Transparent robot high-precision touch skin and preparation method thereof

Abstract

This invention discloses a transparent high-precision touch-sensitive skin for robots and its fabrication method, belonging to the field of robot perception and human-computer interaction technology. The skin is designed with two architectures: one is a single-functional layer structure integrating a transparent mesh touch layer to achieve high-precision touch positioning; the other is a dual-functional layer structure with a superimposed transparent pressure-sensing touch layer, simultaneously achieving touch positioning and precise pressure quantization. This invention uses a fine metal mesh with a line width of 2-20 μm and a spacing of 300-600 μm as the sensing unit, achieving a positioning accuracy of ≤0.1 mm while ensuring ≥84% light transmittance. Reliable interlayer bonding, pressure conduction, and electrical isolation are achieved through a transparent optical adhesive layer of a specific thickness. This skin combines high transparency, high sensing accuracy, excellent flexibility, and environmental adaptability, and can be widely used in service robots, medical robots, and industrial robots on complex curved surfaces requiring visual tactile interaction.

Description

Technical Field

[0001] This invention relates to the field of robot perception and human-computer interaction technology, and in particular to a transparent robot high-precision touch skin and its preparation method. Background Technology

[0002] As robotics technology advances towards human-robot coexistence and sophisticated collaboration, there is a growing demand for biomimetic features in the intelligence of robotic skin. An ideal robotic skin not only needs to mimic the tactile perception capabilities of human skin (such as precise positioning and force discrimination), but also often needs to maintain visual transparency to allow internal status indications, visual sensors to function, or to display mechanical structures, thereby enabling natural two-way interaction.

[0003] However, existing transparent touch solutions for robots suffer from the following interrelated fundamental technical bottlenecks: 1) Limited Functionality and Insufficient Sensing Dimensions: Current research largely focuses on achieving a single sensing modality. The most common approach is a transparent touch layer based on capacitive sensing, which can only detect the presence or absence of touch or perform rough two-dimensional localization, failing to continuously and accurately quantify the crucial physical quantity of contact pressure. This prevents robots from distinguishing between light touches and heavy pressure, severely limiting their application in scenarios requiring force feedback, such as precision assembly, safe interaction, and object recognition. Simply stacking touch and pressure sensing functions immediately leads to decreased transparency and signal crosstalk issues.

[0004] 2) The Inherent Contradiction Between Optical Transparency and Electrical / Sensing Performance: Achieving high-performance tactile sensing (high sensitivity, high resolution) typically relies on high-density, high-conductivity sensing units, which directly conflicts with the requirement for high transparency. Traditional indium tin oxide (ITO) thin films face problems of brittleness, high sheet resistance, and easy failure due to bending in large-area applications. While emerging metal mesh or nanowire solutions have advantages in flexibility, improper design can lead to wide lines or dense spacing that severely obstruct light, rendering the transparency meaningless. On the other hand, excessively pursuing extremely fine linewidths and sparse arrangements sacrifices signal strength, uniformity, and anti-interference capabilities, degrading the sensor's signal-to-noise ratio and compromising accuracy and reliability. This contradiction is the core obstacle restricting the development of high-performance transparent skin.

[0005] 3) The contradiction between structural rigidity and adaptability to complex curved surfaces: Many sensing solutions are based on rigid or semi-rigid substrates (such as glass, thick PET), which cannot conform to complex three-dimensional curved surfaces such as robot joints, fingers, and irregularly shaped shells. Although some flexible solutions are bendable, they lack the overall structural cutability and reliable interlayer encapsulation technology, and are prone to delamination, breakage, or performance drift under repeated deformation. In addition, how to maintain the stable relative position and signal isolation between functional layers under the premise of flexibility and deformability is also a major challenge.

[0006] Therefore, there is an urgent need in this field for an innovative integrated solution that can collaboratively innovate from multiple levels, such as material systems, micro-nano structure design, multi-layer architecture and packaging technology, to fundamentally break through the impossible triangle of function-transparency-flexibility and realize a truly usable, reliable and multifunctional transparent robotic tactile skin. Summary of the Invention

