Fabric circuit, method of making the same and electronic system

Abstract

The application belongs to the field of intelligent textile technology and flexible electronics, and discloses a fabric circuit, a preparation method thereof and an electronic system. The fabric circuit comprises a substrate and a conductive path. The substrate is an integrally-formed insulating weft-knitted spacer fabric, which comprises a first surface layer, a second surface layer and a spacer layer. One or more conductive paths integrally form at least three interconnection structures in the three-dimensional space of the substrate through a digital knitting program, the interconnection structures being a projected staggered insulating structure, an interlayer transfer structure, a three-dimensional packaging structure and an electrode connection structure. The preparation method comprises the following steps: firstly, designing the structure of the fabric circuit; secondly, generating a program; and thirdly, executing the digital knitting program to obtain the fabric circuit. The electronic system comprises an external device and the fabric circuit. The external device is electrically connected with the electrode connection structure of the fabric circuit. The application can realize full-function three-dimensional circuit integration with high density, high complexity, high reliability and high design freedom on the premise of maintaining the inherent advantages of the fabric.

Description

Technical Field

[0001] This invention belongs to the field of intelligent textile technology and flexible electronics, and relates to a fabric circuit, its preparation method and electronic system. Background Technology

[0002] With the rapid development of flexible electronics and wearable devices, there are increasing demands on the flexibility, stretchability, and breathability of circuits, making traditional rigid printed circuit boards (PCBs) unsuitable. Flexible circuits based on fabrics, due to their excellent flexibility, breathability, and wearing comfort, have become a key technology for realizing the next generation of human-computer interaction and have received widespread attention in fields such as health monitoring and motion recognition.

[0003] Constructing conductive paths within fabrics currently relies primarily on printing technologies (such as screen printing and inkjet printing) and textile technologies (such as introducing conductive yarns). Among these, the method of introducing conductive yarns into fabrics to construct circuits is considered a more promising approach as it better preserves the fabric's inherent softness, breathability, and stretchability. Based on their structural characteristics and the evolution of manufacturing processes, existing fabric circuit technologies can be broadly categorized into the following four types:

[0004] 1) Planar or Single-Layer Fabric Circuit Technology: This technology is the basic form of fabric circuits, forming circuits by introducing conductive yarns onto the surface or inside a single-layer fabric substrate. For example, patent application CN119967705A discloses a one-piece molded multilayer flexible fabric circuit, which achieves one-piece molding by embedding multiple conductive yarns inside a single-layer warp-knitted fabric and designing the connection relationship. Reference 1 (Washability of E-Textiles: Washing Behavior of TextileIntegrated Circuits Depending on Textile Substrate, Circuit Material and Integration Method. Adv. Funct. Mater., vol. 35, art. no. 2417344, 2025.) and patent application CN112438868A both involve laying wires on a single layer of fabric, lacking vertical interconnection capabilities. However, its structure is essentially wiring in a two-dimensional plane, fundamentally limited by its inability to solve the problem of intersections of conductive paths in planar projection. When circuit designs require crossovers, external jumpers, bridging, or additional insulation layers are usually necessary, which severely limits the complexity, wiring density, and functional integration potential of the circuit design.

[0005] 2) Multilayer Adhesive / Laminated 3D Circuits: To overcome the limitations of single-layer wiring and obtain more wiring space, researchers have developed techniques for stacking and compositing multiple pre-prepared single-layer fabric circuits through methods such as hot pressing, adhesive bonding, or sewing. For example, in Reference 2 (3DKnITS: Three-dimensional Digital Knitting of Intelligent Textile Sensor for Activity Recognition and Biomechanical Monitoring. In 202244th Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), Glasgow, UK, 2022, pp. 2403-2409.), three layers of fabric are hot-pressed using TPU film; patent CN113358249B uses cross-stacked double-layer fabric; and patent CN112525392B uses adhesive bonding and sewing processes, all of which have achieved multilayer sensing structures. However, these methods generally introduce external adhesive layers, films, or mechanical connections that are not formed through weaving processes (weaving or knitting). This not only results in fabrics that are stiff, heavy, and non-breathable, compromising their inherent softness and comfort, but also makes the interlayer interfaces highly susceptible to fatigue failure, poor contact, or delamination under dynamic mechanical stress (such as repeated bending, stretching, and washing), leading to poor long-term reliability. More importantly, their "interlayer interconnection" relies on subsequent bonding and perforation processes, rather than a controllable conductive path transfer formed integrally during the weaving process.

[0006] 3) Multilayer Woven Fabric Circuits: Woven weaving naturally supports the creation of multilayer structures, making it possible to integrate three-dimensional circuits during the weaving process. For example, reference 3 (Opportunities with Multi-Layer Weave Structures in Woven E-Textile Design. ACM Trans. Comput.-Hum. Interact., vol.31, no. 5, art. no. 62, pp. 1-38, Oct. 2024.) systematically explores the opportunities to enrich the capabilities of electronic textiles using multilayer woven structures. This type of technology can produce structurally stable fabrics containing complex configurations of conductive yarns. However, the inherent characteristics of woven fabrics also present limitations: their structure is generally denser, and their flexibility and elasticity (especially biaxial stretchability) are generally lower than those of knitted fabrics, which may affect wearing comfort. More importantly, achieving flexible, precise, and reliable vertical transfer and interconnection of conductive paths in woven architectures (similar to "through holes" in PCBs) is extremely challenging in terms of manufacturing processes, which limits its ease of constructing complex, reconfigurable three-dimensional circuit topologies and design freedom.

