Pressure sensor, pressure sensing array and preparation method thereof

Abstract

The invention relates to a pressure sensor, a pressure sensing array and a preparation method thereof. The pressure sensor comprises a first substrate, the upper surface of which is provided with a first sensing electrode; the first pressure-sensitive layer is located on the surface of the first sensing electrode, and the first pressure-sensitive layer is a piezoresistive film with a microphase separation structure and a rough upper surface; the lower surface of the second substrate is provided with a second sensing electrode, and the second sensing electrode and the first sensing electrode are oppositely arranged; the second pressure-sensitive layer is located on the lower surface of the second sensing electrode, the second pressure-sensitive layer is a piezoresistive film with micro-phase separation and a rough lower surface, and the lower surface of the second pressure-sensitive layer is opposite to the upper surface of the first pressure-sensitive layer. The pressure sensor provided by the invention has higher sensitivity under high pressure and thin thickness.

Description

Technical Field

[0001] The present invention relates to the field of sensing technology, and in particular to a pressure sensor, a pressure sensing array and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of wearable products, flexible sensor components have become one of the hot topics explored by researchers. Among them, flexible pressure sensors have received particular attention and have very broad market prospects in the fields of artificial electronic skin, flexible touch screens, intelligent robots, and medical health.

[0003] At present, the research on flexible pressure sensors can be based on a variety of working principles, mainly including: capacitive, resistive, piezoelectric and thin film transistor. Among them, resistive pressure sensors are widely used due to their simple structure and lack of external electromagnetic interference. However, after the thickness of the sensitive film of the resistive pressure sensor is reduced, there is a problem of decreased sensitivity due to the increase in the sensing range.

[0004] Therefore, how to reduce the thickness of the resistive pressure sensor while improving the sensitivity and sensing range of the resistive pressure sensor is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The present invention provides a pressure sensor, a pressure sensing array and a preparation method thereof, which are used to solve the problem that the existing ultra-thin pressure sensor cannot have both high sensitivity and a large sensing range, so as to improve the performance of the pressure sensor and expand the application field of the pressure sensor.

[0006] According to some embodiments, the present invention provides a pressure sensor, comprising:

[0007] A first substrate, comprising an upper surface and a lower surface that are oppositely distributed;

[0008] A first sensing electrode, located on the upper surface of the first substrate;

[0009] A first piezoresistive layer is located on a surface of the first sensing electrode facing away from the first substrate, the first piezoresistive layer being a first piezoresistive film layer having a microphase separation structure and a rough surface facing away from the first substrate;

[0010] A second substrate, comprising an upper surface and a lower surface that are oppositely distributed, wherein the lower surface of the second substrate is arranged toward the upper surface of the first substrate;

[0011] A second sensing electrode is located on the lower surface of the second substrate;

[0012] The second piezoresistive layer is located on the surface of the second sensing electrode facing away from the second substrate. The second piezoresistive layer is a second piezoresistive film layer with microphase separation and a rough surface facing away from the second substrate.

[0013] In some embodiments, the roughness of a surface of the first piezoresistive film layer facing away from the first substrate and the roughness of a surface of the second piezoresistive film layer facing away from the second substrate are both in a range of 100 nanometers to 50 micrometers.

[0014] In some embodiments, the material of the first piezoresistive film layer and the material of the second piezoresistive film layer are both block polymers doped with conductive nanomaterials or mixed materials of thermoplastic polymers and thermosetting polymers doped with conductive nanomaterials, the thermoplastic polymers include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide, polyformaldehyde, polycarbonate, polyphenylene ether, polysulfone, and the thermosetting polymer materials include phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, epoxy resin, unsaturated resin, polyurethane, and polyimide.

[0015] In some embodiments, the conductive nanomaterial is any one of nano-carbon powder, nano-graphite, carbon nanotube and nano-graphene, or a combination of two or more thereof, and the conductive nanomaterial has a diameter of 20 nanometers to 10 micrometers;

[0016] The conductive nanomaterials doped in the polymer include a variety of different diameters, and the maximum diameter of the doped conductive nanomaterials is less than 3 times the minimum diameter or the maximum diameter of the doped conductive nanomaterials is more than 5 times the minimum diameter.

[0017] In some embodiments, the doping concentration of the conductive nanomaterial in the polymer is 0.5% to 10%, and the doping concentrations of the conductive nanomaterial in the thermoplastic polymer and the thermosetting polymer are the same or different.

[0018] In some embodiments, the first piezoresistive film layer and the second piezoresistive film layer both include a leveling agent, a defoaming agent, a diluent, and a conductive nanomaterial dispersant.

[0019] In some embodiments, the materials of the first sensing electrode and the second sensing electrode are any one of conductive polymers, carbon-based conductors, metal oxides, metal nanowires, metal and metal oxide nanoparticles, and conductive pastes based on carbon-based conductors, metal nanowires, metal and metal oxide nanoparticles.

[0020] According to some other embodiments, the present invention further provides a pressure sensing array, comprising:

[0021] A plurality of pressure sensors as described in any one of the above items, wherein the plurality of pressure sensors are arranged in an array;

[0022] The first sensing electrodes in the plurality of pressure sensors arranged in the same row are electrically connected and collectively serve as row electrodes;

[0023] The second sensing electrodes in the plurality of pressure sensors arranged in the same column are electrically connected and collectively serve as column electrodes, and the column electrodes are arranged orthogonally to the row electrodes;

[0024] The pressure sensing array also includes an adhesive layer, which is sandwiched between the first substrate and the second substrate, and has a plurality of openings corresponding to the plurality of pressure sensors. The first pressure-sensitive layer and the second pressure-sensitive layer in each of the pressure sensors are located in the openings corresponding thereto, and the position of each of the openings is aligned with the first sensing electrode and the second sensing electrode in one of the pressure sensors.