[0007] The present invention aims to provide a transparent robot high-precision touch skin and its preparation method, so as to solve the problem that transparency, touch function (especially pressure sensing), accuracy and surface adaptability are difficult to coordinate in the prior art.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides two types of transparent high-precision touch-sensitive skin for robots. One type has a single-functional layer structure, namely: A transparent robot high-precision touch skin is a flexible and cuttable stacked structure that contacts the layer to be applied, comprising a transparent mesh touch layer, a transparent OCA layer, and a transparent fur layer in sequence; The transparent mesh touch layer is composed of a transparent flexible substrate and a micro-metal mesh pattern. The linewidth of the micro-metal mesh pattern is 2-20 μm, and the spacing between adjacent lines (center-to-center spacing of conductors) is 300-600 μm. For example, a transparent flexible copper mesh fabricated on a PET transparent film substrate has a total thickness of 0.03 mm (copper layer 0.4-1.5 μm + PET substrate 30-100 μm), a mesh linewidth of 2-15 μm, and a channel width (line spacing) of 500 μm. The mesh transmittance is 85%-92% (400-760 nm visible light band; transmittance ≥90% at 2 μm linewidth, transmittance ≥85% at 15 μm linewidth, fluctuation ≤3%). Sheet resistance is 3.0-3.8 mΩ / □ (Calculation basis: Copper resistivity at room temperature ρ = 1.72 × 10⁻⁶) -8 Ω·m, copper layer thickness t=5±0.5μm, sheet resistance formula R □ =ρ / t, due to slight deviations in copper layer thickness caused by linewidth process fluctuations, sheet resistance fluctuates); Capacitance sensing range: reference capacitance 40-120pF (40-80pF when linewidth is 2μm, 60-120pF when linewidth is 15μm), capacitance change after touch ≥3pF; positioning accuracy ≤0.1mm; The transparent mesh touch layer (3) is a mesh structure with TX and RX layers respectively on both sides of the substrate. The substrate has an array of rhombic metal block units. The TX layer has several parallel X-direction sensing channels and the RX layer has several parallel Y-direction sensing channels, thus forming a metal mesh of orthogonal X-direction and Y-direction sensing channels on both sides of the substrate for detecting the coordinates of the touch plane. The sensing channels are electrically connected to the rhombic metal block units to form independent capacitive sensing units. For example, there are 32 sensing channels in the X direction, each channel is connected in series with 16 metal blocks, and there are 32 sensing channels in the Y direction, each channel is connected in series with 16 metal blocks, forming a 32×32 high-density sensing array. Each sensing channel is connected to the PIN end through a wire to connect to the flexible ribbon cable of the FPC. The wires of all sensing channels are all connected to the edge busbar area of ​​the touch layer. Among them, the X sensing channel wires are led out parallel to the left edge of the touch layer, and the Y sensing channel wires are led out parallel to the lower edge of the touch layer.

[0009] Preferably, the substrate layer is a transparent PC structural component for the robot, which is bonded to the transparent mesh touch layer with pressure-sensitive adhesive; the pressure-sensitive adhesive has a viscosity of ≥3N / cm, adapts to curved surfaces with an arc of ≤30°, and does not obstruct internal sensors; Preferably, the transparent OCA layer is an optically transparent film with a thickness of 0.05-0.1 mm, a light transmittance ≥95%, an adhesion strength ≥5 N / cm, and an insulation resistance ≥10 N / cm. 12 Ω; Preferably, the transparent fur layer material is transparent silicone, thermoplastic polyurethane, or acrylic, and is high-transparency silicone with a thickness of 0.1-0.3mm, a light transmittance of ≥92%, a Shore hardness of A50, and is flexible and wear-resistant.

[0010] Preferably, the total thickness of the transparent mesh touch layer is 0.02-0.06 mm, wherein the thickness of the metal layer is 3-8 μm; the transmittance of the metal mesh in the visible light band is ≥84%.

[0011] The transparent mesh touch layer adopts a bidirectional orthogonal routing design in both the X and Y directions, as detailed below: 1. Wiring layout: The X-direction wiring is perpendicular to the Y-direction wiring, forming a uniform rectangular sensing grid. The grid unit size is channel width × channel width, i.e., 0.5mm × 0.5mm. Each grid unit is an independent capacitive sensing unit. 2. Matching the grid width and channel width: Set the grid width (copper conductor width) to 2-15μm and the channel width (spacing between adjacent conductors) to 0.5mm. This ratio can maximize the light transmission area while ensuring signal strength and avoid conductors obstructing the internal view. 3. Relationship between channels and outgoing lines: There are 32 sensing channels in the X direction and 32 sensing channels in the Y direction. The outgoing lines of all channels converge to the edge bus area of ​​the touch layer. Among them, the X sensing channel outgoing lines are led out parallel to the left edge of the touch layer, and the Y sensing channel outgoing lines are led out parallel to the bottom edge of the touch layer. The outgoing line width is 0.1mm (wider than the grid width to reduce outgoing line resistance), and the spacing between adjacent outgoing lines is 0.15mm to avoid signal crosstalk between outgoing lines. 4. Signal output method: The output end is connected to the flexible ribbon cable of FPC (flexible printed circuit board) through transparent conductive adhesive. The FPC ribbon cable extends from the bus area to the main control chip inside the robot to realize the transmission of sensing signals.

