Flexible circuit board with high strength and bending resistance

Abstract

The utility model discloses a flexible circuit board with high strength and bending resistance, which comprises a flexible circuit substrate and a conductive copper layer, the thickness of the conductive copper layer in a circuit bending area is larger than that of the conductive copper layer in a conducting circuit area, and a plurality of equidistant grooves are formed in the conductive copper layer in the circuit bending area so as to improve the bending resistance. The thicker copper layer can better resist stress and deformation generated during bending, and the groove design can buffer stress concentration and line extrusion deformation. In addition, the metal coating is laid on the upper surface of the conductive copper layer, the overall strength and corrosion resistance of the circuit board are improved, the upper surface of the metal coating is brushed with ink, the groove can store more ink, a solder mask protection layer is formed, the thickness and strength of the bending area are further increased, the bending curvature is relieved, the circuit board is prevented from being damaged by welding heat, and components and lines are protected.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit boards, and in particular provides a flexible circuit board with high strength and bending resistance. Background Art

[0002] COF, commonly known as Chip on Film, is a die soft film assembly technology that fixes integrated circuits on flexible circuit boards. It uses a soft additional circuit board as a chip carrier to package the chip and combine the chip with the flexible substrate circuit. Flexible materials are bendable and are often used to install chips in small spaces. They require strong bending resistance. With the development of foldable flexible screens, the market demand for products with high bending resistance has increased. Utility Model Content

[0003] The purpose of the utility model is to provide a high-strength and bend-resistant flexible circuit board, which can improve the bend-resistant performance of the product.

[0004] In order to solve the above technical problems, the present invention adopts the following solutions:

[0005] A high-strength, bend-resistant flexible circuit board comprises a flexible circuit substrate and a conductive copper layer. The surface of the flexible circuit substrate is covered with the conductive copper layer. A portion of the flexible circuit substrate is a circuit bending area that requires repeated bending. Both sides of the circuit bending area are conductive circuit areas for conductive connection. Microlithography technology is used to ensure that the thickness of the conductive copper layer in the circuit bending area is greater than that in the circuit conduction area. In addition, a plurality of equally spaced grooves are formed in the conductive copper layer in the circuit bending area, with protrusions between the grooves.

[0006] Further,

[0007] The thickness of the conductive copper layer in the circuit bending area is the distance from the top of the protrusion between the grooves of the conductive copper layer to the bottom of the conductive copper layer.

[0008] Further,

[0009] A metal plating layer is laid on the upper surface of the conductive copper layer, and the metal plating layer is in contact with the upper surface of the conductive copper layer after photolithography and etching.

[0010] Further,

[0011] The upper surface of the metal plating layer is brushed with ink, and the groove can store more ink, so that the ink height in the circuit bending area is greater than the ink height in the circuit conducting area, and the ink forms a solder resist protective layer.

[0012] Further,

[0013] The ink height in the circuit bending area is the distance from the metal plating surface at the bottom of the conductive copper layer groove to the upper surface of the solder mask.

[0014] The utility model has the beneficial effects:

[0015] 1. The whole circuit board is divided into a circuit bending area and a circuit conducting area, a groove is formed in the circuit bending area by a lithography technique, so that the thickness of the conductive copper layer of the circuit bending area is greater than the thickness of the conductive copper layer of the circuit conducting area, and the bending performance of the circuit bending area is improved.

[0016] 2. When the circuit bending area is bent, the groove can buffer stress concentration and extrusion deformation, and the bending capacity is improved.

[0017] 3. When the ink is brushed, the groove can store more ink, so that the height of the ink of the circuit bending area is higher than the height of the ink of the circuit conducting area, so that the bending capacity of the circuit bending area is improved, and a surface printing ink protective layer is further printed, the thickness of the ink protective layer is generally increased to relieve the bending curvature and improve the bending resistance. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a top view of the present utility model;

[0019] Figure 2 is a side view of the flexible circuit substrate and the conductive copper layer of the present utility model;

[0020] Figure 3 is a side view of the flexible circuit substrate and the conductive copper layer when bending;

[0021] Figure 4 is a side view of the complete utility model.

[0022] The following is a description of the drawings:

[0023] 1-flexible circuit substrate, 10-circuit conducting area, 11-circuit bending area, 2-conductive copper layer, 20-groove, 3-metal plating layer, 4-solder mask protective layer, H1-copper layer thickness of the circuit conducting area, H2-copper layer thickness of the circuit bending area, H3-ink height of the circuit bending area, H4-ink height of the circuit conducting area. DETAILED DESCRIPTION

[0024] The present utility model will be further described in detail in combination with the embodiments and drawings, but the embodiments of the present utility model are not limited thereto.

[0025] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inside", "outside", "front", "back", "top", "bottom", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the utility model product is usually placed when in use. They 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.

[0026] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "opened," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0027] Example

[0028] See also Figures 1 to 4 :

[0029] A high-strength, bend-resistant flexible circuit board comprises a flexible circuit substrate 1 and a conductive copper layer 2. The surface of the flexible circuit substrate 1 is covered with the conductive copper layer 2. A portion of the flexible circuit substrate 1 is a circuit bending region 11 that requires repeated bending. Both sides of the circuit bending region 11 are conductive circuit regions for conductive connection. Using lithography technology, the thickness H2 of the conductive copper layer in the circuit bending region is greater than the thickness H1 of the conductive copper layer in the circuit conduction region. Furthermore, a plurality of equally spaced grooves 20 are formed in the conductive copper layer 2 in the circuit bending region 11, with protrusions between the grooves 20.

