Flexible circuit board, display panel, and display apparatus

Abstract

The present application relates to a flexible circuit board, a display panel, and a display apparatus. The flexible circuit board comprises: a substrate, an electronic element, and an adhesive layer. The substrate comprises a device region, the device region is located on an upper surface of the substrate, and the electronic element is fixed in the device region. The adhesive layer is fixed on a lower surface of the substrate. The adhesive layer comprises an adhesive portion and a cavity portion formed by hollowing out part of the adhesive portion, and the cavity portion is located below the device area. When the electronic element is fixed to the device area by means of surface mount technology, a concave-convex mark will be generated on the lower surface of the substrate, and the cavity portion is arranged below the device area in the present application, such that the concave-convex mark on the lower surface of the substrate can be prevented from being transferred to other film layers.

Description

Flexible circuit board, display panel and display device Technical Field

[0001] The present application relates to the field of display technology, and in particular to a flexible circuit board, a display panel, and a display device. Background Art

[0002] A flexible circuit board (FPC), also known as a flexible printed circuit board (FPCB), is a circuit board made of a flexible substrate. Compared to traditional rigid circuit boards, flexible circuit boards offer greater flexibility and bendability, allowing them to adapt to complex curves and confined spaces. Consequently, they are widely used in a variety of fields, including consumer electronics (such as smartphones and tablets), automotive electronics, medical equipment, and aerospace. They meet the demand for compact, lightweight, and multifunctional electronic devices, and demonstrate excellent performance and reliability in harsh environments such as high temperature, high humidity, and high vibration.

[0003] In display panels, surface mount technology (SMT) is often used to achieve electrical connections between flexible circuit boards (FPCBs) and electronic components. However, when electronic components are soldered to a thinner FPCB (e.g., a FPCB with fewer than three layers) using SMT, uneven stencils often appear in the soldering area of ​​the FPCB. These stencils can also be transmitted through the FPCB to other film layers of the display panel, affecting not only the aesthetics of the FPCB but also the performance of devices in the area where the FPCB is located.

[0004] Summary of the Invention

[0005] The present application provides a flexible circuit board, a display panel, and a display device to address deficiencies in related technologies.

[0006] According to a first aspect of an embodiment of the present application, a flexible circuit board is provided, comprising: a substrate, electronic components and an adhesive layer; the substrate comprises a device area, the device area is located on the upper surface of the substrate, and the electronic components are fixed in the device area; the adhesive layer is fixed to the lower surface of the substrate; the adhesive layer comprises an adhesive portion and a cavity portion formed by a hollowed-out portion of the adhesive portion, and the cavity portion is located below the device area.

[0007] Furthermore, the number of the device regions is consistent with the number of the cavity portions, and the cavity portions are arranged below the device regions in a one-to-one correspondence.

[0008] Furthermore, the area of ​​each cavity portion is greater than or equal to the area of ​​the corresponding device region.

[0009] Furthermore, the bonding part includes a first bonding part, a second bonding part and a third bonding part; the first bonding part and the second bonding part are respectively located on the left and right sides of the cavity part, and the third bonding part is located below the cavity part. The first bonding part, the second bonding part and the third bonding part surround a cavity to form the cavity part.

[0010] Furthermore, it also includes a grounding portion; a groove is provided on the lower surface of the substrate, and the grounding portion is provided in a cavity surrounded by the groove and is located above the adhesive layer.

[0011] Furthermore, it also includes a filling glue; there is a gap between the grounding portion and the adhesive layer, and the filling glue is arranged in the gap and fills the gap to electrically connect the grounding portion and the adhesive layer.

[0012] Furthermore, the area of ​​the grounding portion is larger than the area of ​​the filling glue.

[0013] Furthermore, the grounding portion is located above the bonding portion.

[0014] Furthermore, the grounding portion is located above the cavity portion.

[0015] Furthermore, it also includes an elastic conductive member; the elastic conductive member is arranged in the cavity portion and electrically connected to the filling glue.

