C for 5 minutes to form the capacitive pressure sensor core.

[0122] Example 3

[0123] 28% organic gold polymer, 30% terpineol, 14% polyamide wax, 20% ethyl cellulose, and 8% polyvinyl pyrrolidone were mixed and uniformly stirred at 60°C. After cooling, an organic gold conductive paste was obtained. This paste was then screen-printed onto a ceramic substrate and a deformable diaphragm to form the first and second electrodes. The screen-printed sample was then heated to 850°C at a rate of 10°C / min and reduction-sintered for 10 minutes to produce smooth and dense gold electrodes. A sealing glass glaze was then screen-printed onto the ceramic substrate and dried at 100°C for 10 minutes to seal and sinter the sample. Subsequently, epoxy silver paste was injected into the through-holes of the ceramic substrate and metal pins were inserted. The sample was cured at 200°C for 5 minutes to form the capacitive pressure sensor core.

[0124] Example 4

[0125] 28% organic gold polymer, 30% terpineol, 15% polyamide wax, 20% ethyl cellulose, and 7% polyvinyl pyrrolidone were mixed and uniformly stirred at 80°C. After cooling, an organic gold conductive paste was obtained. This paste was then screen-printed onto a ceramic substrate and a deformable diaphragm to form the first and second electrodes. The screen-printed sample was then heated to 800°C at a rate of 10°C / min and subjected to reduction sintering for 5 minutes to produce smooth and dense gold electrodes. A sealing glass glaze was then screen-printed onto the ceramic substrate and dried at 100°C for 10 minutes to seal and sinter the sample. Subsequently, epoxy silver paste was injected into the through-holes of the ceramic substrate and metal pins were inserted. The sample was cured at 200°C for 5 minutes to form the capacitive pressure sensor core.

[0126] Example 5

[0127] 30% organic gold polymer, 30% terpineol, 10% polyamide wax, 20% ethyl cellulose, and 10% polyvinyl pyrrolidone were mixed and uniformly stirred at 80°C. After cooling, an organic gold conductive paste was obtained. The organic gold conductive paste was then screen-printed onto a ceramic substrate and a deformable diaphragm to form the first and second electrodes. The screen-printed sample was then heated to 800°C at a rate of 10°C / min and reduction-sintered for 10 minutes to produce smooth and dense gold electrodes. A sealing glass glaze was then screen-printed onto the ceramic substrate and dried at 100°C for 10 minutes to seal and sinter. Subsequently, epoxy silver paste was injected into the through-holes of the ceramic substrate and metal pins were inserted. The sample was cured at 200°C for 5 minutes to form the capacitive pressure sensor core.

[0128] Example 6

[0129] 30% organic gold polymer, 30% terpineol, 15% polyamide wax, 15% ethyl cellulose, and 15% polyvinyl pyrrolidone were mixed and uniformly stirred at 60°C. After cooling, an organic gold conductive paste was obtained. This paste was then screen-printed onto a ceramic substrate and a deformable diaphragm to form the first and second electrodes. The screen-printed sample was then heated to 850°C at a rate of 5°C / min and reduction-sintered for 5 minutes to produce smooth and dense gold electrodes. A sealing glass glaze was then screen-printed onto the ceramic substrate and dried at 100°C for 10 minutes to seal and sinter. Subsequently, epoxy silver paste was injected into the through-holes of the ceramic substrate and metal pins were inserted. The paste was then cured at 200°C for 5 minutes to form the capacitive pressure sensor core.

[0130] Comparative Example

[0131] Gold paste prepared from pure gold powder was screen-printed onto a ceramic substrate and a deformable diaphragm to form a control electrode. The printed sample was reduction-sintered at 850°C for 10 minutes to produce a smooth, dense gold electrode. Subsequently, a sealing glass glaze was screen-printed onto the ceramic substrate, dried at 100°C for 10 minutes, and sintered to seal the surface. Epoxy silver paste was then injected into the through-holes of the ceramic substrate, and metal pins were inserted. The sample was cured at 200°C for 5 minutes to form the capacitive pressure sensor core.

[0132] Table 1 shows a comparison of the surface roughness of electrodes of Examples 1 to 6 of the present application and the comparative example.

