Circuit board, electronic component and electronic equipment

Abstract

The invention provides a circuit board, an electronic assembly and electronic equipment. The circuit board comprises a transmission area and a connection area. The connecting area comprises a bending area and a pin area, and the pin area, the bending area and the transmission area are divided at the angle of a plane. The connection area comprises a plurality of pins, and the plurality of pins are connected with the signal lines. Specifically, the pins are arranged in the pin area and used for being connected with other electronic assemblies. The thickness of the bending area is smaller than that of the transmission area, so that the bending area has good flexibility, the insertion loss and impedance of the whole circuit board are balanced, and the circuit board can give consideration to multiple performance indexes such as insertion loss, impedance and flexibility.

Description

Technical Field

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

[0002] Flexible circuit board (FPC) has the advantages of high density and lightness. FPC can be welded to printed circuit board (PCB) so that FPC is connected to PCB to realize signal transmission on the board.

[0003] With the development of technology, the transmission rate of signals is getting higher and higher, and the density of the system is also increasing. In order to meet the high-speed and high-density requirements of the system, it is necessary to reduce the loss in the signal transmission path as much as possible. As an important carrier on the signal transmission path, how to reduce the insertion loss of flexible circuit boards is an important development direction for the development of flexible circuit boards. In addition, the flexibility of flexible circuit boards in the bending area is also an important performance indicator, which has an important impact on the connection reliability of flexible circuit boards in the bending area. Summary of the invention

[0004] The present application provides a circuit board, an electronic component and an electronic device. The circuit board in the present application can take into account multiple performance indicators such as insertion loss, impedance and flexibility.

[0005] In the first aspect, the present application provides a circuit board. The circuit board includes a transmission area and a connection area. The connection area includes a bending area and a pin area, and the division of the pin area, the bending area and the transmission area is divided from the perspective of the plane. From the perspective of the layer structure, the circuit board includes a signal layer and a dielectric layer, and the signal layer is located between two dielectric layers, so that the dielectric layer can protect the signal layer and can achieve insulation between different signal layers. The signal layer includes a plurality of signal lines, and the signal lines extend from the transmission area to the connection area. Each connection area includes a plurality of pins, which are connected to the signal lines, and the signal lines connect the pins between the two connection areas, thereby realizing signal transmission between the two connection areas. The pins are specifically arranged in the pin area for connecting with other electronic components; or the pin area is used to set the pins. The thickness of the bending area is less than the thickness of the transmission area, so that the bending area has good flexibility, and the insertion loss and impedance of the entire circuit board are balanced, so that the circuit board in the present application can take into account multiple performance indicators such as insertion loss, impedance and flexibility.

[0006] In one technical solution, the cross-sectional area of ​​the signal line in the connection area is smaller than the cross-sectional area of ​​the same signal line in the transmission area. Then the signal line is thinner in the connection area, and thicker in the transmission area. If the signal line is thinner in the connection area, it will occupy less space, so that the density of the pins of the circuit board in the pinmap is set denser, which is conducive to reducing the area of ​​the connection area, reducing the volume of the electronic equipment, and improving the integration of the electronic equipment. The signal line is thinner in the connection area, with greater insertion loss and greater impedance; the signal line is thicker in the transmission area, with less insertion loss and less impedance, so that the insertion loss and impedance of the entire signal line can be optimized, so that the overall insertion loss of the signal line is less and the impedance is lower.

[0007] In a technical solution, the spacing between adjacent signal lines located on the same layer in the transmission area is greater than the spacing in the connection area. The signal lines are denser in the connection area, so that the density of the pins of the circuit board in the pinmap is set larger, which is conducive to reducing the area of ​​the second connection area, reducing the volume of the electronic device, and improving the integration of the electronic device. The spacing between the signal lines is small, especially the spacing between the same pair of differential signal lines is small, so that the signal lines are tightly coupled, which will produce a large insertion loss. The spacing between adjacent signal lines in the transmission area is larger and sparser, which can reduce the insertion loss and make the overall insertion loss of the signal line lower. This embodiment further optimizes the relationship between the area and insertion loss of the connection area of ​​the circuit board, so as to obtain a lower insertion loss when the circuit board has a smaller area of ​​the connection area, and improve the rate at which the circuit board transmits signals to meet the high-density and high-speed requirements of electronic equipment.

[0008] The length of the bending zone along the direction from the pin zone to the transmission zone is greater than or equal to a preset value. The bending zone is thin and has a certain length, so that the circuit board can be conveniently bent in the bending zone to meet the bending requirements. The preset value is specifically selected based on the bending requirements of the circuit board in the direction close to the connection zone and the flexibility of the circuit board in the connection zone.

[0009] In a specific technical solution, the above preset value includes 60mm, which can meet the bending requirements of more electronic components.

[0010] In a possible technical solution, the pin area and the bending area of ​​the circuit board are all flexible circuit boards. Specifically, the pin area, the bending area and the transmission area are all flexible circuit boards, and the preparation process is relatively simple.

[0011] In another possible technical solution, the pin area of ​​the circuit board includes a rigid circuit board, while the bending area and the transmission area are flexible circuit boards, so that the entire circuit board is a combination of hard and soft structure. In this technical solution, the bending area has sufficient flexibility for bending, and it is conducive to setting relatively dense pins in the pin area, so that the circuit board can take into account both high density and flexible bending characteristics.

