A flexible pressure sensor with a staggered skeleton structure and a preparation method thereof

Abstract

The present invention discloses a flexible pressure sensor with an interlaced skeleton structure and a method for preparing the same. The sensor includes a protective layer, an electrode layer, an upper sensitive structure layer, and a lower sensitive structure layer. The upper sensitive structure layer includes an upper skeleton and an upper filling structure, the upper skeleton having a plurality of first arched protrusions, and the lower sensitive structure layer includes a lower skeleton and a lower filling structure, the lower skeleton having a plurality of second arched protrusions. The plurality of first arched protrusions and the plurality of second arched protrusions are interlaced and embedded in sequence. When subjected to pressure, the first arched protrusions can press against the lower filling structure, and the second arched protrusions can press against the upper filling structure, thereby increasing the contact area between the upper sensitive structure layer and the lower sensitive structure layer, increasing the conductive path, and improving the sensitivity of the sensor. The sensor can be directly manufactured using a low-cost reverse molding method, has simple packaging, is more convenient for use and maintenance, and the production mold can be reused, which is conducive to large-scale manufacturing.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a flexible pressure sensor with a staggered skeleton structure and a preparation method thereof. Background Art

[0002] In recent years, with the development of emerging technologies, market demand for smart wearable devices has been growing. As the sensor for smart wearable devices to interact with external information, flexible sensors have become a research hotspot due to their bendability and stretchability, making them easily adaptable to wearable devices. Flexible pressure sensors are a key research area. Currently, common flexible pressure sensors can be categorized into piezoresistive, capacitive, and piezoelectric types based on their signal conversion mechanisms. Piezoresistive flexible sensors offer advantages such as simple structure, low power consumption, high sensitivity, and easy signal acquisition.

[0003] The function of a resistive flexible pressure sensor is to convert external pressure stimuli into electrical signals, of which the sensitive piezoresistive layer plays a crucial role in this function and largely determines the electrical performance of the sensor. When pressure is applied, the sensor's microstructure layer increases the contact area between the upper and lower layers through its own compression deformation, causing changes in contact resistance and body resistance, thereby increasing the conduction circuit. However, currently common sensitive microstructures are mainly simple geometric microstructures such as interlocking structures, microsphere arrays, micropyramid arrays, and microcolumn arrays. This type of traditional microstructure has the problems of limited maximum contact area, complex preparation, single sensitive layer material, insensitivity to low-pressure stimulus detection, and easy deformation and saturation at high pressure, resulting in decreased sensitivity. In addition, the sensitive microstructure layer of current flexible tactile sensors is usually prepared using only a single material, which limits its sensitivity and stability over a wide range of extreme measurements. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a flexible pressure sensor with a staggered skeleton structure, which can improve the sensitivity of the sensor, broaden the detection range of the sensor, and enhance the performance of the sensor.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is as follows: a flexible pressure sensor with a staggered skeleton structure, which includes a protective layer, an electrode layer and a sensitive structure layer from the outside to the inside, and the sensitive structure layer includes an upper sensitive structure layer and a lower sensitive structure layer; the upper sensitive structure layer includes an upper skeleton and an upper filling structure embedded in the upper skeleton, the upper skeleton has a first arched protrusion protruding downward, the lower sensitive structure layer includes a lower skeleton and a lower filling structure embedded in the lower skeleton, the lower skeleton has a second arched protrusion protruding upward, wherein the upper skeleton and the lower skeleton are both distributed in plurality along the first direction, and the plurality of first arched protrusions and the plurality of second arched protrusions are staggered and embedded in sequence, so that the first arched protrusion can contact the lower filling structure, and the second arched protrusion can Able to contact with the upper filling structure; the first arched protrusion includes a plurality of first semicircular rings, and the plurality of first semicircular rings are distributed along the second direction, and a first embedding position is provided between each adjacent two first semicircular rings; the upper filling structure has a plurality of first embedding protrusions, and the plurality of first embedding protrusions are distributed along the second direction, and the plurality of first embedding protrusions are embedded one by one in the plurality of first embedding positions; the second arched protrusion includes a plurality of second semicircular rings, and the plurality of second semicircular rings are distributed along the second direction, and a second embedding position is provided between each adjacent two second semicircular rings; the lower filling structure has a plurality of second embedding protrusions, and the plurality of second embedding protrusions are distributed along the second direction, and the plurality of second embedding protrusions are embedded one by one in the plurality of second embedding positions; wherein, the first direction and the second direction are coplanar and perpendicular to each other.