[0025] According to some further embodiments, the present invention further provides a method for preparing the pressure sensing array as described above, comprising the following steps:

[0026] providing a first substrate and a second substrate;

[0027] forming the row electrodes on the upper surface of the first substrate, and forming the column electrodes on the lower surface of the second substrate;

[0028] forming a first pressure-sensitive layer covering the row electrodes, and forming a second pressure-sensitive layer covering the column electrodes, wherein the size of the first pressure-sensitive layer is the same as the size of the second pressure-sensitive layer;

[0029] forming an adhesive layer on the upper surface of the first substrate, wherein the adhesive layer has a plurality of openings exposing the first pressure-sensitive layer;

[0030] The second substrate is attached to the adhesive layer along a direction in which the second pressure-sensitive layer is aligned with the first pressure-sensitive layer, so that the row electrodes and the column electrodes are arranged orthogonally.

[0031] In some embodiments, the row electrodes, the column electrodes, the first pressure-sensitive layer and the second pressure-sensitive layer are all prepared by screen printing, scraping or spraying;

[0032] The adhesive layer is prepared by laser cutting a double-sided adhesive film, dispensing, screen printing, scraping or spraying.

[0033] The pressure sensor, pressure sensing array and preparation method thereof provided by the present invention use a first piezoresistive film layer with a microphase separation structure and a rough surface facing away from the first substrate as the first piezoresistive layer on the first sensing electrode, and use a second piezoresistive film layer with a microphase separation and a rough surface facing away from the second substrate as the second piezoresistive layer on the second sensing electrode. The contact area between the rough surface of the first piezoresistive layer and the rough surface of the second piezoresistive layer changes when subjected to external pressure. For example, the contact area between the first piezoresistive layer and the second piezoresistive layer increases under external pressure, thereby achieving the effect of increasing the resistance value of the sensor and reducing the power consumption of the sensor at the same time. In the present invention, the doping concentration of the conductive nanomaterial in the first piezoresistive layer and the second piezoresistive layer in the polymer is in the percolation region. Under the action of external pressure, the spacing between the conductive nanomaterials decreases, causing an increase in conductivity. Moreover, the material of the first pressure-sensitive layer and the material of the second pressure-sensitive layer are both a mixture of thermoplastic polymer and thermosetting polymer with certain compatibility or a block copolymer, and microphase separation occurs spontaneously during the thermal curing process. The surface microstructures of the pressure-sensitive film in the device are relatively arranged, and the area of ​​the microstructure interface increases under the action of external pressure, thereby improving the sensitivity of the pressure sensor. The pressure sensing array provided by the present invention has an adhesive layer, which can improve the electrical stability of the pressure sensing array under high pressure and lateral shear force. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic cross-sectional view of a pressure sensor in a specific embodiment of the present invention;

[0035] Figure 2 is a flow chart of a method for preparing a pressure sensing array in a specific embodiment of the present invention;

[0036] Figure 3 is a schematic diagram of a structure after row electrodes are formed on a first substrate in a specific embodiment of the present invention;

[0037] Figure 4 is a schematic diagram of a structure after a first pressure-sensitive layer is formed on a first substrate in a specific embodiment of the present invention;

[0038] Figure 5 is a schematic diagram of a structure after an adhesive layer is formed on a first substrate in a specific embodiment of the present invention;

[0039] Figure 6 is a schematic diagram of the structure after forming column electrodes and a second pressure-sensitive layer on a second substrate in a specific embodiment of the present invention;

[0040] Figure 7 It is a schematic diagram of the structure after the second pressure-sensitive layer is attached to the adhesive layer in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0041] The specific implementation methods of the pressure sensor, pressure sensing array and preparation method thereof provided by the present invention are described in detail below with reference to the accompanying drawings.

[0042] This specific embodiment provides a pressure sensor, Figure 1 FIG. 1 is a schematic cross-sectional view of a pressure sensor in a specific embodiment of the present invention. Figure 1 As shown, the pressure sensor comprises:

[0043] The first substrate 100 includes an upper surface and a lower surface that are oppositely distributed;

[0044] A first sensing electrode 101 is located on the upper surface of the first substrate 100;

[0045] A first piezoresistive layer 102 is located on a surface of the first sensing electrode 101 facing away from the first substrate 100 , and the first piezoresistive layer 102 is a first piezoresistive film layer having a microphase separation structure and a rough surface facing away from the first substrate 100 ;

[0046] The second substrate 200 comprises an upper surface and a lower surface which are arranged opposite to each other, and the lower surface of the second substrate 200 is arranged toward the upper surface of the first substrate 100;

[0047] A second sensing electrode 201 is located on the lower surface of the second substrate 200;

[0048] The second piezoresistive layer 202 is located on the surface of the second sensing electrode 201 away from the second substrate 200 . The second piezoresistive layer 202 is a second piezoresistive film layer with micro-phase separation and a rough surface away from the second substrate 200 .