[0012] In a possible technical solution, the pin area of ​​the circuit board includes a rigid circuit board, and the rigid circuit board connects two flexible circuit boards. Among them, one flexible circuit board includes a first bending area and a first transmission area connected to each other, and the first bending area is connected to the rigid circuit board; the other flexible circuit board includes a second bending area and a second transmission area connected to each other, and the second bending area is also connected to the rigid circuit board. The first transmission area and the second transmission area are stacked and have a gap. The circuit board in this solution can have more routing space, so that the number of signals transmitted by the circuit board can be increased. In addition, the two independent layers of flexible circuit boards make the circuit board more flexible.

[0013] From the perspective of layer structure, the circuit board of the present application also includes a first ground layer and a second ground layer, and the signal layer is located between the first ground layer and the second ground layer. The first ground layer and the second ground layer serve as the ground layer of the circuit board or as a shielding layer to increase the rate at which the signal layer transmits signals.

[0014] In another possible technical solution, the signal layer of the circuit board of the present application includes a first signal layer and a second signal layer, and the first signal layer and the second signal layer are located on both sides of a dielectric layer. The number of signal layers of the circuit board in this embodiment is large, and the area of ​​the signal layer used to prepare the signal line is large, so the number of signal lines can be increased. This solution can improve the integration of the circuit board, so that the circuit board can transmit a large number of signals.

[0015] In order to improve the rate at which the circuit board transmits signals, the signal layer includes a third signal layer and a fourth signal layer, and a third ground layer is further provided between the third signal layer and the fourth signal layer. The third ground layer can be used as a shielding layer between the third signal layer and the fourth signal layer to reduce crosstalk between the third signal layer and the fourth signal layer, which is beneficial to improving the rate at which the circuit board transmits signals.

[0016] The circuit board includes a first side and a second side that are opposite to each other in the thickness direction. There are multiple options for achieving a solution in which the thickness of the bending area is smaller than the thickness of the transmission area. In one option, on the first side of the circuit board, the surface of the bending area and the surface of the transmission area are located in different planes, and on the second side, the surface of the bending area and the surface of the transmission area are located in the same plane. The thickness of the connection area is thinned only on one side of the bending area, simplifying the manufacturing process of the circuit board.

[0017] In one option, on the first side of the circuit board, the surface of the bending area and the surface of the transmission area are located in different planes; on the second side of the circuit board, the surface of the bending area and the surface of the transmission area are located in different planes. The circuit board can be more symmetrical in the thickness direction, and the symmetry of the transmitted signal is also better, which is conducive to improving the quality of the circuit board's transmitted signal.

[0018] The material of the dielectric layer can have a variety of options, for example, the material of the dielectric layer includes at least one of modified polyimide, liquid crystal polymer, fluorinated ethylene propylene copolymer and polytetrafluoroethylene. The above materials have good flexibility and produce low signal loss, which can further reduce the insertion loss of the circuit board transmission signal.

[0019] In the second aspect, the present application also provides a method for preparing a circuit board. The circuit board prepared by the method for preparing the circuit board can be the circuit board provided in the first aspect above. The circuit board includes a transmission area and a connection area, and the transmission area and the connection area are connected. The above preparation method includes: forming a signal circuit pattern on the first metal layer on the surface of the first flexible metal-clad plate, and the surface of the first flexible metal-clad plate away from the first metal layer has a second metal layer; pressing the third metal layer, the first adhesive layer and the first flexible metal-clad plate stacked in sequence, and the third metal layer is located on the side of the first metal layer away from the second metal layer; preparing a conductive hole, and the conductive hole connects at least two layers of the first metal layer, the second metal layer and the third metal layer; pressing the second flexible metal-clad plate, the second adhesive layer and the third metal layer stacked in sequence; the second flexible metal-clad plate includes a fourth metal layer, and the fourth metal layer is located on the surface away from the third metal layer, and the second flexible metal-clad plate and the second adhesive layer cover part of the transmission area. The thickness of the transmission area of ​​the circuit board prepared by the preparation method is greater than the thickness of the connection area, so that the connection area has good flexibility, and can take into account multiple performance indicators such as insertion loss, impedance and flexibility of the circuit board.

[0020] Furthermore, the above lamination sequentially stacks the second flexible metal-clad plate, the second adhesive layer and the third metal layer; the second flexible metal-clad plate includes a fourth metal layer, the fourth metal layer is located on the surface away from the third metal layer, and the second flexible metal-clad plate and the second adhesive layer cover the part of the transmission area, before including: setting a blocking member on the surface of the first metal layer; after including: removing the blocking member. This is conducive to the second flexible metal-clad plate and the second adhesive layer covering the transmission area more accurately and reliably.

[0021] In a specific technical solution, the signal line pattern includes a signal line, the cross-sectional area of ​​the signal line in the connection area is smaller than the cross-sectional area of ​​the same signal line in the transmission area, and the spacing between adjacent signal lines in the connection area is smaller than the spacing in the transmission area. This reduces the insertion loss of the circuit board and optimizes the impedance of the circuit board, so as to improve the density and rate of the signal transmitted by the circuit board.

[0022] In a third aspect, the present application also provides a method for preparing a circuit board. The circuit board prepared by the method for preparing a circuit board may be the circuit board provided in the first aspect above. The circuit board includes a transmission area and a connection area, and the transmission area and the connection area are connected. The above preparation method includes: forming a signal circuit pattern on the first metal layer on the surface of the first flexible metal-clad plate, and the surface of the first flexible metal-clad plate facing away from the first metal layer has a second metal layer; pressing the third metal layer, the first adhesive layer and the first flexible metal-clad plate stacked in sequence, and the third metal layer is located on the side of the first metal layer facing away from the second metal layer; preparing conductive holes, and the conductive holes connect at least two layers of the first metal layer, the second metal layer and the third metal layer; pressing the fourth metal layer, the second adhesive layer and the second metal layer stacked in sequence, and the fourth metal layer covers part of the transmission area.

