Circuit board assembly and electronic equipment

Abstract

The present application relates to a circuit board assembly and an electronic device, wherein the circuit board assembly includes a printed circuit board and a flexible circuit board fixed by welding, and the printed circuit board is provided with a first solder pad. Along the thickness direction of the flexible circuit board, a second solder pad is provided on at least one side surface of the flexible circuit board, and the second solder pad is connected to the first solder pad by metal wire bonding. The second solder pad is bonded to the first solder pad, and the second solder pad does not need to be provided with a through-hole structure, which can reduce the number of openings on the flexible circuit board, not only improving the structural strength of the flexible circuit board, but also improving the wiring density of the flexible circuit board and the number of solder pads on the flexible circuit board, thereby improving the flow capacity of the flexible circuit board, forming a multi-channel flow between the printed circuit board and the flexible circuit board, increasing the path current and achieving a cooling effect, so as to improve the service life of the components in the circuit board assembly, and thus helping to improve the service life of the electronic device.

Description

Technical Field

[0001] The present application relates to the technical field of terminal equipment, and in particular to a circuit board assembly and an electronic device. Background Art

[0002] Electronic devices (such as smartwatches, mobile phones, and laptops) typically incorporate printed circuit boards (PCBs) and flexible printed circuits (FPCs). Currently, FOB soldering (FPC on board) is used to connect PCBs and FPCs, replacing board-to-board (BTB) connectors, to achieve miniaturization. However, this connection method requires through-holes in the FPC, reducing the FPC's wiring density and impacting its current-carrying capacity. Summary of the Invention

[0003] The purpose of the embodiments of the present application is to provide a circuit board assembly and an electronic device to solve the problem of insufficient current flow capacity of the flexible circuit board due to too low wiring density in the above-mentioned related art.

[0004] In a first aspect, embodiments of the present application provide a circuit board assembly comprising a printed circuit board (PCB) and a flexible circuit board (FPCB). The PCB is provided with a first solder pad, and the FPCB is welded to the PCB. A second solder pad is provided on at least one surface of the FPCB along the thickness of the FPCB, and the second solder pad is connected to the first solder pad via a metal wire bond. In this embodiment, the second solder pad does not require a through-hole structure, which reduces the number of openings in the FPCB. This not only improves the structural strength of the FPCB, but also increases the wiring density and the number of solder pads on the FPCB, thereby increasing the current flow capacity of the FPCB. This creates a multi-channel flow path between the PCB and the FPCB, increasing the current flow and thus achieving a cooling effect.

[0005] In one possible embodiment, the printed circuit board is provided with a first receiving groove, and the flexible circuit board is soldered to the bottom wall of the first receiving groove. The flexible circuit board in this embodiment can be accommodated within the printed circuit board, making the circuit board assembly more compact and reducing the overall thickness of the circuit board assembly.

[0006] In a possible implementation manner, the first pad is disposed on the bottom wall of the first receiving groove. In this embodiment, all the metal leads are also located in the first receiving groove, making the structure of the circuit board assembly more compact.

[0007] In one possible embodiment, a second receiving groove is provided on the bottom wall of the first receiving groove. The circuit board assembly further includes a chip, at least a portion of which is located in the second receiving groove. Along the thickness direction of the flexible circuit board, the side surface of the flexible circuit board facing the second receiving groove is soldered and fixed to the chip. Along the thickness direction of the flexible circuit board, the second solder pad is provided on the side surface of the flexible circuit board away from the second receiving groove. The flexible circuit board in this embodiment can achieve double-sided fabrication, thereby improving the fabrication capacity of the flexible circuit board. Moreover, by providing the second receiving groove in the first receiving groove, the overall thickness of the circuit board assembly can be reduced.

[0008] In one possible embodiment, the circuit board assembly further includes an encapsulation structure, which is filled in the first receiving groove. In this embodiment, the encapsulation structure can improve the mechanical strength of the circuit board assembly, and when the encapsulation structure is filled in the first receiving groove, it does not increase the thickness of the circuit board assembly.

[0009] In one possible embodiment, the first solder pad is disposed on a side surface of the printed circuit board having the first receiving groove, along the thickness direction of the printed circuit board. In this embodiment, the first solder pad is located outside the first receiving groove, meaning that the first receiving groove is only used to accommodate the flexible circuit board. This helps reduce the size of the first receiving groove, mitigates the impact of the groove on the printed circuit board, and thereby improves the structural strength of the printed circuit board.

[0010] In one possible implementation, the circuit board assembly further includes an encapsulation structure secured to a surface of the printed circuit board having the first receiving groove. The first solder pad is located within the encapsulation structure. In this embodiment, the encapsulation structure can encapsulate the connection between the printed circuit board and the flexible circuit board, protecting the connection between the printed circuit board and the flexible circuit board from environmental influences, thereby improving the mechanical strength of the circuit board assembly and ensuring the reliability and stability of the circuit board assembly in various environments.

[0011] In one possible embodiment, the circuit board assembly further includes a chip. Along the thickness direction of the flexible circuit board, the flexible circuit board is soldered to the chip on a side thereof facing the printed circuit board. Along the thickness direction of the flexible circuit board, the second solder pad is disposed on a side thereof facing away from the printed circuit board. The flexible circuit board in this embodiment enables double-sided fabrication, thereby improving the fabrication capability of the flexible circuit board.

[0012] In one possible embodiment, the circuit board assembly further includes a reinforcement frame secured to a surface of the flexible circuit board, distal from the chip, along the thickness of the flexible circuit board. The reinforcement frame defines a first accommodating space, within which the second solder pad is located. In this embodiment, the reinforcement frame not only enhances the mechanical strength of the flexible circuit board, but also supports the flexible circuit board from the periphery of the second solder pad to maintain its flatness, thereby improving its structural stability.

[0013] In one possible embodiment, the printed circuit board is provided with a third receiving groove, and at least a portion of the chip is received within the third receiving groove. Along the thickness direction of the printed circuit board, the flexible circuit board is soldered to the side surface of the printed circuit board having the third receiving groove, and the first solder pad is provided on the side surface of the printed circuit board having the third receiving groove. In this embodiment, at least a portion of the chip can be located within the third receiving groove, making the circuit board assembly more compact and reducing the overall thickness of the circuit board assembly.

[0014] In one possible implementation, the circuit board assembly further includes an electronic component, which is soldered to the second solder pad. This embodiment achieves double-sided fabrication of the flexible circuit board, increasing the fabrication density of the flexible circuit board. Furthermore, it can shorten the connection path between the electronic component and the flexible circuit board, thereby improving the structural compactness of the circuit board assembly.

[0015] In one possible implementation, the circuit board assembly further includes an encapsulation structure secured to a surface of the printed circuit board having the third receiving groove, with the first solder pad, the second solder pad, and the electronic component located within the encapsulation structure. In this embodiment, the encapsulation structure protects the circuit board assembly, improving its mechanical strength and ensuring its reliability and stability in various environments.

[0016] In one possible embodiment, the printed circuit board includes a main body and a connecting plate. Along the thickness of the connecting plate, one side of the connecting plate is welded to the main body, and the other side of the connecting plate is welded to the connecting plate. Along the thickness of the connecting plate, the first solder pad is disposed on a side of the connecting plate facing away from the main body. In this embodiment, one side of the connecting plate is used to form an electrical connection with the main body, and the other side is used to form an electrical connection with the flexible printed circuit board, thereby achieving electrical continuity between the printed circuit board and the flexible printed circuit board.

[0017] In one possible embodiment, the circuit board assembly further includes a reinforcing member fixedly connected to the surface of the flexible circuit board on which the chip is mounted, along the thickness of the flexible circuit board. The reinforcing member is disposed circumferentially around the chip. In this embodiment, the reinforcing member serves to reduce the risk of damage to the portion of the flexible circuit board connecting the chip due to bending, thereby improving the stability and reliability of the chip's installation on the flexible circuit board.

[0018] In one possible embodiment, the circuit board assembly further includes a packaging structure, the packaging structure including a first sub-packaging structure and a second sub-packaging structure, the first sub-packaging structure being fixed to a side surface of the connecting plate having the first solder pad, the first solder pad and the second solder pad being located within the first sub-packaging structure, a second accommodation space being formed between the chip, the connecting plate, and the main body, and the second sub-packaging structure being filled within the second accommodation space. The first sub-packaging structure is used to encapsulate the connection between the printed circuit board and the flexible circuit board, protecting the connection between the printed circuit board and the flexible circuit board from the external environment and reducing the risk of physical damage or environmental corrosion to the connection between the printed circuit board and the flexible circuit board. The second sub-packaging structure is filled within the second accommodation space, and the second sub-packaging structure is used to implement chip packaging and improve the stability and reliability of the connection between the chip and the flexible circuit board.

[0019] In one possible implementation, the flexible circuit board includes a plurality of second solder pads arranged in an array. Along the width of the second solder pads, the distance between the centerline of any second solder pad and the centerline of another adjacent second solder pad is 0.1 mm to 3.0 mm. This embodiment enables a fine-pitch arrangement of the second solder pads, which helps increase the number and wiring density of the second solder pads in the flexible circuit board.

[0020] In one possible implementation, the printed circuit board further includes a third pad, and the flexible circuit board further includes a fourth pad. The fourth pad is secured to the third pad via a solder joint. The fourth pad includes a through-hole extending through the thickness of the flexible circuit board, with at least a portion of the solder joint located within the through-hole. In this embodiment, the third and fourth pads are connected using welding technology. The solder joint can securely connect to and establish electrical continuity with the metal connection layer within the through-hole, thereby securing the third and fourth pads via soldering and establishing an electrical connection.

