Softening FPC

Abstract

The utility model discloses a softened FPC (Flexible Printed Circuit), which is characterized in that copper foils are changed into grid copper, the FPC is softened by adopting larger spacing, increasing the interval and reducing the copper foils, and PI (Polyimide) covering the grid copper of the FPC is further removed, so that the hardness of the PI is reduced, the PI on the edge is reserved, the edge is reinforced, and easy tearing is prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of printed circuit boards, in particular to a softened FPC. Background Art

[0002] FPC (Flexible Printed Circuit) is a bendable printed circuit board made of polyimide or polyester film as the substrate. It has the advantages of high wiring density, light weight, thin thickness, good bendability, etc. It is an important component of electronic appliances, such as touch screens, TFT display modules, etc.

[0003] The Chinese utility model with publication number CN 207039988 U in the prior art discloses an FPC board, including a plug-in part and a binding part and a fixing part connected between the plug-in part and the binding part, the fixing part includes a first connection part connected to the plug-in part and a second connection part connected to the binding part, a PI reinforcing plate is attached to one side of the first connection part, and the second connection part includes a substrate, a copper foil outside the substrate, and a softening layer outside the copper foil, and the softening layer is made of a metal with a ductility greater than that of the copper foil. The embodiment of the utility model enhances the flexibility of the FPC by arranging a metal layer with a ductility greater than that of the second connection part at the bending part of the FPC, so as to facilitate bending when the binding part is fixed.

[0004] In this solution, the flexibility of the FPC is enhanced by adding a ductile metal layer. However, in order to enhance the shielding effect, the FPC is covered with an EMI film, which further increases the thickness of the FPC and makes it too hard. The stress is too high after bending, and it is prone to problems such as warping or poor connection. Utility Model Content

[0005] In order to solve the deficiencies of the above-mentioned prior art, the utility model provides a softened FPC, which softens the FPC by changing the grid copper grounding method, adopts a larger spacing, increases the interval, and reduces the copper foil, thereby reducing the bending stress and enhancing the flexibility of the FPC. The PI covering the grid copper of the FPC is further removed, thereby reducing the hardness of the PI. The PI on the edge is retained to strengthen the edge and prevent easy tearing. Finally, the PI on the grid copper that needs to be covered with an EMI film is removed and covered with the EMI film to complete a softened FPC with a shielding effect.

[0006] The technical problem to be solved by the utility model is achieved by the following technical solution: A softened FPC, comprising: an FPC, including a bending area and a non-bending area;

[0007] A bending area, wherein the bending area is connected to the non-bending area through a metal busbar, and a copper grid is provided on the bending area;

[0008] A first interface end, the first interface end being disposed at one end close to the bending area;

[0009] The grid copper and the metal wiring are arranged at intervals;

[0010] The second interface end is arranged at one end close to the non-bending area.

[0011] Furthermore, the FPC includes a base layer PI, an upper layer circuit, a lower layer circuit, an upper layer PI and a lower layer PI; the upper layer circuit and the lower layer circuit are respectively provided on the upper and lower surfaces of the base layer PI, and the upper layer PI and the lower layer PI are respectively provided on the side of the upper layer circuit and the lower layer circuit away from the base layer PI.

[0012] Furthermore, at least one of the upper circuit and the lower circuit includes the metal bus bar and the mesh copper.

[0013] Furthermore, an upper layer PI on the surface of the bending area is provided with a window area and a square-shaped PI surrounding the window area, and the mesh copper and the metal busbar are exposed in the window area.

[0014] Furthermore, the mesh copper wire width and spacing are set to be between 1:3 and 1:5.

[0015] Furthermore, the bending area also includes a grounding busbar, and the grounding busbar at the upper circuit is exposed from the window area provided in the upper PI.

[0016] Furthermore, two upper EMI layers and lower EMI layers that are staggered with each other are provided on the front and back sides of the bending area, and the upper EMI layer and the lower EMI layer cover the mesh copper and the metal busbar.

[0017] Furthermore, the staggered spacing d between the upper layer EMI and the lower layer EMI is 0.5-1.0 mm.

[0018] Furthermore, the upper layer EMI is overlapped with the grounding cable of the upper layer circuit not covered by the upper layer PI.

[0019] Furthermore, auxiliary wings protruding outward are arranged on both sides of the edge of the first interface end, and a plurality of gold fingers arranged in sequence are arranged on the edge of the first interface end.

