Bending-resistant FPC (Flexible Printed Circuit) with block metal circuit and manufacturing method of bending-resistant FPC

Abstract

The invention discloses a bending-resistant FPC (Flexible Printed Circuit) with a block metal circuit and a manufacturing method thereof. The method comprises the following steps: providing a circuit board substrate; wherein a bending circuit area and a non-bending circuit area are preset on the circuit board substrate; performing circuit manufacturing on the circuit board substrate, forming a non-bending circuit layer on the non-bending circuit area, and making the bending circuit area have no circuit to obtain a semi-finished circuit board; and providing a block metal material, and forming a block metal circuit layer electrically connected with the non-bending circuit layer on the circuit board semi-finished product based on the bending circuit area to obtain the flexible circuit board. Based on the block metal circuit, the flexible printed circuit board has more excellent bending resistance, and the bending life of the FPC can be effectively prolonged.

Description

Technical Field

[0001] This invention relates to the field of flexible printed circuit boards, specifically to a bend-resistant FPC with segmented metal circuitry and its manufacturing method. Background Technology

[0002] As smart terminals evolve towards lightweight and highly integrated designs, and with the rapid development of consumer electronics, automotive electronics, medical and robotics fields, the bending performance of flexible printed circuits (FPCs) has become an increasingly important performance characteristic for many electronic products. However, traditional FPCs are prone to failure in bending applications due to limitations in materials and processes, resulting in a relatively low bending lifespan.

[0003] Therefore, there is an urgent need for a new technical solution to improve the bending life of FPC. Summary of the Invention

[0004] In view of this, the present invention provides a bend-resistant FPC with segmented metal circuitry and a method for manufacturing the same, in order to solve the problems of low bending life of existing FPCs.

[0005] This invention provides a method for manufacturing a bend-resistant FPC with segmented metallic circuitry, the method comprising: A circuit board substrate is provided; wherein, the circuit board substrate has a pre-defined bending circuit area and a non-bending circuit area; The circuit board substrate is fabricated to form a non-bending circuit layer on the non-bending circuit area of ​​the circuit board substrate, and the bending circuit area is free of circuits, thus obtaining a semi-finished circuit board. A segmented metal material is provided, and based on the bent circuit area, a segmented metal circuit layer electrically connected to the non-bent circuit layer is formed on the circuit board semi-finished product to obtain a flexible circuit board.

[0006] Optionally, the segmental metal material includes any one of copper, silver, and gold.

[0007] Optionally, the block metal material is specifically a liquid metal slurry; Provide a segmented metal material, and based on the bent circuit area, form a segmented metal circuit layer on the circuit board semi-finished product that is electrically connected to the non-bent circuit layer, including: The metal paste is provided and screen-printed onto the bent circuit area of ​​the circuit board semi-finished product to form a segmented metal coating that is electrically connected to the non-bent circuit layer. The segment metal coating on the circuit board semi-finished product is baked and cured to obtain the segment metal circuit layer.

[0008] Optionally, before forming a block metal circuit layer on the circuit board semi-finished product, the method further includes: Based on the bent line area, a screen printing template for printing the metal paste is made.

[0009] Optionally, the block metal material specifically includes liquid metal slurry and solid metal wire; Provide a segmented metal material, and based on the bent circuit area, form a segmented metal circuit layer on the circuit board semi-finished product that is electrically connected to the non-bent circuit layer, including: Provide the metal wire with a preset wire diameter, fix the metal wire to the bent circuit area of ​​the circuit board semi-finished product, so that the metal wire is electrically connected to the non-bent circuit layer; A metal paste is provided, and the metal paste is applied to the metal wire in the bent circuit area by a dot coating method to form a segmented metal coating. The segment metal coating on the circuit board semi-finished product is baked and cured to obtain the segment metal circuit layer.

[0010] Optionally, the preset wire diameter ranges from 10 to 50 μm.

[0011] Optionally, during the baking and curing process of the block metal coating, the temperature range is 130~180℃ and the time range is 30~90min.

[0012] Optionally, the circuit board substrate is fabricated to form a non-bending circuit layer on the non-bending circuit area of ​​the circuit board substrate, thereby eliminating the circuit in the bending circuit area, resulting in a semi-finished circuit board, comprising: The non-bending circuit area and the bending circuit area of ​​the circuit board substrate are simultaneously etched to form a non-bending circuit layer on the non-bending circuit area of ​​the circuit board substrate, and to make the bending circuit area free of circuits, thereby obtaining the circuit board semi-finished product.