[0021] In one possible embodiment, the flexible circuit board includes a plurality of second solder pads, the plurality of second solder pads being distributed in an array, the array having a first side and a second side disposed oppositely along the width direction of the flexible circuit board, and a third side and a fourth side disposed oppositely along the length direction of the flexible circuit board, and the fourth solder pads being provided on at least two of the first side, the second side, the third side, and the fourth side. In this embodiment, the fourth solder pads are provided on at least two of the first side, the second side, the third side, and the fourth side to enhance the stability of the solder connection between the flexible circuit board and the printed circuit board. If the fourth solder pads are provided on only one of the first side, the second side, the third side, and the fourth side, the flexible circuit board may be susceptible to movement or misalignment during actual use, thereby shortening the service life of the circuit board assembly.

[0022] In a second aspect, an embodiment of the present application provides an electronic device including the circuit board assembly described in the above embodiments. This embodiment is conducive to miniaturization and thinness of the electronic device, thereby helping to increase the service life of the electronic device.

[0023] In one possible embodiment, the printed circuit board is a mainboard, the electronic device further includes a camera module, and the end of the flexible circuit board away from the mainboard is connected to the camera module. Alternatively, the electronic device further includes a sound cavity module, and the end of the flexible circuit board away from the mainboard is connected to the sound cavity module. In this embodiment, the data transmission capacity between the mainboard and the camera module and / or the data transmission capacity between the mainboard and the sound cavity module can be improved.

[0024] In one possible embodiment, the printed circuit board is a mainboard, and the electronic device further includes a first housing, a second housing, and a sub-board. The mainboard and sub-board are disposed within the first housing and the second housing, respectively, and the first and second housings are connected by a hinge. One end of the flexible printed circuit board is connected to the mainboard, and the other end of the flexible printed circuit board is connected to the sub-board via the first housing, the hinge, and the second housing. This embodiment improves data transmission capabilities between the mainboard and the sub-board, and reduces the bending radius of the flexible printed circuit board, thereby achieving a thinner and lighter electronic device.

[0025] In one possible implementation, the printed circuit board is a control board for a battery protection board, and the electronic device further includes a mainboard. The flexible printed circuit board is connected to the mainboard at one end distal from the control board. This embodiment helps reduce the area of ​​the battery protection board, improves the fast-charging power of the battery protection board, and provides a higher charging wattage for the battery protection board.

[0026] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the structure of an electronic device provided in one embodiment of the present application;

[0028] Figure 2 A schematic structural diagram of an electronic device in a folded state provided by another embodiment of the present application;

[0029] Figure 3 for Figure 2 A schematic diagram of the structure of the electronic device in the unfolded state;

[0030] Figure 4 A schematic structural diagram of an electronic device in a folded state provided by another embodiment of the present application;

[0031] Figure 5 for Figure 4 A schematic diagram of the structure of the electronic device in the unfolded state;

[0032] Figure 6 for Figure 2 Schematic diagram of the internal structure of the electronic equipment in;

[0033] Figure 7 A schematic diagram of the structure of the welding connection between the flexible circuit board and the printed circuit board in the related art;

[0034] Figure 8 A schematic diagram of the structure of a flexible circuit board and a printed circuit board being welded together in another related technology;

[0035] Figure 9 for Figure 4 A schematic cross-sectional structural diagram of the first shell in FIG.

[0036] Figure 10 for Figure 9 A schematic diagram of the connection structure between the main board and the flexible circuit board in the first embodiment;

[0037] Figure 11 for Figure 9 A schematic diagram of the connection structure between the main board and the flexible circuit board in the second embodiment;

[0038] Figure 12 for Figure 9 A schematic diagram of the connection structure between the main board and the flexible circuit board in the third embodiment;

[0039] Figure 13 for Figure 9 A schematic diagram of the connection structure between the main board and the flexible circuit board in the fourth embodiment;

[0040] Figure 14A schematic structural diagram of a circuit board assembly provided in one embodiment of the present application;

[0041] Figure 15 for Figure 14 Schematic diagram of the middle part structure;

[0042] Figure 16 To set Figure 14 Schematic diagram of the method when the metal lead is in the middle;

[0043] Figure 17 for Figure 14 A schematic diagram of the structure of part of the structure in another perspective;

[0044] FIG18( a ) to FIG18 ( d ) are flowcharts of a process for manufacturing a circuit board assembly according to an embodiment of the present application;

[0045] Figure 19 A schematic structural diagram of a circuit board assembly provided in another embodiment of the present application;

[0046] Figure 20 for Figure 19 A schematic diagram of the structure of part of the structure in another perspective;

[0047] Figure 21 A schematic structural diagram of a circuit board assembly provided in another embodiment of the present application;

[0048] Figure 22 for Figure 21 A schematic diagram of the structure of part of the structure in another perspective;

[0049] Figure 23 A schematic structural diagram of a circuit board assembly provided in another embodiment of the present application;

[0050] Figure 24 for Figure 23 A schematic diagram of the structure of part of the structure in another perspective;

[0051] Figure 25 A schematic structural diagram of a circuit board assembly provided in another embodiment of the present application;

[0052] Figure 26 for Figure 25 A schematic diagram of the structure of part of the structure in another perspective;

[0053] Figure 27 A schematic structural diagram of a flexible circuit board provided in one embodiment of the present application;

[0054] Figure 28 This is a layout diagram of the second pad provided in one embodiment of the present application;

[0055] Figure 29A layout diagram of the second pad provided in another embodiment of the present application;

[0056] Figure 30 A schematic structural diagram of a fourth pad provided in an embodiment of the present application;

[0057] Figure 31 A schematic cross-sectional view of a flexible circuit board provided in one embodiment of the present application;

[0058] Figure 32 for Figure 31 A schematic cross-sectional view of a portion of the flexible circuit board structure in FIG. 1 from another perspective;

[0059] Figure 33 for Figure 31 A schematic cross-sectional view of a portion of the flexible circuit board structure in FIG. 1 from another perspective;

[0060] Figure 34 This is a schematic cross-sectional structure diagram of a flexible circuit board provided in another embodiment of the present application.

[0061] 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. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0063] In the description of this application, unless otherwise specified or limited, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0064] In the description of this specification, it should be understood that the directional words such as "upper" and "lower" described in the embodiments of the present application are described from the perspectives shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should be understood that when it is mentioned that an element is connected to another element "on" or "under", it can not only be directly connected to the other element "on" or "under", but also indirectly connected to the other element "on" or "under" through an intermediate element.

[0065] Electronic devices (such as smartwatches, mobile phones, laptops, and other mobile terminals) are typically equipped with printed circuit boards (PCBs) and flexible printed circuit boards (FPCs). In some cases, the PCBs and FPCs need to be connected to each other to achieve electrical connectivity. For example, a PCB serves as the motherboard of a mobile phone, which includes but is not limited to a processor, antenna module, Bluetooth module, WiFi module, GPS module, power supply and charging module, or screen display and operation module. The FPC can be used to electrically connect the phone's screen assembly to the screen display and operation module on the motherboard, enabling the screen assembly to perform display or operation functions. Alternatively, the FPC can also be used to electrically connect the phone's motherboard to the battery protection board. Alternatively, in the case of a foldable phone, the FPC can span the hinge to form an electrical connection between the phone's motherboard and its sub-board. In related art, the PCBs and FPCs are connected via a board-to-board (BTB) connector. However, BTB connectors are bulky and require a large installation space, which is detrimental to the internal device layout of the electronic device, thus hindering the miniaturization of the electronic device.

[0066] The embodiments of the present application provide an electronic device that can solve the above-mentioned technical problems. The electronic device can be a smartwatch, a mobile phone, a tablet computer, an ultra-mobile personal computer (UMPC), a netbook, a cellular phone, a personal digital assistant (PDA), an augmented reality (AR) device, a virtual reality (VR) device, an artificial intelligence (AI) device, a wearable device, an in-vehicle device, a smart home device, and / or a smart city device. The embodiments of the present application do not impose any particular restrictions on the specific form of the above-mentioned electronic devices. For the sake of convenience, the following description uses a mobile phone as an example.

[0067] Figure 1 This is a schematic diagram of the structure of an electronic device 100 provided in one embodiment of the present application, when it is a candy bar device. The electronic device 100 includes a display assembly 101 and a housing 102. The display assembly 101 can be understood as the screen of the electronic device, having a display area for displaying image information, with the display area of ​​the display assembly 101 facing away from the housing 102.

[0068] Figure 2 This is a schematic diagram of the structure of an electronic device 100 in a folded state, provided as a dual-folding device, according to another embodiment of the present application. The electronic device 100 includes a display assembly 101 and a housing 102. The housing 102 includes a first housing 1021, a second housing 1022, and a first hinge 1023. The first housing 1021 and the second housing 1022 are rotatably connected via the first hinge 1023. When the first housing 1021 and the second housing 1022 rotate toward each other along the hinge 1023 to the folded state, the display assembly 101 is also folded and hidden between the first housing 1021 and the second housing 1022. In other words, at this point, the display assembly 101 is in a position that cannot be viewed by the user.

[0069] Figure 3 This is a structural diagram of the double-folding machine in the unfolded state. When the first shell 1021 and the second shell 1022 rotate away from each other along the first rotation axis 1023 to the unfolded state, the first shell 1021 and the second shell 1022 are in the same plane. At this time, the display component 101 is also in the unfolded state. The display component 101 can provide a larger display area, bringing a good visual experience and operating experience to the user.

[0070] Figure 4 This is a schematic diagram of the structure of an electronic device 100 in a folded state when it is a three-fold device according to another embodiment of the present application. The housing 102 includes a first housing 1021, a second housing 1022, a third housing 1024, a first rotating shaft 1023, and a second rotating shaft 1025. The second housing 1022 is rotatably connected to the first housing 1021 via the first rotating shaft 1023, and the second housing 1022 is rotatably connected to the third housing 1024 via the second rotating shaft 1025. When the electronic device 100 is in the folded state, a portion of the display assembly 101 is located outside the electronic device 100, and the content displayed in this portion can be seen by the user. Another portion of the display assembly 101 is hidden between the second housing 1022 and the third housing 1024, and the content displayed in this portion cannot be seen by the user.

