A vehicle-mounted FPC matrix jumper structure, a manufacturing method and a conduction test method

Abstract

The application relates to a vehicle-mounted FPC matrix jumper structure, a manufacturing process and a conduction test method, and relates to the technical field of printed circuits. The FPC matrix jumper structure comprises a flexible substrate, the flexible substrate is provided with a conductive circuit layer, the conductive circuit layer comprises a conductive network and a plurality of cross circuits, the cross circuits comprise starting circuits and terminal circuits, the starting circuits and the terminal circuits are arranged at intervals and distributed in the conductive network, and the starting circuits and the terminal circuits are electrically connected with the conductive network; the conductive silver paste layer comprises a plurality of conductive silver pieces, one end of the conductive silver piece is connected with a corresponding starting circuit, and the other end is connected with a corresponding terminal circuit; a plurality of grid holes are formed in the conductive silver piece, and the plurality of grid holes are arranged in a matrix; the insulating medium layer comprises a plurality of cross-line isolation pieces, and the cross-line isolation pieces are arranged on the side of the corresponding conductive silver piece facing the flexible substrate. The application can improve the long-term operation reliability of the FPC under winding and dynamic bending working conditions.

Description

Technical Field

[0001] This application relates to the technical field of printed circuits, and in particular to an automotive FPC matrix jumper structure, manufacturing method, and continuity testing method. Background Technology

[0002] With the rapid development of automotive electronics technology, intelligent automotive panels are widely used, such as illuminated door panels and panoramic sunroofs. To achieve complex dynamic display effects, it is typically necessary to densely arrange tens of thousands of LED beads on a flexible printed circuit board (FPC) and construct a crisscrossing matrix driving circuit. When performing high-density matrix wiring on a single-layer FPC plane, the crossing of different network lines is inevitable. To prevent electrical short circuits between crossing lines, a jumper structure must be used in the circuit topology to achieve three-dimensional crossing of one of the crossing lines.

[0003] Currently, there are two main technical methods in the industry for achieving FPC circuit crossing: the first is to use double-layer or multi-layer FPC boards, achieving circuit avoidance through interlayer vias. The second is to use a single-layer FPC board, using surface mount technology (SMT) to solder physical jumper devices, such as 0Ω resistors or copper sheets, at the circuit crossing points. Because the lamination process of double-layer FPC in the first method is complex, has a low yield rate, and involves high substrate costs, the single-layer FPC with surface mount physical devices in the second method has become a more common choice.

[0004] Regarding the aforementioned technologies, the internal assembly space of automotive smart panels is typically quite small and irregularly curved, requiring the FPC to withstand winding and bending during actual assembly and long-term use. However, existing physical jumper devices have a certain thickness and rigidity. When the FPC undergoes local bending, the physical jumper device's own rigidity cannot match the FPC's deformation curvature, causing bending stress to concentrate at the solder joints at both ends of the physical jumper device. Furthermore, after prolonged winding or bending, stress concentration can easily occur at the solder joints at both ends of the physical jumper device, leading to fatigue fracture of the corresponding solder joints, peeling of the bottom copper foil circuitry from the substrate, and even the sharp edges of the physical jumper device tearing the flexible substrate, thus reducing the long-term operational reliability of the FPC. Summary of the Invention

[0005] This application provides an on-board FPC matrix jumper structure, manufacturing method, and continuity testing method, the purpose of which is to improve the deformation compliance of FPC under winding and dynamic bending conditions, thereby improving the long-term operational reliability of FPC under winding and dynamic bending conditions.

[0006] Firstly, the vehicle-mounted FPC matrix jumper structure provided in this application adopts the following technical solution: A vehicle-mounted FPC matrix jumper structure includes: a flexible substrate with a conductive circuit layer, the conductive circuit layer including a conductive network and a plurality of bridging circuits, each bridging circuit including a starting circuit and an ending circuit, the starting circuit and the ending circuit being spaced apart and distributed in the conductive network, both the starting circuit and the ending circuit being electrically connected to the conductive network; a conductive silver paste layer including a plurality of conductive silver sheets, each conductive silver sheet corresponding to one of the bridging circuits, one end of each conductive silver sheet being connected to the corresponding starting circuit and the other end being connected to the corresponding ending circuit; each conductive silver sheet having a plurality of grid holes arranged in a matrix; and an insulating dielectric layer including a plurality of bridging isolation sheets, each bridging isolation sheet corresponding to one of the conductive silver sheets, the bridging isolation sheets being disposed on the side of the corresponding conductive silver sheet facing the flexible substrate.

[0007] By adopting the above technical solution, the cross-line isolation sheet is disposed on the side of the conductive silver sheet facing the flexible substrate, so that the cross-line isolation sheet forms electrical isolation between the conductive silver sheet and the conductive network below.

[0008] Conductive silver sheets are printed in thin film form across the jumper isolation sheet, electrically connecting the spaced starting and ending circuits. This allows for a three-dimensional conductive network to be formed on a single-layer flexible substrate, thus fulfilling the function of the jumper structure.

[0009] Based on this, the printed conductive silver sheet exhibits a flexible film shape, which can bend and deform along with the flexible substrate. This can overcome the physical defect of stress concentration caused by the inherent rigidity of physical jumper devices in the prior art.

[0010] Furthermore, the matrix arrangement of several grid holes on the conductive silver sheet discretizes the originally continuous large-area conductive silver paste coating into multiple short-span silver paste ribs. This not only reduces the overall silver paste coverage area and continuous stiffness of the conductive silver sheet, thus improving its bending compliance, but also weakens the local bending strain borne by each silver paste rib when the flexible substrate undergoes dynamic bending or winding.

[0011] This design reduces the risk of overall brittleness or peeling of the conductive silver sheet due to excessive stiffness, thereby improving the deformation compliance and long-term operational reliability of the FPC under small curvature winding and dynamic bending conditions.

[0012] Optionally, the conductive silver sheet includes two spaced-apart connecting disks, each corresponding to a starting circuit and an ending circuit, and the connecting disks are connected to the corresponding starting circuit or ending circuit. The conductive silver sheet also includes a plurality of longitudinal ribs and a plurality of transverse ribs. The longitudinal ribs are arranged along the spacing between the two connecting disks along their length direction, and each longitudinal rib is connected to a corresponding connecting disk at both ends along its length direction. The plurality of longitudinal ribs are spaced apart sequentially along their width direction. The transverse ribs are connected to the plurality of longitudinal ribs sequentially along their length direction, and the plurality of transverse ribs are spaced apart sequentially along the length direction of the longitudinal ribs. The longitudinal ribs and the plurality of transverse ribs enclose and form a plurality of mesh holes.

[0013] By adopting the above technical solution, the two spaced connecting plates are connected to the corresponding starting circuit and ending circuit respectively, which provides a connection interface for electrical connection at the cross-connection point.

[0014] Several longitudinal ribs located between two connecting discs extend along the spacing direction of the connecting discs, bearing the current path between the starting circuit and the ending circuit; several transverse ribs are connected to several longitudinal ribs in sequence along their own length direction, connecting adjacent longitudinal ribs in parallel laterally; the longitudinal and transverse ribs enclose and form a grid hole, so that the entire conductive silver sheet forms a grid-like conductive structure. Thus, when the FPC bends, the bending strain borne by the conductive silver sheet is distributed to each independent longitudinal and transverse rib, and each longitudinal and transverse rib only needs to bear a small local strain, which can reduce the risk of the conductive silver sheet cracking as a whole.

[0015] Meanwhile, the grid-like conductive structure formed by the interweaving of longitudinal and transverse ribs ensures that even if some ribs break due to fatigue, the remaining ribs can still maintain the current path, thus providing conductivity redundancy for the entire conductive silver sheet.

[0016] Optionally, the cross-sectional area of ​​the longitudinal stiffener is larger than the cross-sectional area of ​​the transverse stiffener.

[0017] By adopting the above technical solution, the longitudinal ribs, as the main conductive channel between the two connecting discs, have a larger cross-sectional area, which increases the cross-sectional area of ​​the main current path from the starting circuit to the ending circuit, and correspondingly reduces the resistance. Meanwhile, the transverse ribs, as the auxiliary reinforcement and redundant connection structure between adjacent longitudinal ribs, have a smaller cross-sectional area, which reduces the transverse continuous stiffness and further reduces the bending stiffness of the conductive silver sheet when bent along the longitudinal rib direction. Thus, while ensuring low resistance conduction of the main current path, the bending compliance of the conductive silver sheet is further improved.

