A flexible circuit board manufacturing method for golden finger high-fidelity signal transmission

Abstract

The application discloses a flexible circuit board manufacturing method for golden finger high-fidelity signal transmission, which comprises the following steps: taking a double-sided flexible copper-clad plate, manufacturing a blind hole, manufacturing a line pattern on both sides, connecting the blind hole with the golden finger line on the front side and the back reinforcing line on the back side, the line pattern on the back side further comprising a plate edge conducting line, manufacturing a dry film pattern on the front side, attaching a conductive film on the back side, covering the back reinforcing line with the conductive film, covering part of the plate edge conducting line with the conductive film, electroplating gold, removing the conductive film, silk printing resin ink on the back side, baking and curing, removing the film, and processing the flexible circuit board through a post-process; through the design of the back reinforcing line, the blind hole is connected with the golden finger line on the front side, the conductive film is connected to the plate edge conducting line on the plate edge, the gold lead is replaced, high-precision processing of the golden finger is realized, the back reinforcing line plays a reinforcing layer effect, resin ink is manufactured, and the strength and integrity of the reinforcing layer are improved.

Description

Technical Field

[0001] This invention relates to the field of circuit board and flexible circuit board manufacturing, and in particular to a method for manufacturing a flexible circuit board with high-fidelity signal transmission via gold fingers. Background Technology

[0002] For flexible circuit boards used in high-precision video or medical applications, higher processing and signal transmission accuracy are required. For flexible circuit boards with gold fingers, a "four-sided gold plating" process is generally required, meaning that the surface, top, and two sides of the gold fingers need to be covered with a gold layer. This ensures signal stability and improves the reliability of the gold fingers. During the gold plating process, leads need to be extended to the edge of the board. The copper layer pattern on the board edge is clamped by an electroplating fixture to generate current, which conducts electricity to the gold finger area, thus achieving the gold plating process. After the gold plating process is completed, the leads need to be removed to prevent short circuits in the gold fingers.

[0003] Meanwhile, for some flexible circuit boards that require small area and high precision, the gold fingers are designed as "offset gold fingers" to achieve the effect of laying more gold fingers in a smaller space. Therefore, the distance between the gold fingers of "offset gold fingers" and the circuit pattern on the board surface is closer, making it more difficult to set up leads.

[0004] Furthermore, since flexible circuit boards are relatively soft, a reinforcing layer is usually required on the back of the gold fingers to improve their support strength.

[0005] Currently, for flexible circuit boards that require "gold-plated on all four sides" and have "misaligned gold fingers", the general approach is to design the leads at the rear end of the circuit and extend them to the copper layer pattern on the edge of the board to create the leads and form a circuit connection. The reinforcement layer is generally achieved by independently attaching reinforcement sheets.

[0006] Current methods for manufacturing lead wires have several drawbacks. Due to the limited space and high precision requirements of the board, the lead wire design is complex, and the removal of the lead wires is difficult. Furthermore, the thickness of independently attached reinforcing sheets is relatively large, which affects the performance in small spaces and also poses the problem of reinforcing sheets easily falling off.

[0007] Therefore, in view of the above background and problems, there is a need to provide a method for manufacturing a flexible circuit board for high-fidelity signal transmission of gold fingers. Summary of the Invention

[0008] This invention addresses the challenges of manufacturing high-precision flexible circuit boards with "four-sided gold coating" and "misaligned gold fingers," which suffer from complex lead design, difficult lead removal, and thick, easily detachable independent reinforcement. The invention provides a method for manufacturing a flexible circuit board with high-fidelity signal transmission via gold fingers. The method includes the following steps:

[0009] S10: Take a double-sided flexible copper-clad board, the double sides being a front side and a back side, and make blind holes on the back side to form a blind hole circuit board;

[0010] S20: Fabricate circuit patterns on both sides of the blind via circuit board. The circuit pattern on the front side includes gold finger circuits, and the circuit pattern on the back side includes back reinforcement circuits. Multiple blind vias are respectively located within the pattern range of multiple back reinforcement circuits and connect the gold finger circuits and the back reinforcement circuits. The circuit pattern on the back side also includes a board edge conductive line located at one edge of the double-sided flexible copper-clad laminate. The entire board is processed to form a circuit pattern board.

