Bending-resistant FPC

Abstract

The utility model discloses a bending-resistant FPC, which comprises an outer copper layer, a substrate and an inner copper layer which are tightly connected from top to bottom, the outer copper layer comprises at least two parallel first copper bars which are arranged at intervals, each first copper bar is transversely arranged, and the bottom surface of each first copper bar is tightly connected with the upper surface of the substrate; the inner side copper layer comprises a plurality of second copper bars which are arranged in parallel at intervals. The second copper bars are longitudinally arranged, and the upper surfaces of the second copper bars are tightly connected with the bottom face of the substrate. Through the structural form that the outer side copper layer is arranged to be in the transverse strip shape and the inner side copper layer is arranged to be in the longitudinal strip shape, the FPC of the structure is simple in structure, low in requirement for the machining technology, capable of resisting bending and capable of meeting the requirement for good impedance continuity.

Description

Technical Field

[0001] This utility model belongs to the field of FPC technology, specifically relating to a bend-resistant FPC. Background Technology

[0002] Currently, flexible printed circuits (FPCs) are widely used. The bending requirements for FPCs used in high-speed transmission lines for foldable screens are becoming increasingly stringent, with smaller bending radii, higher transmission speeds, and stricter impedance requirements. The main FPC structures are: mesh structure, coplanar waveguide structure, and air-gap structure. However, each of these has limitations and drawbacks: mesh structure FPCs have a limited number of bends; coplanar waveguide structure FPCs, while easy to bend, also have a limited number of bends, and require strict control of line width and spacing during design to control impedance, placing high demands on manufacturing processes; air-gap structure FPCs, while easy to bend, also have a limited number of bends. This structure involves creating an opening in the pure adhesive film between two layers in the bending area, creating air between them. During product bending and use, the impedance fluctuates within a certain range, resulting in instability. It is difficult for any of these three FPC structures to simultaneously achieve good impedance continuity and bendability.

[0003] Therefore, a new technology is needed to solve the problem that high-speed transmission lines of bent screens in existing technologies cannot achieve both good impedance continuity and good bendability. Utility Model Content

[0004] To address the aforementioned problems in the prior art, this invention provides a bend-resistant FPC that simultaneously satisfies both good impedance continuity and bendability.

[0005] The present invention adopts the following technical solution:

[0006] A bend-resistant FPC includes an outer copper layer, a substrate, and an inner copper layer that are tightly connected from top to bottom. The outer copper layer includes two parallel and spaced-apart first copper strips, each of which is laterally arranged and its bottom surface is tightly connected to the upper surface of the substrate. The inner copper layer includes a plurality of parallel and spaced-apart second copper strips, each of which is longitudinally arranged and its upper surface is tightly connected to the bottom surface of the substrate.

[0007] As a further improvement to the technical solution of this utility model, the length of each of the first copper strips is equal to the lateral width of the substrate.

[0008] As a further improvement to the technical solution of this utility model, the intervals between the second copper strips are uniform.

[0009] As a further improvement to the technical solution of this utility model, the length of each of the second copper strips is equal to the longitudinal length of the substrate.

[0010] As a further improvement to the technical solution of this utility model, the vertical side of the substrate includes a first side, a second side, a third side, and a fourth side connected end to end in sequence, and the outer sides of the two outermost second copper strips are respectively flush with the first side and the third side.

[0011] As a further improvement to the technical solution of this utility model, the center line of the distance between the two first copper strips coincides with the center line of the substrate.

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

[0013] The bend-resistant FPC of this solution sets the reference ground of the microstrip line as a horizontal strip structure, that is, the outer copper layer is a horizontal strip structure. This type of FPC is not only bend-resistant and simple in structure, but also has low requirements for processing technology, while also meeting good impedance continuity. Attached Figure Description

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0016] Figure 2 This is a schematic diagram of the overall structure of this utility model when bent;

[0017] Figure 3 This is a structural diagram of other conventional FPC products during bending;

[0018] Figure 4 yes Figure 3 A force diagram.

[0019] Figure label:

[0020] 1-Outer copper layer; 11-First copper strip;

[0021] 2-Substrate; 21-First side surface; 22-Second side surface;

[0022] 3-Inner copper layer; 31-Second copper strip. Detailed Implementation

[0023] The following will provide a clear and complete description of the concept, specific structure, and technical effects of this utility model in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, solution, and effects of this utility model. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The same reference numerals used throughout the drawings indicate the same or similar parts.

