Sensing unit, electronic skin structure and sensing unit manufacturing method

Abstract

The invention discloses a sensing unit, an electronic skin structure and a sensing unit manufacturing method, and relates to the technical field of robot sensors, the sensing unit comprises a flexible substrate and a pressure sensing assembly, and the flexible substrate is provided with a plurality of tabulate deformation beams arranged around the central peripheral side of the flexible substrate. The pressure sensing assembly comprises a plurality of first grid wires and a plurality of second grid wires, the plurality of first grid wires and the plurality of second grid wires are arranged on the plurality of deformation beams around the center of the flexible substrate, the first grid wires and the second grid wires located on the same deformation beam are arranged at intervals, and the first grid wires are closer to the center of the flexible substrate than the second grid wires. The deformation beam is in a flat plate shape and is not provided with any groove structure, the problem that the structural rigidity is weakened due to arrangement of grooves is avoided, plastic deformation or breakage is not prone to occurring, meanwhile, distribution of induction areas is optimized through interval arrangement of the first grid wires and the second grid wires, and the sensitivity and precision of pressure induction are improved.

Description

Technical Field

[0001] This invention relates to the field of robot sensor technology, specifically to a sensing unit, an electronic skin structure, and a method for manufacturing the sensing unit. Background Technology

[0002] Electronic skin is the primary organ for robots to respond to external stimuli such as pressure, touch, vibration, and temperature. Research on electronic skin is particularly crucial in the field of humanoid robots. The high precision, high resolution, and high sensitivity requirements of robotic dexterity hands render traditional sensor manufacturing techniques unsuitable; therefore, the use of MEMS (Micro-Electro-Mechanical Systems) technology is essential. Piezoresistive sensors are the most commonly used, offering simple manufacturing processes and stable sensor performance.

[0003] Prior art, disclosed in publication CN118482841A, discloses a pressure sensor and its fabrication method. The pressure sensor includes a silicon strain gauge diaphragm, which has a crossbeam, a strain diaphragm, and a back cavity formed sequentially from top to bottom. The crossbeam divides the silicon strain gauge diaphragm into four symmetrically arranged hollow portions, each hollow portion being petal-shaped. A piezoresistive resistor is provided at each of the four ends of the crossbeam, forming a Wheatstone bridge between them. A groove is provided on the crossbeam. In this disclosed pressure sensor, the groove on the crossbeam of the strain diaphragm increases the deformation deflection of the crossbeam, thereby increasing the concentrated stress of the piezoresistive resistors at the four ends of the crossbeam, and thus improving the sensitivity of the pressure sensor.

[0004] However, this existing pressure sensor has shortcomings. For example, it increases the sensitivity of the pressure sensor by adding grooves to the crossbeam to increase the deformation and deflection of the crossbeam. But adding grooves also weakens the rigidity of the crossbeam, causing it to deflect more under the same pressure, making it more prone to plastic deformation or fracture. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a sensing unit, an electronic skin structure, and a method for manufacturing the sensing unit. This invention solves the technical problem in the prior art where the pressure sensor of the robot skin weakens the rigidity of the cross beam by setting grooves on the cross beam, causing it to generate greater deflection under the same pressure, which makes it prone to plastic deformation or fracture.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a sensing unit, comprising: A flexible substrate having multiple flat, deformable beams arranged around its center; and The pressure sensing component includes a plurality of first grid wires and a plurality of second grid wires. The plurality of first grid wires and the plurality of second grid wires are arranged around the center of the flexible substrate on a plurality of deformation beams. The first grid wires and second grid wires located on the same deformation beam are arranged at intervals, and the first grid wires are closer to the center of the flexible substrate than the second grid wires.

[0007] In some embodiments, on the same deformable beam, the first grid wire encloses a region, and the second grid wire is located in the region.

[0008] In some embodiments, the end of the first grid wire near the center of the flexible substrate is continuously bent to form a plurality of first sensing grids.

[0009] In some embodiments, the end of the second grid wire near the center of the flexible substrate is continuously bent to form a plurality of second sensing grids, and the number of the second sensing grids is not less than the number of the first sensing grids.

