A tear-resistant FPC flexible printed circuit board

Abstract

The utility model relates to FPC flexible printed circuit board technical field, especially relates to a kind of tear-resistant FPC flexible printed circuit board, including FPC flexible printed circuit board main body, the FPC flexible printed circuit board main body front end upper portion is equipped with front and rear through fixed slot, the FPC flexible printed circuit board main body lower end is fixedly connected with two tear-resistant components, two the tear-resistant components lower end are all fixedly connected with connector.The utility model relates to a kind of tear-resistant FPC flexible printed circuit board, by the PI layer of bending area is replaced for high flexibility green oil covering layer, collocates grid copper pavement layer, effectively reduces the rigidity of bending area, disperses stress, avoids the crack and tear caused by stress concentration, edge reinforcement reinforcement layer strengthens the edge of bending area, prevent warping, tear, FPC flexible printed circuit board main body strengthens the ability of circuit board resistance external force pulling from overall, substantially improve the tear-resistant performance of FPC, satisfy complex use scene demand.

Description

Technical Field

[0001] This utility model relates to the field of FPC flexible printed circuit board technology, and in particular to a tear-resistant FPC flexible printed circuit board. Background Technology

[0002] Flexible printed circuit boards (FPCs) are widely used in consumer electronics, medical devices, aerospace, and other fields due to their thinness, flexibility, and high wiring density. In practical applications, especially in foldable devices and precision instruments, FPCs often need to be bent frequently to adapt to complex spatial layouts. However, traditional FPC bending areas generally use a PI (polyimide) layer to cover the circuitry, combined with a solid copper ground plane. Although PI material has good insulation and high-temperature resistance, it is brittle and lacks flexibility, making it prone to cracking during repeated bending. The solid copper ground plane further increases the rigidity of this area, making stress concentration more pronounced during bending. During product assembly, even slight external force can cause tearing in the FPC bending area, which not only seriously affects the electrical performance of the circuit board but also easily leads to the failure of the entire device. This greatly limits the application of FPCs in scenarios with high reliability and high flexibility requirements. Therefore, we have introduced a tear-resistant FPC flexible printed circuit board. Utility Model Content

[0003] The main objective of this invention is to provide a tear-resistant FPC flexible printed circuit board, which can effectively solve the problems in the background art.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] A tear-resistant FPC flexible printed circuit board includes an FPC flexible printed circuit board body. A fixing groove with front and rear through is opened at the upper front end of the FPC flexible printed circuit board body. Two tear-resistant components are fixedly connected to the lower end of the FPC flexible printed circuit board body, and connectors are fixedly connected to the lower ends of the two tear-resistant components.

[0006] Preferably, the tear-resistant component includes a bending area circuit layer, the front end of the bending area circuit layer is wrapped with an insulating substrate layer, the front end of the insulating substrate layer is provided with a grid copper ground layer, the surface of the grid copper ground layer is coated with a highly flexible green oil covering layer, and the four sides of the bending area circuit layer, the four sides of the insulating substrate layer and the four sides of the grid copper ground layer are jointly wrapped with an edge reinforcement layer.

[0007] By adopting the above technical solution: the grid copper ground layer is made on the insulating substrate layer through etching process. While ensuring electrical performance, the grid copper ground layer minimizes rigidity. When bending, the grid copper ground layer can disperse stress and reduce local stress concentration. The grid gaps reserve space for material deformation, making bending smoother and reducing the risk of tearing. At the same time, it meets the requirements of electrical connection and shielding of the circuit.

[0008] The high-flexibility green solder mask coating uses liquid photosensitive solder mask with high flexibility and high adhesion. After curing, it has good elasticity and can withstand multiple bends without cracking. It replaces the traditional PI layer to cover the circuit and provides insulation protection for the circuit. With its soft properties, it can deform synchronously with the circuit when bent, effectively relieving stress concentration and improving the flexibility and tear resistance of the bending area.

[0009] The edge reinforcement layer is made of epoxy resin adhesive, which has high hardness and toughness after curing. Epoxy resin adhesive is applied to the perimeter of the circuit layer, the insulating substrate layer, and the grid copper ground layer in the bending area through screen printing. After curing, it forms an edge reinforcement layer, which enhances the edge strength and toughness of the bending area, prevents the edges from warping or tearing during bending and assembly, and improves the overall structural stability.

[0010] Preferably, the circuit layer in the bending area is located at the lower end of the FPC flexible printed circuit board body.

[0011] Preferably, the grid copper ground layer is electrically connected to the circuit layer in the bending area, and the perimeter of the grid copper ground layer is connected to the copper foil layers in other areas of the circuit board.

