CN119095255A

CN119095255A - Circuit board assembly and electronic equipment

Info

Publication number: CN119095255A
Application number: CN202411571293.9A
Authority: CN
Inventors: 郭健强
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2024-11-06
Filing date: 2024-11-06
Publication date: 2024-12-06

Abstract

The present application relates to a circuit board assembly and an electronic device, the circuit board assembly includes a solder-fixed printed circuit board and a flexible circuit board, the printed circuit board being provided with a first solder pad. And a second bonding pad is arranged on at least one side surface of the flexible circuit board along the thickness direction of the flexible circuit board, and the second bonding pad is connected with the first bonding pad through metal wire bonding. The second bonding pad is connected with the first bonding pad in a bonding way, the second bonding pad does not need to be provided with a through hole structure, the number of holes in the flexible circuit board can be reduced, the structural strength of the flexible circuit board can be improved, the wiring density of the flexible circuit board and the number of bonding pads in the flexible circuit board can be improved, the through-flow capacity of the flexible circuit board is improved, multi-channel through-flow is formed between the printed circuit board and the flexible circuit board, the effect of cooling is achieved by improving the through-flow current, the service life of components in the circuit board assembly is prolonged, and the service life of electronic equipment is prolonged.

Description

Circuit board assembly and electronic equipment

Technical Field

The present application relates to the field of terminal devices, and in particular, to a circuit board assembly and an electronic device.

Background

Electronic devices (e.g., mobile terminals such as smartwatches, cell phones, notebook computers, etc.) are typically provided with a printed circuit board (Printed Circuit Board, PCB) and a flexible circuit board (Flexible Printed Circuit, FPC). At present, a FOB soldering technology (FPC on Board) is used to replace a Board-to-Board (BTB) to connect a printed circuit Board and a flexible circuit Board, so as to achieve miniaturization of an electronic device, but this connection mode needs to provide a through hole on the flexible circuit Board, which results in a reduced wiring density of the flexible circuit Board and affects the current-through capability of the flexible circuit Board.

Disclosure of Invention

An objective of an embodiment of the present application is to provide a circuit board assembly and an electronic device, so as to solve the problem that in the related art, a flexible circuit board has insufficient current-through capability due to too low wiring density.

In a first aspect, an embodiment of the present application provides a circuit board assembly, including a printed circuit board and a flexible circuit board, where the printed circuit board is provided with a first pad, the flexible circuit board is welded and fixed with the printed circuit board, and along a thickness direction of the flexible circuit board, at least one side surface of the flexible circuit board is provided with a second pad, and the second pad is connected with the first pad through metal wire bonding. The second bonding pad in this embodiment does not need to set up the through-hole structure, can reduce the trompil quantity on the flexible circuit board, not only can improve the structural strength of flexible circuit board, can also promote the wiring density of flexible circuit board and the bonding pad quantity on the flexible circuit board to improve the through-flow capacity of flexible circuit board, form multichannel through-flow between printed circuit board and flexible circuit board, thereby improve the effect that the passageway electric current reaches the cooling.

In one possible embodiment, the printed circuit board is provided with a first receiving groove, and the flexible circuit board is fixed to a bottom wall of the first receiving groove by soldering. The flexible circuit board in the embodiment can be accommodated in the printed circuit board, so that the structure of the circuit board assembly is more compact, and the effect of reducing the overall thickness of the circuit board assembly is achieved.

In one possible embodiment, the first bonding pad is disposed at a bottom wall of the first receiving groove. The metal leads in the embodiment are also all positioned in the first accommodating groove, so that the structure of the circuit board assembly is further compact.

In one possible embodiment, the bottom wall of the first receiving groove is provided with a second receiving groove. The circuit board assembly further comprises a chip, at least part of the chip is located in the second accommodating groove, and the flexible circuit board is welded and fixed with the chip along the thickness direction of the flexible circuit board, and faces to one side surface of the second accommodating groove. And the second bonding pad is arranged on one side surface of the flexible circuit board, which is far away from the second accommodating groove, along the thickness direction of the flexible circuit board. The flexible circuit board in this embodiment can realize two-sided cloth piece, has improved flexible circuit board's cloth piece ability, and through seting up the second holding tank in first holding tank moreover, can reduce the overall thickness of circuit board subassembly.

In one possible embodiment, the circuit board assembly further includes a package structure filled in the first receiving groove. In this embodiment, the mechanical strength of the circuit board assembly can be improved by the package structure, and the thickness of the circuit board assembly is not increased when the package structure is filled in the first accommodating groove.

In one possible embodiment, the first pad is disposed on a side surface of the printed circuit board having the first receiving groove in a thickness direction of the printed circuit board. In this embodiment, the first bonding pad is located outside the first accommodation groove, that is, the first accommodation groove is only used for accommodating the flexible circuit board, which is favorable for reducing the size of the first accommodation groove, reducing the influence of the slotting on the printed circuit board, and improving the structural strength of the printed circuit board.

In one possible embodiment, the circuit board assembly further includes a package structure fixed to a side surface of the printed circuit board having the first receiving groove. The first bonding pad is located in the packaging structure. In this embodiment, the packaging structure can encapsulate the connection part of the printed circuit board and the flexible circuit board, and protect the connection part of the printed circuit board and the flexible circuit board from external environment, thereby improving the mechanical strength of the circuit board assembly and ensuring the reliability and stability of the circuit board assembly in various environments.

In one possible implementation manner, the circuit board assembly further comprises a chip, wherein the flexible circuit board is welded and fixed with the chip along a thickness direction of the flexible circuit board, and the second bonding pad is arranged on a side surface of the flexible circuit board away from the printed circuit board along the thickness direction of the flexible circuit board. The flexible circuit board in the embodiment can realize double-sided piece arrangement, and the piece arrangement capacity of the flexible circuit board is improved.

In one possible implementation manner, the circuit board assembly further comprises a reinforcing frame, the reinforcing frame is fixed on one side surface of the flexible circuit board, which is far away from the chip, along the thickness direction of the flexible circuit board, the reinforcing frame is provided with a first accommodating space, and the second bonding pad is located in the first accommodating space. In this embodiment, the reinforcing frame can also pull the flexible circuit board from the position of second pad periphery when promoting the mechanical strength of flexible circuit board to keep the roughness of flexible circuit board, thereby promote the structural stability of flexible circuit board.

In one possible embodiment, the printed circuit board is provided with a third accommodation groove, at least part of the chip is accommodated in the third accommodation groove, the flexible circuit board is welded and fixed on one side surface of the printed circuit board with the third accommodation groove along the thickness direction of the printed circuit board, and the first bonding pad is arranged on one side surface of the printed circuit board with the third accommodation groove. In this embodiment, at least a portion of the chip can be located in the third accommodating groove, so that the structure of the circuit board assembly is more compact, and the effect of reducing the overall thickness of the circuit board assembly is achieved.

In one possible embodiment, the circuit board assembly further includes an electronic component, and the electronic component is soldered to the second pad. The double-sided cloth piece of the flexible circuit board is realized, the cloth piece density of the flexible circuit board is improved, and the connecting path of the electronic element and the flexible circuit board can be shortened, so that the structural compactness of the circuit board assembly is improved.

In one possible embodiment, the circuit board assembly further includes a package structure fixed to a side surface of the printed circuit board having the third receiving groove, the first pad, the second pad, and the electronic component being located within the package structure. In this embodiment, the packaging structure can form the protection to the circuit board subassembly, improves the mechanical strength of circuit board subassembly, ensures reliability and the stability of circuit board subassembly under various environment.

In one possible implementation manner, the printed circuit board includes a main body and a connecting plate, one side surface of the connecting plate is welded and fixed with the main body along the thickness direction of the connecting plate, the other side of the connecting plate is welded and fixed with the connecting plate, and the first bonding pad is arranged on one side surface of the connecting plate far away from the main body along the thickness direction of the connecting plate. In this embodiment, one side surface of the connection board is used to form an electrical connection with the main body, and the other side surface is used to form an electrical connection with the flexible circuit board, so as to realize conduction between the printed circuit board and the flexible circuit board.

In one possible implementation manner, the circuit board assembly further comprises a reinforcing member, wherein the reinforcing member is fixedly connected with one side surface of the flexible circuit board, on which the chip is arranged, in the thickness direction of the flexible circuit board, and the reinforcing member is circumferentially arranged around the chip. In this embodiment, the reinforcement member is used for reducing the risk of damage to the part of the structure of the flexible circuit board connected with the chip due to bending, which is beneficial to improving the mounting stability and reliability of the chip on the flexible circuit board.

In one possible implementation manner, the circuit board assembly further comprises a packaging structure, the packaging structure comprises a first sub-packaging structure and a second sub-packaging structure, the first sub-packaging structure is fixed on one side surface of the connecting plate with the first bonding pad, the first bonding pad and the second bonding pad are located in the first sub-packaging structure, a second accommodating space is formed among the chip, the connecting plate and the main body, and the second sub-packaging structure is filled in the second accommodating space. The first sub-packaging structure is used for packaging the connection part of the printed circuit board and the flexible circuit board, protecting the connection part of the printed circuit board and the flexible circuit board from the influence of external environment, and reducing the risk that the connection part of the printed circuit board and the flexible circuit board is subjected to physical damage or environmental corrosion. The second sub-packaging structure is filled in the second accommodating space and is used for packaging the chip and improving the connection stability and reliability between the chip and the flexible circuit board.