[0010] In some embodiments, the ends of a plurality of second grid wires are connected sequentially to form a Wheatstone bridge.

[0011] In some embodiments, the flexible substrate has four hollowed-out slots arranged in a matrix to form a first deformation beam and a second deformation beam, the first deformation beam and the second deformation beam being arranged perpendicularly to each other and the intersection point being located at the center of the flexible substrate.

[0012] In some embodiments, the sensing unit further includes an arcuate protrusion located at the center of the flexible substrate, the arcuate protrusion protruding from the surface of the flexible substrate.

[0013] In some embodiments, the sensing unit further includes a temperature sensing element disposed at the corner of the flexible substrate.

[0014] Secondly, the present invention also provides an electronic skin structure, including a plurality of the above-mentioned sensing units, wherein the plurality of sensing units are arranged in an array, the flexible substrates of adjacent sensing units are interconnected, the first grid wires are interconnected, and the second grid wires are interconnected.

[0015] Thirdly, the present invention also provides a method for manufacturing a sensing unit, for manufacturing the above-mentioned sensing unit, characterized in that the manufacturing method includes the following steps: Prepare a silicon wafer, etch grooves with a depth of 100-200μm and a width of 500μm into the silicon wafer to form multiple deformation beams, then fill the grooves with the first layer of PI adhesive and polish it to form a flat flexible substrate. A first dielectric layer, a temperature sensing layer, and a second dielectric layer are sequentially deposited on the deformable beam of the flexible substrate. Dry etching is used to preserve only the temperature-sensitive island located in the middle of the four pressure-sensitive layers, and then an insulating PI adhesive layer is applied for isolation. A pressure-sensing layer is deposited around the perimeter using a negative adhesive peeling process, covered with a second PI adhesive for encapsulation, and then a metal solder plate is made by separate wiring. After grinding the back side to the bottom of the groove, the entire device is peeled off in acetone solution to obtain an independent PI device. UV adhesive protrusions are formed by applying adhesive to the center of multiple deformable beams and curing at low temperature. Finally, the PI device is encapsulated in a silicone film in a sandwich manner to complete the flexible electronic skin sensor.

[0016] Compared with existing technologies, the sensing unit provided by this invention employs a flexible substrate and multiple flat deformation beams arranged around its center. These deformation beams are flat and without any grooves, avoiding the problem of weakened structural rigidity caused by grooves. Therefore, under pressure, the deformation beams maintain high structural stability and are less prone to plastic deformation or fracture, significantly improving the sensor's lifespan and reliability. Furthermore, multiple first and second grid wires are arranged around the center of the flexible substrate on each deformation beam, with the first and second grid wires on the same deformation beam spaced apart. The first grid wires are closer to the center of the flexible substrate. This grid wire arrangement effectively captures pressure changes without weakening structural rigidity. Simultaneously, the spaced arrangement of the first and second grid wires optimizes the distribution of the sensing area, improving the sensitivity of pressure sensing. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a sensing unit provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a Wheatstone bridge formed by multiple second grid wires provided in an embodiment of the present invention; Figure 3 yes Figure 1 The diagram shows the structure of the sensing unit under stress in the embodiment shown. Figure 4 This is a schematic diagram of the electronic skin structure provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the layout of multiple electronic skin structures in a robot hand according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the structural state changes during the fabrication of the sensing unit using the sensing unit fabrication method of this invention; Figure 7 This is a flowchart illustrating the method for manufacturing a sensing unit provided in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention 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 merely illustrative and not intended to limit the invention.

[0019] To address the technical problem that existing robotic skin pressure sensors weaken the rigidity of the crossbeam by creating grooves, causing it to deflect more under the same pressure and making it prone to plastic deformation or fracture, this invention provides a sensing unit, an electronic skin structure, and a method for manufacturing the sensing unit, which can improve the rigidity and sensitivity of the crossbeam without creating grooves.