[0018] Optionally, both the starting circuit and the ending circuit are provided with a plurality of comb grooves; the connecting plate is provided with a plurality of comb strips; the comb strips are provided in a one-to-one correspondence with the comb grooves and are engaged in a locking fit.

[0019] By adopting the above technical solution, the comb teeth on the connecting plate correspond one-to-one with the comb teeth grooves on the starting circuit or the ending circuit and engage with each other. This changes the peeling path of the overlapping interface between the starting circuit and the ending circuit and the corresponding connecting plate from a straight line to a winding path, thereby improving the peeling resistance of the overlapping interface.

[0020] Meanwhile, the alternating engagement of the comb teeth and comb grooves forms a mechanical interlock within the overlapping interface. Even if the silver-copper adhesion of some overlapping interfaces is lost due to long-term use and aging, the mechanical engagement can still prevent the entire connecting disc from slipping off from the corresponding starting or ending circuit. Furthermore, the multi-point contact between the comb teeth and comb grooves increases the conductive cross-sectional area, reduces the contact resistance of the overlapping interface, and further improves the conductivity reliability of the conductive silver sheet under dynamic bending conditions.

[0021] Optionally, an insulating protective layer is also provided, the insulating protective layer comprising a plurality of protective films corresponding one-to-one with the conductive silver sheets, the protective films being disposed on the side of the corresponding conductive silver sheet away from the cross-line isolation sheet.

[0022] By adopting the above technical solution, the protective film covers the side of the conductive silver sheet away from the jumper isolation sheet, which provides mechanical protection, moisture protection, oxidation protection, and chemical corrosion protection for the conductive silver sheet and the jumper isolation sheet located below the conductive silver sheet. This prevents the conductive silver sheet from experiencing a decline in conductivity due to external scratches, moisture erosion, or oxidation during long-term use, thereby improving the environmental tolerance and service life of the entire jumper structure.

[0023] Optionally, the protective film has a plurality of grooves on its outer surface opposite to the conductive silver sheet, and the grooves are arranged at intervals along the length of the conductive silver sheet; the cross-line isolation sheet has a plurality of fine grooves on its side facing the conductive silver sheet, and the fine grooves are arranged at intervals along the length of the conductive silver sheet; the length directions of both the grooves and the fine grooves are along the width direction of the conductive silver sheet, the grooves penetrate the protective film along their own length direction, and the fine grooves penetrate the cross-line isolation sheet along their own length direction.

[0024] By adopting the above technical solution, several grooves on the protective film extend along the width direction of the conductive silver sheet and penetrate the protective film, reducing the bending resistance of the protective film parallel to the longitudinal ribs. This guides the protective film to bend preferentially along the length direction of the longitudinal ribs, thus avoiding the most unfavorable overall tensile stress condition caused by the simultaneous lateral stretching of several longitudinal ribs perpendicular to their own length. Simultaneously, several fine grooves on the jumper isolation plate extend along the width direction of the conductive silver sheet and penetrate the jumper isolation plate, giving the jumper isolation plate reduced bending stiffness at corresponding positions. This allows it to bend synchronously with the upper protective film, thereby creating equally spaced bending weakening zones along the length direction of the conductive silver sheet in the entire laminated structure, improving the overall bending coordination of the jumper structure.

[0025] Optionally, the grooves and the fine grooves are arranged in a one-to-one correspondence, and the fine grooves and the corresponding grooves are arranged facing each other along the thickness direction of the conductive silver sheet; all the mesh holes arranged sequentially at intervals along the width direction of the conductive silver sheet form a weakening hole group, and several weakening hole groups are arranged sequentially at intervals along the length direction of the conductive silver sheet; the weakening hole groups and the fine grooves are arranged in a one-to-one correspondence, and the grooves, the corresponding weakening hole groups, and the corresponding fine grooves are arranged sequentially along the thickness direction of the conductive silver sheet.

[0026] By adopting the above technical solution, the grooves, weakening hole groups, and fine grooves are arranged in sequence facing each other along the thickness direction of the conductive silver sheet, so that the bending weakening areas on the three-layer structure of the protective film, conductive silver sheet, and cross-line isolation sheet precisely overlap on the same vertical section, forming a three-layer aligned bending hinge band from top to bottom; when the FPC undergoes bending deformation, the three layers of the protective film, conductive silver sheet, and cross-line isolation sheet undergo synchronous and co-positioned concentrated deformation at the hinge band position, avoiding interlayer differential displacement caused by misalignment of bending weakening points in each layer, thereby reducing the interlayer shear driving force caused by inconsistent bending points in each layer.

[0027] Optionally, an insulating anchor is provided in one of the grid holes, with one end of the insulating anchor connected to the cross-line isolation plate and the other end connected to the protective film.

[0028] By adopting the above technical solution, the insulating anchor rigidly connects the protective film and the cross-line isolation plate into one unit in the thickness direction, forming normal tensile resistance and improving the critical stress for interlayer delamination.

[0029] Secondly, the manufacturing method of the vehicle-mounted FPC matrix jumper structure provided in this application adopts the following technical solution: A method for manufacturing an automotive FPC matrix jumper structure includes the following steps: Conductive circuit layer preparation: A conductive network is prepared on the flexible substrate, and the overlapping areas of different lines in the conductive network in spatial projection are defined as bridging points; at the bridging points, corresponding lines of the conductive network are disconnected to form the spaced-apart starting circuit and the ending circuit; Insulating dielectric layer printing: At the bridging points, the bridging isolation sheet is printed and cured; Conductive silver paste layer printing: At the bridging points, a conductive silver sheet is printed on the corresponding bridging isolation sheet and cured, and both ends of the conductive silver sheet are respectively connected to the corresponding starting circuit and the ending circuit.

[0030] By adopting the above technical solution, the starting and ending circuits at the bridging point are formed by disconnecting the corresponding lines of the conductive network. This facilitates the direct formation of bridging isolation sheets and conductive silver sheets through printing processes to achieve bridging connections. This eliminates the need for the lamination process of double-layer FPCs and the SMT patch cord process, simplifying the manufacturing process and reducing material and manufacturing costs. Furthermore, since both the bridging isolation sheets and conductive silver sheets are formed on the same flexible substrate through printing processes, they do not introduce the thickness and rigidity of the physical patch cord device body. This allows the entire FPC to maintain a thin film shape at the bridging position, facilitating subsequent winding and dynamic bending of the FPC.

[0031] Thirdly, the continuity testing method for an on-board FPC matrix jumper structure provided in this application adopts the following technical solution: A continuity test method for an automotive FPC matrix jumper structure, used in the aforementioned automotive FPC matrix jumper structure, includes the following steps: Network addressing and positioning: Import the circuit diagram composed of the conductive line layer and the conductive silver paste layer into the control terminal. Determine the test circuit where the conductive silver sheet under test is located according to the circuit diagram, and extract all exposed nodes on the corresponding test circuit. Calculate the standard resistance range of the test circuit under normal conduction conditions of the conductive silver sheet under test based on the circuit parameters. Non-destructive contact point selection: Select two exposed nodes as test contact points, and the conductive silver sheet under test is located between the two selected test contact points along the electrical signal transmission direction within the corresponding test circuit. Resistance acquisition: Contact the test probe of the measuring device with the two selected test contact points respectively, and acquire the actual resistance value of the test circuit. Continuity determination: If the actual resistance value is within the standard resistance range, the conductive silver sheet is determined to be normally conductive; if the actual resistance value exceeds the standard resistance range, the conductive silver sheet is determined to be abnormally conductive.

[0032] By adopting the above technical solution, during such testing, the test probe only contacts the exposed nodes and does not directly contact the fragile conductive silver sheet, thus avoiding the probe scratching the conductive silver sheet and causing irreversible physical damage to the FPC.

