Flexible printed circuit (FPC) structure capable of being bent at high strength

Abstract

The utility model relates to the technical field of flexible circuit boards, and discloses an FPC structure capable of being bent at high strength, which comprises a connecting PI film, and a first copper foil substrate and a second copper foil substrate are respectively adhered to two sides of the connecting PI film. Reinforcing layers are adhered to one side, opposite to the connecting PI film, of the first copper foil substrate and one side, opposite to the connecting PI film, of the second copper foil substrate, and open slots are formed in the opposite sides of the first copper foil substrate and the second copper foil substrate; through the cooperation of the PI film, the first copper foil substrate, the second copper foil substrate, the slot and the reinforcing layer, the reinforcing layer is used for improving the overall strength of the FPC, the first copper foil substrate and the second copper foil substrate both have high bending performance, so that the bending performance of the FPC is improved, meanwhile, the slot is used for reducing the stress increase in the bending time of the FPC, and the bending performance of the FPC is improved. The bending stress can be released conveniently, so that the bending part of the FPC is prevented from being torn, and the service life of the FPC is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of flexible printed circuit boards, and particularly relates to an FPC structure capable of being bent with high strength. Background Technique

[0002] A flexible printed circuit board is a highly reliable and extremely flexible printed circuit board made of polyimide or polyester film as the base material. Compared with traditional PCB boards, flexible printed circuit boards have the following characteristics: short assembly time, all circuits are configured, eliminating the need for redundant wire connection work, smaller volume than rigid PCB boards, effectively reducing the product volume and increasing the convenience of carrying, lighter weight than rigid PCB boards, reducing the weight of the final product, thinner thickness than rigid PCB boards, improving softness, enhancing three-dimensional assembly in a limited space, being bendable and curlable, and having wide adaptability;

[0003] Although existing flexible printed circuit boards can be bent at a certain angle, during the bending process, existing flexible printed circuit boards may be deformed and broken due to excessive bending angle, and the overall strength of the flexible printed circuit board is insufficient. As a result, the flexible printed circuit board is prone to scrapping during installation and disassembly, reducing the overall service life of the flexible printed circuit board. Therefore, we need to propose an FPC structure capable of being bent with high strength. Content of the Utility Model

[0004] The purpose of the utility model is to provide an FPC structure capable of being bent with high strength. By adding a reinforcing layer and a mesh anti-cracking layer to the flexible printed circuit board, the overall strength of the flexible printed circuit board is improved, avoiding bending and tearing of the flexible printed circuit board during disassembly and installation, improving the flexibility and bendability of the flexible printed circuit board, and further improving the service life of the flexible printed circuit board, so as to solve the problems raised in the above background technique.

[0005] To achieve the above purpose, the utility model provides the following technical solution: an FPC structure capable of being bent with high strength, including a connecting PI film, a first copper foil substrate and a second copper foil substrate are respectively bonded on both sides of the connecting PI film, a reinforcing layer is bonded on the side of the first copper foil substrate opposite to the connecting PI film and the side of the second copper foil substrate opposite to the connecting PI film, slots are opened on the side of the first copper foil substrate opposite to the second copper foil substrate, a hollow part communicating with the slots is opened on one side of the reinforcing layer, and corner guards are arranged at the four corners of the first copper foil substrate and the four corners of the second copper foil substrate.

[0006] Preferably, the first copper foil substrate includes a first copper foil layer, a first outer adhesive layer and a first protective PI film, the first outer adhesive layer is bonded on one side of the first copper foil layer, and the first protective PI film is bonded on one side of the first outer adhesive layer.

[0007] Preferably, a first inner adhesive layer is bonded to the opposite side of the first copper foil layer and the first outer adhesive layer, and the first inner adhesive layer is bonded to one side of the connecting PI film.

[0008] Preferably, the second copper foil substrate includes a second copper foil layer, a second outer adhesive layer, and a second protective PI film. The second outer adhesive layer is bonded to one side of the second copper foil layer, and the second protective PI film is bonded to one side of the second outer adhesive layer.

[0009] Preferably, a first inner adhesive layer is bonded to the side of the second copper foil layer opposite to the second outer adhesive layer, and the first inner adhesive layer is bonded to the other side of the connecting PI film.

[0010] Preferably, the first copper foil layer is a mesh-shaped rolled copper foil, the second copper foil layer is a planar rolled copper foil, and the right-angle sides of the corner guard sleeve are rounded.