[0012] Another type is a dual-functional layer structure, namely: a transparent robot high-precision touch skin, which is a flexible and cuttable stacked structure that contacts the layer being applied, and includes, in sequence, a transparent mesh touch layer, a transparent OCA layer II, a transparent pressure-sensitive touch layer, a transparent OCA layer I, and a transparent fur layer; The transparent pressure-sensitive touch layer can detect vertical pressure, with a pressure detection range of 0.05-30N and a detection accuracy of ≤0.05N.

[0013] This invention also proposes a method for preparing the aforementioned two types of transparent robotic high-precision touch-sensitive skin, comprising the following steps: S1: A metal mesh is fabricated on a transparent flexible substrate using a patterning process, and signal extraction electrodes are made to obtain a transparent mesh touch layer; S2: Bond the layers together; S3: Perform vacuum pressing treatment under the following conditions: pressure 0.5-1.5MPa, temperature 50-80℃, time 5-15 minutes, to obtain a transparent robot high-precision touch skin; S4: Select an appropriate position on the robot body as the substrate layer, and cut and attach the transparent robot high-precision touch skin to the surface of the substrate layer according to its curved shape.

[0014] Preferably, the patterning process in S20 employs a layered sputtering process, referring to the patent publication CN120600377A entitled "Conductive Film, Metal Mesh Touch Screen Sensor, Touch Module and its Preparation Method": S1. Substrate pretreatment: Ultrasonic cleaning removes surface oil, plasma treatment or chemical etching improves surface activity; the substrate is placed on a carrier in a vacuum chamber to ensure uniform deposition; S2. Vacuum environment setup: Evacuate to 10°C. -3 ~10 -6 Pa removes oxygen and moisture, preventing copper from oxidizing; S3. Copper target excitation: Inert gas - argon gas is introduced, and a high-voltage electric field is applied to make argon ions bombard the copper target, sputtering out copper atoms. The copper atoms are deposited on the substrate surface under the guidance of the electric field or magnetic field. S4. Coating Deposition Control: The copper layer thickness is controlled by adjusting parameters such as sputtering power, gas pressure, and deposition time. Layered sputtering during copper plating can release the stress on the copper, thereby improving its bending resistance.

[0015] It can be a photolithography-etching process, a nanoimprint process, or a laser direct writing process.

[0016] Preferably, S2 is divided into two cases: When the transparent robot's high-precision touch skin is a single-functional layer structure (i.e., excluding the transparent pressure-sensitive touch layer), the transparent mesh touch layer, the transparent OCA layer, and the transparent fur layer are aligned and stacked in sequence; When the transparent robot's high-precision touch skin has a dual-functional layer structure (i.e., including a transparent pressure-sensitive touch layer), the transparent pressure-sensitive touch layer is first stacked with the transparent fur layer through the transparent OCA layer I; then the transparent mesh touch layer is stacked on the transparent pressure-sensitive touch layer through the transparent OCA layer II.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention provides a scalable modular stacked architecture. The single-function layer structure achieves high-precision touch positioning of ≤0.1mm through a transparent mesh touch layer, meeting basic interaction requirements. The dual-function layer structure, building upon this, innovatively introduces a transparent pressure-sensitive touch layer, mechanically coupled through a low-modulus transparent OCA layer I and electrically isolated through a highly insulating transparent OCA layer II. This design allows touch positioning (XY coordinates) and pressure quantization (Z-axis force value) signals to be acquired independently, synchronously, and with high precision. The mechanism lies in the fact that the pressure layer, based on piezoresistive or piezocapacitive principles, only responds to stress perpendicular to the layer, physically orthogonal to the capacitive sensing principle of the mesh layer used for planar positioning. Combined with the intermediate insulating layer, signal crosstalk is fundamentally avoided. This enables the robot to obtain complete tactile information about where it is contacting and how much force is applied, making precision operations possible.

[0018] 2. This invention achieves an optimal balance between optical and electrical performance through precise parametric design of a micro-metal mesh. The metal mesh linewidth is limited to 2-20 μm, and the spacing between adjacent lines is 300-600 μm. The mechanism is that the extremely fine linewidth (e.g., 2-5 μm) is close to the lower limit of visible light wavelength, resulting in extremely weak diffraction and blocking effects. This is the physical basis for achieving an overall transmittance of ≥84% (locally up to 92%). Simultaneously, the metal wires within this size range possess sufficiently low sheet resistance (3.0-3.8 mΩ / □), ensuring low-loss transmission and strong noise immunity of the capacitive sensing signal. The mesh spacing (channel width) determines the sensing unit density; the 300-600 μm spacing, while forming a uniform electric field, ensures a theoretical resolution for touch positioning higher than 0.1 mm. This fine-line, moderately spaced pattern, like an extremely fine invisible grid, is almost invisible to the eye, but electrically constitutes a high-performance distributed sensing array, thus solving the problem of the mutual exclusion of transparency and performance.