In one possible implementation manner, the flexible circuit board includes a plurality of the second pads, the plurality of second pads are distributed in an array, and a distance between a center line of any one of the second pads and a center line of another second pad adjacent thereto is 0.1mm-3.0mm along a width direction of the second pads. The embodiment can realize small-space arrangement of the second bonding pads, and is beneficial to improving the number and wiring density of the second bonding pads in the flexible circuit board.

In one possible implementation manner, the printed circuit board is further provided with a third bonding pad, the flexible circuit board is further provided with a fourth bonding pad, the fourth bonding pad and the third bonding pad are welded and fixed through a welding spot, the fourth bonding pad comprises a through hole penetrating through the flexible circuit board along the thickness direction of the flexible circuit board, and at least part of the welding spot is located in the through hole. In this embodiment, the third pad and the fourth pad are connected by adopting a welding technology, and the welding spot can be fixedly connected with the metal connection layer in the through hole and form conduction, so that the third pad and the fourth pad are fixedly welded and form electrical connection.

In one possible embodiment, the flexible circuit board includes a plurality of the second pads, the plurality of the second pads are distributed in an array, the array has a first side and a second side which are distributed oppositely along a width direction of the flexible circuit board, and a third side and a fourth side which are distributed oppositely along a 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 pads. In this embodiment, at least two of the first side, the second side, the third side and the fourth side are provided with the fourth bonding pad, so as to improve the stability of the welded connection between the flexible circuit board and the printed circuit board, if only one of the first side, the second side, the third side and the fourth side is provided with the fourth bonding pad, the flexible circuit board is easy to move or misplacement in the actual use process, and the service life of the circuit board assembly is affected.

In a second aspect, an embodiment of the present application provides an electronic device, including the circuit board assembly described in the above embodiments. The embodiment is beneficial to realizing miniaturization and light weight of the electronic equipment, and further beneficial to prolonging the service life of the electronic equipment.

In one possible implementation manner, the printed circuit board is a motherboard, the electronic device further includes a camera module, one end of the flexible circuit board away from the motherboard is connected with the camera module, or the electronic device further includes a sound cavity module, and one end of the flexible circuit board away from the motherboard is connected with the sound cavity module. In this embodiment, the data transmission capability between the motherboard and the camera module can be improved, and/or the data transmission capability between the motherboard and the sound cavity module can be improved.

In one possible implementation manner, the printed circuit board is a motherboard, the electronic device further includes a first shell, a second shell and an auxiliary board, the motherboard and the auxiliary board are respectively disposed in the first shell and the second shell, the first shell and the second shell are connected through a rotating shaft, one end of the flexible circuit board is connected with the motherboard, and the other end of the flexible circuit board is connected with the auxiliary board through the first shell, the rotating shaft and the second shell. In this embodiment, the data transmission capability between the main board and the auxiliary board can be improved, and the bending radius of the flexible circuit board can be reduced, so that the electronic device is light and thin.

In one possible implementation manner, the printed circuit board is a control board of a battery protection board, the electronic device further comprises a main board, and one end of the flexible circuit board away from the control board is connected with the main board. The embodiment is beneficial to reducing the area of the battery protection board, improving the quick charge power of the battery protection board and providing higher charge wattage for the battery protection board.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application as claimed.

Drawings

Fig. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present application;

Fig. 2 is a schematic structural diagram of an electronic device in a folded state according to another embodiment of the present application;

FIG. 3 is a schematic view of the electronic device in FIG. 2 in an unfolded state;

Fig. 4 is a schematic structural diagram of an electronic device in a folded state according to another embodiment of the present application;

FIG. 5 is a schematic view of the electronic device in FIG. 4 in an unfolded state;

FIG. 6 is a schematic diagram of the internal structure of the electronic device of FIG. 2;

FIG. 7 is a schematic diagram of a prior art solder connection between a flexible circuit board and a printed circuit board;

FIG. 8 is a schematic diagram of another related art solder connection between a flexible circuit board and a printed circuit board;

FIG. 9 is a schematic cross-sectional view of the first housing of FIG. 4;

FIG. 10 is a schematic diagram of a connection structure between the motherboard and the flexible circuit board in FIG. 9 in a first embodiment;

FIG. 11 is a schematic diagram showing a connection structure between the motherboard and the flexible circuit board in FIG. 9 in a second embodiment;

FIG. 12 is a schematic diagram showing a connection structure between the motherboard and the flexible circuit board in FIG. 9 in a third embodiment;

Fig. 13 is a schematic diagram of a connection structure between the motherboard and the flexible circuit board in fig. 9 in a fourth embodiment;

Fig. 14 is a schematic structural diagram of a circuit board assembly according to an embodiment of the present application;

FIG. 15 is a schematic view of a portion of the structure of FIG. 14;

FIG. 16 is a schematic diagram of a method of disposing the metal lead of FIG. 14;

FIG. 17 is a schematic view of a portion of the structure of FIG. 14 from another perspective;

FIGS. 18 (a) -18 (d) are process flow diagrams of a circuit board assembly according to one embodiment of the present application;

Fig. 19 is a schematic structural view of a circuit board assembly according to another embodiment of the present application;

FIG. 20 is a schematic view of a portion of the structure of FIG. 19 from another perspective;

Fig. 21 is a schematic structural view of a circuit board assembly according to another embodiment of the present application;

FIG. 22 is a schematic view of a portion of the structure of FIG. 21 from another perspective;

fig. 23 is a schematic structural view of a circuit board assembly according to another embodiment of the present application;

FIG. 24 is a schematic view of a portion of the structure of FIG. 23 from another perspective;

Fig. 25 is a schematic structural diagram of a circuit board assembly according to another embodiment of the present application;

FIG. 26 is a schematic view of a portion of the structure of FIG. 25 from another perspective;

fig. 27 is a schematic structural diagram of a flexible circuit board according to an embodiment of the application;

FIG. 28 is a layout diagram of a second bonding pad according to an embodiment of the present application;

FIG. 29 is a layout view of a second bonding pad according to another embodiment of the present application;

FIG. 30 is a schematic diagram of a fourth bonding pad according to an embodiment of the present application;

fig. 31 is a schematic cross-sectional view of a flexible circuit board according to an embodiment of the application;

Fig. 32 is a schematic cross-sectional view of a portion of the flexible circuit board of fig. 31 from another perspective;

FIG. 33 is a schematic cross-sectional view of a portion of the flexible circuit board of FIG. 31 from another perspective;

fig. 34 is a schematic cross-sectional view of a flexible circuit board according to another embodiment of the application.

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

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

In the description of the present application, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying any particular importance unless otherwise expressly specified or stated, the term "plurality" is intended to be broadly construed, such as "connected" or "fixed" in either a fixed or removable or integral or electrical connection, or may be directly or indirectly connected via an intervening medium. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the description of the present specification, it should be understood that the terms "upper", "lower", and the like used in the embodiments of the present application are described in terms of the angles shown in the drawings, and should not be construed as limiting the embodiments of the present application. In the context of this document, it will also be understood that when an element is referred to as being "on" or "under" another element, it can be directly on the other element or be indirectly on the other element through intervening elements.

Electronic devices (e.g., mobile terminals such as smartwatches, cell phones, notebook computers, etc.) are often provided with a printed circuit board (Printed Circuit Board, PCB) and a flexible circuit board (Flexible Printed Circuit, FPC), which in some cases need to be connected to each other to make electrical connection. For example, a printed circuit board may be used as a motherboard of a mobile phone, including but not limited to a processor, an antenna module, a bluetooth module, a WiFi module, a GPS module, a power supply, and a charging module or a screen display and operation module, and the flexible circuit board may be used to electrically connect a screen assembly of the mobile phone with the screen display and operation module on the motherboard, so that the screen assembly may implement display or operation functions. Or the flexible circuit board can also be used for realizing the electric connection between the main board and the battery protection board of the mobile phone. Or when the electronic device is a folding screen mobile phone, the flexible circuit board can span the rotating shaft to form electric connection between the main board of the mobile phone and the auxiliary board of the mobile phone. In the related art, a printed circuit Board and a flexible circuit Board are connected through a Board To Board (BTB), but the Board to Board connector itself has a large size, and occupies a large installation space, which is not beneficial to the layout of devices inside an electronic device, thereby affecting the realization of miniaturization of the electronic device.

The embodiment of the application provides electronic equipment, which can solve the technical problems. The electronic device may be an electronic device such as a smart watch, a cell phone, a tablet computer, a ultra-mobile personal computer (UMPC), a netbook, a cellular phone, a Personal Digital Assistant (PDA), an augmented reality (augmented reality, AR) device, a Virtual Reality (VR) device, an artificial intelligence (ARTIFICIAL INTELLIGENCE, AI) device, a wearable device, a vehicle-mounted device, a smart home device, and/or a smart city device. The embodiment of the application does not limit the specific form of the electronic device, and the electronic device is taken as a mobile phone for example for convenience of explanation.

Fig. 1 is a schematic structural diagram of an electronic device 100 according to an embodiment of the present application, where the electronic device 100 includes a display assembly 101 and a housing 102. The display assembly 101 may be understood as a screen of an electronic device having a display area for displaying image information, the display area of the display assembly 101 facing away from the housing 102.

Fig. 2 is a schematic structural diagram of an electronic device 100 in a folded state when the electronic device 100 is a double-folder according to another embodiment of the present application, where 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 shaft 1023, and the first housing 1021 and the second housing 1022 are rotatably connected by the first shaft 1023. When the first housing 1021 and the second housing 1022 are rotated along the rotation axis 1023 to the folded state, the display assembly 101 is also in the folded state, and the display assembly 101 is hidden between the first housing 1021 and the second housing 1022, that is, at this time, the display assembly 101 is in a position that is not viewable by the user.

