Laminated three-dimensional pressure sensing equipment

Abstract

The utility model discloses laminated three-dimensional pressure sensing equipment, which comprises a force sensitive part, insulating parts and electrodes, the force sensitive part and the insulating parts are sheet-shaped, the force sensitive part is formed by stacking at least two flexible piezoresistive conducting layers, the insulating parts are arranged between every two flexible piezoresistive conducting layers, and the electrodes are arranged on the insulating parts. The insulating part is made of an insulating elastic deformable material, a plurality of electrodes are arranged on the periphery of each flexible piezoresistive conducting layer, and the electrodes are used for leading out resistance distribution data in each flexible piezoresistive conducting layer through wires. Based on this, the laminated three-dimensional pressure sensing equipment has the characteristics that the structure is simple, the whole body is made of a full-flexible material, only electrodes and wires need to be arranged on the periphery, no wire is needed inside, good attachment can be achieved according to the shape of a curved surface, a flat touch interface can be achieved, and the pressure sensing equipment is convenient to use. And the three-dimensional pressure measuring range is very wide, and the sensitivity is higher, so that the sensitivity and the measuring range of three-dimensional force measurement are improved.

Description

TECHNICAL FIELD

[0001] The embodiment of the utility model relates to but is not limited to the technical field of pressure sensing, in particular to a laminated three-dimensional pressure sensing device. BACKGROUND

[0002] In the current thriving development of emerging technology fields such as the Internet of Things, smart home and furniture, humanoid and flexible robots, the demand for pressure measurement technology of human-computer interaction interface is increasingly urgent. These industries expect the device interface to accurately capture the pressure changes of the user or the environment interface to achieve a more natural, safe and intelligent interaction experience. For example, if a humanoid robot has electronic skin, i.e. a tactile function similar to human skin, it will greatly improve its interaction ability with the environment and humans. Existing flexible tactile sensors, such as linear piezoresistive and array tactile sensors, all have many drawbacks, including complex manufacturing process and wiring, high cost, and relatively single sensing function. Moreover, when detecting touch position, force intensity and shape, such sensors often cannot achieve multi-dimensional pressure detection, so the application range is also limited.

[0003] The traditional pressure monitoring technology is to use a pressure sensor matrix to measure in an expanded manner, which has very significant limitations. Since each sensor unit needs to be connected by independent wires, the number of wires of the sensor matrix is extremely large, which not only makes the device more complex and the cost higher, but also negatively affects the flexibility, stretchability and ability to adhere to complex surfaces of the device. If every sensor unit in the pressure sensor matrix is upgraded to a three-dimensional pressure sensor, the number of wires for each sensor will increase from two to six, eight or even more, and the complexity and cost of the device will be even more serious, greatly limiting the flexibility and application scenarios of the device. SUMMARY

[0004] The following is a summary of the subject matter described in detail in this document. This summary is not intended to limit the scope of protection of the claims.

[0005] The embodiment of the utility model provides a laminated three-dimensional pressure sensing device, has simple structure, the whole body adopts full flexible material's characteristic, only need to arrange electrode and wire in the periphery, inside does not need any wire, and can realize good adhesion to the curved surface shape, can realize pure flat touch interface, and has very wide three-dimensional pressure measurement range and higher sensitivity, thereby improving the sensitivity and range of three-dimensional force measurement.

[0006] This utility model provides a stacked three-dimensional pressure sensing device, including: a force-sensitive part, an insulating part, and electrodes. The force-sensitive part and the insulating part are sheet-like. The force-sensitive part is composed of at least two layers of flexible piezoresistive conductive layers stacked together. An insulating part is disposed between every two layers of the flexible piezoresistive conductive layers. The insulating part is made of an insulating, elastic, deformable material. Multiple electrodes are arranged around each layer of the flexible piezoresistive conductive layer. The electrodes are used to lead out the resistance distribution data inside each layer of the flexible piezoresistive conductive layer through wires, so that the back-end circuit equipment can read the resistance distribution data of each layer of the flexible piezoresistive conductive layer in real time by impedance scanning imaging. The resistance distribution data inside the conductive layer is used to calculate the pressure distribution data at each position on the surface of each flexible piezoresistive conductive layer at each time. Then, the pressure distribution data of each layer is calculated to obtain the three-dimensional pressure distribution information on the surface of the stacked three-dimensional pressure sensing device. The resistance distribution data includes normal pressure data and shear pressure data. The normal pressure data of all pressure-bearing positions on the surface of the flexible piezoresistive conductive layer is obtained from the pressure distribution data of the first layer of the flexible piezoresistive conductive layer. The shear pressure data is obtained by differential calculation of the pressure distribution data of multiple layers of the flexible piezoresistive conductive layer.

[0007] In some embodiments, the force-sensitive portion is made of flexible conductive material sheets, films, or fabrics, and each layer of the flexible piezoresistive conductive layer is a solid planar layer structure, or a planar network structure, or a portion of the planar network structure contains holes.

[0008] In some embodiments, the insulating portion is made of an elastic and flexible insulating material, the insulating portion is in sheet-like or flat shape, and the thickness of the insulating portion is maintained on the order of millimeters or micrometers.

[0009] In some embodiments, the electrodes are also arranged at a predetermined density in a predetermined region of each layer of the flexible piezoresistive conductive layer.