[0011] S30: A dry film pattern is made on the front side to expose the gold finger circuit. A conductive film is attached to the back side, and the same conductive film covers the back side reinforcement circuit and partially covers the board edge conductive circuit. Electroplating is performed, and the gold finger circuit forms a gold finger. The whole process is processed to form a gold finger board.

[0012] S40: Remove the conductive film, screen print resin ink onto the area of ​​the back reinforcement circuit, and bake and cure it to form a resin layer reinforcement plate.

[0013] S50: The resin layer reinforcing plate is stripped, a cover film is attached to the front and back sides respectively, and the plate is formed according to the forming line of the finished product to form the flexible circuit board.

[0014] Furthermore, the blind via fabrication process involves: applying a dry film to both sides of the double-sided flexible copper-clad laminate to create a dry film pattern, exposing the blind via pattern on the back side, and then sequentially performing etching, laser drilling, and electroplating to form the blind via.

[0015] Furthermore, the adjacent gold finger lines are staggered vertically to form staggered gold finger lines.

[0016] Furthermore, the back reinforcement lines correspond to the gold finger line distribution.

[0017] Furthermore, the back reinforcement line forms an open-circuit pattern between adjacent lines of the gold finger line, and the edge extends to the molding line.

[0018] Furthermore, the conductive film is a double-layer film consisting of a carbon black micro-adhesive film and an insulating protective film, and the insulating protective film is made of one of PP, PE, PET, or PTFE.

[0019] Further, attaching the conductive film to the back side involves: screen printing an adhesive layer on the area outside the forming line on the back side, the adhesive layer being an acrylic adhesive layer or an epoxy resin adhesive layer, the adhesive layer avoiding the conductive lines on the board edge; and attaching the conductive film to the back side.

[0020] Optionally, attaching the conductive film to the back side comprises: taking a single-sided flexible copper-clad laminate and using punching or milling to create a whole-board pattern to form a single-sided copper-clad laminate pattern; taking a micro-adhesive film, the area of ​​which is larger than the single-sided copper-clad laminate pattern on one side; attaching the insulating dielectric layer of the single-sided copper-clad laminate pattern to one side of the adhesive layer of the micro-adhesive film to form the conductive film; attaching one side of the adhesive layer of the conductive film to the back side, with one end of the whole-board pattern contacting the board edge conductive lines and the other end contacting the back side reinforcing lines.

[0021] Furthermore, the back reinforcement line corresponds to the resin ink in the direction of the top of the gold finger and extends to the molding line.

[0022] Furthermore, the cover film layer attached to the front side is a window cover film layer for making windows corresponding to the gold fingers.

[0023] This invention's technical solution involves designing back-side reinforcement circuitry and connecting it to the gold finger circuitry on the front side via blind vias. A conductive film is then attached to the back side, connecting to the edge of the board to form a conductive network. During electroplating, the electroplating wire clamps the edge conductive network, connecting it to the back-side reinforcement circuitry via the conductive film, and then to the gold finger circuitry via blind vias, thus forming the gold finger circuitry. After electroplating, the conductive film is removed, completing the final manufacturing process. This effectively achieves the fabrication of a high-precision flexible circuit board with "four-sided gold plating" and "misaligned gold fingers." This method utilizes back-side reinforcing circuitry and blind vias with conductive films to replace direct front-side gold finger leads. This effectively avoids the problems of complex lead design, difficult processing, and hard removal, improving circuit board processing accuracy and machinability. Simultaneously, the back-side reinforcing circuitry acts as a reinforcing layer, further enhanced by resin ink application, increasing the strength and overall integrity of the reinforcing layer. This replaces the method of independently attaching reinforcing sheets, resulting in a thinner and more precise reinforcing layer. The overall processing flow is compatible with the preceding and following steps, forming an effective and feasible integrated processing workflow. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0025] Figure 1 This is a key process flow diagram of an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of a planar structure forming a blind hole on the back side according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the front planar structure of the circuit pattern board according to an embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram of the planar structure of the back side of the circuit pattern board according to an embodiment of the present invention;

[0029] Figure 5 This is an embodiment of the present invention. Figure 4 Schematic diagram of the AA section structure;

[0030] Figure 6 This is a schematic diagram of the planar structure of the back side of the gold finger plate according to an embodiment of the present invention;

[0031] Figure 7 This is an embodiment of the present invention. Figure 6 Schematic diagram of the BB cross-section structure;

[0032] Figure 8 This is a schematic diagram of another planar structure for fabricating the back side of the gold finger plate according to another embodiment of the present invention;

[0033] Figure 9 This is an embodiment of the present invention. Figure 8 A schematic diagram of the CC section structure;

[0034] Figure 10 This is a schematic diagram of the back side of the resin layer reinforcing plate according to an embodiment of the present invention.