[0006] The above-mentioned flexible pressure sensor with an interlaced skeleton structure has a first recess formed between each adjacent two first arched protrusions, and a second recess formed between each adjacent two second arched protrusions. In the second direction, multiple first semi-circular rings and multiple second semi-circular rings are staggered in sequence; in the first direction, the first semi-circular ring can be embedded in a corresponding second recess and contact and combine with the second embedded protrusions on both sides of the second recess, and the second semi-circular ring can be embedded in a corresponding first recess and contact and combine with the first embedded protrusions on both sides of the first recess.

[0007] The above-mentioned flexible pressure sensor with an interlaced skeleton structure has an elastic modulus of the upper filling structure that is smaller than the elastic modulus of the upper skeleton, and both the upper skeleton and the upper filling structure can be deformed under pressure; the elastic modulus of the lower filling structure is smaller than the elastic modulus of the lower skeleton, and both the lower skeleton and the lower filling structure can be deformed under pressure.

[0008] In the above-mentioned flexible pressure sensor with a staggered skeleton structure, the lower surface of the first embedded protrusion and the upper surface of the second embedded protrusion are both semicircular arc surfaces.

[0009] The above-mentioned flexible pressure sensor with an interlaced skeleton structure, the protective layer includes an upper protective layer and a lower protective layer, the electrode layer includes an upper electrode layer and a lower electrode layer, the upper skeleton and the lower skeleton are respectively connected to the inner side surfaces of the upper electrode layer and the lower electrode layer, and the upper protective layer and the lower protective layer are respectively encapsulated on the outer side surfaces of the upper electrode layer and the lower electrode layer.

[0010] In the above-mentioned flexible pressure sensor with a staggered skeleton structure, the electrode layer is rectangular, the length of the electrode layer is greater than the length of the sensitive structure layer, and the width of the electrode layer is greater than the width of the sensitive structure layer.

[0011] The above-mentioned flexible pressure sensor with an interlaced skeleton structure, the material of the protective layer is one of polyimide, copolyester, polyvinyl alcohol, and silicone rubber materials; the material of the electrode layer is a carbon-based conductive silicone material; the material of the upper skeleton and the lower skeleton is an elastic silicone material coated with a conductive layer on the surface; the material of the upper filling structure and the lower filling structure is a conductive polymer material.

[0012] In the above-mentioned flexible pressure sensor with a staggered skeleton structure, the carbon-based conductive silicone material is one of carbon nanotubes, carbon fibers, graphene, and conductive carbon black.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects:

[0014] 1. The sensitive structure layer of this sensor includes multiple frames and filling structures, and the first arched protrusions of the multiple upper frames and the second arched protrusions of the multiple lower frames are interlaced and embedded in sequence, thereby increasing the contact area between the upper sensitive structure layer and the lower sensitive structure layer and increasing the conductive path. When pressurized, the first arched protrusions can press and contact with the lower filling structure, and the second arched protrusions can press and contact with the upper filling structure. The sensitive structure layer is easy to deform, thereby improving the sensitivity of the sensor;

[0015] 2. In the sensitive structural layer of the sensor, a filling structure is embedded in the skeleton. The filling structure and the skeleton are made of different materials, and the elastic modulus of the filling structure is smaller than that of the skeleton. This allows the advantages of the two materials to be complementary and combined. When the contact pressure is small, the first arched protrusions and the second arched protrusions are alternately embedded in sequence. The filling structure with a smaller elastic modulus is first compressed by the skeleton and deformed, thereby causing a significant change in the resistivity of the entire conductive path, further improving the sensitivity of the sensor. When the contact pressure is large, as the filling structure approaches the deformation limit, the skeleton will be further compressed and deformed as the pressure increases, still causing the resistivity of the entire conductive circuit to change, further improving the overall elastic modulus of the sensor and extending the maximum detection range of the sensor.