[0013] Optionally, after forming a block metal circuit layer on the circuit board semi-finished product, the method further includes: An outer circuit substrate is provided; wherein, the outer circuit substrate has an outer bending circuit area; Using the same method as forming the segmented metal circuit layer on the circuit board semi-finished product, an outer layer segmented metal circuit is formed on the outer layer bent circuit area of ​​the outer layer circuit substrate to obtain an outer layer circuit board. Based on the bent circuit area and the outer bent circuit area, the outer circuit board and the circuit board semi-finished product having the segmented metal circuit layer are glued and pressed together.

[0014] Optionally, the circuit board substrate is any one of a single-sided board, a double-sided board, and a multilayer board, and / or the outer circuit substrate is a single-sided board or a double-sided board.

[0015] In addition, the present invention also provides a bend-resistant FPC with segmented metal circuitry, which is manufactured using the aforementioned manufacturing method.

[0016] The beneficial effects of this invention are as follows: On the circuit board substrate, the entire circuit is divided into a bending circuit area and a non-bending circuit area. The circuit is fabricated first, and a non-bending circuit layer is fabricated in the non-bending circuit area, so that there are no circuits in the bending circuit area. This makes it easier to fabricate the circuits in the bending circuit area separately, and thus facilitates the formation of a segmented circuit. During the fabrication of the circuits in the bending circuit area, the provided segmented metal material is used to form segmented metal circuits that are electrically connected to the non-bending circuit layer. The flexible circuit board with this segmented form has better bending resistance, thereby effectively improving the overall bending resistance of the FPC and extending its bending life. Attached Figure Description

[0017] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings: Figure 1 A flowchart of a method for manufacturing a bend-resistant FPC with segmented metal circuitry according to Embodiment 1 of the present invention is shown; Figure 2A This shows a front view structural diagram of the circuit board substrate in Embodiment 1 of the present invention; Figure 2B A cross-sectional view of the circuit board substrate in Embodiment 1 of the present invention is shown; Figure 3A This shows a front view structural diagram of the circuit board semi-finished product obtained after etching in Embodiment 1 of the present invention; Figure 3B A cross-sectional view of the semi-finished circuit board obtained after etching in Embodiment 1 of the present invention is shown. Figure 4A This shows a front view structural diagram of a circuit board semi-finished product with a segmented metal circuit layer formed in Embodiment 1 of the present invention; Figure 4B This shows a cross-sectional view of a semi-finished circuit board with a segmented metal circuit layer formed in Embodiment 1 of the present invention. Figure 5A This diagram illustrates a process flow model for forming a block metal circuit layer in the first optional embodiment of the present invention. Figure 5B This diagram illustrates a process flow model for forming a segmented metal circuit layer in the second optional embodiment of Embodiment 1 of the present invention. Figure 6A This is a cross-sectional view of an outer circuit board with an outer layer of intercalary metal circuitry laminated onto one side of an inner circuit board, according to Embodiment 1 of the present invention. Figure 6B This is a cross-sectional view of an embodiment of the present invention, in which an outer circuit board with an outer layer of inter-layer metal circuitry is pressed onto both sides of an inner circuit board. Figure 7A This illustrates the first embodiment of the present invention based on Figure 6A A cross-sectional view of a flexible circuit board obtained by covering the circuit board structure shown with a protective film. Figure 7B This illustrates the first embodiment of the present invention based on Figure 6A The diagram shows a cross-sectional view of a flexible circuit board obtained by covering the circuit board structure with a protective film.

[0018] The labels in the attached figures are explained as follows: 1. Insulating layer; 2. Conductive layer; 3. Non-bending circuit layer; 4. Intercalated metal circuit layer; 5. Outer copper layer; 6. Outer PI layer; 7. Outer intercalated metal circuit layer; 8. Protective film; 9. Bonding adhesive; 100. Bending circuit area; 200. Non-bending circuit area. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 This embodiment provides a method for manufacturing a bend-resistant FPC with segmented metal circuitry, such as... Figure 1 As shown, the method includes: S1: Provide a circuit board substrate; wherein, the non-bending circuit area of ​​the circuit board substrate is pre-formed with a bending circuit area and a non-bending circuit area; S2: The circuit board substrate is fabricated to form a non-bending circuit layer on the circuit board substrate, and the bending circuit area is free of circuits, to obtain a semi-finished circuit board. S3: Provide a segmented metal material, and based on the bent circuit area, form a segmented metal circuit layer that is electrically connected to the non-bent circuit layer on the circuit board semi-finished product to obtain a flexible circuit board.