[0007] 4) Knitted Spacer Fabric Circuits: Weft-knitted or warp-knitted spacer fabrics possess an integrally formed double-layer (surface layer) structure and an intermediate connecting layer (spacer layer), providing a natural three-dimensional space for circuits. Existing technologies have utilized this characteristic to develop functional fabrics such as electrothermal and piezoresistive sensing. For example, patent CN120649222B discloses a flexible electrothermal weft-knitted spacer fabric and its preparation method; patent CN120702636B discloses a flexible piezoresistive sensing array based on a triangular truss mesh structure weft-knitted spacer fabric, where the upper and lower conductive yarns are used to form sensing units, and the layout of the conductive path is determined by the sensing function and is static and fixed. These works demonstrate the feasibility of integrating specific electronic functions in a three-dimensional fabric space. However, existing solutions share common drawbacks: their circuit patterns and interconnections are determined by a pre-defined single function (such as heating or sensing), and cannot be changed as needed; they lack programmability to dynamically merge / separate conductive paths during the weaving process to reconstruct the circuit topology; they fail to systematically treat the upper and lower layers as independent wiring layers to achieve conflict-free cross-wiring, nor do they enable inter-layer transfer of conductive paths at arbitrary locations. Therefore, existing technologies are essentially still "electronic components with fixed functions," rather than "general-purpose circuit platforms" capable of flexibly integrating diverse electronic functional modules (such as power supplies, processors, sensors, communication modules, etc.).

[0008] In summary, existing fabric circuit technologies all suffer from significant compromises or fundamental limitations in their evolution towards three-dimensional integration and high-density interconnection: planar single-layer technology cannot solve the wiring crossover problem; bonding / lamination methods sacrifice the flexibility, breathability, and long-term reliability of fabrics; multi-layer woven technology faces challenges in terms of flexibility and flexible three-dimensional interconnection; and existing knitted spacer fabric circuits are functionally limited and lack versatility and programmable interconnection capabilities.

[0009] Therefore, there is still a lack in the field of fabric circuit technology that can simultaneously meet all of the following requirements: (1) maintaining the inherent flexibility, stretchability, and breathability of the fabric; (2) achieving high-density, conflict-free cross-wiring within a single piece of fabric through an integrated weaving process; (3) providing controllable and reliable interlayer transfer capability of conductive paths; (4) possessing reconfigurability and programmability of circuit topology; and (5) being able to integrate complex electronic systems as a general-purpose platform. This general-purpose, highly reliable three-dimensional interconnected fabric circuit platform is a key foundation for constructing complex, fully flexible electronic systems and is also a technological bottleneck that urgently needs to be overcome in the current field of smart textiles.

[0010] Therefore, there is an urgent need in this field for an innovative and universal technical solution that can overcome the functional limitations of existing technologies while maintaining the inherent advantages of fabrics, and achieve a full-function three-dimensional circuit integration and systematization solution with high density, high complexity, high reliability, and high design freedom. Summary of the Invention

[0011] The purpose of this invention is to solve the problems existing in the prior art and provide a fabric circuit, its preparation method and electronic system. It aims to provide a fully integrated platform that combines the inherent flexibility of fabric, high-density three-dimensional wiring capability, topology programmability and system-level encapsulation protection. Its core technical path is to deeply integrate digital programming control with weft knitting process, and to build a fabric circuit with projection interlaced insulation structure, interlayer transfer structure, three-dimensional encapsulation structure, electrode connection structure and topology programmability in a single weaving process, so as to realize the leap from "functional fabric" to "programmable three-dimensional circuit platform".

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] A fabric circuit includes a substrate and one or more conductive paths;

[0014] The base is an integrally formed insulating weft-knitted spacer fabric, including a first surface layer, a second surface layer, and a spacer layer connected between the first surface layer and the second surface layer.

[0015] Each conductive path is formed by one or more conductive yarns embedded in the substrate through a knitted structure;

[0016] One or more conductive paths are integrated into the three-dimensional space of the substrate through a digital braiding process to form at least three of the following interconnect structures:

[0017] a) Projection interlaced insulation structure: at least two conductive paths intersect on a projection perpendicular to the fabric plane, wherein a portion of the conductive path is embedded in the first surface layer and the other portion of the conductive path is embedded in the second surface layer. In the area where the projections intersect, a spacer layer acts as an electrical isolation medium to physically separate the two portions of the conductive path and achieve electrical insulation.

[0018] b) Interlayer transfer structure: At least one conductive path is configured to pass through a spacer layer from one surface layer and extend into the opposite surface layer to achieve cross-layer physical extension of the conductive path in the three-dimensional space of the fabric;

[0019] c) Three-dimensional packaging structure: At least one conductive path is woven and embedded inside the spacer layer, and is jointly encapsulated by the first and second surface layers, isolating it from the external environment and significantly improving environmental resistance and mechanical durability;

[0020] d) Electrode connection structure: at least one conductive path of conductive yarn is exposed on the fabric surface through programmed weaving to form an electrode interface for connection with external devices.

[0021] As a preferred technical solution:

[0022] In the fabric circuit described above, the composition and wiring topology of each conductive path are defined by a digital braiding program, including composite conductive paths formed by programmatically merging and braiding multiple conductive yarns, and / or independent conductive paths formed by programmatically separating and braiding multiple conductive yarns, which are insulated from each other. The composite conductive paths can reduce resistance, form electrical nodes, or reconstruct the circuit topology.

[0023] As described above, in a fabric circuit, the composite conductive path consists of multiple conductive yarns extending in parallel along the same path in the fabric and connected in parallel to form an integrated conductive structure that is electrically connected in parallel.

[0024] As described above, in a fabric circuit, the independent conductive paths that are insulated from each other are formed by multiple conductive yarns extending along their respective independent paths in the fabric, without physical contact and electrically isolated from each other.

[0025] In the fabric circuit described above, the first surface layer, the second surface layer, and the spacer layer of the substrate are all made of insulating fiber material, which is one or more of cotton, wool, silk, linen, polyester, nylon, acrylic, chlorofiber, acrylic chlorofiber, polypropylene, vinylon, spandex, glass fiber, aramid, polyimide fiber, acrylic pre-oxidized yarn, viscose, Tencel, Lyocell, Modal, and cellulose acetate.