[0133] Table 1: Comparison of electrode surface roughness

[0134]

[0135] As can be seen in Table 1, the organic gold conductor paste of this application is a uniform, non-suspension, single-phase organic gold paste prepared using chloroauric acid and thioether. The gold element chemically bonds with the other elements in the paste, resulting in a uniform dispersion of the entire system. This allows for smooth and continuous coating on the ceramic during the screen printing process. Furthermore, after high-temperature reduction sintering, the Au element transforms from Au ions to elemental gold, further strengthening the bond between the prepared gold electrode and the ceramic. The electrode prepared using this organic gold paste has a dense, thin film and a smooth surface.

[0136] Table 2 further shows a comparison of the electrode pattern screen printing yields of Examples 1 to 6 of the present application and the comparative example.

[0137] Table 2: Comparison of screen printing yield of electrode patterns in Examples and Comparative Examples

[0138] Electrode screen printing yield Example 1 97.85％ Example 2 95.90％ Example 3 99.10％ Example 4 98.50％ Example 5 95.23％ Example 6 98.30％ Comparative Example 87.25％

[0139] As can be seen from Table 2, the organic gold conductor paste of the present application is a uniform non-suspension single-phase organic gold paste prepared from chloroauric acid and sulfide. By combining the electrode pattern of the present application (i.e., a parasitic capacitance shielding design with a non-closed-loop point-shaped ending), the difficulty of CCD recognition in the silk screen printing process is reduced and the positioning accuracy is improved without affecting the shielding function, thereby improving the silk screen printing yield.

[0140] Table 3 shows a comparison of the stability of the initial capacitance values of Examples 1 to 6 of the present application and the comparative example.

[0141] Table 3: Comparison of initial capacitance stability

[0142] Initial capacitance value pF Example 1 23.12 Example 2 21.45 Example 3 25.34 Example 4 20.50 Example 5 21.91 Example 6 25.60 Comparative Example 27.91

[0143] As can be seen from Table 3, the initial capacitance value of the capacitive pressure sensor core of the present application is more stable. By using the organic metal conductor paste, electrode pattern (i.e., parasitic capacitance shielding design with a non-closed-loop point-shaped ending) and reduced internal effective electrode area design of the first electrode of the present application, the initial capacitance of the capacitive pressure sensor core of the present application is more stable, the core is more sensitive during operation, effectively reducing the cracking of the electrode due to deflection during the operation of the core, and the output of the capacitance signal is more stable, which significantly improves the reliability and stability of the product.

[0144] Furthermore, Figure 7A A scanning electron microscope image of the interface between the electrode and the ceramic substrate in the capacitive pressure sensor core manufactured by the comparative example is shown, and Figure 7B The scanning electron microscope image of the interface between the electrode and the ceramic substrate in the capacitive pressure sensor core manufactured by Example 1 is shown. Figure 7A and Figure 7B It can be seen that the organic gold conductor slurry of the present application is a uniform non-suspension single-phase organic gold slurry prepared by chloroauric acid and sulfide, wherein the gold element is combined with other elements in the slurry in the form of chemical bonds, and the entire system is evenly dispersed. During the silk-screen printing process, it can be smoothly and continuously covered on the ceramic, and after high-temperature reduction sintering, the Au element is converted from the state of Au ions to gold elements, which makes the prepared gold electrode more firmly bonded to the ceramic. The electrode prepared by the organic gold slurry has a dense film, a thin film and a smooth surface.

[0145] also, Figure 8 The graph showing the capacitance value of the capacitive pressure sensor core manufactured by Examples 1 and 2 as a function of pressure is shown. Figure 8It can be seen that the capacitance value of the capacitive pressure sensor core of the present application increases linearly with the increase of pressure value, which indicates that the capacitive pressure sensor core of the present application has high sensitivity and the parasitic capacitance has little influence on the capacitive pressure sensor core of the present application. It can be seen that the non-closed-loop point-shaped ending shielding electrode of the present application can effectively shield the influence of parasitic capacitance on the capacitive pressure sensor core.