[0049] Specifically, the first substrate 100 includes an upper surface and a lower surface that are relatively distributed, and the second substrate 200 also includes an upper surface and a lower surface that are relatively distributed. The second substrate 200 is located above the first substrate 100, and the lower surface of the second substrate 200 is opposite to the upper surface of the first substrate 100. The first sensing electrode 101 and the first pressure-sensitive layer 102 are sequentially stacked on the upper surface of the first substrate 100 along a direction perpendicular to the upper surface of the first substrate 100. The second sensing electrode 201 and the second pressure-sensitive layer 202 are sequentially stacked on the lower surface of the second substrate 200 along a direction perpendicular to the lower surface of the second substrate 200. The upper surface of the first substrate 100 is parallel to the lower surface of the second substrate 200. The first substrate 100 and the second substrate 200 are both used as the bearing substrate of the pressure sensor. In an example, the material of the first substrate 100 and the material of the second substrate 200 are both polyurethane, polyimide, polyethylene terephthalate plastic, polyethylene naphthalate, polydimethylsiloxane, polyurethane or platinum-catalyzed silica gel.

[0050] In this specific embodiment, the first piezoresistive layer 102 is a first piezoresistive film layer having a microphase separation structure and a rough surface facing away from the first substrate 100 (i.e., the upper surface of the first piezoresistive layer 102); the second piezoresistive layer 202 is a second piezoresistive film layer having a microphase separation and a rough surface facing away from the second substrate 200 (i.e., the lower surface of the second piezoresistive layer 202); and the rough surface of the first piezoresistive film layer is arranged opposite to the rough surface of the second piezoresistive film layer, that is, the surface of the first piezoresistive layer 102 facing the second piezoresistive layer 202 and the surface of the second piezoresistive layer 202 facing the first piezoresistive layer 102 both have microstructures. Under the action of external pressure, the contact area between the microstructure on the surface of the first piezoresistive layer 102 and the microstructure on the surface of the second piezoresistive layer 202 changes, for example, the contact area increases, so that the pressure sensor is not limited by the thickness of the first piezoresistive layer 102 and the thickness of the second piezoresistive layer 202, and can thus have both high sensitivity and a large sensing range, thereby improving the performance of the pressure sensor.

[0051] In some embodiments, the roughness of the surface of the first piezoresistive film layer away from the first substrate 100 and the roughness of the surface of the second piezoresistive film layer away from the second substrate 200 are both 100 nanometers to 50 micrometers. In one example, the height difference between the lowest valley and the highest peak on the surface of the first piezoresistive film layer away from the first substrate 100 is within 100 nanometers to 50 micrometers, and the height difference between the lowest valley and the highest peak on the surface of the second piezoresistive film layer away from the second substrate 200 is also within 100 nanometers to 50 micrometers.

[0052] In some embodiments, the material of the first piezoresistive film layer and the material of the second piezoresistive film layer are both block polymers doped with conductive nanomaterials or mixed materials of thermoplastic polymers and thermosetting polymers doped with conductive nanomaterials, the thermoplastic polymers include polyethylene, polypropylene, vinyl chloride, polystyrene, polyamide, polyformaldehyde, polycarbonate, polyphenylene ether, polysulfone, and the thermosetting polymer materials include phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, epoxy resin, unsaturated resin, polyurethane, and polyimide. In one example, the thermoplastic polymer and the thermosetting polymer are compatible polymers but have different glass transition temperatures, and the thermosetting polymer is a single-component thermal cross-linking material or a polymer with a cross-linking agent added.

[0053] In some embodiments, the doping concentration of the conductive nanomaterial in the polymer is 0.5% to 10%, and the doping concentrations of the conductive nanomaterial in the thermoplastic polymer and the thermosetting polymer are the same or different.

[0054] In one example, the doping concentration of the conductive nanomaterial in the block polymer is 0.5% to 10%; or, the doping concentration of the conductive nanomaterial in the mixed material of thermoplastic polymer and thermosetting polymer is 0.5% to 10%. In the pressure sensor provided in this specific embodiment, the doping concentration of the conductive nanomaterial in the polymer (such as block polymer or mixed material of thermoplastic polymer and thermosetting polymer) in the first pressure-sensitive layer 102 and the second pressure-sensitive layer 202 is located in the percolation zone. Under the action of external pressure, the spacing of the conductive nanomaterials decreases, causing the conductivity to increase, so that the sensitivity of the pressure sensor is further increased. At the same time, the microstructures on the surfaces of the first pressure-sensitive layer 102 and the second pressure-sensitive layer 202 are arranged relative to each other, and the area of ​​the microstructure interface increases under the action of external pressure, thereby improving the sensitivity of the pressure sensor.

[0055] In some embodiments, the conductive nanomaterial is any one of nano-carbon powder, nano-graphite, carbon nanotube and nano-graphene, or a combination of two or more thereof, and the conductive nanomaterial has a diameter of 20 nanometers to 10 micrometers;

[0056] The conductive nanomaterials doped in the polymer include a variety of different diameters, and the maximum diameter of the doped conductive nanomaterials is less than 3 times the minimum diameter or the maximum diameter of the doped conductive nanomaterials is more than 5 times the minimum diameter.

[0057] In some embodiments, the first piezoresistive film layer and the second piezoresistive film layer both include a leveling agent, a defoaming agent, a diluent, and a conductive nanomaterial dispersant.