[0023] Furthermore, the fourth metal layer, the second adhesive layer and the second metal layer are laminated in sequence, and the fourth metal layer covers the part of the transmission area, and before that, a blocking member is provided on the surface of the first metal layer; and after that, the blocking member is removed. This is conducive to the second flexible metal-clad plate and the second adhesive layer covering the transmission area more accurately and reliably.

[0024] In a specific technical solution, the signal line pattern includes a signal line, the cross-sectional area of ​​the signal line in the connection area is smaller than the cross-sectional area of ​​the same signal line in the transmission area, and the spacing between adjacent signal lines in the connection area is smaller than the spacing in the transmission area. This reduces the insertion loss of the circuit board and optimizes the impedance of the circuit board, so as to improve the density and rate of the signal transmitted by the circuit board.

[0025] In a fourth aspect, the present application further provides a method for preparing a circuit board. The circuit board prepared by the method for preparing a circuit board may be the circuit board provided in the first aspect. The circuit board includes a transmission area and a connection area, and the transmission area and the connection area are connected. The preparation method comprises: forming signal circuit patterns on the first metal layer and the second metal layer on both side surfaces of the first flexible metal clad plate respectively, and the first metal layer and the second metal layer are respectively located on both side surfaces of the first flexible metal clad plate; pressing the third metal layer, the first adhesive layer, the first flexible metal clad plate, the second adhesive layer and the fourth metal layer stacked in sequence; preparing conductive holes to connect at least two layers of the first metal layer, the second metal layer, the third metal layer and the fourth metal layer; pressing the second flexible metal clad plate, the third adhesive layer, the third metal layer, the first adhesive layer, the first flexible metal clad plate, the second adhesive layer, the fourth metal layer, the fourth adhesive layer and the third flexible metal clad plate stacked in sequence; the second flexible metal clad plate and the third flexible metal clad plate respectively cover parts of the transmission area; the second flexible metal clad plate includes a fifth metal layer, and the fifth metal layer is located on the side away from the first flexible metal clad plate; the third flexible metal clad plate includes a sixth metal layer, and the sixth metal layer is located on the side away from the first flexible metal clad plate.

[0026] Furthermore, the above-mentioned lamination sequentially stacks the second flexible metal-clad plate, the third adhesive layer, the third metal layer, the first adhesive layer, the first flexible metal-clad plate, the second adhesive layer, the fourth metal layer, the fourth adhesive layer and the third flexible metal-clad plate; the second flexible metal-clad plate and the third flexible metal-clad plate respectively cover the part of the transmission area, before including: setting a blocking member on the surface of the first metal layer; after including: removing the above-mentioned blocking member. This is conducive to the above-mentioned second flexible metal-clad plate and the second adhesive layer covering the transmission area more accurately and reliably

[0027] In a specific technical solution, the signal line pattern includes a signal line, the cross-sectional area of ​​the signal line in the connection area is smaller than the cross-sectional area of ​​the same signal line in the transmission area, and the spacing between adjacent signal lines in the connection area is smaller than the spacing in the transmission area. This reduces the insertion loss of the circuit board and optimizes the impedance of the circuit board, so as to improve the density and rate of the signal transmitted by the circuit board.

[0028] In a fifth aspect, the present application also provides a method for preparing a circuit board. The circuit board prepared by the method for preparing a circuit board may be the circuit board provided in the first aspect above. The circuit board includes a transmission area and a connection area, and the transmission area and the connection area are connected. The above preparation method includes: forming a signal circuit pattern on the first metal layer of the first flexible metal-clad plate and the second metal layer of the second flexible metal-clad plate, respectively, forming a circuit pattern on the third metal layer of the first flexible metal-clad plate, the first metal layer and the third metal layer are respectively located on the two side surfaces of the first flexible metal-clad plate, and the surface of the second flexible metal-clad plate away from the second metal layer has a fourth metal layer; pressing the fifth metal layer, the first adhesive layer, the first flexible metal-clad plate, the second adhesive layer and the second flexible metal-clad plate stacked in sequence, the first metal layer is adjacent to the first adhesive layer, and the second metal layer is adjacent to the second adhesive layer; preparing conductive holes to connect at least two layers of the first metal layer, the second metal layer, the third metal layer, the fourth metal layer and the fifth metal layer; pressing the sixth metal layer, the third adhesive layer and the second flexible metal-clad plate stacked in sequence, and the sixth metal layer covers part of the transmission area.

[0029] Furthermore, the sixth metal layer, the third adhesive layer and the second flexible metal-clad plate are laminated in sequence, and the sixth metal layer covers the part of the transmission area, and before that, a blocking member is provided on the surface of the first metal layer; and after that, the blocking member is removed. This is conducive to the second flexible metal-clad plate and the second adhesive layer covering the transmission area more accurately and reliably.

[0030] In a specific technical solution, the signal line pattern includes a signal line, the cross-sectional area of ​​the signal line in the connection area is smaller than the cross-sectional area of ​​the same signal line in the transmission area, and the spacing between adjacent signal lines in the connection area is smaller than the spacing in the transmission area. This reduces the insertion loss of the circuit board and optimizes the impedance of the circuit board, so as to improve the density and rate of the signal transmitted by the circuit board.