[0035] Figure 11 This is an embodiment of the present invention. Figure 10 Schematic diagram of the DD cross-section structure;

[0036] Figure 12 This is a schematic diagram of the planar structure of the back side of a flexible circuit board as described in an embodiment of the present invention.

[0037] Figure 13This is an embodiment of the present invention. Figure 12 Schematic diagram of the EE cross-section structure;

[0038] Figure 14 This is a schematic diagram of the front planar structure of a flexible circuit board according to an embodiment of the present invention.

[0039] Explanation of icon numbers:

[0040] label name label name 10 Blind via circuit board 310B conductive film 100B Back copper layer 320 Molding line 110 blind hole 330A Front Dry Film Patterning Layer 120A Front Line 330B micromolecular membrane 120B Backside reinforcement circuit 340B Single-sided copper clad board graphics 130B Board edge conduction circuit 40 Resin layer reinforcement plate 20 Circuit diagram board 410 resin layer 100J Insulating dielectric layer 420 Electroplated gold layer 110A Goldfinger Circuit 50 Flexible circuit board 30 Gold finger plate 510 Back cover film 310A Front Dry Film Patterning Layer 520 Window covering film layer

[0041] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0043] It should be noted that all directional indications (such as up, down, left, right, front, back, inside, outside, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0044] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0046] Please see Figure 1 , Figure 1 This is a key process flow diagram for an embodiment of the present invention.

[0047] The method for manufacturing a flexible circuit board for high-fidelity signal transmission using gold fingers according to embodiments of the present invention includes: Figure 1The key manufacturing process is explained in detail step by step below.

[0048] Please see Figure 2 , Figure 2 This is a schematic diagram of a planar structure in which a blind hole 110 is formed on the back side according to an embodiment of the present invention.

[0049] Step S10:

[0050] A double-sided flexible copper-clad laminate is taken, with the double sides divided into a front side and a back side, and includes an insulating dielectric layer 100J. A blind via 110 is made on the back side to form a blind via circuit board 10.

[0051] In this embodiment, the blind via 110 is fabricated by: applying a dry film to both sides of the double-sided flexible copper-clad laminate, creating a dry film pattern, and exposing the pattern of the blind via 110 on the back side. That is, the pattern of the blind via 110 is fabricated on the copper layer 100B on the back side, and etching, laser drilling, and electroplating are performed sequentially to form the blind via 110.

[0052] First, blind vias 110 are fabricated on the board surface to connect the back reinforcement circuitry with the front gold finger circuitry 110A. Since high-precision circuit boards are generally thin, the blind vias 110 can be directly electroplated.

[0053] Please see Figures 3 to 5 , Figure 3 This is a schematic diagram of the front planar structure of the circuit pattern board according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the planar structure of the back side of the circuit pattern board according to an embodiment of the present invention; Figure 5 This is an embodiment of the present invention. Figure 4 A schematic diagram of the AA section structure.

[0054] Step S20:

[0055] The circuit pattern is fabricated on both sides of the blind via circuit board 10. The circuit pattern on the front side includes gold finger lines 110A and front line lines 120A. In this embodiment, the gold finger lines 110A are staggered gold finger lines 110A, that is, adjacent gold finger lines 110A are staggered vertically. The circuit pattern on the back side includes back reinforcement lines. Multiple blind vias 110 are respectively located within the pattern range of multiple back reinforcement lines and connect the gold finger lines 110A and the back reinforcement lines. Each back reinforcement line must have at least one blind via 110 corresponding to the gold finger lines 110A to ensure the conductivity between the back reinforcement lines and the front gold finger lines 110A during the electroplating process. After the circuit pattern is formed, the area where the copper layer is etched away exposes the insulating dielectric layer 100J.

[0056] The circuit pattern on the back also includes a board edge conductive line 130B located on one edge of the double-sided flexible copper clad laminate. The board edge conductive line 130B is a mandatory design. Generally, the board edge conductive line 130B that can be clamped is designed according to the distribution of the electroplating line clamps, so that the current of the electroplating line clamps can be effectively conducted to the board edge conductive line 130B.