[0020] It should be noted that the sensing unit described in this invention is used in, but not limited to, robots. For ease of explanation, this invention will only use the application of the sensing unit in a robot as an example. The principle of the sensing unit applied in other types of devices is essentially the same as that applied in a robot, and will not be described in detail here.

[0021] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a sensing unit in one embodiment of the present invention. The sensing unit 1 includes a flexible substrate 11 and a pressure sensing component 12. The flexible substrate 11 has a plurality of flat deformation beams 111 arranged around its center. The pressure sensing component 12 includes a plurality of first grid wires 121 and a plurality of second grid wires 122. The plurality of first grid wires 121 and the plurality of second grid wires 122 are all arranged around the center of the flexible substrate 11 on the plurality of deformation beams 111. The first grid wires 121 and the second grid wires 122 located on the same deformation beam 111 are arranged at intervals, and the first grid wires 121 are closer to the center of the flexible substrate 11 than the second grid wires 122.

[0022] In this embodiment, the flexible substrate 11 is the basic structure of the entire sensing unit. The flexible substrate 11 has multiple flat deformation beams 111 arranged around its center. These deformation beams 111 are the core structure of the sensing unit, used to sense changes in external pressure. Unlike the prior art method of increasing deflection by creating grooves in the deformation beams 111, the deformation beams 111 of the present invention are flat and have no groove structure, thereby avoiding the problem of weakening the structural rigidity of the deformation beams 111 by creating grooves. The deformation beams 111 of the present invention can maintain high structural stability when subjected to pressure, are not prone to plastic deformation or fracture, and significantly improve the service life and reliability of the sensor.

[0023] In addition, existing pressure sensors are usually based on rigid substrates, which limits their application in some irregular structures and the range of pressure sensors. The flexible substrate 11 provided in this embodiment has a certain deformation capability, which can be applied to some irregular structures and expands the range of pressure sensors.

[0024] The flexible substrate 11 can be made of polyimide (PI) material, which has good flexibility, mechanical strength, and high-temperature resistance, making it ideal for fabricating flexible sensors. The number of deformable beams 111 can be adjusted according to actual needs, for example, it can be set to four, six or more, to meet different sensitivity and accuracy requirements.

[0025] Each deformation beam 111 is provided with a first grid wire 121 and a second grid wire 122. The first grid wire 121 and the second grid wire 122 on the same deformation beam 111 are arranged at intervals, and the first grid wire 121 is closer to the center of the flexible substrate 11 than the second grid wire 122. This embodiment can effectively capture pressure changes without weakening the structural rigidity of the deformation beam 111. At the same time, the distribution of the sensing area is optimized by arranging the first grid wire 121 and the second grid wire 122 at intervals, thereby improving the sensitivity of pressure sensing.

[0026] In one embodiment, please refer to Figure 1 On the same deformable beam 111, a first grid wire 121 encloses a region 123, and a second grid wire 122 is located within the region 123. In this embodiment, the first grid wire 121 encloses the second grid wire 122, allowing the first and second grid wires 121 to work together better, further improving the sensitivity and accuracy of pressure sensing. The first and second grid wires 121 and 122 can be made of piezoresistive material. When the deformable beam deforms, the resistance value of the grid wires changes, thereby achieving pressure sensing.

[0027] In one embodiment, please refer to Figure 1 The first grid wire 121 is continuously bent at its end near the center of the flexible substrate 11 to form multiple first sensing grids. In this embodiment, multiple first sensing grids 121a are formed by continuously bending the end of the first grid wire 121 near the center of the flexible substrate 11. These first sensing grids 121a can further increase the area of ​​the grid wire deformation region, thereby further improving the pressure sensing sensitivity. The more numerous and denser the first sensing grids 121a, the higher the pressure sensing sensitivity of the part of the first grid wire 121 near the center of the flexible substrate 11. Specifically, the design of the first sensing grids 121a allows the grid wire to more sensitively capture changes in resistance value when the deformation beam 111 undergoes slight deformation.

