A method for manufacturing a large-size flexible circuit board that replaces a wiring harness

Abstract

The present invention discloses a method for manufacturing a large-size flexible circuit board that replaces a wiring harness type, comprising: manufacturing a covering film core board through a previous process; then manufacturing a punching die, and performing alignment punching of a slot body on the covering film core board, and forming a flexible board connecting bridge in the slot body, so that the entire board forms a punched plate, taking a reinforcing sheet to open a window corresponding to the slot body to form a reinforced slot body, the reinforced slot body is provided with a plurality of reinforcing connecting bridges, and the entire board forms a reinforced plate; the reinforcing connecting bridges and the flexible board connecting bridges are staggered; the reinforcing plate is attached to the punched plate, and then formed into a circuit board; the covering film is attached by means of a panel structure, and punching is performed with a punching mold, thereby solving the problems of easy scattering and difficulty in attaching the covering film attached in batches; the staggered design of the flexible board connecting bridge and the reinforcing plate connecting bridge allows selective processing during final forming, thereby solving the problems of easy material entanglement, difficulty in smooth chip removal, and generation of milling burrs and wiredrawing during milling; the overall processing flow forms effective coordination.

Description

Technical Field

[0001] The present invention relates to the field of printed circuit board manufacturing, in particular to the field of flexible circuit board manufacturing, and more particularly to a method for manufacturing a large-size flexible circuit board that replaces a wiring harness type. Background Art

[0002] With the development of industries such as intelligent connected vehicles and low-altitude aircraft, the circuit boards used are required to distribute more wiring harnesses in the same size of space to achieve more complex and diverse functions. Therefore, the application model of using flexible circuit boards to replace wiring harnesses has emerged.

[0003] For a type of large-size flexible circuit board that replaces wiring harnesses, the ends of the board need to be plugged in or welded with pads. Such pads require a hard reinforcing plate to provide support to realize the processing and application process of plugging and welding.

[0004] Currently, this type of circuit board is usually manufactured using a panel structure, which has two processing defects:

[0005] On the one hand, whether the flexible circuit board is formed first or the covering film is attached in batches and then formed, there will be a process of attaching multiple parallel unit covering films, but the covering film is large in size, and it is easy for the covering film to scatter during forming, resulting in problems such as difficulty in attachment; on the other hand, if the traditional single-piece attachment reinforcement plate method is adopted, there will be problems with positioning accuracy, which is easy to cause problems such as misalignment. In addition, in the subsequent forming process, if punching is used, the reinforcement sheet is easy to rub against the punching knife, causing obstruction to the punching knife, and if milling is used, due to its large size and the fact that the covering film layer and insulating medium layer of the flexible circuit board are generally made of polyimide, which is more flexible, it is easy for the material to be entangled in the milling, making it difficult to remove chips smoothly, resulting in milling burrs, pulling, and wiredrawing.

[0006] Therefore, in order to solve the above-mentioned problems, it is necessary to provide a method for manufacturing an alternative wiring harness type large-size flexible circuit board. Summary of the Invention

[0007] The present invention aims to solve the problems of the existing technology for making large-sized flexible circuit boards that replace wiring harnesses, such as difficulty in attaching cover films and the easy generation of burrs and wiredrawing during milling and forming. A method for making a circuit board with high-precision metallized half-holes on the board edge is proposed. The circuit board is processed using a panel structure formed by splicing flexible copper-clad laminates. The circuit board is designed with a forming line, and the area outside the forming line is an inactive area. The production method includes the following steps:

[0008] S10: forming a circuit pattern on the flexible copper clad laminate, and then forming a covering film layer to form a covering film core board.

[0009] S20: Making a punching die, wherein the top die of the punching die is designed with a first row of punching knives and a second row of punching knives, the first row of punching knives corresponds to the forming line, the second row of punching knives is arranged outside the forming line, and the first row of punching knives and the second row of punching knives are correspondingly provided with openings.