[0057] The above processes are used to form a circuit board 20.

[0058] In one embodiment, the back reinforcement lines are distributed corresponding to the gold finger lines 110A. This corresponding distribution can effectively achieve the effect of conduction through the blind vias 110 and prevent misalignment or size difference between the gold finger pattern and the back reinforcement line pattern, which could cause damage to the insulating dielectric layer of the flexible circuit board during processing or application. Optionally, the side of each back reinforcement line corresponding to the gold finger line 110A is smaller than that of the gold finger line 110A. That is, each back reinforcement line falls completely within the range of each gold finger line 110A, which can also achieve the effect of conduction and prevention of damage to the insulating dielectric layer.

[0059] In one embodiment, an open-circuit pattern is made between adjacent lines of the back reinforcement line corresponding to the gold finger line 110A, and the edge extends to the molding line; that is, the back reinforcement line pattern corresponding to the gold finger line 110A area is disconnected from each other to prevent short circuit, while other areas extend to the molding line to form a larger area of ​​reinforcement layer support for the gold finger, which facilitates the insertion of the gold finger during application.

[0060] Please see Figures 6 to 9 , Figure 6 This is a schematic diagram of the planar structure of the back side of the gold finger plate according to an embodiment of the present invention; Figure 7 This is an embodiment of the present invention. Figure 6 Schematic diagram of the BB cross-section structure; Figure 8 This is a schematic diagram of another planar structure for fabricating the back side of the gold finger plate according to another embodiment of the present invention; Figure 9 This is an embodiment of the present invention. Figure 8 A schematic diagram of the CC section structure.

[0061] Step S30:

[0062] A dry film pattern is created on the front side, exposing the gold finger circuit 110A. A dry film layer is then attached to the front side and a dry film pattern is created, forming a front dry film pattern layer 310A. A conductive film 310B is attached to the back side, and the same conductive film 310B covers the back reinforcing circuit and partially covers the edge conductive circuit 130B. Electroplating is then performed to form an electroplated gold layer 420, and the gold finger circuit 110A forms the gold finger 420A. The entire process forms the gold finger board 30.

[0063] This embodiment uses a conductive film 310B to form an electrical connection between the back reinforcement line and the board edge conductive line 130B (further through a blind via 110 to form an electrical connection between the back reinforcement line and the gold finger line 110A), instead of directly fabricating electroplated gold leads on the circuit pattern. On the one hand, this avoids the problem of complex lead design and fabrication when the circuit density is too high and the circuit precision requirements are high. On the other hand, the conductive film 310B can be easily removed after the electroplating process is completed, without the need to use pattern etching (dry film application → exposure → development → etching → film removal) to remove the leads, which greatly simplifies the process and avoids the large expansion and contraction effects on the board body caused by multiple pattern etching.

[0064] In this embodiment, the conductive film 310B is a double-layer film consisting of a carbon black micro-adhesive film and an insulating protective film, and the insulating protective film is made of one of PP, PE, PET, or PTFE.

[0065] Carbon black microfilm has good electrical conductivity, which can ensure the current transmission during the gold plating process. Using an insulating protective film to protect the surface effectively prevents the carbon black microfilm from being plated with gold during the gold plating process.

[0066] As an alternative, the conductive film 310B is attached to the back side by: screen printing an adhesive layer on the area outside the forming line on the back side, the adhesive layer being an acrylic adhesive layer or an epoxy resin adhesive layer, the adhesive layer avoiding the board edge conductive line 130B; and attaching the conductive film 310B to the back side.

[0067] To ensure a stronger bond between the conductive film 310B and the back surface (or when the conductive film 310B lacks adhesive properties), an adhesive layer is applied to the ineffective area outside the forming line. This adhesive layer adheres the conductive film 310B to the edge area of ​​the back surface, creating a reinforcing contact between the conductive film 310B and the back surface. The conductive film 310B can then be removed using laser-controlled milling to the thickness of the conductive film 310B, or by punching or milling in subsequent forming processes. (It is worth noting that if laser-controlled milling is used to remove the conductive film 310B, the main processing flow is: laser-controlled milling → removal.) Conductive film 310B → Backside screen printing resin ink → Double-sided cover film application → Overall molding; If the conductive film 310B is removed by subsequent direct molding, the main processing flow is: first apply the cover film on the gold finger side, then mold, then make the backside screen printing resin ink and apply the backside cover film; If the conductive film 310B is adhered to the adhesive layer, the board edge conductive line 130B needs to be extended. The board edge conductive line 130B needs to form three areas in sequence: exposed area (conductive contact with the electroplating line clamp), adhesive area, and conductive film 310B contact area, to ensure that the sealing of the adhesive and the contact conductivity of the conductive film 310B are satisfied at the same time.