[0033] In summary, this application includes at least one of the following beneficial technical effects: 1. This application employs a flexible substrate, a conductive circuit layer, an insulating dielectric layer, and a conductive silver paste layer stacked sequentially. A crossover isolator provides electrical isolation between the conductive network at the crossover points. Conductive silver sheets connect the spaced-apart starting and ending circuits. These conductive silver sheets, formed through screen printing, replace the physical jumper devices used in existing technologies. Due to the superior flexibility of the conductive silver sheets, stress concentration and tearing during FPC winding or dynamic bending are reduced. Simultaneously, the matrix-arranged grid holes on the conductive silver sheets discretize the originally continuous, large-area conductive silver paste coating into multiple short-span silver paste ribs. This not only reduces the overall silver paste coverage area and continuous stiffness of the conductive silver sheets, improving their bending compliance, but also weakens the local bending strain borne by each silver paste rib when the flexible substrate undergoes dynamic bending or winding. This design reduces the risk of overall brittleness or peeling of the conductive silver sheets due to excessive stiffness, thereby improving the deformation compliance and long-term operational reliability of the FPC under small curvature winding and dynamic bending conditions.

[0034] 2. The structural design of the conductive silver sheet in this application uses a grid-like conductive skeleton formed by longitudinal and transverse ribs. Combined with the differentiated design where the cross-sectional area of ​​the longitudinal ribs is larger than that of the transverse ribs, the longitudinal ribs serve as the main conductive channels, bearing the main current path and bending independently along their own length. The transverse ribs serve as auxiliary reinforcement and redundant connection structures, providing transverse parallel paths. Furthermore, the mechanical interlocking structure formed by the comb teeth on the connecting plate engaging with the comb teeth grooves on the starting and ending circuits makes the overlapping interface less prone to peeling off under dynamic bending conditions. This ensures low resistance conduction at the cross-connection point while improving the peel resistance of the overlapping interface.

[0035] 3. This application utilizes the combined design of the grooves on the protective film, the weakening holes on the conductive silver sheet, and the fine grooves on the cross-line separator to form equally spaced bending hinge bands along the length of the conductive silver sheet in the entire laminated structure. This forces the bending deformation of the FPC to be concentrated on the bending hinge bands during dynamic bending, preventing significant relative sliding displacement between layers. This reduces the interlayer shear peeling driving force caused by inconsistent bending force centers of each layer, thereby improving the long-term operational reliability of the FPC. Attached Figure Description

[0036] Figure 1This is a circuit diagram of the conductive circuit layer and conductive silver paste layer on the flexible substrate of Embodiment 1 of this application.

[0037] Figure 2 This is a schematic diagram of the overall structure of a single jumper structure in Embodiment 1 of this application.

[0038] Figure 3 This is a schematic diagram of the overall structure of the conductive silver sheet in Embodiment 1 of this application.

[0039] Figure 4 This is a schematic diagram of the overall structure of the conductive silver sheet in Embodiment 2 of this application.

[0040] Figure 5 This is a schematic diagram of the overall structure of the bridging circuit in Embodiment 2 of this application.

[0041] Figure 6 This is a cross-sectional structural diagram of the cross-line isolation sheet, conductive silver sheet, and protective film of Embodiment 3 of this application.

[0042] Figure 7 This is a schematic diagram of the overall structure of the conductive silver sheet in Embodiment 3 of this application.

[0043] Figure 8 This is a schematic diagram of the overall structure of the conductive silver sheet in Embodiment 4 of this application.

[0044] Figure 9 This is a cross-sectional structural diagram of the cross-line isolation sheet, conductive silver sheet, and protective film of Embodiment 4 of this application.

[0045] Figure 10 This is a cross-sectional structural diagram of the cross-line isolation sheet, conductive silver sheet, elastic stress relief layer and protective film of Embodiment 5 of this application.

[0046] In the diagram, 1. Flexible substrate; 2. Conductive circuit layer; 21. Conductive network; 211. External contact point; 212. Longitudinal main line; 213. Longitudinal auxiliary line; 214. Transverse line; 22. Bridging circuit; 221. Starting circuit; 222. Ending circuit; 223. Comb groove; 3. Insulating dielectric layer; 31. Bridging strip; 32. Fine groove; 4. Conductive silver paste layer; 41. Conductive silver sheet; 411. Mesh hole; 412. Connecting disc; 4121. Comb bar; 413. Longitudinal rib; 414. Transverse rib; 42. Weakening hole group; 421. Hinge hole group; 422. Anchoring hole group; 43. Insulating anchor; 5. Insulating protective layer; 51. Protective film; 52. Wire groove; 6. Elastic stress relief layer. Detailed Implementation

[0047] The following is in conjunction with the appendix Figure 1 -Appendix Figure 10 This application will be described in further detail below.

[0048] Example 1: A vehicle-mounted FPC matrix jumper structure, referring to... Figure 1 and Figure 2 The system comprises a flexible substrate 1, a conductive circuit layer 2, an insulating dielectric layer 3, a conductive silver paste layer 4, and an insulating protective layer 5. The conductive circuit layer 2 is disposed on the flexible substrate 1. The conductive circuit layer 2 includes a conductive network 21 and several bridging circuits 22. Each bridging circuit 22 includes a starting circuit 221 and an ending circuit 222, which are spaced apart and distributed within the conductive network 21. Both the starting circuit 221 and the ending circuit 222 are electrically connected to the conductive network 21. The conductive silver paste layer 4 includes several conductive silver sheets 41, each corresponding to a bridging circuit 22. One end of each conductive silver sheet 41 is connected to the corresponding starting circuit 221 along its length, and the other end is connected to the corresponding ending circuit 222. The insulating dielectric layer 3 is located between the conductive silver sheets 41 and the conductive network 21, and the insulating protective layer 5 covers the conductive silver sheets 41.

[0049] With this design, the combination of several bridging circuits 22, several conductive silver sheets 41 and conductive network 21 in the conductive circuit layer 2 forms a circuit network covering the entire flexible substrate 1, which enables the FPC to establish a crisscrossing grid-like circuit network using only a single layer of flexible substrate 1.

[0050] Reference Figure 1 and Figure 2 In the flexible substrate 1, the flexible substrate 1 is integrally molded using a PI substrate or a PET substrate. The flexible substrate 1 is in the form of a thin film and has good flexibility, temperature resistance, and dimensional stability. Based on the design of the flexible substrate 1, the entire FPC can withstand bending and winding conditions in the end product. At the same time, the thin and light characteristics of the flexible substrate 1 also meet the development trend of lightweight FPC. In this embodiment, LED beads and other electronic components can also be mounted on the flexible substrate 1 using SMT technology, so that the electronic components are electrically connected to the conductive network 21.

[0051] Reference Figure 1 and Figure 2 In the conductive circuit layer 2, the conductive circuit layer 2 is formed by selective etching of the copper-clad layer on the flexible substrate 1.

[0052] Among them, reference Figure 1The conductive network 21 includes several external contact points 211, several longitudinal main lines 212, several longitudinal auxiliary lines 213, and several transverse lines 214. The external contact points 211 are disposed on the edge of the flexible substrate 1. Each longitudinal main line 212 corresponds to one of the external contact points 211, and one end of each longitudinal main line 212 is connected to its corresponding external contact point 211. The longitudinal auxiliary lines 213 are arranged parallel to and spaced apart from the longitudinal main lines 212. The transverse lines 214 are located between the longitudinal main lines 212 and the longitudinal auxiliary lines 213, with one end connected to the longitudinal main line 212 and the other end connected to the longitudinal auxiliary line 213. Several pads are also disposed on the conductive network 21. These pads serve as electrical connection nodes on the conductive network 21 and are used for mounting and soldering electronic components. The pads on the flexible substrate 1 are connected to the corresponding transverse line 214, the corresponding longitudinal main line 212, or the corresponding longitudinal auxiliary line 213. In another embodiment, the LED beads are mounted on corresponding pads to achieve electrical connection between the LED beads and the conductive network 21.

[0053] Reference Figure 1 and Figure 2 In the circuit topology of the conductive network 21, the area where the horizontal line 214 intersects and overlaps with the vertical main line 212 or the vertical auxiliary line 213 in spatial projection is defined as a bridging point. To avoid short circuits, at a preset bridging point, the corresponding horizontal line 214 is disconnected, forming a starting circuit 221 and an ending circuit 222 that are spaced apart from each other. At this time, the bridging circuit 22 and the corresponding conductive silver sheet 41 are set at the bridging point. The conductive silver sheet 41 is three-dimensional and spans the vertical main line 212 and / or the vertical auxiliary line 213 located below, thereby connecting the disconnected starting circuit 221 and ending circuit 222 to achieve electrical connection.