[0010] In some embodiments, the flexible piezoresistive conductive layer is a conductive composite material, or a conductor or semiconductor material rich in conductive ions, or a conductive fiber assembly with piezoresistive properties, or an elastomer containing an intrinsically conductive polymer.

[0011] In some embodiments, the insulating portion is a polyurethane film or a silicone insulating sheet.

[0012] In some embodiments, the electrode is a coating or plating of a good conductor, or a micron- or nano-structured material, or a carbon-based conductive material, or a metal-plated fiber material, or an intrinsically conductive polymer, or a liquid metal.

[0013] In some embodiments, the insulating portion is placed between the two flexible piezoresistive conductive layers by bonding, wherein the bonding method includes any one of hot pressing, adhesive bonding, and roll pressing.

[0014] In some embodiments, the surface of the force-sensitive portion is covered with an encapsulation layer, the encapsulation material of which is a flexible polymer elastomer with low elastic modulus.

[0015] In some embodiments, the force-sensitive portion and the insulating portion are fabricated using a multi-layer or three-dimensional weaving method to create an upper flexible piezoresistive conductive layer, a lower flexible piezoresistive conductive layer, and an intermediate insulating layer with piezoresistive effect. The layers of the upper flexible piezoresistive conductive layer, the lower flexible piezoresistive conductive layer, and the intermediate insulating layer are connected by yarns. Wires are embroidered around the periphery of the upper and lower flexible piezoresistive conductive layers as required. The wires are any one of stainless steel fibers, silver-plated nylon yarn, copper-nickel-plated nylon yarn, and micron-sized pure copper filaments. Alternatively, the force-sensitive portion and the insulating portion are sewn together, with the upper flexible piezoresistive conductive layer, the lower flexible piezoresistive conductive layer, and the intermediate insulating layer stitched together, and silver-plated nylon threads sewn at designated positions around each flexible piezoresistive conductive layer.

[0016] This utility model provides a stacked three-dimensional pressure sensing device, comprising: a force-sensitive part, an insulating part, and electrodes. The force-sensitive part and the insulating part are sheet-like. The force-sensitive part is composed of at least two layers of flexible piezoresistive conductive layers stacked together. An insulating part is disposed between every two layers of flexible piezoresistive conductive layers. The insulating part is made of an insulating, elastic, deformable material. Multiple electrodes are arranged around each layer of flexible piezoresistive conductive layers. The electrodes are used to lead out the resistance distribution data inside each layer of flexible piezoresistive conductive layers through wires, so that the back-end circuit equipment can read the resistance distribution data inside each layer of flexible piezoresistive conductive layers in real time by resistive impedance scanning imaging. The pressure distribution data of each position on the surface of each layer of flexible piezoresistive conductive layers at each time is calculated based on the resistance distribution data. Then, the pressure distribution data of each layer is calculated to obtain the three-dimensional pressure distribution information on the surface of the stacked three-dimensional pressure sensing device. The resistance distribution data includes normal pressure data and shear pressure data. The normal pressure data of all pressure-bearing positions on the surface of the flexible piezoresistive conductive layers is obtained from the pressure distribution data of the first layer of flexible piezoresistive conductive layers. The shear pressure data is obtained by differential calculation of the pressure distribution data of multiple layers of flexible piezoresistive conductive layers. This invention employs at least two layers of flexible piezoresistive conductive material to form the force-sensitive component. This conductive material exhibits piezoresistive characteristics, meaning its resistance changes systematically under compression and tension. Therefore, this conductive material is formed into a sheet shape to construct planar data of pressure distribution. By stacking two or more sheet-like conductive materials, with a sheet-like insulating elastic material between each pair of conductive materials, a layered three-dimensional pressure sensing structure is formed. Multiple electrodes are arranged around each layer of conductive material, and these electrodes are used to connect wires to extract signals. By using impedance scanning imaging to read the resistance distribution data within each layer of flexible conductive material in real time, the pressure distribution at each location on each force-sensitive plane can be determined. Then, the normal pressure at all pressing positions is primarily obtained through the first layer of piezoresistive conductive material, while the shear pressure data is obtained through differential calculations of the pressure data from multiple layers of piezoresistive conductive materials. This achieves a fully flexible, multi-point simultaneous detection layered three-dimensional pressure touch sensing device with no internal electrodes or only partial electrodes, based on impedance scanning imaging—functionally equivalent to a three-dimensional pressure sensor matrix. Based on this, the stacked three-dimensional pressure sensing device of this utility model has the advantages of simple structure and all-flexible material. It only needs to arrange electrodes and wires around the perimeter, and no wires are needed inside. It can also achieve good fit for curved surfaces, realize a flat touch interface, and has a very wide three-dimensional pressure measurement range and higher sensitivity, thereby improving the sensitivity and range of three-dimensional force measurement.

[0017] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0018] The accompanying drawings are provided to further understand the technical solution of this utility model and constitute a part of the specification. They are used together with the embodiments of this utility model to explain the technical solution of this utility model, and do not constitute a limitation on the technical solution of this utility model.