[0026] In the fabric circuit described above, the conductive yarn is one or more of metal fiber, carbon-based conductive yarn, conductive polymer yarn, and metal-plated yarn, and the resistance of the conductive yarn is 0.01~15Ω / cm.

[0027] As described above, the knitted structure is one or more of the following: loop forming, yarn filling, loop gathering, weft insertion, or warp insertion.

[0028] In one type of fabric circuit as described above, the conductive yarns in the electrode connection structure are exposed to the fabric surface through a knitted structure consisting of loops, intarsia, or reverse-stitched yarns.

[0029] In the fabric circuit described above, at least one of the three interconnect structures is an electrode connection structure.

[0030] The present invention also provides a method for preparing a fabric circuit as described above, comprising the following steps:

[0031] Step S1: Perform structural design of the fabric circuit, determine the type, quantity and location of the interconnection structure, and determine the composition and wiring topology of each conductive path;

[0032] Step S2: Program generation: Convert the structural design data of the fabric circuit into a digital knitting program that drives the double needle bed weft knitting machine. This program defines the feeding sequence of all yarn feeders, needle actions and knitting structure.

[0033] Step S3: Integrated Weaving: Execute a digital weaving program to dynamically integrate circuitry while weaving the substrate, wherein:

[0034] When weaving the projection interlaced insulation structure, conductive yarns are woven into the upper and lower surface layers, and insulating yarns are woven into the spacer layer, so that at least two conductive paths intersect on the projection perpendicular to the fabric plane. Among them, a part of the conductive path is embedded in the first surface layer, and the other part of the conductive path is embedded in the second surface layer. In the projection intersection area, the spacer layer acts as an electrical isolation medium to physically separate the two parts of the conductive path and achieve electrical insulation.

[0035] When weaving the interlayer transfer structure, the conductive yarn is controlled to precisely pass through the spacer layer, so that at least one conductive path passes through the spacer layer from one surface layer and extends and embeds into the opposite surface layer, so as to realize the cross-layer physical extension of the conductive path in the three-dimensional space of the fabric.

[0036] When weaving a three-dimensional encapsulation structure, the conductive yarn is controlled to be embedded inside the spacer layer in a weft-insertion, warp-insertion, or loop-tuck manner, so that at least one conductive path is woven and embedded inside the spacer layer, and is encapsulated by the first and second surface layers to isolate it from the external environment.

[0037] When weaving the electrode connection structure, the conductive yarn is exposed on the fabric surface by looping, inlaying, or reverse yarn addition, so that the conductive yarn of at least one conductive path is exposed on the fabric surface by programmed weaving to form an electrode interface for connection with external devices.

[0038] When weaving a composite conductive path formed by the programmed merging and weaving of multiple conductive yarns, multiple yarn nozzles are controlled to weave multiple conductive yarns together at the same position, so that the multiple conductive yarns are collinear.

[0039] When weaving independent conductive paths that are insulated from each other and formed by the programmed separation and weaving of multiple conductive yarns, multiple yarn nozzles are controlled to weave the multiple conductive yarns at different positions, so that the conductive yarns are separated from each other.

[0040] The present invention also provides an electronic system including one or more external devices and a fabric circuit as described above;

[0041] The external device and the fabric circuit are electrically connected by an electrode connection structure, and the two are integrated into a fully functional electronic system.

[0042] As a preferred technical solution:

[0043] In the electronic system described above, the external device is one or more of the following:

[0044] a) Power module for supplying power to the fabric circuitry;

[0045] b) A processing control module for processing signals transmitted through the fabric circuitry and / or controlling functions performed through the fabric circuitry;

[0046] c) Communication module, used to enable the electronic system to communicate data with external networks or other devices;

[0047] d) Sensor module, used to sense environmental or physiological signals and transmit the signals to the processing and control module through fabric circuitry;

[0048] e) Actuator module, including LEDs, displays, heating elements or vibration motors, driven by fabric circuitry.

[0049] In the electronic system described above, external devices are electrically connected to the electrode connection structure of the fabric circuit through an electrical connection structure, wherein the electrical connection structure is one or more of a solder joint, a magnetic connector, a zero insertion / extraction force connector, or a snap connector.

[0050] Beneficial effects:

[0051] (1) This invention creatively utilizes the upper and lower double layers of spacer fabric through a projection interlaced insulation structure to weave the intersecting conductive paths into different surface layers, using the spacer layer as an insulator, fundamentally solving the problem of short circuits caused by the crossover of conductive paths within a single layer of fabric. No external insulation layer or jumper is required, greatly improving wiring density and circuit design complexity.

[0052] (2) This invention achieves programmed extension and precise cross-layering of conductive paths in the fabric thickness direction through an interlayer transfer structure, completely breaking through the dimensional limitations of planar fabric wiring. This structure provides a real and controllable three-dimensional wiring space for the circuit, making it possible to integrate complex interconnect architectures similar to multi-layer PCBs (printed circuit boards) within a single piece of fabric.

[0053] (3) Based on the multi-yarn digital control technology, the present invention can dynamically configure the connection state (merging or separating) and spatial position of the conductive path during weaving. This not only realizes the real-time reconstruction of the circuit topology, but also actively adjusts the key electrical properties of the local circuit such as resistance and current carrying capacity by merging multiple yarns, thus upgrading the traditionally fixed-function circuit fabric into a fabric circuit platform that can be quickly customized and has a flexible and varied topology.