[0058] In some embodiments, the materials of the first sensing electrode 101 and the second sensing electrode 201 are any one of conductive polymers, carbon-based conductors, metal oxides, metal nanowires, metal and metal oxide nanoparticles, and conductive pastes based on carbon-based conductors, metal nanowires, metal and metal oxide nanoparticles.

[0059] Specifically, the conductive polymer is poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid), polystyrene sulfonic acid, polyaniline, polythiophene or polypyrrole with an acidic or neutral pH value. The carbon-based conductive material is single-layer or multi-layer graphene, graphite, carbon black, single-wall or multi-wall carbon nanotube. The metal is gold, silver, copper, aluminum or nickel. The metal oxide is indium tin oxide or fluorine-doped tin oxide.

[0060] In addition, this specific embodiment also provides a pressure sensor array. The pressure sensor array includes:

[0061] A plurality of pressure sensors as described in any one of the above items (see Figure 1 ), and a plurality of the pressure sensors are arranged in an array;

[0062] The first sensing electrodes 101 in the plurality of pressure sensors arranged in the same row are electrically connected and collectively serve as row electrodes;

[0063] The second sensing electrodes 201 in the plurality of pressure sensors arranged in the same column are electrically connected and collectively serve as column electrodes, and the column electrodes are arranged orthogonally to the row electrodes;

[0064] The pressure sensing array also includes an adhesive layer, which is sandwiched between the first substrate 100 and the second substrate 200, and has a plurality of openings corresponding to the plurality of pressure sensors. The first pressure-sensitive layer 102 and the second pressure-sensitive layer 202 in each of the pressure sensors are located in the corresponding openings, and the position of each of the openings is aligned with the first sensing electrode 101 and the second sensing electrode 201 in one of the pressure sensors.

[0065] In some embodiments, the Young's modulus of the first pressure-sensitive layer 102 is equal to the Young's modulus of the second pressure-sensitive layer 202, and the Young's modulus of the adhesive layer is less than or equal to the Young's modulus of the first pressure-sensitive layer 102;

[0066] The thickness of the adhesive layer is equal to the sum of the thickness of the first pressure-sensitive layer 102 and the second pressure-sensitive layer 202 .

[0067] This embodiment increases the range of the pressure sensor by changing the contact area of ​​the microstructure between the first high modulus pressure-sensitive layer 102 and the second pressure-sensitive layer 202. The pressure sensing array provided by this embodiment has an adhesive layer, which can improve the electrical stability of the pressure sensing array under high pressure and lateral shear force.

[0068] This specific embodiment also provides a method for preparing the pressure sensor array as described above. Figure 2 is a flow chart of a method for preparing a pressure sensing array in a specific embodiment of the present invention, Figure 3 is a schematic diagram of a structure after row electrodes are formed on a first substrate in a specific embodiment of the present invention, Figure 4 is a schematic diagram of a structure after a first pressure-sensitive layer is formed on a first substrate in a specific embodiment of the present invention, Figure 5 is a schematic diagram of a structure after forming an adhesive layer on a first substrate in a specific embodiment of the present invention, Figure 6 is a schematic diagram of the structure after forming column electrodes and a second pressure-sensitive layer on a second substrate in a specific embodiment of the present invention, Figure 7 Schematic diagram of the structure after the second pressure-sensitive layer is attached to the adhesive layer in a specific embodiment of the present invention. The structure of the pressure sensor in the pressure sensing array prepared in this specific embodiment is shown in FIG. Figure 1 .like Figure 1-Figure 7 As shown, the method for preparing the pressure sensing array comprises the following steps:

[0069] Step S21, providing a first substrate 100 and a second substrate 200;

[0070] Step S22, forming the row electrodes 300 on the upper surface of the first substrate 100, such as Figure 3 As shown, the column electrodes 500 are formed on the lower surface of the second substrate 200, as shown Figure 6 As shown;

[0071] Step S23, forming a first pressure-sensitive layer 102 covering the row electrode 300, such as Figure 4 As shown, a second pressure-sensitive layer 202 covering the column electrode 500 is formed, as shown Figure 6 As shown, the size of the first pressure-sensitive layer 102 is the same as the size of the second pressure-sensitive layer 202;

[0072] Step S24, forming an adhesive layer 400 on the upper surface of the first substrate 200, wherein the adhesive layer 400 has a plurality of openings 401 exposing the first pressure-sensitive layer 102, such as Figure 5 As shown;

[0073] Step S25, laminating the second substrate 200 on the adhesive layer 400 along the direction in which the second pressure-sensitive layer 202 is aligned with the first pressure-sensitive layer 102, so that the row electrodes 300 and the column electrodes 500 are arranged orthogonally, as shown in FIG. Figure 7 and Figure 1 As shown. Among them, Figure 7 The column electrodes 500 are not visible at the angle shown, so the positions of the column electrodes 500 on the second substrate 200 are indicated by dotted lines.

[0074] For example, the material of the first substrate 100 and the material of the second substrate 200 can both be polyurethane, polyimide, polyethylene terephthalate plastic, polyethylene naphthalate, polydimethylsiloxane (PDMS), polyurethane (PU) or platinum catalyzed silica gel (Ecoflex), etc., and the first substrate 100 and the second substrate 200 are both used as the bearing substrate of the pressure sensor. In this specific embodiment, the first substrate 100 and the second substrate 200 can be ultrasonically cleaned with ethanol solution, acetone solution and deionized water, and dried after cleaning, and the surfaces of the first substrate 100 and the second substrate 200 are treated with oxygen plasma or ultraviolet light / ozone.