[0054] Therefore, with the cooperation of several external contact points 211, several longitudinal main lines 212, several longitudinal auxiliary lines 213, several transverse lines 214, several bridging circuits 22 and several conductive silver sheets 41, a circuit network covering the entire flexible substrate 1 is formed.

[0055] Reference Figure 1 and Figure 2 In this embodiment, the bridging circuit 22 includes a starting circuit 221 and an ending circuit 222. Both the starting circuit 221 and the ending circuit 222 are formed by breaking the corresponding horizontal line 214 at the bridging point. The starting circuit 221 and the ending circuit 222 are spaced apart to form a break gap, and the width of the break gap is greater than the width of the vertical main line 212 or vertical auxiliary line 213 that needs to be avoided below it. Based on the setting of the starting circuit 221 and the ending circuit 222, a copper bonding base is provided for the corresponding conductive silver sheet 41, so that the two ends of the conductive silver sheet 41 can be stably bonded to the starting circuit 221 and the ending circuit 222, thereby realizing the electrical connection of the horizontal line 214 at the bridging point.

[0056] Reference Figure 1 and Figure 2 In the insulating dielectric layer 3, the insulating dielectric layer 3 includes a plurality of cross-line insulating sheets 31, which are arranged one-to-one with conductive silver sheets 41. The cross-line insulating sheets 31 are located between the conductive silver sheets 41 and the conductive circuit layer 2, and cover the corresponding plurality of longitudinal main lines 212 and / or plurality of longitudinal auxiliary lines 213. Specifically, the cross-line insulating sheets 31 are formed in one step by screen printing using insulating ink.

[0057] With this design, the cross-line isolation piece 31 forms a reliable electrical isolation between the conductive silver sheet 41 and the longitudinal main line 212 or longitudinal auxiliary line 213 located below it, thereby avoiding short circuits at the cross-connection point.

[0058] Reference Figure 2 and Figure 3 In the conductive silver paste layer 4, a plurality of grid holes 411 are formed on a plurality of conductive silver sheets 41, and the plurality of grid holes 411 are arranged in a matrix.

[0059] With this design, the conductive silver sheet 41 forms a grid-like structure. On the one hand, the opening of several grid holes 411 discretizes the originally continuous large-area silver paste coating into multiple short-span silver paste ribs, reducing the bending strain borne by each silver paste rib. On the other hand, the opening of several grid holes 411 reduces the silver paste coverage area and continuous stiffness of the conductive silver sheet 41, thereby improving the overall bending compliance of the conductive silver sheet 41. This can improve the service life of the FPC under bending conditions.

[0060] Reference Figure 3 In this embodiment, the conductive silver sheet 41 includes two spaced-apart connecting disks 412. A plurality of longitudinal ribs 413 and a plurality of transverse ribs 414 are disposed between the two connecting disks 412. The longitudinal ribs 413 are located between the two connecting disks 412 along their own length direction, and both ends of each longitudinal rib 413 are connected to a corresponding connecting disk 412 along their own length direction. The longitudinal ribs 413 are arranged at intervals along their own width direction. The transverse ribs 414 are arranged along the width direction of the longitudinal ribs 413 along their own length direction, and are fixedly connected to the plurality of longitudinal ribs 413 along their own length direction. The transverse ribs 414 are arranged parallel to each other at intervals along the length direction of the longitudinal ribs 413.

[0061] Reference Figure 2 and Figure 3 When using the conductive silver sheet 41, the two connecting disks 412 are set one-to-one with the corresponding starting circuit 221 and ending circuit 222, and the connecting disks 412 are connected to the corresponding starting circuit 221 or ending circuit 222.

[0062] In this design, the two connecting disks 412 provide large-area, low-resistance copper-silver bonding interfaces for the corresponding starting circuit 221 and ending circuit 222, thereby ensuring the reliability of conduction at the cross-connection point. Several longitudinal ribs 413 and several transverse ribs 414 are interwoven to form a grid-like conductive skeleton, and adjacent longitudinal ribs 413 and transverse ribs 414 are surrounded to form grid holes 411, which makes the structure of the entire conductive silver sheet 41 a grid-like conductive skeleton.

[0063] Reference Figure 3 In this embodiment, the cross-sectional area of ​​the longitudinal ribs 413 of the conductive silver sheet 41 is greater than the cross-sectional area of ​​the transverse ribs 414.

[0064] In this design, since the longitudinal ribs 413 serve as the main conductive channels between the connecting discs 412, their large cross-sectional area ensures sufficient conductive cross-section, thereby increasing the cross-sectional area of ​​the main current path from the starting circuit 221 to the ending circuit 222 and correspondingly reducing the resistance. Meanwhile, the transverse ribs 414, serving as auxiliary reinforcement and redundant connection structures between adjacent longitudinal ribs 413, have a smaller cross-sectional area, reducing lateral continuous stiffness. This further reduces the bending stiffness of the conductive silver sheet 41 when bent along the longitudinal ribs 413, improving the bending compliance of the conductive silver sheet 41.

[0065] Reference Figure 3 In this embodiment, the conductive silver sheet 41 is disposed on the side of the corresponding cross-line isolation sheet 31 away from the flexible substrate 1 by screen printing process. The conductive silver sheet 41 crosses the cross-line isolation sheet 31 along its own length direction, and one end of the conductive silver sheet 41 is connected to the corresponding starting circuit 221 along its own length direction, and the other end is connected to the corresponding ending circuit 222.

[0066] Reference Figure 1 and Figure 2 In the insulating protective layer 5, the insulating protective layer 5 includes a plurality of protective films 51, each of which is correspondingly disposed to a conductive silver sheet 41, and the protective film 51 covers the side of the corresponding conductive silver sheet 41 that is away from the flexible substrate 1.

[0067] With this design, the protective film 51 provides mechanical protection, moisture protection, oxidation protection, and chemical corrosion protection for the conductive silver sheet 41 and the cross-line isolation sheet 31 located below the conductive silver sheet 41. This can prevent the conductive silver sheet 41 from experiencing a decline in conductivity due to external scratches, moisture erosion, or oxidation during long-term use.

[0068] The implementation principle of this application embodiment is as follows: When powered on, an external drive signal is input through several external contact points 211, and then transmitted to each pad in the conductive network 21 along the directions of the longitudinal main line 212, the transverse line 214, and the longitudinal auxiliary line 213. During this process, when the current flows through the bridging point of the transverse line 214, the current flows sequentially through the corresponding starting circuit 221, the conductive silver sheet 41, and the ending circuit 222, thereby allowing the current to cross the bridging point and completing the electrical connection of the transverse line 214 at the bridging point.

[0069] When the FPC is bent, the flexible substrate 1 is wound or bent. At this time, the bending strain acting on the bridging point is first transferred to the conductive silver sheet 41 through the protective film 51. The bending strain is then evenly distributed to several independent longitudinal ribs 413 and transverse ribs 414, and several mesh holes 411 provide local deformation buffer space, so that the conductive silver sheet 41 is not easy to crack as a whole deforms with the flexible substrate 1. Even if individual longitudinal ribs 413 or transverse ribs 414 crack due to long-term fatigue, the remaining longitudinal ribs 413 or transverse ribs 414 can still maintain the current path, thereby ensuring the conductivity stability and service life of the FPC under dynamic bending conditions.

[0070] This embodiment also discloses a method for manufacturing an on-board FPC matrix jumper structure, which specifically includes the following steps: S1. Preparation of conductive line layer 2: A conductive network 21 is prepared on a flexible substrate 1, and the overlapping area of ​​different lines in the conductive network 21 in the spatial projection is defined as a crossover point; at the crossover point, the corresponding transverse line 214 is broken to form a starting circuit 221 and an ending circuit 222 set at intervals.

[0071] Specifically, in step S1, a single-layer PI (polyimide) or PET with a thickness of 12.5 μm to 25 μm is used as the flexible substrate 1. A photosensitive dry film is coated on the copper-clad layer on its surface. Through exposure, development, selective etching, and film removal processes, a high-density conductive network 21 is integrally fabricated on the flexible substrate 1 in one step. At the same time, at the preset line crossing points, the corresponding copper foil lines are etched and broken to form mutually spaced and exposed start circuits 221 and end circuits 222.