[0020] The utility model has the following beneficial effects: a softened FPC, comprising: an FPC, comprising a bending area and a non-bending area; a bending area, the bending area is connected to the non-bending area through a metal bus bar, and the bending area is provided with a mesh copper; a first interface end, the first interface end is arranged at one end close to the bending area; the mesh copper and the metal bus bar are arranged at intervals; a second interface end, the second interface end is arranged at one end close to the non-bending area. The bending zone described in the present application is provided with a grid copper, and the grid copper can improve the hardness of the bending zone to avoid bending and tearing. Compared with the copper foil in the prior art, the copper covering area of ​​the grid copper 22 is smaller, and the rebound stress generated during bending is also smaller, which can soften the FPC locally, enhance the flexibility of the FPC, and reduce the bending stress; further, the upper layer PI of the FPC covering the grid copper is removed, thereby reducing the hardness of the PI layer, and the upper layer PI on the edge is retained to strengthen the edge and prevent easy tearing, and the upper layer PI on the grid copper that needs to be covered with the EMI film is removed, and the upper layer EMI is covered to complete a softened FPC with a shielding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the scheme in the present application, a brief introduction is given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A structural schematic diagram of a softened FPC provided by the utility model;

[0023] Figure 2 A schematic diagram of the softened FPC metal cable provided by the utility model;

[0024] Figure 3 A schematic diagram of the softened FPC EMI coating provided by the utility model;

[0025] Figure 4 A schematic diagram of the softened FPC stacking structure provided by the utility model;

[0026] Figure 5 This is a schematic diagram of the structure of the first interface end of the softened FPC provided by the utility model;

[0027] Figure 6 This is a schematic diagram of the stacking structure of the softened FPCEMI film provided by the utility model.

[0028] 1. FPC; 11. Non-bending area; 12. Bending area; 101. Base PI; 102. Upper circuit; 103. Lower circuit; 104. Upper PI; 105. Lower PI; 106. Upper EMI; 107. Lower EMI; 21. Metal cable; 22. Copper mesh; 23. Ground cable; 231. Round metal block; 3. First interface end; 31. Auxiliary wing; 32. Gold finger; 4. Second interface end. DETAILED DESCRIPTION

[0029] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments, examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0030] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix", "set" and the like should be understood in a broad sense, for example, it 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, or it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Example

[0033] like Figure 1 As shown, a softened FPC includes: FPC1, including a bending area 12 and a non-bending area 11;

[0034] A bending area 12, wherein the bending area 12 is connected to the non-bending area 11 through a metal busbar 21, and a copper mesh 22 is provided on the bending area 12;

[0035] A first interface end 3, wherein the first interface end 3 is disposed at one end close to the bending area 12;

[0036] The copper mesh 22 is spaced apart from the metal busbar 21;

[0037] The second interface end 4 is disposed at an end close to the non-bending area 11 .

[0038] In the present invention, when in use, the first interface end 3 and the second interface end 4 are respectively connected to two components. Due to the positional relationship between different components, the FPC needs to be bent to ensure the stability of the connection. The bending area 12 of the present application is provided with a mesh copper 22. The mesh copper 22 can increase the hardness of the bending area 12 to avoid bending and tearing. Compared with the copper foil in the prior art, the copper covering area of ​​the mesh copper 22 is smaller, and the rebound stress generated during bending is also smaller, which can soften the FPC locally, enhance the flexibility of the FPC, and reduce the bending stress. Furthermore, the upper layer PI 104 of the FPC covering the mesh copper 22 is removed, thereby reducing the hardness of the PI layer, and the upper layer PI 104 on the edge is retained to strengthen the edge and prevent easy tearing. The upper layer PI 104 on the mesh copper 22 that needs to be covered with an EMI film is removed, and the upper layer EMI106 is covered to complete a softened FPC with a shielding effect.

[0039] In this embodiment, Figure 4 As shown, the FPC1 includes a base layer PI101, an upper layer circuit 102, a lower layer circuit 103, an upper layer PI104 and a lower layer PI105; the upper layer circuit 102 and the lower layer circuit 103 are respectively provided on the upper and lower surfaces of the base layer PI101, and the upper layer PI104 and the lower layer PI105 are respectively provided on the surface of the upper layer circuit 102 and the lower layer circuit 103 away from the base layer PI101.

[0040] In another preferred implementation manner of this embodiment, at least one of the upper layer circuit 102 and the lower layer circuit 103 includes the metal bus wire 21 and the mesh copper 22 .