[0019] 3. This invention utilizes fully flexible materials, with a total thickness controllable to the sub-millimeter level (0.2-0.8mm), giving it excellent bendability. The ability to freely cut each layer allows for perfect fit to complex curved surfaces of robots with an angle of ≤30°. The underlying mechanism is that the transparent OCA layer not only provides adhesive strength (≥5N / cm), but its inherent elastic modulus absorbs and disperses internal shear stress generated by the fit to the curved surface, preventing warping or delamination caused by rigid connections. The transparent skin layer (silicone, TPU, or acrylic) provides wear-resistant and scratch-resistant protection, with a friction life of ≥30,000 cycles, ensuring long-term reliability. The vacuum pressing process completely eliminates interlayer air bubbles, ensuring that the interfaces do not separate due to air expansion during bending, making the entire skin module a unified whole with uniform mechanical properties and long-life bending fatigue resistance.

[0020] 4. The preparation method proposed in this invention, especially the combination of solid OCA film and vacuum lamination process, is key to ensuring product consistency and high yield. Compared to liquid optical adhesives, solid OCA film has uniform and controllable thickness, no flowability or curing shrinkage issues, thus avoiding optical distortion (Newton's rings) and internal stress. Vacuum lamination is carried out under pressure of 0.5-1.5MPa and temperature of 50-80℃. Its mechanism is that, under the premise of removing air, appropriate heat and force induce plastic flow of OCA, forming a molecular-level close contact with the upper and lower layer surfaces, achieving a defect-free and strong optical and mechanical bond. This process is stable, highly repeatable, and suitable for mass production. At the same time, FPC achieves high-density, high-reliability flexible electrical connection between the sensor array and the signal processor through ACF hot-press bonding, completing a complete and stable link from sensing to signal output.

[0021] 5. In summary, this invention, through the three-in-one technological innovation of micro-grid sensing units, modular functional layer architecture, and solid adhesive vacuum pressing integration process, systematically produces a high-performance, stable, and reliable transparent robot touch feedback skin, which strongly promotes the practical application of high-performance bionic skin in next-generation robots. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the layer structure of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the mesh and overall wire layout of the transparent mesh touch layer in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the transparent mesh touch layer FU layer (top surface wiring) in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the transparent mesh touch layer FD layer (lower surface wiring) in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the layer structure of Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of the dual-touch layer mesh and overall cable routing layout in Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the FD layer (the lower mesh touch layer) in Embodiment 2 of the present invention; Figure 8 This is a schematic diagram of the FU layer (the upper pressure-sensitive touch layer) in Embodiment 2 of the present invention.

[0023] In the diagram: 1: Transparent fur layer; 2: Transparent OCA layer; 201: Transparent OCA layer I; 202: Transparent OCA layer II; 3: Transparent Mesh touch layer; 4: Object layer; 5: Transparent pressure-sensitive touch layer. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with existing known technologies. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] Example 1. Transparent touch skin with a single functional layer structure: This embodiment provides a transparent touch-sensitive skin for use in a robot's facial interaction panel, the structure of which is as follows: Figure 1-4 As shown, this is a single-function layer structure.

[0026] 1. Structure and Materials: A transparent high-precision touch-sensitive skin for robots, which is a flexible, cuttable, and stacked structure in contact with the substrate layer 4, comprising, from top to bottom: Transparent fur layer 1: Made of transparent wear-resistant silicone sheet with a thickness of 0.2mm, light transmittance of 92%, and Shore hardness of A50.

[0027] Transparent OCA layer 2: 0.08mm thick, 95.5% light transmittance, 5.2N / cm adhesion, and ≥10Ω insulation resistance. 12 Ω solid optically transparent film.

[0028] Transparent Mesh Touch Layer 3: A copper mesh pattern is formed on a 0.025mm thick PET transparent film substrate using photolithography. The mesh line width is 5μm, the channel width (line spacing) is 0.5mm, the copper layer thickness is 5±0.5μm, and the total thickness of this layer is 0.03mm. The mesh has a transmittance of 89% in the visible light band (550nm) and a sheet resistance of 3.5mΩ / □. 32 sensing channels are set in both the X and Y directions. The channel leads converge at a busbar at the layer edge and are connected to a 0.3mm conductor-spacing FPC flexible cable via anisotropic conductive film (ACF) thermo-bonding.

[0029] Layer 4: This is a curved transparent PC (polycarbonate) panel for the robot's face, with an arc of approximately 20°. The skin is bonded to this panel using a layer of transparent pressure-sensitive adhesive with a strength of 3.5 N / cm.