[0072] S2, Insulating dielectric layer 3 printing: At the cross-connection point, the cross-line isolation sheet 31 is printed and cured.

[0073] Specifically, in step S2, at the crossover points on the conductive network 21 from step S1, flexible insulating solder resist ink is printed onto the longitudinal main line 212 and / or longitudinal auxiliary line that needs to be avoided using a screen printing process. After printing, the flexible insulating ink is completely cross-linked and cured by ultraviolet light irradiation (UV curing) or baking in a 150°C oven to form a crossover isolation sheet 31 with a thickness of 15μm to 20μm.

[0074] S3, Printing of conductive silver paste layer 4: At the bridging point, a conductive silver sheet 41 is printed and cured on the corresponding bridging isolation sheet 31, and the two ends of the conductive silver sheet 41 are connected to the corresponding starting circuit 221 and ending circuit 222 respectively.

[0075] Specifically, in step S3, based on the insulating dielectric layer 3 prepared in step S2, a highly flexible polymer conductive silver paste is selected, and a fine screen printing plate of 250 to 350 mesh is used. The screen printing plate is pre-designed with a resist matrix pattern corresponding to the grid holes 411, so that the silver paste naturally leaves gaps to form grid holes 411 during printing and deposition, eliminating the need for secondary punching. The above-mentioned screen printing plate is used on the corresponding cross-line isolation sheet 31 to perform screen printing, thereby forming a grid-like conductive silver sheet 41 on the corresponding cross-line isolation sheet 31, and making the two ends of the conductive silver sheet 41 cover and overlap the exposed starting circuit 221 and ending circuit 222 respectively. Then it is placed in an oven at 130°C to 150°C and baked for 30 to 45 minutes to allow the conductive silver sheet 41 to be completely cross-linked and cured.

[0076] S4, Insulation protective layer 5 bonding: A protective film 51 is bonded to the conductive silver sheet 41.

[0077] Specifically, in step S4, the black protective film 51 is attached to the corresponding conductive silver sheet 41 and then sent to a vacuum laminator for hot pressing at a preset lamination temperature (e.g., 150°C to 160°C) and pressure (e.g., 2 to 3 MPa) to ensure that the protective film 51 is tightly attached to the surface of the conductive silver sheet 41.

[0078] In another embodiment, after steps S1 to S4 are completed, electronic components can be further mounted on the flexible substrate 1. Taking the mounting of LED beads as an example: using SMT surface mount technology, low-temperature lead-free solder paste is printed on the corresponding pad areas of the flexible substrate 1 using a stencil; then, an automatic pick-and-place machine is used to mount several LED beads onto the corresponding pads; finally, a reflow soldering process is used to melt the solder paste and complete a reliable electrical connection between the LED beads and the corresponding pads on the flexible substrate 1.

[0079] The implementation principle of this application embodiment is as follows: This application constructs a three-dimensional conductive silver sheet 41 on a single-layer FPC plane using the above-described laminated manufacturing method. Compared with the existing SMT physical jumper or double-layer FPC laminated via process, this process not only avoids the risk of local stress concentration and bending fracture caused by the height and rigidity of physical devices, but also transforms the jumper structure into a flexible conductive silver sheet 41, thereby improving the deformation compliance of the FPC under winding and dynamic bending conditions, and thus improving the long-term operational reliability of the FPC.

[0080] This embodiment also discloses a continuity test method for an on-board FPC matrix jumper structure, which specifically includes the following steps: S100. Test network addressing and positioning: Import the circuit diagram composed of conductive line layer 2 and conductive silver paste layer 4 into the control terminal, determine the test circuit where the conductive silver sheet 41 to be tested is located according to the circuit diagram, extract all exposed nodes on the corresponding test circuit, and calculate the standard resistance range of the test circuit under the normal conduction state of the conductive silver sheet 41 to be tested according to the line parameters of the test circuit.

[0081] Specifically, in step S100, the Gerber file and netlist of the FPC are imported into the ATE (Automatic Test Equipment). The control terminal parses the exact position of the conductive silver sheet 41 under test in the matrix topology and calculates the standard resistance range of the test circuit. The standard resistance range is the theoretical range of the resistance value of the corresponding test circuit when the conductive silver sheet 41 is conducting. Subsequently, all exposed nodes on the test circuit are extracted; the exposed nodes are selected from the exposed metal conductors or exposed pads on the flexible substrate 1 on the corresponding test circuit.

[0082] The specific calculation method for the standard resistance range between two exposed nodes selected as test contact points on the test circuit is as follows: Extract the length, line width, and thickness parameters of the corresponding copper foil lines between the two nodes, and calculate the theoretical resistance of the copper foil lines based on the resistivity of copper; extract the design length and curing thickness of the conductive silver sheet 41 to be tested, and calculate the effective conductive cross-sectional area of ​​the longitudinal main conductive channel of the conductive silver sheet 41 based on the hollow area caused by the arrangement of the mesh holes 411; then calculate the theoretical resistance of the conductive silver sheet 41 based on the volume resistivity of the conductive silver sheet 41; add the theoretical resistance of the copper foil lines, the theoretical resistance of the conductive silver sheet 41, and the preset contact resistance of the silver-copper interface to obtain the theoretical total resistance of the measurement circuit; finally, combine the FPC process tolerance (such as the copper foil etching tolerance and the conductive silver sheet 41 printing thickness tolerance) or the preset tolerance percentage to expand the theoretical total resistance to obtain the standard resistance range of the test circuit.

[0083] S200, Non-destructive contact point selection: Select two exposed nodes as test contact points, and the conductive silver sheet under test 41 is located between the two selected test contact points along the direction of electrical signal transmission in the corresponding test circuit.

[0084] Specifically, in step S200, to avoid the probe directly penetrating the fragile conductive silver sheet 41 area, the system algorithm selects the pair of exposed nodes closest to the conductive silver sheet 41 under test from the extracted exposed nodes as test contact points. These two test contact points must satisfy the following electrical topology requirement: when the electrical signal flows from the first test contact point to the second test contact point, it must necessarily flow through the conductive silver sheet 41 under test.

[0085] S300, Resistance Acquisition: The test probe of the measuring device is brought into contact with the two selected test contact points respectively to acquire the actual resistance value of the test circuit.

[0086] Specifically, in step S300, the test fixture is driven, and test probes using a four-wire Kelvin connection are respectively connected to the two selected test contact points. A constant DC current is injected into the test circuit, and the minute voltage drop between the two test contact points is collected in real time by a measuring device to calculate the current actual resistance value of the test circuit.

[0087] S400, Conductivity Judgment: If the actual resistance value is within the standard resistance range, the conductive silver sheet 41 is considered to be conducting normally; if the actual resistance value exceeds the standard resistance range, the conductive silver sheet 41 is considered to be conducting abnormally.

[0088] Specifically, in step S400, the actual resistance value collected in step S300 is logically compared with the standard resistance range calculated in step S100. If the resistance value falls within the tolerance range (e.g., theoretical value ±15%), the jumper is deemed normal; if the actual resistance value is significantly larger (exceeding the upper tolerance limit), the conductive silver sheet 41 may have hidden defects such as thin printing, incomplete curing, micro-cracks in the internal mesh, or poor silver-copper bonding; if the resistance value is infinite, the jumper is deemed completely broken and failed. The system will automatically record the abnormal coordinates and generate a defective product analysis report.

[0089] The implementation principle of this application embodiment is as follows: This application uses naturally existing exposed nodes as remote proxy test points, and transfers the physical contact position to the bottom copper foil through topology calculation. This can avoid direct contact with the conductive silver sheet 41, thereby preventing mechanical damage to the conductive silver sheet 41.

[0090] Example 2: A vehicle-mounted FPC matrix jumper structure, referring to... Figure 4 and Figure 5The difference between this embodiment and embodiment 1 is that: in the conductive silver sheet 41, the connecting disk 412 is provided with a plurality of comb teeth 4121 on the side facing the corresponding starting circuit 221 or the corresponding ending circuit 222, and the plurality of comb teeth 4121 are arranged in parallel at intervals.