[0071] Figure 5This is a schematic diagram of the structure of the trifold device in the unfolded state. The first housing 1021, second housing 1022, and third housing 1024 can rotate along the first and second rotation axes 1023 and 1025, respectively, to the same plane. When the electronic device 100 is in the unfolded state, the display assembly 101 is also in the unfolded state, providing a larger display area and providing a good visual and operational experience for the user.

[0072] It should be noted that the embodiment of the present application does not limit the relative rotation direction between the first shell 1021, the second shell 1022 and the third shell 1023. Figure 2-Figure 5 The structural diagram of the electronic device 100 is only an example diagram of one embodiment.

[0073] The following describes the internal structure of the electronic device 100 by taking the electronic device 100 as a double-folding device as an example.

[0074] like Figure 6As shown, electronic device 100 includes a mainboard 103 and a sub-board 104. One of mainboard 103 and sub-board 104 is disposed within a first housing 1021, and the other is disposed within a second housing 1022. In this embodiment, the mainboard 103 is disposed within the first housing 1021 and the sub-board 104 is disposed within the second housing 1022. Mainboard 103 integrates chips or interfaces including, but not limited to, a system-on-a-chip (SOC) 1031, a universal flash storage (UFS) chip 1032, and a charging structure 1033. Mainboard 103 and sub-board 104 are electrically connected via a first flexible printed circuit board 1051. The first flexible printed circuit board 1051 can span a first hinge 1023, either by passing through the first hinge 1023 or by bypassing the outer surface of the first hinge 1023. The electronic device also includes a first battery 1061 and a second battery 1062. One of the first battery 1061 and the second battery 1062 is disposed within the first housing 1021, and the other is disposed within the second housing 1022. The embodiment of the present application takes the example of the first battery 1061 being disposed within the first housing 1021 and the second battery 1062 being disposed within the second housing 1022. The second battery 1062 is electrically connected to the auxiliary board 104 via the second flexible printed circuit board 1052. A battery protection board 107 electrically connected to the first battery 1061 is also disposed within the first housing 1021. The battery protection board 107 typically includes functions such as overcharge protection, over-discharge protection, overcurrent protection, and short-circuit protection to prevent damage to the first battery 1061 during use. The battery protection board 107 includes a control board, which is electrically connected to the main board 103 via a third flexible printed circuit board 1053. The first housing 1021 also houses a camera module 108 and a sound cavity module 109. The camera module 108 is the core component of the phone's camera system, responsible for capturing images and converting them into digital signals for the phone's camera function. It is electrically connected to the mainboard via a fourth flexible printed circuit board 1054. The sound cavity module 109 is a key component responsible for producing sound and is crucial for providing a high-quality audio experience. It is electrically connected to the mainboard via a fifth flexible printed circuit board 1055.

[0075] It should be noted that in the embodiments of the present application, all the structural layout diagrams are only used to illustrate the composition, general layout orientation and connection mode of the partial structure of the electronic device, and do not limit the specific structure type, position, shape, etc. In other embodiments of the present application, the electronic device 100 may include Figure 8 The components shown in the figure may be implemented in hardware, software or a combination of software and hardware.

[0076] The main board 103, the sub-board 104 and the control board on the battery protection board 107 are all printed circuit boards. In the related art, the printed circuit board and the flexible circuit board can be connected through a board-to-board connector. However, the board-to-board connector itself is large in size and requires a large installation space, which is not conducive to the layout of components inside the electronic device, thereby affecting the realization of miniaturization of the electronic device. Or, as Figure 7 As shown, the printed circuit board 010 and the flexible circuit board 020 can be stacked along the thickness direction Z of the printed circuit board 010 and electrically connected by welding. A printed circuit board pad 011 is provided on the printed circuit board 010, and a flexible circuit board pad 021 corresponding to the position of the printed circuit board pad 011 is provided on the flexible circuit board 020. The printed circuit board pad 011 and the flexible circuit board pad 021 are fixed and electrically connected by solder paste 012. However, since the solder paste 012 has a certain thickness, the overall thickness of the printed circuit board 010 and the flexible circuit board 020 after connection will be too large, and it will also take up a large installation space, which is not conducive to the layout of the components inside the electronic device, thereby affecting the realization of miniaturization of the electronic device. Moreover, when the thickness of the connection between the flexible circuit board pad 020 and the printed circuit board 010 is too large, the bending radius of the flexible circuit board 020 will increase, and a larger bending space will be required. Therefore, the use of solder paste 012 is not suitable for the connection between the printed circuit board 010 and the flexible circuit board 020. Figure 7 The welding method shown will be very detrimental to the thinning of the folding machine.

[0077] In order to reduce the overall thickness of the printed circuit board 010 and the flexible circuit board 020 after being connected, some related technologies use FOB welding technology (FPC on Board) to achieve the electrical connection between the printed circuit board 010 and the flexible circuit board 020. Specifically, Figure 8As shown, printed circuit board (PCB) 010 is provided with PCB pads 011, and flexible PCB 020 is provided with flexible PCB pads 021 corresponding to the positions of PCB pads 011. Flexible PCB pads 021 include tin-through holes with a through-hole structure and a connecting metal layer. The connecting metal layer is provided on the inner wall of the tin-through hole and the periphery of the upper and lower openings of the tin-through hole. Heated solder paste 012 can enter the tin-through hole under the pressure of flexible PCB 020 and emerge from the side of flexible PCB 020 facing away from PCB 010. After curing, solder paste 012 can connect and secure PCB 010 to flexible PCB 020, and solder paste 012 can also form an electrical connection with the metal connecting layer, thereby achieving electrical connection between PCB 010 and flexible PCB 020. However, since the FOB welding technology requires setting through holes on the flexible circuit board 020, it will affect the routing of the flexible circuit board 020, resulting in a decrease in the wiring density and the number of pads of the flexible circuit board 020, which in turn leads to poor current flow capacity of the flexible circuit board 020, which is not conducive to data transmission between the flexible circuit board 020 and the electrical components on the printed circuit board 010, and cannot meet the current demand of electronic equipment to improve the current flow capacity of flexible circuit boards.

[0078] The electronic device 100 provided in the embodiment of the present application can improve the flow capacity of the flexible circuit board while reducing the overall thickness after the printed circuit board and the flexible circuit board are fixedly connected.

[0079] like Figure 9As shown, the first shell 1021 includes a middle frame 1021a, a rear shell 1021b and a decorative cover 1021c. Along the thickness direction Z of the electronic device 100, the display module 101 is fixedly connected to the side of the middle frame 1021a away from the rear shell 1021b. A graphite layer 1011 and a first heat spreader 1012 are also arranged between the display module 101 and the middle frame 1021a to enhance the heat dissipation capacity of the electronic device 100. The motherboard 103 is located in the space enclosed by the middle frame 1021a, the rear housing 1021b, and the decorative cover 1021c. The motherboard 103 is fixedly connected to the middle frame 1021a via a fixing member 1021d. Along the thickness direction Z of the electronic device 100, a power management unit (PMU) 1034, a radio frequency power management integrated device (RFPMID) 1035, and a flexible circuit board 105 are mounted on the side of the motherboard 103 facing the rear housing 1021b. A system-on-chip (SoC) 1031 and a universal flash memory chip 1032 are mounted on the side of the motherboard 103 facing the display assembly 101. Other electrical components 1039 may also be mounted on the side of the motherboard 103. A low-power double data rate dynamic random access memory (LPDDR) 1036 is also mounted on the side of the SoC 1031 away from the motherboard 103. Specifically, the power management unit 1034, the RF power management integrated device 1035, the system-on-chip 1031, the universal flash memory chip 1032, and other electrical components 1039 can be soldered and fixed to the mainboard 103 to form an electrical connection. The system-on-chip 1031 and the low-power double data rate dynamic random access memory 1036 can also be soldered and fixed to form an electrical connection.

[0080] A first shielding cover 1021e and a second shielding cover 1021f are also provided in the first shell 1021. The first shielding cover 1021e is fixed to the side surface of the mainboard 103 facing the rear shell 1021b. The first shielding cover 1021e and the mainboard 103 together form a first shielding cavity 1037. The power management unit 1034 and the RF power management integrated device 1035 are located in the first shielding cavity 1037. The first shielding cover 1021e can shield the signals of the power management unit 1034 and the RF power management integrated device 1035. A second shielding cover 1021f is fixed to the side of the mainboard 103 facing the display assembly 101. Together, the second shielding cover 1021f and the mainboard 103 form a second shielding cavity 1038. The system-on-chip (SoC) 1031, the universal flash memory chip 1032, the low-power double data rate dynamic random access memory (DRAM) 1036, and other electrical components 1039 are located within this second shielding cavity 1038. The second shielding cover 1021f provides signal shielding for the SoC 1031, the universal flash memory chip 1032, the low-power double data rate dynamic random access memory (DRAM) 1036, and other electrical components 1039. Furthermore, a thermal interface material (TIM) 1021g and a second vapor chamber 1021h are disposed between the second shielding cover 1021f and the midframe 1021a to enhance the heat dissipation capability of the electronic device 100. The flexible circuit board 105 is any one of the first flexible circuit board 1051 , the third flexible circuit board 1053 , the fourth flexible circuit board 1054 , and the fifth flexible circuit board 1055 .

[0081] like Figure 10 As shown, when the flexible circuit board 105 is a first flexible circuit board 1051, along the length direction X of the first flexible circuit board 1051, both ends of the first flexible circuit board 1051 are electrically connected to the main board 103 and the sub-board 104 respectively. Specifically, the first flexible circuit board 1051 and the main board 103 can be connected along the thickness direction Z of the first flexible circuit board 1051, and the first flexible circuit board 1051 and the sub-board 104 can be connected along the thickness direction Z of the first flexible circuit board 1051.