[0012] By adopting the above technical solution, the grid copper ground layer is electrically connected to the circuit layer in the bending area, which can achieve good electrical conductivity, ensure smooth current transmission throughout the circuit system, provide a stable reference potential and shielding function for the circuit, reduce the impact of electromagnetic interference on signal transmission, and at the same time, it is connected to the copper foil layers of other areas of the circuit board to build a complete electrical network, ensuring the consistency and stability of the electrical performance of the entire FPC circuit board and meeting the working requirements of complex circuit systems.

[0013] Preferably, the FPC flexible printed circuit board body includes a high-toughness insulating substrate layer, a composite conductive circuit layer is disposed at the front end of the high-toughness insulating substrate layer, an enhanced cover film layer is wrapped around the front end of the composite conductive circuit layer, and a surface wear-resistant and tear-resistant layer is coated on the front end of the enhanced cover film layer.

[0014] By adopting the above technical solution: the high-toughness insulating substrate layer uses thermoplastic polyimide (TPI) instead of traditional polyimide. TPI has the electrical insulation and high temperature resistance properties of PI, while also having higher flexibility and tear resistance. Nanoscale carbon fiber reinforcement material is added to further improve the overall mechanical properties, provide stable support for the circuit board, withstand external mechanical stress, ensure stable adhesion of the conductive line layer, and during bending, its high toughness and the reinforcement material work together to disperse stress and prevent cracks from forming.

[0015] The reinforced cover film is made of polyimide film, with a layer of biaxially oriented polyester (BOPET) fiber mesh laminated in it to protect the conductive lines from external environmental corrosion. The (BOPET) fiber mesh is interspersed in the polyimide film to form a mesh support structure, which effectively disperses external forces, prevents tear propagation, and greatly improves the tear resistance of the circuit board.

[0016] The surface wear-resistant and tear-resistant layer uses a nano-sized silica-reinforced fluororubber coating to form a wear-resistant and scratch-resistant surface protective layer, protecting the circuit board from external friction damage. The nano-silica-reinforced fluororubber has high tear resistance and assists other structures in resisting tearing when the circuit board is subjected to external force.

[0017] Preferably, the composite conductive circuit layer consists of an inner high-purity copper foil, a middle flexible conductive film, and an outer graphene nanosheet coating. The copper foil is etched to form the circuit, the flexible conductive film fills the surface of the copper foil circuit, and the graphene nanosheets are chemically deposited onto the surface of the conductive film.

[0018] By adopting the above technical solution: the inner high-purity copper foil is responsible for signal transmission and power conduction, the middle flexible conductive film allows the copper foil lines to move slightly when the circuit board is bent, relieves stress concentration, and at the same time enhances the bonding force between the inner high-purity copper foil and the outer graphene nanosheet coating. The outer graphene nanosheet coating improves the conductivity and wear resistance of the lines, further disperses stress, and protects the copper foil lines from being torn.

[0019] Preferably, the reinforced cover film is applied to the composite conductive circuit layer by hot pressing and adhesive, and the edge of the reinforced cover film is aligned with the edge of the high-toughness insulating substrate layer and sealed with adhesive.

[0020] By adopting the above technical solution: a tightly fitted and sealed structure, external factors are effectively prevented from interfering with the electrical performance of the circuit, moisture and impurities are avoided from affecting the conductivity and insulation of the circuit, ensuring stable and reliable signal transmission and power conduction, and improving the stability and reliability of FPC in various complex environments.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. In this utility model, by replacing the PI layer in the bending area with a highly flexible green oil covering layer, and combining it with a grid copper base layer, the rigidity of the bending area is effectively reduced, stress is dispersed, and cracks and tears caused by stress concentration are avoided. The edge reinforcement layer strengthens the edge of the bending area to prevent warping and tearing.

[0023] 2. In this utility model, the high-toughness insulating substrate layer, the reinforced cover film layer, and the surface wear-resistant and tear-resistant layer of the FPC flexible printed circuit board body enhance the circuit board's ability to resist external pulling force as a whole, greatly improve the tear resistance of the FPC, and meet the needs of complex usage scenarios. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of a tear-resistant FPC flexible printed circuit board according to this utility model.

[0025] Figure 2 This is a schematic diagram of the main body of the FPC flexible printed circuit board of the present invention, which is a tear-resistant FPC flexible printed circuit board.

[0026] Figure 3 This utility model relates to a tear-resistant flexible printed circuit board (FPC). Figure 2 Enlarged view of the structure at point A in the image;

[0027] Figure 4 This is an exploded view of the main body of the FPC flexible printed circuit board, which is a tear-resistant FPC flexible printed circuit board according to this utility model.