Fig. 3 is a schematic structural diagram of the dual folder in an unfolded state, when the first casing 1021 and the second casing 1022 rotate along the first rotation axis 1023 back to the unfolded state, the first casing 1021 and the second casing 1022 are in the same plane, at this time, the display assembly 101 is also in the unfolded state, and the display assembly 101 can provide a larger display area, so as to bring good visual experience and operation experience to the user.

Fig. 4 is a schematic structural diagram of an electronic device 100 in a folded state when the electronic device 100 is a tri-folding machine according to another embodiment of the present application, where the housing 102 includes a first housing 1021, a second housing 1022, a third housing 1024, a first shaft 1023 and a second shaft 1025, the second housing 1022 is rotatably connected to the first housing 1021 through the first shaft 1023, and the second housing 1022 is rotatably connected to the third housing 1024 through the second 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, the portion of the displayed content is visible to the user, and another portion of the display assembly 101 is hidden between the second housing 1022 and the third housing 1024, the portion of the displayed content is not visible to the user.

Fig. 5 is a schematic view of the structure of the tri-folding machine in the unfolded state, in which the first casing 1021, the second casing 1022 and the third casing 1024 can rotate to the same plane along the first rotation shaft 1023 and the second rotation shaft 1025, respectively. When the electronic device 100 is in the unfolded state, the display assembly 101 is also in the unfolded state, and the display assembly 101 can provide a larger display area, so that a good visual experience and an operation experience are brought to the user.

It should be noted that the embodiment of the present application is not limited to the relative rotation directions of the first casing 1021, the second casing 1022 and the third casing 1023, and the structure of the electronic device 100 in fig. 2-5 is only an exemplary illustration of one implementation.

The internal structure of the electronic device 100 will be described below using the electronic device 100 as an example of a double folder.

As shown in fig. 6, the electronic device 100 includes a main board 103 and a sub-board 104, one of the main board 103 and the sub-board 104 is disposed in a first housing 1021, and the other is disposed in a second housing 1022, and the main board 103 is disposed in the first housing 1021 and the sub-board 104 is disposed in the second housing 1022. Integrated on motherboard 103 are chips or interfaces including, but not limited to, a System on a Chip (SOC) 1031, a universal flash memory storage Chip (universalflash storage, UFS) 1032, and a charging structure 1033. The main board 103 and the auxiliary board 104 are electrically connected through the first flexible circuit board 1051, and the first flexible circuit board 1051 can span the first rotating shaft 1023, and the spanning mode can specifically pass through the first rotating shaft 1023 or bypass the outer surface of the first rotating shaft 1023. The electronic device further includes a first battery 1061 and a second battery 1062, where one of the first battery 1061 and the second battery 1062 is disposed in the first housing 1021 and the other is disposed in the second housing 1022, and the embodiment of the application takes the first battery 1061 disposed in the first housing 1021 and the second battery 1062 disposed in the second housing 1022 as an example. The second battery 1062 is electrically connected to the sub-board 104 through the second flexible circuit board 1052. The first case 1021 is further provided therein with a battery protection board 107 electrically connected to the first battery 1061, and the battery protection board 107 generally includes functions of overcharge protection, overdischarge protection, overcurrent protection, short-circuit protection, and the like, so as to prevent the first battery 1061 from being damaged during use. The battery protection board 107 has a control board, and an electrical connection is made between the control board and the main board 103 through a third flexible circuit board 1053. Still be provided with camera module 108 and audio cavity module 109 in the first casing 1021, camera module 108 is the core part of cell-phone camera system, is responsible for catching the image and converts it into digital signal for realize the function of shooing of cell-phone, camera module 108 passes through fourth flexible circuit board 1054 with the mainboard and realizes the electricity and be connected. The cavity module 109 is a key component responsible for generating sound and is critical to providing a high quality audio experience, and the cavity module 109 is electrically connected to the motherboard through a fifth flexible circuit board 1055.

In the embodiments of the present application, all the structural layout diagrams are merely used to represent the composition, the general arrangement orientation, and the connection manner of the partial structures of the electronic device, and are not limited to specific structure types, positions, shapes, and the like. In other embodiments of the application, electronic device 100 may include more or fewer components than in FIG. 8, or certain components may be combined, or certain components may be split, or different arrangements of components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

The control boards on the main board 103, the auxiliary board 104 and the battery protection board 107 are all printed circuit boards, and in the related art, the printed circuit boards and the flexible circuit boards can be connected through board-to-board connectors, but the board-to-board connectors themselves are large in size, occupy large installation space, and are unfavorable for the layout of devices in the electronic equipment, so that the miniaturization of the electronic equipment is affected. Alternatively, as shown in fig. 7, the printed circuit board 010 and the flexible circuit board 020 may be stacked in the thickness direction Z of the printed circuit board 010 and electrically connected by soldering. The printed circuit board 010 is provided with a printed circuit board bonding pad 011, the flexible circuit board 020 is provided with a flexible circuit board bonding pad 021 corresponding to the position of the printed circuit board bonding pad 011, and the printed circuit board bonding pad 011 and the flexible circuit board bonding pad 021 are fixed through solder paste 012 and are electrically connected. 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 being connected is too large, and a large installation space is required to be occupied, which is not beneficial to the layout of devices in the electronic equipment, thereby affecting the realization of miniaturization of the electronic equipment. Moreover, when the thickness of the connection portion 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 is increased, and a larger bending space is required, so that the welding manner shown in fig. 7 is very unfavorable for the thinning of the folding machine.

In order to reduce the overall thickness of the printed circuit Board 010 after being connected to the flexible circuit Board 020, there is also a related art in which the printed circuit Board 010 is electrically connected to the flexible circuit Board 020 using a FOB soldering technology (FPC on Board). Specifically, as shown in fig. 8, a printed circuit board pad 011 is disposed on a printed circuit board 010, a flexible circuit board pad 021 corresponding to the position of the printed circuit board pad 011 is disposed on the flexible circuit board 020, the flexible circuit board pad 021 includes a tin-penetrating hole with a through hole structure and a connecting metal layer, and the inner wall of the tin-penetrating hole and the peripheries of the upper opening and the lower opening of the tin-penetrating hole are both provided with connecting metal layers. The heated solder paste 012 can enter the solder-penetrating holes by the extrusion of the flexible circuit board 020 and emerge from the side of the flexible circuit board 020 facing away from the printed circuit board 010. The solder paste 012 can be cured to connect and fix the printed circuit board 010 and the flexible circuit board 020, and the solder paste 012 can be electrically connected with the metal connection layer to realize the electrical connection between the printed circuit board 010 and the existing flexible circuit board 020. However, because the FOB soldering technology needs to provide a through hole on the flexible circuit board 020, it will affect the routing of the flexible circuit board 020, resulting in a reduction in the wiring density and the number of pads of the flexible circuit board 020, and further resulting in a poor current capacity of the flexible circuit board 020, which is not beneficial to data transmission between the flexible circuit board 020 and the electrical devices on the printed circuit board 010, and cannot meet the requirement that the current electronic device needs to improve the current capacity of the flexible circuit board.

The electronic device 100 provided by the embodiment of the application can improve the current passing capability of the flexible circuit board on the basis of reducing the overall thickness of the printed circuit board and the flexible circuit board after being fixedly connected. The internal structure of the electronic device 100 is described below with reference to the drawings.

As shown in fig. 9, the first casing 1021 includes a middle frame 1021a, a rear frame 1021b, and a decorative cover 1021c, and along a thickness direction Z of the electronic device 100, the display module 101 is fixedly connected to a side of the middle frame 1021a away from the rear frame 1021b, and a graphite layer 1011 and a first soaking plate 1012 are further disposed between the display module 101 and the middle frame 1021a, so as to improve heat dissipation capability of the electronic device 100. The main board 103 is located in a space surrounded by the middle frame 1021a, the rear case 1021b and the decorative cover 1021c, the main board 103 is fixedly connected with the middle frame 1021a through a fixing piece 1021d, a power management unit (Power Management Unit, PMU) 1034, a radio frequency power management integrated device (Radio Frequency Power MANAGEMENT INTEGRATED DEVICE, RFPMID) 1035 and a flexible circuit board 105 are installed on one side surface of the main board 103 facing the rear case 1021b along the thickness direction Z of the electronic device 100, a system-in-chip 1031 and a universal flash memory chip 1032 are installed on one side surface of the main board 103 facing the display assembly 101, other electric devices 1039 can be installed, and a low-power-consumption double data rate dynamic random access memory (Low Power Double Data Rate, LPDDR) 1036 is also installed on one side of the system-in-chip 1031 facing away from the main board 103. The power management unit 1034, the rf power management integrated device 1035, the system on a chip 1031, the universal flash memory chip 1032, and other electrical devices 1039 may be soldered to the motherboard 103 and form an electrical connection. The system on chip 1031 and the low power double data rate dynamic random access memory 1036 may also be solder-fixed and can form an electrical connection therebetween.