[0030] The core of this embodiment is the precise routing design of the transparent mesh touch layer. By optimizing the mesh width, channel width, and wire layout, high-precision touch positioning is achieved while ensuring high transparency. Specific details are as follows: Table 1. Single-functional layer structure and core parameters

[0031] The mesh routing and outgoing cable design in this embodiment: The transparent mesh touch layer adopts an orthogonal routing design in both the X and Y directions, as follows: 1) Routing layout: The X-direction routing is perpendicular to the Y-direction routing, forming a uniform rectangular sensing mesh. The mesh unit size is channel width × channel width, i.e., 0.5mm × 0.5mm. Each mesh unit is an independent capacitive sensing unit; 2) Matching mesh width and channel width: The mesh width (copper conductor width) is set to 2-15μm, and the channel width (spacing between adjacent conductors) is set to 0.5mm. This ratio maximizes the light-transmitting area while ensuring signal strength and avoiding conductors obstructing the internal view; 3) Relationship between channels and outgoing lines. : A total of 32 sensing channels are set in the X direction and 32 sensing channels are set in the Y direction. The outgoing ends of all channels are converged to the edge bus area of ​​the touch layer. Among them, the X sensing channel outgoing line is led out parallel to the left edge of the touch layer, and the Y sensing channel outgoing line is led out parallel to the lower edge of the touch layer. The outgoing line width is 0.1mm (wider than the grid width to reduce outgoing line resistance), and the spacing between adjacent outgoing lines is 0.15mm to avoid signal crosstalk between outgoing lines; 4) Signal outgoing method: The outgoing line is connected to the FPC flexible cable through transparent conductive adhesive. The FPC cable extends from the bus area to the main control chip inside the robot to realize the transmission of sensing signals.

[0032] The functional implementation process of this embodiment: When an external object touches the transparent skin layer, the pressure is transmitted through the transparent OCA layer to the transparent mesh touch layer. The capacitance value of the capacitance sensing unit formed by the X / Y sensing channel corresponding to the touch position changes. The main control chip scans the 32 channels in the X / Y direction, identifies the channel number corresponding to the capacitance change, and calculates the precise touch coordinates (positioning accuracy ≤0.1mm) by combining the mesh unit size (0.5mm×0.5mm). At the same time, the fully transparent layer structure ensures that the indicator lights, cameras and other components under the skin can work normally, realizing the synergistic effect of touch interaction and visual feedback. It is suitable for scenarios such as transparent touch windows for robots and facial interaction panels.

[0033] 2. Preparation method: S1: On a PET transparent film substrate, a copper mesh pattern with the above parameters is prepared by photolithography-etching process, and bus electrodes are made at the edges to obtain a transparent Mesh touch layer 3.

[0034] S2: Accurately align and stack the transparent fur layer 1, transparent OCA layer 2, and transparent Mesh touch layer 3 in sequence.

[0035] S3: Place the stacked structure in a vacuum press and press it for 10 minutes at a pressure of 0.8MPa and a temperature of 65℃ to completely remove interlayer air bubbles and obtain a complete transparent touch skin.

[0036] S4: Based on the CAD 3D contour data of the robot's facial panel, the skin is precisely cut using laser. Then, the skin is smoothly adhered to the surface of the substrate layer 4 through the pressure-sensitive adhesive layer on the back.

[0037] 3. Performance Testing and Results The skin prepared in this embodiment has been tested and found to have the following effects: Visual performance: The overall light transmittance is high, and the LED indicator patterns in the panel under the skin are clearly visible, realizing the visualization of the interactive interface.

[0038] Touch performance: Touch positioning accuracy reaches 0.08mm, the reference capacitance is about 60pF, the capacitance change caused by finger touch is ≥5pF, and the response is sensitive.

[0039] Mechanical properties: The skin is soft and fits perfectly to a 20° curved surface. After 10,000 bending fatigue tests, the touch function has not diminished and the surface shows no obvious wear.

[0040] Example 2. Transparent touch skin with dual-functional layer structure: This embodiment provides a tactile skin for use in the end effector of a robot's dexterous hand, the structure of which is as follows: Figure 5-8 As shown, this is a dual-functional layer structure.

[0041] 1. Structure and Materials: A transparent, high-precision touch-sensitive skin for robots, comprising a flexible, cuttable, stacked structure that contacts the substrate layer 4, and from top to bottom: Transparent fur layer 1: Made of transparent acrylic film with a thickness of 0.15mm, light transmittance of 93%, and abrasion resistance of ≥40,000 times.

[0042] Transparent OCA layer I201: A low-modulus optically transparent film with a thickness of 0.06 mm and a modulus of 0.4 MPa is used to optimize the transmission of minute pressures.

[0043] Transparent pressure-sensitive touch layer 5: This layer is a composite layer with transparent pressure-sensitive polyimide (PI) as the functional film. A copper mesh electrode with a linewidth of 8μm and a channel width of 0.4mm is formed on its surface using a laser direct-writing process. The pressure detection range of this layer is 0.1-20N.