[0146] Although this specification sheet includes many specific details, these details should not be interpreted as limiting the scope of what may be described, but rather as a description of a specific embodiment of the subject matter. Certain features described in the context of different embodiments in this specification sheet may also be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented separately in multiple embodiments or in any suitable sub-combination. In addition, although a feature may be described above as working in certain combinations and even initially described as such, in some cases, one or more features from the described combination may be removed from the combination, and the described combination may be for a variation of a sub-combination or sub-combination.

[0147] The subject matter of this specification has been described in particular aspects, but other aspects may be implemented and are within the scope of the following claims. For example, although the operations are depicted in a particular order in the drawings, this should not be understood as requiring that the operations be performed in the particular order shown or in a continuous order, or that all of the operations shown be performed to achieve the desired result. The actions described in the claims can be performed in a different order and still achieve the desired result. As an example, the processes depicted in the drawings do not necessarily require the particular order shown or the continuous order to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of the various system components in the various aspects described above should be understood as requiring such separation in all aspects, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0148] The invention title, background technology, description of the figures, abstract and drawings are incorporated herein into this disclosure and are provided as illustrative examples of the disclosure rather than as limiting descriptions. It is submitted with the understanding that they will not be used to limit the scope or meaning of the claims. In addition, it can be seen in the detailed description that the description provides illustrative examples and different features are combined together in different embodiments to simplify the disclosure. The method of the present disclosure should not be interpreted as reflecting the following intention: the subject matter described requires more features than the features expressly recited in each claim. Rather, as reflected in the claims, the inventive subject matter lies in less than all the features of a single disclosed configuration or operation. The claims are incorporated herein into the detailed description, with each claim independently serving as the subject matter of a separate description.

[0149] The claims are not intended to be limited to the aspects described herein, but should be accorded the full scope consistent with the language of the claims and encompassing all legal equivalents. Nevertheless, no claim is intended to encompass subject matter that would not satisfy the requirements of applicable patent law, nor should they be construed in such a manner.

Claims

1. A capacitive pressure sensor core, characterized in that: include: Deformable diaphragm; a ceramic substrate, wherein a cavity is formed between a central region of a top surface of the deformable diaphragm and a central region of a bottom surface of the ceramic substrate, and the top surface of the ceramic substrate has a through hole for inserting a metal lead; as well as a capacitive performance transducer for detecting pressure-dependent deformation of the deformable diaphragm and comprising: a first electrode formed on a central area of a bottom surface of the ceramic substrate corresponding to the cavity and comprising a first measuring electrode portion and a first capacitive shielding electrode portion; a second electrode, the second electrode facing the first electrode and formed on a top surface of the deformable diaphragm corresponding to the cavity, and comprising a second measuring electrode portion and a second capacitive shielding electrode portion; and a gap spacer, the gap spacer being disposed between the first electrode and the second electrode; The first measuring electrode portion includes a first measuring electrode central portion, and the second measuring electrode portion includes a second measuring electrode central portion, and an area of the first measuring electrode central portion is smaller than an area of the second measuring electrode central portion; preferably, a ratio of an area of the first measuring electrode central portion to an area of the second measuring electrode central portion is 0.34-0.42:1; The first measuring electrode portion, the first capacitive shielding electrode portion, the second measuring electrode portion, and the second capacitive shielding electrode portion are formed by reduction sintering of an organic metal conductor paste.

2. The capacitive pressure sensor core according to claim 1, characterized in that: The first capacitive shielding electrode portion includes a first capacitive shielding electrode annular portion, a first capacitive shielding electrode extension portion, and a first capacitive shielding electrode dot portion, wherein the first capacitive shielding electrode annular portion is annular with an opening and surrounds the outer periphery of the central portion of the first measuring electrode, the first capacitive shielding electrode extension portion extends outward from both ends of the opening, and the first capacitive shielding electrode dot portion is connected to the first capacitive shielding electrode extension portion and is electrically connected to the metal lead; and The second capacitive shielding electrode portion includes a second capacitive shielding electrode annular portion, a second capacitive shielding electrode extension portion, and a second capacitive shielding electrode point portion. The second capacitive shielding electrode annular portion is a ring with an opening and surrounds the outer circumference of the central portion of the second measuring electrode. The second capacitive shielding electrode extension portion extends outward from both ends of the opening. The second capacitive shielding electrode point portion is connected to the second capacitive shielding electrode extension portion and is electrically connected to the metal lead.