The first casing 1021 is further provided with a first shielding cover 1021e and a second shielding cover 1021f, the first shielding cover 1021e is fixed on one side surface of the main board 103 facing the rear casing 1021b, the first shielding cover 1021e and the main board 103 jointly enclose a first shielding cavity 1037, the power management unit 1034 and the radio frequency power management integrated device 1035 are located in the first shielding cavity 1037, and the first shielding cover 1021e can shield signals of the power management unit 1034 and the radio frequency power management integrated device 1035. The second shielding cover 1021f is fixed on a surface of the main board 103 facing the display component 101, the second shielding cover 1021f and the main board 103 together enclose a second shielding cavity 1038, and the system-on-chip 1031, the universal flash memory chip 1032, the low-power-consumption double-data-rate dynamic random access memory 1036 and other electrical devices 1039 are located in the second shielding cavity 1038, and the second shielding cover 1021f can perform signal shielding on the system-on-chip 1031, the universal flash memory chip 1032, the low-power-consumption double-data-rate dynamic random access memory 1036 and other electrical devices 1039. In addition, a thermal interface material (THERMAL INTERFACE MATERIAL, TIM) 1021g and a second soaking plate 1021h are further disposed between the second shielding case 1021f and the middle frame 1021a, so as to improve the heat dissipation capability of the electronic device 100. The flexible circuit board 105 is any one of a first flexible circuit board 1051, a third flexible circuit board 1053, a fourth flexible circuit board 1054, and a fifth flexible circuit board 1055.

As shown in fig. 10, when the flexible circuit board 105 is a 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, along the length direction X of the first flexible circuit board 1051. The first flexible circuit board 1051 and the main board 103 may be connected along a thickness direction Z of the first flexible circuit board 1051, and the first flexible circuit board 1051 and the sub-board 104 may be connected along the thickness direction Z of the first flexible circuit board 1051.

As shown in fig. 11, when the flexible circuit board 105 is the third flexible circuit board 1053, both ends of the third flexible circuit board 1053 are electrically connected to the main board 103 and the battery protection board 107, respectively, along the length direction Y of the third flexible circuit board 1053. The third flexible circuit board 1053 and the motherboard 103 may be soldered and fixed along the thickness direction Z of the third flexible circuit board 1053. The electronic device 100 further includes a first reinforcing portion 1053a, and the first reinforcing portion 1503a is fixed on a surface of the third flexible circuit board 1053 away from the battery protection board 107 along the thickness direction Z of the third flexible circuit board 1053, so as to improve the structural strength and the impact resistance of the third flexible circuit board 1053. The first reinforcing portion 1053a may be a metal reinforcement welded to the third flexible circuit board 1053, and the metal material has a better thermal conductivity, so that the thermal conductivity of the third flexible circuit board 1053 can be improved, and the third flexible circuit board 1053 is assisted to dissipate heat.

As shown in fig. 12, when the flexible circuit board 105 is a fourth flexible circuit board 1054, two ends of the fourth flexible circuit board 1054 are electrically connected to the main board 103 and the camera module 108, respectively, along the length direction Y of the fourth flexible circuit board 1054. The fourth flexible circuit board 1054 and the motherboard 103 may be connected along the thickness direction Z of the fourth flexible circuit board 1054, and the camera module 108 and the motherboard 103 are located on the same side of the fourth flexible circuit board 1054. The electronic device 100 further includes a second reinforcing portion 1054a, and the second reinforcing portion 1054a is fixed on a surface 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, so as to improve the structural strength and the impact resistance of the fourth flexible circuit board 1054. The second reinforcing portion 1054a may be a metal reinforcement welded to the fourth flexible circuit board 1054, and the metal material has a better thermal conductivity, so that the thermal conductivity of the fourth flexible circuit board 1054 can be improved, and the heat dissipation of the fourth flexible circuit board 1054 is assisted.

As shown in fig. 13, when the flexible circuit board 105 is the fifth flexible circuit board 1055, along the length direction Y of the fifth flexible circuit board 1055, two ends of the fifth flexible circuit board 1055 are electrically connected to the main board 103 and the acoustic cavity module 109, respectively. The fifth flexible circuit board 1055 and the motherboard 103 may be connected along the thickness direction Z of the fifth flexible circuit board 1055, and the sound cavity module 109 and the motherboard 103 are located on different sides of the fifth flexible circuit board 1055. The electronic device 100 further includes a third reinforcing portion 1055a, and the third reinforcing portion 1055a is fixed on a surface of the fifth flexible circuit board 1055 away from the acoustic cavity module 109 along the thickness direction Z of the fifth flexible circuit board 1055, so as to improve the structural strength and the impact resistance of the fifth flexible circuit board 1055. The third reinforcing portion 1055a may be a metal reinforcement welded to the fifth flexible circuit board 1055, and the metal material has a better thermal conductivity, so as to improve the thermal conductivity of the fifth flexible circuit board 1055 and help the heat dissipation of the fifth flexible circuit board 1055.

The embodiment of the application also provides a circuit board assembly 10, wherein the circuit board assembly 10 can be installed inside the electronic device 100, and the circuit board assembly 10 comprises a printed circuit board 1 and a flexible circuit board 2. The printed circuit board 1 may be specifically the motherboard 103 described above, and correspondingly, the flexible circuit board 2 may be specifically the flexible circuit board 105 described above, that is, the flexible circuit board 2 may 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. Or the printed circuit board 1 may be specifically the sub board 104 described above, and correspondingly the flexible circuit board 2 may be specifically the second flexible circuit board 1052. Or the printed circuit board 1 may be a control board on the battery protection board 107, and correspondingly, the flexible circuit board 2 may be a third flexible circuit board 1053.

The specific structure of the circuit board assembly 10 will be described below using the printed circuit board 1 as the motherboard 103 and the flexible circuit board 2 as the first flexible circuit board 1051 as an example.

Fig. 14 is a schematic structural diagram of a circuit board assembly 10 according to an embodiment of the present application, as shown in fig. 14, a printed circuit board 1 includes a main body 11 and a connecting board 12, and along a thickness direction Z of the connecting board 12, one side surface of the connecting board 12 is used for forming an electrical connection with the main body 11, and the other side surface is used for forming an electrical connection with a flexible circuit board 2, so as to realize conduction between the printed circuit board 1 and the flexible circuit board 2. Wherein, along the thickness direction Z of the connection board 12, a sixth pad 121 is disposed on a side surface of the connection board 12 facing the main body 11, a seventh pad 111 corresponding to the sixth pad 121 is disposed on a side surface of the main body 11 facing the connection board 12, and the main body 11 and the connection board 12 may be soldered and fixed by the sixth pad 121 and the seventh pad 111 to form an electrical connection. The specific shapes of the sixth pad 121 and the seventh pad 111 may be rectangular, square, circular, diamond or the like, which is not limited in the embodiment of the present application. In addition, the inside of the connection board 12 may be a double-layer wiring or a triple-layer wiring structure, and the connection board 12 may be provided with a through hole, a blind hole or a buried hole to realize electrical connection between different layers inside the connection board 12, which is not limited in the embodiment of the present application. The connection board 12 is provided with a first pad 13 and a third pad 14, the flexible circuit board 2 is provided with a second pad 21 and a fourth pad 22, the third pad 14 and the fourth pad 22 are soldered to form an electrical connection, and the first pad 13 and the second pad 21 are bonded to form an electrical connection through the metal lead 3.

First, a specific connection structure of the third pad 14 and the fourth pad 22 will be described, in which the third pad 14 and the fourth pad 22 may be connected by using a FOB soldering technique, and referring to fig. 15, the fourth pad 22 includes a through hole 221 penetrating through the flexible circuit board 2 in the thickness direction Z of the flexible circuit board 2, and a metal connection layer 222 is disposed on an inner wall of the through hole 221 and on an outer periphery of the upper and lower openings of the through hole 221. Along the thickness direction Z of the flexible circuit board 2, the third bonding pad 13 is disposed on a surface of the connecting plate 12 facing the flexible circuit board 2, the third bonding pad 13 is used for printing solder paste, the solder paste may include metallic tin and soldering flux, the solder paste melts after being heated, the through hole 221 of the fourth bonding pad 22 is aligned with the melted solder paste, then downward pressure is applied to the flexible circuit board 2, the melted solder paste can be extruded into the through hole 221, when the solder paste cools and solidifies, a welding spot 15 can be formed, and the welding spot 15 can be fixedly connected with the metallic connecting layer 222 in the through hole 221 and form conduction, so that the third bonding pad 14 and the fourth bonding pad 22 are welded and fixed and form electrical connection. In order to improve the soldering reliability and the electrical connection reliability of the third pad 14 and the fourth pad 22, the solder paste preferably completely penetrates the through hole 221 and overflows from the opening on one side of the through hole 221 away from the third pad 14 to be fixedly connected with the metal connection layer 222 on the periphery of the opening, that is, the structure of the solder joint 15 preferably can fill the through hole 221, and two ends of the solder joint 15 along the thickness direction Z of the flexible circuit board 2 can respectively cover the openings on two sides of the through hole 221.

Next, a specific connection structure of the first Bonding pad 13 and the second Bonding pad 21 will be described, wherein the first Bonding pad 13 is disposed on a side surface of the connecting board 12 facing the flexible circuit board 2 along the thickness direction Z of the flexible circuit board 2, the second Bonding pad 21 is disposed on a side surface of the flexible circuit board 2 far away from the connecting board 12, the first Bonding pad 13 and the second Bonding pad 21 are electrically connected by adopting a Wire Bonding (Wire Bonding) technology, and two ends of the metal lead 3 are respectively connected with the first Bonding pad 13 and the second Bonding pad 21 in a welding manner, so that the first Bonding pad 13 and the second Bonding pad 21 can be connected by the metal lead 3 in a Bonding manner. The material of the metal lead 3 may be specifically gold wire, aluminum wire or copper wire, which is not limited in the embodiment of the present application. The material of the second pad 21 is matched with that of the metal lead 3 to ensure that a certain intermetallic compound is formed between the metal lead 3 and the second pad 21, thereby ensuring the bonding 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 may be one of 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 may be one of an aluminum pad, a silver pad, or a nickel pad. When the metal lead 3 is a copper wire, the second bonding pad 21 may be a copper pad, and the metal lead 3 and the second bonding pad 21 may also be other materials, which is not limited in this embodiment of the present application.

