Flexible circuit board and display device

Abstract

The utility model provides a flexible circuit board and a display device, relates to the technical field of display, and aims to avoid fatigue cracks of a connecting part and improve the mechanical stability and reliability of the flexible circuit board. The display panel comprises a main body part and a connecting part. The main body part comprises a plurality of first conductive layers and a plurality of first insulating layers, and the plurality of first conductive layers and the plurality of first insulating layers are alternately stacked. A first pin is arranged on one side of at least one first conductive layer in the plurality of first conductive layers, the first pin is configured to be electrically connected with the display panel, and the main body part further comprises a first connecting structure. The connecting part comprises a plurality of second conducting layers and a plurality of second insulating layers, the second conducting layers and the second insulating layers are alternately stacked, the connecting part further comprises a second connecting structure, one end of the connecting part is connected with the first connecting structure through the second connecting structure, and the other end of the connecting part is connected with the mainboard after being bent.

Description

Technical Field

[0001] This application relates to the field of display technology, and more particularly to a flexible circuit board and a display device. Background Technology

[0002] Currently, foldable products generally adopt a flexible cover design. During operation, frequent touching and pressing of the flexible screen will cause the screen to generate a micro-motion environment. This will transfer stress to the internal motherboard, and then to the flexible circuit board. Under long-term micro-motion bending, fatigue cracks are prone to appear at the connection parts of the flexible circuit board. This will not only reduce the product's service life, but may also cause a series of functional problems, seriously affecting the user experience. Utility Model Content

[0003] This application proposes a flexible circuit board and a display device, which aims to avoid fatigue cracks at the connection points and improve the mechanical stability and reliability of the flexible circuit board.

[0004] To achieve the above objectives, embodiments of this application provide the following technical solutions:

[0005] On the one hand, a flexible circuit board is provided, including a main body and a connecting part.

[0006] The main body includes multiple first conductive layers and multiple first insulating layers, which are alternately stacked. A first pin is provided on one side of at least one of the multiple first conductive layers, and the first pin is configured to be electrically connected to the display panel; the main body also includes a first connection structure.

[0007] The connecting part includes multiple second conductive layers and multiple second insulating layers, which are alternately stacked. The connecting part also includes a second connecting structure. One end of the connecting part is connected to the first connecting structure through the second connecting structure, and the other end is bent and configured to connect to the motherboard.

[0008] In this application, the main body and the connecting part are separately disposed. The first pin of the main body is configured to connect to the display panel, and the first connecting structure is connected to the second connecting structure, thereby realizing the electrical connection between the main body and the connecting part. The other end of the connecting part is bent and configured to connect to the motherboard, so that the flexible circuit board can realize the function of transmitting relevant signals from the motherboard to the display panel. The main body and the connecting part are reliably connected to the first connecting structure through the second connecting structure, which is beneficial to optimizing the stress distribution of the main body and the connecting part in a micro-motion environment, improving the mechanical stability and reliability of the flexible circuit board, achieving a balance between the dynamic and static performance of the flexible circuit board, and enhancing the user experience. The separate disposal of the main body and the connecting part allows them to be manufactured or reworked separately, which is beneficial to optimizing the manufacturing process of the flexible circuit board and reducing production costs.

[0009] In some embodiments, along the direction in which the first conductive layer and the first insulating layer are alternately stacked, the first connection structure is disposed on the outermost side of the plurality of first conductive layers. Along the direction in which the second conductive layer and the second insulating layer are alternately stacked, the second connection structure is disposed on the outermost side of the plurality of second conductive layers.

[0010] In some embodiments, the material of at least one first conductive layer includes electrolytic copper, and the material of at least one second conductive layer includes rolled copper.

[0011] In some embodiments, the material of the plurality of first conductive layers of the main body includes electrolytic copper, and the material of the plurality of second conductive layers of the connecting portion includes rolled copper.

[0012] In some embodiments, both the first connection structure and the second connection structure are solder pads.

[0013] In some embodiments, the orthographic projection of the first connecting structure onto the main body is a circle, an ellipse, or a semicircle. And / or, the orthographic projection of the second connecting structure onto the main body is a circle, an ellipse, or a semicircle.

[0014] In some embodiments, the surface of the first connecting structure is provided with a plating layer. And / or, the surface of the second connecting structure is provided with a plating layer.

[0015] In some embodiments, the flexible circuit board further includes a buffer layer disposed between the first connection structure and the second connection structure, and the material of the buffer layer includes anisotropic conductive film or flexible polymer.

[0016] In some embodiments, the material of at least one first conductive layer includes electrolytic copper, and the material of at least one second conductive layer includes rolled copper. The flexible circuit board also includes a transition layer disposed between the first connection structure and the second connection structure, wherein the coefficient of thermal expansion of the transition layer is between that of electrolytic copper and rolled copper.

