Bending-pressing dual-mode flexible sensor suitable for large deformation and preparation method thereof

Abstract

The invention belongs to the technical field of flexible sensing, and particularly relates to a bending-pressing dual-mode flexible sensor suitable for large deformation and a preparation method of the bending-pressing dual-mode flexible sensor. The dual-mode flexible sensor comprises a transverse substrate protection layer, a transverse sensing layer, a packaging isolation layer, a longitudinal sensing layer and a longitudinal substrate protection layer which are sequentially arranged from top to bottom, the transverse sensing layer comprises a plurality of first flexible sensing units arranged in parallel in the transverse direction, first wires are arranged at the two ends of each first flexible sensing unit, and second wires are arranged at the two ends of each first flexible sensing unit. The first wires form a first electrode array; the longitudinal sensing layer comprises a plurality of second flexible sensing units which are arranged in parallel in the longitudinal direction, second wires are arranged at the two ends of each second flexible sensing unit, and the second wires form a second electrode array; the first flexible sensing units and the second flexible sensing units are crosswise arranged in a grid distribution mode to form an orthogonalization two-dimensional sensing array network. According to the invention, high-sensitivity, large-deformation-capacity and multi-mode signal detection can be realized at the same time.

Description

Technical Field

[0001] This application belongs to the field of flexible sensing technology, and specifically relates to a bending-pressing dual-mode flexible sensor suitable for large deformation and its fabrication method. Background Technology

[0002] Flexible sensing technology has significant application value in fields such as medical rehabilitation, human-computer interaction, and virtual reality. However, existing flexible sensor technologies still face many challenges: traditional sensors can usually only detect a single physical quantity, such as strain or pressure, making it difficult to achieve simultaneous sensing of multimodal signals such as bending, stretching, and touch. For example, although sensors based on the principle of resistance strain can detect bending deformation, their response to pressure signals is weak; while capacitive pressure sensors, although highly sensitive to touch, cannot adapt to applications with large deformations due to their structural rigidity or thickness limitations.

[0003] In terms of materials and structure, most flexible sensors currently use rigid substrates such as polyimide (PI) or polyethylene terephthalate (PET). Their high Young's modulus necessitates significant external forces to drive deformation, increasing system energy consumption and limiting compatibility with soft materials. Furthermore, commonly used conductive materials (such as liquid metals or metal nanowires) are prone to breakage or disruption of the conductive network under tension, leading to a significant decrease in signal stability. Regarding performance, existing technologies often struggle to simultaneously meet the demands for high sensitivity, large strain range, and multimodal sensing. For example, some sensors improve pressure sensitivity through complex microstructure designs, sacrificing tensile performance; while sensors based on elastomers (such as silicone) can achieve large deformations, their signal linearity and repeatability are typically poor.

[0004] Therefore, there is an urgent need for a technical solution to overcome or mitigate at least one of the aforementioned defects in the existing technology. Summary of the Invention

[0005] The purpose of this application is to provide a bending-pressing dual-mode flexible sensor suitable for large deformation and its fabrication method, so as to solve the problem that existing flexible sensors are difficult to achieve high sensitivity, large strain range and multimodal sensing at the same time.

[0006] The technical solution of this application is:

[0007] The first aspect of this application provides a bending-pressing dual-mode flexible sensor suitable for large deformations, characterized in that it comprises: a lateral substrate protective layer, a lateral sensing layer, an encapsulation isolation layer, a longitudinal sensing layer, and a longitudinal substrate protective layer arranged sequentially from top to bottom, wherein...

[0008] The lateral sensing layer includes a plurality of first flexible sensing units arranged in parallel along the lateral direction. Each of the first flexible sensing units has a first wire at both ends, and the first wire forms a first electrode array.

[0009] The longitudinal sensing layer includes a plurality of second flexible sensing units arranged in parallel along the longitudinal direction. The two ends of the second flexible sensing units are provided with second wires, and the second wires form a second electrode array.

[0010] The first flexible sensing unit and the second flexible sensing unit are arranged in a grid pattern to form an orthogonal two-dimensional sensing array network.

[0011] In at least one embodiment of this application, the lateral substrate protective layer, the encapsulation isolation layer, and the longitudinal substrate protective layer are all made of an elastic material, which is one of silicone rubber, polyurethane, and hydrogel.

[0012] In at least one embodiment of this application, both the first flexible sensing unit and the second flexible sensing unit are made of carbon-based composite material composed of conductive functional material and elastic material.