[0082] like Figure 11As shown, when the flexible circuit board 105 is a third flexible circuit board 1053, along the length direction Y of the third flexible circuit board 1053, its two ends are electrically connected to the mainboard 103 and the battery protection board 107, respectively. The third flexible circuit board 1053 and the mainboard 103 can be welded together along the thickness direction Z of the third flexible circuit board 1053. The electronic device 100 also includes a first reinforcement portion 1053a. The first reinforcement portion 1053a is fixed to the side of the third flexible circuit board 1053 facing away from the battery protection board 107 along the thickness direction Z of the third flexible circuit board 1053 to enhance the structural strength and impact resistance of the third flexible circuit board 1053. The first reinforcement portion 1053a can be a metal reinforcement welded to the third flexible circuit board 1053. Metal materials have good thermal conductivity, which can improve the thermal conductivity of the third flexible circuit board 1053 and help dissipate heat from the third flexible circuit board 1053.

[0083] like Figure 12 As shown, when the flexible circuit board 105 is a fourth flexible circuit board 1054, along the length direction Y of the fourth flexible circuit board 1054, two ends of the fourth flexible circuit board 1054 are electrically connected to the mainboard 103 and the camera module 108, respectively. The fourth flexible circuit board 1054 and the mainboard 103 can be connected along the thickness direction Z of the fourth flexible circuit board 1054, with the camera module 108 and the mainboard 103 located on the same side of the fourth flexible circuit board 1054. The electronic device 100 also includes a second reinforcement portion 1054a, which is fixed to the side of the fourth flexible circuit board 1054 away from the camera module 108 along the thickness direction Z of the fourth flexible circuit board 1054 to enhance the structural strength and impact resistance of the fourth flexible circuit board 1054. The second reinforcement portion 1054a can be a metal reinforcement welded to the fourth flexible circuit board 1054. Metal materials have good thermal conductivity, which can improve the thermal conductivity of the fourth flexible circuit board 1054 and help dissipate heat from the fourth flexible circuit board 1054.

[0084] like Figure 13As shown, when the flexible circuit board 105 is the fifth flexible circuit board 1055, along its length direction Y, its two ends are electrically connected to the mainboard 103 and the sound cavity module 109, respectively. The fifth flexible circuit board 1055 and the mainboard 103 can be connected along its thickness direction Z, with the sound cavity module 109 and the mainboard 103 located on different sides of the fifth flexible circuit board 1055. The electronic device 100 also includes a third reinforcement portion 1055a, affixed to the side of the fifth flexible circuit board 1055 facing away from the sound cavity module 109 along its thickness direction Z, to enhance the structural strength and impact resistance of the fifth flexible circuit board 1055. The third reinforcement portion 1055a can be a metal reinforcement welded to the fifth flexible circuit board 1055. Metal materials have good thermal conductivity, which can improve the thermal conductivity of the fifth flexible circuit board 1055 and facilitate heat dissipation.

[0085] The present embodiment also provides a circuit board assembly 10 that can be installed within an electronic device 100. The circuit board assembly 10 includes a printed circuit board 1 and a flexible circuit board 2. The printed circuit board 1 can specifically be the aforementioned main board 103, and accordingly, the flexible circuit board 2 can specifically be the aforementioned flexible circuit board 105, that is, the flexible circuit board 2 can be any one of the first flexible circuit board 1051, the third flexible circuit board 1053, the fourth flexible circuit board 1054, and the fifth flexible circuit board 1055. Alternatively, the printed circuit board 1 can specifically be the aforementioned sub-board 104, and accordingly, the flexible circuit board 2 can specifically be the second flexible circuit board 1052. Alternatively, the printed circuit board 1 can specifically be the control board on the battery protection board 107, and accordingly, the flexible circuit board 2 can specifically be the third flexible circuit board 1053.

[0086] The specific structure of the circuit board assembly 10 is described below by taking the printed circuit board 1 as the main board 103 and the flexible circuit board 2 as the first flexible circuit board 1051 as an example.

[0087] Figure 14 This is a schematic diagram of the structure of the circuit board assembly 10 provided in one embodiment of the present application. Figure 14As shown, the printed circuit board 1 includes a main body 11 and a connecting plate 12. Along the thickness direction Z of the connecting plate 12, one side surface of the connecting plate 12 is used to form an electrical connection with the main body 11, and the other side surface is used to form an electrical connection with the flexible circuit board 2, so as to achieve electrical conduction between the printed circuit board 1 and the flexible circuit board 2. In particular, along the thickness direction Z of the connecting plate 12, a sixth solder pad 121 is provided on the side surface of the connecting plate 12 facing the main body 11, and a seventh solder pad 111 corresponding to the sixth solder pad 121 is provided on the side surface of the main body 11 facing the connecting plate 12. The main body 11 and the connecting plate 12 can be fixed and electrically connected by welding the sixth solder pad 121 and the seventh solder pad 111. The specific shapes of the sixth solder pad 121 and the seventh solder pad 111 can be rectangular, square, circular, or diamond-shaped, etc., and are not limited in this embodiment of the present application. In addition, the interior of the connecting plate 12 can have a double-layer or triple-layer wiring structure. The connecting plate 12 can be provided with through holes, blind vias, or buried vias to achieve electrical connection between different layers within the connecting plate 12, and this is not limited in the present embodiment. The connecting plate 12 is provided with a first solder pad 13 and a third solder pad 14, and the flexible circuit board 2 is provided with a second solder pad 21 and a fourth solder pad 22. The third solder pad 14 and the fourth solder pad 22 are welded and fixed to form an electrical connection. The first solder pad 13 and the second solder pad 21 are bonded to form an electrical connection via a metal lead 3.

[0088] First, the specific connection structure of the third pad 14 and the fourth pad 22 is introduced: the third pad 14 and the fourth pad 22 can be connected by FOB welding technology, refer to Figure 15 As shown, the fourth solder pad 22 includes a through hole 221 that penetrates the flexible circuit board 2 along the thickness direction Z of the flexible circuit board 2. A metal connection layer 222 is provided on the inner wall of the through hole 221 and the outer periphery of the upper and lower openings of the through hole 221. Along the thickness direction Z of the flexible circuit board 2, a third solder pad 13 is provided on the surface of the connecting plate 12 facing the flexible circuit board 2. The third solder pad 13 is used for printing solder paste, which may include metallic tin and flux. The solder paste melts upon heating. Aligning the through hole 221 of the fourth solder pad 22 with the melted solder paste and then applying downward pressure to the flexible circuit board 2 can squeeze the melted solder paste into the through hole 221. When the solder paste cools and solidifies, a solder joint 15 is formed. The solder joint 15 is fixedly connected to the metal connection layer 222 in the through hole 221 and forms a conductive connection, thereby soldering the third solder pad 14 to the fourth solder pad 22 and forming an electrical connection. Among them, in order to improve the welding reliability and electrical connection reliability of the third solder pad 14 and the fourth solder pad 22, the solder paste is preferably able to completely penetrate the through hole 221 and overflow from the opening on the side of the through hole 221 away from the third solder pad 14 and then be fixedly connected to the metal connection layer 222 outside the opening, that is, the structure of the solder joint 15 is preferably able to fill the through hole 221, and the two ends of the solder joint 15 along the thickness direction Z of the flexible circuit board 2 can respectively cover the openings on both sides of the through hole 221.

[0089] Next, the specific connection structure of the first pad 13 and the second pad 21 is described: along the thickness direction Z of the flexible circuit board 2, the first pad 13 is arranged on the side of the connecting plate 12 facing the flexible circuit board 2, and the second pad 21 is arranged on the side of the flexible circuit board 2 away from the connecting plate 12. The first pad 13 and the second pad 21 are electrically connected using wire bonding technology. The two ends of the metal lead 3 are respectively welded to the first pad 13 and the second pad 21, so that the first pad 13 and the second pad 21 can be bonded together via the metal lead 3. The material of the metal lead 3 can specifically be gold wire, aluminum wire, or copper wire, which is not limited in this embodiment of the present application. The material of the second pad 21 must match the material of the metal lead 3 to ensure that a certain intermetallic compound can be formed between the metal lead 3 and the second pad 21, thereby ensuring the welding strength between the metal lead 3 and the second pad 21. For example, when the metal lead 3 is a gold wire, the second pad 21 can be a gold pad, an aluminum pad, a silver pad, or a copper pad. When the metal lead 3 is an aluminum wire, the second pad 21 can be an aluminum pad, a silver pad, or a nickel pad. When the metal lead 3 is a copper wire, the second pad 21 can be a copper pad. The metal lead 3 and the second pad 21 can also be made of other materials, which is not limited in this embodiment of the present application.

[0090] refer to Figure 16 As shown, taking the case where the metal lead 3 is made of gold wire and the bonding connection between the first pad 13 and the second pad 21 adopts the "thermosonic gold ball wire bonding method" as an example, the bonding connection process of the metal lead 3 and the first pad 13 and the second pad 21 is introduced: first, the gold wire 300 is passed through the small hole in the center of the capillary cleaver 310, and the temperature of the end of the gold wire 300 is increased. After the gold wire 300 is melted, a gold ball 301 is formed. The clamp 320 holding the gold wire 300 is opened, and heat, pressure, and ultrasonic vibration are applied to the capillary cleaver 310. When the capillary cleaver 310 contacts the fourth pad 22, the gold ball 301 will adhere to the fourth pad 22, completing a ball bonding. The capillary cleaver 310 is then lifted, and after forming a gold ball 301 again, heat, pressure, and ultrasonic vibration are applied to the capillary cleaver 310 to press the second gold ball 301 onto the first pad 13. Finally, the gold wire 300 is disconnected by the clamp 320, thereby completing the second bonding, thereby connecting and fixing the two ends of the metal lead 3 to the first pad 13 and the second pad 21, respectively. Of course, the gold ball 301 can also be replaced by a wedge bonding structure, which is not limited in this embodiment of the present application.