[0091] Both the starting circuit 221 and the ending circuit 222 have a plurality of comb grooves 223 on the side away from the flexible substrate 1. The length direction of the comb grooves 223 is arranged along the length direction of the corresponding starting circuit 221 or the corresponding ending circuit 222, and the plurality of comb grooves 223 are arranged at intervals along their own width direction.

[0092] When the connecting plate 412 is connected to the corresponding starting circuit 221 or ending circuit 222, the comb bar 4121 and the comb groove 223 are set in a one-to-one correspondence, and the comb bar 4121 and the corresponding comb groove 223 are engaged.

[0093] With this design, the alternating engagement of the comb teeth 4121 and comb grooves 223 changes the peeling path of the interface between the starting circuit 221 and the ending circuit 222 and the conductive silver sheet 41 from a straight line to a winding path, thereby improving the peel strength of the interface. At the same time, the alternating engagement of the comb teeth 4121 and comb grooves 223 forms a mechanical interlock within the interface. Even if the silver-copper adhesion of some interfaces is lost due to long-term use and aging, the mechanical engagement can still prevent the connecting disc 412 from slipping off the corresponding starting circuit 221 or ending circuit 222, thus improving the reliability of the interface under dynamic bending conditions.

[0094] In this embodiment, the comb groove 223 is formed by etching the starting circuit 221 and the ending circuit 222 by modifying the etching mask pattern. The comb bar 4121 is formed by designing an opening pattern on the screen printing plate corresponding to the comb groove 223. During silver paste screen printing, the silver paste naturally forms the shape of the comb bar 4121 as it is deposited through the screen printing plate and fills the corresponding comb groove 223, completing the snap-fit ​​engagement.

[0095] The implementation principle of this application embodiment is as follows: When the power is on, when the current passes through the interface between the conductive silver sheet 41 and the corresponding starting circuit 221 or ending circuit 222, the current enters or flows out of the conductive silver sheet 41 through the meshing contact surface of the comb tooth 4121 and the comb tooth groove 223. The multi-point contact between the comb tooth 4121 and the comb tooth groove 223 increases the conductive cross-sectional area and reduces the contact resistance of the interface.

[0096] When the FPC is bent, at the interface between the conductive silver sheet 41 and the corresponding starting circuit 221 or ending circuit 222, the mechanical interlock between the comb bar 4121 and the comb groove 223 prevents the connecting disc 412 from peeling off from the corresponding starting circuit 221 or ending circuit 222 during bending.

[0097] Example 3: A vehicle-mounted FPC matrix jumper structure, referring to... Figure 6 The difference between this embodiment and embodiment 2 is that: a plurality of grooves 52 are formed on the outer surface of the protective film 51 away from the conductive silver sheet 41. The length direction of the grooves 52 is set along the width direction of the conductive silver sheet 41, and the grooves 52 penetrate the protective film 51 along their own length direction. The plurality of grooves 52 are arranged at intervals along the length direction of the conductive silver sheet 41.

[0098] Based on the grooves 52, the bending resistance of the protective film 51 along the direction parallel to the longitudinal ribs 413 is reduced, while the bending stiffness along the direction perpendicular to the longitudinal ribs 413 remains essentially unchanged. When the FPC bends, the grooves 52 guide the protective film 51 to bend preferentially along the length direction of the longitudinal ribs 413. In this bending mode, each longitudinal rib 413 bears bending along its own length direction, and each longitudinal rib 413 can deform independently without interfering with each other. Conversely, if the bending axis is parallel to the direction of the longitudinal ribs 413, all longitudinal ribs 413 will be stretched laterally simultaneously, resulting in the most unfavorable overall tensile stress condition. Therefore, the grooves 52 mechanically reduce the possibility of the most unfavorable bending direction occurring, so that the flexibility gain brought by the grid design of the conductive silver sheet 41 is directed to the most favorable bending direction.

[0099] Reference Figure 6 In this embodiment, the depth of the groove 52 is one-half to one-third of the thickness of the protective film 51, and the cross-section of the groove 52 is V-shaped or U-shaped.

[0100] In this embodiment, the groove 52 is prefabricated on the outer surface of the protective film 51 by a laser scribing machine before the protective film 51 is attached to the conductive silver sheet 41.

[0101] Reference Figure 6 The cross-line isolation plate 31 has several fine grooves 32 on the side facing the conductive silver sheet 41. The length direction of the fine grooves 32 is set along the width direction of the conductive silver sheet 41, and the fine grooves 32 penetrate the width of the cross-line isolation plate 31 along their own length direction. Several fine grooves 32 are arranged at intervals along the length direction of the conductive silver sheet 41.

[0102] Reference Figure 6 In this embodiment, the depth of the groove 32 is one-half to one-third of the thickness of the cross-line separator 31, and the cross-section of the groove 32 is V-shaped or U-shaped.

[0103] In this embodiment, the groove 32 is achieved by setting a semi-through-hole pattern at the corresponding position on the screen printing plate during the screen printing of the cross-line separator 31. The mesh is denser or the opening is smaller at the semi-through-hole position, so that the amount of ink deposited at that position is about half that of the rest of the complete area, thereby forming the groove 32 with a depth difference simultaneously in one printing process. The groove 32 forming process is completed simultaneously with the main body printing of the cross-line separator 31, without the need for additional manufacturing processes.

[0104] Reference Figure 7 On the conductive silver sheet 41, all the grid holes 411 arranged at intervals along the width direction of the conductive silver sheet 41 form a weakening hole group 42, which makes a number of weakening hole groups 42 arranged at intervals along the length direction of the conductive silver sheet 41.

[0105] Reference Figure 6 and Figure 7 The wire groove 52, the corresponding weakening hole group 42 and the corresponding fine groove 32 are arranged one-to-one, and the wire groove 52, the corresponding weakening hole group 42 and the corresponding fine groove 32 are arranged sequentially along the thickness direction of the conductive silver sheet 41. The width of the wire groove 52 and the fine groove 32 is smaller than the span of the mesh hole 411 in the corresponding weakening hole group 42 along the length direction of the conductive silver sheet 41.

[0106] With this design, three aligned bending hinge bands are formed sequentially from top to bottom: the groove 52 on the protective film 51, the weakening hole group 42 on the conductive silver sheet 41, and the fine groove 32 on the cross-line isolation sheet 31. The bending weakening areas of these three layers coincide on the same vertical cross section. Furthermore, since the width of the groove 52 and the fine groove 32 is smaller than the span of the grid holes 411 in the corresponding weakening hole group 42, the two sides of the groove 52 and the fine groove 32 always fall within the opening range of the grid holes 411 in the vertical projection. When the FPC undergoes bending deformation, the three layers of material—the protective film 51, the conductive silver sheet 41, and the cross-line isolation sheet 31—undergo synchronous and co-positional concentrated deformation at the hinge band position, thereby avoiding interlayer differential displacement caused by misalignment of the bending hinge position and reducing the interlayer shear driving force caused by inconsistent bending points of each layer.

[0107] The implementation principle of this application embodiment is as follows: When the FPC bends, the groove 52 on the protective film 51 first guides the bending to occur preferentially along the length direction of the longitudinal rib 413. The bending deformation is then concentrated on the equally spaced hinge bands: within each hinge band, the protective film 51 bends at the groove 52, the mesh holes 411 on the conductive silver sheet 41 provide strain buffer space, and the fine grooves 32 on the cross-line isolation sheet 31 bend synchronously. The three layers of the protective film 51, the conductive silver sheet 41, and the cross-line isolation sheet 31 tend to deform synchronously on the same vertical cross section, and the relative sliding displacement between layers decreases. In the complete area between adjacent hinge bands, the protective film 51, the conductive silver sheet 41, and the cross-line isolation sheet 31 all maintain their complete thickness and original stiffness, and hardly any bending deformation occurs. This can improve the coordination of bending deformation between the layers of the conductive silver sheet 41, thereby improving its fatigue fracture resistance.

[0108] Example 4: A vehicle-mounted FPC matrix jumper structure, referring to... Figure 8 The difference between this embodiment and embodiment 3 is that: the weakened hole groups 42 are divided into hinge hole groups 421 and anchor hole groups 422, and the hinge hole groups 421 and anchor hole groups 422 are arranged alternately along the length direction of the conductive silver sheet 41.