[0016] Furthermore, the elastic conductive member includes a shell and a filling member; the shell is enclosed to form a cavity, and the filling member is arranged in the cavity; the shell is electrically connected to the filling glue.

[0017] Furthermore, the shell is conductive cloth, and the filling piece is foam.

[0018] Furthermore, the substrate is formed by stacking at least less than six layers of conductive base materials.

[0019] Furthermore, the base material is metallic copper, and the substrate has two layers.

[0020] According to a second aspect of the embodiments of the present application, a display panel is provided, comprising the above-mentioned flexible circuit board.

[0021] According to a third aspect of the embodiments of the present application, a display device is provided, comprising the above-mentioned display panel.

[0022] According to the above embodiments, by setting a cavity portion below the device area, it is possible to avoid the generation of convex and concave marks on the lower surface of the substrate when the electronic components are fixed to the device area through surface mounting technology, thereby transferring the convex and concave marks on the lower surface of the substrate to other film layers, thereby improving the aesthetics of the product.

[0023] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0025] FIG1 is a front schematic diagram of a flexible circuit board according to an embodiment of the present application.

[0026] FIG. 2 is a schematic diagram of the back side of the flexible circuit board shown in FIG. 1 .

[0027] FIG3 is a schematic cross-sectional view of the flexible circuit board shown in FIG2 .

[0028] FIG. 4 is a schematic diagram of another embodiment of the flexible circuit board shown in FIG. 3 .

[0029] FIG. 5 is a cross-sectional view of the ground portion of the flexible printed circuit board shown in FIG. 3 .

[0030] FIG. 6 is a schematic back view of another embodiment of the flexible circuit board shown in FIG. 1 .

[0031] FIG. 7 is a schematic cross-sectional view of the flexible circuit board shown in FIG. 6 .

[0032] FIG8 is a cross-sectional view of the ground portion of the flexible printed circuit board shown in FIG7.

[0033] Explanation of the accompanying drawings: 10. Substrate; 11. Device area; 20. Electronic component; 30. Adhesive layer; 31. Adhesive portion; 311. First adhesive portion; 312. Second adhesive portion; 313. Third adhesive portion; 32. Cavity portion; 40. Grounding portion; 50. Filling glue; 60. Elastic conductive member; 61. Shell; 62. Filling member; 70. Solder pin; 80. Board-to-board connector; 81. Head; 82. Seat; 90. SCF layer. DETAILED DESCRIPTION

[0034] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0035] Referring to Figures 1 to 3, the present application provides a flexible circuit board, which may include: a substrate 10, an electronic component 20 and an adhesive layer 30. The substrate 10 may include a device area 11, and the device area 11 may be located on the upper surface of the substrate 10, and the electronic component 20 is fixed in the device area 11. Generally, the electronic component 20 is mounted in the device area 11 by surface mount technology (SMT), and the electronic component 20 is a basic component of electronic equipment and circuits. In the present application, the electronic component 20 may include resistors for controlling current, dividing voltage, and matching impedance, capacitors for storing charge and releasing energy, inductors for storing magnetic energy and resisting current changes, integrated circuits integrating multiple electronic components, etc.

[0036] The adhesive layer 30 can be fixed to or disposed on the lower surface of the substrate 10. The adhesive layer 30 can be a conductive adhesive, and the area of ​​the adhesive layer 30 is less than or equal to the area of ​​the substrate 10. This ensures that the substrate 10 is not easily detached when bonded to other film layers via the adhesive layer 30, thereby improving the bonding strength. In this application, a conductive adhesive is an adhesive with conductive properties, commonly used in applications such as connecting electronic devices, conductive filling, and shielding.