[0091] Because the second pads 21 are connected to the first pads 13 by bonding, no through-holes are required in the second pads 21, allowing the flexible circuit board 2 to achieve a double-sided fabric effect. Along the thickness direction Z of the flexible circuit board 2, the chip 4 can be positioned on the side of the flexible circuit board 2 away from the second pads 21. The chip 4 and the flexible circuit board 2 can be secured and electrically connected via solder 23. Along the thickness direction Z of the flexible circuit board 4, the inner side of the connecting plate 12 should be secured to the outer side of the flexible circuit board 2 via the third and fourth pads 14 and 22, providing mounting space for the chip 4. Furthermore, this positional relationship between the connecting plate 12 and the flexible circuit board 2 facilitates the bonding connection between the first pads 13 and the second pads 21. In addition, a filling adhesive layer 41 can be provided between the chip 4 and the flexible circuit board 2. The filling adhesive layer 41 can specifically be an ultraviolet-curing film adhesive (UF). The ultraviolet-curing film adhesive has high bonding strength, can withstand a certain amount of mechanical stress, and has a certain degree of flexibility, can absorb a certain amount of impact and vibration, so as to improve the connection strength between the chip 4 and the flexible circuit board 2, thereby improving the structural stability of the circuit board assembly 10.

[0092] The circuit board assembly 10 also includes a reinforcing member 7, which is fixed to the side surface of the flexible circuit board 2 along the thickness direction Z of the flexible circuit board 2, where the chip 4 is located. Specifically, the reinforcing member 7 can be arranged circumferentially around the chip 4 to enhance the bending strength and impact resistance of the portion of the structure connecting the flexible circuit board 2 and the chip 4, reducing the risk of damage to the structure connecting the flexible circuit board 2 and the chip 4 due to bending, thereby improving the stability and reliability of the chip 4's installation on the flexible circuit board 2. Furthermore, the reinforcing member 7 also provides protection for the chip 4 along the circumference of the chip 4, enhancing its impact resistance. The reinforcing member 7 can be welded to the fifth solder pad 24 on the flexible circuit board 2. The structure of the fifth solder pad 24 can be the same as the second solder pad 21, or it can have other structures, which is not limited in this embodiment of the present application. Of course, the reinforcing member 7 can also be fixedly connected to the flexible circuit board 2 through other connection methods, which is not limited in this embodiment of the present application. The reinforcing piece 7 can specifically be a metal reinforcement. The metal reinforcement can not only improve the mechanical strength of the flexible circuit board 2 , but also help the flexible circuit board 2 dissipate heat, thereby improving the thermal conductivity of the flexible circuit board 2 .

[0093] The circuit board assembly 10 further includes a reinforcement frame 6, which is fixed to the side surface of the flexible circuit board 2 provided with the second solder pad 21 along the thickness direction Z of the flexible circuit board 2. The reinforcement frame 6 can be fixedly connected to the flexible circuit board 2 by welding or gluing, which is not limited in this embodiment of the present application. Figure 17As shown, the reinforcement frame 6 has a first accommodating space 61, and the second and fourth solder pads 21, 22 are both located within the first accommodating space 61. That is, the reinforcement frame 6 is disposed around the second and fourth solder pads 21, 22. This allows the reinforcement frame 6 to enhance the mechanical strength of the flexible circuit board 2 while also supporting the flexible circuit board 2 from the periphery of the second and fourth solder pads 21, 22 to maintain the flatness of the flexible circuit board 2, thereby enhancing the structural stability of the flexible circuit board 2. To ensure that the reinforcement frame 6 effectively reinforces the flexible circuit board 2 while not occupying excessive space on the surface of the flexible circuit board 2, the width of the reinforcement frame 6 can be 0.1 mm to 1 mm, specifically 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm. Other values ​​within the aforementioned range are also possible, but this is not a limitation of the present embodiment. In addition, the material of the reinforcement frame 6 can specifically be a metal material, a plastic material, or a mixed material of metal and plastic, which is not limited in the embodiment of the present application.

[0094] The circuit board assembly 10 also includes an encapsulation structure 5, which includes a first sub-encapsulation structure 51 and a second sub-encapsulation structure 52. The first sub-encapsulation structure 51 is fixed to a side surface of the connecting plate 12 having the first and third pads 13, 14. The first, second, third, and fourth pads 21, 24, 22 are all located within the first sub-encapsulation structure 51. The first sub-encapsulation structure 51 is used to encapsulate the connection between the printed circuit board 1 and the flexible circuit board 2, protecting the connection from the external environment and reducing the risk of physical damage or environmental corrosion. A second accommodating space 18 is formed between the chip 4, the connecting plate 12, and the main body 11. The second sub-encapsulation structure 52 fills the second accommodating space 18 and is used to encapsulate the chip 4, improving the stability and reliability of the connection between the chip 4 and the flexible circuit board 2. Therefore, by providing the packaging structure 5, the circuit board assembly 10 can be protected, the mechanical strength of the circuit board assembly 10 can be improved, and the reliability and stability of the circuit board assembly 10 in various environments can be ensured, thereby facilitating the improvement of the service life of the electronic device 100. Specifically, the packaging structure 5 can be manufactured through a molding process, that is, molten material (such as plastic, resin, metal, etc.) is injected into a pre-designed mold. After the material cools and solidifies, the packaging structure 5 of the desired shape can be formed. Of course, the packaging structure 5 can also be manufactured through other processes, and the embodiments of the present application are not limited thereto.

[0095] In summary, in the circuit board assembly 10 provided in the above embodiment, the printed circuit board 1 and the flexible circuit board 2 are connected by a combination of FOB welding technology and wire bonding technology, which is beneficial to reducing the overall thickness of the circuit board assembly 10 and reducing the bending radius of the flexible circuit board 2, thereby reducing the space occupied by the circuit board assembly 10, and is beneficial to achieving miniaturization and lightweight electronic equipment 100. At the same time, since the second solder pad 21 does not need to be provided with a through-hole structure, the number of openings on the flexible circuit board 2 can be reduced, which not only improves the structural strength of the flexible circuit board 2, but also improves the wiring density of the flexible circuit board 2 and the number of solder pads on the flexible circuit board 2, thereby improving the flow capacity of the flexible circuit board 2, forming a multi-channel flow between the printed circuit board 1 and the flexible circuit board 2, increasing the path current and achieving a cooling effect, so as to improve the service life of the components in the circuit board assembly 10, and thus is beneficial to improving the service life of the electronic device.

[0096] It should be noted that the embodiments of this application provide Figures 10-17 The first pad 13 , the second pad 21 , the third pad 14 , the fourth pad 22 , the fifth pad 24 , the sixth pad 121 and the seventh pad 111 are merely schematic structures and are not intended to limit their specific structures and shapes.

[0097] The present application also provides a method for processing a circuit board assembly 10, which is used to process and produce the circuit board assembly 10 described in the above embodiment. Figures 18(a) to 18(d) are schematic flow charts of the processing method. Referring to Figures 18(a) to 18(d), the processing method specifically includes:

[0098] Step S1 : providing a flexible circuit board 2 provided with a second solder pad 21 and a fourth solder pad 22 .

[0099] Step S2 : fixing the reinforcing frame 6 to the surface of the flexible circuit board 2 on one side where the second solder pad 21 is provided, along the thickness direction Z of the flexible circuit board 2 .

[0100] In this step, the reinforcement frame 6 is first installed on the flexible circuit board 2 to ensure the flatness of the flexible circuit board 2 and facilitate subsequent processing.

[0101] Step S3 : soldering the chip 4 and the reinforcing member 7 to a surface of the flexible circuit board 2 away from the second soldering pad 21 along the thickness direction Z of the flexible circuit board 2 .

[0102] As shown in Figure 18(a), in this step, the flexible circuit board 2 (FPC) 2 can be placed with its surface provided with the second solder pad 21 facing downward on the first support fixture 200. A cover fixture 210 is then placed on the upward-facing surface of the FPC 2 to press the FPC 2 against the support fixture 200 and prevent it from shifting. The chip 4 and reinforcement 7 are then soldered to the upward-facing surface of the FPC 2 using solder 23 and the fifth solder pad 24, respectively, to complete the connection between the chip 4 and the FPC 2 and enhance its mechanical strength.

[0103] Step S4 : performing a dispensing and curing process between the chip 4 and the flexible circuit board 2 along the thickness direction Z of the flexible circuit board 2 to form a filling glue layer 41 .

[0104] As shown in FIG18(b), in this step, a UV-curable film adhesive can be applied between the chip 4 and the flexible circuit board 2 by dispensing. The dispensing area is then illuminated with a UV light source. Once the UV-curable film adhesive is cured, a filler adhesive layer 41 is formed. The provision of filler adhesive layer 41 not only improves the connection between the chip 4 and the flexible circuit board 2 but also absorbs external shock and vibration to a certain extent, thereby protecting the chip 4. Furthermore, the UV-curable film adhesive has the characteristic of rapid curing, which helps improve the processing efficiency of the circuit board assembly 10.

[0105] Step S5: providing a connecting plate 12 provided with a first solder pad 13 and a second solder pad 14 , and welding the third solder pad 14 on the connecting plate 12 to the fourth solder pad 22 on the flexible circuit board 2 through the solder joint 15 , so that at least part of the solder joint 15 is located in the through hole 221 .

[0106] In this step, the FOB welding technology is used to weld the connecting plate 12 and the flexible circuit board 2 into a whole, so as to achieve a fixed connection and electrical connection between the connecting plate 12 and the flexible circuit board 2, while ensuring that the thickness of the whole formed by the connecting plate 12 and the flexible circuit board 2 is minimized.