[0016] The present invention also provides a method for preparing a flexible pressure sensor having a staggered skeleton structure, which is used to prepare the flexible pressure sensor having a staggered skeleton structure, comprising the following steps:

[0017] S1, preparing electrode layer, filling structure and skeleton mold;

[0018] S2, mixing silica gel and curing agent, pouring into the skeleton mold, heating and curing, and peeling to obtain the skeleton base;

[0019] S3, using a plasma sputtering coating method to cover the skeleton base with a conductive layer to obtain a skeleton, wherein the skeleton includes an upper skeleton and a lower skeleton;

[0020] S4, pouring polydimethylsiloxane (PDMS) and Na2CO3 crystals into the filling structure mold, heating and curing, peeling off and placing in clean water until the Na2CO3 crystals are completely dissolved to obtain a porous PDMS sponge;

[0021] S5, dipping the porous PDMS sponge in the carbon nanotube solution and then drying it to obtain a filling structure, wherein the filling structure includes an upper filling structure and a lower filling structure;

[0022] S6. embedding the upper filling structure and the lower filling structure into the upper frame and the lower frame respectively to obtain the upper sensitive layer structure and the lower sensitive layer structure;

[0023] S7, repeating steps S2 to S6 to obtain multiple upper sensitive layer structures and multiple lower sensitive layer structures;

[0024] S8. Mixing silica gel, a curing agent, and a carbon-based conductive material successively and stirring evenly to obtain a carbon-based conductive silica gel solution, pouring the solution into an electrode layer mold, placing multiple upper sensitive layer structures / multiple lower sensitive layer structures, heating and curing, and peeling off to obtain an electrode-sensitive layer structure, wherein the electrode-sensitive layer structure includes an upper electrode-sensitive layer structure and a lower electrode-sensitive layer structure;

[0025] S9, the upper electrode-sensitive layer structure and the lower electrode-sensitive layer structure prepared in step S8 are staggered and embedded in a skeleton and packaged, and protective layers are packaged on the upper and lower surfaces to obtain a flexible pressure sensor with a staggered skeleton structure.

[0026] Compared with the existing technology, the beneficial effects of this preparation method are: the flexible pressure sensor is directly manufactured using a low-cost reverse molding method, the packaging is simple, it is easier to use and maintain, and the production mold can be reused, which is conducive to large-scale and economical production.

[0027] In the above-mentioned method for preparing a flexible pressure sensor with an interlaced skeleton structure, in step S3, a conductive layer is covered on the skeleton substrate by plasma sputtering or evaporation, wherein the conductive layer is a silver coating.

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the structure of a flexible pressure sensor according to an embodiment of the present invention;

[0030] Figure 2 is a schematic diagram of a sensitive structural layer according to an embodiment of the present invention;

[0031] Figure 3 A schematic structural diagram of a skeleton according to an embodiment of the present invention;

[0032] Figure 4 A schematic structural diagram of a filling structure according to an embodiment of the present invention;

[0033] Figure 5 Schematic diagram of the preparation of a flexible pressure sensor according to an embodiment of the present invention.

[0034] Explanation of the accompanying numbers: 100-protective layer, 110-upper protective layer, 120-lower protective layer, 200-electrode layer, 210-upper electrode layer, 220-lower electrode layer, 300-upper sensitive structure layer, 310 upper skeleton, 311 first arched protrusion, 320 upper filling structure, 400-lower sensitive structure layer, 410-lower skeleton, 411-second arched protrusion, 4111-second semicircular ring, 412-strip-shaped connecting structure, 413-second embedding position, 420-lower filling structure, 421-second embedding protrusion, 422-second card slot. DETAILED DESCRIPTION

[0035] Reference Figures 1 to 4 The present invention provides a flexible pressure sensor with a staggered skeleton structure. The sensor includes a protective layer 100, an electrode layer 200 and a sensitive structure layer from the outside to the inside. The protective layer 100 includes an upper protective layer 110 and a lower protective layer 120, the electrode layer 200 includes an upper electrode layer 210 and a lower electrode layer 220, and the sensitive structure layer includes an upper sensitive structure layer 300 and a lower sensitive structure layer 400.

[0036] Among them, reference Figure 1 and Figure 2 The upper sensitive structure layer 300 includes an upper frame 310 and an upper filling structure 320 embedded within the upper frame 310. The upper frame 310 is connected to the inner side of the upper electrode layer 210, and the upper protective layer 110 is encapsulated on the outer side of the upper electrode layer 210. The upper electrode layer 210 is rectangular, with a length slightly greater than the length of the upper sensitive structure layer 300 and a width slightly greater than the width of the upper sensitive structure layer 300. The upper frame 310 has a first arched protrusion 311 that protrudes downward. Similarly, the lower sensitive structure layer 400 includes a lower frame 410 and a lower filling structure 420 embedded within the lower frame 410. The lower frame 410 is connected to the inner side of the lower electrode layer 220, and the lower protective layer 120 is encapsulated on the outer side of the lower electrode layer 220. The lower electrode layer 220 is rectangular, with a length slightly greater than the length of the lower sensitive structure layer 400 and a width slightly greater than the width of the lower sensitive structure layer 400. The lower frame 410 has a second arched protrusion 411 that protrudes upward. Among them, Figure 3 and Figure 4 In the figure, only the lower skeleton 410 and the lower filling structure 420 are used as an example for numbering description, and the specific structures of the upper skeleton 310 and the upper filling structure 320 can refer to the lower skeleton 410 and the lower filling structure 420.