[0037] The conductive adhesives used in the embodiments of the present application include silver paste conductive adhesives composed of silver particles suspended in an adhesive base with high conductivity and current carrying capacity, carbon paste conductive adhesives composed of carbon particles suspended in an adhesive base, which have inferior conductivity to silver paste but are more economical and are commonly used for low-cost circuit connection and conductive filling, adhesive tapes made of special conductive materials that can provide current conduction paths and are commonly used for connecting flexible circuits, conductive wiring, etc., conductive adhesives made by mixing conductive materials (such as carbon fibers, metal particles, etc.) with adhesives, which are commonly used for circuit connection, repairing conductive paths, etc., and copper paste conductive adhesives composed of copper particles suspended in an adhesive base, which have good conductivity and current carrying capacity and are commonly used for connection, conductive filling, etc.

[0038] The adhesive layer 30 may include an adhesive portion 31 and a cavity portion 32 formed by hollowing out part of the adhesive portion 31. The cavity portion 32 is located below the device area 11. The "cavity portion 32 is located below the device area 11" mentioned here may include multiple situations: Scenario 1, the area corresponding to the cavity portion 32 completely covers the area corresponding to the device area 11, that is, the projection of the device area 11 in the vertical direction completely falls within the projection of the cavity portion 32 in the vertical direction, or the projection of the device area 11 in the vertical direction is completely consistent with the projection of the cavity portion 32 in the vertical direction; Scenario 2, the area corresponding to the cavity portion 32 partially overlaps with the area corresponding to the device area 11, that is, a portion of the projection of the device area 11 in the vertical direction falls within the projection of the cavity portion 32 in the vertical direction.

[0039] When electronic component 20 is attached to device area 11 using surface mount technology, the lower surface of substrate 10 develops irregularities, as shown in Figure 3. In conventional flexible circuit boards, these irregularities transmit significant deformation to adhesive layer 30, significantly impacting the smoothness of the flexible circuit board's bonding interface. Furthermore, these irregularities can be transmitted through substrate 10 and adhesive layer 30 to the underlying films or components of the flexible circuit board. If these underlying films or components are sensitive to external forces, they are more likely to be damaged by these irregularities.

[0040] These bumps and grooves are produced when the electronic component 20 is fixed to the device area 11 using SMT technology. The bumps and grooves are mainly located on the lower surface of the substrate 10, directly below the device area 11. Therefore, by removing the solid portion of the adhesive layer 30 below the device area 11 to form a cavity 32, the bumps and grooves will not be transmitted to other film layers connected to the adhesive layer 30, thereby avoiding affecting the aesthetics of the flexible circuit board and the morphology of the underlying film layers. At the same time, the area where the device area 11 is located generally accounts for a relatively small proportion of the area on the substrate 10. Therefore, removing the area of ​​the adhesive layer 30 directly below the device area 11 will not affect the bonding strength of the flexible circuit board when it is bonded to other film layers.

[0041] The substrate 10 in the embodiment of the present application can be formed by stacking fewer than six layers of conductive substrate. Conventional flexible circuit boards typically utilize six layers of conductive substrate, resulting in superior overall strength and minimal concave and convex marks when the electronic components 20 are secured to the device area 11 via SMT technology. However, the resulting six-layer stack is relatively thick, hindering the development of thinner and lighter flexible circuit boards. Furthermore, the high number of stacked conductive substrate layers results in higher material and processing costs, hindering scalable production.

[0042] Therefore, preferably, in one embodiment shown in the present application, the substrate 10 has two layers, and is formed by stacking metal copper as a base material. The base material of the flexible circuit board in the embodiment of the present application can be formed by a flexible polymer material with a conductive metal embedded therein. The flexible polymer material is as follows:

[0043] Polyester Film: Polyester substrate has high mechanical and electrical properties and is suitable for some low-cost, medium- and low-density wiring applications;

[0044] Polyamide Film: Polyamide substrate has good high temperature resistance and mechanical strength, and is suitable for applications in some high temperature environments;

[0045] Polytetrafluoroethylene Film (PTFE): PTFE substrate has excellent high temperature resistance, chemical stability, and electrical insulation properties, and is suitable for applications requiring extremely high reliability and special environments.

[0046] Polyether Ketone Film (PEEK): PEEK substrate has high heat resistance, mechanical strength and chemical stability, and is suitable for applications in some high temperature and high pressure environments.