[0021] In this embodiment, the entire circuitry is divided into a bent circuitry area and a non-bent circuitry area on the circuit board substrate. The circuitry is fabricated first, and a non-bent circuitry layer is created in the non-bent circuitry area, leaving the bent circuitry area without any circuitry. This facilitates the subsequent separate fabrication of the circuitry in the bent circuitry area, thereby enabling the formation of a segmented circuitry. During the fabrication of the circuitry in the bent circuitry area, the provided segmented metal material is used to create segmented metal circuitry that is electrically connected to the non-bent circuitry layer. The flexible circuit board with this segmented form has superior bending resistance, thereby effectively improving the overall bending resistance of the FPC and extending its bending life.

[0022] The following is a detailed description of each step of the manufacturing method in this embodiment.

[0023] In this embodiment S1, the circuit board substrate is any one of single-sided board, double-sided board, and multilayer board.

[0024] The circuit board substrate of this embodiment can be any of single-sided, double-sided, and multilayer boards. When manufacturing the circuit layers, they can all be partitioned according to the manufacturing method of this embodiment to form an FPC with segmented metal circuits. The manufacturing method of this embodiment has a wide range of applications.

[0025] It should be understood that a single-sided board is a flexible board substrate with a single conductive layer, a double-sided board is a flexible board substrate with two conductive layers, and a multilayer board is a flexible board substrate composed of single-sided and double-sided boards. The specific layer structure is the conventional structure in FPC, and will not be described in detail here.

[0026] For ease of explanation, this embodiment uses a double-sided panel as an example, and its main view structure and cross-sectional view structure are as follows: Figure 2A and Figure 2B As shown, 1 is the insulating layer (usually polyimide PI, polyethylene terephthalate PET, etc.), and 2 is the conductive layer (usually a copper layer). Figure 2A and Figure 2B In the diagram, 100 represents the bent circuit area, and 200 represents the non-bent circuit area. The bent circuit area 100 and the non-bent circuit area 200 together constitute the entire circuit area of ​​the circuit board substrate.

[0027] It should be understood that the non-circuit area (i.e., the area where no circuits are made) in a double-sided board is not shown in the diagram.

[0028] In this embodiment S1, the specific location and size of the bent and non-bent circuit areas on the circuit board substrate depend on the specific product design.

[0029] Preferably, embodiment S2 includes: The non-bending circuit area and the bending circuit area of ​​the circuit board substrate are simultaneously etched to form a non-bending circuit layer on the non-bending circuit area of ​​the circuit board substrate, and to make the bending circuit area free of circuits, thereby obtaining the circuit board semi-finished product.

[0030] Etching on the non-bending circuit areas of the circuit board substrate allows for the removal of conductive layers in areas that are not circuits, while retaining the conductive layers in areas that are circuits. This results in a non-bending circuit layer that meets design requirements (including circuit layout, line width, and line spacing). Simultaneously, etching is also performed on the bending circuit areas of the circuit board substrate to eliminate the circuits. This is equivalent to etching away the conductive layer in the entire bending circuit area, making it easier to fabricate a segmented metal circuit layer in the etched conductive layer area using a new manufacturing process, resulting in an FPC product with higher bending resistance.

[0031] for Figure 2A and Figure 2B The double-sided board shown has its main view and cross-sectional view structures after etching, as shown in the figures below. Figure 3A and Figure 3B As shown. In Figure 3A and Figure 3B In the middle, 3 is the non-bending line layer 2 formed by etching the conductive layer 2 of the non-bending line region 200.

[0032] It should be understood that etching refers to etching the conductive layer in the circuit board substrate, which typically includes processes such as applying dry film, exposure, development, and removing dry film.

[0033] Preferably, in this embodiment S3, the segmental metal material includes any one of copper, silver, and gold.

