Flexible circuit board

Abstract

The invention discloses a flexible circuit board which comprises a base material layer, a conductive layer, an enhancement layer, an insulating layer and a heat dissipation layer. The conductive layers are arranged on the upper surface and the lower surface of the base material layer and have a wave-shaped circuit structure; the enhancement layer covers the bending area of the conductive layer; the insulating layer covers the surface of the enhancement layer; the heat dissipation layer covers the surface of the insulating layer, and the heat dissipation layer comprises a composite structure of a graphene film and a metal grid. The composite material has the advantages of high bending resistance, strong interlayer bonding force and excellent heat dissipation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit boards, and particularly to a flexible circuit board. Background Art

[0002] Flexible printed circuits (FPCs) are widely used in electronic devices that need to be bent, such as wearable devices and folding screen mobile phones. In the prior art, traditional flexible printed circuits have the following problems:

[0003] 1. When multiple layers of circuits are stacked, the circuits are easily broken due to bending;

[0004] 2. The interlayer bonding force is insufficient, and delamination is likely to occur after long-term use;

[0005] 3. The heat dissipation performance is poor, which affects the stability of high-density electronic components.

[0006] Therefore, there is an urgent need for a flexible printed circuit with an optimized structure to solve the above problems. Summary of the Invention

[0007] In view of the above problems, the present invention provides a flexible printed circuit with high bending resistance, strong interlayer bonding force and excellent heat dissipation performance.

[0008] The technical solution of the present invention is as follows:

[0009] A flexible printed circuit includes a substrate layer, a conductive layer, a reinforcing layer, an insulating layer and a heat dissipation layer; the conductive layer is disposed on the upper and lower surfaces of the substrate layer and has a wavy circuit structure; the reinforcing layer covers the bent area of the conductive layer; the insulating layer covers the surface of the reinforcing layer; the heat dissipation layer covers the surface of the insulating layer, and the heat dissipation layer includes a composite structure of a graphene film and a metal grid.

[0010] In a further technical solution, the substrate layer is a polyimide film with a thickness of 10-50 μm.

[0011] In a further technical solution, the wave crest spacing of the wavy circuit structure of the conductive layer is 0.1-0.5 mm.

[0012] In a further technical solution, the metal grid of the heat dissipation layer is made of copper-nickel alloy with a grid density of 200-500 meshes.

[0013] In a further technical solution, the connection terminal of the conductive layer adopts a stepped end design and is plated with a gold layer with a thickness of 1-3 μm.

[0014] The beneficial effects of the present invention are:

[0015] The present invention has high bending resistance, strong interlayer bonding force and excellent heat dissipation performance. Brief Description of the Drawings

[0016] Figure 1 This is a schematic structural diagram of the flexible printed circuit board according to an embodiment of the present invention.

[0017] Explanation of reference numerals in the drawings:

[0018] 10, substrate layer; 20, conductive layer; 30, reinforcing layer; 40, insulating layer; 50, heat dissipation layer. Detailed implementation manners

[0019] The following further describes the embodiments of the present invention with reference to the accompanying drawings.

[0020] Embodiment:

[0021] A flexible printed circuit board, as Figure 1 shown, includes a substrate layer, a conductive layer, a reinforcing layer, an insulating layer and a heat dissipation layer; the conductive layer is disposed on the upper and lower surfaces of the substrate layer and has a wavy circuit structure; the reinforcing layer covers the bent area of the conductive layer; the insulating layer covers the surface of the reinforcing layer; the heat dissipation layer covers the surface of the insulating layer, and the heat dissipation layer includes a composite structure of a graphene film and a metal grid; a stepped transition structure is provided between the substrate layer and the conductive layer, and between the conductive layer and the reinforcing layer, the step height is 5-15 μm, and the width of a single-stage step is 0.1-0.3 mm.

[0022] In another embodiment, the substrate layer is a polyimide film with a thickness of 10-50 μm.

[0023] In another embodiment, the wave crest spacing of the wavy circuit structure of the conductive layer is 0.1-0.5 mm.

[0024] In another embodiment, the metal grid of the heat dissipation layer is made of copper-nickel alloy, and the grid density is 200-500 meshes.

[0025] In another embodiment, the connection terminal of the conductive layer adopts a stepped end design, and the surface is plated with a gold layer with a thickness of 1-3 μm.

[0026] In another embodiment, the surface of the step is treated by plasma, the roughness Ra≥0.5 μm, and the step gap is filled with modified epoxy resin.

[0027] In another embodiment, the stepped transition structures between the reinforcing layer and the bent area of the conductive layer are arranged in a staggered manner, and the distance between the two is 0.05-0.2 mm.

[0028] The above-described embodiments merely represent specific implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention.

Claims

1. A flexible printed circuit board, characterized in that, It includes a substrate layer, a conductive layer, a reinforcement layer, an insulating layer, and a heat dissipation layer; the conductive layer is disposed on the upper and lower surfaces of the substrate layer and has a wavy circuit structure; the reinforcement layer covers the bent area of the conductive layer; the insulating layer covers the surface of the reinforcement layer; the heat dissipation layer covers the surface of the insulating layer, and the heat dissipation layer comprises a composite structure of a graphene film and a metal grid.

2. The flexible printed circuit board according to claim 1, characterized in that, The substrate layer is a polyimide film with a thickness of 10 - 50 μm.

3. The flexible printed circuit board according to claim 1, wherein The peak-to-peak distance of the wavy circuit structure of the conductive layer is 0.1 - 0.5 mm.

4. The flexible printed circuit board according to claim 1, wherein The metal grid of the heat dissipation layer is made of copper-nickel alloy with a mesh density of 200 - 500 meshes.

5. The flexible printed circuit board according to claim 1, characterized in that, The connection terminals of the conductive layer adopt a stepped end design and are plated with a 1 - 3 μm thick gold layer on the surface.

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