[0075] In some embodiments, the row electrodes 300, the column electrodes 500, the first pressure-sensitive layer 102 and the second pressure-sensitive layer 202 are all prepared by screen printing, scraping or spraying;

[0076] The adhesive layer 400 is prepared by laser cutting a double-sided adhesive film, dispensing, screen printing, scraping or spraying.

[0077] For example, the row electrode 300 may be divided into a plurality of first sensing electrodes 101 arranged at intervals and a first conductive connection layer located between two adjacent first sensing electrodes 101 and electrically connecting the two adjacent first sensing electrodes 101. The column electrode 500 may be divided into a plurality of second sensing electrodes 201 arranged at intervals and a second conductive connection layer located between two adjacent second sensing electrodes 201 and electrically connecting the two adjacent second sensing electrodes 201. The material of the row electrode 300 and the material of the column electrode 500 may both be conductive polymers, carbon-based conductive materials, metal oxides, metal nanowires, metal and metal oxide nanoparticles, and conductive pastes based on carbon-based conductive materials, metal nanowires, metal and metal oxide nanoparticles. The conductive polymer may be poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid), polystyrene sulfonic acid, polyaniline, polythiophene or polypyrrole with acidic or neutral pH value, the carbon-based conductive material may be single-layer or multi-layer graphene, graphite, carbon black, single-wall or multi-wall carbon nanotube, etc., the metal may be gold, silver, copper, aluminum or nickel, and the metal oxide may be indium tin oxide or fluorine-doped tin oxide, etc. In this specific embodiment, the row electrode 300 and the column electrode 500 may be prepared by screen printing, spraying, dispensing, inkjet printing, sputtering and evaporation.

[0078] The material of the first pressure-sensitive layer 102 and the material of the second pressure-sensitive layer 103 are both block polymers doped with conductive nanomaterials or mixed materials of thermoplastic polymers and thermosetting polymers doped with conductive nanomaterials, and the doping concentration of the conductive nanomaterials in the polymer (such as the block polymer or the mixed material of thermoplastic polymers and thermosetting polymers) is in the percolation zone. Optionally, the doping concentration of the conductive nanomaterials is 0.5% to 10%. Optionally, the conductive nanomaterials are any one of nano-carbon powder, nano-graphite, carbon nanotubes and nano-graphene, or a combination of two or more. The size of the conductive nanomaterials is between 20 nanometers and 10 microns, and the conductive nanomaterials doped in the polymer are mixed with similar sizes within 3 times or with different sizes of 5 times or more. In this specific embodiment, the first pressure-sensitive layer 102 and the second pressure-sensitive layer 202 can be prepared by screen printing, scraping or spraying. Figure 4 and Figure 6As shown, multiple first pressure-sensitive layers 102 are arranged in an array above the first substrate 100, and multiple second pressure-sensitive layers 202 are arranged in an array above the second substrate 200, and the shape and size of the first pressure-sensitive layer 102 are equal to the shape and size of the second pressure-sensitive layer 202, the spacing widths between any adjacent first pressure-sensitive layers 102 are equal, the spacing widths between any adjacent second pressure-sensitive layers 202 are equal, and the spacing widths between any adjacent first pressure-sensitive layers 102 are equal to the spacing widths between any adjacent second pressure-sensitive layers 202, so that the multiple first pressure-sensitive layers 102 correspond one-to-one to the multiple second pressure-sensitive layers 202.

[0079] The adhesive layer 400 is used to bond the first substrate 100 and the second substrate 200. The Young's modulus of the adhesive layer 400 does not exceed the Young's modulus of the first pressure-sensitive layer 102 and the Young's modulus of the second pressure-sensitive layer 202. The adhesive layer 400 has hollows arranged in an array at the position of the row electrodes 300, that is, the adhesive layer 400 has openings 401 arranged in an array at the position of the row electrodes 300. The area of ​​each opening 401 is consistent with the area of ​​one of the pressure sensor devices, and the spacing between two adjacent rows of the openings 401 is consistent with the spacing between two adjacent rows of the row electrodes 300. For example, the area of ​​each opening 401 is consistent with the area of ​​the first pressure-sensitive layer 102 in one of the pressure sensors, and the spacing between two adjacent rows of the openings 401 is consistent with the spacing between two adjacent rows of the row electrodes 300. The material of the adhesive layer 400 can be a double-sided sticky elastic film tape, polydimethylsiloxane (PDMS) film, polyurethane (PU) film or platinum-catalyzed silicone (Ecoflex) film. The hollowing of the adhesive layer 400 can be formed by laser or tool cutting, or by dispensing, screen printing, scraping or spraying on the surface of the first substrate 100, and then formed by heating and curing.

[0080] The second substrate 200 is bonded to the surface of the adhesive layer 400 to form the pressure sensor array. The column electrodes 500 are orthogonal to the row electrodes 300, and the first pressure-sensitive layer 102 and the second pressure-sensitive layer 202 are both located in the opening 401 of the adhesive layer 400. In this specific embodiment, the electrical crosstalk between adjacent pressure sensors can be reduced by using the adhesive layer 400 to bond the first insulating layer 102 and the second insulating layer 202, and the electrical stability of the pressure sensor array under high pressure and lateral shear force can be improved.