[0034] Silver and gold typically have higher elongation at break and elongation at break than copper. They also have higher bending fatigue limits, and their smooth surfaces help reduce the skin effect. Therefore, using silver or gold as the intercalation metal material to fabricate the intercalation metal circuit layer, replacing the traditional copper wires in the bending area, can effectively improve the tensile strength of the circuit in the bending area, thereby improving the overall bending strength of the FPC and extending its bending life. Similarly, using copper as the intercalation metal material and employing an intercalation metal circuit layer fabrication process instead of the traditional etching process can also improve the tensile strength of the circuit in the bending area to some extent, thus extending the overall bending life of the FPC.

[0035] The block metal material of the above components can be a liquid metal slurry or a solid metal wire.

[0036] In the first optional embodiment, the segment metal material is specifically a liquid metal paste; then in S3, based on the bent circuit area, forming a segment metal circuit layer electrically connected to the non-bent circuit layer on the circuit board semi-finished product includes: S3A1: The metal paste is provided and printed on the bent circuit area of ​​the circuit board semi-finished product by screen printing to form a segment metal coating that is electrically connected to the non-bent circuit layer. S3A2: The segment metal coating on the circuit board semi-finished product is baked and cured to obtain the segment metal circuit layer.

[0037] The above steps represent the first embodiment of fabricating segmented metal circuits. Using screen printing to print liquid metal paste into a segmented metal coating allows for low-temperature processing and process simplification, reducing manufacturing costs to some extent. It also enables mass production while ensuring the bending resistance of the segmented metal circuit layer in the bending area. During printing, the segmented metal coating is electrically connected to the non-bending circuit layer, ensuring the entire circuit layer is electrically connected and thus guaranteeing its functionality. After the segmented metal coating is printed, it is baked and cured. This removes moisture and volatiles from the coating, improving circuit stability and reliability, and also enhances the adhesion between the segmented metal coating and the circuit board semi-finished product, improving product quality.

[0038] Specifically, prior to S3A1, the method also included: S3A3: Based on the bent line area, a screen printing template for printing the metal paste is made.

[0039] By creating a screen printing template based on the curved line area, the metal paste can be accurately printed onto the curved line area during subsequent printing, and a segmented metal coating that meets the design requirements (including the thickness, width, and spacing of the segmented metal coating).

[0040] Specifically, during the baking and curing process of the block metal coating in S3A2, the temperature range is 130~180℃ and the time range is 30~90min.

[0041] for Figure 2A and Figure 2B The double-sided board shown, using the steps described in the first optional embodiment above, forms a circuit board semi-finished product with a segmented metal circuit layer, and its main view structure and cross-sectional view structure are as follows: Figure 4A and Figure 4B As shown. In 4A and Figure 4B In the middle, 4 is the segmented metal circuit layer formed by the bent circuit area 100.

[0042] The process flow diagram for forming the block metal circuit layer in the first optional embodiment described above is shown below. Figure 5A As shown.

[0043] In a second optional embodiment, the segmented metal material specifically includes a liquid metal slurry and a solid metal wire; then in S3, based on the bent circuit area, forming a segmented metal circuit layer electrically connected to the non-bent circuit layer on the circuit board semi-finished product includes: S3B1: Provide the metal wire with a preset wire diameter, fix the metal wire to the bent circuit area of ​​the circuit board semi-finished product, so that the metal wire is electrically connected to the non-bent circuit layer. S3B2: Provide a metal paste, and apply the metal paste to the metal wire in the bent circuit area by a dot coating method to form a segmented metal coating; S3B3: The segment metal coating on the circuit board semi-finished product is baked and cured to obtain the segment metal circuit layer.

[0044] The above steps represent the second embodiment of fabricating segmented metal circuits. First, solid metal wires are fixed to the bent circuit area. This allows for electrical connection with the non-bent circuit layer, ensuring the functionality of the entire circuit layer. Secondly, the metal wires serve as the circuit framework for the bent area, pre-determining the direction and position of the entire segmented metal circuit layer. This also facilitates subsequent metal paste application, preventing deformation or displacement during application and improving the accuracy of the application, thereby enhancing the fabrication precision of the segmented metal circuit layer. After fixing the metal wires, a dotting process is used to apply the metal paste onto the wires. This allows for precise control of the thickness, width, and spacing of the segmented metal coating, as well as precise control of material costs and processing time. It enables precise, localized processing, offering greater flexibility and adaptability to precision FPC products. Similar to the first optional embodiment, after the segmented metal coating is formed, it is baked and cured. This removes moisture and volatiles from the segmented metal coating, improving the stability and reliability of the circuit, and enhancing the adhesion between the segmented metal coating and the circuit board semi-finished product, thus improving product quality.