3. The capacitive pressure sensor core according to claim 1, characterized in that: The organic metal conductor paste includes at least two of an organic metal polymer, an organic solvent, a thixotropic agent, a thickener, and a dispersant; and / or, the organic metal conductor paste contains, by weight percentage, 5% to 30% of the organic metal polymer, 10% to 40% of the organic solvent, 10% to 30% of the thixotropic agent, 10% to 30% of the thickener, and 5% to 10% of the dispersant.

4. The capacitive pressure sensor core according to claim 3, characterized in that: The organometallic polymer is an organic gold polymer, an organic silver polymer, an organic copper polymer, and / or an organic platinum polymer; and / or the organic solvent is one or more of terpineol, butyl acetate, ethylene glycol monobutyl ether, butyl carbitol acetate, and dibutyl phthalate; and / or the thixotropic agent is one or more of polyamide wax, polyurea, magnesium silicate, and hydrogenated castor oil; and / or the thickener is one or more of ethyl cellulose, dibutyl phthalate, dioctyl phthalate, and triethanolamine; and / or the dispersant is one or more of polyvinyl pyrrolidone, hexadecyltrimethylammonium bromide, sodium citrate decahydrate, sodium dodecylbenzenesulfonate, Tween 20, and Span 80.

5. The capacitive pressure sensor core according to claim 3, characterized in that: The organometallic polymer is a metal resin acid, which is prepared by reacting a metal chloride with any one of a thiol and a sulfurized balsam, wherein the thiol is selected from one or more of tert-dodecyl mercaptan, n-dodecyl mercaptan, p-tert-butylbenzyl mercaptan, and decanedithiol, and the sulfurized balsam is selected from one or more of sulfurized turpentine, sulfurized copiaba balsam, and sulfurized terpenes; and / or the organometallic polymer is a coordination polymer formed by complexing a homopolymer or copolymer with a metal, wherein the homopolymer is formed by homopolymerizing 2-methyl-2-acrylic acid thiopyranyl methyl ester as a monomer, and the copolymer is formed by copolymerizing 2-methyl-2-acrylic acid thiopyranyl methyl ester and a monomer mixture selected from one or more of the following: methyl methacrylate, tert-butyl methacrylate, vinyl acetate, styrene, hydroxyethyl methacrylate, acrylamide, and diphenyl sulfoxide.

6. The capacitive pressure sensor core according to claim 1, characterized in that: The thickness of the gap spacer is between 10 μm and 20 μm.

7. A method for preparing a capacitive pressure sensor core according to any one of claims 1 to 6, characterized in that: The method comprises: Provide ceramic substrate and deformable diaphragm; preparing an organic metal conductor slurry; Printing, coating, or depositing the organic metal conductor paste on the ceramic substrate and the deformable membrane according to the patterns of the first electrode and the second electrode, respectively, to prepare a first electrode precursor and a second electrode precursor; performing reduction sintering on the first electrode precursor and the second electrode precursor; and The reduction-sintered ceramic substrate and the deformable diaphragm are joined in a compression-tight manner.

8. The method according to claim 7, characterized in that The step of press-bonding the reduction-sintered ceramic substrate and the deformable diaphragm comprises: After reduction sintering the first electrode precursor and the second electrode precursor, placing the reduction sintered ceramic substrate in a metal mold, printing a packaging slurry on the ceramic substrate with the first electrode pattern through a designed printing pattern, and then sealing and sintering to form a gap spacer; and Epoxy silver paste is injected into the through holes on the top surface of the ceramic substrate, metal pins are inserted, and then a curing process is performed.

9. The method according to claim 8, characterized in that The reduction sintering is carried out at a temperature of 700°C to 1000°C, the reduction sintering time is 5 minutes to 15 minutes, and the heating rate is between 3°C / min and 10°C / min; and / or, the temperature of the curing treatment is 150°C to 300°C, and the treatment time is 5 minutes to 15 minutes.

10. A capacitive pressure sensor, characterized in that: include: A capacitive pressure sensor core according to any one of claims 1 to 6, or a capacitive pressure sensor core prepared by the method according to any one of claims 7 to 9; as well as An external circuit is connected to the capacitive pressure sensor core through a metal pin.

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