[0054] (4) Through a three-dimensional encapsulation structure, the present invention can weave and completely encapsulate critical or sensitive conductive path segments inside the spacer layer by means of weft padding, warp padding, or tufting, with the upper and lower insulating surfaces forming a protective encapsulation interface. This structure significantly improves the circuit's resistance to mechanical and environmental stresses such as bending, friction, washing, and oxidation, and greatly enhances its long-term reliability.

[0055] (5) The present invention can form a stable and reliable electrical contact area directly on the fabric surface through a variety of programmable electrode connection structures (such as loop exposure and reverse yarn addition), which greatly simplifies the integration with external components or equipment.

[0056] (6) Based on weft knitting technology, the entire circuit has excellent flexibility, stretchability and breathability, which perfectly meets the needs of wearable devices for comfort and dynamic fit.

[0057] (7) This invention realizes the improvement from "functional fabric" to "fabric PCB platform". Unlike the dedicated fabric circuits with fixed functions in the prior art, this invention constructs a universal, programmable three-dimensional interconnect carrier, which can flexibly integrate diverse electronic functions such as power supply, processor, sensor, communication module, actuator, etc., just like a printed circuit board, and quickly customize fully flexible electronic systems to meet the needs of different application scenarios, greatly expanding the application boundaries and design freedom of fabric circuits. Attached Figure Description

[0058] Figure 1This is a functional block diagram of an electronic system according to the present invention;

[0059] Figure 2 This is a schematic diagram of the integrally formed insulating weft-knitted spacer fabric of the present invention.

[0060] Figure 3 This is a schematic diagram of the internal circuit of the conductive path configuration in the fabric circuit of the present invention.

[0061] Figure 4 This is an overall schematic diagram of the three-dimensional interconnected fabric circuit of the present invention;

[0062] Figure 5 This is a cross-sectional schematic diagram of the projected interlaced insulation structure of the present invention;

[0063] Figure 6 This is an exploded view of the projected interlaced insulation structure of the present invention;

[0064] Figure 7 This is a cross-sectional schematic diagram of the interlayer transfer structure of the present invention;

[0065] Figure 8 This is a cross-sectional schematic diagram of the three-dimensional encapsulation structure achieved by the loop-knitted structure of the present invention;

[0066] Figure 9 This is a cross-sectional schematic diagram of the three-dimensional encapsulation structure achieved by the weft-inserted knitted structure of the present invention;

[0067] Figure 10 This is a cross-sectional schematic diagram of the three-dimensional encapsulation structure achieved by the lining knitted structure of the present invention;

[0068] Figure 11 This is a schematic diagram of the electrode connection structure achieved by the present invention through a looped knitting structure;

[0069] Figure 12 This is a schematic diagram of the electrode connection structure achieved by the present invention through an intarsia knitted structure;

[0070] Figure 13 This is a schematic diagram of the electrode connection structure achieved by the present invention through a knitted structure with reverse yarn addition;

[0071] Figure 14 This is a schematic diagram of the structure of the present invention when both conductive paths are located on the same surface layer and are in an independent state.

[0072] Figure 15 This is a schematic diagram of the structure of the present invention when both conductive paths are located in the spacer layer and are in an independent state.

[0073] Figure 16 This is a schematic diagram of the structure of the present invention when the two conductive paths are located on different surfaces and are in an independent state.

[0074] Figure 17 This is a schematic diagram of the structure of the present invention when the two conductive paths are located in the surface layer and the spacer layer respectively and are in an independent state;

[0075] Figure 18 This is a schematic diagram of the structure of the present invention where the conductive paths are merged into a composite path on the fabric surface layer;

[0076] Figure 19 This is a schematic diagram of the structure of the present invention where the conductive paths are merged into a composite path in the spacer layer;

[0077] Figure 20 This is a flowchart illustrating the fabrication process of the fabric circuit of the present invention.

[0078] Among them, 11 is the first surface layer, 12 is the second surface layer, 13 is the spacer layer, 20 is the conductive path, 100 is the fabric circuit, 110 is the projected interlaced insulation structure, 120 is the interlayer transfer structure, 130 is the three-dimensional encapsulation structure, 140 is the electrode connection structure, 141 is the electrical contact point, 150 is the independent conductive path, and 160 is the composite conductive path. Detailed Implementation

[0079] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0080] An electronic system, such as Figure 1 As shown, it includes one or more external devices and a fabric circuit 100;

[0081] A fabric circuit, such as Figures 2-4 As shown, it includes a substrate and one or more conductive paths 20;

[0082] The base is an integrally formed insulating weft-knitted spacer fabric, including a first surface layer 11, a second surface layer 12, and a spacer layer 13 connected between the first surface layer 11 and the second surface layer 12.

[0083] The first surface layer 11, the second surface layer 12, and the spacer layer 13 are all made of insulating fiber materials, which are one or more of the following: cotton, wool, silk, linen, polyester, nylon, acrylic, chlorofiber, acrylic chlorofiber, polypropylene, vinylon, spandex, glass fiber, aramid, polyimide fiber, acrylic pre-oxidized yarn, viscose, Tencel, Lyocell, Modal, and cellulose acetate.

[0084] Each conductive path 20 is formed by one or more conductive yarns embedded in the substrate through a knitted structure; the conductive yarn is one or more of metal fiber, carbon-based conductive yarn, conductive polymer yarn and metal-plated yarn, and the resistance of the conductive yarn is 0.01~15Ω / cm; the knitted structure is one or more of loop forming, yarn filling, loop gathering, weft filling or warp filling.

[0085] One or more conductive paths 20 are integrated into at least three interconnect structures in the three-dimensional space of the substrate through a digital braiding process, one of which is an electrode connection structure, such as... Figure 4 As shown, the interconnection structures are as follows:

[0086] The projected interlaced insulation structure 110 is used to resolve the intersection conflicts of the conductive paths 20 on the plane projection, realizing cross wiring without jumpers or additional insulation layers within the fabric. Its structure is as follows: Figure 5 , Figure 6 As shown, at least two conductive paths 20 intersect on a projection perpendicular to the fabric plane. One part of the conductive path 20 is embedded in the first surface layer 11, and the other part of the conductive path 20 is embedded in the second surface layer 12. In the intersecting region of the projection, the spacer layer 13 acts as an electrical isolation medium to physically separate the two parts of the conductive path 20 and achieve electrical insulation.