[0047] The above are only some common substrate types. The embodiments shown in this application are not limited to the above substrates, and may also be other substrates not listed that are suitable for manufacturing the flexible circuit board substrate 10.

[0048] In the embodiment of the present application, the base material of the substrate 10 can be composed of the following base layers in sequence: polyester film (Polyester Film), as the flexible base material of the flexible circuit board substrate 10, polyester film has good mechanical and electrical properties, can provide the ability to resist bending and stretching, and also has certain insulation properties; copper foil (Copper Foil): copper foil is a conductive layer, located on the surface of the polyester film, and can provide the flexible circuit board substrate 10 with the conductive function required for circuit wiring. Usually, there will be one or more layers of copper foil on the flexible circuit board substrate 10 for transmitting signals, power supply and ground wires, etc.; coverlay is a protective layer covering the surface of the copper foil, usually made of polyester film or polyamide film, which can provide additional mechanical protection and insulation properties to prevent the copper foil layer from being damaged.

[0049] The above is only one of the embodiments of the substrate 10 shown in the embodiment of the present application. Other materials with the same properties can also be used as substitutes to form the material of the substrate 10 shown in the embodiment of the present application.

[0050] Generally, multiple device areas 11 can be provided on the substrate 10. In order to ensure that the uneven marks generated when all electronic components 20 are fixed to the device area 11 through SMT technology will not affect the adhesion of the flexible circuit board to other film layers, the number of device areas 11 is consistent with the number of cavity portions 32, and the cavity portions 32 are provided one-to-one below the device area 11, and the area of ​​each cavity portion 32 can be greater than or equal to the area of ​​the corresponding device area 11.

[0051] 4 , in one embodiment, the adhesive portion 31 includes a first adhesive portion 311, a second adhesive portion 312, and a third adhesive portion 313. The first adhesive portion 311 and the second adhesive portion 312 are located on opposite left and right sides of the cavity portion 32, respectively, and the third adhesive portion 313 is located below the cavity portion 32. The first adhesive portion 311, the second adhesive portion 312, and the third adhesive portion 313 form a cavity to form the cavity portion 32.

[0052] To ensure that the uneven marks generated when all electronic components 20 are fixed to the device area 11 by SMT technology will not affect the adhesion of the flexible circuit board to other film layers, in this embodiment, the thickness of the cavity portion 32 should be greater than the thickness of all the uneven marks.

[0053] 5 , the flexible circuit board provided in this application further includes a grounding portion 40 . A groove is provided on the lower surface of the substrate 10 , and the grounding portion 40 is disposed in a cavity surrounded by the groove and located above the adhesive layer 30 .

[0054] Grounding is a common method in electronic equipment and circuits. It can provide safety protection for flexible circuit boards and electronic components 20 arranged thereon, and safely release dangerous charges such as static charges or leakage that may accumulate in the equipment to the ground, avoiding the risk of electric shock or fire to the human body; it can help suppress electromagnetic interference. Since electronic equipment will generate a certain amount of electromagnetic radiation when working, it will also be affected by electromagnetic interference from the external environment. Through effective grounding design, these electromagnetic radiation and interference can be guided to the ground, reducing the impact on other equipment and systems; grounding helps to improve the stability and performance of the circuit. Through grounding, a stable reference potential can be formed to reduce interference and instability between signal interfaces; grounding can prevent the accumulation and release of static electricity. Static electricity is a common phenomenon when electronic equipment and the human body come into contact or rub against each other. It may cause circuit damage or data loss. Through a good grounding design, static charges can be safely guided to the ground, reducing the impact on equipment and circuits.

[0055] In the embodiment shown in the present application, a polyester film is covered on the copper foil to form the base material of the substrate 10 in the embodiment of the present application. The polyester film has insulating properties. Therefore, in order to allow the substrate 10 to be grounded, the grounding portion 40 is formed by removing the polyester film from the surface of the substrate 10 by chemical etching or mechanical means, thereby exposing the copper foil.