[0017] In some embodiments, the flexible circuit board further includes a heat dissipation structure that encloses at least a portion of the first connection structure. And / or, the heat dissipation structure encloses at least a portion of the second connection structure.

[0018] In some embodiments, the surface of the main body is provided with a plurality of heat dissipation holes, which are arranged around the first connecting structure and penetrate at least one first conductive layer. And / or, the surface of the connecting portion is provided with a plurality of heat dissipation holes, which are arranged around the second connecting structure and penetrate at least one second conductive layer.

[0019] In some embodiments, the flexible circuit board further includes a heat sink, one end of which is connected to the side surface of the main body near the first connection structure, and the other end of which is connected to the side surface of the connection portion away from the second connection structure.

[0020] In some embodiments, one of the first connection structure and the second connection structure is a board-to-board connector male socket and the other is a board-to-board connector female socket, and the board-to-board connector male socket and the board-to-board connector female socket are fastened together.

[0021] In some embodiments, the first connection structure is a zero-insertion-force connector, and the second connection structure is a second pin, which is inserted into the zero-insertion-force connector.

[0022] In another aspect, a display device is provided, comprising a display panel, a motherboard, and a flexible circuit board as described in any of the above embodiments. The flexible circuit board is located on the non-light-emitting side of the display panel, and the main body of the flexible circuit board is electrically connected to the display panel, while the connecting portion of the flexible circuit board is electrically connected to the motherboard.

[0023] In some embodiments, the display panel includes a first portion for display and a second portion for bonding, the second portion being bent to the non-light-emitting side of the first portion. The main body of the flexible circuit board is electrically connected to the second portion.

[0024] In some embodiments, a third pin is provided on the surface of the second part away from the first part, and the main body is electrically connected to the third pin through the first pin.

[0025] The above-described display device has the same structure and beneficial technical effects as the display panel provided in some of the above embodiments, and will not be described again here. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in some embodiments of this application will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not actual dimensions of the products or actual processes of the methods involved in the embodiments of this application.

[0027] Figure 1 This is a schematic diagram of the structure of a first type of flexible circuit board provided in an embodiment of this application;

[0028] Figure 2 This is a schematic diagram of the structure of a second type of flexible circuit board provided in an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of the structure of a third type of flexible circuit board provided in an embodiment of this application;

[0030] Figure 4 This is a schematic diagram of the structure of the fourth type of flexible circuit board provided in the embodiments of this application;

[0031] Figure 5 for Figure 4 The diagram shows a top view of the flexible circuit board at the second connection structure.

[0032] Figure 6 A top view of a flexible circuit board at the second connection structure provided in an embodiment of this application;

[0033] Figure 7 This is a schematic diagram of the structure of the fifth type of flexible circuit board provided in the embodiments of this application;

[0034] Figure 8 This is a schematic diagram of the structure of the sixth type of flexible circuit board provided in the embodiments of this application;

[0035] Figure 9 This is a structural schematic diagram of the seventh type of flexible circuit board provided in the embodiments of this application;

[0036] Figure 10 This is a schematic diagram of the structure of a display device provided in an embodiment of this application;

[0037] Figure 11 This is a schematic diagram of the structure of a display panel provided in an embodiment of this application. Detailed Implementation

[0038] The technical solutions in some embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application are within the scope of protection of this application.

[0039] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open and encompassing, that is, "including, but not limited to".

[0040] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0041] In describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be interpreted broadly; for example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. For example, in describing some embodiments, the term "connection" may be used to indicate that two or more components have direct physical or electrical contact with each other.

[0042] In addition, the use of “based on” implies openness and inclusivity, because processes, steps, calculations or other actions “based on” one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0043] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0044] This document describes exemplary embodiments with reference to cross-sectional views, which are intended as idealized exemplary drawings. In the drawings, the thickness of the layers and the area of ​​the regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include shape deviations caused, for example, by manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0045] In some electronic products, a flexible circuit board (FPCB) is electrically connected to the display panel on one side via pins, and to the motherboard on the other side after being bent. Under prolonged micro-bending, fatigue cracks can easily appear at the connection points of the FPCB. This not only reduces the product's lifespan but may also cause a series of functional problems, seriously affecting the user experience.

[0046] Based on this, this application provides a flexible circuit board, which aims to improve fatigue cracking problems and enhance the mechanical stability and reliability of the flexible circuit board.

[0047] like Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of the first flexible circuit board provided in the embodiments of this application.

[0048] The flexible circuit board 100 includes a main body 10 and a connecting part 20.

[0049] The main body 10 includes a plurality of first conductive layers 11 and a plurality of first insulating layers 12, which are alternately stacked. A first pin 13 is provided on one side of at least one of the plurality of first conductive layers 11, and the first pin 13 is configured to be electrically connected to the display panel 2. The main body 10 also includes a first connection structure 14.