[0031] In a sixth aspect, the present application also provides an electronic component. The electronic component includes a printed circuit board and the circuit board provided in the first aspect above, and at least one connection area of ​​the circuit board is electrically connected to the printed circuit board. The area of ​​the circuit board close to the printed circuit board has good flexibility, and the connection between the circuit board and the printed circuit board is more reliable. The circuit board can take into account multiple performance indicators such as insertion loss, impedance and flexibility, and improve the signal transmission rate of the electronic component.

[0032] In a seventh aspect, the present application further provides an electronic device. The electronic component comprises a housing and the electronic component provided in the sixth aspect, and the electronic component is arranged in the housing. The electronic device has a fast signal transmission rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the structure of an electronic device in an embodiment of the present application;

[0034] Figure 2 A schematic diagram of the structure of an electronic component in an embodiment of the present application;

[0035] Figure 3 Another structural schematic diagram of an electronic component in an embodiment of the present application;

[0036] Figure 4 Another structural schematic diagram of an electronic component in an embodiment of the present application;

[0037] Figure 5 Another structural schematic diagram of an electronic component in an embodiment of the present application;

[0038] Figure 6 Another structural schematic diagram of an electronic component in an embodiment of the present application;

[0039] Figure 7 Another structural schematic diagram of an electronic component in an embodiment of the present application;

[0040] Figure 8 Another structural schematic diagram of an electronic component in an embodiment of the present application;

[0041] Fig. 9 Another structural schematic diagram of an electronic component in an embodiment of the present application;

[0042] Fig.10 A schematic diagram of the structure of a circuit board in an embodiment of the present application;

[0043] Fig.11 A schematic diagram of a top view of the circuit board in an embodiment of the present application;

[0044] Fig.12 A schematic diagram of a top view of the circuit board in an embodiment of the present application;

[0045] Fig.13 A schematic diagram of the structure of a circuit board in an embodiment of the present application;

[0046] Fig.14 A schematic diagram of a top view of the circuit board in an embodiment of the present application;

[0047] Fig.15 A schematic diagram of a top view of the circuit board in an embodiment of the present application;

[0048] Fig.16 A schematic diagram of a top view of the circuit board in an embodiment of the present application;

[0049] Fig.17 A schematic diagram of the structure of a circuit board in an embodiment of the present application;

[0050] Fig.18 Another structural schematic diagram of a circuit board in an embodiment of the present application;

[0051] Fig.19 A schematic diagram of the structure of a circuit board in an embodiment of the present application;

[0052] Fig. 20 A schematic diagram of the structure of a circuit board in an embodiment of the present application;

[0053] Fig.21 A schematic diagram of a top view of the circuit board in an embodiment of the present application;

[0054] Fig. 22 A schematic diagram of the structure of a circuit board in an embodiment of the present application;

[0055] Fig.23 A schematic diagram of the structure of a circuit board in an embodiment of the present application;

[0056] Fig.24 A schematic diagram of the structure of a circuit board in an embodiment of the present application;

[0057] Fig.25 This is a schematic diagram of the structure of a circuit board in an embodiment of the present application.

[0058] Reference numerals:

[0059] 100-housing; 200-electronic components;

[0060] 1-Printed circuit board; 2-Circuit board;

[0061] 21-transmission area; 211-first transmission area;

[0062] 212-second transmission area; 22-connection area;

[0063] 221-first connection area; 222-second connection area;

[0064] 223-pin area; 224-bending area;

[0065] 2241-first bending zone; 2242-second bending zone;

[0066] 23-pin; 24-signal layer;

[0067] 241-signal line; 242-first signal layer;

[0068] 243-second signal layer; 244-third signal layer;

[0069] 245- fourth signal layer; 25- dielectric layer;

[0070] 26-first stratum; 27-second stratum;

[0071] 28-third stratum; 29-first side;

[0072] 210-second side; 3-connector;

[0073] 4-Packaging structure; L1-First metal layer;

[0074] L2-second metal layer; L3-third metal layer;

[0075] L4-the fourth metal layer; L5-the fifth metal layer;

[0076] L6-sixth metal layer; BS1-first bonding layer;

[0077] BS2-second adhesive layer; BS3-third adhesive layer;

[0078] BS4-fourth adhesive layer; FL1-first flexible metal-clad plate;

[0079] FL2-second flexible metal-clad plate; FL3-third flexible metal-clad plate;

[0080] 5-Blocking piece. DETAILED DESCRIPTION

[0081] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0082] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to be limiting of the present application. As used in the specification and appended claims of the present application, the singular expressions "a", "an", "said", "above", "the" and "this" are intended to also include expressions such as "one or more", unless there is a clear contrary indication in the context.

[0083] References to "one embodiment" or "a specific embodiment" described in this specification mean that one or more embodiments of the present application include a particular feature, structure or characteristic described in conjunction with the embodiment. The terms "include", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0084] In order to facilitate understanding of the electronic components and electronic devices provided in the embodiments of the present application, their application scenarios are first introduced below.

[0085] The electronic device in the embodiment of the present application can be an electronic device such as information and communication technology (ICT) equipment, a communication device (such as a router), a computing device (such as a server), a network device (such as a switch) or a storage device (such as a storage array), or an electronic device such as an optical module, a vehicle-mounted device or a terminal device. The present application does not limit the specific type of electronic device, as long as the electronic device includes an electronic component that uses a circuit board to transmit a signal, the technical solution provided in the present application can be adopted.