[0013] In at least one embodiment of this application, the parameters of the dual-mode flexible sensor satisfy the following constraints:

[0014] Flexible sensing unit spacing constraints:

[0015] |d x -d γ |≤β1·min(d x ,d γ )

[0016] Where, d x d represents the spacing between the first flexible sensing units. γ β1 is the spacing between the second flexible sensing units and β2 is the constraint coefficient for the spacing between the flexible sensing units.

[0017] Encapsulation isolation layer thickness constraints:

[0018] β2·d x ≤t≤β3·d x

[0019] β2·d γ ≤t≤β3·d γ

[0020] Where t is the thickness of the encapsulation isolation layer, and β2 and β3 are the constraint coefficients for the thickness of the encapsulation isolation layer;

[0021] On-resistance constraint:

[0022]

[0023] Where R is the on-resistance, R 下 R is the lower limit of the on-resistance. 上 ρ is the upper limit of the on-resistance, l is the resistivity of the flexible sensing unit material, w is the length of the conductive path, h is the width of the conductive path, and h is the thickness of the conductive path.

[0024] Sensor total thickness constraint:

[0025] T≤T 上

[0026] Where T is the total thickness of the sensor, T 上 This represents the upper limit of the total thickness of the sensor.

[0027] In at least one embodiment of this application, the dual-mode flexible sensor is determined to meet performance requirements by calculating a sensor performance factor, wherein the sensor performance factor Ф is:

[0028]

[0029] The pressure sensitivity S is:

[0030]

[0031] Where k is the adjustment coefficient and E is the Young's modulus of the flexible sensing unit material;

[0032] Effective spatial resolution coefficient for:

[0033]

[0034] Where λ is the signal attenuation coefficient of the encapsulation isolation layer material, and d is the spacing between the flexible sensing units;

[0035] The shape factor Q is:

[0036]

[0037] Where A is the cross-sectional area of ​​the flexible sensing unit, and P is the perimeter of the flexible sensing unit cross-section;

[0038] The response time τ is:

[0039]

[0040] Where ε0 is the dielectric constant;

[0041] The channel coupling interference level η is:

[0042]

[0043] Among them, Corr(R)x ,R γ R represents the electrical signal correlation between the lateral sensing layer and the longitudinal sensing layer. x R represents the change in resistance of the lateral sensing layer. γ denoted as the change in resistance of the longitudinal sensing layer, and 'a' as the arrangement sparsity adjustment factor.

[0044] The second aspect of this application provides a method for fabricating a bending-pressing dual-mode flexible sensor suitable for large deformation, for fabricating the bending-pressing dual-mode flexible sensor suitable for large deformation as described above, comprising:

[0045] Step 1: Prepare carbon-based composite materials and form the transverse and longitudinal sensing layers;

[0046] Step 2: Spin-coating an elastic material onto the lateral sensing layer and the longitudinal sensing layer to form an encapsulation and isolation layer;

[0047] Step 3: Generate a multi-layer composite structure based on the lateral sensing layer, the encapsulation isolation layer, and the vertical sensing layer;

[0048] Step 4: The multi-layer composite structure is encapsulated a second time through a horizontal substrate protective layer and a vertical substrate protective layer to generate a dual-mode flexible sensor.

[0049] In at least one embodiment of this application, step one involves preparing a carbon-based composite material and forming a transverse sensing layer and a longitudinal sensing layer, including:

[0050] S101. The conductive functional material and the elastic material are mixed in a preset ratio, and after thorough stirring, the mixture is placed in a vacuum chamber to degas, forming a carbon-based composite material.

[0051] S102. Inject the carbon-based composite material into the syringe, and use the dispensing process to extrude multiple first flexible sensing units onto the transfer paper according to the preset trajectory to obtain the transverse sensing layer.

[0052] S103. Inject the carbon-based composite material into the syringe, and use the dispensing process to extrude multiple second flexible sensing units onto the transfer paper according to the preset trajectory to obtain the longitudinal sensing layer.

[0053] S104. When the carbon-based composite material is not cured, after the insulation layer of the wire is removed, the first flexible sensing unit and the second flexible sensing unit are inserted at a preset angle and depth, and the electrode array is formed after static curing.

[0054] In at least one embodiment of this application, step two, forming an encapsulation isolation layer by spin-coating an elastic material onto the lateral sensing layer and the longitudinal sensing layer, includes:

[0055] S201. Fix the transfer paper with the horizontal sensing layer and the vertical sensing layer onto the spin coating platform;

[0056] S202. A liquid elastic material is uniformly coated on the surface of the transverse sensing layer and the longitudinal sensing layer using a spin coating process, and after static curing, an encapsulation and isolation layer is formed.