[0050] The connecting part 20 includes a plurality of second conductive layers 21 and a plurality of second insulating layers 22, which are alternately stacked. The connecting part 20 also includes a second connecting structure 23. One end of the connecting part 20 is connected to the first connecting structure 14 through the second connecting structure 23, and the other end is bent and configured to be connected to the motherboard 3.

[0051] In this application, the main body 10 and the connecting part 20 are separately disposed, and the first pin 13 of the main body 10 is configured to connect to the display panel 2. The first connecting structure 14 is connected to the second connecting structure 23, thereby realizing the electrical connection between the main body 10 and the connecting part 20. The other end of the connecting part 20 is bent and configured to connect to the motherboard 3, so that the flexible circuit board 100 can realize the function of transmitting relevant signals of the motherboard 3 to the display panel 2.

[0052] The main body 10 and the connecting part 20 are reliably connected by the first connecting structure 14 and the second connecting structure 23. This facilitates the optimization of stress distribution between the main body 10 and the connecting part 20 under micro-motion conditions. For example, increasing the overlap area of ​​the main body 10 and the connecting part 20 helps to disperse the stress on the connecting part 20, improves the mechanical stability and reliability of the flexible circuit board 100, helps to achieve a balance between dynamic and static performance of the flexible circuit board 100, and enhances the user experience. Furthermore, the main body 10 and the connecting part 20 can be manufactured or repaired separately. In the event of damage to the connecting part 20, only the connecting part 20 can be repaired or replaced, solving the problem that the connecting part 20 of the flexible circuit board 100 cannot be repaired. This helps to optimize the manufacturing process of the flexible circuit board 100 and reduce production costs.

[0053] For example, such as Figure 1 As shown, along the direction in which the first conductive layer 11 and the first insulating layer 12 are alternately stacked, the first connection structure 14 is disposed on the outermost side of the plurality of first conductive layers 11. The first connection structure 14 penetrates at least through the outermost first insulating layer 12 and is electrically connected to the first conductive layer 11 inside the main body 10 to realize signal transmission.

[0054] Along the direction in which the second conductive layer 21 and the second insulating layer 22 are alternately stacked, the second connection structure 23 is disposed on the outermost side of the plurality of second conductive layers 21. The second connection structure 23 penetrates at least through the outermost second insulating layer 22 and is electrically connected to the second conductive layer 21 within the connection portion 20 to enable signal transmission.

[0055] Based on this, the first connecting structure 14 is connected to the second connecting structure 23, thereby realizing the electrical connection between the main body 10 and the connecting part 20.

[0056] In some embodiments, such as Figure 1 As shown, at least one first conductive layer 11 is made of electrolytic copper, and at least one second conductive layer 21 is made of rolled copper.

[0057] The conductive layers of the flexible circuit board 100 (including the first conductive layer 11 and the second conductive layer 21) can be used for wiring design or for signal shielding. The first pin 13 of the main body 10 is configured to be electrically connected to the display panel 2, the first connection structure 14 is electrically connected to the second connection structure 23 of the connection part 20, and the other end of the connection part 20 is electrically connected to the motherboard 3. In some embodiments, the flexible circuit board 100 further includes a device area 4, which includes passive components such as resistors, capacitors, or inductors, and may also include active components such as driver chips, transistors, and clock circuits. Ultimately, the flexible circuit board 100 can realize the electrical connection between the display panel 2 and the motherboard 3, or the electrical connection between the display panel 2 and the corresponding components in the device area 4, thereby enabling the display panel 2 to display an image.

[0058] The number of conductive layers can be designed as needed. Figure 1 Taking the main body 10 shown as an example, the main body 10 includes six first conductive layers 11, which can be sequentially referred to as layers one through six along the direction gradually moving away from the motherboard 3. For example, the first pin 13 is located on the lower side of the third layer, and the corresponding traces electrically connected to the display panel 2 are routed within the third layer. The traces within the third layer can be electrically connected to traces in other layers through vias within the main body 10. Alternatively, the first pin 13 is located on one side of the third layer and is electrically connected to traces in the second layer through vias. The corresponding traces electrically connected to the display panel 2 are routed within the second layer, and the traces in the second layer can be electrically connected to traces in other layers through vias within the main body 10.

[0059] Typically, the number of first pins 13 electrically connected to the display panel 2 is relatively large. To ensure the product's small size requirement, the first pins 13 must meet high dimensional accuracy requirements. Within the connection section 20, the wiring design is mainly used to achieve electrical connection with the motherboard 3. The number of pins at the second connection structure 23 is smaller, and the dimensional accuracy requirements for the second connection structure 23 are lower.