[0086] For ease of description, the embodiments of the present application are described by taking the electronic device as a server as an example. Figure 1 is a schematic diagram of the structure of an electronic device in an embodiment of the present application, such as Figure 1 As shown, the electronic device may include a housing 100 and an electronic component 200 disposed in the housing 100. Specifically, when the electronic device is a cabinet server, the housing 100 may be understood as a cabinet of the cabinet server, and the electronic component 200 may include a node. Figure 1 As shown, the electronic component 200 specifically includes a printed circuit board 1 and a circuit board 2. The printed circuit board 1 is welded to the circuit board 2 to achieve electrical connection between the printed circuit board 1 and the circuit board 2, and further, physical connection and signal connection between the printed circuit board 1 and the circuit board 2 can be achieved.

[0087] Specifically, there are many options for connecting the printed circuit board 1 and the circuit board 2, such as laser welding, hard connection, crimping, sintering, conductive adhesive bonding, hot bar welding, connector connection or surface mounted technology (SMT).

[0088] The circuit board 2 can be applied to different application scenarios, or the electronic component 200 can include different components. For example, Figure 2 is a schematic diagram of the structure of an electronic component in an embodiment of the present application, such as Figure 2 As shown, in a specific embodiment, the circuit board 2 in the electronic assembly 200 is used to implement a single-board jumper of the printed circuit board 1. Specifically, both ends of the circuit board 2 are soldered to the same printed circuit board 1 to achieve signal transmission of devices at two positions in the printed circuit board 1. Figure 3 is another structural schematic diagram of the electronic component in the embodiment of the present application, such as Figure 3 As shown, in another specific embodiment, the electronic component 200 may include two printed circuit boards 1, and the two printed circuit boards 1 are approximately located in the same plane. The two ends of the circuit board 2 are respectively welded to the two printed circuit boards 1, so that the circuit board 2 is connected between the two printed circuit boards 1, so that the signals between the two printed circuit boards 1 can be transmitted through the circuit board 2 to achieve interconnection between the boards. Figure 4 is another structural schematic diagram of the electronic component in the embodiment of the present application, such as Figure 4 As shown, in another specific embodiment, the electronic component 200 may also include two printed circuit boards 1. The two printed circuit boards 1 in this embodiment are located in different planes. The two ends of the circuit board 2 are respectively welded to the two printed circuit boards 1, so that the circuit board 2 is connected between the two printed circuit boards 1, so that the signals between the two printed circuit boards 1 can be transmitted through the circuit board 2 to achieve cross-board connection. Figure 5 is another structural schematic diagram of the electronic component in the embodiment of the present application, such as Figure 5 As shown, in another specific embodiment, one end of the circuit board 2 in the electronic component 200 is welded to the printed circuit board 1, and the other end is connected to the connector 3, so that the connector 3 and the printed circuit board 1 can be transmitted through the circuit board 2, and then the printed circuit board 1 can be connected to an external device through the connector 3, and the printed circuit board 1, the circuit board 2 and the connector 3 form an electronic module. Figure 6 is another structural schematic diagram of the electronic component in the embodiment of the present application, such as Figure 6As shown, in another specific embodiment, the circuit board 2 realizes the connection between the packaging structure 4 and the printed circuit board 1, so that signals can be transmitted between the packaging structure 4 and the printed circuit board 1. Specifically, one end of the circuit board 2 is connected to the packaging structure 4, and the other end is connected to the printed circuit board 1.

[0089] Figure 7 is another structural schematic diagram of the electronic component in the embodiment of the present application, such as Figure 7 As shown, in another specific embodiment, a circuit board 2 may be welded on the surface of the printed circuit board 1 . Figure 8 is another structural schematic diagram of the electronic component in the embodiment of the present application, such as Figure 8 As shown, in another specific embodiment, a plurality of stacked circuit boards 2 may be welded on the surface of the printed circuit board 1. In addition, a circuit board 2 may be connected to one side of the printed circuit board 1, such as Figure 7 and Figure 8 as shown. Alternatively, Fig. 9 is another structural schematic diagram of the electronic component in the embodiment of the present application, such as Fig. 9 As shown, in another specific embodiment, both sides of the printed circuit board 1 can be connected to the circuit board 2 respectively.

[0090] Fig.10 This is a schematic diagram of the structure of a circuit board in an embodiment of the present application. Fig.11 Schematic diagram of a top view of the circuit board in the embodiment of the present application. Fig.10 and Fig.11As shown, in one embodiment, the circuit board 2 includes a transmission area 21 and at least two connection areas 22, and the connection areas 22 are used to connect with other electronic devices, for example, at least one connection area 22 is used to electrically connect with the printed circuit board 1. Specifically, each connection area 22 includes a plurality of pins 23, and the plurality of pins 23 are arranged in the connection area 22 of the circuit board 2 to form a pinmap, and the pins 23 are welded with other electronic devices to achieve the connection between the circuit board 2 and other electronic devices, for example, the pins 23 of the connection area 22 are welded with the printed circuit board 1. The above specifically includes a bending area 224 and a pin area 223, and the pins 23 are specifically arranged in the pin area 223, and the bending area 224 is located between the pin area 223 and the transmission area 21. For the convenience of description, it is considered that the at least two connection areas 22 include a first connection area 221 and a second connection area 222, and the transmission area 21 is located between the bending area 224 and the second connection area 222. For the convenience of description, the present application only takes the first connection area as an example for description, and the bending area 224 and the pin area 223 in the embodiment of the present application refer to adjacent bending areas 224 and pin areas 223. It is worth noting that the transmission area 21 and the connection area 22 of the above-mentioned circuit board 2 are only for the convenience of describing the areas where the circuit board 2 is divided, and there may not be a clear boundary in the actual structure of the circuit board 2 to distinguish the transmission area 21 and the connection area 22. The main difference between the connection area 22 and the transmission area 21 is that the connection area 22 includes a plurality of pins 23 for connecting to other electronic devices, and the main function is to be used for connecting to other electronic devices.