[0041] Preferably, the metal busbar 21 and the copper mesh 22 are formed by etching the same copper cladding layer of the upper circuit 102 or the lower circuit 103 .

[0042] It should be noted that etching is a commonly used metal processing technology used to perform fine pattern and structure processing on metal surfaces. In the electronics industry, etching technology is often used to make circuit boards and microelectronic devices. When making circuit boards, etching technology is often used to remove excess metal from the surface of copper foil to form the desired circuit pattern. Etching technology usually uses chemical solutions or electrochemical methods to expose the metal surface to a specific etchant to remove excess metal. When making circuit boards, etching technology can accurately remove metal from the surface of copper foil to form the desired circuit pattern and structure. Etching technology has the advantages of high precision, high efficiency and low cost. It can realize complex circuit patterns and microstructure processing, providing an important processing means for the manufacture of electronic devices.

[0043] Furthermore, the upper PI 104 on the surface of the bending area 12 is provided with a window area and a square-shaped PI surrounding the window area, and the window area exposes the mesh copper 22 and the metal busbar 21. The window can reduce the hardness of the PI layer and soften the FPC, while the square-shaped PI left outside the window area can ensure the strength of the bending area 12 to a certain extent and avoid bending and tearing.

[0044] Furthermore, the line width and spacing of the mesh copper 22 are set between 1:3 and 1:5. The mesh copper 22 is a hollow diamond mesh, which is composed of a plurality of copper wires interlaced with each other, wherein the mesh shape can also be circular, and the mesh shape is not limited in this embodiment. Through the above structure, the present application uses copper wires with larger spacing to form the mesh copper, increases the spacing, reduces the use of copper foil, and softens the FPC. Example

[0045] like Figure 2 As shown, the bending area 12 further includes a grounding bus line 23 . The grounding bus line 23 at the upper circuit 102 is exposed from the window area provided in the upper PI 201 . The grounding bus line 23 is separated by the metal bus line 21 .

[0046] Among them, the bending area 12 can be set as a double-layer circuit routing, and at least one layer of the bending area 12 is also provided with a metal wiring 21 and the grid copper 22. The grid copper 22 is spaced apart from the metal wiring 21. In this embodiment, the bending area 12 can be a single-layer metal wiring or a double-layer metal wiring.

[0047] Furthermore, if Figure 6 As shown, two upper layers EMI106 and lower layers EMI107 are disposed on the front and back sides of the bending area 12 , which are staggered with each other. The upper layer EMI106 and the lower layer EMI107 cover the mesh copper 22 and the metal busbar 21 .

[0048] Furthermore, the upper EMI 106 is overlapped with the grounding cable 23 of the upper circuit 102 that is not covered by the upper PI 104, thereby isolating the interference of electromagnetic waves on the FPC electronic components.

[0049] It should be noted that EMI is a commonly used electromagnetic shielding material, which is used to isolate electromagnetic wave interference from electronic equipment, lines and antennas. The main components of EMI are metal foil and plastic film. By covering the metal foil on the plastic film to form a thin film, and then applying it to the electronic equipment or lines that need to be shielded, it can isolate electromagnetic wave interference. The use of EMI can not only improve the anti-interference ability of electronic equipment and lines, but also improve the electromagnetic compatibility of equipment and reduce the level of electromagnetic radiation. EMI is widely used in electronic equipment, aerospace, military industry and other fields to ensure the normal operation and service life of equipment. The role of EMI is achieved by preventing the propagation of electromagnetic waves, so it has a high effect in electromagnetic isolation. At the same time, EMI is low in production cost and easy to process and install, so it is widely used in the protection and isolation of various electronic equipment and lines.

[0050] In this embodiment, Figure 3 As shown, the staggered spacing d of the upper EMI106 and the lower EMI107 is 0.5-1.0mm. The staggered arrangement of the upper EMI106 and the lower EMI107 can disperse the stress distribution on the FPC at the edge of the upper EMI106 and the lower EMI107. When the FPC is bent, the stress is dispersed, which can reduce the risk of copper layer fracture, thereby improving the yield and reducing costs. Example

[0051] like Figure 5 As shown, auxiliary wings 31 protruding outward are provided on both sides of the edge of the first interface end 3, and a plurality of gold fingers 32 arranged in sequence are provided on the edge of the first interface end 3. The auxiliary wings 31 can enhance the anti-twist strength of the side of the first interface end 3 of the FPC, and can better plug and unplug the gold fingers 32.