[0057] In at least one embodiment of this application, step three, which involves generating a multilayer composite structure based on a lateral sensing layer, an encapsulation isolation layer, and a vertical sensing layer, includes:

[0058] S301. Fix the transfer paper with the transverse sensing layer onto the spin coating platform;

[0059] S302. A liquid elastic material is uniformly covered on the surface of the transverse sensing layer using a spin coating process. The transfer paper with the longitudinal sensing layer is aligned and bonded with the transfer paper with the transverse sensing layer to form a multi-layer composite structure of transfer paper-transverse sensing layer-encapsulation isolation layer-longitudinal sensing layer-transfer paper.

[0060] S303. Apply a preset pressure to the multi-layer composite structure to remove interlayer air bubbles, and allow it to cure statically.

[0061] In at least one embodiment of this application, in step four, the multilayer composite structure is secondary-encapsulated through a lateral substrate protective layer and a longitudinal substrate protective layer to generate a dual-mode flexible sensor, including:

[0062] S401. Fix the multi-layer composite structure to the spin coating platform;

[0063] S402. After softening one side of the multi-layer composite structure by spraying water, peel off the transfer paper with the transverse sensing layer, and use spin coating process to uniformly cover the surface of the transverse sensing layer with liquid elastic material. After static curing, a transverse base protective layer is formed.

[0064] S403. After softening the other side of the multi-layer composite structure by spraying water, peel off the transfer paper with the longitudinal sensing layer, and use a spin coating process to uniformly cover the surface of the longitudinal sensing layer with liquid elastic material. After static curing, a longitudinal base protective layer is formed.

[0065] The invention has at least the following beneficial technical effects:

[0066] This application discloses a bending-pressing dual-mode flexible sensor suitable for large deformation and its fabrication method, which can simultaneously achieve high sensitivity, large deformation capability, and multimodal signal detection with a simple structure. Based on carbon-based conductive materials and a flexible silicone substrate, an integrated sensor unit is constructed through dispensing and spin coating processes. This not only enables high-sensitivity bending-pressing dual-mode detection but also provides large deformation under low resistance, offering a high-performance sensing solution for applications such as medical monitoring, intelligent prosthetics, and virtual reality. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of a bending-pressing dual-mode flexible sensor suitable for large deformation according to one embodiment of this application;

[0068] Figure 2 This is a schematic cross-sectional view of a flexible sensing unit according to one embodiment of this application;

[0069] Figure 3 This is a flowchart of a method for fabricating a bending-pressing dual-mode flexible sensor suitable for large deformation according to one embodiment of this application. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0071] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this application.

[0072] The following is in conjunction with the appendix Figures 1 to 3 This application will be described in further detail.

[0073] The first aspect of this application provides a bending-pressing dual-mode flexible sensor suitable for large deformation, comprising: a lateral substrate protective layer, a lateral sensing layer, an encapsulation isolation layer, a longitudinal sensing layer, and a longitudinal substrate protective layer arranged sequentially from top to bottom.

[0074] like Figure 1 As shown, the bending-pressing dual-mode flexible sensor adopts a five-layer composite structure and integrates an orthogonal two-dimensional sensor array network design to achieve collaborative perception of multi-modal information.

[0075] The lateral substrate protective layer is located on the top layer and is used to protect the internal structure of the sensor. This layer is made of elastic materials, such as silicone rubber, polyurethane, and biocompatible hydrogels. These elastic materials can achieve large deformations in a low-resistivity state, ensuring the hardware conditions for multidimensional sensing. In this embodiment, the typical thickness of the lateral substrate protective layer is controlled within the range of 0.5mm-1.5mm.

[0076] The lateral sensing layer contains several first flexible sensing units arranged parallel to each other in the lateral direction. Each first flexible sensing unit has a first wire at both ends, and multiple first wires form a first electrode array. These first flexible sensing units utilize a carbon-based composite material, a mixture of conductive and elastic materials, to construct a conductive network. This network exhibits high sensitivity to lateral deformation and contact force. The sensing units are arranged in a regular array in the lateral direction, providing a foundation for the subsequent formation of an orthogonal two-dimensional sensing array network.

[0077] The encapsulation isolation layer is located between the lateral sensing layer and the longitudinal sensing layer. This layer is also made of elastic materials such as silicone rubber, polyurethane, and hydrogel. The encapsulation isolation layer possesses excellent electrical insulation and structural support properties, effectively isolating the lateral and longitudinal signal channels and preventing interlayer coupling interference.