[0091] Please continue to refer to Fig.10 and Fig.11 From the perspective of layer structure, the circuit board 2 includes a signal layer 24 and a dielectric layer 25, and a signal layer 24 is located between two adjacent dielectric layers 25. Specifically, the signal layer 24 includes a signal line 241 for transmitting signals; and the dielectric layer 25 is mainly an insulator, which is used to separate different layers of signal layers 24 and protect the signal layer 24. Specifically, the signal line 241 is connected to the pin 23 of the connection area 22, for example, one end of the signal line 241 is connected to the pin 23 of the bending area 224, and the other end of the signal line 241 is connected to the pin 23 of the second connection area 222.

[0092] In a specific embodiment, the signal layer 24 may be a copper layer, a silver layer or a gold layer to reduce the loss of the signal transmitted by the signal layer 24 and improve the signal transmission rate. The dielectric layer 25 may be a low-loss dielectric, for example, the material of the dielectric layer 25 includes at least one of modified polyimide (PI), liquid crystal polymer (LCP), fluorinated ethylene propylene (FEP) and polytetrafluoroethylene (PTFE). The above materials have good flexibility and generate low signal loss, which can further reduce the insertion loss of the signal transmitted by the circuit board 2.

[0093] In the embodiment provided by the present application, the thickness of the bending area 224 is less than the thickness of the transmission area 21. The thickness of the bending area 224 of the circuit board 2 is relatively thin, so that the impedance can be reduced. However, the thin thickness of the bending area 224 will also lead to a large insertion loss, while the thick thickness of the transmission area 21 can reduce the insertion loss, so that the insertion loss of the entire signal transmission path of the circuit board 2 is relatively low. Correspondingly, the thick thickness of the transmission area 21 of the circuit board 2 will also lead to an increase in impedance, but the impedance of the bending area 224 is relatively small, which can make the impedance of the entire signal transmission path of the circuit board 2 relatively small. In addition, the flexibility of the circuit board 2 is also strongly related to the thickness of the circuit board 2. During use, the flexibility of the circuit board 2 at the bend 22 is usually required to be high. In the present application, the thickness of the bending area 224 is relatively thin, so the flexibility is relatively high, making the circuit board 2 more flexible during use. Therefore, the circuit board 2 in the technical solution of the present application takes into account multiple performance indicators such as insertion loss, impedance and flexibility, especially for high-density and high-speed electronic devices, such as electronic devices with a rate of more than 112G, which has obvious advantages.

[0094] In an optional embodiment, the thickness of the bending zone 224 of all the connection zones 22 of the circuit board 2 can be smaller than the thickness of the transmission zone 21 , or the thickness of the bending zone 224 of some of the connection zones 22 can be smaller than the thickness of the transmission zone 21 .

[0095] Please continue to refer to Fig.11, the cross-sectional area of ​​the signal line 241 in the connection area 22 is smaller than the cross-sectional area of ​​the same signal line 241 in the transmission area 21, that is, the signal line 241 in the connection area 22 is thinner than the same signal line 241 in the transmission area 21. In one embodiment, the cross-sectional area of ​​the signal line 241 in the connection area 22 is smaller than the cross-sectional area of ​​the same signal line 241 in the transmission area 21. The thinner the signal line 241 is in the connection area 22, the less space it occupies, so that the density of the pins 23 of the pinmap of the flexible circuit board 2 is set larger, which is conducive to reducing the area of ​​the connection area 22, reducing the volume of the electronic device, and improving the integration of the electronic device. The signal line 241 is thinner in the connection area 22, the insertion loss is larger, and the impedance is also larger; the signal line 241 is thicker in the transmission area 21, the insertion loss is smaller, and the impedance is also smaller, so that the insertion loss and impedance of the entire signal line 241 can be optimized, so that the overall insertion loss of the signal line 241 is less and the impedance is lower.

[0096] In a specific embodiment, when the thickness of the circuit board 2 is the same for the signal line 241, the cross-sectional area is mainly affected by the line width, and it can also be understood that the line width of the signal line 241 in the bending area 224 is smaller than the line width of the same signal line 241 in the transmission area 21. The line width of the signal line 241 in the second connection area 222 is smaller than the line width of the same signal line 241 in the transmission area 21.

[0097] Please continue to refer to Fig.11 , the spacing between adjacent signal lines 241 located on the same layer in the transmission area 21 is greater than the spacing in the connection area 22, that is, the signal lines 241 are denser in the connection area 22 and sparser in the transmission area 21. In a specific embodiment, the spacing between adjacent signal lines 241 located on the same layer in the transmission area 21 is greater than the spacing in the connection area 22. When multiple signal lines 241 on the same layer are arranged in the connection area 22, the spacing between adjacent signal lines 241 is smaller, and the space occupied is smaller, so that the density of the pins 23 of the pinmap of the circuit board 2 is set larger, which is conducive to reducing the area of ​​the connection area 22, reducing the volume of the electronic device, and improving the integration of the electronic device. The spacing between the signal lines 241 is small, especially the spacing between the same pair of differential signal lines is small, so that the signal lines 241 are tightly coupled, which will produce a large insertion loss; while the spacing between adjacent signal lines 241 in the transmission area 21 is large, which can reduce the insertion loss, so that the overall insertion loss of the signal lines 241 is low. This embodiment further optimizes the relationship between the area of ​​the connection area 22 of the circuit board 2 and the insertion loss, so as to obtain a lower insertion loss when the circuit board 2 has a smaller area of ​​the connection area 22, thereby increasing the signal transmission rate of the circuit board 2 to meet the high-density and high-speed requirements of electronic equipment. In one embodiment, the density of adjacent signal lines 241 located on the same layer in the transmission area 21 is less than the density in the bending area 224.