[0019] Figure 1A A top view of a stacked three-dimensional pressure sensing device provided in an embodiment of this utility model;

[0020] Figure 1B for Figure 1A A schematic diagram of the cross-sectional structure along the dashed line in the top view;

[0021] Figure 2 A cross-sectional structural diagram of a stacked three-dimensional pressure sensing device provided in another embodiment of this utility model;

[0022] Figure 3 A cross-sectional structural diagram of a stacked three-dimensional pressure sensing device provided in another embodiment of this utility model;

[0023] Figure 4A A cross-sectional structural diagram of a stacked three-dimensional pressure sensing device provided in another embodiment of this utility model;

[0024] Figure 4B for Figure 4A The diagram shows the structure of the insulating layer.

[0025] Figure 5 A cross-sectional structural diagram of a stacked three-dimensional pressure sensing device provided in another embodiment of this utility model. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0027] It should be understood that in the description of the embodiments of this utility model, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first," "second," etc., are used in the description, they are only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0028] With the booming development of emerging technologies such as the Internet of Things, smart homes and furniture, and humanoid and flexible robots, the demand for pressure measurement technology for human-computer interaction interfaces is becoming increasingly urgent. These industries expect device interfaces to accurately capture pressure changes of users or the environment to achieve a more natural, safe, and intelligent interactive experience. For example, if humanoid robots could possess electronic skin, i.e., tactile functions similar to human skin, it would greatly enhance their ability to interact with the environment and humans. Existing flexible tactile sensors, such as linear piezoresistive and array-type tactile sensors, have many drawbacks: complex manufacturing processes and wiring, high costs, and relatively limited sensing functions. Furthermore, when detecting touch location, force intensity, and shape, these sensors often cannot achieve multi-dimensional pressure detection, thus limiting their application scope.

[0029] Traditional pressure monitoring technology uses a pressure sensor matrix for measurement, which has significant limitations. Because each sensor unit requires an independent wire connection, the number of wires in the sensor matrix is ​​extremely large. This not only increases the complexity and cost of the equipment but also negatively impacts its flexibility, stretchability, and ability to conform to complex surfaces. If each sensor unit in the pressure sensor matrix were upgraded to a three-dimensional pressure sensor, the number of wires per sensor would surge from two to six, eight, or even more, further exacerbating the complexity and cost issues and severely limiting the equipment's flexibility and application scenarios.

[0030] To address the aforementioned technical problems, this utility model provides a stacked three-dimensional pressure sensing device, comprising: a force-sensitive part, an insulating part, and electrodes. The force-sensitive part and the insulating part are sheet-like. The force-sensitive part is composed of at least two layers of flexible piezoresistive conductive layers stacked together. An insulating part is disposed between each two layers of flexible piezoresistive conductive layers. The insulating part is made of an insulating, elastic, deformable material. Multiple electrodes are arranged around each layer of flexible piezoresistive conductive layer. The electrodes are used to extract the resistance distribution data inside each layer of flexible piezoresistive conductive layer through wires, so that the back-end circuitry can read the resistance distribution data of each layer in real time using impedance scanning imaging. The resistance distribution data inside the flexible piezoresistive conductive layer is used to calculate the pressure distribution data at each position on the surface of each flexible piezoresistive conductive layer at each time. Then, the pressure distribution data of each layer is calculated to obtain the three-dimensional pressure distribution information on the surface of the stacked three-dimensional pressure sensing device. The resistance distribution data includes normal pressure data and shear pressure data. The normal pressure data of all pressure-bearing positions on the surface of the flexible piezoresistive conductive layer is obtained from the pressure distribution data of the first flexible piezoresistive conductive layer, and the shear pressure data is obtained through differential calculation of the pressure distribution data of multiple flexible piezoresistive conductive layers. This embodiment of the invention uses at least two layers of flexible piezoresistive conductive material to form the force-sensitive part. This conductive material has piezoresistive characteristics, meaning its resistance changes regularly when subjected to compression or tension. Therefore, this conductive material is made into a sheet to construct planar data of the pressure distribution. By stacking two or more sheet-like conductive materials, with a sheet-like insulating elastic material added between each two layers, a stacked three-dimensional pressure sensing structure can be formed. Multiple electrodes are arranged around each layer of conductive material, and these electrodes are used to connect wires to lead out signals. By employing electrical impedance tomography (EIT) to read the resistance distribution data within each layer of flexible conductive material in real time, the pressure distribution at each location on each force-sensitive plane can be determined. Then, the normal pressure at all pressing positions is primarily obtained through the first layer of piezoresistive conductive material, while the shear pressure data is obtained through differential calculations of the pressure data from multiple layers of piezoresistive conductive material. This results in a fully flexible, multi-point simultaneous detection, stacked three-dimensional pressure touch sensing device with no internal electrodes or only partial electrodes, functionally equivalent to a three-dimensional pressure sensor matrix. Based on this, the stacked three-dimensional pressure sensing device of this invention has the advantages of simple structure, using entirely flexible materials, requiring only electrodes and wires around the perimeter (no internal wires), and achieving good fit to curved surfaces, enabling a completely flat touch interface. It also possesses a very wide three-dimensional pressure measurement range and higher sensitivity, thereby improving the sensitivity and range of three-dimensional force measurement.

[0031] The stacked three-dimensional pressure sensing device of this invention consists of three parts: a force-sensitive part, an insulating part, and an electrode.