[0044] Transparent OCA layer II 202: 0.08mm thick, with an insulation resistance ≥10 Ω·cm. 12 Ω-sized optically transparent film for electrical isolation.

[0045] Transparent Mesh Touch Layer 3: Its material and mesh parameters are the same as in Example 1, and it is used for touch positioning.

[0046] Layer 4: This is a transparent resin structure for the robot's fingertips. The skin is attached to it through a 0.3mm thick layer of transparent silicone cushioning adhesive.

[0047] This embodiment adds a transparent pressure-sensitive touch layer based on embodiment 1. Through the collaborative design of the dual touch layers, it achieves touch positioning and precise pressure quantification while retaining the transparency characteristic. The core technical details are as follows: Table 2. Dual-functional-layer structure and core parameters

[0048] The dual-touch layer routing and outgoing cable coordination design in this embodiment: 1) Pressure-sensing touch layer routing: A planar mesh + partitioned channel design is adopted, with a mesh width of 2-15μm and a channel width of 0.4mm, forming a finer sensing mesh (unit size 0.4mm×0.4mm) than the Mesh layer, ensuring uniform pressure detection. A total of 16 pressure-sensing channels are set, running parallel to the right edge of the touch layer, with a line width of 0.1mm and a spacing of 0.15mm, separated from the Mesh layer routing area (left and bottom sides) to avoid signal interference. 2) Mesh touch layer routing: Completely consistent with scheme 1, with 32 channels in each of the X and Y directions, and lines running from the left and bottom edges to ensure touch positioning accuracy. 3) Channel and line coordination: The pressure layer lines and Mesh layer lines are both converged to the same edge bus, but separated by an insulating strip, and connected to different signal interfaces of the FPC cable, achieving independent transmission of pressure and position signals. The main control chip ultimately performs signal fusion.

[0049] The functional implementation process of this embodiment: When an external force touches the fur layer, the pressure is transmitted sequentially through OCA layer 1 to the transparent pressure-sensitive touch layer. The resistance of the pressure-sensitive conductive film decreases linearly with increasing pressure (10MΩ at 0.1N, 100Ω at 20N). The pressure sensing channel converts the resistance change into an electrical signal and transmits it to the main control chip. At the same time, the Mesh touch layer identifies the X / Y coordinates of the touch point. The main control chip fuses the two sets of signals through an algorithm and outputs composite data of touch position + pressure value (e.g., (X: 20.3mm, Y: 35.6mm) + pressure: 3.2N). The transparent layer structure ensures that the internal vision sensor can acquire images of the contact area in real time, making it suitable for precision operation scenarios such as the contact end of medical robots and end effectors with vision detection.

[0050] 2. Preparation method: S1: Prepare transparent pressure-sensitive touch layer 5 and transparent mesh touch layer 3 respectively. The mesh of the pressure-sensitive layer is prepared using a laser direct writing process.

[0051] S2: First, align and stack the transparent fur layer 1, transparent OCA layer I 201, and transparent pressure-sensitive touch layer 5, and pre-press them together. Then, align and stack this composite layer with the transparent OCA layer II 202 and the transparent Mesh touch layer 3.

[0052] S3: Vacuum press the entire structure under the following conditions: pressure 1.0MPa, temperature 70℃, time 12 minutes.

[0053] S4: Cut and fit to the curved surface of the robot's fingertip.

[0054] 3. Performance Testing and Results: The skin prepared in this embodiment has been tested and found to have the following effects: Multifunctional sensing: It can simultaneously output the two-dimensional coordinates X, Y of the touch point and the vertical pressure value F. For example, when pinching a grape, it can provide real-time feedback on the contact position and the gripping force of approximately 0.8N.

[0055] High-precision force sensing: The pressure detection accuracy reaches 0.03N, and the linearity is good within the light force operation range of 0-5N.

[0056] Signal independence: Thanks to the high insulation of the transparent OCA layer II202, there is no crosstalk between the pressure signal and the touch positioning signal.

[0057] Scene compatibility: High transparency ensures an unobstructed field of view for the miniature camera integrated inside the fingertip, enabling visual-tactile fusion perception.

[0058] Example 3. Variant of the single-functional-layer structure: This embodiment provides another single-function layer structure, mainly demonstrating variations in materials and processes.

[0059] 1. Key points of structure and preparation: Transparent Mesh Touch Layer 3: A silver nanowire mesh with a linewidth of 2 μm and a channel width of 0.6 mm is prepared using a 0.02 mm thick transparent polyimide (PI) film as a substrate through nanoimprint lithography. This layer has a light transmittance of 92%.

[0060] Transparent fur layer 1: Made of thermoplastic polyurethane (TPU) film with a thickness of 0.1 mm.