[0010] S30: using the punching die to perform alignment punching on the covering film core board to form a trough body, wherein the opening corresponds to the position of the covering film core board to form a flexible board connecting bridge to form a punched board.

[0011] S40: Take a reinforcing sheet and open a window corresponding to the slot body to form a reinforcing slot body. The reinforcing slot body is composed of a plurality of intermittent through slots. The intermittent positions form reinforcing connecting bridges, and the entire plate forms a reinforcing plate. The reinforcing connecting bridges are staggered with the flexible plate connecting bridges.

[0012] S50: attaching the reinforcing plate to the punched plate and then shaping it to form the circuit board.

[0013] Furthermore, the flexible plate connecting bridges of adjacent punched plates in the panel structure are staggered.

[0014] Furthermore, the edge size of the reinforcement groove body adjacent to the ineffective area is smaller than the edge size formed by the second row of punching cutters.

[0015] Furthermore, a protrusion is provided in the bottom die of the punching die corresponding to the enclosed area of ​​the first row of punching knives.

[0016] Furthermore, the size of one side of the protrusion is smaller than the size of the enclosed pattern of the first row of punching cutters.

[0017] Furthermore, the cross section of the protrusion is a right-angled trapezoid, and the hypotenuse of the trapezoid faces the top mold.

[0018] Furthermore, the forming is: milling the reinforcing plate connecting bridge and laser cutting the flexible plate connecting bridge.

[0019] Furthermore, the distance between the second row of punching knives and the first row of punching knives is 0.1 mm to 3.0 mm.

[0020] Furthermore, the offset distribution distance between the reinforcing connecting bridge and the flexible board connecting bridge is greater than or equal to 50 μm.

[0021] Furthermore, the spacing between adjacent flexible copper-clad laminates in the panel structure is greater than or equal to 1.5 mm.

[0022] The technical solution of the present invention attaches the covering film by means of a panel structure and cooperates with the punching mold for punching, thereby solving the problems of the prior art in which the covering film is easily scattered during batch attachment, resulting in difficulty in attachment; the punching mold is used to punch out the groove body to form a pre-formed circuit board, and further a convex block is designed on the bottom film of the punching mold to play a supporting role at the moment of punching, thereby avoiding unnecessary pulling between the covering film core board and the punching knife, and ensuring the quality and flatness of the cutting edge of the groove body; by first opening a window on the reinforcement plate corresponding to the groove body and then attaching the reinforcement, the friction between the reinforcement plate and the punching knife is reduced, thus solving the problem of the prior art in which the forming and punching are easy to be reinforced. The problems of friction with the punching knife and obstruction to the punching knife are solved, and the structure of the reinforcement plate connecting bridge is designed to form the effect of batch attachment reinforcement, which improves the alignment accuracy of the reinforcement attachment; through the staggered design of the flexible board connecting bridge and the reinforcement plate connecting bridge, the reinforcement plate connecting bridge is further milled during the final molding, and the flexible board connecting bridge is selectively molded by laser ablation molding, which solves the existing molding and milling technology, which easily involves the covering film layer and the insulating medium layer of the flexible circuit board, making it difficult to remove chips smoothly, resulting in milling burrs, pulling, and wiredrawing. The overall processing flow forms an effective coordination before and after to achieve high-precision processing of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0024] Figure 1 Schematic diagram of the process flow of an embodiment of the present invention;

[0025] Figure 2 Schematic diagram of a planar surface of a membrane core plate according to an embodiment of the present invention;

[0026] Figure 3 A schematic diagram of punching design data according to an embodiment of the present invention;

[0027] Figure 4 Schematic diagram of the cross-sectional structure of a punching die according to an embodiment of the present invention;

[0028] Figure 5 for Figure 4 Schematic diagram of the cross-sectional structure of AA;

[0029] Figure 6 Schematic diagram of the planar structure of the punched plate according to the embodiment of the present invention;

[0030] Figure 7Schematic diagram of the planar structure of a reinforcement plate according to an embodiment of the present invention;

[0031] Figure 8 Schematic diagram of the planar structure of a reinforced copper clad laminate according to an embodiment of the present invention;

[0032] Figure 9 Schematic diagram of the planar structure of a circuit board according to an embodiment of the present invention;

[0033] Figure 10 for Figure 9 Schematic diagram of the BB cross-section structure.