[0060] In this application, the material of at least one first conductive layer 11 of the main body 10 includes electrolytic copper, for example, such as... Figure 1 The material of the first conductive layer 11 of the third layer shown is electrolytic copper. Electrolytic copper refers to copper foil formed by depositing copper ions on the cathode through electrolysis of copper sulfate solution using electrochemical principles. Electrolytic copper has a columnar crystalline structure, lower production costs, and can meet manufacturing processes requiring high dimensional accuracy.

[0061] In other words, electrolytic copper, due to its excellent processing precision and good conductivity, helps ensure the high efficiency and high reliability of the flexible circuit board 100 under static conditions. Furthermore, the manufacturing process of electrolytic copper is mature, facilitating large-scale production and quality control. During production, electrolytic copper offers strong dimensional accuracy control, which helps ensure process quality and consistency in achieving the electrical connection between the first pin 13 and the display panel 2, thus meeting high-precision manufacturing requirements. Moreover, the preparation process is simple, mature, and low-cost, which is beneficial for the fabrication of the main body 10.

[0062] Furthermore, the material of at least one second conductive layer 21 of the connecting portion 20 includes rolled copper, for example, such as... Figure 1 As shown, the material of the second conductive layer 21 near the main body 10 includes rolled copper. Rolled copper is manufactured through a physical rolling process, in which copper ingots or plates are heated and repeatedly rolled and annealed to ultimately form the desired copper foil or strip. Rolled copper has a lamellar crystalline structure, high purity, and good flexibility, making it suitable for applications requiring frequent bending.

[0063] In other words, rolled copper has better flexibility and durability, and can maintain high structural integrity and electrical conductivity in frequent bending and micro-motion environments. By using rolled copper materials, the reliability of flexible circuit board 100 in micro-motion environments can be improved, the risk of cracking can be reduced, and the product's service life and stability can be improved.

[0064] Based on this, this application can ensure a reliable connection between the flexible circuit board 100 and the display panel 2, and also ensure the service life and reliability of the flexible circuit board 100 in a micro-motion environment, achieving the best balance between dynamic and static performance of the flexible circuit board 100, which is conducive to improving the user experience.

[0065] In some embodiments, such as Figure 1 As shown, the material of the plurality of first conductive layers 11 of the main body 10 includes electrolytic copper, and the material of the plurality of second conductive layers 21 of the connecting part 20 includes rolled copper.

[0066] For example, the main body 10 includes six first conductive layers 11, each made of electrolytic copper. The wiring design on any one of the first conductive layers 11 can be achieved by "laminating electrolytic copper foil to the surface of the first insulating layer 12 to form a copper-clad laminate, and then transferring the designed circuit pattern to the copper-clad laminate using techniques such as photolithography or laser direct imaging." Multiple first conductive layers 11 are laminated together to form a multi-layer structure of the main body 10. Electrical connections between the upper and lower layer wirings can be achieved through processes such as drilling and copper plating.

[0067] like Figure 1 As shown, the material of the six first conductive layers 11 of the main body 10 all includes electrolytic copper. Theoretically, the first pin 13 can be located in any layer. To achieve better wiring design and reduce the number of vias in the main body 10, for example, the first pin 13 is located in the third layer. The wiring that is electrically connected to the display panel 2 is partially connected upwards through vias in the main body 10 to the wiring in the first and second layers, and another part is connected to the wiring in the same layer (the third layer), ultimately achieving electrical connection with the device area 4 and the motherboard 3. Another part of the wiring is connected downwards through vias in the main body 10 to the wiring in the fifth and sixth layers. The fourth layer serves as a shielding layer, and the wiring in the fifth and sixth layers is connected upwards through vias in the main body 10 to the corresponding components at appropriate locations.

[0068] Based on this, the routing within the main body 10 can be partitioned and grouped, allowing full utilization of the routing space in the multiple first conductive layers 11 of the main body 10. Shielding layers separate interfering routing lines, preventing increased spacing between interfering lines due to a lack of shielding, thus avoiding an increase in the size of the main body 10. Furthermore, a reasonable partitioned and grouped routing design reduces the number of board layers penetrated by vias, optimizes routing layout, reduces unnecessary vias, minimizes the impact of vias on the performance of the flexible circuit board 100, reduces manufacturing complexity, ensures signal transmission quality and reliability on the routing lines, and improves the performance and reliability of the flexible circuit board 100.

[0069] Similarly, such as Figure 1 As shown, the connection portion 20 includes two second conductive layers 21, each of which is made of rolled copper. Both second conductive layers 21 can be used for wiring design, which helps to reduce the area of ​​the connection portion 20. Furthermore, the two second conductive layers 21 and three second insulating layers 22 are alternately stacked, increasing the thickness of the connection portion 20, which helps to enhance the strength of the flexible circuit board 100 and avoid fatigue cracks.