Referring to fig. 16, taking the bonding connection between the first bonding pad 13 and the second bonding pad 21 by using the "thermosonic gold ball bonding method" (Thermosonic Gold Ball Wire Bonding) as an example, the bonding connection process between the first bonding pad 13 and the second bonding pad 21 and the metal wire 3 is described by first passing the gold wire 300 through a small hole in the center of the capillary 310, raising the temperature of the end of the gold wire 300, melting the gold wire 300 to form the gold ball 301, opening the clamp 320 for clamping the gold wire 300, applying heat, pressure and ultrasonic vibration to the capillary 310, and bonding the gold ball 301 to the fourth bonding pad 22 when the capillary 310 contacts the fourth bonding pad 22 to complete one-time ball bonding. Then, the capillary 310 is lifted up, after the gold wire balls 301 are formed again, heat, pressure and ultrasonic vibration are applied to the capillary 310, the gold wire balls 301 formed for the second time are rolled on the first bonding pads 13, and finally the gold wires 300 are disconnected through the clamp 320, so that the second bonding is completed, and both ends of the metal lead 3 can be respectively connected and fixed with the first bonding pads 13 and the second bonding pads 21. Of course, the gold wire ball 301 may be replaced by a wedge-shaped bonding structure, which is not limited in the embodiment of the present application.

Because the second bonding pad 21 is connected with the first bonding pad 13 in a bonding way, the second bonding pad 21 is not required to be provided with a through hole, the flexible circuit board 2 can achieve the effect of double-sided cloth, the chip 4 can be arranged on the surface of one side of the flexible circuit board 2 far away from the second bonding pad 21 along the thickness direction Z of the flexible circuit board 2, and the chip 4 and the flexible circuit board 2 can be welded and fixed through the solder 23 to form electric connection. The inner side of the connection board 12 should be soldered to the outer side of the flexible circuit board 2 through the third pad 14 and the fourth pad 22 along the thickness direction Z of the flexible circuit board 4 so as to provide a mounting space for the chip 4, and the positional relationship between the connection board 12 and the flexible circuit board 2 also facilitates the bonding connection between the first pad 13 and the second pad 21. In addition, a filling adhesive layer 41 can be further arranged between the chip 4 and the flexible circuit board 2, and the filling adhesive layer 41 can be Ultraviolet curing film adhesive (Ultraviolet curing film adhesive-curing FILM ADHESIVE, UF), which has higher adhesive strength, can bear certain mechanical stress, has certain flexibility, can absorb certain impact and vibration, and can improve the connection strength between the chip 4 and the flexible circuit board 2, so that the structural stability of the circuit board assembly 10 is improved.

The circuit board assembly 10 further comprises a reinforcing member 7, along the thickness direction Z of the flexible circuit board 2, the reinforcing member 7 is fixed on the surface of one side of the flexible circuit board 2, on which the chip 4 is arranged, the reinforcing member 7 can be specifically arranged circumferentially around the chip 4, so that the bending strength and the impact resistance of the part of the structure of the flexible circuit board 2 connected with the chip 4 are improved, the risk of damage to the part of the structure of the flexible circuit board 2 connected with the chip 4 due to bending is reduced, and the mounting stability and the mounting reliability of the chip 4 on the flexible circuit board 2 are improved. Meanwhile, the reinforcing piece 7 can also play a role in protecting the chip 4 along the circumferential direction of the chip 4, so that the impact resistance of the chip 4 is improved. The reinforcement member 7 may be welded to the fifth bonding pad 24 on the flexible circuit board 2, and the structure of the fifth bonding pad 24 may be the same as the second bonding pad 21, or may be a bonding pad with another structure, which is not limited in the embodiment of the present application, and of course, the reinforcement member 7 may also be fixedly connected to the flexible circuit board 2 by another connection method, which is not limited in the embodiment of the present application. The reinforcement member 7 may be a metal reinforcement, which can help the flexible circuit board 2 dissipate heat while improving the mechanical strength of the flexible circuit board 2, so as to improve the heat conductivity of the flexible circuit board 2.

The circuit board assembly 10 further includes a reinforcing frame 6, along the thickness direction Z of the flexible circuit board 2, the reinforcing frame 6 is fixed on a surface of the flexible circuit board 2 on which the second bonding pad 21 is disposed, and the reinforcing frame 6 may be specifically and fixedly connected to the flexible circuit board 2 by welding or gluing, which is not limited in the embodiment of the present application. As shown in fig. 17, the reinforcing frame 6 has a first accommodating space 61, and the second pad 21 and the fourth pad 22 are located in the first accommodating space 61, that is, the reinforcing frame 6 is disposed around the second pad 21 and the fourth pad 22, so that the reinforcing frame 6 can pull the flexible circuit board 2 from the positions of the outer circumferences of the second pad 21 and the fourth pad 22 while improving the mechanical strength of the flexible circuit board 2, so as to maintain the flatness of the flexible circuit board 2, thereby improving the structural stability of the flexible circuit board 2. In order to ensure the reinforcing effect of the reinforcing frame 6 on the flexible circuit board 2 and not occupy too much space on the surface of the flexible circuit board 2, the width of the reinforcing frame 6 may be 0.1mm-1mm, specifically 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm, or may be other values within the above range, which is limited by the embodiment of the present application. In addition, the material of the reinforcing frame 6 may be one of a metal material, a plastic material, or a mixture of metal and plastic, which is not limited in the embodiment of the present application.

The circuit board assembly 10 further comprises a package structure 5, the package structure 5 comprising a first sub-package structure 51 and a second sub-package structure 52. The first sub-packaging structure 51 is fixed on the surface of one side of the connecting plate 12 with the first bonding pad 13 and the third bonding pad 14, the first bonding pad 13, the second bonding pad 21, the third bonding pad 14 and the fourth bonding pad 22 are all positioned in the first sub-packaging structure 51, the first sub-packaging structure 51 is used for packaging the connection part of the printed circuit board 1 and the flexible circuit board 2, the connection part of the printed circuit board 1 and the flexible circuit board 2 is protected from the external environment, and the risk that the connection part of the printed circuit board 1 and the flexible circuit board 2 is physically damaged or corroded by the environment is reduced. A second accommodating space 18 is formed among the chip 4, the connecting plate 12 and the main body 11, a second sub-packaging structure 52 is filled in the second accommodating space 18, and the second sub-packaging structure 52 is used for realizing packaging of the chip 4 and improving connection stability and reliability between the chip 4 and the flexible circuit board 2. Therefore, the package 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 being beneficial to prolonging the service life of the electronic device 100. Specifically, the package structure 5 may be manufactured by a Molding process (Molding), that is, a molten material (such as plastic, resin, metal, etc.) is injected into a pre-designed mold, and after the material is cooled and solidified, the package structure 5 of a desired shape can be formed. Of course, the package structure 5 may be manufactured by other processes, which is not limited in the embodiment of the present application.

In summary, in the circuit board assembly 10 provided in the foregoing embodiment, the printed circuit board 1 and the flexible circuit board 2 are connected in a manner of combining the FOB welding technology and the wire bonding technology, which is favorable 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 being favorable to realizing miniaturization and thinness of the electronic device 100, meanwhile, since the second bonding 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, not only the structural strength of the flexible circuit board 2 can be improved, but also the wiring density of the flexible circuit board 2 and the number of bonding pads on the flexible circuit board 2 can be improved, thereby improving the through-flow capability of the flexible circuit board 2, forming a multi-channel through-flow between the printed circuit board 1 and the flexible circuit board 2, and improving the path current so as to achieve the effect of reducing the temperature, so as to improve the service life of components in the circuit board assembly 10, and further be favorable to improving the service life of the electronic device.

It should be noted that, in fig. 10 to 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 only schematic structures, and are not limited to specific structures and shapes.

The application also provides a processing method of the circuit board assembly 10, which is used for processing and producing the circuit board assembly 10 in the embodiment. Fig. 18 (a) -18 (d) are schematic flow diagrams of the processing method, and referring to fig. 18 (a) -18 (d), the processing method specifically includes:

step S1, providing a flexible circuit board 2 provided with second pads 21 and fourth pads 22.

Step S2, fixing the reinforcing frame 6 on the side surface of the flexible circuit board 2 provided with the second bonding pads 21 along the thickness direction Z of the flexible circuit board 2.

In this step, the reinforcing frame 6 is first mounted on the flexible circuit board 2 to ensure the flatness of the flexible circuit board 2, so as to facilitate subsequent processing.

Step S3, the chip 4 and the reinforcing member 7 are welded on the surface of the side of the flexible circuit board 2 away from the second bonding pad 21 along the thickness direction Z of the flexible circuit board 2.

As shown in fig. 18 (a), in this step, the side surface of the flexible circuit board 2 on which the second pads 21 are provided may be placed downward on the first supporting jig 200. Then, a cover plate tool 210 is placed on the upward side surface of the flexible circuit board 2 to press the flexible circuit board 2 against the supporting tool 200, thereby preventing the flexible circuit board 2 from being displaced. The chip 4 and the reinforcing member 7 are soldered on the upwardly facing side surface of the flexible circuit board 2 through the solder 23 and the fifth bonding pad 24, respectively, to complete the connection of the chip 4 and the flexible circuit board 2 and to improve the mechanical strength of the flexible circuit board 2.