[0068] As an alternative method, attaching the conductive film to the back side is as follows: First, fabricate the conductive film: Take a single-sided flexible copper-clad laminate and use punching or milling to create a full-board pattern, forming a single-sided copper-clad laminate pattern 340B; Take a micro-adhesive film 330B, the area of ​​which is larger on one side than the single-sided copper-clad laminate pattern 340B, and attach the insulating dielectric layer of the single-sided copper-clad laminate pattern 340B to one side of the adhesive layer of the micro-adhesive film 330B to form a conductive film; Second, attach the conductive film: Attach one side of the conductive film to the back side, with one end of the full-board pattern contacting the board edge conductive line 130B, and the other end contacting (partially covering) the back reinforcement line.

[0069] A conductive film is fabricated using a single-sided flexible copper-clad laminate and a micro-adhesive film 330B. The single-sided flexible copper-clad laminate is used to form a single-sided copper-clad laminate pattern 340B, which forms a connection between the back reinforcement circuit and the board edge conductive circuit 130B. On the one hand, this makes the fabrication of the conductive circuit pattern more flexible and meets the conductivity requirements of different gold finger circuits 110A. That is, it can be understood as forming an auxiliary lead network independent of the flexible circuit board itself. On the other hand, it enables batch automated processing, making the application of the conductive film more precise, efficient and reliable.

[0070] Please see Figure 10 and Figure 11 , Figure 10 This is a schematic diagram of the back side of the resin layer reinforcing plate according to an embodiment of the present invention. Figure 11 This is an embodiment of the present invention. Figure 10 A schematic diagram of the DD cross-section structure.

[0071] Step S40:

[0072] Remove the conductive film 310B, screen print resin ink onto the area of ​​the reinforcing circuit on the back side, and bake and cure it to form a resin layer 410. The whole process is then used to form a resin layer reinforcing plate 40.

[0073] In this embodiment, the resin ink corresponding to the tip direction of the gold finger in the back reinforcement line extends to the molding line.

[0074] The resin ink is screen-printed and baked to cure, forming further support from the back to the front gold finger area, and improving the integrity of the support performance of the back reinforcement circuit, preventing the problem of tearing of the insulating dielectric layer of the flexible circuit board due to insufficient reinforcement support; the resin ink extends to the forming line, which can increase the support area and reduce the "steps" formed by each layer.

[0075] Please see Figures 12 to 14 , Figure 12 This is a schematic diagram of the planar structure of the back side of a flexible circuit board as described in an embodiment of the present invention. Figure 13 This is an embodiment of the present invention. Figure 12 Schematic diagram of the EE cross-section structure; Figure 14 This is a schematic diagram of the front planar structure of a flexible circuit board according to an embodiment of the present invention.

[0076] Step S50:

[0077] The resin layer reinforcing plate 40 is stripped of its original coating, and a cover film is attached to the front and back sides respectively. The plate is then shaped according to the forming lines of the finished product to form a flexible circuit board 50.

[0078] In this embodiment, a back cover film layer 510 is attached to the back side, and a cover film layer 520 is attached to the front side to create a window for the gold finger.

[0079] The front cover film has a window to expose the gold fingers, which, with the support of the back reinforcing circuit and resin layer 410, form a gold finger with high front reliability.

[0080] It is worth noting that, due to the high precision of the circuit boards in the actual design and manufacturing process, the actual structural diagrams and dimensions such as the thickness of each layer and the width of the lines are at the micrometer level. For example, the thickness of each layer is generally between 5μm and 50μm. If the accompanying drawings in the instruction manual are made according to the actual scale, there will be a problem of unclear illustrations. Therefore, in order to more clearly show the implementation process of the manufacturing method, the accompanying drawings in this embodiment are all enlarged schematic diagrams of the technical features, and do not represent the size of the actual structural diagram, nor do they represent enlarged views of the actual structural diagram at the same scale.