[0032] It is understandable that the force-sensitive part contains at least two flexible piezoresistive conductive layers. The flexible piezoresistive conductive layers are made of piezoresistive conductive materials, and electrodes are arranged around the perimeter of each flexible piezoresistive conductive layer. The resistance distribution of each flexible piezoresistive conductive layer is monitored in real time by means of electrical impedance imaging, so as to calculate the pressure distribution information of each position on the surface of the flexible piezoresistive conductive layer of different sensing layers of the device at each time. Then, the data of each flexible piezoresistive conductive layer are calculated to obtain the three-dimensional pressure distribution information of the entire device.

[0033] It is understood that the force-sensitive part and the insulating part of this utility model are sheet-like, which can realistically simulate the flat state of the human skin surface. Therefore, it can achieve good fit for curved shapes and realize a completely flat touch interface.

[0034] Understandably, this invention measures three-dimensional force using at least two layers of piezoresistive conductive material. When shear force is applied, because it operates horizontally, each layer experiences horizontal displacement at the point of stress. The upper layer exhibits the largest displacement, followed by the second layer, and so on. This is because the elastic material of a certain thickness disperses surface stress. Therefore, the lower the layer, the larger the projected area of ​​the transmitted three-dimensional force, the more the projected stress attenuates, and the slower the projected horizontal displacement. This results in pressure misalignment in each layer. Consequently, the mapping of three-dimensional force across different layers of piezoresistive material produces different two-dimensional topological patterns. By comparing the differences in piezoresistive data distribution between different layers, the magnitude and direction of the three-dimensional pressure can be deduced. This method is somewhat similar to computed tomography (CT) scanning, where the mapping of three-dimensional force information on each layer is captured layer by layer, and then the data from all layers are merged and calculated to reconstruct the entire three-dimensional pressure distribution data.

[0035] It should be noted that for the calibration of stacked 3D pressure sensing devices, initial measurements may have deviations due to individual material differences and slight variations in assembly processes. By using a standard pressure generator to apply known pressure to the device from multiple pressure angles and at different pressure amplitudes, collecting and comparing the device's output data, and precisely adjusting the backend circuit parameters, the stacked 3D pressure sensing device can accurately reflect the actual pressure situation.

[0036] Understandably, the force-sensitive component is made of flexible conductive material sheets, films, or fabrics. Each layer of conductive material presents a solid planar structure, or a planar network structure, meaning that some areas contain pores. These flexible conductive materials possess a characteristic: when subjected to pressure, the resistance at the corresponding location changes; this is the piezoresistive characteristic. Furthermore, it doesn't matter if it's not a conventionally understood piezoresistive material, as long as the resistance at the pressured location exhibits a regular and repeatable change under pressure.

[0037] Understandably, the insulating part is made of an insulating material with excellent elasticity and flexibility. This insulating part is sheet-like / flat in shape, and its thickness is preferably maintained on the order of millimeters or micrometers to ensure effective isolation without taking up too much space. Its texture is uniform, and it can also be a planar network structure, meaning that some areas contain holes, but it is necessary to ensure that each area can stably perform its insulating function, preventing accidental conduction between the conductive materials of different force-sensitive layers. The sheet-like insulating material can be tightly bonded to the flexible conductive materials above and below. During various deformations such as pressure, bending, and torsion, the insulating material will not easily break, thus building a solid insulating barrier for the stable operation of the entire sensing device. Therefore, whether in static placement or dynamic usage scenarios, the insulating part can consistently maintain good insulation performance.

[0038] Understandably, electrodes can be evenly distributed around each force-sensitive layer, allowing for both equal spacing and adjustable density based on resolution and accuracy requirements at different locations. In addition to arranging electrodes around the perimeter, electrodes can be selectively added at various locations beneath the force-sensitive material, significantly improving the positional and pressure accuracy of the sensor measurements. Within a consistent back-end processing circuit and algorithm framework, the electrode layout acts as a "precision regulating valve." Increased electrode quantity and optimized distribution lead to richer information acquired through impedance imaging, simultaneously improving the accuracy of normal pressure measurement, shear force resolution, and position recognition.

[0039] Understandably, conductive composite materials are preferred for the force-sensitive portion. To enhance the piezoresistive properties, the resistance of such conductive materials should ideally be within the semiconductor range. Preferred materials for the force-sensitive portion include piezoresistive rubber, graphite / silicone composites, and multi-arm carbon nanotube / polyurethane composites. Other materials that can be selected include gallium-indium alloys, or conductive / semiconductor materials with a certain degree of fluidity, such as gels and liquids rich in conductive ions. Conductive fiber assemblies with piezoresistive properties can also be used as force-sensitive materials, such as pure cotton knitted fabrics with graphene and carbon nanotubes attached to their surface, or spandex warp-knitted mesh completely coated with carbon black / polyurethane composites using screen printing technology. Additionally, elastomers containing intrinsically conductive polymers, such as composite films of polypyrrole and polyurethane, are also acceptable. In short, any sheet-like material that is elastic and continuously conductive, whether porous or solid, will meet the usage requirements of the force-sensitive portion of this invention, as long as the resistance at the pressure point changes repeatably and regularly under pressure. The force-sensitive part can be designed as a flat planar structure or with protrusions, depending on the requirements.