[0078] The longitudinal sensing layer comprises multiple second flexible sensing units arranged parallel to each other along the longitudinal direction. Second wires are attached to both ends of each second flexible sensing unit, forming a second electrode array. These second flexible sensing units utilize a carbon-based composite material, a mixture of conductive and elastic materials, to construct a conductive network. The first and second flexible sensing units together constitute an orthogonal two-dimensional sensing array network. This array network structure is arranged in a regular grid pattern in both the horizontal and vertical directions, forming an expandable sensing grid with good spatial resolution and position detection capabilities. The horizontal and vertical channels independently acquire signals, arranged orthogonally to each other, supporting cross-location and decoupling of deformation and pressure signals within the two-dimensional plane.

[0079] In a preferred embodiment of this application, the carbon-based composite materials used in the lateral sensing layer and the longitudinal sensing layer can be carbon nanotubes, graphene, or carbon black as conductive fillers, or microstructure conductive elastomer composite materials such as silver nanowires / polydimethylsiloxane (PDMS), carbon spheres / silicone, or liquid metal microdroplets.

[0080] The longitudinal base protective layer, as the bottommost structure, provides overall mechanical support and flexible backing, ensuring the relative position and stability of each functional layer under large deformation conditions. The longitudinal base protective layer uses a low-modulus elastic material, achieving excellent deformation compatibility and structural integrity. In this embodiment, the typical thickness of the longitudinal base protective layer is also controlled within the range of 0.5mm-1.5mm.

[0081] The bending-pressing dual-mode flexible sensor applicable to large deformations in this application is designed and optimized with the following constraints to ensure excellent sensitivity, decoupling capability, and structural stability under complex deformation conditions:

[0082] Flexible sensing unit spacing constraints:

[0083] |d x -d γ |≤β1·min(d x ,d γ )

[0084] Where, d x d represents the spacing between the first flexible sensing units. γ β1 is the spacing between the second flexible sensing units and β2 is the constraint coefficient for the spacing between the flexible sensing units.

[0085] In this embodiment, the spacing constraint coefficient β1 of the flexible sensing unit is preferably 0.1.

[0086] By constraining the spacing between flexible sensing units, it is possible to ensure that the lateral sensing layer and the longitudinal sensing layer have approximately equivalent spatial resolution in two-dimensional space.

[0087] Encapsulation isolation layer thickness constraints:

[0088] β2·d x ≤t≤β3·d x

[0089] β2·d γ ≤t≤β3·d γ

[0090] Where t is the thickness of the encapsulation isolation layer, and β2 and β3 are the constraint coefficients for the thickness of the encapsulation isolation layer;

[0091] In this embodiment, the encapsulation isolation layer thickness constraint coefficient β2 is preferably 0.05, and the encapsulation isolation layer thickness constraint coefficient β3 is preferably 0.1.

[0092] By constraining the thickness of the encapsulation isolation layer, signal crosstalk caused by force coupling between different sensing channels can be prevented, ensuring sufficient isolation buffer thickness while maintaining overall flexibility.

[0093] On-resistance constraint:

[0094] R 下 ≤R≤R 上

[0095]

[0096] Where R is the on-resistance, R下 R is the lower limit of the on-resistance. 上 ρ is the upper limit of the on-resistance, l is the resistivity of the flexible sensing unit material, w is the length of the conductive path, h is the width of the conductive path, and h is the thickness of the conductive path.

[0097] To maintain signal sensitivity and readability, the preferred range for the on-resistance R is 10. 4 Ω≤R≤10 6 Ω.

[0098] Sensor total thickness constraint:

[0099] T≤T 上

[0100] Where T is the total thickness of the sensor, T 上 This represents the upper limit of the total thickness of the sensor.

[0101] In this embodiment, the total thickness T of the sensor is ≤ 2mm. Optimizing the total thickness of the sensor can improve sensitivity, response speed, integration, and flexibility, while reducing power consumption and cost.

[0102] The cross-sectional shape of the flexible sensing unit has a significant impact on its performance. The cross-sectional shape directly or indirectly affects the core performance of the sensor, such as sensitivity, linearity, response range, durability and flexibility, by changing key factors such as stress distribution, strain transfer efficiency, contact area variation law and material utilization.

[0103] In a preferred embodiment of this application, the first flexible sensing unit and the second flexible sensing unit are convex cylindrical in shape. The cross-section is symmetrical overall, the upper and lower boundaries are parallel, and the two middle sides are symmetrical arcs, as shown below. Figure 2 As shown.