[0056] Since the polyester film is removed from the surface of the substrate 10 by chemical etching or mechanical means to form a groove, the grounding portion 40 is located in the groove, and there is a gap between the grounding portion 40 and the adhesive layer 30. Due to the existence of the gap, the grounding portion 40 cannot be electrically connected to the adhesive layer 30 and thus cannot be grounded.

[0057] Therefore, the flexible circuit board provided herein also includes a filler 50. The filler 50 is disposed within the gap and fills the gap to electrically connect the ground portion 40 and the adhesive layer 30. Generally, the area of ​​the ground portion 40 is larger than the area of ​​the filler 50. The filler 50 is a conductive filler that fills the gap.

[0058] Gap-filling conductive adhesive is an adhesive used to repair or create conductive connections. It typically consists of a conductive filler (such as silver, copper, or carbon nanotubes) and an adhesive matrix. Gap-filling conductive adhesive is widely used in the electronics field to repair broken wires on circuit boards, repair conductive traces on touch screens, and create conductive connections between electronic components. The primary function of gap-filling conductive adhesive is to provide excellent conductivity and bonding properties. When a wire breaks on a flexible circuit board, gap-filling conductive adhesive can be used to fill the gap and restore circuit connectivity. This adhesive has high conductivity, effectively transferring current and forming a reliable conductive path. Gap-filling conductive adhesive can also be used to repair conductive traces on touch screens. By applying gap-filling conductive adhesive to a broken conductive trace, the circuit connection can be reestablished, allowing the touch screen to function properly again. Furthermore, gap-filling conductive adhesive can be used to create conductive connections between electronic devices. For example, during the assembly of electronic components, if a reliable conductive connection between two components is required, gap-filling conductive adhesive can be used to bond and facilitate current flow.

[0059] The choice of gap-filling conductive adhesive should be determined based on the specific application requirements. Different gap-filling conductive adhesives have varying conductivity, bonding properties, and durability. Therefore, before use, it is important to carefully select the appropriate gap-filling conductive adhesive for your specific application and follow the manufacturer's instructions for proper application.

[0060] In this embodiment, the filling glue 50 and the adhesive layer 30 can be the same conductive glue or different conductive glues. The type of conductive glue used as the filling glue 50 has been described in the adhesive layer 30 and will not be repeated here.

[0061] The flexible printed circuit board may further include a shielding layer 90. The shielding layer 90 may be an SCF layer (Shield Copper Foil). The shielding layer 90 is located below and connected to the adhesive layer 30. The SCF layer is a specially treated copper foil applied to a flexible printed circuit board (FPC) or a rigid printed circuit board.

[0062] Shielding layer 90 has the following main features and uses:

[0063] The shielding layer 90 can provide electromagnetic shielding protection to prevent external electromagnetic signals from interfering with the circuit, thereby ensuring the stability and reliability of the circuit; due to the good conductivity of copper, the shielding layer 90 can be used to provide a current conduction path to ensure the normal operation of the circuit; the shielding layer 90 is usually very thin and can adapt to the compact design of the circuit board without taking up too much space; the shielding layer 90 can be combined with other circuit layers (such as signal layers, power layers, etc.) to achieve high integration and compact layout of the circuit.

[0064] The preparation of the shielding layer 90 generally includes the following key steps:

[0065] Copper foil selection: Choose high-purity copper foil as raw material to ensure good conductivity and reliability;

[0066] Surface treatment: Special treatment of the copper foil surface, such as chemical treatment, mechanical polishing, etc., to improve its surface smoothness and adhesion;

[0067] Preparation process: The shielding layer 90 is combined with the plate material of the flexible circuit board substrate 10 through shielding copper plating, bonding, lamination and other processes. In the embodiment shown in this application, the shielding layer 90 is connected to the adhesive layer 30.

[0068] The shielding layer 90 is widely used in electronic products in various fields, such as communication equipment, consumer electronics, automotive electronics, etc. It can effectively reduce electromagnetic interference, improve the stability and performance of the circuit, and ensure the normal operation of the equipment.