[0098] In the embodiment provided by the present application, the cross-sectional area of ​​the signal line 241 in the connection area 22 is smaller than the cross-sectional area of ​​the same signal line 241 in the transmission area 21, and the spacing between adjacent signal lines 241 in the same layer in the transmission area 21 is greater than the spacing in the connection area 22. The signal line 241 in the connection area 22 is arranged thinner and denser, which is convenient for arranging more dense pins 23 in the connection area 22, reducing the area of ​​the connection area 22, and thus reducing the area of ​​the circuit board 2. In this embodiment, the signal line 241 in the connection area 22 is a thin line width tightly coupled, resulting in a higher impedance of the circuit board 2 in the connection area 22; and the thickness of the connection area 22 of the circuit board 2 is thin, so that the impedance can be reduced. However, the thin thickness of the connection area 22 will also lead to a large insertion loss. The thickness of the transmission area 21 of the circuit board 2 is thicker, which can reduce the insertion loss, so that the insertion loss of the entire signal transmission path of the circuit board 2 is lower. Correspondingly, the thicker thickness of the transmission of the circuit board 2 will also lead to an increase in impedance, but the impedance of the bending area 224 is smaller, which can make the impedance of the entire signal transmission path of the circuit board 2 smaller. In addition, the transmission area 21 has a larger area for routing relative to the connection area 22, so the signal line 241 is set thicker and has a larger spacing in the transmission area 21, and the thick line is loosely coupled in the transmission area 21, which can reduce the impedance of the circuit board 2 in the connection area 22. In addition, the thickness of the connection area 22 in the present application is thinner, so the flexibility is higher, making the circuit board 2 more flexible during use. Therefore, the circuit board 2 in the technical solution of the present application takes into account multiple performance indicators such as insertion loss, impedance and flexibility, especially for high-density and high-speed electronic devices, such as electronic devices with a speed of more than 112G, it has obvious advantages.

[0099] The embodiment of the present application realizes the division of different areas on the same low-loss circuit board 2, and the connection area 22 at the end of the circuit board 2 can support the tight coupling design with thin traces. By setting a thinner bending area 224, the connection area 22 can maintain a lower target impedance requirement even when the signal line 241 is thinner and denser. The design of a loose coupling design with thick traces in the middle transmission area 21 can ensure lower loss performance in the longer transmission area 21. This solution solves both the impedance problem of the connection area 22 and the overall insertion loss problem.

[0100] Please continue to refer to Fig.11In one embodiment, the connection area 22 includes a pin area 223 and a bending area 224. The pins 23 of the circuit board are arranged in the pin area 223, and the pinmap is formed in the pin area 223. The bending area 224 is arranged between the pin area 223 and the transmission area 21, or in other words, for the side of the circuit board facing a connection area 22, the transmission area 21, the bending area 224 and the pin area 223 are arranged in sequence. The length of the bending area 224 along the direction from the pin area 223 to the transmission area 21 is greater than or equal to a preset value. The length of the bending area 224 along the extension direction of the circuit board 2 is greater than or equal to a preset value. Since the thickness of the connection area 22 is relatively thin, it has good flexibility, which is convenient for adjusting the shape of the circuit board 2 according to the position of the actual product. The pins 23 are fixed to other devices, and the area outside the pins 23 can be bent, that is, the bending area 224 can be bent. The length of the bending zone 224 along the direction from the pin zone 223 to the transmission zone 21 is greater than or equal to the preset value, so that the circuit board 2 can be bent in the bending zone 224 to meet the bending requirement. The preset value is selected specifically according to the bending requirement of the circuit board 2 in the direction close to the connection zone 22 and the flexibility of the circuit board 2 in the bending zone 224. For example, the stronger the bending requirement, the larger the bending angle, or the longer the bending distance, the larger the preset value is set; conversely, the weaker the bending requirement, the smaller the preset value is set. For example, the worse the flexibility of the connection zone 22, the larger the preset value is set; conversely, the better the flexibility of the connection zone 22, the smaller the preset value is set.

[0101] In an optional embodiment, the above preset value can be 60 mm, and the length of the bending zone 224 along the extension direction of the circuit board 2 is greater than or equal to 60 mm, which can meet the bending requirements of most electronic components, so that the circuit board 2 can be applied to a variety of application scenarios.

[0102] In one embodiment of the present application, the bending area 224, the pin area 223 and the transmission area 21 of the circuit board are all flexible circuit boards. The flexibility of the circuit board 2 is relatively uniform in the connection area 22, and the flexibility of the connection area 22 is consistent, and both have good flexibility. Specifically, the thickness of the bending area 224 is the same as the thickness of the pin area 223.