In step S4, a dispensing curing process is performed between the chip 4 and the flexible circuit board 2 along the thickness direction Z of the flexible circuit board 2 to form a filler layer 41.

As shown in fig. 18 (b), in this step, the ultraviolet curing film adhesive may be filled between the chip 4 and the flexible circuit board 2 in a dispensing manner, then the dispensing portion is irradiated by using an ultraviolet light source, the filling adhesive layer 41 may be formed after the ultraviolet curing film adhesive is cured, and the filling adhesive layer 41 may not only promote the connection effect between the chip 4 and the flexible circuit board 2, but also absorb the external impact and vibration to a certain extent, so as to protect the chip 4. In addition, the ultraviolet curing film adhesive has the characteristic of quick curing, and is beneficial to improving the processing efficiency of the circuit board assembly 10.

Step S5, providing a connection board 12 provided with a first bonding pad 13 and a second bonding pad 14, and welding and fixing a third bonding pad 14 on the connection board 12 and a fourth bonding pad 22 on the flexible circuit board 2 through a welding spot 15, so that at least part of the welding spot 15 is positioned in the through hole 221.

In this step, the connecting board 12 and the flexible circuit board 2 are welded into a whole by using the FOB welding technology, so as to achieve the fixed connection and the electrical connection of the connecting board 12 and the flexible circuit board 2, and simultaneously ensure that the thickness of the whole formed by the connecting board 12 and the flexible circuit board 2 is minimized.

Step S6, the first bonding pads 13 on the connecting plate 12 and the second bonding pads 21 on the flexible circuit board 2 are connected through the metal lead 3 in a bonding mode.

As shown in fig. 18 (c), the whole body formed by the connection board 12 and the flexible circuit board 2 is moved onto the second supporting fixture 220 so that the chip 4 is placed downward and supported by the second supporting fixture 220, and the side surface of the connection board 12 provided with the first bonding pad 13 and the side surface of the flexible circuit board 2 provided with the second bonding pad 21 are placed toward each other so that the first bonding pad 13 and the second bonding pad 21 are bonded.

In step S7, a packaging process is performed on a side of the connection board 12 facing the flexible circuit board 2 along the thickness direction Z of the connection board 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 within the package structure 5.

As shown in fig. 18 (d), in this step, the integrated flexible circuit board 2 and the connection board 12 may be moved onto the third supporting tool 230, and then the first package structure 51 and the second package structure 52 may be formed simultaneously by a molding process, so as to form reliable protection for the connection portion between the flexible circuit board 2 and the connection board 12.

And S8, welding and fixing the main body 11 and the surface of the side, far away from the flexible circuit board 2, of the connecting plate 12 along the thickness direction Z of the connecting plate 12.

In this step, the flexible circuit board 2 and the connecting board 12 which are integrally connected and packaged are moved to the upper side of the main body 11, and the connecting board 12 is welded on the surface of the main body 11, so as to complete the assembly of the circuit board assembly 10, and finally, the circuit board assembly 10 with small thickness, high reliability and large through-flow capacity is obtained.

Fig. 19 is a schematic structural view of a circuit board assembly 10 according to another embodiment of the present application, and as shown in fig. 19, the circuit board assembly 10 includes a printed circuit board 1, a flexible circuit board 2 and a chip 4. The printed circuit board 1 only comprises a main body 11, a first bonding pad 13 and a third bonding pad 14 are arranged on the surface of the main body 11, a second bonding pad 21 and a fourth bonding pad 22 are arranged on the flexible circuit board 2, the first bonding pad 13 and the second bonding pad 21 are connected through a metal lead 3 in a bonding mode, and the third bonding pad 14 and the fourth bonding pad 22 are connected through a FOB welding technology. The main body 11 is provided with the first bonding pad 13 and the third bonding pad 14, the side surface is also provided with the third accommodation groove 17, the chip 4 is welded on the side surface of the flexible circuit board 2 facing the main body 11, and at least part of the chip 4 can be positioned in the third accommodation groove 17, so that the structure of the circuit board assembly 10 is more compact, and the effect of reducing the overall thickness of the circuit board assembly 10 is achieved. The specific connection structure of the first pad 13 and the second pad 21, the specific connection structure of the third pad 14 and the fourth pad 22, and the specific connection structure of the chip 4 and the flexible circuit board 2 are the same as those in the above embodiment, and will not be described here again.

The circuit board assembly 10 further includes a reinforcing frame 6, along a thickness direction Z of the flexible circuit board 2, the reinforcing frame 6 is fixed to a side surface of the flexible circuit board 2 where the second bonding pad 21 is provided, and the reinforcing frame 6 is used for maintaining flatness of the flexible circuit board 2, thereby improving structural stability of the flexible circuit board 2. In addition, in this embodiment, since the flexible circuit board 2 is directly welded and fixed to the main body 11, and the chip 4 is located in the third accommodating groove 17, the flexible circuit board 2 can be sufficiently supported, and there is no need to set other reinforcing structures on a side surface of the flexible circuit board 2 where the chip 4 is disposed, which is beneficial to simplifying the structure of the circuit board assembly 10 and improving the processing efficiency of the circuit board assembly 10.

The circuit board assembly 10 further includes an electronic component 8, as shown in fig. 20, where the electronic component 8 includes, but is not limited to, one of a capacitor, a resistor, and an inductor, and the electronic component 8 is fixed on the flexible circuit board 2, and may be specifically welded and fixed on the second bonding pad 21, that is, the electronic component 8 and the chip 4 are respectively disposed on two opposite surfaces of the flexible circuit board 2, so that a double-sided fabric of the flexible circuit board 2 is achieved, a fabric density of the flexible circuit board 2 is improved, and a connection path between the electronic component 8 and the flexible circuit board 2 can be shortened, so as to improve a structural compactness of the circuit board assembly 10. The specific number of the electronic components 8 is not limited in the embodiment of the present application, and may be one or more.

The circuit board assembly 10 further comprises a packaging structure 5, the packaging structure 5 is fixed on the surface of one side of the main body 1 with the third accommodating groove 17, the first bonding pad 13, the second bonding pad 21, the third bonding pad 14, the fourth bonding pad 22 and the electronic element 8 are all located in the packaging structure 5, at least part of the packaging structure 5 can be filled in the third accommodating groove 17 to protect the chip 4, therefore, the packaging structure 5 can protect the circuit board assembly 10, the mechanical strength of the circuit board assembly 10 is improved, the reliability and stability of the circuit board assembly 10 under various environments are ensured, and the service life of the electronic device 100 is prolonged.

Fig. 21 is a schematic structural diagram of a circuit board assembly 10 according to another embodiment of the present application, and as shown in fig. 21, the circuit board assembly 10 includes a printed circuit board 1, a flexible circuit board 2 and a chip 4. The printed circuit board 1 includes only the main body 11, the main body 11 is provided with the first accommodating groove 16, and the bottom wall of the first accommodating groove 16 is provided with the first pad 13 and the third pad 14. The flexible circuit board 2 is located in the first accommodating groove 16, the flexible circuit board 2 is provided with a second bonding pad 21 and a fourth bonding pad 22, the first bonding pad 13 and the second bonding pad 21 are connected through the metal lead 3 in a bonding mode, the third bonding pad 14 and the fourth bonding pad 22 are connected through the FOB welding technology, and namely the flexible circuit board 2 can be accommodated in the main body 11. The bottom wall of the first accommodating groove 16 is further provided with a second accommodating groove 161, the chip 4 is welded on one side surface of the flexible circuit board 2 facing the second accommodating groove 161, and at least part of the chip 4 can be located in the second accommodating groove 161, so that the structure of the circuit board assembly 10 is further compact, and the effect of reducing the overall thickness of the circuit board assembly 10 is achieved. The specific connection structure of the first pad 13 and the second pad 21, the specific connection structure of the third pad 14 and the fourth pad 22, and the specific connection structure of the chip 4 and the flexible circuit board 2 are the same as those in the above embodiment, and will not be described here again.

The circuit board assembly 10 further includes a reinforcing frame 6, as shown in fig. 22, along a thickness direction Z of the flexible circuit board 2, the reinforcing frame 6 is fixed to a side surface of the flexible circuit board 2 where the second bonding pad 21 is disposed, and the reinforcing frame 6 is used for maintaining flatness of the flexible circuit board 2, thereby improving structural stability of the flexible circuit board 2. In addition, the flexible circuit board 2 in this embodiment can be sufficiently supported, and other reinforcing structures do not need to be arranged on the surface of the side, on which the chip 4 is arranged, of the flexible circuit board 2, so that the structure of the circuit board assembly 10 is simplified, and the processing efficiency of the circuit board assembly 10 is improved.

The circuit board assembly 10 further comprises a packaging structure 5, the packaging structure 5 is filled in the first accommodating groove 16, the first bonding pad 13, the second bonding pad 21, the third bonding pad 14 and the fourth bonding pad 22 are all located in the packaging structure 5, and 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, and the thickness of the circuit board assembly 10 is reduced to the greatest extent. In addition, at least part of the packaging structure 5 can be filled in the second accommodating groove 161 to protect the chip 4, and the packaging structure 5 can protect the circuit board assembly 10, so that the mechanical strength of the circuit board assembly 10 is improved, the reliability and stability of the circuit board assembly 10 in various environments are ensured, and the service life of the electronic device 100 is prolonged.