[0087] Interlayer transfer structure 120 is used to realize interlayer transfer of circuits in the thickness direction, and its structure is as follows: Figure 7 As shown, at least one conductive path 20 is configured to pass through the spacer layer 13 from the first surface layer 11 and extend into the opposite second surface layer 12, thereby forming a continuous conductive path 20 through the upper and lower surface layers of the fabric.

[0088] The three-dimensional encapsulation structure 130 is used for internal protection of the circuit. Its structure is as follows: at least one conductive path 20 is woven and embedded inside the spacer layer 13, and is jointly encapsulated by the first surface layer 11 and the second surface layer 12. The following is an example of a knitted structure with loops, weft padding, and warp padding:

[0089] The knitted structure is a tucked loop: such as Figure 8 As shown, the conductive path 20 is used as a looped yarn, which is alternately looped between the first surface layer 11 and the second surface layer 12 and encapsulated by the first surface layer 11 and the second surface layer 12.

[0090] Knitted structures with weft inserts: such as Figure 9 As shown, the conductive path 20 is introduced as a weft yarn and fixed to the spacer layer 13, and is encapsulated by the first surface layer 11 and the second surface layer 12.

[0091] The knitted structure is a warp-insertion structure: such as Figure 10As shown, the conductive path 20 is introduced as a backing warp and fixed to the spacer layer 13, and is encapsulated by the first surface layer 11 and the second surface layer 12.

[0092] Electrode connection structure 140 is used to form electrical contact points 141 for connection with external devices on the surface of insulating weft-knitted spacer fabric. Its structure is as follows: at least one conductive path 20 of conductive yarn is exposed on the fabric surface through programmed knitting to form an electrode interface for connection with external devices; wherein the conductive yarn is exposed on the fabric surface through a knitted structure of loop forming, intarsia, or reverse yarn addition, as detailed below:

[0093] The knitted structure is in loops: such as Figure 11 As shown, in the electrode region, the insulating yarn of the first surface layer 11 is woven into the second surface layer 12, thereby forming a gap in the first surface layer in the electrode region. The conductive path 20 is woven in loops in the first surface layer 11 and in loops in the second surface layer 12, so that the conductive path 20 is exposed on the surface of the first surface layer 11 of the fabric, forming an electrical contact point 141.

[0094] The knitted structure is intarsia: such as Figure 12 As shown, in the electrode region, the insulating yarn of the first surface layer 11 is woven into the second surface layer 12, thereby forming a gap in the first surface layer of the electrode region. The conductive path 20 is alternately looped between the first surface layer 11 and the second surface layer 12 to ensure the continuity of the conductive path 20. Another conductive yarn is woven in a loop structure on the surface of the electrode region to form an electrical contact point 141 exposed on the surface of the first surface layer 11 of the fabric.

[0095] The knitted structure is a reverse yarn filling: such as Figure 13 As shown, in the non-electrode area of ​​the first surface layer 11 of the fabric, the conductive path 20 and the insulating yarn of the first surface layer 11 are woven together using a yarn-adding structure, and the conductive path 20 is located in the inner layer and is covered by the insulating yarn; in the electrode area, the yarn nozzle position is exchanged using a reverse yarn-adding technique, so that the conductive path 20 is transferred to the outer layer for weaving, while the insulating yarn is transferred to the inner layer, thereby exposing the conductive path 20 to the surface of the first surface layer 11 of the fabric, forming an electrical contact point 141;

[0096] The composition and wiring topology of each conductive path 20 are defined by a digital braiding program, including composite conductive paths formed by programmatically merging and braiding multiple conductive yarns, and / or independent conductive paths formed by programmatically separating and braiding multiple conductive yarns, which are insulated from each other.

[0097] like Figures 14-17 As shown, the independent conductive paths 150, formed by the programmed separation and weaving of multiple conductive yarns and insulated from each other, are formed by feeding multiple conductive yarns into different knitting needles through multiple yarn feeders and weaving them separately; among them, according to the spatial position of the conductive path 20, there are the following five cases:

[0098] (I) If Figure 14 As shown, both conductive paths 20 are located in the first surface layer 11 or the second surface layer 12, and the two conductive paths 20 do not intersect.

[0099] (II) As Figure 15 As shown, both conductive paths 20 are located in the spacer layer 13, and the two conductive paths 20 do not intersect.

[0100] (III) such as Figure 16 As shown, the two conductive paths 20 are located on the first surface layer 11 and the second surface layer 12, respectively, and the vertical projections of the two conductive paths 20 do not intersect.

[0101] (IV) such as Figure 17 As shown, one conductive path 20 is located in the first surface layer 11 or the second surface layer 12, and the other conductive path 20 is located in the spacer layer 13. The vertical projections of the two conductive paths 20 do not intersect.

[0102] (V) Two conductive paths 20 are located on the first surface layer 11 and the second surface layer 12, respectively. The perpendicular projections of the two conductive paths 20 intersect, and their structure is as follows: Figure 5 As shown, this is the projected interlaced insulation structure 110.

[0103] like Figure 18 , Figure 19 As shown, the composite conductive path 160, formed by the programmed merging and weaving of multiple conductive yarns, is achieved by feeding multiple conductive yarns into the same coil at the same coil position using multiple yarn feeders, thus enabling the multiple yarns to form a single coil. The merging of multiple conductive yarns can be achieved based on their initial spatial positions using the following programming strategy:

[0104] Same-layer merging: When the conductive paths 20 that need to be merged are all located on the same surface layer or on the spacer layer 13, the different conductive yarns are directly led to the same position for common coiling at the target position, so that the two originally separate paths are merged into a composite path here, realizing real-time reconstruction of the circuit topology.