[0011] Preferably, the first inner adhesive layer, the second inner adhesive layer, the first outer adhesive layer, and the second outer adhesive layer are all epoxy resin thermosetting adhesives, and the first inner adhesive layer, the second inner adhesive layer, the first outer adhesive layer, and the second outer adhesive layer have the same thickness.

[0012] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0013] The present utility model mainly improves the overall strength of the FPC by the cooperation among the connecting PI film, the first copper foil substrate, the second copper foil substrate, the slotted groove, and the reinforcing layer. Both the first copper foil substrate and the second copper foil substrate have high bending performance, thereby improving the bending performance of the FPC. At the same time, the slotted groove is used to reduce the stress increase during the bending time of the FPC, facilitating the release of the bending stress, thereby avoiding tearing of the bent part of the FPC and improving the service life of the FPC. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a three-dimensional structural schematic diagram of the present utility model;

[0015] Figure 2 is an exploded structural schematic diagram of the present utility model;

[0016] Figure 3 is a sectional structural schematic diagram of the present utility model.

[0017] In the figure: 1, connecting PI film; 2, first copper foil substrate; 21, first copper foil layer; 22, first inner adhesive layer; 23, first outer adhesive layer; 24, first protective PI film; 3, second copper foil substrate; 31, second copper foil layer; 32, second inner adhesive layer; 33, second outer adhesive layer; 34, second protective PI film; 4, slotted groove; 5, reinforcing layer; 6, corner guard sleeve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] Please refer to Figures 1-3 , the present invention provides a technical solution: an FPC structure that can be bent with high strength, including a connecting PI film 1. First copper foil substrates 2 and second copper foil substrates 3 are adhesively bonded to both sides of the connecting PI film 1 respectively. Reinforcing layers 5 are adhesively bonded to the sides of the first copper foil substrate 2 opposite to the connecting PI film 1 and the sides of the second copper foil substrate 3 opposite to the connecting PI film 1. Grooves 4 are provided on the sides of the first copper foil substrate 2 opposite to the second copper foil substrate 3. Hollow parts communicating with the grooves 4 are provided on one side of the reinforcing layer 5. Corner protectors 6 are provided at the four corners of the first copper foil substrate 2 and the four corners of the second copper foil substrate 3.

[0020] The first copper foil substrate 2 includes a first copper foil layer 21, a first outer adhesive layer 23, and a first protective PI film 24. The first outer adhesive layer 23 is adhesively bonded to one side of the first copper foil layer 21, and the first protective PI film 24 is adhesively bonded to one side of the first outer adhesive layer 23. By using the mesh structure of the first copper foil layer 21, the stress during bending of the FPC is reduced, thereby improving the bending performance of the FPC.

[0021] A first inner adhesive layer 22 is adhesively bonded to the opposite side of the first copper foil layer 21 and the first outer adhesive layer 23. The first inner adhesive layer 22 is adhesively bonded to one side of the connecting PI film 1. The connecting PI film 1 and the first copper foil layer 21 are connected through the first inner adhesive layer 22, so that when the first copper foil layer 21 is bent, the first protective PI film 24 and the connecting PI film 1 are bent synchronously, and the bending angle is increased under the action of the groove 4, avoiding tearing due to excessive bending angle.

[0022] The second copper foil substrate 3 includes a second copper foil layer 31, a second outer adhesive layer 33, and a second protective PI film 34. The second outer adhesive layer 33 is adhesively bonded to one side of the second copper foil layer 31, and the second protective PI film 34 is adhesively bonded to one side of the second outer adhesive layer 33. The second protective PI film 34 on the second copper foil layer 31 can be bent in cooperation with the second copper foil layer 31 when the FPC is bent to the other side, thereby ensuring the service life of the FPC and avoiding bending and tearing.

[0023] On one side of the second copper foil layer 31 opposite to the second outer adhesive layer 33, a first inner adhesive layer 22 is bonded. The first inner adhesive layer 22 is bonded to the other side of the connecting PI film 1. By means of the connecting PI film 1, the connection stability between the first copper foil substrate 2 and the second copper foil substrate 3 is improved, thereby increasing the service life of the FPC. By utilizing the double anti-bending properties of the first copper foil layer 21 and the second copper foil layer 31, the service life of the FPC is further increased.