[0037] The upper frame 310 and the lower frame 410 are both distributed in a plurality along the first direction, wherein the first direction is the width direction. It is understandable that each upper frame 310 is embedded with an upper filling structure 320, and each lower frame 410 is embedded with a lower filling structure 420. Since the upper frame 310 and the lower frame 410 are both distributed in a plurality, the first arched protrusions 311 and the second arched protrusions 411 are also distributed in a plurality. A first recess is formed between each two adjacent first arched protrusions 311, and a second recess is also formed between each two adjacent second arched protrusions 411. The plurality of first arched protrusions 311 and the plurality of second arched protrusions 411 are sequentially staggered and embedded, that is, the first arched protrusions 311 can be embedded in a corresponding second recess and contact and combine with the lower filling structures 420 on both sides of the second recess, and the second arched protrusions 411 can be embedded in a corresponding first recess and contact and combine with the upper filling structures 320 on both sides of the first recess. At the same time, in the second direction (length direction), the first arched protrusion 311 and the second arched protrusion 411 are also staggered with each other, so that the first arched protrusion 311 can contact the lower filling structure 420 and the second arched protrusion 411 can contact the upper filling structure 320.

[0038] When no force is applied, the upper sensitive structural layer 300 and the lower sensitive structural layer 400 are in line contact with each other. When subjected to force, due to the interlaced arrangement of the upper and lower skeletons 310 and 410, the skeletons will squeeze the filling structure under pressure, resulting in an increase in contact area and a decrease in contact resistance. When the pressure increases further, the filling structure gradually reaches its limit of deformation, and the skeleton will deform as a whole under pressure, thereby further increasing the contact area and increasing the conductive path. Because the first arched protrusions 311 of the multiple upper skeletons 310 and the second arched protrusions 411 of the multiple lower skeletons 410 of this sensor are interlaced and interlaced, the contact area between the upper sensitive structural layer 300 and the lower sensitive structural layer 400 is increased, the conductive path is increased, and the sensitive structural layer is easily deformed when subjected to pressure, thereby improving the sensitivity of the sensor.

[0039] Furthermore, the first arc-shaped arch includes a plurality of first semicircular rings, which are distributed along the second direction and connected to the two strip-shaped connecting structures 412. A first embedding position is defined between each pair of adjacent first semicircular rings, wherein the second direction is the length direction. The upper filling structure 320 includes a plurality of first embedding protrusions, each of which has a semicircular arc surface on its lower surface. The plurality of first embedding protrusions are distributed along the second direction, and a first locking groove is defined between each pair of adjacent first embedding protrusions. The plurality of first embedding protrusions are embedded one by one in the plurality of first embedding positions, and the plurality of first semicircular rings are locked one by one in the plurality of first locking grooves. After embedding, the overall structure has a semi-cylindrical shape.

[0040] Similarly, refer to Figure 3The second arc-shaped arch includes a plurality of second semicircular rings 4111, which are distributed along the second direction and connected to the two strip-shaped connecting structures 412. A second embedding position 413 is provided between each two adjacent second semicircular rings 4111, wherein the second direction is the length direction. Figure 4 The lower filling structure 420 has a plurality of second embedded protrusions 421, the lower surface of the second embedded protrusions 421 is a semicircular arc surface, and the plurality of second embedded protrusions 421 are distributed along the second direction, and a second clamping groove 422 is provided between each two adjacent second embedded protrusions 421. The plurality of second embedded protrusions 421 are embedded one by one in the plurality of second embedded positions 413, and the plurality of second semicircular rings 4111 are clamped one by one in the plurality of second clamping grooves 422. After embedding, the overall structure is semi-cylindrical. In the prepared sensor structure, in the second direction, the plurality of first semicircular rings and the plurality of second semicircular rings 4111 are alternately distributed in sequence, the first semicircular rings can contact the second embedded protrusions 421, and the second semicircular rings 4111 can contact the first embedded protrusions.