[0105] Cross-layer merging: When the conductive paths 20 to be merged are located in different layers (e.g., one in the first surface layer 11 or the second surface layer 12, and the other in the spacer layer 13; or the conductive paths 20 are in the first surface layer 11 and the second surface layer 12 respectively), the merging operation is performed in two steps:

[0106] 1) By adjusting the interlayer transfer structure 120 or the braided structure, one of the conductive paths 20 can be transferred or extended in space to the layer where another conductive path 20 is located;

[0107] 2) When two paths converge in the same local space, a same-level merging operation is performed to achieve electrical connection;

[0108] It should be noted that, Figure 18 , Figure 19 The multiple conductive yarns shown sharing a loop at the same coil is merely an exemplary implementation of merging and weaving. In other embodiments of the invention, the merging of multiple conductive yarns can also be achieved through one or more of the following knitting structures: multiple conductive yarns forming the same loop at the same location; multiple conductive yarns being introduced side-by-side into the same weft direction of the fabric, extending side-by-side and in contact with each other; multiple conductive yarns being introduced side-by-side into the same warp direction of the fabric, extending side-by-side and in contact with each other; or, multiple conductive yarns being overlapped in the same area of ​​the fabric by adding yarn, forming an electrical parallel connection. All of the above methods enable multiple conductive yarns to run parallel along the same path in the fabric and form an electrical connection, thereby increasing the cross-section and reducing the resistance of the composite conductive path. Those skilled in the art can flexibly select one or more combinations of the above merging methods according to actual process and performance requirements, or use other knitting structures to electrically connect multiple conductive yarns without departing from the protection scope of the invention.

[0109] The external device is one or more of the following:

[0110] a) Power module for supplying power to the fabric circuitry;

[0111] b) A processing control module for processing signals transmitted through the fabric circuitry and / or controlling functions performed through the fabric circuitry;

[0112] c) Communication module, used to enable the electronic system to communicate data with external networks or other devices;

[0113] d) Sensor module, used to sense environmental or physiological signals and transmit the signals to the processing and control module through fabric circuitry;

[0114] e) An actuator module, comprising LEDs, displays, heating elements, or vibration motors, driven by fabric circuitry;

[0115] External devices are electrically connected to the electrode connection structure of the fabric circuit through an electrical connection structure, thereby enabling convenient and reliable system integration with power modules, processing control modules, communication modules, sensor modules, and actuator modules; the electrical connection structure is one or more of the following: soldering, magnetic connectors, zero insertion / extraction force connectors, and snap connectors.

[0116] The above-mentioned method for fabricating a fabric circuit, such as Figure 20 As shown, the steps are as follows:

[0117] Step S1: Use electronic design automation (EDA) tools to design the fabric circuit structure, determine the type, quantity and location of interconnect structures, and determine the composition and wiring topology of each conductive path;

[0118] Step S2: Program generation: Using dedicated knitting pattern making software, the structural design data of the fabric circuit is converted into a digital knitting program that drives the double needle bed weft knitting machine. This program defines the feeding sequence of all yarn feeders, needle actions, and knitting structure.

[0119] Step S3: Integrated weaving: Execute the digital weaving program.

[0120] To verify that the above electronic system can meet the needs of different scenarios, a specific case study is provided below:

[0121] Example 1

[0122] Using the above-mentioned electronic system, a flexible fabric display driving backplate capable of driving an 8-pixel × 8-pixel LED matrix is ​​prepared, which can be directly used as the display area of ​​smart clothing, the driving layer of flexible decorative fabric, or the display substrate of rollable smart devices.

[0123] The electronic system consists of fabric circuitry, a power supply module, a processing and control module, a communication module, and an actuator module.

[0124] The power module is a low-voltage DC power supply (5V / 1A) that supplies power to the entire system;

[0125] The processing and control module is an LED driver controller (model: STM32F103).

[0126] The communication module is a Bluetooth module (model: HC-05), used to receive external control commands and transmit display data;

[0127] The actuator module is an 8×8 LED array;

[0128] The low-voltage DC power supply is connected to the electrode connection structure of the fabric circuit through a snap connector, and the LED driver controller, Bluetooth module and LED array are respectively connected to the electrode connection structure of the fabric circuit by soldering.

[0129] The fabric circuit is prepared using one of the above-mentioned fabric circuit preparation methods. The insulating fiber material of the first surface layer, the second surface layer, and the spacer layer of the prepared fabric circuit is polyester with a linear density of 600D.

[0130] The conductive yarn is made of silver-copper alloy wire, and its resistance is 0.01Ω / cm.

[0131] The conductive paths are integrated into an interconnect structure within the three-dimensional space of the substrate through a digital braiding process, as shown below:

[0132] Three-dimensional packaging structure: To reduce bus resistance and ensure uniform power supply to all LEDs on the board, four silver-copper alloy wires are first programmatically merged into two composite conductive paths during weaving, serving as global low-impedance buses for VCC (power supply) and GND (ground), respectively. Then, one of the composite conductive paths is introduced as a weft yarn and fixed to the spacer layer, and encapsulated by the first and second surface layers. The other composite conductive path is introduced as a warp yarn and fixed to the spacer layer, and encapsulated by the first and second surface layers. This provides comprehensive protection from the upper and lower insulating layers, greatly improving its mechanical reliability against repeated bending and curling.