[0109] Among them, reference Figure 8 and Figure 9 The hinge hole group 421 is configured one-to-one with the wire groove 52 and the fine groove 32. The grid holes 411 in the hinge hole group 421 are aligned with the wire groove 52 on the protective film 51 and the fine groove 32 on the cross-line isolation plate 31 in the vertical projection. No filler is placed in the grid holes 411 in the hinge hole group 421, keeping them in a cavity state, which serves as a bending buffer space to accommodate the local deformation displacement of adjacent longitudinal ribs 413 and transverse ribs 414 when the FPC is bent.

[0110] Conversely, refer to Figure 8 and Figure 9 An insulating anchor post 43 is provided in the grid hole 411 within the anchor hole group 422. The insulating anchor post 43 is spaced apart from the inner sidewall of the corresponding grid hole 411. The bottom of the insulating anchor post 43 is integrally connected to the cross-line isolation plate 31, and the top of the insulating anchor post 43 is fixedly connected to the protective film 51.

[0111] Reference Figure 9Specifically, the processing of the insulating anchor post 43 is as follows: On the screen printing plate of the cross-line isolation sheet 31, an insulating anchor post 43 pattern, independent of the main pattern of the cross-line isolation sheet 31, is designed at the corresponding position of the anchor hole group 422. Through thick printing or overprinting processes, the height of the insulating ink accumulation at the insulating anchor post 43 is higher than the thickness of the main body of the cross-line isolation sheet 31. Subsequently, when screen printing the conductive silver sheet 41, a printing plate with a specific adhesive-blocking pattern is used. The size of the adhesive-blocking area (i.e., the non-ink-through area) on the screen corresponding to the position of the insulating anchor post 43 is larger than the cross-sectional size of the insulating anchor post 43. Thus, during the process of squeegeeing the silver paste, the annular area around the insulating anchor post 43 is blocked by the adhesive-blocking area of ​​the screen, and the silver paste cannot be deposited around the side wall of the insulating anchor post 43, thereby forcibly leaving a blank space to form the corresponding grid hole 411, and ensuring that the inner side wall of the grid hole 411 of the formed conductive silver sheet 41 forms a physical gap with the insulating anchor post 43. Finally, when attaching the protective film 51, the protruding part at the top of the insulating anchor 43 is directly adhered to the protective film 51.

[0112] Reference Figure 8 and Figure 9 With this design, two functional zones are arranged alternately along the length of the conductive silver sheet 41: The first type is the hinge zone. Within this functional zone, the grooves 52 on the protective diaphragm 51, the hinge mesh holes 411 in a hollow state, and the fine grooves 32 on the cross-line isolation plate 31 are arranged sequentially and directly opposite each other. With the vertical alignment and superposition of these three structures, all three layers of material in this area are in a weakened bending state, maximizing overall flexibility. Since there are no insulating anchors 43 within the hinge zone, there is no strong constraint on the relative movement of the layers, thus allowing the protective diaphragm 51, the conductive silver sheet 41, and the cross-line isolation plate 31 to undergo concentrated bending deformation at this location.

[0113] The second type is the anchoring zone. Within this functional zone, the protective film 51, the insulating anchor 43, and the cross-line isolation plate 31 are aligned in their vertical projection. All three layers of material in this area maintain their full thickness and high rigidity, with almost no bending deformation. Simultaneously, the insulating anchor 43 rigidly connects the protective film 51 and the cross-line isolation plate 31 in the thickness direction, forming normal tensile resistance, thereby increasing the critical stress for interlayer delamination. Furthermore, the gaps between the insulating anchor 43 and the sidewalls of the longitudinal and transverse reinforcing bars 413 and 414 ensure that the longitudinal and transverse reinforcing bars 413 and 414 can still deform freely during bending, thus not compromising the flexibility of the conductive silver sheet 41.

[0114] Under the above-described partitioned design, the hinge zone and the anchoring zone are arranged alternately along the length of the conductive silver sheet 41, forming a rhythmic and coordinated structure. The hinge zone is responsible for absorbing most of the bending deformation, while the anchoring zone is responsible for locking the layered structure composed of the protective film 51, the conductive silver sheet 41, and the cross-line insulating sheet 31.

[0115] The implementation principle of this application embodiment is as follows: When the FPC is subjected to dynamic bending, the bending deformation is forcibly concentrated on the hinge zones arranged at equal intervals. Within each hinge zone, the three layers—protective film 51, conductive silver sheet 41, and cross-line isolation sheet 31—achieve synchronous bending deformation without misalignment at the same vertical cross-section through the geometric combination of the wire groove 52, the cavity mesh holes 411 within the hinge hole group 421, and the fine groove 32. Within the anchoring zone between the hinge zones, insulating anchors 43 rigidly connect the three layers along the thickness direction. This anchoring zone not only does not bend itself, but the insulating anchors 43 continuously provide normal tensile force to resist bending peeling stress. This improves the stability of the entire jumper structure during FPC bending.

[0116] Example 5: A vehicle-mounted FPC matrix jumper structure, referring to... Figure 10 The difference between this embodiment and Embodiment 4 is that an elastic stress relief layer 6 is provided between the conductive silver sheet 41 and the protective film 51, and the insulating anchor 43 passes through the elastic stress relief layer 6 axially. The elastic stress relief layer 6 is made of silicone-modified polyurethane elastomer or UV-cured soft acrylate elastomer material, and the elastic modulus of the elastic stress relief layer 6 is 0.01 GPa to 0.1 GPa, and the thickness is 5 μm to 15 μm.

[0117] Specifically, refer to Figure 10 The elastic stress relief layer 6 is coated onto the side of the conductive silver sheet 41 facing away from the flexible substrate 1 using a screen printing process. After the conductive silver sheet 41 has cured, the elastic stress relief layer 6 is printed in the form of a liquid paste. Under the combined action of the pressure applied by the printing squeegee and the gravity flow of the liquid paste itself, the elastic paste not only evenly covers the top surface of the longitudinal ribs 413 and the transverse ribs 414, but also flows downward into each grid hole 411 of the conductive silver sheet 41.

[0118] Specifically, in the empty mesh holes 411, the elastomer slurry flows in and partially or completely fills the mesh holes 411. In the mesh holes 411 containing the insulating anchors 43, the elastomer slurry flows downward into the annular gap between the insulating anchors 43 and the inner sidewall of the mesh holes 411, and coats the lower half of the sidewall of the insulating anchors 43. After a thermosetting or UV curing process, the liquid slurry cross-links and cures into a continuous and highly adhesive low-modulus elastomer film. Because the top of the insulating anchor 43 is designed to be higher than the thickness of the elastic stress relief layer 6, the top of the insulating anchor 43 still protrudes from the outer surface of the elastic stress relief layer 6 after curing. Finally, a protective film 51 is attached to the outer surface of the elastic stress relief layer 6 facing away from the conductive silver sheet 41. At this time, the top of the insulating anchor 43 will pass through the elastic stress relief layer 6 and directly bond to the protective film 51.

[0119] In this design, the elastic stress relief layer 6 not only forms a continuous flexible interlayer in the horizontal direction between the protective film 51 and the conductive silver sheet 41, but the portion of it that is solidified and embedded inside the mesh holes 411 also forms a three-dimensional flexible wrapping around the fragile silver paste ribs. First, the elastomers embedded in the mesh holes 411 significantly increase the mechanical contact and adhesion area between the elastic stress relief layer 6 and the conductive silver sheet 41, improving the interlayer bonding force. Second, the elastomers filled in the mesh holes 411 essentially act as micro-flexible buffer pads. When the FPC bends, causing the conductive silver sheet 41 to undergo local relative displacement or micro-deformation, these elastomers embedded in the mesh holes 411 can absorb, buffer, and disperse the compressive shear stress on the sidewalls of the ribs.