[0104] The present application provides a bending-pressing dual-mode flexible sensor suitable for large deformations. The sensor performance factor is formed by combining pressure measurement sensitivity, effective spatial resolution coefficient, shape factor, response time, and channel coupling interference degree, which is used to quantify the sensor performance.

[0105] The sensor performance factor Ф is:

[0106]

[0107] The pressure sensitivity S is:

[0108]

[0109] Where k is the adjustment coefficient and E is the Young's modulus of the flexible sensing unit material;

[0110] Effective spatial resolution coefficient for:

[0111]

[0112] Where λ is the signal attenuation coefficient of the encapsulation isolation layer material, and d is the spacing between the flexible sensing units;

[0113] In this embodiment, the spacing between the first flexible sensing units is equal to the spacing between the second flexible sensing units.

[0114] The shape factor Q is:

[0115]

[0116] Where A is the cross-sectional area of ​​the flexible sensing unit, and P is the perimeter of the flexible sensing unit cross-section;

[0117] The response time τ is:

[0118]

[0119] Where ε0 is the dielectric constant;

[0120] The channel coupling interference level η is:

[0121]

[0122] Among them, Corr(R) x ,R γ R represents the electrical signal correlation between the lateral sensing layer and the longitudinal sensing layer. x R γ These represent the changes in resistance of the transverse and longitudinal sensing layers under the same load conditions, respectively. 'a' is the sparsity adjustment factor, which modulates the interference signal by adjusting the spacing of the sensing layers. The unit of pressure sensitivity is 1 / Pa, and the unit of effective spatial resolution coefficient is 1 / m. 2 The dimension of the shape factor is 1, the unit of response time is s, and the dimension of the channel coupling interference is 1.

[0123] The sensor performance factor is calculated using the formula described above to determine whether the dual-mode flexible sensor meets the performance requirements. This sensor performance factor simultaneously considers the sensor's static performance (sensitivity, resolution), dynamic performance (response time), geometric adaptability (shape factor), and anti-interference capability (channel coupling), enabling a comprehensive quantitative evaluation of sensor performance.

[0124] This application presents a bending-pressing dual-mode flexible sensor suitable for large deformations. The overall design constructs an orthogonal, expandable, and parallelly arranged sensor network in the horizontal and vertical directions, enabling precise perception and localization of external forces (such as deformation and pressure) in a two-dimensional plane. It can simultaneously sense both body deformation and environmental contact, and possesses low resistance and large deformation characteristics, making it suitable for highly flexible and sensitive robot interaction scenarios. Furthermore, each layer undergoes precise design in material selection and structural construction, balancing flexibility, stability, and high sensitivity. The highly modular structure between layers allows for tailoring and expansion according to different application scenarios, exhibiting excellent versatility and system integration capabilities.

[0125] The second aspect of this application provides a method for fabricating a bending-pressing dual-mode flexible sensor suitable for large deformation, used to fabricate the aforementioned bending-pressing dual-mode flexible sensor suitable for large deformation, such as... Figure 3 As shown, the preparation method includes the following steps:

[0126] Step 1: Prepare carbon-based composite materials and form the transverse and longitudinal sensing layers.

[0127] In step one, the first step is to realize the fabrication of the sensing material and the patterning of the sensing layer, specifically including:

[0128] S101. The conductive functional material and the elastic material are mixed in a preset ratio, and after thorough stirring, the mixture is placed in a vacuum chamber to degas, forming a carbon-based composite material.

[0129] S102. Inject the carbon-based composite material into the syringe, and use the dispensing process to extrude multiple first flexible sensing units onto the transfer paper according to the preset trajectory to obtain the transverse sensing layer.

[0130] S103. Inject the carbon-based composite material into the syringe, and use the dispensing process to extrude multiple second flexible sensing units onto the transfer paper according to the preset trajectory to obtain the longitudinal sensing layer.

[0131] S104. When the carbon-based composite material is not cured, after the insulation layer of the wire is removed, the first flexible sensing unit and the second flexible sensing unit are inserted at a preset angle and depth, and the electrode array is formed after static curing.

[0132] In the preparation of the sensing material, conductive functional materials (such as carbon powder) are mixed with elastic materials in a specific ratio and thoroughly stirred. The mixture is then placed in a vacuum chamber for degassing, forming a homogeneous, bubble-free sensing composite material. During the patterning of the sensing layer, the composite material is injected into a syringe, and multiple flexible sensing units are extruded onto transfer paper using a dispensing process. Before the sensing material cures, wires are embedded as electrodes. After removing the insulation layer from the DuPont wires, the exposed wires are inserted into both ends of each flexible sensing unit at a specific angle and depth. After curing, a low-impedance, highly stable conductive path is formed.