[0041] Furthermore, the elastic modulus of the upper filling structure 320 is smaller than that of the upper frame 310, and both the upper frame 310 and the upper filling structure 320 can be deformed under pressure. The elastic modulus of the lower filling structure 420 is smaller than that of the lower frame 410, and both the lower frame 410 and the lower filling structure 420 can be deformed under pressure. Because the filling structure and the frame of this sensor are made of different materials, and the elastic modulus of the filling structure is smaller than that of the frame, the advantages of the two materials can be complemented and combined. When the contact pressure is low, due to the interlaced arrangement of the first arched protrusions 311 and the second arched protrusions 411, the filling structure with the smaller elastic modulus is first compressed by the frame and deformed, thereby causing a significant change in the resistivity of the entire conductive path, further improving the sensitivity of the sensor. When the contact pressure is high, as the filling structure approaches its deformation limit, the frame will further compress and deform as the pressure increases, still causing a change in the resistivity of the entire conductive path, further improving the overall elastic modulus of the sensor and extending the maximum detection range of the sensor. In addition, the materials of the skeleton and filling structure are highly interchangeable, and different material combinations can be selected to achieve different measurement performances. The performance of the sensor can be further improved with the research and development of related new materials.

[0042] Furthermore, the material of the protective layer 100 is one of polyimide, copolyester, polyvinyl alcohol, and silicone rubber materials. The good flexibility and bendability of materials such as polyimide (PI), copolyester, polyvinyl alcohol (PV), and silicone rubber materials can be used to well protect the internal structure of the sensor. The material of the electrode layer 200 is a carbon-based conductive silicone material such as carbon nanotubes, carbon fibers, graphene, and conductive carbon black. The base material of the upper skeleton 310 and the lower skeleton 410 is a silicone rubber material with a hardness of 40°. It can also be a common greenhouse vulcanized rubber such as GD401 and GD402. Silicone rubber has the advantages of good elasticity and plasticity, low price and easy preparation, and can be doped with conductive materials during preparation to improve the sensitivity of the sensor. The base of the upper skeleton 310 and the lower skeleton 410 is coated with a conductive layer. The material of the conductive layer can be gold, silver, or conductive silver paste, etc., which is used to form a conductive path between the corresponding sensitive layer. The material of the upper filling structure 320 and the lower filling structure 420 is a conductive polymer material, which can be a polydimethylsiloxane (PDMS) sponge impregnated with carbon nanotubes (CNTs). The characteristic that the resistance of the PDMS / CNTs sponge decreases and the output signal changes when it is under pressure can be utilized to ensure the detection sensitivity of the sensor at low pressure.

[0043] Example 1

[0044] Embodiment 1 of the present invention provides a flexible pressure sensor with a staggered skeleton structure, wherein the upper sensitive structure layer 300 includes 6-8 upper skeletons 310, each of which has an upper filling structure 320 embedded therein, and the lower sensitive structure layer 400 includes 6-8 lower skeletons 410, the number of lower skeletons 410 being the same as the number of upper skeletons 310, and each of which has a lower filling structure 420 embedded therein. Each upper skeleton 310 includes two strip-shaped connecting structures 412 and 6-10 first semicircular rings distributed along the length and connected to the strip-shaped connecting structures 412. The inner radius of each first semicircular ring is 20 mm, the material width of the first semicircular ring is 7.5 mm, the thickness is 5 mm, and the spacing between each two adjacent first semicircular rings is 25 mm, serving as the first embedding position. Each upper filling structure 320 is generally a semi-cylinder with a semi-circular groove. The semi-circular groove serves as the first clamping groove. The semi-circular protrusion between each two adjacent semi-circular grooves is the first embedding protrusion. The number of semi-circular grooves is consistent with the number of first semi-circular rings, and the groove width, groove depth and radius correspond to the material thickness, width and radius of the first semi-circular ring, which are 5mm, 7.5mm and 20mm respectively. The multiple first embedding protrusions of the upper filling structure 320 are embedded one by one in the multiple first embedding positions. At the same time, the multiple first clamping grooves are also clamped one by one with the multiple first semi-circular rings. The total length of the structure after the upper filling structure 320 is embedded in the upper skeleton 310 is 180 to 300mm.