[0028] Figure 5 This is a schematic diagram of the structure of the tear-resistant component of a tear-resistant FPC flexible printed circuit board according to the present invention;

[0029] Figure 6 This is an exploded view of the structure of the tear-resistant component of a tear-resistant FPC flexible printed circuit board according to this utility model.

[0030] In the diagram: 1. FPC flexible printed circuit board body; 2. Fixing groove; 3. Tear-resistant component; 4. Connector; 11. High-toughness insulating substrate layer; 12. Composite conductive circuit layer; 13. Reinforced cover film layer; 14. Surface abrasion-resistant and tear-resistant layer; 31. Circuit layer in bending area; 32. Insulating substrate layer; 33. Mesh copper ground layer; 34. High-flexibility green oil cover layer; 35. Edge reinforcement layer. Detailed Implementation

[0031] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0032] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," and "connected," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0034] Please see Figure 1-6 This utility model provides a technical solution:

[0035] A tear-resistant FPC flexible printed circuit board includes an FPC flexible printed circuit board body 1. A fixing groove 2 with front and rear through is opened at the upper front end of the FPC flexible printed circuit board body 1. Two tear-resistant components 3 are fixedly connected to the lower end of the FPC flexible printed circuit board body 1. Each of the two tear-resistant components 3 has a connector 4 fixedly connected to its lower end.

[0036] In this embodiment, the tear-resistant component 3 includes a bending area circuit layer 31, with an insulating substrate layer 32 wrapped around the front end of the bending area circuit layer 31. A grid copper ground layer 33 is disposed at the front end of the insulating substrate layer 32. The surface of the grid copper ground layer 33 is coated with a high-flexibility green oil cover layer 34. An edge reinforcement layer 35 is wrapped around the bending area circuit layer 31, the insulating substrate layer 32, and the grid copper ground layer 33. The bending area circuit layer 31 is disposed at the lower end of the FPC flexible printed circuit board body 1. The grid copper ground layer 33 is electrically connected to the bending area circuit layer 31, and the periphery of the grid copper ground layer 33 is connected to the copper foil layers of other areas of the circuit board. The FPC flexible printed circuit board body 1 includes a high-flexibility insulating substrate layer 32. The high-toughness insulating substrate layer 11 has a composite conductive circuit layer 12 at its front end. The front end of the composite conductive circuit layer 12 is wrapped with an enhanced cover film layer 13, and the front end of the enhanced cover film layer 13 is coated with a surface wear-resistant and tear-resistant layer 14. The composite conductive circuit layer 12 is composed of an inner high-purity copper foil, a middle flexible conductive film, and an outer graphene nanosheet coating. The copper foil is etched to form circuits, the flexible conductive film fills the surface of the copper foil circuits, and the graphene nanosheets are chemically deposited on the surface of the conductive film. The enhanced cover film layer 13 is covered on the composite conductive circuit layer 12 by hot pressing and adhesive, and the edge of the enhanced cover film layer 13 is aligned with the edge of the high-toughness insulating substrate layer 11 and sealed with adhesive.