[0133] The electrode design employs an embedded connection scheme, constructing a highly efficient electrical contact interface by precisely embedding pre-treated wires into the uncured sensing material matrix. Specifically, on both sides of each sensing path, exposed wires with their insulation precisely stripped are embedded into the sensing material at predetermined angles and depths, forming a directional electrode array. This unique embedded structural design allows the wires and sensing material to form a three-dimensional interlocking interface through intermolecular forces during the curing process, achieving not only stable electrical connection characteristics but also maintaining the structural integrity of the flexible sensing unit. This connection method, through material-structure synergy, effectively improves the conductivity reliability and mechanical durability of the electrode interface.

[0134] Step 2: Spin-coat an elastic material onto the lateral sensing layer and the longitudinal sensing layer to form an encapsulation and isolation layer.

[0135] Step two involves spin-coating and encapsulating the flexible substrate, specifically including:

[0136] S201. Fix the transfer paper with the horizontal sensing layer and the vertical sensing layer onto the spin coating platform;

[0137] S202. A liquid elastic material is uniformly coated on the surface of the transverse sensing layer and the longitudinal sensing layer using a spin coating process, and after static curing, an encapsulation and isolation layer is formed.

[0138] The transfer paper with a transverse or longitudinal sensing layer is fixed on the spin coating platform with the sensing layer facing upwards. Liquid elastic material is evenly covered on the surface, and an ultra-thin encapsulation isolation layer is formed using a low-speed spin coating process. After static curing, the encapsulation isolation layer reaches the predetermined mechanical strength, forming a stable protective structure.

[0139] Step 3: Generate a multi-layer composite structure based on the lateral sensing layer, the encapsulation isolation layer, and the vertical sensing layer.

[0140] Step three involves generating a multi-layered composite structure through multi-layered composite processes, specifically including:

[0141] S301. Fix the transfer paper with the transverse sensing layer onto the spin coating platform;

[0142] S302. A liquid elastic material is uniformly covered on the surface of the transverse sensing layer using a spin coating process. The transfer paper with the longitudinal sensing layer is aligned and bonded with the transfer paper with the transverse sensing layer to form a multi-layer composite structure of transfer paper-transverse sensing layer-encapsulation isolation layer-longitudinal sensing layer-transfer paper.

[0143] S303. Apply a preset pressure to the multi-layer composite structure to remove interlayer air bubbles, and allow it to cure statically.

[0144] The transfer paper with the lateral sensing layer is fixed on the spin coating platform with the sensing layer facing upwards. The liquid elastic material is spin-coated to form an encapsulation film. The transfer paper with the longitudinal sensing layer is precisely aligned and attached with the sensing layer facing downwards to form a multi-layer composite structure. Controllable pressure is applied to remove air bubbles between the layers, and the paper is allowed to stand and cure to ensure a tight bond between the layers and avoid signal interference.

[0145] Step 4: The multi-layer composite structure is encapsulated a second time through a horizontal substrate protective layer and a vertical substrate protective layer to generate a dual-mode flexible sensor.

[0146] Step four involves peeling off the transfer carrier and performing secondary encapsulation, specifically including:

[0147] S401. Fix the multi-layer composite structure to the spin coating platform;

[0148] S402. After softening one side of the multi-layer composite structure by spraying water, peel off the transfer paper with the transverse sensing layer, and use spin coating process to uniformly cover the surface of the transverse sensing layer with liquid elastic material. After static curing, a transverse base protective layer is formed.

[0149] S403. After softening the other side of the multi-layer composite structure by spraying water, peel off the transfer paper with the longitudinal sensing layer, and use a spin coating process to uniformly cover the surface of the longitudinal sensing layer with liquid elastic material. After static curing, a longitudinal base protective layer is formed.

[0150] By spraying water to soften and peel off the transfer paper, the sensing layer is exposed. Liquid elastic material is then spin-coated and cured to form a lateral substrate protective layer and a longitudinal substrate protective layer, ensuring that the sensor is completely isolated from the environment, and finally obtaining a fully encapsulated, highly flexible dual-mode sensor.

[0151] The method for fabricating a flexible sensor with a large deformation bending-pressing dual mode, as described in this application, employs a flexible composite material system and a precision fabrication process, and has the following beneficial effects:

[0152] 1. Dual-mode sensing capability: This flexible sensor can simultaneously sense in-plane deformation and out-of-plane contact, making it suitable for information collection needs in multiple dimensions and scenarios.