[0045] Similarly, each lower skeleton 410 includes two strip-shaped connecting structures 412 and 6-10 second semi-circular rings 4111 distributed along the length direction and connected under the strip-shaped connecting structures 412. The inner radius of each second semi-circular ring 4111 is 20mm, the material width of the second semi-circular ring 4111 is 7.5mm, the thickness is 5mm, and the spacing between each two adjacent second semi-circular rings 4111 is 25mm, serving as the second embedding position 413. Each lower filling structure 420 is generally a semi-cylinder with a semi-circular groove. The semi-circular groove serves as the second clamping groove 422. The semi-circular protrusion between each two adjacent semi-circular grooves is the second embedding protrusion 421. The number of semi-circular grooves is consistent with the number of second semi-circular rings 4111, and the groove width, groove depth and radius correspond to the material thickness, width and radius of the second semi-circular ring 4111, which are 5mm, 7.5mm and 20mm respectively. The multiple second embedding protrusions 421 of the lower filling structure 420 are embedded one by one in the multiple second embedding positions 413. At the same time, the multiple second clamping grooves 422 are also clamped one by one with the multiple second semi-circular rings 4111. After the lower filling structure 420 is embedded in the lower frame 410, the total length of the structure is 180 to 300 mm.

[0046] Example 2

[0047] Reference Figure 5 A second embodiment of the present invention provides a method for preparing a flexible pressure sensor having a staggered skeleton structure, which comprises the following steps:

[0048] S1, preparing electrode layer, filling structure and skeleton mold;

[0049] S2, mixing silica gel and curing agent, pouring into the skeleton mold, heating and curing, and peeling to obtain the skeleton base;

[0050] S3, covering the skeleton base with a conductive layer to obtain a skeleton, wherein the skeleton includes an upper skeleton 310 and a lower skeleton 410;

[0051] S4, pouring polydimethylsiloxane (PDMS) and Na2CO3 crystals into the filling structure mold, heating and curing, peeling off and placing in clean water until the Na2CO3 crystals are completely dissolved to obtain a porous PDMS sponge;

[0052] S5, dipping the porous PDMS sponge in the carbon nanotube solution and then drying it to obtain a filling structure, wherein the filling structure includes an upper filling structure 320 and a lower filling structure 420;

[0053] S6. Embed the upper filling structure 320 and the lower filling structure 420 into the upper frame 310 and the lower frame 410 respectively to obtain the upper sensitive layer structure and the lower sensitive layer structure;

[0054] S7, repeating steps S2 to S6 to obtain multiple upper sensitive layer structures and multiple lower sensitive layer structures;

[0055] S8. Mixing silica gel, a curing agent, and a carbon-based conductive material successively and stirring evenly to obtain a carbon-based conductive silica gel solution, pouring the solution into an electrode layer mold, placing multiple upper sensitive layer structures / multiple lower sensitive layer structures, heating and curing, and peeling off to obtain an electrode-sensitive layer structure, wherein the electrode-sensitive layer structure includes an upper electrode-sensitive layer structure and a lower electrode-sensitive layer structure;

[0056] S9. The upper electrode-sensitive layer structure and the lower electrode-sensitive layer structure prepared in step S8 are staggered and embedded in a skeleton and packaged together, and protective layers 100 are packaged on the upper and lower surfaces to obtain a flexible pressure sensor with a staggered skeleton structure.

[0057] This preparation method is used to prepare the above-mentioned flexible pressure sensor with an interlaced skeleton structure. The structures of each part of the sensor are simple and clear, and a relatively simple manufacturing process can be adopted. It can be directly manufactured using a low-cost reverse molding method. The packaging is simple and it is easier to use and maintain. The production mold can be reused, which is conducive to large-scale and economical production.

[0058] Furthermore, in step S1, the electrode layer, filling structure and skeleton mold can be modeled using software such as SolidWorks, and then the mold can be printed using a 3D printer to obtain the electrode layer mold, the filling structure mold and the skeleton mold.

[0059] In step S2, a silicone rubber material with a hardness of 40° is added to the skeleton mold, which is then placed in a vacuum drying oven for heating and curing, and a plurality of skeleton bases are obtained after demoulding.

[0060] In step S3, a conductive layer is coated on the skeleton substrate by plasma sputtering coating, evaporation or the like. The conductive layer may be made of gold, silver or conductive silver paste or the like.