[0034] Explanation of the accompanying drawings: 10, covering film core board; 1010, forming line; 1020, covering film layer; 20, punching die; 2010, top die; 2010a, first row of punching knives; 2010b, second row of punching knives; 2010c, positioning hole; 2020, bottom die; 2020a, bump; 2020b, ejector pin; 30, punching board; 3010, trough body; 3020, flexible board connecting bridge; 40, reinforcement board; 4010, reinforcement trough body; 4020, reinforcement board connecting bridge; 50, reinforcement copper clad board; 5010, staggered distribution distance; 60, circuit board.

[0035] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, inside, outside, etc.) are only used to explain the relative position relationship and movement status of the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0038] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0039] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0040] The existing technology usually makes windows in the covering film through the corresponding panel structure, and then attaches them to form a structure with batch-attached covering films. However, due to the large size of the covering film and the presence of multiple covering films attached in parallel, the covering film is prone to scattering during molding, resulting in problems such as difficulty in alignment and attachment, which brings great obstacles to processing; similarly, when the size of the flexible circuit board core board or the flexible board body is large, the punching and cutting shape processing will also have the problem of scattering (not shown in the drawings).

[0041] See also Figure 1 , Figure 1 Schematic diagram of the process flow of an embodiment of the present invention.

[0042] The manufacturing process of the embodiment of the present invention includes using Figure 2 The following will implement the various steps in the process Figure 2 Each step in the process is further explained step by step.

[0043] The circuit board of this embodiment is processed using a panel structure formed by splicing flexible copper-clad laminates. The circuit board is designed with a forming line 1010, and the area outside the forming line 1010 is an invalid area.

[0044] See also Figure 2 , Figure 2 It is a planar schematic diagram of a covering membrane core board according to an embodiment of the present invention.

[0045] S10: A circuit pattern is produced on the flexible copper clad laminate, and then a covering film layer 1020 is produced to form a covering film core board 10, providing a processing basis for subsequent processes.

[0046] In this embodiment, the spacing between adjacent flexible copper clad laminates in the panel structure is greater than or equal to 1.5 mm. By controlling the minimum spacing between adjacent flexible copper clad laminates to 1.5 mm, it not only helps to maintain the stability between adjacent flexible copper clad laminates in the panel structure, as well as the support and connectivity of the flexible copper clad laminates during processing, but also facilitates the punching operation in the subsequent process, avoiding problems such as damage to the flexible copper clad laminates due to punching errors caused by the adjacent flexible copper clad laminates being too close.

[0047] See also Figure 3 、 Figure 4 and Figure 5 , Figure 3 A schematic diagram of punching design data according to an embodiment of the present invention; Figure 4Schematic diagram of the cross-sectional structure of a punching die according to an embodiment of the present invention; Figure 5 for Figure 4 Schematic diagram of the cross-sectional structure of AA.

[0048] S20: Make a punching die 20. The top die 2010 of the punching die 20 is designed with a first row of punching knives 2010a and a second row of punching knives 2010b. The first row of punching knives 2010a corresponds to the forming line 1010, and the second row of punching knives 2010b is arranged outside the forming line 1010. Openings are correspondingly provided in the first row of punching knives 2010a and the second row of punching knives 2010b.

[0049] The punching die 20 of this embodiment is composed of a top die 2010 and a bottom die 2020, wherein the top die 2010 is equipped with two rows of punches: a first row of punches 2010a (corresponding to the forming line 1010) and a second row of punches 2010b (located in the inactive area). The bottom die 2020 is provided with ejector pins 2020b corresponding to the positioning holes 2010c on the top die 2010. After the subsequent process, the circuit board 60 is punched to form the groove 3010, forming a pre-formed circuit board 60. At the same time, the first row of punches The several openings set by 2010a and the second row of punches 2010b, the parts that are not cut off in the corresponding areas of the groove body 3010, are retained as flexible board connection bridges 3020, forming a covering film core board 10 connected to the invalid area through the flexible board connection bridges 3020, and are retained on the panel structure. To a certain extent, the integrity of the entire panel structure is maintained, so that the circuit board 60 after punching can maintain a certain stability, and also provides a convenient processing basis for subsequent processing.