[0040] Understandably, the insulation materials prioritize materials with excellent flexibility and superior insulation performance. Common examples include polyurethane films or silicone insulating sheets. These materials are soft, elastic, and highly malleable, easily adapting to different device structures to ensure a tight fit and prevent conductive parts from "crossing over." The insulation materials are often in thin sheet form, with the thickness precisely controlled to prevent leakage and short circuits without hindering the compact assembly of the entire device. They seamlessly connect with adjacent force-sensitive parts, ensuring consistent insulation performance and durability regardless of daily minor vibrations or frequent deformations during long-term use.

[0041] It is understandable that the materials of the electrode part can be coatings or platings of good conductors such as gold, silver, and copper, or micron- or nano-structured materials (such as silver nanowires / silicone composites, or silver powder particles / epoxy resin composites), or carbon-based conductive materials (such as carbon fibers), or metal-plated fiber materials, or intrinsically conductive polymers (such as poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid), or liquid metals (such as gallium-indium alloys).

[0042] Understandably, placing an insulating flexible film between two layers of flexible conductive material allows for accurate bonding without wrinkles or air bubbles, achieved through methods such as hot pressing, bonding, and rolling. The electrode layer can be placed before or after bonding. High-precision processes like screen printing and chemical vapor deposition are used to attach electrode material to designated electrode sites, depending on the location requirements. Alternatively, simpler processes like applying silver paste resin or embroidering electrodes with silver-plated nylon yarn can be employed. After electrode attachment, connecting wires are used to connect to the downstream circuitry. For some special designs, if additional mechanical conduction reinforcement structures are needed, similar functionality can be achieved using external accessories, even without a separate conductive section. For example, moderately hard and shape-fitting silicone or rubber blocks can be glued to corresponding sites on the force-sensitive surface using a dispensing machine; or a custom 3D-printed structure can be attached to key stress points beneath the force-sensitive material to facilitate more efficient pressure transmission to the force-sensitive part. After assembly, the electrodes and wires are connected.

[0043] Understandably, an encapsulation layer can be optionally applied to the upper and lower surfaces of the device, especially to the force-sensitive parts and critical areas that may come into contact with pressure sources. A flexible polymer elastomer with a low elastic modulus is preferred, as it protects the internal flexible conductive materials and insulating film from moisture and dust, and also promotes uniform pressure distribution upon pressure contact, preventing localized stress concentrations that could damage the device, ensuring stable operation and maintaining measurement accuracy. The encapsulation layer can also be used to smooth out the uneven surface of the force-sensitive layer.

[0044] Understandably, the triaxial elasticity of the force-sensitive and insulating components lays the foundation for the device's adaptability. Excellent triaxial elasticity allows the device to overcome planar limitations, conforming to spherical and irregular curved surfaces, such as the joints of intelligent prostheses. Even with stretching and deformation, after calibration, the device still captures complete and accurate three-dimensional pressure information, greatly enriching its application scenarios. The pressure-sensitive properties of the force-sensitive material are key to its sensitivity; under the same conditions, the more significant the piezoresistive effect, the more sensitive the device is to detecting minute pressures. Simultaneously, the size and stiffness of the force-sensitive component synergistically affect the measurement range and sensitivity. While a larger size combined with high stiffness results in stronger stress concentration and increased sensitivity, it can limit the measurable upper limit of force. Variations in the number, distribution, and density of auxiliary transmission structures with different layouts also alter the pressure transmission effect to varying degrees, thereby adjusting the range and accuracy of three-dimensional force measurement.

[0045] It is understood that, in addition to using the polymer film or sheet materials proposed in the above claims for fabrication, the layered three-dimensional pressure sensing device can also be fabricated entirely or partially using fiber materials and textile processes. For example, multi-layer weaving and three-dimensional weaving can be used to fabricate an upper pressure-sensitive layer, a lower pressure-sensitive layer, and an intermediate insulating layer with piezoresistive effect in one step. The layers are connected by yarns, and finally, wires are embroidered around the upper and lower pressure-sensitive layers as required, preferably stainless steel fibers, silver-plated nylon yarns, copper-nickel-plated nylon yarns, and micron-sized pure copper filaments. Alternatively, a sewing method can be used to sew the upper pressure-resistant fabric layer, the lower pressure-resistant fabric layer, and the intermediate insulating fabric layer together, and silver-plated nylon threads are sewn at designated positions around each pressure-resistant fabric layer.

[0046] Based on this, the stacked three-dimensional pressure sensing device of this invention is mainly composed of elastic materials and is divided into three parts according to function: a force-sensitive part, an insulating part, and electrodes. The force-sensitive part is constructed using a flexible conductive material, which exhibits piezoresistive characteristics, meaning its resistance changes regularly when subjected to compression or stretching. Therefore, this conductive material can be made into a sheet (or thin film) to construct planar data of pressure distribution. By stacking two or more layers of sheet-like conductive material, with a sheet-like insulating elastic material added between each two layers, a stacked three-dimensional pressure sensing structure is formed. Multiple electrodes are arranged around each layer of conductive material, and these electrodes are used to connect wires to extract signals. By using impedance scanning imaging to read the resistance distribution data inside each layer of flexible conductive material in real time, the pressure distribution at each location on each force-sensitive plane can be determined. Then, the normal pressure of all pressing positions is mainly obtained through the first layer of piezoresistive conductive material, while the shear pressure data is obtained through differential calculation of the pressure data of multiple layers of piezoresistive conductive material. This realizes a fully flexible, multi-point simultaneous detection stacked three-dimensional pressure touch sensing device with no internal electrodes or only partial electrodes, based on impedance scanning imaging, which is functionally equivalent to a three-dimensional pressure sensor matrix.