[0133] Interlayer transfer structure and projected staggered insulation structure: To construct an 8-pixel × 8-pixel LED array, 8 row lines and 8 column lines are required (each row line and column line is an independent conductive path formed by a single conductive yarn through programmed weaving, and insulated from each other). First, using the interlayer transfer structure, the conductive path of the row line located in the spacer layer is precisely transferred downwards to the first surface layer at the pixel position. At the transferred position, through the design logic of the projected staggered insulation structure, it is ensured that the transferred row line and the column line located in the second surface layer are insulated and isolated at the intersection (the spacer layer acts as the insulating medium). The actual electrical connection occurs at the electrode pads specially designed for this pixel.

[0134] Electrode connection structure: At each pixel location, an electrode connection structure is used to create a pad for surface mounting. Specifically, at the predetermined LED mounting point, the program controls the insulation yarns of the first and second surface layers to temporarily transfer to the same surface layer for weaving. At this time, two independent conductive yarns (one from the column line and the other from the row line transferred here through the interlayer) are guided to this area and exposed on the fabric surface to participate in loop weaving, thereby forming two mutually insulated and exposed conductive coils, which serve as pads connecting the LED anode and cathode respectively. The pads formed in this way have a smooth surface, a strong bond, and good solderability.

[0135] The electronic system described above can stably drive 64 5730-sized surface mount LEDs. After the fabric backplate is repeatedly bent (R=5mm) 1000 times, all electrical connections remain intact, the LEDs do not fall off, and the display function is normal in the curled state.

[0136] Example 2

[0137] An intelligent health cushion system with an integrated pressure sensing array was prepared using the above-mentioned electronic system. By constructing a 500mm×500mm fabric circuit as the core sensing layer of the intelligent cushion, it was laid under the cushion comfort layer (12mm thick memory foam) to achieve imperceptible body pressure distribution monitoring and sitting posture recognition.

[0138] The electronic system consists of fabric circuitry, a power supply module, a processing and control module, a communication module, and a sensor module.

[0139] The power module is a low-voltage DC power supply (5V / 1A) that supplies power to the entire system;

[0140] The processing and control module is an STM32F103 main control chip, used to acquire pressure sensing signals and interact with the communication module.

[0141] The communication module is a Bluetooth module (model: HC-05), used to transmit body pressure distribution data to the host computer.

[0142] The sensor module consists of 64 commercial thin-film piezoresistive sensors (model: FlexiForce A201-25, sensing area diameter 9.7mm, thickness 0.203mm, pressure range: 0~112.5N (approximately 0~11.5kg), sensitivity ≥0.1N), forming an 8×8 pressure sensing array for sensing body pressure distribution;

[0143] The low-voltage DC power supply is electrically connected to the electrode connection structure of the fabric circuit through a snap connector; the STM32F103 main control chip and the Bluetooth module are respectively connected to the electrode connection structure of the fabric circuit through soldering.

[0144] Sensor module: The two pins of each sensor module are electrically connected to the corresponding electrode contacts on the fabric circuit (leaded out by transverse electrode lines and longitudinal electrode lines) through conductive adhesive, and the sensor is fixed to the fabric surface;

[0145] The fabric circuit is fabricated using one of the above-mentioned fabric circuit fabrication methods, and its substrate is a double-sided weft-knitted spacer fabric, with the following specific parameters:

[0146] Both the first and second layers (top and bottom) are woven from polyester filaments with a linear density of 600D as the insulating fiber material, and the spacer layer is made of polyester monofilaments with a diameter of 0.1mm and a spacing height of 3mm.

[0147] The conductive yarn is silver-plated nylon, manufactured by Shandong Boyin Surface Functional Materials Co., Ltd., with a linear density of 70D and a resistance of 15Ω / cm, and is used to form the electrode wires of the sensor array.

[0148] In an 8×8 pressure sensing array constructed within a single piece of fabric, conductive paths are integrated into the following interconnect structure in the three-dimensional space of the substrate through a digital weaving process:

[0149] 3D packaging structure: To protect long-distance signal lines, the 8 column electrode leads and 8 row electrode leads (leading from the sensor array to the edge connector) are embedded inside the spacer layer using weft and warp padding packaging.

[0150] Interlayer transfer structure: In order to construct electrode contacts, the transverse electrode line is precisely transferred from the first surface layer through the spacer layer to the second surface layer through the interlayer transfer structure, and the longitudinal electrode lines of the second surface layer are all converged to the same surface layer of the fabric (second surface layer).

[0151] Projection interlaced insulation structure: At each projection intersection of the transverse electrode line and the longitudinal electrode line (64 intersections in total), the two are located in the first surface layer and the second surface layer respectively. A spacer layer (3mm thick) made of polyester monofilament is used as a built-in insulating medium to ensure electrical isolation between the electrode lines and avoid short circuits.

[0152] Electrode connection structure: Sensing unit pads and edge connection pads are formed by exposing them in a ring for connecting external devices, as detailed below:

[0153] Sensor unit pads: At each intersection, two conductive pads that are insulated from each other are formed using an electrode connection structure, which connect the transverse electrode line and the longitudinal electrode line respectively. Then, the two pins of the thin-film piezoresistive sensor are attached to the pads with conductive adhesive, thereby realizing the electrical connection and mechanical fixation between the sensor and the fabric circuit. The knitted structure used to expose the conductive yarn on the fabric surface is looped, and the center-to-center distance between adjacent sensors is 50mm.

[0154] Edge connection pads: At the edge of the fabric, eight row electrode conductive pads and eight column electrode conductive pads are formed using an electrode connection structure, and are connected to external processing control modules, power supply and communication modules through snap connectors; wherein, the knitting structure used to expose the conductive yarn to the fabric surface is looped.

[0155] A concealed electrical box (60mm×60mm×20mm) is located on the side of the seat cushion, integrating the following external devices: a low-voltage DC power supply (5V / 1A), an STM32F103 main control chip (processing and control module), and a Bluetooth module. The sensor modules are located under the comfort layer of the seat cushion and are connected to the main control chip in the electrical box via electrode pads on the fabric circuitry.