[0050] Furthermore, the spacing between the second row of punching knives 2010b and the first row of punching knives 2010a is 0.1mm to 3.0mm, that is, the width of the groove body 3010 formed by punching is 0.1mm to 3.0mm. On the one hand, it provides sufficient spacing for the forming punching cutting path of the subsequent process to avoid the poor pre-forming effect caused by the groove body 3010 width being too narrow and the overly dense punching, and it is still easy for the covering film material to be caught in the milling, making it difficult to smoothly remove chips, resulting in milling burrs, pulling, wire drawing and other problems; on the other hand, if the distance difference between the first row of punching knives 2010a and the second row of punching knives 2010b is too large, the span of the flexible board connecting bridge 3020 will be too large, which is not conducive to forming the stability of the overall panel structure. Therefore, by controlling the punching knife spacing, it is beneficial to achieve delicate and smooth cutting edges in the forming process, reducing the possibility of burrs and other defects, thereby improving the quality of the circuit board 60; and the double-row punching knife slotting form is used instead of the single-row punching knife seam form to avoid the single-row punching knife pulling the board body when the seam is withdrawn.

[0051] In this embodiment, a protrusion 2020a is provided in the enclosed area corresponding to the first row of punching knives 2010a in the bottom mold 2020 of the punching mold 20, that is, by designing the protrusion 2020a in the enclosed area corresponding to the first row of punching knives 2010a in the bottom mold 2020, the cut part can be effectively supported, and a supporting role can be played at the moment of punching, thereby avoiding unnecessary pulling between the covering membrane core board 10 and the first row of punching knives 2010a, thereby ensuring the quality and flatness of the cutting edge.

[0052] Furthermore, the size of the protrusion 2020a on one side is smaller than the size of the enclosed pattern of the first row of punching knives 2010a, preferably 0.05mm to 0.1mm. This small gap helps to avoid problems such as jamming between the first row of punching knives 2010a and the protrusion 2020a, ensuring smooth punching and cutting.

[0053] Furthermore, the cross-section of the protrusion 2020a is a right-angled trapezoid, with the hypotenuse of the trapezoid facing the top mold 2010, that is, by setting one side of the protrusion 2020a slightly higher than the other side, a progressive cutting is formed: in the feed stage, due to the height difference between the two sides, the covering membrane core board 10 first contacts the higher side, and then gradually transitions to the lower side. This method makes the punching action relatively soft, and can effectively avoid the traditional horizontal one-size-fits-all rigid method, which causes problems such as pulling or tearing of the covering membrane core board 10; in the retraction stage, also due to the height difference between the two sides, the two sides of the covering membrane core board 10 will not be pulled up at the same time, thereby reducing the risk of damage to the covering membrane core board 10, which is crucial for maintaining the quality and flatness of the cutting edge.

[0054] Optionally, the height difference of the hypotenuse of the trapezoid is 10μm to 50μm, which is within the flexibility range of the covering membrane core board 10. During punching, the board surface of the covering membrane core board 10 will not be broken or crushed due to uneven force, thereby ensuring the reliability of the flexible board connecting bridge 3020.

[0055] See also Figure 6 , Figure 6 Schematic diagram of the planar structure of the punched plate according to the embodiment of the present invention.

[0056] S30: Use the punching die 20 to perform alignment punching on the covering film core board 10 to form a groove body 3010 , and the opening corresponds to the position of the covering film core board 10 to form a flexible board connecting bridge 3020 , and the entire board forms a punched board 30 .