[0030] Increasing the copper layer thickness in the circuit bending region 11 can improve the metal fatigue resistance of the circuit bending region 11 while reducing the bending curvature, thereby improving the bending resistance. This is because a thicker copper layer can better resist the stress and deformation generated during bending.

[0031] The groove 20 is designed to buffer stress concentration and circuit deformation during bending, thereby preventing the circuit board from breaking during the bending process. The groove 20 can absorb and disperse the stress generated during bending, reducing stress damage to the circuit board.

[0032] Further,

[0033] The thickness H2 of the conductive copper layer of the circuit bending area is the distance from the top of the protrusion between the grooves 20 of the conductive copper layer 2 to the bottom of the conductive copper layer 2.

[0034] Further,

[0035] A metal plating layer 3 is laid on the upper surface of the conductive copper layer 2, and the metal plating layer 3 is attached to the upper surface of the conductive copper layer 2 after the lithography and etching.

[0036] The metal plating layer 3 can increase the overall strength and corrosion resistance of the circuit board, and improve the stability and reliability of the circuit board. Meanwhile, the metal plating layer 3 can also form good contact with the conductive copper layer 2, and improve the conductive performance of the circuit.

[0037] Further,

[0038] The upper surface of the metal plating layer 3 is brushed with ink, and the grooves 20 can store more ink, so that the ink height H3 of the circuit bending area is greater than the ink height H4 of the circuit conducting area, and the ink forms a solder mask layer 4.

[0039] The solder mask layer 4 formed by the ink can further increase the thickness and strength of the bending area, relieve the curvature of the bending, and thus improve the bending resistance. Meanwhile, it can also prevent the heat in the soldering process from damaging the circuit board and protecting the components and circuits on the circuit board.

[0040] Further,

[0041] The ink height H3 of the circuit bending area is the distance from the surface of the metal plating layer 3 at the bottom of the groove 20 of the conductive copper layer 2 to the upper surface of the solder mask layer 4. The design principle of the utility model is:

[0042] The utility model makes use of the principle that increasing the thickness of the material can increase the bending capacity of the material, changes the thickness of the conductive copper layer 2 on the circuit bending area 11 by setting the grooves 20 on the conductive copper layer 2, so that there is a height difference between the conductive copper layer 2 on the circuit bending area 11 and the circuit conducting area 10, and the thickness of the conductive copper layer 2 on the circuit bending area 11 is greater than that of the circuit conducting area 10, and the bending capacity of the circuit bending area 11 is improved.

[0043] Then a metal plating layer 3 is attached to the upper surface of the conductive copper layer 2. It should be noted that the thickness of the metal plating layer 3 should be less than the height of the groove 20, so that after the metal plating layer 3 is set on the conductive copper layer 2, there is still a groove 20, and then ink is brushed on the surface of the metal plating layer 3 to form a solder mask layer 4. When brushing the ink, the groove 20 can store more ink, so that the ink thickness of the circuit bending area 11 is greater than that of the circuit conducting area 10. According to the principle used, the bending resistance of the circuit bending area 11 is stronger.

[0044] Due to the presence of the groove 20 , when the present invention is bent at the bending zone, the groove 20 can enhance the bending resistance of the circuit bending zone 11 .

[0045] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Based on the technical essence of the present invention and within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement of the above embodiment shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A high-strength and bend-resistant flexible circuit board, comprising a flexible circuit substrate (1) and a conductive copper layer (2), characterized in that: The surface of the flexible circuit substrate (1) is covered with a conductive copper layer (2); a portion of the flexible circuit substrate (1) is a circuit bending area (11) that needs to be repeatedly bent; both sides of the circuit bending area (11) are conductive circuit areas for conduction connection; a photolithography technique is used to make the thickness (H2) of the conductive copper layer in the circuit bending area greater than the thickness (H1) of the conductive copper layer in the circuit conduction area; and a plurality of grooves (20) with equal spacing are formed in the conductive copper layer (2) in the circuit bending area (11), with protrusions between the grooves (20).

2. The high-strength, bendable flexible circuit board according to claim 1, characterized in that: The thickness (H2) of the conductive copper layer in the circuit bending area is the distance from the top of the protrusion between the grooves (20) of the conductive copper layer (2) to the bottom of the conductive copper layer (2).

3. The high-strength and bend-resistant flexible circuit board according to claim 2, characterized in that: A metal plating layer (3) is laid on the upper surface of the conductive copper layer (2), and the metal plating layer (3) is in contact with the upper surface of the conductive copper layer (2) after microlithography.

4. The high-strength and bend-resistant flexible circuit board according to claim 3, characterized in that: The upper surface of the metal plating layer (3) is brushed with ink, and the groove (20) can store more ink, so that the ink height (H3) of the circuit bending area is greater than the ink height (H4) of the circuit conducting area, and the ink forms a solder resist protective layer (4).

5. The high-strength and bend-resistant flexible circuit board according to claim 4, characterized in that: The ink height (H3) of the circuit bending area is the distance from the surface of the metal plating layer (3) at the bottom of the groove (20) of the conductive copper layer (2) to the upper surface of the solder mask (4).

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