[0156] The electronic system prepared above can stably detect the body pressure distribution at 64 sensing points; after the fabric circuit is repeatedly bent (R=5mm) 1000 times, there are no open circuits or short circuits in all conductive paths, and the sensor is firmly connected to the pad.

[0157] The fabric circuits prepared above can also be used directly in car seats or office chairs.

[0158] The above embodiments are merely several typical applications of the present invention, intended to help understand the core principles of the present invention, and do not constitute a limitation on the scope of protection. Those skilled in the art should understand that, without departing from the core concept of the present invention of "constructing a programmable three-dimensional conductive network based on weft-knitted spacer fabric," more types and more complex fully flexible electronic fabrics can be derived through reasonable adjustments and combinations of the knitting program, yarn materials, knitting structure, and external devices, and all of these fall within the scope of protection of the present invention.

[0159] In the description of this application, it should be noted that the terms "first layer," "second layer," "transverse," and "longitudinal," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The yarn direction, coil structure, and interlayer relationship in the accompanying drawings are schematic representations, and the actual weaving structure can be adjusted according to process requirements.

Claims

1. A fabric circuit, characterized in that, Includes a substrate and one or more conductive paths; The base is an integrally formed insulating weft-knitted spacer fabric, including a first surface layer, a second surface layer, and a spacer layer connected between the first surface layer and the second surface layer. Each conductive path is formed by one or more conductive yarns embedded in the substrate through a knitted structure; One or more conductive paths are integrated into the three-dimensional space of the substrate through a digital braiding process to form at least three of the following interconnect structures: a) Projection interlaced insulation structure: at least two conductive paths intersect on a projection perpendicular to the fabric plane, wherein a portion of the conductive path is embedded in the first surface layer and the other portion of the conductive path is embedded in the second surface layer. In the area where the projections intersect, a spacer layer acts as an electrical isolation medium to physically separate the two portions of the conductive path and achieve electrical insulation. b) Interlayer transfer structure: at least one conductive path is configured to pass through a spacer layer from one surface layer and extend into the opposite surface layer; c) Three-dimensional encapsulation structure: at least one conductive path is woven and embedded inside the spacer layer, and is jointly encapsulated by the first surface layer and the second surface layer; d) Electrode connection structure: at least one conductive path of conductive yarn is exposed on the fabric surface through programmed weaving to form an electrode interface for connection with external devices.

2. The fabric circuit according to claim 1, characterized in that, The composition and wiring topology of each conductive path are defined by a digital braiding program, including composite conductive paths formed by the programmed merging and braiding of multiple conductive yarns, and / or independent conductive paths formed by the programmed separation and braiding of multiple conductive yarns, which are insulated from each other.

3. A fabric circuit according to claim 2, characterized in that, The composite conductive path consists of multiple conductive yarns extending in parallel along the same path in the fabric and connected in parallel to form an integrated conductive structure that is electrically connected in parallel, thereby increasing the cross-section and reducing the resistance.

4. A fabric circuit according to claim 2, characterized in that, The independent conductive paths that are insulated from each other consist of multiple conductive yarns extending along their own independent paths in the fabric, with no physical contact and electrical isolation between them.

5. A fabric circuit according to claim 1, characterized in that, The first surface layer, the second surface layer, and the spacer layer of the substrate are all made of insulating fiber material, which is one or more of the following: cotton, wool, silk, linen, polyester, nylon, acrylic, chlorofiber, acrylic chlorofiber, polypropylene, vinylon, spandex, glass fiber, aramid, polyimide fiber, acrylic pre-oxidized yarn, viscose, Tencel, Lyocell, Modal, and cellulose acetate.

6. A fabric circuit according to claim 1, characterized in that, The conductive yarn is one or more of the following: metal fiber, carbon-based conductive yarn, conductive polymer yarn, and metal-plated yarn. The resistance of the conductive yarn is 0.01~15Ω / cm.

7. A fabric circuit according to claim 1, characterized in that, The knitted structure is one or more of the following: looping, yarn layering, tucking, weft layering, or warp layering.

8. A fabric circuit according to claim 1, characterized in that, The conductive yarns in the electrode connection structure are exposed to the fabric surface through a knitted structure with loops, inlays, or reverse yarn addition.

9. A fabric circuit according to any one of claims 1 to 8, characterized in that, At least one of the three interconnect structures is an electrode connection structure.

10. A method for preparing a fabric circuit as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Step S1: Perform structural design of the fabric circuit, determine the type, quantity and location of the interconnection structure, and determine the composition and wiring topology of each conductive path; Step S2: Program generation: Convert the structural design data of the fabric circuit into a digital knitting program that drives the double needle bed weft knitting machine. This program defines the feeding sequence of all yarn feeders, needle actions and knitting structure. Step S3: Integrated weaving: Execute the digital weaving program.

11. An electronic system, characterized in that, Includes one or more external devices and a fabric circuit as described in claim 9; The external device is electrically connected to the electrode connection structure of the fabric circuit.

12. An electronic system according to claim 11, characterized in that, The external device is one or more of the following: a) Power module for supplying power to the fabric circuitry; b) A processing control module for processing signals transmitted through the fabric circuitry and / or controlling functions performed through the fabric circuitry; c) Communication module, used to enable the electronic system to communicate data with external networks or other devices; d) Sensor module, used to sense environmental or physiological signals and transmit the signals to the processing and control module through fabric circuitry; e) Actuator module, including LEDs, displays, heating elements or vibration motors, driven by fabric circuitry.

13. An electronic system according to claim 11, characterized in that, External devices are electrically connected to the electrode connection structure of the fabric circuit through an electrical connection structure, wherein the electrical connection structure is one or more of a soldering, magnetic connector, zero insertion / extraction force connector or snap connector.

Images