[0069] 1 to 5 , the grounding portion 40 is located above the bonding portion 31 . The grounding portion 40 is electrically connected to the bonding portion 31 via a filler 50 .

[0070] Referring to Figures 6 to 8 , in another embodiment, the grounding portion 40 is located above the cavity 32. Due to the presence of the cavity 32, the grounding portion 40 cannot be connected to the adhesive portion 31 via the filler 50. Therefore, the flexible printed circuit board further includes an elastic conductive member 60 disposed within the cavity 32 and electrically connected to the filler 50 and the shielding layer 90.

[0071] In one embodiment, the elastic conductive member 60 may include a housing 61 and a filler 62. The housing 61 encloses a cavity, and the filler 62 is disposed within the cavity. The housing 61 is electrically connected to the filler 50, allowing current to flow from the ground portion 40 through the filler 50 and the housing 61 to the shielding layer 90.

[0072] In order to ensure that the uneven marks generated when the electronic component 20 is fixed to the device area 11 through SMT technology will not affect the adhesion of the flexible circuit board to other film layers, in this embodiment, the shell 61 is conductive cloth and the filler 62 is foam. The foam has a compressible property. Therefore, the uneven marks are transmitted through the foam that is squeezed as the filler 62 in contact with the shell 61. The foam is deformed by the action of force, thereby avoiding the uneven marks from being transmitted to the shielding layer 90.

[0073] Conductive fabric is a material used for electromagnetic shielding, with excellent conductivity and anti-interference performance. Depending on the application scenario and requirements, conductive fabric can use different materials and manufacturing processes.

[0074] The following are some common conductive fabrics:

[0075] Silver fiber conductive fabric: Silver fiber conductive fabric uses fiber materials as a carrier, with silver fiber as the key conductive component. Silver fiber conductive fabric has excellent conductivity and anti-interference properties, suitable for electromagnetic shielding in high-frequency and microwave fields.

[0076] Copper Foil Conductive Fabric: Copper foil is used as a carrier material and can be braided with steel or copper wire to enhance its mechanical properties. Copper foil conductive fabric has excellent conductivity and oxidation resistance, and is suitable for electromagnetic shielding in low and medium frequency fields.

[0077] Conductive Coated Fabric: Conductive coated fabric is a base fabric coated with a conductive material (such as copper or silver). The coating thickness and method can be varied depending on the application. Conductive coated fabric offers excellent conductivity and shear resistance, making it suitable for electromagnetic shielding applications in complex shapes.

[0078] Carbon fiber conductive fabric: Carbon fiber conductive fabric uses carbon fiber as a carrier, offering lightweight, high strength, and excellent conductivity. Carbon fiber conductive fabric is suitable for electromagnetic shielding in harsh environments such as high temperature and high humidity, such as those in the aerospace, automotive, and other fields.

[0079] Foam is a common polymer material with sound absorption, sound insulation, and shockproof properties. It is widely used in packaging, sound insulation, shock absorption, protection, and other fields. The following are several common types of foam:

[0080] Polyethylene (PE) foam: A lightweight, soft foam material, PE foam offers excellent sound absorption, sound insulation, and shock absorption properties, while also possessing a certain degree of flexibility and elasticity. It is commonly used in electronic product packaging, logistics protection, and other fields.

[0081] Polyurethane (PU) foam: PU foam is a high-density, wear-resistant, and pressure-resistant foam material with excellent shock absorption and durability. It is commonly used in machinery, automotive interiors, sports equipment, and other fields.

[0082] Polystyrene (EPS) foam: Also known as expanded polystyrene (EPS), polystyrene foam is a lightweight, fluffy foam material with excellent energy absorption and thermal insulation properties. It is commonly used in building insulation, packaging filling materials, and other fields.

[0083] Polyester (PET) foam: Polyester foam is a high-density foam material that offers excellent pressure resistance and durability, as well as excellent moisture absorption. Polyester foam is commonly used in electronics packaging and medical device protection.