[0037] It should be noted that this utility model is a tear-resistant FPC flexible printed circuit board. During use, the FPC flexible printed circuit board body 1 serves as the core carrier. The fixing groove 2 at the upper front end can be used to fix it with external components, ensuring stable installation of the circuit board in the equipment. The tear-resistant component 3 and connector 4 at the lower end respectively undertake the functions of tear resistance and circuit connection, enabling the circuit board to adapt to complex physical environments and achieve stable electrical connections. The circuit layer 31 in the bending area is the key path for circuit signal transmission, responsible for achieving electrical connections in specific areas. It is electrically connected to the grid copper ground layer 33 to ensure smooth current transmission. At the same time, under the protection of the insulating substrate layer 32 and the high-flexibility green oil covering layer 34, it avoids external damage. To prevent interference and physical damage and ensure signal transmission stability, the insulating substrate layer 32 provides a stable support foundation for the circuit layer 31 and the grid copper ground layer 33 in the bending area, ensuring the relative position stability of each layer. Simultaneously, its insulating properties prevent short circuits between different conductive layers, ensuring safe circuit operation and, to a certain extent, assisting in stress dispersion. The grid copper ground layer 33, while ensuring electrical performance, minimizes rigidity through its grid structure. When the circuit board bends, the grid structure disperses stress throughout the area, reducing localized stress concentration. The grid gaps provide space for material deformation, making the bending process smoother and effectively reducing the risk of tearing. It also meets the electrical connectivity and shielding requirements of the circuit, ensuring signal transmission stability. The stable and highly flexible green solder mask layer 34 uses a liquid photosensitive solder resist with high flexibility and adhesion. After curing, it has good elasticity and can withstand multiple bends without cracking. It replaces the traditional PI layer to cover the circuit, providing insulation protection for the circuit. When the circuit board is bent, it deforms synchronously with the circuit, effectively relieving stress concentration and significantly improving the flexibility and tear resistance of the bending area. The edge reinforcement layer 35 uses epoxy resin material, which is applied to the periphery of the circuit layer 31, the insulating substrate layer 32, and the grid copper ground layer 33 in the bending area through a screen printing process. After curing, it forms a high-hardness and high-toughness edge reinforcement layer. Its function is to enhance the strength and toughness of the edge of the bending area, prevent the edge from warping and tearing during bending and assembly, and improve the overall structure. To ensure structural stability, the high-toughness insulating substrate layer 11 is made of thermoplastic polyimide (TPI) with added nano-scale carbon fiber reinforcement. It combines the electrical insulation and high-temperature resistance properties of traditional polyimide with higher flexibility and tear resistance, providing stable support for the entire circuit board and withstanding external mechanical stress. This ensures stable adhesion of the composite conductive circuit layer 12. During circuit board bending, its high toughness and the synergistic effect of the reinforcement material disperse stress and prevent cracking. The inner high-purity copper foil layer is responsible for signal transmission and power conduction, forming the basis for circuit functionality. The intermediate flexible conductive film layer allows for slight displacement of the copper foil lines during circuit board bending, alleviating stress concentration and enhancing the adhesion between the copper foil and the outer graphene nanosheet coating.The outer graphene nanosheet coating enhances the conductivity and wear resistance of the circuit, further disperses stress, and protects the copper foil circuit from tearing. These three elements work together to ensure stable circuit operation under various conditions. The reinforced cover layer 13 uses a polyimide film composite biaxially oriented polyester (BOPET) fiber mesh. The polyimide film protects the conductive circuit from external environmental corrosion, while the BOPET fiber mesh interwoven within forms a mesh support structure. When the circuit board is subjected to external force, it effectively disperses the force, prevents tear propagation, and significantly improves the circuit board's tear resistance. The surface wear-resistant and tear-resistant layer 14 uses a nano-scale silica-reinforced fluororubber coating, forming a wear-resistant and scratch-resistant surface protective layer that protects the circuit board from external friction damage. The nano-silica-reinforced fluororubber has high tear resistance and, when the circuit board is subjected to external pulling force, assists other structures in resisting tearing, extending the circuit board's service life.

[0038] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A tear-resistant FPC flexible printed circuit board, comprising an FPC flexible printed circuit board body (1), characterized in that: The upper front end of the FPC flexible printed circuit board body (1) is provided with a through-hole (2), and two anti-tear components (3) are fixedly connected to the lower end of the FPC flexible printed circuit board body (1). Both anti-tear components (3) are fixedly connected to a connector (4) at the lower end. The tear-resistant component (3) includes a bending area circuit layer (31), the front end of which is wrapped with an insulating substrate layer (32), the front end of which is provided with a grid copper ground layer (33), the surface of which is coated with a highly flexible green oil covering layer (34), and the edges of the bending area circuit layer (31), the insulating substrate layer (32), and the grid copper ground layer (33) are all wrapped with an edge reinforcement layer (35).

2. The tear-resistant FPC flexible printed circuit board according to claim 1, characterized in that: The bending area circuit layer (31) is located at the lower end of the FPC flexible printed circuit board body (1).

3. The tear-resistant FPC flexible printed circuit board according to claim 1, characterized in that: The grid copper ground layer (33) is electrically connected to the circuit layer (31) in the bending area, and the grid copper ground layer (33) is connected to the copper foil layer in other areas of the circuit board around its perimeter.

4. The tear-resistant FPC flexible printed circuit board according to claim 1, characterized in that: The FPC flexible printed circuit board body (1) includes a high-toughness insulating substrate layer (11), a composite conductive line layer (12) is provided at the front end of the high-toughness insulating substrate layer (11), an enhanced cover film layer (13) is wrapped around the front end of the composite conductive line layer (12), and a surface wear-resistant and tear-resistant layer (14) is coated at the front end of the enhanced cover film layer (13).

5. The tear-resistant FPC flexible printed circuit board according to claim 4, characterized in that: The composite conductive circuit layer (12) consists of an inner high-purity copper foil, a middle flexible conductive film, and an outer graphene nanosheet coating. The copper foil is etched to form a circuit, the flexible conductive film fills the surface of the copper foil circuit, and the graphene nanosheets are chemically deposited on the surface of the conductive film.

6. The tear-resistant FPC flexible printed circuit board according to claim 4, characterized in that: The enhanced cover film (13) is covered on the composite conductive circuit layer (12) by hot pressing and adhesive, and the edge of the enhanced cover film (13) is aligned with the edge of the high toughness insulating substrate layer (11) and sealed by adhesive.

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