[0028] In one embodiment, please refer to Figure 1 The second grid wire 122, near the center of the flexible substrate 11, is continuously bent to form multiple second sensing grids 122a, and the number of second sensing grids 122a is less than the number of first sensing grids 121a. This embodiment uses this structural configuration to enable the second grid wire 122 to form an effective sensing interaction with the first grid wire 121 without adding excessive complexity, further optimizing the distribution of the sensing area. In this embodiment, the number of second sensing grids 122a is not less than the number of first sensing grids 121a. Since the second sensing grids 122a are located in areas of low strain, as many second sensing grids 122a as possible are provided to ensure sufficient sensing accuracy and expand the sensor's range.

[0029] In one embodiment, please refer to Figure 1 The flexible substrate 11 has four matrix-arranged perforated slots 112 to form first deformation beams 111a and second deformation beams 111b. There are two first deformation beams 111a and two deformation beams 111b. The two first deformation beams 111a and the two second deformation beams 111b are located on the same straight line, and they are arranged perpendicularly to each other, with the intersection point located at the center of the flexible substrate 11. This structural configuration not only improves the rigidity of the deformation beams 111 but also optimizes the distribution of pressure sensing, making it more uniform and stable under pressure. Specifically, the matrix-arranged deformation beams 111 can better disperse pressure, avoid local overload, and thus improve the overall performance of the sensor. Two first metal welding plates 113 are provided at the middle position of each of the four sides of the flexible substrate 11, and the two ends of the first grid wire 121 on each deformation beam 111 are connected to the two nearest first metal welding plates 113.

[0030] Further, please refer to Figure 1 and Figure 2 Based on the previous embodiment, the ends of multiple second grid wires 122 on the two first deformation beams 111a and the two second deformation beams 111b are sequentially connected to form a Wheatstone bridge. In this embodiment, second metal welding plates 114 are provided at the four apex corners of the flexible substrate 11, and the ends of the four second grid wires 122 on the four deformation beams are connected to the four second metal welding plates 114 to form a Wheatstone bridge. By connecting all the first metal welding plates 113 and the second metal welding plates 114 to a feedback system, the pressure exerted on the deformation beams 111 can be fed back through the feedback system.

[0031] The Wheatstone bridge is a classic resistance measurement circuit. This connection method effectively improves the accuracy and stability of pressure sensing, while facilitating signal acquisition and processing. When external pressure is applied to the deformable beam 111, the resistance value of the second grid wire 122 changes. Through the balance principle of the Wheatstone bridge, the change in resistance value can be accurately measured, thereby achieving high-precision pressure measurement.

[0032] The working principle of this embodiment is based on the strain effect and the piezoresistive effect based on the Wheatstone bridge structure. When the deformation beam 111 is deformed by external force, the resistance values ​​of the first grid wire 121 and the second grid wire 122 on the deformation beam 111 change, causing the Wheatstone bridge to become unbalanced. Under the excitation of DC voltage, the pressure signal is converted into an electrical signal.

[0033] The strain effect can be expressed as: In the formula, R is the resistance of the second grid wire; L is the grid wire length; A is the cross-sectional area of ​​the second grid wire; ρ is the resistivity of the metal thin film; and μ is the Poisson's ratio of the metal thin film. For axial strain.

[0034] Ideally, for the four second grid wires 122 arranged around the center of the flexible substrate 11, when the resistances of the four second grid wires 122 are equal and no external force is applied to the second grid wires 122, the output voltage is zero. When the deformation beam 111 deforms, one pair of deformation beams 111 is compressed, causing an increase in resistance, while the other pair of deformation beams 111 is stretched, causing a decrease in resistance. Therefore, the output voltage is: In the formula, U in This is the input voltage, and R1, R2, R3, and R4 are the resistance values ​​of the four second grid wires 122, respectively.

[0035] This invention employs a full-bridge Wheatstone bridge structure design. The full bridge achieves temperature compensation through a circuit structure composed of four deformation beams 111. That is, when the temperature changes, all deformation beams 111 generate thermal strain synchronously, causing the resistance value to change. Since the four deformation beams 111 have the same coefficient of thermal expansion, their resistance changes in the bridge cancel each other out. Ultimately, the output voltage of the bridge only reflects the actual mechanical strain, thereby eliminating temperature-induced interference.