[0047] In summary, this utility model provides a three-dimensional pressure sensing device that is simple in structure, low in cost, easy to process, made of fully flexible material, requires only electrodes and wires to be arranged around the periphery, can be without any internal wires, and has good conformability to curved surfaces. It adopts a multi-layered structure with a flat surface, can accommodate measurement ranges of high, medium, and low pressure, and can detect three-dimensional pressure with high sensitivity.

[0048] The embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0049] Example 1

[0050] Please see Figure 1A and Figure 1BThis embodiment provides a layered flexible three-dimensional pressure sensing device, comprising three parts: a force-sensitive part 1, an insulating part 2, and an electrode part 3. The force-sensitive part 1 is made of silicone rubber filled with graphene and carbon nanotubes, with conductive particles imparting piezoresistive properties. When a part is compressed, its resistance changes systematically. These two layers of flexible conductive material are crucial for the entire measurement; under external three-dimensional multi-point pressure, the resistance changes at different locations carry the pressure information at those locations, providing fundamental data support for subsequent calculations of the three-dimensional pressure distribution. The insulating part 2 uses a flexible and insulating silicone material, preferably in sheet form with a thickness in the millimeter range. Through processes such as hot pressing, vacuuming, and rolling, it is securely placed between the two layers of force-sensitive part 1, ensuring a tight fit, eliminating gaps and air bubbles, and effectively preventing accidental conduction between the two conductive materials. Under various deformation conditions such as pressure and bending, the insulating part 2 maintains a stable insulation effect, ensuring that the measurement is not interfered with. The electrode part 3 is made of a composite material of silver nanowires and silicone. First, an ethanol dispersion of silver nanowires is applied to the electrode position. After the ethanol evaporates, a small amount of silicone is added to complete the molding. Thanks to the silicone rubber component, it can bond tightly to the force-sensitive part 1, and the silver nanowires also achieve a reliable electrical connection with the force-sensitive part 1. The electrodes are evenly distributed around the device. The electrode spacing can be equidistant to meet basic measurement requirements, and the electrode density can be flexibly adjusted according to the accuracy requirements of different positions.

[0051] During operation, due to the piezoresistive characteristics of the force-sensitive part 1, pressure causes different resistance changes in the upper and lower conductive materials. By sequentially applying current to the electrodes around the device and simultaneously measuring the voltage distribution of the other electrodes—that is, using impedance scanning imaging technology—the real-time resistance distribution of the two force-sensitive materials can be read. By calculating the difference between the resistance distribution data of the two materials, the three-dimensional pressure distribution at various locations on the plane of the device can be accurately deduced.

[0052] This device only arranges electrodes around the perimeter, significantly reducing the number of wires required compared to traditional three-dimensional pressure sensor matrices. It also avoids the reliance on stretchable wire technology when manufacturing integral stretchable flexible devices, making it highly practical. Furthermore, this embodiment achieves real-time three-dimensional pressure monitoring at multiple points in a plane. Compared to the limited position recognition function of inductive or capacitive pressure touchpads and the single normal pressure measurement function of conventional impedance scanning imaging, it can provide the shear force distribution at multiple points, demonstrating significant innovation.

[0053] (1) The first variant of Example 1:

[0054] See Figure 2Based on the aforementioned device architecture, this embodiment also includes an optional configuration: an encapsulation layer 4. A casting process is used to uniformly cover the entire surface of the device with a layer of silicone, and another layer of silicone is applied to the lower surface. This treatment results in a smooth and even surface, providing insulation, aesthetics, and protection. Regarding material selection, silicone material of the same type as the force-sensitive layer 1 is preferred, but a silicone material with a lower elastic modulus than the force-sensitive layer 1 can also be preferred as the encapsulation layer 4. In this way, when external pressure is applied to the encapsulated device surface, the normal pressure and lateral shear force at each location can be transmitted efficiently and accurately without obstruction, maximizing the effectiveness and stability of pressure transmission and maintaining the accuracy of device measurements.

[0055] (2) The second variant of Example 1:

[0056] Reference Figure 2 To achieve weak pressure measurement, the force-sensitive part 1 can also utilize a composite structure of polyurethane foam and ionic liquid. Polyurethane foam has a unique three-dimensional porous structure with abundant and interconnected pores, providing smooth channels for ion movement. The ionic liquid fills these pores and is rich in various ions (such as the anions and cations in imidazole ionic liquids), possessing excellent conductivity. When subjected to external pressure, the pores of the polyurethane foam deform, compressing or stretching the ionic liquid within, causing changes in the ion distribution density and movement path, thus inducing a significant change in resistance. This composite structure has a low overall elastic modulus and is highly sensitive to weak pressure, accurately capturing even the slightest external force and converting it into a measurable resistance signal. In conjunction with the force-sensitive part 1, the insulation part 2 also uses a polyurethane foam structure, and the encapsulation layer 4 also uses polyurethane foam. This layered device can achieve three-dimensional weak pressure measurement.