Fig. 23 is a schematic structural view of a circuit board assembly 10 according to another embodiment of the present application, and as shown in fig. 23, the circuit board assembly 10 includes a printed circuit board 1 and a flexible circuit board 2. The printed circuit board 1 includes only the main body 11, the surface of the main body 11 is provided with the first accommodation groove 16, the main body 11 is further provided with the first bonding pad 13 and the second bonding pad 14, the first bonding pad 13 is located on the surface of the side of the main body 11 provided with the first accommodation groove 16, and the second bonding pad 14 is located on the bottom wall of the first accommodation groove 16. The flexible circuit board 2 is located in the first accommodating groove 16, the flexible circuit board 2 is provided with a second bonding pad 21 and a fourth bonding pad 22, the first bonding pad 13 is connected with the second bonding pad 21 through the metal lead 3 in a bonding manner, the third bonding pad 14 is connected with the fourth bonding pad 22 through the FOB welding technology, namely, the flexible circuit board 2 can be accommodated in the main body 11, and the effect of reducing the overall thickness of the circuit board assembly 10 is achieved. The specific connection structure of the first pad 13 and the second pad 21, the specific connection structure of the third pad 14 and the fourth pad 22, and the specific connection structure of the chip 4 and the flexible circuit board 2 are the same as those in the above embodiment, and will not be described here again. In this embodiment, the first bonding pad 13 is located outside the first accommodating groove 16, that is, the first accommodating groove 16 is only used for accommodating the flexible circuit board 2, which is favorable for reducing the size of the first accommodating groove 16, reducing the influence of the slot on the printed circuit board 1, and thus improving the structural strength of the printed circuit board 1.

The circuit board assembly 10 further includes a package structure 5, and the package structure 5 is fixed on a side surface of the main body 11 where the first receiving groove 16 is provided, and the first pads 13 are located in the package structure. Of course, at least part of the packaging structure 5 may be filled in the first accommodating groove 16, so that the packaging structure 5 can package the connection part of the printed circuit board 1 and the flexible circuit board 2, and protect the connection part of the printed circuit board 1 and the flexible circuit board 2 from external environment, thereby improving the mechanical strength of the circuit board assembly 10, ensuring the reliability and stability of the circuit board assembly 10 under various environments, and further being beneficial to improving the service life of the electronic device 100. Further, as shown in fig. 24, no chip or other device is provided on the flexible circuit board 2 in the present embodiment, and therefore, there is no need to provide a reinforcing structure on the flexible circuit board 2.

Fig. 25 is a schematic structural view of a circuit board assembly 10 according to another embodiment of the present application, and as shown in fig. 25, the circuit board assembly 10 includes a printed circuit board 1 and a flexible circuit board 2. The printed circuit board 1 includes only the main body 11, the surface of the main body 11 is provided with the first receiving groove 16, and the bottom wall of the first receiving groove 16 is provided with the first pad 13 and the third pad 14. The flexible circuit board 2 is located in the first accommodating groove 16, the flexible circuit board 2 is provided with a second bonding pad 21 and a fourth bonding pad 22, the first bonding pad 13 is connected with the second bonding pad 21 through the metal lead 3 in a bonding manner, the third bonding pad 14 is connected with the fourth bonding pad 22 through the FOB welding technology, namely, the flexible circuit board 2 can be accommodated in the main body 11, and the effect of reducing the overall thickness of the circuit board assembly 10 is achieved. The specific connection structure of the first pad 13 and the second pad 21, the specific connection structure of the third pad 14 and the fourth pad 22, and the specific connection structure of the chip 4 and the flexible circuit board 2 are the same as those in the above embodiment, and will not be described here again.

The circuit board assembly 10 further comprises a packaging structure 5, the packaging structure 5 is filled in the first accommodating groove 16, the first bonding pad 13, the second bonding pad 21, the third bonding pad 14 and the fourth bonding pad 22 are all located in the packaging structure 5, and 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, and the thickness of the circuit board assembly 10 is reduced to the greatest extent. The packaging structure 5 is arranged to protect the circuit board assembly 10, so that the mechanical strength of the circuit board assembly 10 is improved, the reliability and stability of the circuit board assembly 10 in various environments are ensured, and the service life of the electronic equipment 100 is prolonged. In addition, as shown in fig. 26, no chip or other device is provided on the flexible circuit board 2 in the present embodiment, and therefore, there is no need to provide a reinforcing structure on the flexible circuit board 2.

Fig. 27 is a top view of a flexible circuit board 2 according to an embodiment of the present application, as shown in fig. 27, a plurality of second pads 21 are distributed on a surface of the flexible circuit board 2 in an array, where the array has a first side 2a and a second side 2b that are relatively distributed along a width direction Y of the flexible circuit board 2 and a third side 2c and a fourth side 2d that are relatively distributed along a 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 pads 22 to improve the stability of the soldering connection between the flexible circuit board 2 and the printed circuit board 1, and if only one of the first side 2a, the second side 2b, the third side 2c and the fourth side 2d is provided with the fourth pads 2, the flexible circuit board 2 is easy to move or shift during actual use, which affects the service life of the circuit board assembly 10.

Fig. 28 is a schematic structural diagram of a second bonding pad 21 according to an embodiment of the present application, as shown in fig. 28, in an array formed by a plurality of second bonding pads 21, a plurality of rows of second bonding pads 21 may be disposed along a length direction X of the flexible circuit board 2, specifically, may be 2 rows, 3 rows, 4 rows, 5 rows or more, and may be designed according to an actual size and a usage requirement of the flexible circuit board 2. In the embodiment of the present application, two rows of second pads 21 are disposed in the length direction X of the flexible circuit board 2, and a specific structure of the second pads 21 will be described. As shown in fig. 28, the plurality of second pads 21 are respectively connected with the plurality of first metal traces 25 inside the flexible circuit board 2, when two rows of second pads 21 are disposed, one second row of second pads 21 is disposed between the two first rows of second pads 21 along the width direction X of the flexible circuit board 2, that is, the first row of second pads 21 and the second row of second pads 21 are disposed in a staggered manner in the length direction Y of the flexible circuit board 2, so that the first metal traces 25 can be conveniently routed. Of course, as shown in fig. 29, when two rows of the second pads 21 are provided, the first row of the second pads 21 may be provided between the two second rows of the second pads 21 along the width direction X of the flexible circuit board 2, which is not limited in the embodiment of the present application. Since the second pads 21 do not need to be provided with through holes, the size of the second pads 21 is relatively small, so that a larger number of second pads 21 can be provided on the surface of the flexible circuit board 2. Wherein, the distance L1 between the center line of any one of the second pads 21 and the center line of another second pad 21 adjacent thereto in the width direction X of the second pad 21 should be 0.1mm to 3.0mm, L1 may be specifically 0.1mm, 0.16mm, 0.25mm, 0.5mm, 0.8mm, 1mm, 1.mm, 1.5mm, 1.8mm, 2mm, 2.3mm, 2.5mm, 2.8mm or 3mm, and may be other values within the above range. To realize the small-pitch arrangement of the second pads 21, the number of the second pads 21 and the wiring density of the first metal wirings 25 in the flexible circuit board 2 are advantageously increased. Further, table 1 below exemplarily shows specific data of other parameters of the second pad 21 in the embodiment of the present application.

Referring to table 1, when the parameters of the second pads 21 and the first metal traces 25 satisfy the values provided in table 1, not only the circuit connection requirements between the flexible circuit board 2 and the printed circuit board 1 can be satisfied, but also the total number of the second pads 21 and the wiring density of the first metal traces 25 on the flexible circuit board 2 can be improved, thereby improving the through-flow capacity of the flexible circuit board 2, forming a multi-channel through-flow between the printed circuit board 1 and the flexible circuit board 2, improving the through-flow so as to achieve the effect of cooling, so as to improve the service life of components in the circuit board assembly 10, and further be beneficial to improving the service life of electronic equipment.

Fig. 30 is a schematic structural diagram of a fourth pad 22 on a flexible circuit board 2 according to an embodiment of the present application, and a specific structure of the fourth pad 22 is described taking two rows of second pads 21 disposed on a length direction X of the flexible circuit board 2 and the fourth pad 22 disposed on a third side 2c as an example. As shown in fig. 30, the plurality of fourth pads 22 are respectively connected to the plurality of second metal traces 26 inside the flexible circuit board 2, and the following table 2 exemplarily shows specific data of other parameters of the fourth pads 22 in the embodiment of the present application.

Referring to table 2, when the parameters of the fourth pad 22 and the second metal trace 26 satisfy the values provided in table 2, it is beneficial to not only satisfy the circuit connection requirement between the flexible circuit board 2 and the printed circuit board 1, but also promote the wiring density on the flexible circuit board 2, thereby improving the through-flow capability of the flexible circuit board 2.

The flexible circuit board 2 provided by the embodiment of the application may be a double-layer wiring structure with a thickness of 0.104mm or a three-layer wiring structure with a thickness of 0.138mm, which is not limited in the embodiment of the application. Fig. 31 is a schematic cross-sectional structure of a flexible circuit board 2 according to an embodiment of the present application, and as shown in fig. 31, when the flexible circuit board 2 according to the embodiment of the present application has a double-layer wiring structure, the flexible circuit board 2 is sequentially provided with a first electromagnetic shielding layer 201, a first cover layer 202, a first wiring layer 203, a base material layer 204, a second wiring layer 205, a second cover layer 206, and a second electromagnetic shielding layer 207 along a thickness direction Z of the flexible circuit board 2. The first electromagnetic shielding layer 201 and the second electromagnetic shielding layer 207 are respectively disposed on two surfaces of the flexible circuit board 2 along the thickness direction X thereof, for improving electromagnetic shielding capability and signal anti-interference capability of the flexible circuit board 2, and only one of the first electromagnetic shielding layer 201 and the second electromagnetic shielding layer 207 may be disposed according to actual use requirements. The first cover layer 202 and the second cover layer 203 are respectively covered on the surfaces of the first wiring layer 203 and the second wiring layer 205, and are used for protecting and insulating the first wiring layer 203 and the second wiring layer 205. The fourth pad 22 penetrates through the first wiring layer 203, the base material layer 204 and the second wiring 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 around the fourth pad 22 need to be removed. In addition, the connection between the first wiring layer 203 and the second wiring layer 205 may be realized by a via or a blind via.