[0036] In one embodiment, please refer to Figure 1 The sensing unit 1 also includes an arc-shaped protrusion 13 located at the center of the flexible substrate 11, protruding from the surface of the flexible substrate 11. In this embodiment, the arc-shaped protrusion 13, fabricated using a dispensing machine at the center of the flexible substrate 11, helps to increase the sensitivity of the sensor. Figure 3It is known that when the cross-beam structure formed by the four deformation beams 111 is subjected to external loads, the deformation of the cross-beam structure is most pronounced near the center of the arc-shaped protrusion 13 and in the middle of the deformation beams 111. Therefore, setting multiple sets of grid wires in the cross-beam structure is beneficial to improving the stress monitoring sensitivity of the cross-beam structure. When the force reaches a certain threshold, the strain of the first grid wire 121 near the center of the arc-shaped protrusion 13 will reach its upper limit. At this time, the second set of grid wires 122 in the middle of the beam can still deform and still play a monitoring role, which will greatly expand the measurement range of the sensor. The arc-shaped protrusion 13 can be formed by UV adhesive or other suitable materials through dispensing and curing processes.

[0037] In one embodiment, the sensing unit 1 further includes a temperature sensing element 14, which is disposed at a corner of the flexible substrate 11. The pressure stress at the corner of the flexible substrate 11 is minimal, making it less prone to deformation and thus having less impact on the temperature sensing element 14. Please refer to... Figure 4 A temperature sensing element 14 is disposed at the connection center of the four sensing units 1, and multiple temperature sensing elements 14 are arranged in an array in this manner. In this embodiment, the temperature sensing element 14 can be made of a thermistor material, implemented by depositing a temperature sensing layer on a flexible substrate 11. The placement of the temperature sensing element 14 enables real-time monitoring of the ambient temperature, thereby providing more accurate reference data for pressure sensing and further improving the overall performance of the sensor. For example, when the temperature changes, the temperature sensing element can provide real-time feedback on the temperature change, and the pressure sensing results can be corrected through a compensation algorithm, thereby improving the accuracy of the measurement.

[0038] Secondly, please refer to Figure 4 and Figure 5 The present invention also provides an electronic skin structure 2, which includes a plurality of the aforementioned sensing units 1. The plurality of sensing units 1 are arranged in an array, with the flexible substrates 11 of adjacent sensing units 1 interconnected, the first grid wires 121 interconnected, and the second grid wires 122 interconnected. This array arrangement allows the electronic skin structure 2 to cover a larger area while maintaining high pressure sensing sensitivity and accuracy, making it suitable for applications such as robots that require large-area flexible pressure sensing.

[0039] In practical implementation, the electronic skin structure can employ flexible printed circuit (FPC) technology to connect multiple sensing units 1 together via conductive lines, forming a complete sensor network. Each sensing unit 1 can operate independently or be centrally processed through signal processing circuitry, thereby achieving real-time monitoring of pressure distribution over a large area. For example, in the application of robotic dexterity hands, the electronic skin structure 2 can cover the entire palm and finger surfaces, enabling high-precision sensing of contact forces, thus improving the robot's operational accuracy and flexibility.

[0040] To further increase the sensing area, multiple electronic skin structures 2 can be set on the robot's palm 3. The multiple electronic skin structures 2 can be kept at a certain distance to cover the entire palm 3 of the robot as much as possible, so that the entire palm 3 of the robot has high pressure sensitivity.

[0041] Thirdly, please refer to Figure 6 and Figure 7 The present invention also provides a method for manufacturing a sensing unit, which is used to manufacture the above-mentioned sensing unit. The manufacturing method mainly includes the following steps: 1. Prepare silicon wafers and etch deformed beams 111 Prepare a silicon wafer 4. The thickness of wafer 4 can be selected according to actual needs; for example, a wafer with a thickness of 500μm can be selected. Using photolithography and etching processes, grooves 112 with a depth of 100-200μm and a width of 500μm are etched into the silicon wafer 4, thereby forming multiple deformation beams 111. The etching process can be dry etching (such as plasma etching) or wet etching (such as chemical etching), the specific choice depending on actual needs. Dry etching has high precision and controllability, making it suitable for the fabrication of high-precision deformation beams.