[0084] In the embodiments shown in this application, the conductive cloth and foam can be selected from any one of the above-mentioned ones and their combinations. This application does not impose any restrictions on this. It only requires that the selected conductive cloth material has conductive properties and the foam material has the property of being able to undergo elastic deformation.

[0085] The flexible circuit board in the embodiment shown in this application further includes bonding pins 70 and a board-to-board (BTB) connector.

[0086] The soldering pins 70 are metal wires used to connect the chip pins with the package base pins during the semiconductor chip (such as integrated circuit) packaging process. They play an important role in electrically connecting the chip to the package base.

[0087] During the semiconductor packaging process, the chip's circuit pins need to be reliably connected to the package base pins to achieve signal transmission and power supply. This requires the use of solder wires to connect the chip pins to the package base pins. Solder wires are typically made of metal materials such as copper or aluminum.

[0088] The solder wires are connected to the chip pins and package base pins through a series of process steps. The typical process includes the following steps:

[0089] Arrange pins: Align the chip with the package base correctly and ensure the matching of the pins.

[0090] Soldering: Using solder or other welding materials, a metal connection is formed between the chip pins and the package base pins. This can be done by methods such as heat pressure welding, ultrasonic welding, and laser welding.

[0091] Crimp or Ball Restraint: In some package types, the solder leads may need to be further secured by crimping or forming solder balls.

[0092] Cutting: Cut the soldering leads to the appropriate length.

[0093] In the embodiment shown in this application, the soldering pins 70 are primarily used to connect the electronic components 20 and the wires. They provide a reliable contact point on the flexible printed circuit board to achieve electrical connection. The soldering pins 70 are generally used for the following main functions:

[0094] Connecting Electronic Components 20: Solder pins 70 provide a fixed location for electronic components 20 (such as resistors, capacitors, and chips), electrically connecting them to the flexible printed circuit board through soldering. Solder pins 70 are positioned with a defined width and spacing on the board to facilitate soldering and ensure soldering quality.

[0095] Conducting Electrical Signals: Solder pins 70 conduct electrical signals from electronic components 20 to other circuit paths on the flexible printed circuit board through soldering, thereby achieving signal transmission. The conductivity of solder pins 70 determines the stability and reliability of the circuit.

[0096] Providing Mechanical Support: Solder pins 70 also provide mechanical support for electronic component 20, keeping it securely fixed to the flexible circuit board. This is particularly important for flexible circuit boards, which require a certain degree of flexibility and bending resistance. The presence of solder pins 70 can increase the strength and stability of the connection between electronic component 20 and the flexible circuit board.

[0097] Heat conduction and heat dissipation: The solder pins 70 can also act as a heat sink when needed, transferring heat generated by the components to the flexible circuit board for heat dissipation. This is especially important for high-power components, as it helps maintain the normal operating temperature of the components.

[0098] In short, solder wires are metal pins used to connect the chip pins to the package base pins during the semiconductor chip packaging process, playing a vital role in electrical connection and signal transmission. Polyvinyl chloride (PVC) foam: PVC foam is a rigid, durable foam material with excellent water and chemical resistance. PVC foam is commonly used in building sound insulation, floor shock absorption pads, and other fields.

[0099] A board-to-board connector is a device used to electrically and mechanically connect two or more circuit boards. It typically consists of a header and a socket. The header and socket are attached to separate circuit boards and interconnected through a design of pins and slots.

[0100] Board-to-board connectors are typically compact in design and have a large number of pins, providing high interface density and suitable for applications requiring multiple signal transmission.

[0101] Board-to-board connectors provide reliable mechanical fixation during the connection process, ensuring the stability and reliability of the connection and are suitable for a variety of industrial and consumer electronic devices.

[0102] Board-to-board connectors transmit signals through pin and slot designs, provide good electrical connections, and can transmit high-frequency, high-speed, or other complex signals to meet the needs of different applications.

[0103] Board-to-board connectors usually offer a variety of specifications and models, including the number of pins, arrangement, connection method, etc., which can be selected and customized according to specific application requirements.