[0153] 2. Adaptable to large deformation conditions: Adopting an ultra-thin flexible packaging structure with low overall mechanical impedance, the flexible sensor can still maintain stable operation under large stretching and bending conditions, meeting the integration requirements of high deformation systems such as soft robots.

[0154] 3. High structural regularity and strong array scalability: The flexible sensor adopts an orthogonal two-dimensional grid array design, which has higher arrangement consistency, spatial coverage efficiency and structural scalability compared with common point, snake or spiral sensing structures, which is conducive to large-area deployment and precise contact positioning.

[0155] 4. Advantages of Standardized Manufacturing and Data Mapping: The orthogonal mesh structure possesses spatial regularity, facilitating the implementation of standardized and modular manufacturing processes. Simultaneously, it provides a clear structural correspondence for subsequent signal processing, coordinate mapping, and position recognition algorithms, enhancing the overall system integration and ease of use. Furthermore, through optimized material system combinations, precise control of the single-layer sensing material thickness within the range of 100–900 μm can be achieved, ensuring excellent structural consistency and interface flatness.

[0156] 5. Wide range of applications: This flexible sensor has multi-dimensional sensing capabilities and is suitable for various fields such as medical rehabilitation, human-computer interaction, and virtual reality. It can monitor joint movement status in real time, give robots tactile perception capabilities, and realize gesture recognition and tactile feedback.

[0157] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A flexible sensor with a bending-pressing dual-mode suitable for large deformation, characterized in that, include: The layers arranged from top to bottom are: a lateral substrate protective layer, a lateral sensing layer, an encapsulation isolation layer, a vertical sensing layer, and a vertical substrate protective layer. The lateral sensing layer includes a plurality of first flexible sensing units arranged in parallel along the lateral direction. Each of the first flexible sensing units has a first wire at both ends, and the first wire forms a first electrode array. The longitudinal sensing layer includes a plurality of second flexible sensing units arranged in parallel along the longitudinal direction. The two ends of the second flexible sensing units are provided with second wires, and the second wires form a second electrode array. The first flexible sensing unit and the second flexible sensing unit are arranged in a grid pattern to form an orthogonal two-dimensional sensing array network.

2. The bending-pressing dual-mode flexible sensor suitable for large deformation according to claim 1, characterized in that, The lateral substrate protective layer, the encapsulation isolation layer, and the longitudinal substrate protective layer are all made of elastic materials, which are one of silicone rubber, polyurethane, and hydrogel.

3. The bending-pressing dual-mode flexible sensor suitable for large deformation according to claim 1, characterized in that, Both the first flexible sensing unit and the second flexible sensing unit are made of carbon-based composite material, which is a mixture of conductive functional material and elastic material.

4. The bending-pressing dual-mode flexible sensor suitable for large deformation according to claim 1, characterized in that, The parameters of the dual-mode flexible sensor satisfy the following constraints: Flexible sensing unit spacing constraints: |d x -d γ |≤β1·min(d x ,d γ ) Where, d x d represents the spacing between the first flexible sensing units. γ β1 is the spacing between the second flexible sensing units and β2 is the constraint coefficient for the spacing between the flexible sensing units. Encapsulation isolation layer thickness constraints: β2·d x ≤t≤β3·d x β2·d γ ≤t≤β3·d γ Where t is the thickness of the encapsulation isolation layer, and β2 and β3 are the constraint coefficients for the thickness of the encapsulation isolation layer; On-resistance constraint: R 下 ≤R≤R 上 Where R is the on-resistance, R 下 R is the lower limit of the on-resistance. 上 ρ is the upper limit of the on-resistance, l is the resistivity of the flexible sensing unit material, w is the length of the conductive path, h is the width of the conductive path, and h is the thickness of the conductive path. Sensor total thickness constraint: T≤T 上 Where T is the total thickness of the sensor, T 上 This represents the upper limit of the total thickness of the sensor.