[0052] Among them, the gold finger 32 is a connection form on the electronic component connector, which is usually used to connect the circuit board to other circuit boards or plugs. It is a metal contact point protruding from the edge of the circuit board, usually made of metal materials such as copper, nickel or gold. The number and arrangement of the gold fingers 32 can be designed according to the needs of the circuit board. During the manufacturing process of the circuit board, the gold fingers 32 are usually formed by exposing the inner copper foil of the first interface end 3 through methods such as chemical corrosion or mechanical processing. After the manufacture of the gold fingers 32 is completed, it is also necessary to perform surface treatment on it, such as gold plating, to improve the conductivity and corrosion resistance of the connection. The advantages of the gold fingers 32 are high connection reliability, large contact area, and ability to withstand large currents and voltages. At the same time, the shape and arrangement of the gold fingers 32 can also be designed according to the needs of the circuit board, with high flexibility.

[0053] In this embodiment, the grounding cable 23 is disposed in the middle area of ​​the bending area 12, which can ensure a more stable grounding effect.

[0054] Furthermore, the ground bus wire 23 is separated from the metal bus wire 21 to avoid unnecessary interference.

[0055] In another preferred implementation of this embodiment, the width of the grounding cable 23 is 0.2-0.4 mm. In this embodiment, the width of the grounding cable 23 is increased and a round metal block 231 is provided on the grounding cable 23 in the gap portion of the cable to facilitate full contact with the upper EMI 106.

[0056] In another preferred implementation manner of this embodiment, the diameter of the circular metal block 231 is 0.8-1.2 mm.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the utility model rather than to limit them. Although the embodiments of the utility model are described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the embodiments of the utility model can still be modified or replaced by equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the scope of the technical solutions of the embodiments of the utility model.

Claims

1. A softened FPC, characterized in that: include: The FPC (1) includes a bending region (12) and a non-bending region (11); The bending area (12) is provided with a copper grid (22) and a metal busbar (21), the copper grid (22) and the metal busbar (21) are arranged at intervals, and the bending area (12) is connected to the non-bending area (11) via the metal busbar (21); A first interface end (3), the first interface end (3) being arranged at one end close to the bending area (12); A second interface end (4), the second interface end (4) being arranged at an end close to the non-bending area (11).

2. The softened FPC according to claim 1, characterized in that: The FPC (1) comprises a base layer PI (101), an upper layer circuit (102), a lower layer circuit (103), an upper layer PI (104) and a lower layer PI (105); the upper layer circuit (102) and the lower layer circuit (103) are respectively arranged on the upper and lower surfaces of the base layer PI (101); and the upper layer PI (104) and the lower layer PI (105) are respectively arranged on the surface of the upper layer circuit (102) and the lower layer circuit (103) away from the base layer PI (101).

3. The softened FPC according to claim 2, characterized in that: At least one of the upper layer circuit (102) and the lower layer circuit (103) comprises the metal bus wire (21) and the mesh copper (22).

4. The softened FPC according to claim 1, characterized in that: The upper layer PI (104) on the surface of the bending area (12) is provided with a window area and a square-shaped PI surrounding the window area, and the window area exposes the mesh copper (22) and the metal busbar (21).

5. The softened FPC according to claim 1, characterized in that: The line width and spacing of the grid copper (22) are set between 1:3 and 1:

5.

6. The softened FPC according to claim 2, characterized in that: The bending area (12) further comprises a grounding busbar (23), wherein the grounding busbar (23) at the upper circuit (102) is exposed from a window area provided in the upper PI (104); the grounding busbar (23) is separated by the metal busbar (21).

7. The softened FPC according to claim 6, characterized in that: Two upper EMI layers (106) and lower EMI layers (107) are arranged staggered on the front and back sides of the bending area (12); the upper EMI layer (106) and lower EMI layer (107) cover the mesh copper (22) and the metal busbar (21).

8. The softened FPC according to claim 7, characterized in that: The upper layer EMI (106) and the lower layer EMI (107) are staggered by a distance d of 0.5-1.0 mm.

9. The softened FPC according to claim 7, characterized in that: The upper layer EMI (106) is overlapped with the grounding cable (23) of the upper layer circuit (102) not covered by the upper layer PI (104).

10. The softened FPC according to claim 1, characterized in that: Auxiliary wings (31) protruding outwards are arranged on both sides of the edge of the first interface end (3), and a plurality of gold fingers (32) arranged in sequence are arranged on the edge of the first interface end (3).

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