[0024] The first copper foil layer 21 is a mesh-shaped rolled copper foil, and the second copper foil layer 31 is a planar rolled copper foil. The right-angle sides of the corner guard 6 are rounded. The rolled copper foil has high bendability, thereby improving the bendability of the FPC. Moreover, the corners of the FPC protected by the corner guard 6 are all rounded, which can better withstand stress and avoid stress tearing. At the same time, the distance between the installation of electronic components on the FPC and the edge is greater than 0.5 mm, and the distance between the holes opened on the FPC is greater than 1 mm.

[0025] The first inner adhesive layer 22, the second inner adhesive layer 32, the first outer adhesive layer 23, and the second outer adhesive layer 33 are all epoxy resin thermosetting adhesives. The first inner adhesive layer 22, the second inner adhesive layer 32, the first outer adhesive layer 23, and the second outer adhesive layer 33 have the same thickness. Through the settings of the first inner adhesive layer 22, the second inner adhesive layer 32, the first outer adhesive layer 23, and the second outer adhesive layer 33, the first copper foil substrate 2 and the second copper foil substrate 3 are well connected together. At the same time, the PI film is the best-performing thin-film insulation material, with excellent high and low temperature resistance, electrical insulation, adhesiveness, radiation resistance, and chemical resistance, and can be used for a long time in the temperature range of -269°C to 280°C, and can reach a short-term high temperature of 400°C.

[0026] When bending the PFC, the first protective PI film 24, the second protective PI film 34, and the connecting PI film 1 can be bent along with the first copper foil layer 21 and the second copper foil layer 31. By utilizing the slots 4 on the first protective PI film 24 and the second protective PI film 34, the overall bending performance of the FPC is improved. At the same time, the mesh setting adopted by the first copper foil layer 21 enables the release of stress during bending, and the rolling technology adopted by the second copper foil layer 31 greatly improves the bending performance of the copper foil itself, thereby enhancing the bending resistance of the FPC.

[0027] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-strength bendable FPC structure, comprising a connecting PI film (1), characterized in that: The first copper foil substrate (2) and the second copper foil substrate (3) are respectively bonded to both sides of the connecting PI film (1); a reinforcing layer (5) is bonded to the side of the first copper foil substrate (2) opposite to the connecting PI film (1) and the side of the second copper foil substrate (3) opposite to the connecting PI film (1); a groove (4) is provided on the side of the first copper foil substrate (2) opposite to the second copper foil substrate (3); a hollow portion connected to the groove (4) is provided on one side of the reinforcing layer (5); and corner protectors (6) are provided at the four corners of the first copper foil substrate (2) and the four corners of the second copper foil substrate (3).

2. The high-strength bendable FPC structure according to claim 1, characterized in that: The first copper foil substrate (2) comprises a first copper foil layer (21), a first outer adhesive layer (23) and a first protective PI film (24), wherein the first outer adhesive layer (23) is bonded to one side of the first copper foil layer (21), and the first protective PI film (24) is bonded to one side of the first outer adhesive layer (23).

3. The high-strength bendable FPC structure according to claim 2, characterized in that: A first inner rubber layer (22) is bonded to the side of the first copper foil layer (21) opposite to the first outer rubber layer (23), and the first inner rubber layer (22) is bonded to the side connected to the PI film (1).

4. The high-strength bendable FPC structure according to claim 3, characterized in that: The second copper foil 3 substrate comprises a second copper foil layer (31), a second outer adhesive layer (33) and a second protective PI film (34); the second outer adhesive layer (33) is bonded to one side of the second copper foil layer (31), and the second protective PI film (34) is bonded to one side of the second outer adhesive layer (33).

5. The high-strength bendable FPC structure according to claim 4, characterized in that: A first inner rubber layer (22) is bonded to the side of the second copper foil layer (31) opposite to the second outer rubber layer (33), and the first inner rubber layer (22) is bonded to the other side of the connected PI film (1).

6. The high-strength bendable FPC structure according to claim 5, characterized in that: The first copper foil layer (21) is a grid-shaped rolled copper foil, the second copper foil layer (31) is a flat rolled copper foil, and the right-angled sides of the corner protector (6) are rounded.

7. The high-strength bendable FPC structure according to claim 6, characterized in that: The first inner rubber layer (22), the second inner rubber layer (32), the first outer rubber layer (23) and the second outer rubber layer (33) are all epoxy resin thermosetting adhesives, and the first inner rubber layer (22), the second inner rubber layer (32), the first outer rubber layer (23) and the second outer rubber layer (33) have the same thickness.

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