5. The bending-pressing dual-mode flexible sensor suitable for large deformation according to claim 4, characterized in that, The performance factor Ф of the sensor is calculated to determine whether the dual-mode flexible sensor meets the performance requirements. The pressure sensitivity S is: Where k is the adjustment coefficient and E is the Young's modulus of the flexible sensing unit material; Effective spatial resolution coefficient for: Where λ is the signal attenuation coefficient of the encapsulation isolation layer material, and d is the spacing between the flexible sensing units; The shape factor Q is: Where A is the cross-sectional area of ​​the flexible sensing unit, and P is the perimeter of the flexible sensing unit cross-section; The response time τ is: Where ε0 is the dielectric constant; The channel coupling interference level η is: Among them, Corr(R) x ,R γ R represents the electrical signal correlation between the lateral sensing layer and the longitudinal sensing layer. x R represents the change in resistance of the lateral sensing layer. γ denoted as the change in resistance of the longitudinal sensing layer, and 'a' as the arrangement sparsity adjustment factor.

6. A method for fabricating a bending-pressing dual-mode flexible sensor suitable for large deformation, used to fabricate the bending-pressing dual-mode flexible sensor suitable for large deformation as described in any one of claims 1 to 5, characterized in that, include: Step 1: Prepare carbon-based composite materials and form the transverse and longitudinal sensing layers; Step 2: Spin-coating an elastic material onto the lateral sensing layer and the longitudinal sensing layer to form an encapsulation and isolation layer; Step 3: Generate a multi-layer composite structure based on the lateral sensing layer, the encapsulation isolation layer, and the vertical sensing layer; Step 4: The multi-layer composite structure is encapsulated a second time through a horizontal substrate protective layer and a vertical substrate protective layer to generate a dual-mode flexible sensor.

7. The method for fabricating a bending-pressing dual-mode flexible sensor suitable for large deformation according to claim 6, characterized in that, In step one, a carbon-based composite material is prepared, and the transverse and longitudinal sensing layers are formed, including: S101. The conductive functional material and the elastic material are mixed in a preset ratio, and after thorough stirring, the mixture is placed in a vacuum chamber to degas, forming a carbon-based composite material. S102. Inject the carbon-based composite material into the syringe, and use the dispensing process to extrude multiple first flexible sensing units onto the transfer paper according to the preset trajectory to obtain the transverse sensing layer. S103. Inject the carbon-based composite material into the syringe, and use the dispensing process to extrude multiple second flexible sensing units onto the transfer paper according to the preset trajectory to obtain the longitudinal sensing layer. S104. When the carbon-based composite material is not cured, after the insulation layer of the wire is removed, the first flexible sensing unit and the second flexible sensing unit are inserted at a preset angle and depth, and the electrode array is formed after static curing.

8. The method for fabricating a bending-pressing dual-mode flexible sensor suitable for large deformation according to claim 6, characterized in that, In step two, an elastic material is spin-coated onto the lateral sensing layer and the longitudinal sensing layer to form an encapsulation and isolation layer, including: S201. Fix the transfer paper with the horizontal sensing layer and the vertical sensing layer onto the spin coating platform; S202. A liquid elastic material is uniformly coated on the surface of the transverse sensing layer and the longitudinal sensing layer using a spin coating process, and after static curing, an encapsulation and isolation layer is formed.

9. The method for fabricating a bending-pressing dual-mode flexible sensor suitable for large deformation according to claim 6, characterized in that, In step three, a multi-layer composite structure is generated based on the lateral sensing layer, the encapsulation isolation layer, and the vertical sensing layer, including: S301. Fix the transfer paper with the transverse sensing layer onto the spin coating platform; S302. A liquid elastic material is uniformly covered on the surface of the transverse sensing layer using a spin coating process. The transfer paper with the longitudinal sensing layer is aligned and bonded with the transfer paper with the transverse sensing layer to form a multi-layer composite structure of transfer paper-transverse sensing layer-encapsulation isolation layer-longitudinal sensing layer-transfer paper. S303. Apply a preset pressure to the multi-layer composite structure to remove interlayer air bubbles, and allow it to cure statically.

10. The method for fabricating a bending-pressing dual-mode flexible sensor suitable for large deformation according to claim 6, characterized in that, In step four, the multi-layer composite structure is encapsulated a second time using a lateral substrate protective layer and a longitudinal substrate protective layer to generate a dual-mode flexible sensor, including: S401. Fix the multi-layer composite structure to the spin coating platform; S402. After softening one side of the multi-layer composite structure by spraying water, peel off the transfer paper with the transverse sensing layer, and use spin coating process to uniformly cover the surface of the transverse sensing layer with liquid elastic material. After static curing, a transverse base protective layer is formed. S403. After softening the other side of the multi-layer composite structure by spraying water, peel off the transfer paper with the longitudinal sensing layer, and use a spin coating process to uniformly cover the surface of the longitudinal sensing layer with liquid elastic material. After static curing, a longitudinal base protective layer is formed.

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