[0045] Specifically, in S3B1, the diameter of the metal wire ranges from 10 to 50 μm.

[0046] Specifically, similar to step S3A2, in step S3B3, during the baking and curing process of the block metal coating, the temperature range is 130~180℃ and the time range is 30~90min.

[0047] for Figure 2A and Figure 2BThe double-sided board shown, using the steps described in the second optional embodiment above, forms a circuit board semi-finished product with a segmented metal circuit layer, and its main view structure and cross-sectional structure are also as shown in the figure. Figure 4A and Figure 4B As shown.

[0048] The process flow diagram for forming the block metal circuit layer in the second optional embodiment described above is shown below. Figure 5B As shown.

[0049] Preferably, in S3, after forming a segmented metal circuit layer on the circuit board semi-finished product, the method further includes: S4: Provide an outer layer circuit substrate; wherein, the outer layer circuit substrate is provided with an outer layer bent circuit area; S5: Using the same method as forming the segmented metal circuit layer on the circuit board semi-finished product, an outer layer segmented metal circuit is formed on the outer layer bent circuit area of ​​the outer layer circuit substrate to obtain an outer layer circuit board. S6: Based on the bent circuit area and the outer bent circuit area, the outer circuit board and the circuit board semi-finished product with the segmented metal circuit layer are glued and pressed together.

[0050] The circuit board structure formed in steps S1 to S3 (i.e., the circuit board semi-finished product with the segmented metal circuit layer) is used as the inner circuit board. On this basis, an outer circuit substrate is provided, and the outer segmented metal circuit is also formed on the outer circuit substrate in the same way as the inner circuit board. The inner and outer layers are then glued and pressed together to form the final FPC product. On the one hand, this can make the circuit in the bending area of ​​the entire FPC product have excellent bending resistance, further improving the bending life of the FPC. On the other hand, it can make the formed FPC product a multi-layer structure, which can be adapted to complex application scenarios and facilitate integration and functional expansion.

[0051] Specifically, in S4, the outer circuit substrate is a single-sided or double-sided board.

[0052] Specifically, the method for forming the outer layer segment metal circuit in S5 is the same as the method for forming the segment metal circuit layer in the aforementioned steps, and will not be repeated here.

[0053] Specifically, in S5, the number of outer circuit boards with outer layer segmented metal lines is one or two. When the number of outer circuit boards with outer layer segmented metal lines is one, the circuit board structure formed in the aforementioned steps S1~S3 (i.e., the circuit board semi-finished product with segmented metal line layers) is used as the inner circuit board, and the outer circuit board with outer layer segmented metal lines is pressed onto one side of the inner circuit board using bonding adhesive (e.g., ...). Figure 6AAs shown); when there are two outer circuit boards with outer segment metal lines, similarly, the circuit board structure formed in the aforementioned steps S1~S3 (i.e., the circuit board semi-finished product with segment metal lines) is used as the inner circuit board, and the two outer circuit boards are respectively pressed onto the two sides of the inner circuit board using bonding adhesive (e.g. Figure 6B (As shown). In Figure 6A and Figure 6B In the diagram, 5 is the outer copper layer, 6 is the outer PI layer, and 7 is the outer embedded metal circuit.

[0054] It should be understood that the pressure bonding in S6 can be achieved using conventional processes; specific details will not be elaborated here.

[0055] Preferably, after forming a segmented metal circuit layer on the circuit board semi-finished product, the method further includes: S7: Cover the semi-finished circuit board with a protective film to obtain a flexible circuit board.

[0056] By covering the circuit board with a protective film, the semi-finished circuit board with the segmented metal circuit layer can be protected, increasing its electrical insulation and mechanical strength, and facilitating subsequent assembly and testing.

[0057] It should be understood that the protective film covering in the S7 can be achieved using conventional processes; specific details will not be elaborated here.