[0024] It should be noted that, unless otherwise specified, when a feature is referred to as "fixed" or "connected" to another feature, it can be directly fixed or connected to the other feature, or it can be indirectly fixed or connected to the other feature. Furthermore, the descriptions of "upper," "lower," "left," and "right" used in this utility model are only relative to the relative positional relationships of the various components of this utility model in the accompanying drawings.

[0025] Reference Figures 1 to 2 A bend-resistant FPC includes an outer copper layer 1, a substrate 2, and an inner copper layer 3 tightly connected from top to bottom. The outer copper layer serves as a reference ground for the microstrip line. The outer copper layer 1 includes two parallel and spaced-apart first copper strips 11. The number of first copper strips 11 can be selected according to actual needs. Each first copper strip 11 is arranged laterally and its bottom surface is tightly connected to the upper surface of the substrate 2. The inner copper layer 3 includes several parallel and spaced-apart second copper strips 31. Each second copper strip 31 is arranged longitudinally and its upper surface is tightly connected to the bottom surface of the substrate 2. Each first copper strip 11 and each second copper strip 31 is perpendicular to each other.

[0026] This solution features a simple, bend-resistant FPC structure that is easy to manufacture. Only the linewidths of the first copper strip 11 and the second copper strip 31 need to be controlled according to actual usage requirements, with low demands on processing technology. This solution sets the microstrip line's reference ground in a horizontal strip structure. This type of FPC is bend-resistant, structurally simple, and has low processing requirements, while also ensuring good impedance continuity. Here, microstrip line refers to a type of transmission line structure, and reference ground refers to the common reference plane for electrical signals. In this solution, the microstrip line's reference ground refers to the structural portion of the outer copper layer.

[0027] Specifically, a number of the second copper strips 31 can be evenly spaced.

[0028] Specifically, the length of each of the second copper strips 31 is equal to the length of the substrate 2, and the width and height of each of the second copper strips 31 can be set according to the actual use. The vertical side of the substrate 2 includes a first side 21, a second side 22, a third side, and a fourth side connected end to end in sequence, and the outer sides of the two outermost second copper strips 31 are flush with the first side 21 and the third side, respectively.

[0029] Specifically, the length of each of the first copper strips 11 is equal to the lateral width of the substrate 2, and the width and height of each of the first copper strips 11 can be set according to the actual use. When there are two first copper strips 11, the center line of the distance between the two first copper strips 11 coincides with the center line of the substrate 2.

[0030] Reference Figure 1 The bending-resistant FPC using this solution exhibits the following stress distribution on both sides during bending: Figure 2 As shown, at this point, the outer copper layer 1 is only subjected to a leftward compressive force, without any up-down tensile force. Therefore, the product's bending radius can be smaller, and it is more resistant to bending. Other conventional FPC products do not use a strip-shaped structure for the outer copper layer; during bending, the forces on the two sides are different, such as... Figure 3 As shown, the outer side of the bend is under tension, while the inner side is under compression. The stress on the outer copper is as follows. Figure 4 , Figure 4 This indicates that the outer copper is subjected to a leftward compressive force, an upward tensile force, and a downward tensile force. In summary, the FPC produced by this design is more resistant to bending than other conventional FPC products.

[0031] Other aspects of the bend-resistant FPC described in this utility model can be found in the prior art, and will not be repeated here.

[0032] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A bend-resistant FPC, characterized in that: The material includes an outer copper layer, a substrate, and an inner copper layer that are tightly connected from top to bottom. The outer copper layer includes two parallel and spaced-apart first copper strips, each of which is arranged laterally and its bottom surface is tightly connected to the upper surface of the substrate. The inner copper layer includes several parallel and spaced-apart second copper strips, each of which is arranged longitudinally and its upper surface is tightly connected to the bottom surface of the substrate.

2. The flexurally resistant FPC according to claim 1, characterized in that: The length of each of the first copper strips is equal to the lateral width of the substrate.

3. The flexurally resistant FPC according to claim 1, characterized in that: The second copper strips are spaced evenly.

4. The flexurally resistant FPC according to claim 1, characterized in that: The length of each of the second copper strips is equal to the longitudinal length of the substrate.

5. The flexurally resistant FPC according to claim 1, characterized in that: The vertical sides of the substrate include a first side, a second side, a third side, and a fourth side connected end to end, and the outer sides of the two outermost second copper strips are flush with the first side and the third side, respectively.

6. The flexurally resistant FPC according to claim 1, characterized in that: The center line of the distance between the two first copper strips coincides with the center line of the substrate.

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