[0042] 2. Fill with PI adhesive and form a flexible substrate 11 A first layer of polyimide (PI) adhesive 5 is uniformly coated onto the surface of the silicon wafer 4, filling the etched grooves 112. The first layer of polyimide (PI) adhesive 5 possesses good flexibility and mechanical properties, providing stable support for subsequent structures. After coating, the first layer of polyimide (PI) adhesive 5 is cured, for example, using a thermosetting process at 200-300℃ for more than 2 hours, forming a flat flexible substrate 11. The cured flexible substrate 11 has a flat surface without grooves, effectively avoiding the problem of weakened structural rigidity due to grooves.

[0043] 3. Deposition medium layer and temperature sensing layer A first dielectric layer 61, a temperature-sensing layer 62, and a second dielectric layer 63 are sequentially deposited on the deformable beam 111 of the flexible substrate. The first dielectric layer 61 and the second dielectric layer 63 can be made of silicon nitride, silicon dioxide, or other suitable insulating materials, and are deposited using a chemical vapor deposition (CVD) process. The temperature-sensing layer 62 can be made of a thermistor material, such as manganese oxide (MnO) or nickel oxide (NiO), and is formed as a thin temperature-sensing layer on the deformable beam using a sputtering or evaporation deposition process. Subsequently, a dry etching process is used to retain only the temperature-sensitive islands located between the multiple pressure-sensitive layers, thereby achieving the temperature sensing function.

[0044] 4. Deposit the pressure sensing layer and etch the grid wires. A pressure-sensing layer 8 is deposited on the periphery of the flexible substrate 11 using a negative resist peeling process. The pressure-sensing layer 8 can be made of a piezoresistive material, such as doped polysilicon or metal oxide. After deposition, a second layer of PI adhesive 71 is applied, and the first gate wire 121, the second gate wire 122, the first metal bonding plate 113, and the second metal bonding plate 114 are etched using photolithography and etching processes. The etching process can be dry etching or wet etching, depending on the material and process requirements. The etched gate wire structure should have good conductivity and mechanical stability, and be able to effectively sense pressure changes in the deformed beam 111.

[0045] 5. Backside grinding and peeling The back side of silicon wafer 4 is ground down to the bottom of groove 112. The grinding depth should be precisely controlled to ensure the structural integrity of the deformable beam and the flatness of the flexible substrate. After grinding, silicon wafer 4 is immersed in an acetone solution for complete peeling. The acetone solution can dissolve the adhesion layer between silicon wafer 4 and flexible substrate 11, thereby achieving complete peeling of flexible substrate 11. The peeled flexible substrate 11 has good flexibility and mechanical properties, making it suitable for subsequent encapsulation processing.

[0046] 6. Form an arc-shaped protrusion and encapsulate it. UV adhesive is applied to the center of multiple deformable beams 111 to form UV-cured protrusions, which are then cured at low temperature to form arc-shaped protrusions 13. The height of the arc-shaped protrusions 13 can be adjusted according to actual needs, for example, it can be set to 0.5-1.0 mm. The cured arc-shaped protrusions 13 can further optimize the pressure distribution, making the pressure sensing in the central area more sensitive. Finally, the flexible substrate 11 is sandwiched within a silicone film to complete the fabrication of the flexible electronic skin sensor. The encapsulated sensor has good waterproof and dustproof performance and can adapt to complex usage environments.

[0047] Through the above-described fabrication method, this invention enables the creation of a flexible sensing unit with high sensitivity, high precision, and high reliability, suitable for applications requiring flexible pressure sensing, such as robotics. This fabrication method combines advanced micro-nano processing technology with the application of flexible materials, exhibiting high process feasibility and production efficiency, and meeting the needs of large-scale production.