[0058] for Figure 6A The circuit board structure shown is illustrated in the figure. The cross-sectional structure of the flexible circuit board obtained by covering it with a protective film is shown below. Figure 7A As shown; for Figure 6B The circuit board structure shown is illustrated in the figure. The cross-sectional structure of the flexible circuit board obtained by covering it with a protective film is shown below. Figure 7B As shown. In Figure 7A and Figure 7B In the middle, 8 represents the protective film.

[0059] To further illustrate the manufacturing method of this embodiment, this embodiment provides the following two specific manufacturing examples and one comparative example.

[0060] Example 1: (1) The double-sided board is etched on both sides to form a non-bending circuit layer. The line width / spacing of the circuit in this circuit layer is 100μm / 100μm, and the entire non-bending circuit layer is designed to be 2cm long. At the same time, the conductive layer in the bending circuit area is etched away, leaving no circuit.

[0061] (2) Use screen printing to print silver paste on both sides of the bent line area of ​​the above double-sided panel, and bake the silver paste to cure.

[0062] (3) The single-sided PCB is etched to form an outer non-bent circuit layer. The line width / spacing of the circuit in this circuit layer is 100μm / 100μm. The outer bent circuit area is also designed to be 2cm long. The conductive layer of the outer bent circuit area is etched away, leaving no circuit.

[0063] (4) On the single-sided panel mentioned above, silver paste is screen-printed and then baked to cure.

[0064] (5) Apply adhesive to the single-sided and double-sided boards after the circuit fabrication is completed.

[0065] (6) Double-sided protective film is laminated to obtain sample 1.

[0066] Example 2: (1) The double-sided board is etched on both sides to form a non-bending circuit layer. The line width / spacing of the circuit in this circuit layer is 100μm / 100μm, and the entire non-bending circuit layer is designed to be 2cm long. At the same time, the conductive layer in the bending circuit area is etched away, leaving no circuit.

[0067] (2) Take a silver wire with a length of 2cm and a diameter of 50μm and place it in the bending line area of ​​the above double-sided board.

[0068] (3) Apply silver paste to the silver wires on the double-sided board using a dispensing process to fix and achieve the connection between the silver wires and the non-bending circuit layer, and then bake and cure.

[0069] (4) Single-sided etched circuits to form an outer non-bent circuit layer. The line width / spacing of the circuits in this circuit layer is 100μm / 100μm. The outer bent circuit area is also designed to be 2cm long. The conductive layer of the outer bent circuit area is etched away, leaving no circuits.

[0070] (5) Take a silver wire with a length of 2cm and a diameter of 50μm and place it in the outer layer of the single-sided board bending circuit area.

[0071] (6) Apply silver paste to the silver wires on the double-sided board using a dispensing process to fix and achieve a connection between the silver wires and the outer non-bent circuit layer.

[0072] (5) Apply adhesive to the single-sided and double-sided boards after the circuit fabrication is completed.

[0073] (6) Double-sided protective film is laminated to obtain sample 2.

[0074] Comparison examples: (1) The single-sided board and the double-sided board are etched by conventional etching process respectively. The circuit layer is formed in the entire circuit area of ​​the single-sided board and the entire circuit area of ​​the double-sided board. The line width / line spacing of the circuit of the single-sided board and the double-sided board is 100μm / 100μm.

[0075] (2) Apply adhesive to single-sided and double-sided boards after etching the circuit lines.

[0076] (3) Double-sided protective film was laminated to obtain the comparison sample.

[0077] After completing the two fabrication examples and the comparison example according to the above steps, the bending resistance performance was compared. Specifically, 5 pieces each of the implementation sample 1, implementation sample 2, and comparison sample were taken and subjected to dynamic bending tests on a dynamic bending tester. The bending radius was R=0.6mm, the frequency was 60 times / min, and the bending was performed at 90 degrees on both sides. The test was stopped when the resistance change was >10%, and the number of bends was recorded. The specific comparison results are shown in Table 1 below.

[0078] Table 1 Comparison of bending counts for each example As can be seen from Table 1 above, the flexible circuit board manufactured by the method of this embodiment has a higher bending resistance and a longer bending performance.

[0079] Example 2 This embodiment provides a bend-resistant FPC with segmented metal circuitry, which is manufactured using the method described in Embodiment 1.