[0061] In step S4, PDMS and Na2CO3 crystals are poured into the filling structure mold at a mass ratio of 20:1, and then placed in a vacuum drying oven for heating and curing for 20 to 60 minutes. After peeling, the mixture is placed in a beaker containing deionized water and stirred thoroughly. The solution in the beaker is continuously replaced with deionized water until the Na2CO3 crystals are completely dissolved, thereby obtaining a porous PDMS sponge.

[0062] In step S5, a multi-walled carbon nanotube solution with a mass fraction of 0.5% to 3% is prepared, and a porous PDMS sponge is immersed in the carbon nanotube solution for 25 to 30 minutes by an impregnation method, and then placed in a vacuum drying oven at 80 to 120° C. and dried for 0.5 to 2 hours to obtain a PDMS / CNTs sponge as a conductive filling structure;

[0063] In step S8, the silica gel and the curing agent are mixed in a mass ratio of 5:1 to 15:1, stirred evenly, and then 5 to 8% of multi-walled carbon nanotubes are added, and further stirred, ultrasonically dispersed and vacuum defoamed to obtain a carbon-based conductive silica gel solution, which is poured on the electrode layer mold, and the assembled multiple upper sensitive layer structures / multiple lower sensitive layer structures are placed thereon, and placed in a vacuum drying oven for heating and curing. After peeling, an integrated electrode-sensitive layer structure is obtained.

[0064] It should be noted that in the description of the present invention, if there are any descriptions of directions, such as up, down, front, back, left, right, etc., the directions or positional relationships indicated are all based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed or operate in a specific direction, and cannot be understood as a limitation on the present invention.

[0065] In the description of the present invention, "several" means one or more, "more" means two or more, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. If there are descriptions of "first," "second," and so on, these are used solely to distinguish technical features and are not to be construed as indicating or implying relative importance, or implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0066] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0067] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A flexible pressure sensor with a staggered skeleton structure, characterized in that: From the outside to the inside, the device comprises a protective layer (100), an electrode layer (200) and a sensitive structure layer, wherein the sensitive structure layer comprises an upper sensitive structure layer (300) and a lower sensitive structure layer (400); the upper sensitive structure layer (300) comprises an upper frame (310) and an upper filling structure (320) embedded in the upper frame (310), wherein the upper frame (310) has a first arched protrusion (311) protruding downward; the lower sensitive structure layer (400) comprises a lower frame (410) and a lower filling structure (420) embedded in the lower frame (410), wherein the lower frame (410) has a second arched protrusion (411) protruding upward; Wherein, the upper frame (310) and the lower frame (410) are both distributed in a plurality along the first direction, and the plurality of first arched protrusions (311) and the plurality of second arched protrusions (411) are sequentially interlaced and embedded, so that the first arched protrusions (311) can contact the lower filling structure (420), and the second arched protrusions (411) can contact the upper filling structure (320); The first arched protrusion (311) includes a plurality of first semicircular rings, the plurality of first semicircular rings are distributed along the second direction, and a first embedding position is provided between each two adjacent first semicircular rings. The upper filling structure (320) includes a plurality of first embedding protrusions, the plurality of first embedding protrusions are distributed along the second direction, and the plurality of first embedding protrusions are embedded one by one in the plurality of first embedding positions. The second arched protrusion (411) includes a plurality of second semicircular rings (4111), the plurality of second semicircular rings (4111) are distributed along the second direction, and a second embedding position (413) is provided between each two adjacent second semicircular rings (4111). The lower filling structure (420) includes a plurality of second embedding protrusions (421), the plurality of second embedding protrusions (421) are distributed along the second direction, and the plurality of second embedding protrusions (421) are embedded one by one in the plurality of second embedding positions (413); The first direction and the second direction are coplanar and perpendicular to each other.

2. The flexible pressure sensor with a staggered skeleton structure according to claim 1, characterized in that: A first recess is formed between each adjacent two first arched protrusions (311), and a second recess is formed between each adjacent two second arched protrusions (411). In the second direction, a plurality of the first semicircular rings and a plurality of the second semicircular rings (4111) are alternately distributed in sequence; In the first direction, the first semicircular ring can be embedded in one of the second recesses corresponding thereto, and contact and combine with the second embedding protrusions (421) on both sides of the second recess; the second semicircular ring (4111) can be embedded in one of the first recesses corresponding thereto, and contact and combine with the first embedding protrusions on both sides of the first recess.