[0057] The flexible board connecting bridge 3020 is designed to ensure that the parts after punching still maintain a certain degree of connectivity, making the subsequent processing easier and more stable.

[0058] In this embodiment, the flexible plate connecting bridges 3020 of adjacent punched plates 30 in the panel structure are staggered. By staggering the flexible plate connecting bridges 3020 between adjacent punched plates 30, stress can be effectively dispersed to avoid stress concentration in a certain part and causing material rupture or deformation, which helps to improve the stability of the entire panel structure. In the subsequent forming process, such a structural design can increase the flexibility of the entire structure, allowing a larger deformation angle without easily breaking. Furthermore, it prevents the flexible plate connecting bridges 3020 from being arranged on the same longitudinal straight line to form a single linear connection, which is beneficial to dispersing the connection force effect and preventing non-connecting bridges from swinging during transportation and processing and causing the connecting bridge to tear.

[0059] Optionally, the offset distance between the flexible plate connecting bridges 3020 of adjacent punched plates 30 is 2 mm to 100 mm.

[0060] See also Figure 7 , and refer again to Figure 3 , Figure 7 Schematic diagram of the planar structure of the reinforcement plate according to the embodiment of the present invention.

[0061] S40: Take the reinforcing sheet and open a window corresponding to the slot body 3010 to form a reinforcing slot body 4010. The reinforcing slot body 4010 is composed of a plurality of intermittent slots. The intermittent positions form reinforcing connecting bridges 4020 to form a reinforcing plate 40. The reinforcing connecting bridges 4020 are staggered with the flexible plate connecting bridges 3020. That is, according to the following example, Figure 4 The reinforcing plate 40 is formed by processing according to the design data shown.

[0062] The edge size of the adjacent invalid area of ​​the reinforcement groove body 4010 of this embodiment is smaller than the edge size formed by the second row of punching cutters 2010b, which is equivalent to widening the invalid area of ​​the reinforcement plate 40. On the one hand, it provides a greater tolerance for the alignment and pressing of the reinforcement plate 40 and the punching plate 30, which is beneficial to improving the processing accuracy; on the other hand, it helps to bear more of the stress generated by the milling cutter during the forming process, reduce the stress concentration on the punching plate 30, and effectively avoid the pulling, wire drawing and other phenomena of the insulating medium layer or the covering film material layer of the flexible copper clad board, thereby ensuring the quality and reliability of the finished product.

[0063] Optionally, the edge size of the adjacent ineffective area of ​​the reinforcement slot 4010 is smaller than the edge size formed by the second row of punching cutters 2010b by 0.05mm to 2.95mm on one side.

[0064] In this embodiment, the reinforcing plate 40 is designed as a whole, and the reinforcing plate connecting bridge 4020 is connected to the process edge of the reinforcing plate 40, so that the reinforcing plates 40 are attached in batches, thereby improving the processing efficiency and the processing accuracy of the alignment and lamination.

[0065] Furthermore, the offset distribution distance 5010 between the reinforcement connecting bridge 4020 and the flexible board connecting bridge 3020 is greater than or equal to 50 μm, and the shortest offset distribution distance 5010 is controlled at 50 μm, that is, a safe distance is formed, so that the cutting processing of the reinforcement connecting bridge 4020 and the flexible board connecting bridge 3020 can be independently processed from each other, providing a processing basis for the subsequent process to perform different processing and cutting methods on the reinforcement connecting bridge 4020 and the flexible board connecting bridge 3020.

[0066] Optionally, the reinforcing plate 40 is made of aluminum sheet, stainless steel sheet, FR-4, polyimide or PTFE.

[0067] Optionally, the thickness of the reinforcement plate 40 is 0.1 mm to 3.0 mm.

[0068] See also Figure 8 、 Figure 9 and Figure 10 , Figure 8 Schematic diagram of the planar structure of a reinforced copper clad laminate according to an embodiment of the present invention; Figure 9 Schematic diagram of the planar structure of a circuit board according to an embodiment of the present invention; Figure 10 for Figure 9 Schematic diagram of the BB cross-section structure.