[0057] This variant of the stacked flexible device, due to its unique structure and materials, demonstrates significant advantages in the field of micro-pressure detection. It is particularly suitable for scenarios with stringent requirements for sensing weak pressure, such as micro-force monitoring during the assembly of high-precision electronic components and biomechanical research of biological cells, thus expanding the application scope of flexible three-dimensional pressure sensing devices.

[0058] Example 2

[0059] Please see Figure 3This embodiment provides a stacked flexible three-dimensional pressure sensing device containing three force-sensitive layers. The device comprises three parts: a force-sensitive part 1, an insulating part 2, and an electrode part 3. Unlike Embodiment 1, the force-sensitive part 1 in this embodiment has three layers, which can be referred to as the upper force-sensitive part 1, the middle force-sensitive part 1, and the lower force-sensitive part 1 from top to bottom. The insulating part 2 has two layers, referred to as the first insulating layer and the second insulating layer from top to bottom. In this embodiment, the thickness and elastic modulus of the first and second insulating layers can be preferably adjusted. For example, the elastic modulus of the first insulating layer is 1 / 5 of the elastic modulus of the second insulating layer, and the thickness of the first and second insulating layers are the same. In this way, the shear force applied to the surface of the upper force-sensitive part 1 will more easily cause slippage of the upper force-sensitive part 1, while it will be relatively less likely to cause slippage of the middle force-sensitive part 1. Therefore, the difference in tangential pressure distribution data between the upper and middle force-sensitive sections 1 will be larger, while the difference between the middle and lower force-sensitive sections 1 will be smaller. This has the advantage that the upper and middle force-sensitive sections are more capable of measuring minute shear forces, while the middle and lower force-sensitive sections are more capable of measuring larger shear forces. This functional partitioning effectively increases the overall shear force measurement range of the device, enabling it to be sensitive to both minute and large pressure and shear forces simultaneously. Of course, to further expand the pressure measurement range of the device, designs with more force-sensitive layers are also possible, all within the scope of this patent. It should also be noted that the material of each force-sensitive section can be adjusted as needed, and it is not necessary to use the same material and proportions exclusively. For example, for measuring minute pressures, a more sensitive force-sensitive section 1 is required, while for measuring larger pressures, a force-sensitive section 1 with a relatively lower sensitivity level is needed.

[0060] Example 3

[0061] Please refer to Figure 4. This embodiment demonstrates a multi-point supported, stacked, fully flexible three-dimensional pressure sensing device. Unlike Embodiment 1, the intermediate insulating layer 12 employs a discontinuous lattice arrangement. As shown in Figure 4, each insulating unit is a cylinder, connecting the upper and lower pressure-sensitive layers. Compared to the original material, the discontinuous lattice insulating arrangement effectively reduces the overall stiffness of the insulating layer, thereby significantly increasing the misalignment of the upper pressure-sensitive layer under shear force, thus achieving higher shear force measurement sensitivity. Each unit of the insulator can be a cylinder or other three-dimensional shapes, such as a thin cylinder, frustum, triangular pyramid, cone, truncated triangular pyramid, truncated frustum, etc. In addition to adjusting the pressure measurement sensitivity and working range through parameters such as thickness and elastic modulus as shown in Embodiment 2, the shape parameters of the insulating layer can be designed to further improve the misalignment between layers under shear force, thereby enhancing the force measurement sensitivity.

[0062] Example 4

[0063] The embodiments described above all illustrate solid structures; however, non-solid materials can also be used. A typical example is the structure of textiles. Please refer to [link / reference]. Figure 5 The force-sensitive part 101 is made of carbon black / polyurethane fiber, and the insulation part 102 is made of polyurethane fiber. The upper and lower layers of the force-sensitive part 101 and the insulation part 102 are woven in one piece using a three-dimensional textile weaving method. The electrode part 103 is made of silver-plated nylon yarn embroidered around the force-sensitive part 101 at designated positions. The carbon black / polyurethane composite material itself has certain inherent piezoresistive properties, so this fabric can be used to measure pressure by scanning impedance. More importantly, since all raw materials are woven with elastic yarn, the resulting layered device has multi-directional stretchability and large deformation capacity. Therefore, in addition to measuring multi-point three-dimensional pressure on flat surfaces, this textile device can also be wrapped around curved surfaces with different curvatures, such as wrapping around the robot's arm, palm, and fingers, giving the robot a completely skin-friendly three-dimensional pressure measurement surface.

[0064] Based on this, compared with the prior art, the stacked three-dimensional pressure sensing device of this utility model has at least the following beneficial effects:

[0065] (1) A flat equipment surface, high sensitivity, and a wide pressure measurement range can all be achieved simultaneously. This utility model adopts a multi-layer stacked structure, which can not only take into account the measurement range of large, medium, and small pressures, but also improve the sensitivity of pressure measurement through the parameters of the insulation layer. This utility model provides a stacked pressure sensing device that can realize the intermediate detection part of the equipment without wires, and the intermediate detection part can be an elastomer with high tensile properties, with a flat surface, high sensitivity to detect three-dimensional pressure, and can cover large, medium, and small pressures.

[0066] (2) Three-dimensional force: This invention can realize multi-functional detection of the touch position, the magnitude and direction of the pressure at each touch position, and the overall shape of the touch pressure, which greatly improves the sensor's sensing capability. In particular, the sensing of three-dimensional force can provide richer information compared to the sensing of pure normal pressure.