[0120] Furthermore, the low elastic modulus of the elastic stress relief layer 6 means that it transmits almost no stress to the outside when interlaminar shear deformation occurs. When the FPC is bent as a whole, the protective film 51 and the conductive silver sheet 41 will inevitably experience asynchronous interlaminar relative displacement due to the difference in distance from the bending neutral surface. This destructive differential displacement is flexibly absorbed and digested by the elastic stress relief layer 6 through its internal large deformation shear slip. This avoids the problem in existing designs where the rigid adhesive layer directly transmits the displacement constraint force of the protective film 51 to the sidewall of the mesh hole 411. As a result, each longitudinal rib 413 and transverse rib 414 of the conductive silver sheet 41 can achieve independent free deformation under the pull of the peeling external force when bending along with the flexible substrate 1. Simultaneously, this also allows the protective film 51 to quickly bend into place when concentrated bending occurs at the groove 52, only needing to overcome the weak shear resistance of the elastic stress relief layer 6, thus fully utilizing the preferential bending guiding effect of the groove 52. Subsequently, due to the decoupling effect of the elastic stress relief layer 6, it will only slowly drive the conductive silver sheet 41 below to deform at a low stress level. This reduces the actual instantaneous bending loading rate borne by the conductive silver sheet 41, thereby helping to extend the bending fatigue life of the conductive silver sheet 41.

[0121] The implementation principle of this embodiment is as follows: When the FPC is subjected to severe bending, the protective diaphragm 51 preferentially undergoes concentrated bending due to the structural weakening effect of the groove 52. However, this rapid bending deformation is first transmitted to the elastic stress relief layer 6 below it. The elastic stress relief layer 6, through its own extremely low modulus shear deformation, decouples and softens the relatively rigid and severe displacement motion of the protective diaphragm 51, and then transmits it to the conductive silver sheet 41 at the bottom. This makes the bending load curve actually received by the conductive silver sheet 41 smoother and the deformation rate significantly reduced. At the same time, some of the elastic bodies embedded in the mesh holes 411 on the elastic stress relief layer 6 are synchronously deformed under pressure, further absorbing the surge of local micro-stress on the sidewalls of the mesh holes 411 on the conductive silver sheet 41. This can further improve the stability of the entire jumper structure during the bending process of the FPC.

[0122] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A vehicle-mounted FPC matrix jumper structure, characterized in that, include: A flexible substrate (1) is provided with a conductive circuit layer (2). The conductive circuit layer (2) includes a conductive network (21) and a plurality of bridging circuits (22). The bridging circuits (22) include a starting circuit (221) and an ending circuit (222). The starting circuit (221) and the ending circuit (222) are spaced apart and distributed in the conductive network (21). The starting circuit (221) and the ending circuit (222) are both electrically connected to the conductive network (21). The conductive silver paste layer (4) includes a plurality of conductive silver sheets (41), each of which is correspondingly arranged with respect to the bridging circuit (22). One end of each conductive silver sheet (41) is connected to the corresponding starting circuit (221), and the other end is connected to the corresponding ending circuit (222). Each conductive silver sheet (41) has a plurality of grid holes (411) arranged in a matrix. Each conductive silver sheet (41) includes two spaced connecting disks (412), each of which is correspondingly arranged with respect to the starting circuit (221) and the ending circuit (222). The connecting disks (412) are connected to the corresponding starting circuit (221) or the ending circuit. (222) Connection; The conductive silver sheet (41) further includes a plurality of longitudinal ribs (413) and a plurality of transverse ribs (414). The longitudinal ribs (413) are arranged along the interval direction of the two connecting discs (412) along their length direction. The two ends of the longitudinal ribs (413) are respectively connected to the corresponding connecting discs (412) along their own length direction. The plurality of longitudinal ribs (413) are arranged at intervals along their own width direction. The transverse ribs (414) are connected to the plurality of longitudinal ribs (413) along their own length direction. The plurality of transverse ribs (414) are arranged at intervals along the length direction of the longitudinal ribs (413). The longitudinal ribs (413) and the plurality of transverse ribs (414) enclose to form a plurality of mesh holes (411). The insulating dielectric layer (3) includes a plurality of cross-line isolation sheets (31), wherein the cross-line isolation sheets (31) are arranged in a one-to-one correspondence with the conductive silver sheets (41), and the cross-line isolation sheets (31) are arranged on the side of the conductive silver sheets (41) facing the flexible substrate (1). An insulating protective layer (5) is also provided, the insulating protective layer (5) includes a plurality of protective films (51) that are disposed one-to-one with the conductive silver sheet (41), the protective films (51) being disposed on the side of the conductive silver sheet (41) facing away from the cross-line isolation sheet (31); The protective film (51) has a plurality of grooves (52) on its outer surface away from the conductive silver sheet (41), and the plurality of grooves (52) are arranged sequentially at intervals along the length direction of the conductive silver sheet (41). The cross-line isolation plate (31) has a plurality of grooves (32) on the side facing the conductive silver sheet (41), and the plurality of grooves (32) are arranged sequentially at intervals along the length direction of the conductive silver sheet (41). The length directions of the groove (52) and the fine groove (32) are both arranged along the width direction of the conductive silver sheet (41). The groove (52) penetrates the protective film (51) along its own length direction, and the fine groove (32) penetrates the cross-line isolation sheet (31) along its own length direction. The groove (52) and the fine groove (32) are arranged in a one-to-one correspondence, and the fine groove (32) and the corresponding groove (52) are arranged facing each other along the thickness direction of the conductive silver sheet (41); All the mesh holes (411) arranged sequentially at intervals along the width direction on the conductive silver sheet (41) form a weakening hole group (42), and several weakening hole groups (42) are arranged sequentially at intervals along the length direction of the conductive silver sheet (41); the weakening hole group (42) is arranged one-to-one with the fine groove (32), and the wire groove (52), the corresponding weakening hole group (42) and the corresponding fine groove (32) are arranged sequentially along the thickness direction of the conductive silver sheet (41).

2. The vehicle-mounted FPC matrix jumper structure according to claim 1, characterized in that, The cross-sectional area of ​​the longitudinal stiffener (413) is greater than the cross-sectional area of ​​the transverse stiffener (414).

3. The vehicle-mounted FPC matrix jumper structure according to claim 1, characterized in that, The starting circuit (221) and the ending circuit (222) are each provided with a plurality of comb grooves (223); the connecting plate (412) is provided with a plurality of comb strips (4121); the comb strips (4121) and the comb grooves (223) are provided in a one-to-one correspondence and are engaged.

4. The vehicle-mounted FPC matrix jumper structure according to claim 1, characterized in that, An insulating anchor (43) is provided in several of the grid holes (411). One end of the insulating anchor (43) is connected to the cross-line isolation plate (31), and the other end is connected to the protective film (51).

5. A method for manufacturing an in-vehicle FPC matrix jumper structure, used to manufacture the in-vehicle FPC matrix jumper structure according to any one of claims 1-4, characterized in that, Includes the following steps: Preparation of conductive line layer (2): The conductive network (21) is prepared on the flexible substrate (1), and the overlapping area of ​​different lines in the conductive network (21) in the spatial projection is defined as the bridging point; at the bridging point, the corresponding lines of the conductive network (21) are disconnected to form the starting circuit (221) and the ending circuit (222) set at intervals. Insulating dielectric layer (3) printing: At the cross-connection, the cross-line isolation sheet (31) is printed and cured; Printing of conductive silver paste layer (4): At the crossover point, the conductive silver sheet (41) is printed and cured on the corresponding crossover isolation sheet (31), and the two ends of the conductive silver sheet (41) are connected to the corresponding starting circuit (221) and the ending circuit (222) respectively.

6. A continuity test method for an on-board FPC matrix jumper structure, used for the on-board FPC matrix jumper structure as described in any one of claims 1-4, characterized in that, Includes the following steps: Test network addressing and positioning: Import the circuit diagram composed of the conductive line layer (2) and the conductive silver paste layer (4) into the control terminal, determine the test circuit where the conductive silver sheet (41) to be tested is located according to the circuit diagram, extract all exposed nodes on the corresponding test circuit, and calculate the standard resistance range of the test circuit under the normal conduction state of the conductive silver sheet (41) to be tested according to the line parameters of the test circuit. Non-destructive contact point selection: Select two exposed nodes as test contact points, and the conductive silver sheet (41) to be tested is located between the two selected test contact points along the electrical signal transmission direction in the corresponding test circuit; Resistance acquisition: The test probe of the measuring device is brought into contact with the two selected test contact points respectively to acquire the actual resistance value of the test circuit; Conductivity determination: If the actual resistance value is within the standard resistance value range, the conductive silver sheet (41) is considered to be conducting normally; if the actual resistance value exceeds the standard resistance value range, the conductive silver sheet (41) is considered to be conducting abnormally.

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