[0107] Step S6 : bonding the first pad 13 on the connection board 12 to the second pad 21 on the flexible circuit board 2 via the metal wire 3 .

[0108] As shown in FIG18 (c), the connection plate 12 and the flexible circuit board 2 are moved as a whole onto the second support fixture 220, so that the chip 4 is placed downward and supported by the second support fixture 220, and the side surface of the connection plate 12 provided with the first solder pad 13 and the side surface of the flexible circuit board 2 provided with the second solder pad 21 are placed facing each other, so as to facilitate the bonding connection between the first solder pad 13 and the second solder pad 21.

[0109] Step S7 : performing packaging processing on the side of the connecting plate 12 facing the flexible circuit board 2 along the thickness direction Z of the connecting plate 12 so that the first pad 13 , the second pad 21 , the third pad 14 , the fourth pad 22 and the chip 4 are located in the packaging structure 5 .

[0110] As shown in FIG18 (d), in this step, the flexible circuit board 2 and the connecting plate 12 connected as one can be moved onto the third supporting tool 230, and then the first packaging structure 51 and the second packaging structure 52 are simultaneously formed through a molding process to provide reliable protection for the connection portion between the flexible circuit board 2 and the connecting plate 12.

[0111] Step S8 : welding and fixing the main body 11 and the surface of the connecting plate 12 away from the flexible circuit board 2 along the thickness direction Z of the connecting plate 12 .

[0112] In this step, the flexible circuit board 2 and the connecting plate 12 that are connected and packaged into one are moved to the top of the main body 11, and the connecting plate 12 is welded to the surface of the main body 11 to complete the assembly of the circuit board assembly 10, and finally a circuit board assembly 10 with a small thickness, high reliability and large flow capacity is obtained.

[0113] Figure 19 This is a structural diagram of a circuit board assembly 10 provided in another embodiment of the present application, as shown in FIG. Figure 19 As shown, circuit board assembly 10 includes a printed circuit board 1, a flexible circuit board 2, and a chip 4. The printed circuit board 1 comprises only a main body 11, with a first solder pad 13 and a third solder pad 14 provided on its surface. The flexible circuit board 2 is provided with a second solder pad 21 and a fourth solder pad 22. The first solder pad 13 and the second solder pad 21 are bonded together via metal wires 3, while the third solder pad 14 and the fourth solder pad 22 are connected using FOB welding technology. A third receiving groove 17 is also provided on the side of the main body 11 where the first and third solder pads 13, 14 are provided. The chip 4 is soldered to the side of the flexible circuit board 2 facing the main body 11, with at least a portion of the chip 4 positioned within the third receiving groove 17. This makes the circuit board assembly 10 more compact and reduces its overall thickness. The specific connection structures of the first solder pad 13 and the second solder pad 21, the third solder pad 14 and the fourth solder pad 22, and the chip 4 and the flexible circuit board 2 are identical to those described in the previous embodiment and will not be further described here.

[0114] The circuit board assembly 10 also includes a reinforcement frame 6, which is fixed to the side surface of the flexible circuit board 2 where the second solder pad 21 is located, along the thickness direction Z of the flexible circuit board 2. The reinforcement frame 6 is used to maintain the flatness of the flexible circuit board 2, thereby improving the structural stability of the flexible circuit board 2. Furthermore, in this embodiment, because the flexible circuit board 2 is directly soldered to the main body 11 and the chip 4 is located within the third receiving groove 17, the flexible circuit board 2 is adequately supported, eliminating the need for additional reinforcement structures on the side surface of the flexible circuit board 2 where the chip 4 is located. This simplifies the structure of the circuit board assembly 10 and improves the processing efficiency of the circuit board assembly 10.

[0115] The circuit board assembly 10 also includes electronic components 8, combined with Figure 20 As shown, the electronic component 8 includes, but is not limited to, one of a capacitor, a resistor, and an inductor. The electronic component 8 is fixed to the flexible circuit board 2, specifically, it can be soldered to the second solder pad 21. That is, the electronic component 8 and the chip 4 are respectively arranged on two opposite surfaces of the flexible circuit board 2, thereby achieving double-sided wiring of the flexible circuit board 2 and improving the wiring density of the flexible circuit board 2. Moreover, the connection path between the electronic component 8 and the flexible circuit board 2 can be shortened, thereby improving the structural compactness of the circuit board assembly 10. The embodiment of the present application does not limit the specific number of electronic components 8, and can be one or more.

[0116] The circuit board assembly 10 also includes a packaging structure 5, which is fixed on a side surface of the main body 1 having a third receiving groove 17. The first solder pad 13, the second solder pad 21, the third solder pad 14, the fourth solder pad 22 and the electronic component 8 are all located in the packaging structure 5. At least part of the packaging structure 5 can also be filled in the third receiving groove 17 to protect the chip 4. Therefore, by setting the packaging structure 5, the circuit board assembly 10 can be protected, the mechanical strength of the circuit board assembly 10 can be improved, and the reliability and stability of the circuit board assembly 10 in various environments can be ensured, which is beneficial to improving the service life of the electronic device 100.

[0117] Figure 21 This is a structural diagram of a circuit board assembly 10 provided in another embodiment of the present application, as shown in FIG. Figure 21As shown, circuit board assembly 10 includes a printed circuit board 1, a flexible circuit board 2, and a chip 4. Printed circuit board 1 comprises only a main body 11, which is provided with a first receiving groove 16. The bottom wall of first receiving groove 16 is provided with a first solder pad 13 and a third solder pad 14. Flexible circuit board 2 is located within first receiving groove 16 and is provided with a second solder pad 21 and a fourth solder pad 22. First solder pad 13 and second solder pad 21 are bonded together via metal wires 3, while third solder pad 14 and fourth solder pad 22 are connected using FOB soldering technology. This means that flexible circuit board 2 can be accommodated within main body 11. A second receiving groove 161 is also provided on the bottom wall of first receiving groove 16. Chip 4 is soldered to a side surface of flexible circuit board 2 facing second receiving groove 161, with at least a portion of chip 4 located within second receiving groove 161. This further compacts the structure of circuit board assembly 10 and reduces its overall thickness. Among them, the specific connection structure between the first pad 13 and the second pad 21, the specific connection structure between the third pad 14 and the fourth pad 22, and the specific connection structure between the chip 4 and the flexible circuit board 2 are the same as those in the above embodiment and will not be repeated here.

[0118] The circuit board assembly 10 also includes a reinforcement frame 6, combined with Figure 22 As shown, along the thickness direction Z of the flexible circuit board 2, a reinforcement frame 6 is fixed to the side surface of the flexible circuit board 2 where the second solder pad 21 is provided. The reinforcement frame 6 is used to maintain the flatness of the flexible circuit board 2, thereby improving the structural stability of the flexible circuit board 2. Furthermore, in this embodiment, the flexible circuit board 2 is adequately supported, eliminating the need for additional reinforcement structures on the side surface of the flexible circuit board 2 where the chip 4 is provided. This helps simplify the structure of the circuit board assembly 10 and improves the processing efficiency of the circuit board assembly 10.

[0119] The circuit board assembly 10 also includes an encapsulation structure 5, which is filled within the first receiving groove 16. The first solder pad 13, the second solder pad 21, the third solder pad 14, and the fourth solder pad 22 are all located within the encapsulation structure 5. The encapsulation structure 5 is flush with the surface of the main body 11, so that the overall thickness of the circuit board assembly 10 is only the thickness of the main body 11, thereby minimizing the thickness of the circuit board assembly 10. In addition, at least a portion of the encapsulation structure 5 can also be filled within the second receiving groove 161 to protect the chip 4. The provision of the encapsulation structure 5 can protect the circuit board assembly 10, improve the mechanical strength of the circuit board assembly 10, and ensure the reliability and stability of the circuit board assembly 10 in various environments, thereby facilitating the improvement of the service life of the electronic device 100.

[0120] Figure 23 This is a structural diagram of a circuit board assembly 10 provided in another embodiment of the present application, as shown in FIG. Figure 23As shown, circuit board assembly 10 includes a printed circuit board 1 and a flexible circuit board 2. Printed circuit board 1 comprises only a main body 11, with a first receiving groove 16 disposed on its surface. Main body 11 is also provided with a first solder pad 13 and a second solder pad 14. First solder pad 13 is located on the side surface of main body 11 where first receiving groove 16 is disposed, while second solder pad 14 is located on the bottom wall of first receiving groove 16. Flexible circuit board 2 is located within first receiving groove 16 and is provided with a second solder pad 21 and a fourth solder pad 22. First solder pad 13 and second solder pad 21 are bonded together via metal wires 3, while third solder pad 14 and fourth solder pad 22 are connected using FOB welding technology. This allows flexible circuit board 2 to be housed within main body 11, thereby reducing the overall thickness of circuit board assembly 10. The specific connection structures of first solder pad 13 and second solder pad 21, third solder pad 14 and fourth solder pad 22, and chip 4 and flexible circuit board 2 are identical to those described in the previous embodiment and will not be further described here. In this embodiment, the first solder pad 13 is located outside the first receiving groove 16, that is, the first receiving groove 16 is only used to accommodate the flexible circuit board 2, which is beneficial to reducing the size of the first receiving groove 16 and reducing the impact of the groove on the printed circuit board 1, thereby improving the structural strength of the printed circuit board 1.