[0081] The pressure sensor, pressure sensing array and preparation method thereof provided in this specific embodiment are as follows: a first piezoresistive film layer with a microphase separation structure and a rough surface facing away from the first substrate is used as the first pressure-sensitive layer on the first sensing electrode, and a second piezoresistive film layer with a microphase separation and a rough surface facing away from the second substrate is used as the second pressure-sensitive layer on the second sensing electrode. The contact area between the rough surface of the first pressure-sensitive layer and the rough surface of the second pressure-sensitive layer changes when subjected to external pressure. For example, the contact area between the first pressure-sensitive layer and the second pressure-sensitive layer increases under external pressure, thereby simultaneously achieving the effect of increasing the resistance value of the sensor and reducing the power consumption of the sensor, and the detection sensitivity of the pressure sensor is not limited by the thickness of the first pressure-sensitive layer and the second pressure-sensitive layer. In this specific embodiment, the doping concentration of the conductive nanomaterial in the first pressure-sensitive layer and the second pressure-sensitive layer in the polymer is in the percolation region. Under the action of external pressure, the spacing between the conductive nanomaterials decreases, causing an increase in conductivity. Moreover, the material of the first pressure-sensitive layer and the material of the second pressure-sensitive layer are both a mixture of thermoplastic polymer and thermosetting polymer with certain compatibility or a block copolymer, and microphase separation occurs spontaneously during the thermal curing process. The surface microstructures of the pressure-sensitive film in the device are relatively arranged, and the area of ​​the microstructure interface increases under the action of external pressure, thereby improving the sensitivity of the pressure sensor. The pressure sensing array provided in this specific embodiment has an adhesive layer, which can improve the electrical stability of the pressure sensing array under high pressure and lateral shear force.

[0082] The following are 6 examples of preparing the pressure sensing array.

[0083] Example 1

[0084] The pressure sensing array is prepared by the following specific steps:

[0085] (1) ultrasonically cleaning a first substrate and a second substrate both made of polyethylene terephthalate (PET) using an ethanol solution, an acetone solution, and deionized water, drying the substrate after cleaning, and treating the surfaces of the first substrate and the second substrate using oxygen plasma or ultraviolet light / ozone;

[0086] (2) preparing row electrodes and column electrodes on the upper surface of the first substrate and the lower surface of the second substrate respectively by screen printing;

[0087] (3) using a screen printing process to prepare a patterned pressure-sensitive layer on the surface of the row electrode and the column electrode to form the first pressure-sensitive layer and the second pressure-sensitive layer, wherein the material of the first pressure-sensitive layer and the material of the second pressure-sensitive layer are polyimide and polystyrene doped with carbon nanoparticles, and the doping concentration is 3%; the first pressure-sensitive layer, the second pressure-sensitive layer, the row electrode and the column electrode are aligned and overlapped;

[0088] (4) forming an array of hollow (i.e., the opening) patterns on the surface of the double-sided adhesive tape (i.e., the adhesive layer) by laser cutting, wherein the spacing of the hollow patterns is consistent with the spacing of the row / column electrodes; attaching the double-sided adhesive tape to the surface of the row / column electrodes, wherein the hollow positions of the double-sided adhesive tape overlap with the first pressure-sensitive layer and the second pressure-sensitive layer;

[0089] (5) The second substrate is bonded to the double-sided adhesive surface, and the second pressure-sensitive layer on the second substrate overlaps with the hollowed-out position of the adhesive layer on the first substrate.

[0090] Example 2

[0091] The pressure sensing array is prepared by the following specific steps:

[0092] (1) using an ethanol solution, an acetone solution and deionized water to ultrasonically clean a first substrate and a second substrate both made of polyimide, drying them after cleaning, and treating the surfaces of the first substrate and the second substrate with oxygen plasma or ultraviolet light / ozone;

[0093] (2) preparing row electrodes and column electrodes on the upper surface of the first substrate and the lower surface of the second substrate respectively by inkjet printing;

[0094] (3) using a screen printing process to prepare a patterned pressure-sensitive layer on the surface of the row electrode and the column electrode to form the first pressure-sensitive layer and the second pressure-sensitive layer, wherein the material of the first pressure-sensitive layer and the material of the second pressure-sensitive layer are both polyimide and polycarbonate doped with nanographite particles, and the doping concentration is 5%; the first pressure-sensitive layer, the second pressure-sensitive layer, the row electrode and the column electrode are aligned and overlapped;

[0095] (4) forming an array of hollow (i.e., the opening) patterns on the surface of the double-sided adhesive tape (i.e., the adhesive layer) by laser cutting, wherein the spacing of the hollow patterns is consistent with the spacing of the row / column electrodes; attaching the double-sided adhesive tape to the surface of the row / column electrodes, wherein the hollow positions of the double-sided adhesive tape overlap with the first pressure-sensitive layer and the second pressure-sensitive layer;

[0096] (5) The second substrate is bonded to the double-sided adhesive surface, and the second pressure-sensitive layer on the second substrate overlaps with the hollowed-out position of the adhesive layer on the first substrate.