[0061] Patterning process: A nanoimprinting process is used. First, grid grooves are imprinted on the PI substrate, then silver nanowire conductive paste is filled in, and after curing, polishing is performed to remove excess material. The remaining processes or materials are the same as in Example 1.

[0062] 2. Results: This variant achieves higher transparency (92%) and better flexibility, with a minimum bending radius of 1mm, making it suitable for interactive joint surfaces that require extreme bending, while maintaining a positioning accuracy of ≤0.1mm.

[0063] Example 4. Variant of the dual-functional layer structure: This embodiment provides another dual-functional layer structure, mainly demonstrating a variant of the pressure-sensing layer.

[0064] 1. Key points of structure and preparation: Transparent pressure-sensitive touch layer 5: Composed of transparent conductive fabric and quantum tunnel composite material. Its pressure sensing is based on the piezoresistive principle, and the detection range is widened to 0.05-30N.

[0065] Preparation method: After the pressure sensing layer 5 and the mesh layer 3 are prepared separately, they are aligned and pressed together in a vacuum environment using a transparent OCA layer II 202 to ensure complete signal isolation between the two layers. The remaining processes or materials are the same as in Example 2.

[0066] 2. Results: This variant demonstrates the replaceability of pressure-sensing materials, increases the pressure detection limit to 30N, and is suitable for industrial gripping scenarios that require sensing greater grip strength, while maintaining transparency.

[0067] Comparative Example 1. Touch layer with out-of-range mesh parameters: This comparative example aims to illustrate that when the key parameters of the transparent Mesh touch layer 3 deviate from the scope defined in this invention, the performance will significantly decrease.

[0068] 1. Structure and Comparison: Except for the parameters of the transparent Mesh touch layer 3, the structure of the other layers is the same as in Example 1. In this comparative example, the mesh is made using conventional screen printing technology, with a line width of 50μm and a channel width of 2mm.

[0069] 2. Performance Testing and Comparison: Transparency: Due to the excessive width of the metal wires, severe obstruction occurs, and the overall light transmittance drops to approximately 70%, severely impairing the clarity of visual elements beneath the skin.

[0070] Touch accuracy: The sensor grid unit size is too large (2mm×2mm), the theoretical positioning accuracy is only about 1mm, and the actual measured accuracy is ≥1.5mm, which makes it impossible to achieve fine interaction.

[0071] Signal strength: Although the increased line width increases the capacitance reference value, the severe capacitive coupling between adjacent channels can easily lead to false triggering and coordinate jumps.

[0072] Comparison of Comparative Example 1 and Example 1: When the grid line width is >20μm and the channel width is >0.6mm, the core requirements of high transparency and high precision cannot be met at the same time, which proves the necessity of the parameter range of the present invention.

[0073] Comparative Example 2. Structure lacking a transparent OCA layer: This comparative example aims to illustrate the key role of the transparent OCA layer in the structure of this invention.

[0074] 1. Structure and Comparison: Refer to the structure of Example 1, but omit the transparent OCA layer 2, and try to directly bond the transparent fur layer 1 and the transparent Mesh touch layer 3 with ordinary liquid transparent adhesive (LOCA).

[0075] 2. Performance Testing and Issues: Optical defects: Air bubbles are generated during the application of liquid adhesive and are difficult to remove completely, forming fixed optical distortion points after curing. Uneven adhesive layer thickness leads to Newton's rings, severely damaging the visual effect.

[0076] Mechanical reliability: The internal stress generated by curing shrinkage causes localized micro-wrinkles in the flexible copper mesh, leading to abnormally increased resistance in some channels and even breakage. During curved surface bonding and bending operations, interlayer delamination is prone to occur.

[0077] Electrical performance: Ordinary liquid adhesive has unstable insulation performance. In high humidity environments, the insulation resistance decreases, causing the touch signal baseline to drift.

[0078] Comparison of Example 2 and Example 1: Without a solid optically transparent film (OCA) and the corresponding vacuum bonding process, it is impossible to achieve stable and reliable optical, mechanical and electrical properties, proving that the specific OCA layer and process of the present invention are indispensable.

[0079] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A transparent robotic high-precision touch skin, comprising a flexible, cuttable, stacked structure in contact with the substrate layer (4), characterized in that, It consists of a transparent Mesh touch layer (3), a transparent OCA layer (2), and a transparent fur layer (1) in sequence. The transparent mesh touch layer (3) is composed of a transparent flexible substrate and a fine metal mesh pattern; the line width of the fine metal mesh pattern is 1-10μm, and the spacing between adjacent lines is 300-600μm; The transparent mesh touch layer (3) is a mesh structure with TX and RX layers respectively on both sides of the substrate. The substrate has an array of rhombic metal block units. The TX layer has several parallel X-direction sensing channels and the RX layer has several parallel Y-direction sensing channels, thus forming a metal mesh of orthogonal X-direction and Y-direction sensing channels on both sides of the substrate for detecting the coordinates of the touch plane. The sensing channels are electrically connected to the rhombic metal block units to form independent capacitive sensing units. Each sensing channel is connected to the PIN end through a wire for connecting the flexible ribbon cable of the FPC. The wires of all sensing channels are converged to the edge busbar area of ​​the touch layer. Among them, the X sensing channel wires are led out parallel to the left edge of the touch layer and the Y sensing channel wires are led out parallel to the lower edge of the touch layer.