Table 3 below exemplarily shows specific materials of the respective layer structures of the flexible circuit board 2 and specific data of thicknesses thereof in the embodiments of the present application.

Referring to table 3, when the flexible circuit board 2 is used as the first flexible circuit board 1051 connecting the main board 103 and the sub board 104, an air gap region (air gap) needs to be provided, and each layer of adhesive and EMI electromagnetic shielding film at the bending portion of the flexible circuit board 2 needs to be removed to disperse stress at the bending portion of the flexible circuit board 2, thereby improving bending performance of the flexible circuit board 2.

As shown in fig. 32, in the first wiring layer 203, a first ground line 203a and a first signal line 203b insulated from each other may be provided, the first signal line 203b being for forming an electrical connection with an external electric appliance to realize data transmission. The width D1 of the first ground line 203a, the width D2 of the first signal line 203b, and the distance D3 between the first ground line 203a and the first signal line 203b should satisfy that D1> d2+d3, so as to reduce the resistance of the first ground line 203a, improve the current carrying capacity of the first ground line 203a, reduce the interference of the first signal line 203b, and thus make the flexible circuit board 2 suitable for use in the circuit board assembly 10 with high current, high speed signals and high power. Similarly, as shown in fig. 33, in the second wiring layer 205, a second ground line 205a and a second signal line 205b may be provided, the second signal line 205b being for forming an electrical connection with an external electric appliance to realize data transmission. The width D4 of the second ground line 205a, the width D5 of the second signal line 205b, and the distance D6 between the second ground line 205a and the second signal line 205b should satisfy that D4> d5+d6.

Fig. 34 is a schematic cross-sectional structure of a flexible circuit board 2 according to another embodiment of the present application, and as shown in fig. 34, when the flexible circuit board 2 according to the embodiment of the present application has a three-layer wiring structure, the flexible circuit board 2 is sequentially 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 along a thickness direction Z of the flexible circuit board 2. The materials and parameters of the first electromagnetic shielding layer 201, the first cover layer 202, the first routing layer 203, the second routing layer 205, the second cover layer 206, and the second electromagnetic shielding layer 207 may refer to the data in table 3, and the materials and parameters of the first substrate layer 204a and the second substrate layer 204b may refer to the materials and data of the substrate layer 204 in table 3, which is not limited in the embodiment of the present application. The fourth pad 22 penetrates the first wiring layer 203, the first substrate layer 204a, the third wiring layer 208, the second substrate layer 204b, and the second wiring 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 around 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 may be connected by a via or a blind via.

When the flexible circuit board 2 is used as the first flexible circuit board 1051 connecting the main board 103 and the sub board 104, an air gap region (air gap) needs to be provided, and each layer of adhesive and EMI electromagnetic shielding film at the bending portion of the flexible circuit board 2 needs to be removed to disperse stress at the bending portion of the flexible circuit board 2, thereby improving bending performance of the flexible circuit board 2.

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A circuit board assembly, comprising:

a printed circuit board provided with a first bonding pad;

and the flexible circuit board is welded and fixed with the printed circuit board, a second bonding pad is arranged on at least one side surface of the flexible circuit board along the thickness direction of the flexible circuit board, and the second bonding pad is connected with the first bonding pad through metal lead bonding.

2. The circuit board assembly of claim 1, wherein the printed circuit board is provided with a first receiving slot and the flexible circuit board is solder-secured to a bottom wall of the first receiving slot.

3. The circuit board assembly of claim 2, wherein the first solder pad is disposed at a bottom wall of the first receiving slot.

4. The circuit board assembly according to claim 3, wherein the bottom wall of the first receiving groove is provided with a second receiving groove;

The circuit board assembly further comprises a chip, at least part of the chip is positioned in the second accommodating groove, and the flexible circuit board is welded and fixed with the chip along the thickness direction of the flexible circuit board, wherein the surface of one side of the flexible circuit board, which faces the second accommodating groove;

And the second bonding pad is arranged on one side surface of the flexible circuit board, which is far away from the second accommodating groove, along the thickness direction of the flexible circuit board.

5. The circuit board assembly of claim 3, further comprising a package structure filled within the first receiving slot.

6. The circuit board assembly according to claim 2, wherein the first pad is provided on a side surface of the printed circuit board having the first receiving groove in a thickness direction of the printed circuit board.

7. The circuit board assembly of claim 6, further comprising a package structure secured to a side surface of the printed circuit board having the first receiving slot;

The first bonding pad is located in the packaging structure.

8. The circuit board assembly according to claim 1, further comprising a chip, wherein a side surface of the flexible circuit board facing the printed circuit board is soldered to the chip in a thickness direction of the flexible circuit board;

And the second bonding pad is arranged on one side surface of the flexible circuit board far away from the printed circuit board along the thickness direction of the flexible circuit board.

9. The circuit board assembly according to claim 4 or 8, further comprising a reinforcing frame fixed to a side surface of the flexible circuit board remote from the chip in a thickness direction of the flexible circuit board;

the reinforcement frame is provided with a first accommodating space, and the second bonding pad is positioned in the first accommodating space.

10. The circuit board assembly of claim 8, wherein the printed circuit board is provided with a third receiving slot, at least a portion of the chip being received in the third receiving slot;

The flexible circuit board is welded and fixed on the surface of the printed circuit board on the side with the third accommodating groove along the thickness direction of the printed circuit board, and the first bonding pad is arranged on the surface of the printed circuit board on the side with the third accommodating groove.

11. The circuit board assembly of claim 10, further comprising an electronic component, the electronic component being soldered to the second pad.

12. The circuit board assembly of claim 11, further comprising a package structure secured to a side surface of the printed circuit board having the third receiving slot;

the first bonding pad, the second bonding pad and the electronic element are located in the packaging structure.

13. The circuit board assembly according to claim 8, wherein the printed circuit board comprises a main body and a connection board, one side surface of the connection board is welded to the main body, and the other side of the connection board is welded to the connection board in a thickness direction of the connection board;

The first bonding pad is arranged on one side surface of the connecting plate away from the main body along the thickness direction of the connecting plate.

14. The circuit board assembly according to claim 13, further comprising a reinforcing member fixedly connected to a surface of the flexible circuit board on which the chip is provided in a thickness direction of the flexible circuit board;

The reinforcement piece is circumferentially arranged along the chip.

15. The circuit board assembly of claim 13, further comprising a package structure comprising a first sub-package structure and a second sub-package structure;

the first sub-packaging structure is fixed on the surface of one side of the connecting plate, which is provided with the first bonding pad, and the first bonding pad and the second bonding pad are positioned in the first sub-packaging structure;

And a second accommodating space is formed among the chip, the connecting plate and the main body, and the second sub-packaging structure is filled in the second accommodating space.

16. The circuit board assembly of claim 1, wherein the flexible circuit board comprises a plurality of the second pads, the plurality of second pads being distributed in an array;

And the distance between the center line of any one second bonding pad and the center line of the other adjacent second bonding pad along the width direction of the second bonding pads is 0.1mm-3.0mm.

17. The circuit board assembly of claim 1, wherein the printed circuit board is further provided with a third pad and the flexible circuit board is further provided with a fourth pad;

The fourth bonding pad is welded and fixed with the third bonding pad through a welding spot, the fourth bonding pad comprises a through hole penetrating through the flexible circuit board along the thickness direction of the flexible circuit board, and at least part of the welding spot is positioned in the through hole.

18. The circuit board assembly of claim 17, wherein the flexible circuit board comprises a plurality of the second pads, the plurality of second pads being distributed in an array;

The array is provided with a first side and a second side which are distributed oppositely along the width direction of the flexible circuit board, and a third side and a fourth side which are distributed oppositely along the length direction of the flexible circuit board, wherein at least two of the first side, the second side, the third side and the fourth side are provided with the fourth bonding pads.

19. An electronic device comprising the circuit board assembly of any one of claims 1-18.

20. The electronic device of claim 19, wherein the printed circuit board is a motherboard, the electronic device further comprising a camera module, the flexible circuit board being connected to the camera module at an end remote from the motherboard;

Or the electronic equipment further comprises a sound cavity module, and one end, far away from the main board, of the flexible circuit board is connected with the sound cavity module.

21. The electronic device of claim 19, wherein the printed circuit board is a motherboard, the electronic device further comprising a first housing, a second housing, and a sub-board, the motherboard and the sub-board being disposed within the first housing and the second housing, respectively;

The first shell is connected with the second shell through a rotating shaft, one end of the flexible circuit board is connected with the main board, and the other end of the flexible circuit board is connected with the auxiliary board through the first shell, the rotating shaft and the second shell.

22. The electronic device of claim 19, wherein the printed circuit board is a control board of a battery protection board;

The electronic equipment further comprises a main board, and one end, far away from the control board, of the flexible circuit board is connected with the main board.