[0121] The circuit board assembly 10 further includes a packaging structure 5, which is fixed to a side surface of the main body 11 provided with a first receiving groove 16, and the first solder pad 13 is located within the packaging structure. Of course, at least a portion of the packaging structure 5 can also be filled in the first receiving groove 16, so that the packaging structure 5 can encapsulate the connection portion between the printed circuit board 1 and the flexible circuit board 2, protecting the connection portion between the printed circuit board 1 and the flexible circuit board 2 from the influence of the external environment, thereby improving the mechanical strength of the circuit board assembly 10, ensuring the reliability and stability of the circuit board assembly 10 in various environments, and thus helping to improve the service life of the electronic device 100. In addition, combined with Figure 24 As shown, in this embodiment, no chip or other devices are provided on the flexible circuit board 2 , so there is no need to provide a reinforcement structure on the flexible circuit board 2 .

[0122] Figure 25 This is a structural diagram of a circuit board assembly 10 provided in another embodiment of the present application, as shown in FIG. Figure 25As shown, circuit board assembly 10 includes a printed circuit board 1 and a flexible circuit board 2. Printed circuit board 1 comprises only a main body 11, with a first receiving groove 16 disposed on its surface. The bottom wall of first receiving groove 16 is provided with a first solder pad 13 and a third solder pad 14. Flexible circuit board 2 is located within first receiving groove 16 and is provided with a second solder pad 21 and a fourth solder pad 22. First solder pad 13 and second solder pad 21 are bonded together via metal wires 3, while third solder pad 14 and fourth solder pad 22 are connected using FOB welding technology. This allows flexible circuit board 2 to be housed within main body 11, thereby reducing the overall thickness of circuit board assembly 10. The specific connection structures of first solder pad 13 and second solder pad 21, third solder pad 14 and fourth solder pad 22, and chip 4 and flexible circuit board 2 are identical to those described in the previous embodiment and will not be further described here.

[0123] The circuit board assembly 10 also includes a packaging structure 5, which is filled in the first receiving groove 16. The first solder pad 13, the second solder pad 21, the third solder pad 14, and the fourth solder pad 22 are all located in the packaging structure 5. The packaging structure 5 is flush with the surface of the main body 11, so that the overall thickness of the circuit board assembly 10 is only the thickness of the main body 11, which minimizes the thickness of the circuit board assembly 10. By providing the packaging structure 5, the circuit board assembly 10 can be protected, the mechanical strength of the circuit board assembly 10 can be improved, and the reliability and stability of the circuit board assembly 10 in various environments can be ensured, which is conducive to improving the service life of the electronic device 100. In addition, combined with Figure 26 As shown, in this embodiment, no chip or other devices are provided on the flexible circuit board 2 , so there is no need to provide a reinforcement structure on the flexible circuit board 2 .

[0124] Figure 27 This is a top view of a flexible circuit board 2 provided in one embodiment of the present application, as shown in FIG. Figure 27 As shown, multiple second solder pads 21 are distributed in an array on the surface of the flexible circuit board 2. The array has a first side 2a and a second side 2b that are relatively distributed along the width direction Y of the flexible circuit board 2, and a third side 2c and a fourth side 2d that are relatively distributed along the length direction X of the flexible circuit board 2. At least two of the first side 2a, the second side 2b, the third side 2c, and the fourth side 2d are provided with fourth solder pads 22 to improve the stability of the solder connection between the flexible circuit board 2 and the printed circuit board 1. If the fourth solder pad 2 is provided on only one of the first side 2a, the second side 2b, the third side 2c, and the fourth side 2d, the flexible circuit board 2 is prone to movement or misalignment during actual use, thereby affecting the service life of the circuit board assembly 10.

[0125] Figure 28 This is a structural diagram of the second pad 21 provided in one embodiment of the present application, as shown in FIG. Figure 28As shown, in the array composed of multiple second solder pads 21, multiple rows of second solder pads 21 can be set along the length direction X of the flexible circuit board 2, specifically 2 rows, 3 rows, 4 rows, 5 rows or more, which can be designed according to the actual size and use requirements of the flexible circuit board 2. The embodiment of the present application does not limit this. The embodiment of the present application takes the arrangement of two rows of second solder pads 21 in the length direction X of the flexible circuit board 2 as an example to introduce the specific structure of the second solder pads 21. Figure 28 As shown, the plurality of second pads 21 are respectively connected to the plurality of first metal traces 25 inside the flexible circuit board 2. When the second pads 21 are provided in two rows, along the width direction X of the flexible circuit board 2, a second pad 21 of the second row is provided between the two second pads 21 of the first row, that is, the second pads 21 of the first row and the second pads 21 of the second row are staggered in the length direction Y of the flexible circuit board 2 to facilitate the wiring of the first metal traces 25. Of course, as Figure 29 As shown, when two rows of second solder pads 21 are provided, along the width direction X of the flexible circuit board 2, the second solder pads 21 of the first row may also be provided between the two second rows of second solder pads 21. This is not limited in the present embodiment. Since the second solder pads 21 do not require through holes, the size of the second solder pads 21 is relatively small, allowing a greater number of second solder pads 21 to be provided on the surface of the flexible circuit board 2. Specifically, along the width direction X of the second solder pads 21, the distance L1 between the centerline of any second solder pad 21 and the centerline of another adjacent second solder pad 21 should be 0.1 mm to 3.0 mm. Specifically, L1 can be 0.1 mm, 0.16 mm, 0.25 mm, 0.5 mm, 0.8 mm, 1 mm, 1.mm, 1.5 mm, 1.8 mm, 2 mm, 2.3 mm, 2.5 mm, 2.8 mm, or 3 mm, or other values ​​within the above range. This allows for a fine pitch arrangement of the second pads 21, which is beneficial for increasing the number of second pads 21 in the flexible circuit board 2 and the wiring density of the first metal traces 25. Table 1 below exemplarily illustrates specific data of other parameters of the second pads 21 in the embodiment of this application.

[0126]

[0127] Referring to Table 1, when the parameters of the second pads 21 and the first metal traces 25 meet the values ​​provided in Table 1, the circuit connection requirements between the flexible circuit board 2 and the printed circuit board 1 can be met, and the total number of second pads 21 and the wiring density of the first metal traces 25 on the flexible circuit board 2 can be increased, thereby improving the current flow capacity of the flexible circuit board 2, forming a multi-channel current flow between the printed circuit board 1 and the flexible circuit board 2, increasing the path current and achieving a cooling effect, thereby increasing the service life of the components in the circuit board assembly 10, and further contributing to increasing the service life of the electronic device.

[0128] Figure 30 This is a schematic diagram of the structure of the fourth pad 22 on the flexible circuit board 2 provided in an embodiment of the present application. Taking the flexible circuit board 2 having two rows of second pads 21 arranged in the longitudinal direction X and the fourth pad 22 arranged on the third side 2c as an example, the specific structure of the fourth pad 22 is introduced. Figure 30 As shown, the plurality of fourth pads 22 are respectively connected to the plurality of second metal traces 26 inside the flexible circuit board 2 . Table 2 below exemplarily shows specific data of other parameters of the fourth pads 22 in the embodiment of the present application.

[0129]

[0130] Referring to Table 2, when the parameters of the fourth pad 22 and the second metal trace 26 meet the values ​​provided in Table 2, it can not only meet the circuit connection requirements between the flexible circuit board 2 and the printed circuit board 1, but also help to improve the wiring density on the flexible circuit board 2, thereby improving the current flow capacity of the flexible circuit board 2.

[0131] The flexible circuit board 2 provided in the embodiment of the present application may specifically be a double-layer wiring structure with a thickness of 0.104 mm, or a three-layer wiring structure with a thickness of 0.138 mm, which is not limited in the embodiment of the present application. Figure 31 This is a schematic cross-sectional view of a flexible circuit board 2 provided in one embodiment of the present application. Figure 31 As shown, when the flexible circuit board 2 provided in the embodiment of the present application has a double-layer wiring structure, the flexible circuit board 2 is provided with a first electromagnetic shielding layer 201, a first cover layer 202, a first wiring layer 203, a base layer 204, a second wiring layer 205, a second cover layer 206, and a second electromagnetic shielding layer 207 in sequence along the thickness direction Z of the flexible circuit board 2. The first electromagnetic shielding layer 201 and the second electromagnetic shielding layer 207 are respectively provided on both surfaces of the flexible circuit board 2 along the thickness direction X to improve the electromagnetic shielding capability and signal interference resistance of the flexible circuit board 2. Depending on actual use requirements, only one of the first electromagnetic shielding layer 201 or the second electromagnetic shielding layer 207 may be provided. The first cover layer 202 and the second cover layer 203 respectively cover the surfaces of the first wiring layer 203 and the second wiring layer 205 to provide protection and insulation for the first wiring layer 203 and the second wiring layer 205. The fourth pad 22 passes through the first routing layer 203, the base material layer 204, and the second routing layer 205. The first electromagnetic shielding layer 201, the first cover layer 202, the second cover layer 206, and the second electromagnetic shielding layer 207 surrounding the fourth pad 22 need to be removed. In addition, the first routing layer 203 and the second routing layer 205 can also be connected by a through hole or a blind hole.

[0132] Table 3 below exemplarily shows the specific data of the specific materials and thicknesses of each layer structure of the flexible circuit board 2 in the embodiment of the present application.

[0133]

[0134] Referring to Table 3, when the flexible circuit board 2 serves as the first flexible circuit board 1051 connecting the main board 103 and the sub-board 104, an air gap region is required. The adhesive layers and EMI shielding film at the bend of the flexible circuit board 2 need to be removed to disperse stress at the bend, thereby improving the bendability of the flexible circuit board 2.