[0070] In some embodiments, both the first connecting structure 14 and the second connecting structure 23 are solder pads. The surfaces of the main body 10 and the connecting portion 20 overlap and are fixed by soldering through the solder pads, which helps to disperse the stress on the connecting portion 20 and improves the connection strength and reliability between the main body 10 and the connecting portion 20.

[0071] For example, the orthographic projection of the first connecting structure 14 onto the main body 10 is a circle, an ellipse, or a semicircle. And / or, the orthographic projection of the second connecting structure 23 onto the main body 10 is a circle, an ellipse, or a semicircle.

[0072] The shape and size of the pads in the first connection structure 14 match the shape and size of the pads in the second connection structure 23, ensuring reliability and consistency during soldering. The pads are circular, elliptical, or semi-circular in shape, which can distribute shear stress using geometry, increasing tensile strength by approximately 30% compared to conventional square pads.

[0073] The welding between the first connecting structure 14 and the second connecting structure 23 can be performed using laser welding or ultrasonic welding technology. Laser welding uses a high-energy-density laser beam to melt and connect the pads together; for example, setting the laser power to 100W, the welding speed to 10mm / s, and the focal length to 10mm. Ultrasonic welding uses heat generated by high-frequency vibration to melt and connect the pads together; for example, setting the amplitude to 20μm, the welding time to 0.5 seconds, and the pressure to 0.5MPa. During the welding process, a high-resolution camera is used to monitor the welding points in real time to ensure that there are no bubbles, no incomplete welds, and no over-welding. After welding, tensile and electrical tests are also required to ensure that the mechanical strength and electrical performance of the weld meet the design requirements. By rationally selecting the welding process and controlling the process parameters, the connection quality can be ensured, and the connection strength and reliability of the main body 10 and the connecting part 20 can be improved.

[0074] In some embodiments, such as Figure 1 As shown, the surface of the first connecting structure 14 is provided with a plating layer 31. Alternatively, the surface of the second connecting structure 23 is provided with a plating layer 31. Or, the surface of both the first connecting structure 14 and the second connecting structure 23 are provided with a plating layer 31.

[0075] The material of the plating layer 31 may include tin or silver. By plating the surface of the pads with tin or silver, the soldering quality can be improved, oxidation can be prevented, the connection reliability between the first connection structure 14 and the second connection structure 23 can be improved, and the service life of the flexible circuit board 100 can be increased.

[0076] The main body 10 and the connecting part 20 are electrically connected through the first connecting structure 14 and the second connecting structure 23. The heat generation problem is more obvious near the first connecting structure 14 and the second connecting structure 23. Large temperature changes may lead to stress concentration and thus affect the reliability of the product. Reasonable thermal management is conducive to improving the long-term reliability of the product.

[0077] In some embodiments, such as Figure 2 As shown, Figure 2 This is a schematic diagram of the structure of a second type of flexible circuit board provided in an embodiment of this application. The flexible circuit board 100 also includes a buffer layer 32, which is disposed between the first connecting structure 14 and the second connecting structure 23. For example, the first connecting structure 14 and the second connecting structure 23 can be fixed on both sides of the buffer layer 32 by heat-press bonding.

[0078] The material of the buffer layer 32 may include anisotropic conductive film (ACF) or other flexible polymers. These materials have good thermal expansion characteristics and flexibility, and can absorb some stress when the temperature changes, reducing the direct stress transmission between rolled copper and electrolytic copper. The conductive particles added to the material can also achieve good electrical connection, thereby improving the reliability and durability of the connection.

[0079] In some embodiments, such as Figure 3 As shown, Figure 3 This is a schematic diagram of the structure of a third type of flexible circuit board provided in an embodiment of this application. The flexible circuit board 100 further includes a transition layer 33, which is disposed between the first connection structure 14 and the second connection structure 23. The thermal expansion coefficient of the transition layer 33 is between that of electrolytic copper and rolled copper.

[0080] For example, the material of the transition layer 33 includes a copper-nickel alloy. The coefficients of thermal expansion of electrolytic copper, copper-nickel alloy and rolled copper are in a gradient transition. Through the layer-by-layer gradient transition, thermal stress can be reduced, the difference in thermal expansion between electrolytic copper and rolled copper can be effectively alleviated, and stress concentration can be reduced.

[0081] In some embodiments, such as Figures 4-5 As shown, Figure 4 This is a schematic diagram of the structure of the fourth type of flexible circuit board provided in the embodiments of this application. Figure 5 for Figure 4 The diagram shows a top view of the flexible circuit board at the second connection structure.

[0082] The flexible circuit board 100 also includes a heat dissipation structure 34, which, for example, is a thermally conductive adhesive.