[0080] The FPC manufactured in this embodiment, based on segmented metal circuitry, has superior bending resistance, and the overall bending resistance of the FPC is effectively improved.

[0081] The manufacturing method used in this embodiment is the same as the method described in Embodiment 1. Therefore, for details not covered in this embodiment, please refer to Embodiment 1 and... Figures 1-7B The specific description will not be repeated in this embodiment.

[0082] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for manufacturing a bend-resistant FPC with segmented metallic circuitry, characterized in that, The method includes: A circuit board substrate is provided; wherein, the circuit board substrate has a pre-defined bending circuit area and a non-bending circuit area; The circuit board substrate is fabricated to form a non-bending circuit layer on the non-bending circuit area of ​​the circuit board substrate, and the bending circuit area is free of circuits, thus obtaining a semi-finished circuit board. A segmented metal material is provided, and based on the bent circuit area, a segmented metal circuit layer electrically connected to the non-bent circuit layer is formed on the circuit board semi-finished product to obtain a flexible circuit board.

2. The manufacturing method according to claim 1, characterized in that, The block metal material includes any one of copper, silver, and gold.

3. The manufacturing method according to claim 1, characterized in that, The block metal material is specifically a liquid metal slurry; Provide a segmented metal material, and based on the bent circuit area, form a segmented metal circuit layer on the circuit board semi-finished product that is electrically connected to the non-bent circuit layer, including: The metal paste is provided and screen-printed onto the bent circuit area of ​​the circuit board semi-finished product to form a segmented metal coating that is electrically connected to the non-bent circuit layer. The segment metal coating on the circuit board semi-finished product is baked and cured to obtain the segment metal circuit layer.

4. The manufacturing method according to claim 3, characterized in that, Before forming a segmented metal circuit layer on the circuit board semi-finished product, the method further includes: Based on the bent line area, a screen printing template for printing the metal paste is made.

5. The manufacturing method according to claim 1, characterized in that, The block metal material specifically includes liquid metal slurry and solid metal wire; Provide a segmented metal material, and based on the bent circuit area, form a segmented metal circuit layer on the circuit board semi-finished product that is electrically connected to the non-bent circuit layer, including: Provide the metal wire with a preset wire diameter, fix the metal wire to the bent circuit area of ​​the circuit board semi-finished product, so that the metal wire is electrically connected to the non-bent circuit layer; A metal paste is provided, and the metal paste is applied to the metal wire in the bent circuit area by a dot coating method to form a segmented metal coating. The segment metal coating on the circuit board semi-finished product is baked and cured to obtain the segment metal circuit layer.

6. The manufacturing method according to claim 5, characterized in that, The preset wire diameter ranges from 10 to 50 μm.

7. The manufacturing method according to claim 3 or 5, characterized in that, During the baking and curing process of the block metal coating, the temperature range is 130~180℃ and the time range is 30~90min.

8. The manufacturing method according to claim 1, characterized in that, The circuit board substrate is fabricated by forming a non-bending circuit layer on the non-bending circuit area of ​​the circuit board substrate, thereby eliminating the circuit in the bending circuit area, to obtain a semi-finished circuit board, comprising: The non-bending circuit area and the bending circuit area of ​​the circuit board substrate are simultaneously etched to form a non-bending circuit layer on the non-bending circuit area of ​​the circuit board substrate, and to make the bending circuit area free of circuits, thereby obtaining the circuit board semi-finished product.

9. The manufacturing method according to claim 1, characterized in that, After forming a segmented metal circuit layer on the circuit board semi-finished product, the method further includes: An outer circuit substrate is provided; wherein, the outer circuit substrate has an outer bending circuit area; Using the same method as forming the segmented metal circuit layer on the circuit board semi-finished product, an outer layer segmented metal circuit is formed on the outer layer bent circuit area of ​​the outer layer circuit substrate to obtain an outer layer circuit board. Based on the bent circuit area and the outer bent circuit area, the outer circuit board and the circuit board semi-finished product having the segmented metal circuit layer are glued and pressed together.

10. The manufacturing method according to claim 9, characterized in that, The circuit board substrate is any one of single-sided, double-sided, and multilayer boards, and / or the outer circuit substrate is a single-sided or double-sided board.

11. A bend-resistant FPC with segmented metallic circuitry, characterized in that, It is manufactured using the manufacturing method described in any one of claims 1 to 10.

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