[0097] Example 3

[0098] The pressure sensing array is prepared by the following specific steps:

[0099] (1) ultrasonically cleaning a first substrate and a second substrate both made of polyethylene naphthalate using an ethanol solution, an acetone solution, and deionized water, drying the substrate after cleaning, and treating the surfaces of the first substrate and the second substrate using oxygen plasma or ultraviolet light / ozone;

[0100] (2) preparing row electrodes and column electrodes on the upper surface of the first substrate and the lower surface of the second substrate respectively by sputtering;

[0101] (3) using a screen printing process to prepare a patterned pressure-sensitive layer on the surface of the row electrode and the column electrode to form the first pressure-sensitive layer and the second pressure-sensitive layer, wherein the material of the first pressure-sensitive layer and the material of the second pressure-sensitive layer are both polyimide and polyamide doped with carbon nanotubes, and the doping concentration is 0.5%; the first pressure-sensitive layer, the second pressure-sensitive layer, the row electrode and the column electrode are aligned and overlapped;

[0102] (4) forming an array of hollow (i.e., the opening) patterns on the surface of the double-sided adhesive tape (i.e., the adhesive layer) by laser cutting, wherein the spacing of the hollow patterns is consistent with the spacing of the row / column electrodes; attaching the double-sided adhesive tape to the surface of the row / column electrodes, wherein the hollow positions of the double-sided adhesive tape overlap with the first pressure-sensitive layer and the second pressure-sensitive layer;

[0103] (5) The second substrate is bonded to the double-sided adhesive surface, and the second pressure-sensitive layer on the second substrate overlaps with the hollowed-out position of the adhesive layer on the first substrate.

[0104] Example 4

[0105] The pressure sensing array is prepared by the following specific steps:

[0106] (1) using an ethanol solution, an acetone solution and deionized water to ultrasonically clean a first substrate and a second substrate both made of polyimide, drying them after cleaning, and treating the surfaces of the first substrate and the second substrate with oxygen plasma or ultraviolet light / ozone;

[0107] (2) preparing row electrodes and column electrodes on the upper surface of the first substrate and the lower surface of the second substrate respectively by sputtering;

[0108] (3) using a screen printing process to prepare a patterned pressure-sensitive layer on the surface of the row electrode and the column electrode to form the first pressure-sensitive layer and the second pressure-sensitive layer, wherein the material of the first pressure-sensitive layer and the material of the second pressure-sensitive layer are both phenolic resin and polycarbonate doped with nanographite particles, and the doping concentration is 5%; the first pressure-sensitive layer, the second pressure-sensitive layer, the row electrode and the column electrode are aligned and overlapped;

[0109] (4) forming an array of hollow (i.e., the opening) patterns on the surface of the double-sided adhesive tape (i.e., the adhesive layer) by laser cutting, wherein the spacing of the hollow patterns is consistent with the spacing of the row / column electrodes; attaching the double-sided adhesive tape to the surface of the row / column electrodes, wherein the hollow positions of the double-sided adhesive tape overlap with the first pressure-sensitive layer and the second pressure-sensitive layer;

[0110] (5) The second substrate is bonded to the double-sided adhesive surface, and the second pressure-sensitive layer on the second substrate overlaps with the hollowed-out position of the adhesive layer on the first substrate.

[0111] Example 5

[0112] The pressure sensing array is prepared by the following specific steps:

[0113] (1) using an ethanol solution, an acetone solution and deionized water to ultrasonically clean a first substrate and a second substrate both made of polyimide, drying them after cleaning, and treating the surfaces of the first substrate and the second substrate with oxygen plasma or ultraviolet light / ozone;

[0114] (2) preparing row electrodes and column electrodes on the upper surface of the first substrate and the lower surface of the second substrate respectively by screen printing;

[0115] (3) using a screen printing process to prepare a patterned pressure-sensitive layer on the surface of the row electrode and the column electrode to form the first pressure-sensitive layer and the second pressure-sensitive layer, wherein the material of the first pressure-sensitive layer and the material of the second pressure-sensitive layer are both cross-linked unsaturated polyester and polystyrene doped with nanographene, and the doping concentration is 3%; the first pressure-sensitive layer, the second pressure-sensitive layer, the row electrode and the column electrode are aligned and overlapped;

[0116] (4) forming an array of hollow (i.e., the opening) patterns on the surface of the double-sided adhesive tape (i.e., the adhesive layer) by laser cutting, wherein the spacing of the hollow patterns is consistent with the spacing of the row / column electrodes; attaching the double-sided adhesive tape to the surface of the row / column electrodes, wherein the hollow positions of the double-sided adhesive tape overlap with the first pressure-sensitive layer and the second pressure-sensitive layer;

[0117] (5) The second substrate is bonded to the double-sided adhesive surface, and the second pressure-sensitive layer on the second substrate overlaps with the hollowed-out position of the adhesive layer on the first substrate.

[0118] Example 6

[0119] The pressure sensing array is prepared by the following specific steps:

[0120] (1) using an ethanol solution, an acetone solution and deionized water to ultrasonically clean a first substrate and a second substrate both made of polyimide, drying them after cleaning, and treating the surfaces of the first substrate and the second substrate with oxygen plasma or ultraviolet light / ozone;

[0121] (2) preparing row electrodes and column electrodes on the upper surface of the first substrate and the lower surface of the second substrate respectively by inkjet printing;

[0122] (3) using a screen printing process to prepare a patterned pressure-sensitive layer on the surface of the row electrode and the column electrode to form the first pressure-sensitive layer and the second pressure-sensitive layer, wherein the material of the first pressure-sensitive layer and the material of the second pressure-sensitive layer are both cross-linked epoxy resin and polycarbonate doped with nanographene, and the doping concentration is 10%; the first pressure-sensitive layer, the second pressure-sensitive layer, the row electrode and the column electrode are aligned and overlapped;

[0123] (4) forming an array of hollow (i.e., the opening) patterns on the surface of the double-sided adhesive tape (i.e., the adhesive layer) by laser cutting, wherein the spacing of the hollow patterns is consistent with the spacing of the row / column electrodes; attaching the double-sided adhesive tape to the surface of the row / column electrodes, wherein the hollow positions of the double-sided adhesive tape overlap with the first pressure-sensitive layer and the second pressure-sensitive layer;

[0124] (5) The second substrate is bonded to the double-sided adhesive surface, and the second pressure-sensitive layer on the second substrate overlaps with the hollowed-out position of the adhesive layer on the first substrate.