[0083] The heat dissipation structure 34 encloses at least a portion of the first connecting structure 14. Alternatively, the heat dissipation structure 34 encloses at least a portion of the second connecting structure 23. Or, the heat dissipation structure 34 encloses at least a portion of both the first connecting structure 14 and the second connecting structure 23.

[0084] like Figures 4-5 As shown, the thermally conductive adhesive applied around the first connecting structure 14 and the second connecting structure 23 can help conduct heat from the high-temperature area to the low-temperature area, thereby improving the overall heat dissipation capability.

[0085] In some embodiments, the thermally conductive adhesive not only achieves efficient heat conduction but also provides multiple protective properties. For example, the thermally conductive adhesive can form a dense protective barrier on the surfaces of the first connecting structure 14 and the second connecting structure 23, forming a physical protective layer that effectively blocks moisture penetration (moisture resistance up to IPX7 standard) and salt spray corrosion (verified by a 240-hour 5% NaCl salt spray test). The thermally conductive adhesive can also utilize a special formulation to neutralize acidic / alkaline contaminants, inhibiting electrochemical corrosion and ion migration, forming a chemical protection system. Alternatively, the elastic modulus of the thermally conductive adhesive can be controlled within the range of 3.5–4.2 MPa, absorbing ±15% of deformation stress, which helps buffer mechanical stress and improves the connection reliability of the first connecting structure 14 and the second connecting structure 23.

[0086] In some embodiments, such as Figure 6 As shown, Figure 6 This is a top view of a flexible circuit board at the second connection structure, provided in an embodiment of this application. The surface of the main body 10 is provided with a plurality of heat dissipation holes K1, which surround the first connection structure 14 and penetrate at least one first conductive layer 11. Alternatively, the surface of the connection portion 20 is provided with a plurality of heat dissipation holes K1, which surround the second connection structure 23 and penetrate at least one second conductive layer 21. Or, the plurality of heat dissipation holes K1 surround both the first connection structure 14 and the second connection structure 23.

[0087] For example, taking the main body 10 as having six first conductive layers 11, the heat dissipation hole K1 can penetrate one or more of the six first conductive layers 11. The setting of the heat dissipation hole K1 does not affect the wiring design. The principle for setting the heat dissipation hole K1 around the second connection structure 23 is the same, and will not be repeated here. By setting the heat dissipation hole K1, it is beneficial to increase the heat dissipation surface area, improve the heat dissipation efficiency, and improve the long-term reliability of the product.

[0088] In some embodiments, such as Figure 7 As shown, Figure 7 This is a schematic diagram of the structure of the fifth type of flexible circuit board provided in the embodiments of this application.

[0089] The flexible circuit board 100 also includes a heat sink 35, one end of which is connected to the side surface of the main body 10 near the first connecting structure 14, and the other end is connected to the side surface of the connecting part 20 away from the second connecting structure 23.

[0090] For example, the material of the heat sink 35 may include graphite. A heat dissipation metal sheet 36 may also be provided on the surface of the main body 10 near the first connecting structure 14. Similarly, a heat dissipation metal sheet 36 may also be provided on the surface of the connecting part 20 away from the second connecting structure 23. The material of the heat dissipation metal sheet 36 may include steel, aluminum, or copper.

[0091] Graphite, steel, aluminum, or copper all have good thermal conductivity. Increasing the heat dissipation area can improve heat dissipation efficiency and enhance the long-term reliability of the product.

[0092] In some embodiments, such as Figure 8 As shown, Figure 8 This is a schematic diagram of the structure of the sixth type of flexible circuit board provided in the embodiments of this application. One of the first connection structure 14 and the second connection structure 23 is a board-to-board connector male socket, and the other is a board-to-board connector female socket, which are fastened together.

[0093] That is, the main body 10 and the connecting part 20 are fastened together by a board-to-board (BTB) connection. The connection method is simple, which not only provides a stable electrical connection, but also allows for easy disassembly when needed, making it convenient to replace damaged parts, thereby achieving non-destructive repair, which is conducive to improving production efficiency and product quality, and reducing maintenance costs.

[0094] In some embodiments, such as Figure 9 As shown, Figure 9 This is a schematic diagram of the structure of the seventh flexible circuit board provided in the embodiments of this application. The first connection structure 14 is a zero insertion force connector, and the second connection structure 23 is a second pin, which is inserted into the zero insertion force connector.

[0095] That is, the main body 10 and the connecting part 20 are connected by a zero insertion force (ZIF) method. The connection method is simple. The main body 10 uses a socket with a clamp, and the second pin of the connecting part 20 is inserted into the socket through the clamp. The feature of this connection method is that no additional insertion force is required when inserting or pulling out. The zero insertion force connector can automatically clamp or release the second pin, which helps to ensure the stability and reliability of the connection.