[0081] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural transformations made using the contents of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. A method for manufacturing a flexible circuit board for high-fidelity signal transmission via gold fingers, characterized in that, The manufacturing method includes the following steps: S10: Take a double-sided flexible copper-clad board, the double sides being a front side and a back side, and make blind holes on the back side to form a blind hole circuit board; S20: Fabricate circuit patterns on both sides of the blind via circuit board, wherein the circuit pattern on the front side includes gold finger circuits and the circuit pattern on the back side includes back reinforcement circuits. The multiple blind holes are respectively located within the graphic range of the multiple back reinforcement lines, and connect the gold finger lines and the back reinforcement lines; The circuit pattern on the back side also includes a board edge conductive line located at one edge of the double-sided flexible copper clad laminate. The entire process is used to form the circuit board. S30: A dry film pattern is made on the front side to expose the gold finger circuit. A conductive film is attached to the back side, and the same conductive film covers the back side reinforcement circuit and partially covers the board edge conductive circuit. Electroplating is performed, and the gold finger circuit forms a gold finger. The whole process is processed to form a gold finger board. S40: Remove the conductive film, screen print resin ink onto the area of ​​the back reinforcement circuit, and bake and cure it to form a resin layer reinforcement plate. S50: The resin layer reinforcing plate is stripped, a cover film is attached to the front and back sides respectively, and the plate is formed according to the forming line of the finished product to form the flexible circuit board.

2. The method for manufacturing a flexible circuit board for high-fidelity signal transmission via gold fingers as described in claim 1, characterized in that, The process of creating the blind hole is as follows: Dry film is applied to both sides of the double-sided flexible copper clad laminate to create a dry film pattern. The pattern of the blind hole is exposed on the back side. The blind hole is then formed by etching, laser drilling, and electroplating.

3. The method for manufacturing a flexible circuit board for high-fidelity signal transmission using gold fingers as described in claim 1, characterized in that, The adjacent gold finger lines are staggered vertically to form staggered gold finger lines.

4. The method for manufacturing a flexible circuit board for high-fidelity signal transmission via gold fingers as described in claim 1, characterized in that, The back reinforcement lines correspond to the gold finger line distribution.

5. The method for manufacturing a flexible circuit board for high-fidelity signal transmission via gold fingers as described in claim 1, characterized in that, The back reinforcement line forms an open circuit pattern between adjacent lines of the gold finger line, and the edge extends to the molding line.

6. The method for manufacturing a flexible circuit board for high-fidelity signal transmission via gold fingers as described in claim 1, characterized in that, The conductive film is a double-layer film consisting of a carbon black micro-adhesive film and an insulating protective film, and the insulating protective film is made of one of PP, PE, PET, or PTFE.

7. A method for manufacturing a flexible circuit board for high-fidelity signal transmission via gold fingers as described in claim 1 or 6, characterized in that, The process of attaching the conductive film to the back side involves: screen printing an adhesive layer on the area outside the forming line on the back side, wherein the adhesive layer is an acrylic adhesive layer or an epoxy resin adhesive layer, and the adhesive layer avoids the conductive lines on the board edge; and then attaching the conductive film to the back side.

8. The method for manufacturing a flexible circuit board for high-fidelity signal transmission via gold fingers as described in claim 1, characterized in that, The process of attaching the conductive film to the back side is as follows: Take a single-sided flexible copper-clad laminate and use punching or milling to create a whole board pattern, forming a single-sided copper-clad laminate pattern. Take a micro-adhesive film, the area of ​​which is larger than the single-sided copper clad laminate pattern on one side. Attach the insulating dielectric layer of the single-sided copper clad laminate pattern to one side of the adhesive layer of the micro-adhesive film to form the conductive film. One side of the adhesive layer of the conductive film is attached to the back side, one end of the whole board pattern contacts the conductive line on the edge of the board, and the other end contacts the reinforcing line on the back side.

9. The method for manufacturing a flexible circuit board for high-fidelity signal transmission via gold fingers as described in claim 1, characterized in that, The back reinforcement line corresponds to the resin ink at the tip of the gold finger and extends to the molding line.

10. The method for manufacturing a flexible circuit board for high-fidelity signal transmission via gold fingers as described in claim 1, characterized in that, The cover film layer attached to the front is a window cover film layer for making windows corresponding to the gold fingers.

Images