3. The flexible pressure sensor with a staggered skeleton structure according to claim 1, characterized in that: The elastic modulus of the upper filling structure (320) is smaller than the elastic modulus of the upper skeleton (310), and both the upper skeleton (310) and the upper filling structure (320) can be deformed under pressure; the elastic modulus of the lower filling structure (420) is smaller than the elastic modulus of the lower skeleton (410), and both the lower skeleton (410) and the lower filling structure (420) can be deformed under pressure.

4. The flexible pressure sensor with a staggered skeleton structure according to claim 1, characterized in that: The lower surface of the first embedded protrusion and the upper surface of the second embedded protrusion (421) are both semicircular arc surfaces.

5. The flexible pressure sensor with a staggered skeleton structure according to claim 1, characterized in that: The protective layer (100) comprises an upper protective layer (110) and a lower protective layer (120); the electrode layer (200) comprises an upper electrode layer (210) and a lower electrode layer (220); the upper skeleton (310) and the lower skeleton (410) are respectively connected to the inner side surfaces of the upper electrode layer (210) and the lower electrode layer (220); and the upper protective layer (110) and the lower protective layer (120) are respectively encapsulated on the outer side surfaces of the upper electrode layer (210) and the lower electrode layer (220).

6. The flexible pressure sensor with a staggered skeleton structure according to claim 1, characterized in that: The electrode layer (200) is rectangular, the length of the electrode layer (200) is greater than the length of the sensitive structure layer, and the width of the electrode layer (200) is greater than the width of the sensitive structure layer.

7. The flexible pressure sensor with a staggered skeleton structure according to claim 1, characterized in that: The material of the protective layer (100) is one of polyimide, copolyester, polyvinyl alcohol, and silicone rubber; the material of the electrode layer (200) is a carbon-based conductive silicone material; the material of the upper skeleton (310) and the lower skeleton (410) is an elastic silicone material with a conductive layer coated on the surface; and the material of the upper filling structure (320) and the lower filling structure (420) is a conductive polymer material.

8. The flexible pressure sensor with a staggered skeleton structure according to claim 7, characterized in that: The carbon-based conductive silicone material is one of carbon nanotubes, carbon fibers, graphene, and conductive carbon black.

9. A method for preparing a flexible pressure sensor having a staggered skeleton structure, characterized in that: The method for preparing the flexible pressure sensor having an interlaced skeleton structure according to any one of claims 1 to 8 comprises the following steps: S1, preparing electrode layer, filling structure and skeleton mold; S2, mixing silica gel and curing agent, pouring into the skeleton mold, heating and curing, and peeling to obtain the skeleton base; S3, using a plasma sputtering coating method to cover a conductive layer on the skeleton base to obtain a skeleton, wherein the skeleton includes an upper skeleton (310) and a lower skeleton (410); S4, pouring polydimethylsiloxane and Na2CO3 crystals into the filling structure mold, heating and curing, peeling and placing in clean water until the Na2CO3 crystals are completely dissolved to obtain a porous PDMS sponge; S5, dipping the porous PDMS sponge in the carbon nanotube solution and then drying it to obtain a filling structure, wherein the filling structure includes an upper filling structure (320) and a lower filling structure (420); S6. Embedding the upper filling structure (320) and the lower filling structure (420) into the upper frame (310) and the lower frame (410) respectively to obtain an upper sensitive layer structure and a lower sensitive layer structure; S7, repeating steps S2 to S6 to obtain multiple upper sensitive layer structures and multiple lower sensitive layer structures; S8. Mixing silica gel, a curing agent, and a carbon-based conductive material successively and stirring evenly to obtain a carbon-based conductive silica gel solution, pouring the solution into an electrode layer mold, placing multiple upper sensitive layer structures / multiple lower sensitive layer structures, heating and curing, and peeling off to obtain an electrode-sensitive layer structure, wherein the electrode-sensitive layer structure includes an upper electrode-sensitive layer structure and a lower electrode-sensitive layer structure; S9, the upper electrode-sensitive layer structure and the lower electrode-sensitive layer structure prepared in step S8 are staggered and embedded in a skeleton for matching packaging, and protective layers (100) are packaged on the upper and lower surfaces to obtain a flexible pressure sensor with a staggered skeleton structure.

10. The method for preparing a flexible pressure sensor having a staggered skeleton structure according to claim 9, characterized in that: In step S3, a conductive layer is coated on the skeleton substrate by plasma sputtering or evaporation, wherein the conductive layer is a silver coating.

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