[0096] like Figure 8 or Figure 9In the flexible circuit board 100 shown, the connection method between the main body 10 and the connecting part 20 allows the connecting part 20 to be easily disassembled without the need for additional tools or excessive force. This not only reduces wear on the flexible circuit board 100 but also lowers the risk of damage during rework. When a faulty component needs to be replaced, this connection method allows for quick replacement without complex soldering or disassembly operations. In other words, it not only solves the problem of the connecting part 20 of the flexible circuit board 100 being unrepairable but also provides an efficient solution for non-destructive rework and faulty component replacement, greatly improving maintenance efficiency, reducing downtime, and increasing overall production efficiency. This makes the flexible circuit board 100 suitable for various electronic devices requiring high reliability and high maintenance efficiency.

[0097] Secondly, this application also provides a display device, such as... Figure 10 As shown, Figure 10 This is a schematic diagram of the structure of a display device provided in an embodiment of this application. Figure 11 This is a schematic diagram of the structure of a display panel provided in an embodiment of this application.

[0098] The display device 200 includes a display panel 2, a motherboard 3, and a flexible circuit board 100 in any of the above embodiments.

[0099] The display panel 2 includes a light-emitting side P1 and a non-light-emitting side P2. The flexible circuit board 100 is located on the non-light-emitting side P2 of the display panel 2, and the main body 10 of the flexible circuit board 100 is electrically connected to the display panel 2. The connecting part 20 of the flexible circuit board 100 is electrically connected to the main board 3.

[0100] For example, the display device 200 is a foldable display product, which is frequently touched and pressed during daily operation, thus creating a micro-motion environment. The main body 10 and the connecting part 20 of the flexible circuit board 100 are separately disposed, and are reliably connected by a first connecting structure 14 and a second connecting structure 23. This facilitates the optimization of stress distribution between the main body 10 and the connecting part 20 in a micro-motion environment. For example, increasing the overlap area of ​​the main body 10 and the connecting part 20 helps to disperse the stress on the connecting part 20, improves the mechanical stability and reliability of the flexible circuit board 100, and helps to achieve a balance between dynamic and static performance, thereby enhancing the user experience. The main body 10 and the connecting part 20 can be manufactured or repaired separately. In the event of damage to the connecting part 20, only the connecting part 20 can be repaired or replaced, solving the problem that the connecting part 20 of the flexible circuit board 100 cannot be repaired. This helps to optimize the manufacturing process, reduce production costs, and improve production efficiency, providing technical support for the development of foldable display products.

[0101] In some embodiments, such as Figure 11As shown, the display panel 2 includes a display area AA and a peripheral area VA. A bending area and a bonding area are also included on one side of the display area AA. The display panel 2 includes a first part 201, a second part 202, and a third part 203. The first part 201 is used for display, the second part 202 is used for bonding, and the third part 203 is used for bending, thereby bending the second part 202 to the non-light-emitting side P2 of the first part 201.

[0102] like Figure 10 As shown, after bending, the second part 202 is electrically connected to the main body 10 of the flexible circuit board 100 and the driver chip 5 respectively. The flexible circuit board 100 is used to realize the electrical connection between the main board 3 and the display panel 2. The driver chip 5 provides signals to the display panel 2 to drive the display panel 2 to display the image.

[0103] For example, between the non-light-emitting side P2 of the first part 201 and the main body 10, the display device 200 further includes a support layer 61, an optical adhesive layer 62, and a back film (U-film) 63. The back film (U-film) 63 is disposed on the non-light-emitting side P2 of the first part 201, the optical adhesive layer 62 is disposed on the side of the back film (U-film) 63 away from the first part 201, and the support layer 61 is disposed on the side of the optical adhesive layer 62 away from the back film (U-film) 63.

[0104] The support layer 61 is usually provided with micro-aperture through holes to disperse stress during the bending process of the display panel 2, avoid stress concentration that could lead to creases, and improve the compression resistance and service life of the folding product.

[0105] The support layer 61, the optical adhesive layer 62, and the back film (U-film) 63 extend between the first part 201 and the second part 202 to provide support and prevent the third part 203 from bending and breaking.

[0106] Between the support layer 61 and the second part 202, a dielectric layer 64 and a back film (U-film) 63 are also provided, that is, the back film (U-film) 63 is also provided on the side of the second part 202 closer to the first part 201. Both the dielectric layer 64 and the back film (U-film) 63 can play a protective and supporting role, preventing the third part 203 from bending and breaking.

[0107] An organic material layer 65 can also be provided on the outer side of the bend of the third part 203 to protect the third part 203 from damage by external force or collision.

[0108] In some embodiments, such as Figure 10 As shown, after bending, a third pin 204 is provided on the surface of the second part 202 away from the first part 201, and the main body 10 is electrically connected to the third pin 204 through the first pin 13.