[0048] To better understand this invention, the following is combined with... Figures 1 to 7 The technical solution of the present invention will be described in detail below: This invention successfully solves the problem of weakened rigidity of the deformation beam due to grooves in existing technologies by employing innovative sensing unit design, electronic skin structure layout, and efficient manufacturing processes, significantly improving the structural stability and lifespan of the sensor. Through a flat deformation beam design and optimized grid layout, this invention not only improves the sensitivity and accuracy of pressure sensing but also further enhances the sensor's overall performance through temperature sensing elements and arc-shaped protrusions. Furthermore, the electronic skin structure provided by this invention enables large-area flexible pressure sensing, making it suitable for complex applications such as robotics. Combined with advanced micro-nano fabrication technology, the manufacturing method of this invention has high process feasibility and production efficiency, meeting the needs of large-scale production. Overall, this invention has significant application value and broad market prospects in the field of robot sensor technology, providing strong technical support for the future development of intelligent robot technology.

[0049] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A sensing unit, characterized in that, include: A flexible substrate with multiple flat, deformable beams arranged around its center; and The pressure sensing component includes a plurality of first grid wires and a plurality of second grid wires. The plurality of first grid wires and the plurality of second grid wires are arranged around the center of the flexible substrate on a plurality of deformation beams. The first grid wires and second grid wires located on the same deformation beam are arranged at intervals, and the first grid wires are closer to the center of the flexible substrate than the second grid wires.

2. The sensing unit according to claim 1, characterized in that, On the same deformable beam, the first grid wire forms an enclosing area, and the second grid wire is located in the enclosing area.

3. The sensing unit according to claim 1, characterized in that, The first grid wire is continuously bent at its end near the center of the flexible substrate to form multiple first sensing grids.

4. The sensing unit according to claim 3, characterized in that, The second grid wire is continuously bent at its end near the center of the flexible substrate to form a plurality of second sensing grids, the number of the second sensing grids being no less than the number of the first sensing grids.

5. The sensing unit according to claim 1, characterized in that, The ends of multiple second grid wires are connected sequentially to form a Wheatstone bridge.

6. The sensing unit according to claim 1, characterized in that, The flexible substrate has four hollowed-out grooves arranged in a matrix to form a first deformation beam and a second deformation beam. The first deformation beam and the second deformation beam are arranged perpendicularly to each other and the intersection point is located at the center of the flexible substrate.

7. The sensing unit according to claim 1, characterized in that, The sensing unit also includes an arc-shaped protrusion located at the center of the flexible substrate, the arc-shaped protrusion protruding from the surface of the flexible substrate.

8. The sensing unit according to claim 1, characterized in that, The sensing unit also includes a temperature sensing element, which is located at the corner of the flexible substrate.

9. An electronic skin structure, characterized in that, It includes multiple sensing units as described in any one of claims 1-8, the multiple sensing units are arranged in an array, the flexible substrates of adjacent sensing units are interconnected, each first grid wire is individually connected to a corresponding metal solder plate by a lead wire, and the multiple second grid wires are interconnected.

10. A method for manufacturing a sensing unit, used to manufacture the sensing unit as described in any one of claims 1-8, characterized in that, The manufacturing method includes the following steps: Prepare a silicon wafer, and after etching grooves with a depth of 100-200μm and a width of 500μm into the silicon wafer, form multiple deformation beams. Then fill the grooves with the first layer of PI adhesive and polish it to form a flat flexible substrate. A first dielectric layer, a temperature sensing layer, and a second dielectric layer are sequentially deposited on the deformable beam of the flexible substrate. Dry etching is used to preserve only the temperature-sensitive island located in the middle of the four pressure-sensitive layers, and then an insulating PI adhesive layer is applied for isolation. A pressure-sensing layer is deposited around the perimeter using a negative adhesive peeling process, covered with a second PI adhesive for encapsulation, and then a metal solder plate is made by separate wiring. After grinding the back side to the bottom of the groove, the entire device is peeled off in acetone solution to obtain an independent PI device. UV adhesive protrusions are formed by applying adhesive to the center of multiple deformable beams and curing at low temperature. Finally, the PI device is encapsulated in a silicone film in a sandwich manner to complete the flexible electronic skin sensor.

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