[0104] In this embodiment, the solder pins 70 are located on one side of the substrate 10 and connected to the substrate 10. The board-to-board connector 80 includes a seat 82 and a head 81 extending from the seat 82. The seat 82 is connected to the substrate 10.

[0105] An embodiment of the present application further provides a display panel, comprising a display module and the flexible circuit board described in any of the above embodiments.

[0106] An embodiment of the present application further provides a display device, comprising the above-mentioned display panel.

[0107] It should be noted that the display device in this embodiment can be any product or component with a display function, such as electronic paper, a mobile phone, a tablet computer, a television, a laptop computer, a digital photo frame, or a navigator.

[0108] It should be noted that in the accompanying drawings, the sizes of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when an element or layer is referred to as being "on" another element or layer, it may be directly on the other element, or there may be an intermediate layer. In addition, it will be understood that when an element or layer is referred to as being "under" another element or layer, it may be directly under the other element, or there may be more than one intermediate layer or element. In addition, it will also be understood that when a layer or element is referred to as being "between" two layers or elements, it may be the only layer between the two layers or elements, or there may also be more than one intermediate layer or element. Similar reference numerals throughout the text indicate similar elements.

[0109] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

[0110] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0111] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A flexible circuit board, characterized in that: The flexible circuit board includes: a substrate, electronic components and an adhesive layer; the substrate includes a device area, the device area is located on the upper surface of the substrate, and the electronic components are fixed to the device area; the adhesive layer is fixed to the lower surface of the substrate; the adhesive layer includes an adhesive portion and a cavity portion adjacent to the adhesive portion, and the cavity portion is located below the device area.

2. The flexible circuit board according to claim 1, characterized in that: The number of the device regions is the same as the number of the cavity portions, and the cavity portions are arranged below the device regions in a one-to-one correspondence.

3. The flexible circuit board according to claim 2, characterized in that: The area of ​​each of the cavity portions is greater than or equal to the area of ​​the device region corresponding thereto.

4. The flexible circuit board according to claim 3, characterized in that: The bonding part includes a first bonding part, a second bonding part and a third bonding part; the first bonding part and the second bonding part are respectively located on the left and right sides of the cavity part, and the third bonding part is located below the cavity part; the first bonding part, the second bonding part and the third bonding part surround a cavity to form the cavity part.

5. The flexible circuit board according to claim 1, characterized in that: It also includes a grounding portion; a groove is arranged on the lower surface of the substrate, and the grounding portion is arranged in a cavity surrounded by the groove and is located above the adhesive layer.

6. The flexible circuit board according to claim 5, characterized in that: It also includes a filling glue; there is a gap between the grounding portion and the adhesive layer, and the filling glue is arranged in the gap and fills the gap to electrically connect the grounding portion and the adhesive layer.

7. The flexible circuit board according to claim 6, characterized in that: The area of ​​the grounding portion is greater than the area of ​​the filling glue.

8. The flexible circuit board according to claim 6, characterized in that: The grounding portion is located above the bonding portion.

9. The flexible circuit board according to claim 6, characterized in that: The grounding portion is located above the cavity portion.

10. The flexible circuit board according to claim 9, characterized in that: It also includes an elastic conductive member; the elastic conductive member is disposed in the cavity and electrically connected to the filling glue.

11. The flexible circuit board according to claim 10, characterized in that: The elastic conductive member includes a shell and a filling member; the shell is surrounded by a cavity, and the filling member is arranged in the cavity; the shell is electrically connected to the filling glue.

12. The flexible circuit board according to claim 11, characterized in that: The shell is conductive cloth, and the filler is foam.

13. The flexible circuit board according to any one of claims 1 to 12, characterized in that: The substrate is formed by stacking less than six layers of conductive substrates; the conductive substrate is metal copper, and the substrate has two layers.

14. A display panel, characterized in that: It comprises the flexible circuit board as claimed in any one of claims 1 to 13.

15. A display device, characterized in that: Comprising the display panel as claimed in claim 14.

Images