[0135] like Figure 32 As shown, in the first wiring layer 203, a first grounding line 203a and a first signal line 203b may be provided, which are insulated from each other. The first signal line 203b is used to form an electrical connection with an external electrical device to achieve data transmission. The width D1 of the first grounding line 203a, the width D2 of the first signal line 203b, and the spacing D3 between the first grounding line 203a and the first signal line 203b should satisfy the following conditions: D1>D2+D3, so as to reduce the resistance of the first grounding line 203a, improve the current carrying capacity of the first grounding line 203a, and reduce the interference of the first signal line 203b, thereby making the flexible circuit board 2 suitable for use in a circuit board assembly 10 with high current, high-speed signal, and high power. Similarly, as Figure 33 As shown, a second ground line 205a and a second signal line 205b may be provided in the second routing layer 205. The second signal line 205b is used to form an electrical connection with an external device to implement data transmission. The width D4 of the second ground line 205a, the width D5 of the second signal line 205b, and the spacing D6 between the second ground line 205a and the second signal line 205b should satisfy the following: D4>D5+D6.

[0136] Figure 34 This is a schematic cross-sectional view of a flexible circuit board 2 provided in another embodiment of the present application. Figure 34As shown, when the flexible circuit board 2 provided in the embodiment of the present application has a three-layer wiring structure, along the thickness direction Z of the flexible circuit board 2, the flexible circuit board 2 is provided with a first electromagnetic shielding layer 201, a first cover layer 202, a first wiring layer 203, a first substrate layer 204a, a third wiring layer 208, a second substrate layer 204b, a second wiring layer 205, a second cover layer 206, and a second electromagnetic shielding layer 207 in sequence. The materials and parameters of the first electromagnetic shielding layer 201, the first cover layer 202, the first wiring layer 203, the second wiring layer 205, the second cover layer 206, and the second electromagnetic shielding layer 207 can refer to the data in Table 3. The materials and parameters of the first substrate layer 204a and the second substrate layer 204b can also refer to the materials and parameters of the substrate layer 204 in Table 3, and the present embodiment does not limit this. The fourth pad 22 passes through the first routing layer 203, the first base material layer 204a, the third routing layer 208, the second base material layer 204b, and the second routing layer 205, and the first electromagnetic shielding layer 201, the first cover layer 202, the second cover layer 206, and the second electromagnetic shielding layer 207 surrounding the fourth pad 22 need to be removed. In addition, the first routing layer 203, the second routing layer 205, and the third routing layer 208 can also be connected by through holes or blind vias.

[0137] When the flexible circuit board 2 serves as the first flexible circuit board 1051 connecting the main board 103 and the sub-board 104, an air gap region is required. The adhesive layers and EMI shielding film at the bend of the flexible circuit board 2 need to be removed to disperse the stress at the bend of the flexible circuit board 2, thereby improving the bendability of the flexible circuit board 2.

[0138] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A circuit board assembly, characterized in that: include: A printed circuit board is provided with a first soldering pad and a third soldering pad; A flexible circuit board is provided with a second solder pad and a fourth solder pad, wherein the second solder pad is provided on at least one side surface of the flexible circuit board along the thickness direction of the flexible circuit board, and the second solder pad is connected to the first solder pad by metal wire bonding; The fourth pad is fixed to the third pad by welding, the fourth pad includes a through hole penetrating the flexible circuit board along the thickness direction of the flexible circuit board, and at least a portion of the solder point is located in the through hole; The flexible circuit board includes a plurality of second solder pads, and the plurality of second solder pads are distributed in an array; the array has a first side and a second side that are relatively distributed along the width direction of the flexible circuit board, and a third side and a fourth side that are relatively distributed along the length direction of the flexible circuit board, and at least two of the first side, the second side, the third side, and the fourth side are provided with the fourth solder pad; The printed circuit board is provided with a receiving groove, and the circuit board assembly further includes a chip and a reinforcement frame, at least a portion of the chip is located in the receiving groove, and along the thickness direction of the flexible circuit board, a side surface of the flexible circuit board facing the receiving groove is welded and fixed to the chip; Along the thickness direction of the flexible circuit board, the reinforcement frame is fixed to a surface of the flexible circuit board away from the chip, the reinforcement frame has a first accommodation space, and the second solder pad and the fourth solder pad are located in the first accommodation space; The circuit board assembly also includes a packaging structure, which is arranged on the printed circuit board. The first solder pad, the second solder pad, the metal lead, the third solder pad, the fourth solder pad, the chip and the reinforcement frame are all located in the packaging structure.

2. The circuit board assembly according to claim 1, wherein: The printed circuit board is provided with a first receiving groove, the flexible circuit board is welded and fixed to the bottom wall of the first receiving groove, and the receiving groove is provided on the bottom wall of the first receiving groove; Along the thickness direction of the flexible circuit board, the second pad is arranged on a side surface of the flexible circuit board away from the receiving groove.

3. The circuit board assembly according to claim 2, wherein: The first solder pad is disposed on the bottom wall of the first receiving groove.

4. The circuit board assembly according to claim 2, wherein: The packaging structure is filled in the first receiving groove.

5. The circuit board assembly according to claim 2, wherein: Along the thickness direction of the printed circuit board, the first solder pad is arranged on a side surface of the printed circuit board having the first receiving groove.

6. The circuit board assembly according to claim 5, wherein: The packaging structure is fixed on a side surface of the printed circuit board having the first receiving groove.

7. The circuit board assembly according to claim 1, wherein: Along the thickness direction of the flexible circuit board, the second pad is arranged on a surface of the flexible circuit board that is away from the printed circuit board.

8. The circuit board assembly according to claim 1, wherein: Along the thickness direction of the printed circuit board, the flexible circuit board is soldered and fixed on the side surface of the printed circuit board having the accommodating groove, and the first solder pad is arranged on the side surface of the printed circuit board having the accommodating groove.

9. The circuit board assembly according to claim 1, wherein: The circuit board assembly further includes an electronic component, which is fixed to the second soldering pad by welding.

10. The circuit board assembly according to claim 9, wherein: The packaging structure is fixed on a side surface of the printed circuit board having the receiving groove; The electronic component is located in the packaging structure.

11. The circuit board assembly according to claim 1, wherein: The flexible circuit board includes a plurality of second solder pads, and the plurality of second solder pads are distributed in an array; Along the width direction of the second pads, a distance between a center line of any second pad and a center line of another adjacent second pad is 0.1 mm to 3.0 mm.

12. A circuit board assembly, characterized in that: include: A printed circuit board comprises a main body and a connecting plate, wherein the connecting plate is provided with a first soldering pad and a third soldering pad; A flexible circuit board is provided with a second solder pad and a fourth solder pad, wherein the second solder pad is provided on at least one side surface of the flexible circuit board along the thickness direction of the flexible circuit board, and the second solder pad is connected to the first solder pad by metal wire bonding; Along the thickness direction of the connecting plate, one side surface of the connecting plate is welded and fixed to the main body, and the inner side of the other side surface of the connecting plate is welded and fixed to the outer side of the flexible circuit board via the third soldering pad and the fourth soldering pad; The fourth pad is fixed to the third pad by welding, the fourth pad includes a through hole penetrating the flexible circuit board along the thickness direction of the flexible circuit board, and at least a portion of the solder point is located in the through hole; Along the thickness direction of the connecting plate, the first pad is provided on a surface of the connecting plate away from the main body; The flexible circuit board includes a plurality of second solder pads, and the plurality of second solder pads are distributed in an array; the array has a first side and a second side that are oppositely distributed along the width direction of the flexible circuit board, and a third side and a fourth side that are oppositely distributed along the length direction of the flexible circuit board, and at least two of the first side, the second side, the third side, and the fourth side are provided with the fourth solder pads; The circuit board assembly further includes a chip and a reinforcement frame, and along the thickness direction of the flexible circuit board, a surface of the flexible circuit board facing the printed circuit board is welded and fixed to the chip; Along the thickness direction of the flexible circuit board, the reinforcement frame is fixed to a surface of the flexible circuit board away from the chip, the reinforcement frame has a first accommodation space, and the second solder pad and the fourth solder pad are located in the first accommodation space; The circuit board assembly also includes a packaging structure, which is arranged on the connecting board. The first solder pad, the second solder pad, the metal lead, the third solder pad, the fourth solder pad, the chip and the reinforcement frame are all located in the packaging structure.

13. The circuit board assembly according to claim 12, wherein: The circuit board assembly further includes a reinforcing piece, which is fixedly connected to a surface of the flexible circuit board on which the chip is provided, along a thickness direction of the flexible circuit board; The reinforcing piece is arranged around the circumference of the chip.

14. The circuit board assembly according to claim 12, wherein: The package structure includes a first sub-package structure and a second sub-package structure; The first sub-package structure is fixed on a side surface of the connection board having the first pad, and the first pad and the second pad are located in the first sub-package structure; A second accommodation space is formed between the chip, the connecting plate and the main body, and the second sub-package structure is filled in the second accommodation space.

15. The circuit board assembly according to claim 12, wherein: The flexible circuit board includes a plurality of second solder pads, and the plurality of second solder pads are distributed in an array; Along the width direction of the second pads, a distance between a center line of any second pad and a center line of another adjacent second pad is 0.1 mm to 3.0 mm.

16. An electronic device, characterized in that: A circuit board assembly comprising any one of claims 1-11, or a circuit board assembly comprising any one of claims 12-15.

17. The electronic device according to claim 16, wherein: The printed circuit board is a main board, the electronic device further comprises a camera module, and one end of the flexible circuit board away from the main board is connected to the camera module; Alternatively, the electronic device further includes a sound cavity module, and one end of the flexible circuit board away from the main board is connected to the sound cavity module.

18. The electronic device according to claim 16, wherein: The printed circuit board is a main board, and the electronic device further comprises a first shell, a second shell and a sub-board, wherein the main board and the sub-board are respectively arranged in the first shell and the second shell; The first shell and the second shell are connected via a rotating shaft, one end of the flexible circuit board is connected to the main board, and the other end of the flexible circuit board is connected to the sub-board via the first shell, the rotating shaft and the second shell.

19. The electronic device according to claim 16, wherein: The printed circuit board is a control board of the battery protection board; The electronic device further includes a mainboard, and one end of the flexible circuit board away from the control board is connected to the mainboard.

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