[0125] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A pressure sensor, characterized in that: include: A first substrate, comprising an upper surface and a lower surface that are oppositely distributed; A first sensing electrode, located on the upper surface of the first substrate; A first piezoresistive layer is located on a surface of the first sensing electrode facing away from the first substrate, the first piezoresistive layer being a first piezoresistive film layer having a microphase separation structure and a rough surface facing away from the first substrate; A second substrate, comprising an upper surface and a lower surface that are oppositely distributed, wherein the lower surface of the second substrate is arranged toward the upper surface of the first substrate; A second sensing electrode is located on the lower surface of the second substrate; The second piezoresistive layer is located on the surface of the second sensing electrode facing away from the second substrate. The second piezoresistive layer is a second piezoresistive film layer with microphase separation and a rough surface facing away from the second substrate.

2. The pressure sensor according to claim 1, characterized in that: The roughness of a surface of the first piezoresistive film layer facing away from the first substrate and the roughness of a surface of the second piezoresistive film layer facing away from the second substrate are both in the range of 100 nanometers to 50 micrometers.

3. The pressure sensor according to claim 1, characterized in that: The material of the first piezoresistive film layer and the material of the second piezoresistive film layer are both block polymers doped with conductive nanomaterials or mixed materials of thermoplastic polymers and thermosetting polymers doped with conductive nanomaterials. The thermoplastic polymers include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide, polyformaldehyde, polycarbonate, polyphenylene ether, and polysulfone. The thermosetting polymer materials include phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, epoxy resin, unsaturated resin, polyurethane, and polyimide.

4. The pressure sensor according to claim 3, characterized in that: The conductive nanomaterial is any one of nano-carbon powder, nano-graphite, carbon nanotube and nano-graphene, or a combination of two or more thereof, and the conductive nanomaterial has a diameter of 20 nanometers to 10 micrometers; The conductive nanomaterials doped in the polymer include a variety of different diameters, and the maximum diameter of the doped conductive nanomaterials is less than 3 times the minimum diameter or the maximum diameter of the doped conductive nanomaterials is more than 5 times the minimum diameter.

5. The pressure sensor according to claim 3, characterized in that: The doping concentration of the conductive nano material in the polymer is 0.5% to 10%, and the doping concentrations of the conductive nano material in the thermoplastic polymer and the thermosetting polymer are the same or different.

6. The pressure sensor according to claim 1, characterized in that: The first piezoresistive film layer and the second piezoresistive film layer both include a leveling agent, a defoaming agent, a diluent and a conductive nanomaterial dispersant.

7. The pressure sensor according to claim 1, characterized in that: The materials of the first sensing electrode and the second sensing electrode are any one of conductive polymers, carbon-based conductors, metal oxides, metal nanowires, metal and metal oxide nanoparticles, and conductive pastes based on carbon-based conductors, metal nanowires, metal and metal oxide nanoparticles.

8. A pressure sensing array, characterized in that: include: A plurality of pressure sensors according to any one of claims 1 to 7, wherein the plurality of pressure sensors are arranged in an array; The first sensing electrodes in the plurality of pressure sensors arranged in the same row are electrically connected and collectively serve as row electrodes; The second sensing electrodes in the plurality of pressure sensors arranged in the same column are electrically connected and collectively serve as column electrodes, and the column electrodes are arranged orthogonally to the row electrodes; The pressure sensing array also includes an adhesive layer, which is sandwiched between the first substrate and the second substrate, and has a plurality of openings corresponding to the plurality of pressure sensors. The first pressure-sensitive layer and the second pressure-sensitive layer in each of the pressure sensors are located in the openings corresponding thereto, and the position of each of the openings is aligned with the first sensing electrode and the second sensing electrode in one of the pressure sensors.

9. A method for preparing a pressure sensing array as claimed in claim 8, characterized in that: The steps include: providing a first substrate and a second substrate; forming the row electrodes on the upper surface of the first substrate, and forming the column electrodes on the lower surface of the second substrate; forming a first pressure-sensitive layer covering the row electrodes, and forming a second pressure-sensitive layer covering the column electrodes, wherein the size of the first pressure-sensitive layer is the same as the size of the second pressure-sensitive layer; forming an adhesive layer on the upper surface of the first substrate, wherein the adhesive layer has a plurality of openings exposing the first pressure-sensitive layer; The second substrate is attached to the adhesive layer along a direction in which the second pressure-sensitive layer is aligned with the first pressure-sensitive layer, so that the row electrodes and the column electrodes are arranged orthogonally.

10. The method for preparing a pressure sensing array according to claim 9, characterized in that: The row electrodes, the column electrodes, the first pressure-sensitive layer and the second pressure-sensitive layer are all prepared by screen printing, scraping or spraying; The adhesive layer is prepared by laser cutting a double-sided adhesive film, dispensing, screen printing, scraping or spraying.

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