[0069] S50 : attaching the reinforcing plate 40 to the punched plate 30 to form the reinforced copper clad plate 50 , and then shaping it to form the circuit board 60 .

[0070] In this embodiment, the forming is performed by milling the reinforcing plate connecting bridge 4020 and laser cutting the flexible plate connecting bridge 3020 .

[0071] A milling cutter is used to cut the reinforcing plate connecting bridge 4020 because the reinforcing plate 40 is usually made of hard material. The use of a milling cutter can achieve high-precision and high-quality cutting effects. For the flexible plate connecting bridge 3020, laser cutting is selected. Laser cutting has the characteristics of non-contact processing and is suitable for thin and soft materials. It can complete fine cutting without damaging the surrounding area and is suitable for processing flexible materials that are easily deformed or damaged.

[0072] By selectively processing the different properties of the two materials, the reinforcement plate connecting bridge 4020 and the flexible board connecting bridge 3020, in different ways, it helps to form a high-precision molding line 1010, avoiding edge burrs, pulling, wire drawing and other problems of the molding line 1010, thereby improving the reliability of the circuit board 60.

[0073] It is worth noting that, since the circuit board 60 in the actual design and processing process is relatively precise, the actual structural diagram and the thickness between each layer, line width and other dimensions are all at the micron level. If the drawings in the specification are made according to the actual proportion, there will be a problem of unclear drawings. Therefore, in order to more clearly show the implementation process of the manufacturing method, the drawings of this embodiment are all schematic diagrams that enlarge the technical features, which do not represent the size of the actual structural diagram, nor do they represent enlarged drawings of the actual structural diagram in proportion.

[0074] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a large-size flexible circuit board that replaces a wiring harness type. The circuit board is processed using a panel structure formed by splicing flexible copper-clad laminates. The circuit board is designed with a forming line, and the area outside the forming line is an inactive area. The method is characterized by: The production method comprises the following steps: S10: The spacing between adjacent flexible copper-clad laminates in the panel structure is greater than or equal to 1.5 mm; a circuit pattern is formed on the flexible copper-clad laminate, and a covering film layer is formed to form a covering film core board; S20: manufacturing a punching die, wherein a top die of the punching die is designed with a first row of punching knives and a second row of punching knives, wherein the first row of punching knives corresponds to the forming line, and the second row of punching knives is arranged outside the forming line; The first row of punching knives and the second row of punching knives are provided with openings corresponding to each other; the spacing between the second row of punching knives and the first row of punching knives is 0.1 mm to 3.0 mm; a protrusion is provided in the bottom die of the punching die corresponding to the enclosed area of ​​the first row of punching knives; the size of one side of the protrusion is smaller than the size of the enclosed pattern of the first row of punching knives; the cross-section of the protrusion is a right-angled trapezoid, with the hypotenuse of the trapezoid facing the top die; S30: Using the punching die to perform alignment punching on the covering film core board to form a groove body, the opening corresponding to the position of the covering film core board forms a flexible board connection bridge, and the entire board forms a punched board; the flexible board connection bridges of adjacent punched boards in the panel structure are staggered; S40: Take a reinforcing sheet and cut windows corresponding to the slot body to form a reinforcing slot body, wherein the reinforcing slot body is composed of a plurality of intermittent through slots, and the positions of the intermittent slots form reinforcing connecting bridges to form a reinforcing plate; the reinforcing connecting bridges are staggered with the flexible plate connecting bridges; the edge size of the reinforcing slot body adjacent to the ineffective area is smaller than the edge size formed by the second row of punching cutters; S50: attaching the reinforcing plate to the punched plate, and then shaping it to form the circuit board; the shaping includes: milling the reinforcing plate connecting bridges and laser cutting the flexible board connecting bridges.

2. A method for manufacturing a large-size flexible circuit board of alternative wiring harness type according to claim 1, characterized in that: The offset distribution distance between the reinforcing connecting bridge and the flexible board connecting bridge is greater than or equal to 50 μm.

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