[0067] (3) Simple structure and process: Compared with the pressure sensor matrix, this utility model adopts an integrated structure, which does not require the design of complex internal microstructures and wiring, thus reducing the manufacturing difficulty and cost.

[0068] (4) Flexibility and stretchability: The sensor material is low in cost and flexible, possessing natural flexibility and stretchability without the need for stretchable wires. It can easily cover the surface of various irregular three-dimensional objects for all-round tactile coverage and sensing, improving the applicability and practicality of the sensor.

[0069] (5) Textile characteristics: When a flexible three-dimensional force sensing device is made of textile materials, it also has the advantages of textiles and apparel products, including skin-friendly, comfortable, breathable, porous, lightweight, machine washable, dryable, etc., so it can be perfectly combined with various textiles and apparel products.

[0070] The above is a detailed description of the preferred embodiments of the present utility model. However, the present utility model is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present utility model.

Claims

1. A stacked three-dimensional pressure sensing device, characterized in that, include: The device comprises a force-sensitive portion, an insulating portion, and electrodes. The force-sensitive portion and the insulating portion are sheet-shaped. The force-sensitive portion is composed of at least two layers of flexible piezoresistive conductive layers stacked together. An insulating portion is disposed between every two layers of the flexible piezoresistive conductive layers. The insulating portion is made of an insulating, elastically deformable material. Multiple electrodes are arranged around the perimeter of each layer of the flexible piezoresistive conductive layer. The electrodes are used to extract the resistance distribution data inside each layer of the flexible piezoresistive conductive layer via wires, so that the back-end circuitry can read the resistance distribution data inside each layer of the flexible piezoresistive conductive layer in real time using impedance scanning imaging. The pressure distribution data at each position on the surface of each layer of the flexible piezoresistive conductive layer at each time is calculated based on the resistance distribution data. Then, the pressure distribution data of each layer is calculated to obtain the three-dimensional pressure distribution information on the surface of the stacked three-dimensional pressure sensing device. The resistance distribution data includes normal pressure data and shear pressure data. The normal pressure data of all pressure-bearing positions on the surface of the flexible piezoresistive conductive layer is obtained from the pressure distribution data of the first layer of the flexible piezoresistive conductive layer. The shear pressure data is obtained by differential calculation of the pressure distribution data of multiple layers of the flexible piezoresistive conductive layer.

2. The stacked three-dimensional pressure sensing device according to claim 1, characterized in that, The force-sensitive part is made of flexible conductive material sheets, films or fabrics. Each layer of the flexible piezoresistive conductive layer is a solid planar layer structure, or a planar network structure, or a planar network structure in which some areas contain holes.

3. The stacked three-dimensional pressure sensing device according to claim 1, characterized in that, The insulating part is made of an elastic and flexible insulating material. The insulating part is in sheet-like or flat shape, and the thickness of the insulating part is maintained on the order of millimeters or micrometers.

4. The stacked three-dimensional pressure sensing device according to claim 1, characterized in that, The electrodes are also arranged at a preset density in a preset area of ​​each layer of the flexible piezoresistive conductive layer.

5. The stacked three-dimensional pressure sensing device according to claim 1, characterized in that, The flexible piezoresistive conductive layer is made of conductive composite material, or is a conductor or semiconductor material rich in conductive ions, or is an aggregate of conductive fibers with piezoresistive properties, or is an elastomer containing intrinsically conductive polymers.

6. The stacked three-dimensional pressure sensing device according to claim 1, characterized in that, The insulating part is made of polyurethane film or silicone insulating sheet.

7. The stacked three-dimensional pressure sensing device according to claim 1, characterized in that, The electrode is made of a coating or plating of a good conductor, or a micron- or nano-structured material, or a carbon-based conductive material, or a metal-plated fiber material, or an intrinsically conductive polymer, or a liquid metal.

8. The stacked three-dimensional pressure sensing device according to claim 1, characterized in that, The insulating portion is placed between the two flexible piezoresistive conductive layers by bonding, wherein the bonding method includes any one of hot pressing, adhesive bonding, and roll pressing.

9. The stacked three-dimensional pressure sensing device according to claim 1, characterized in that, The surface of the force-sensitive part is covered with an encapsulation layer, and the encapsulation material of the encapsulation layer is a flexible polymer elastomer with low elastic modulus.

10. The stacked three-dimensional pressure sensing device according to claim 1, characterized in that, The force-sensitive part and the insulating part are fabricated using a multi-layer or three-dimensional weaving method to create an upper flexible piezoresistive conductive layer, a lower flexible piezoresistive conductive layer, and an intermediate insulating layer with piezoresistive effect. The layers of the upper flexible piezoresistive conductive layer, the lower flexible piezoresistive conductive layer, and the intermediate insulating layer are connected by yarns. Wires are embroidered around the periphery of the upper and lower flexible piezoresistive conductive layers as required. The wires are any one of stainless steel fibers, silver-plated nylon yarn, copper-nickel-plated nylon yarn, and micron-sized pure copper filaments. Alternatively, the force-sensitive part and the insulating part are sewn together, with the upper flexible piezoresistive conductive layer, the lower flexible piezoresistive conductive layer, and the intermediate insulating layer sewn together, and silver-plated nylon threads sewn at designated positions around each flexible piezoresistive conductive layer.

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