2. The transparent robot high-precision touch skin according to claim 1, characterized in that, The attached layer (4) is a transparent PC structural component for robots, which is bonded to the transparent Mesh touch layer (3) by pressure-sensitive adhesive; the pressure-sensitive adhesive has a viscosity of ≥3N / cm and can adapt to curved surfaces with an arc of ≤30°.

3. The transparent robot high-precision touch skin according to claim 1, characterized in that, The transparent OCA layer (2) is an optically transparent adhesive film with a thickness of 0.05-0.1 mm, a light transmittance ≥95%, an adhesion strength ≥5 N / cm, and an insulation resistance ≥10 N / cm. 12 Ω.

4. The transparent robot high-precision touch skin according to claim 1, characterized in that, The transparent fur layer (1) is made of transparent silicone, thermoplastic polyurethane or acrylic, with a thickness of 0.1-0.3 mm, a light transmittance of ≥92%, and a Shore hardness of A50.

5. The transparent robot high-precision touch skin according to claim 1, characterized in that, The total thickness of the transparent mesh touch layer (3) is 0.02-0.06 mm, of which the thickness of the metal layer is 3-8 μm; the transmittance of the metal mesh in the visible light band is ≥84%.

6. The transparent robot high-precision touch skin according to claim 1, characterized in that, The output terminal is connected to the flexible ribbon cable of the FPC via transparent conductive adhesive, and the FPC ribbon cable extends from the busbar area to the main control chip inside the robot.

7. A transparent robot high-precision touch skin, which is a flexible and cuttable layered structure in contact with the substrate layer (4), characterized in that, It consists of a transparent mesh touch layer (3), a transparent OCA layer II (202), a transparent pressure-sensitive touch layer (5), a transparent OCA layer I (201), and a transparent fur layer (1). The transparent pressure-sensitive touch layer (5) can detect vertical pressure, with a pressure detection range of 0.05-30N and a detection accuracy of ≤0.05N.

8. A method for preparing a transparent robotic high-precision touch-sensitive skin according to any one of claims 1 or 7, characterized in that, Includes the following steps: S1: A metal mesh is prepared on a transparent flexible substrate by a patterning process, and leads and pins are made to obtain a transparent mesh touch layer (3). S2: Bond the layers together; S3: Perform vacuum pressing treatment under the following conditions: pressure 0.5-1.5MPa, temperature 50-80℃, time 5-15 minutes, to obtain a transparent robot high-precision touch skin; S4: Select an appropriate position of the robot body as the substrate (4), and cut and attach the transparent robot high-precision touch skin to the surface of the substrate (4) according to its curved shape.

9. The method for preparing a transparent robotic high-precision touch-sensitive skin according to claim 8, characterized in that, The patterning process employs a layered sputtering process: S1. Substrate pretreatment: Ultrasonic cleaning removes surface oil, plasma treatment or chemical etching improves surface activity; the substrate is placed on a carrier in a vacuum chamber to ensure uniform deposition; S2. Vacuum environment setup: Evacuate to 10°C. -3 ~10 -6 Pa removes oxygen and moisture, preventing copper from oxidizing; S3. Copper target excitation: Inert gas - argon gas is introduced, and a high-voltage electric field is applied to make argon ions bombard the copper target, sputtering out copper atoms. The copper atoms are deposited on the substrate surface under the guidance of the electric field or magnetic field. S4. Coating deposition control: The copper layer thickness is controlled by adjusting parameters such as sputtering power, gas pressure, and deposition time.

10. For sputtering-etching process, nanoimprinting process or laser direct writing process.

11. The method for preparing a transparent robot high-precision touch-sensitive skin according to claim 8, characterized in that, S2 can be divided into two cases: When the transparent robot's high-precision touch skin is a single-function layer structure, the transparent Mesh touch layer (3), the transparent OCA layer (2), and the transparent fur layer (1) are aligned and stacked in sequence; When the transparent robot high-precision touch skin has a dual-functional layer structure, the transparent pressure-sensitive touch layer (5) is first stacked with the transparent fur layer (1) through the transparent OCA layer I (201); then the transparent Mesh touch layer (3) is stacked on the transparent pressure-sensitive touch layer (5) through the transparent OCA layer II (202).

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