[0109] For example, a conductive layer 66 is also provided between the first pin 13 and the third pin 204. For example, the conductive layer 66 includes an anisotropic conductive film to achieve a good electrical connection between the first pin 13 and the third pin 204, thereby improving the reliability and durability of the connection.

[0110] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A flexible circuit board, characterized in that, include: The main body includes a plurality of first conductive layers and a plurality of first insulating layers, wherein the plurality of first conductive layers and the plurality of first insulating layers are alternately stacked; A first pin is provided on one side of at least one of the plurality of first conductive layers, and the first pin is configured to be electrically connected to the display panel; the main body also includes a first connection structure; The connecting portion includes multiple second conductive layers and multiple second insulating layers, which are alternately stacked. The connecting portion also includes a second connecting structure, one end of which is connected to the first connecting structure through the second connecting structure, and the other end is bent and configured to be connected to the motherboard.

2. The flexible circuit board according to claim 1, characterized in that, Along the direction in which the first conductive layer and the first insulating layer are alternately stacked, the first connection structure is disposed on the outermost side of the plurality of first conductive layers; Along the direction in which the second conductive layer and the second insulating layer are alternately stacked, the second connection structure is disposed on the outermost side of the plurality of second conductive layers.

3. The flexible circuit board according to claim 1, characterized in that, The material of at least one first conductive layer includes electrolytic copper, and the material of at least one second conductive layer includes rolled copper.

4. The flexible circuit board according to claim 1, characterized in that, The material of the multiple first conductive layers of the main body includes electrolytic copper; the material of the multiple second conductive layers of the connecting part includes rolled copper.

5. The flexible circuit board according to claim 1, characterized in that, Both the first connection structure and the second connection structure are solder pads.

6. The flexible circuit board according to claim 5, characterized in that, The shape of the orthographic projection of the first connecting structure onto the main body is one of a circle, an ellipse, or a semicircle; and / or, The shape of the orthographic projection of the second connecting structure onto the main body is one of a circle, an ellipse, or a semicircle.

7. The flexible circuit board according to claim 5, characterized in that, The surface of the first connecting structure is provided with a plating layer; and / or, The surface of the second connection structure is coated.

8. The flexible circuit board according to claim 1, characterized in that, The flexible circuit board further includes a buffer layer, which is disposed between the first connection structure and the second connection structure. The material of the buffer layer includes anisotropic conductive film or flexible polymer.

9. The flexible circuit board according to claim 1, characterized in that, The material of at least one first conductive layer includes electrolytic copper, and the material of at least one second conductive layer includes rolled copper; The flexible circuit board further includes a transition layer, which is disposed between the first connection structure and the second connection structure. The coefficient of thermal expansion of the transition layer is between that of the electrolytic copper and the rolled copper.

10. The flexible circuit board according to claim 1, characterized in that, The flexible circuit board further includes a heat dissipation structure, which encloses at least a portion of the first connection structure. And / or, the heat dissipation structure encloses at least a portion of the second connection structure.

11. The flexible circuit board according to claim 1, characterized in that, The surface of the main body is provided with a plurality of heat dissipation holes, which are arranged around the first connecting structure and penetrate at least one first conductive layer; and / or, The surface of the connecting part is provided with a plurality of heat dissipation holes, which are arranged around the second connecting structure and penetrate at least one second conductive layer.

12. The flexible circuit board according to claim 1, characterized in that, The flexible circuit board also includes a heat sink, one end of which is connected to the side surface of the main body near the first connecting structure, and the other end of which is connected to the side surface of the connecting part away from the second connecting structure.

13. The flexible circuit board according to claim 1, characterized in that, One of the first connection structure and the second connection structure is a board-to-board connector male socket, and the other is a board-to-board connector female socket, wherein the board-to-board connector male socket and the board-to-board connector female socket are fastened together.

14. The flexible circuit board according to claim 1, characterized in that, The first connection structure is a zero insertion force connector, and the second connection structure is a second pin, which is inserted into the zero insertion force connector.

15. A display device, characterized in that, Includes a display panel, a motherboard, and a flexible circuit board as described in any one of claims 1 to 14; The flexible circuit board is located on the non-light-emitting side of the display panel, and the main body of the flexible circuit board is electrically connected to the display panel, while the connecting part of the flexible circuit board is electrically connected to the motherboard.

16. The display device according to claim 15, characterized in that, The display panel includes a first part for display and a second part for bonding, wherein the second part is bent to the non-light-emitting side of the first part; The main body of the flexible circuit board is electrically connected to the second part.

17. The display device according to claim 16, characterized in that, A third pin is provided on the surface of the second part that is away from the first part; The main body is electrically connected to the third pin via the first pin.

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