[0103] Fig.12 This is a schematic diagram of a top view of the circuit board in an embodiment of the present application. Fig.13 Schematic diagram of a circuit board in an embodiment of the present application. Fig.12 and Fig.13As shown, in one embodiment, the rigidity of the pin area 223 is greater than the rigidity of the bending area 224, and the pin area 223 includes a rigid circuit board. The circuit board 2 is a soft-rigid combination circuit board, most of which is flexible, and the pin areas 223 at both ends have a certain rigidity. This soft-rigid combination circuit board is also applicable to the technical solution provided in the present application. Providing a rigid circuit board in the pin area 223 is conducive to preparing relatively dense pins in the pin area 223, thereby increasing the density of the circuit board transmission signal. In a possible embodiment, the pin area 223 includes a rigid circuit board layer, and the rigid circuit board layer is sandwiched on both sides of the flexible circuit board. When preparing the above-mentioned circuit board, the flexible pin area 223, the bending area 224 and the transmission area 21 are first prepared, and then the rigid circuit board layers on both sides are prepared.

[0104] Fig.14 A schematic diagram of the structure of a circuit board in an embodiment of the present application is shown in FIG. Fig.14 As shown, the bending area 224 includes a first bending area 2241 and a second bending area 2242, and the transmission area 21 includes a first transmission area 211 and a second transmission area 212. The first bending area 2241 is connected to the first transmission area 211. Specifically, the first bending area 2241 and the first transmission area 211 can be an integral structure, forming a flexible circuit board; the second bending area 2242 is connected to the second transmission area 212. Specifically, the second bending area 2242 and the second transmission area 212 are an integral structure, forming a flexible circuit board. The first transmission area 211 and the second transmission area 212 are stacked and have a gap, so the two flexible circuit boards are stacked and have a gap. The pin area 223 of the circuit board includes a rigid circuit board, and the pin area 223 is connected to the first bending area 2241 and the second bending area 2242 respectively, that is, a rigid circuit board connects two layers of flexible circuit boards. The circuit board in this solution can have more routing space, so that the number of signals transmitted by the circuit board can be increased. In addition, the two independent layers of flexible circuit boards make the circuit board more flexible.

[0105] Please continue to refer to Fig.10 In one embodiment, the circuit board 2 further includes a first ground layer 26 and a second ground layer 27, and the signal layer 24 is located between the first ground layer 26 and the second ground layer 27. A dielectric layer 25 is provided between the first ground layer 26 and the signal layer 24, and a dielectric layer 25 is also provided between the second ground layer 27 and the signal layer 24. The first ground layer 26 and the second ground layer 27 serve as a grounding layer of the circuit board 2 or as a shielding layer.

[0106] The specific form of the pinmap of the pin area 223 of the circuit board 2 of the present application has many options. For example, Fig.11 As shown, in one embodiment, the pins 23 of the pinmap in the connection area 22 of the circuit board 2 are arranged in a matrix (box). Fig.15 Schematic diagram of a top view of the circuit board in the embodiment of the present application. Fig.15 As shown, in one embodiment, the pins 23 of the pinmap in the pin area 223 of the circuit board 2 are arranged in a staggered manner. Fig.16 Schematic diagram of a top view of the circuit board in the embodiment of the present application. Fig.16 As shown, in one embodiment, the pins 23 of the pinmap of the pin area 223 of the circuit board 2 are irregularly arranged. In this embodiment, the pitch of the pins 23 in the pinmap of the pin area 223 is 0.4 mm to 1 mm, and the density of the pins 23 is relatively high. Specifically, the pin pitch refers to the distance between the centers of two adjacent pins 23.

[0107] The specific form of the circuit board 2 in the embodiment of the present application has multiple options. Fig.17 This is a schematic diagram of the structure of a circuit board in an embodiment of the present application. Fig.18 FIG. 1 is another schematic diagram of the structure of the circuit board in the embodiment of the present application. In a possible embodiment, as Fig.18 As shown, the circuit board 2 may be a one-to-one type circuit board 2, that is, the circuit board 2 is used to realize signal transmission between two points. In this embodiment, the circuit board 2 may only include two connection areas 22, a first connection area 221 and a second connection area 222, and the first connection area 221 and the second connection area 222 are respectively located at two ends of the circuit board 2. Fig.18 As shown, in a possible embodiment, the circuit board 2 can be a one-to-many type circuit board 2, that is, the circuit board 2 is used to realize signal transmission between one point and multiple points. In this embodiment, the circuit board 2 includes multiple connection areas 22, one of which is located at one end of the circuit board 2, and at least two of which are located at the other end of the circuit board 2.

[0108] Fig.19 A schematic diagram of the structure of a circuit board in an embodiment of the present application is shown in FIG. Fig.19 As shown, in one embodiment, the signal layer 24 of the circuit board 2 includes a first signal layer 242 and a second signal layer 243, and the first signal layer 242 and the second signal layer 243 are located on both sides of a dielectric layer 25. In this embodiment, the number of signal layers 24 of the circuit board 2 is large, and the area of ​​the signal layer 24 used to prepare the signal line 241 is large, so the number of signal lines 241 can be increased. This solution can improve the integration of the circuit board 2, so that the circuit board 2 can transmit a large number of signals.

[0109] Fig. 20 A schematic diagram of the structure of a circuit board in an embodiment of the present application is shown in FIG. Fig. 20As shown, in one embodiment, the signal layer 24 of the circuit board 2 includes a third signal layer 244 and a fourth signal layer 245, and a third ground layer 28 is further provided between the third signal layer 244 and the fourth signal layer 245. Specifically, a dielectric layer 25 is provided between the third signal layer 244 and the third ground layer 28, and a dielectric layer 25 is also provided between the fourth signal layer 245 and the third ground layer 28. The third ground layer 28 can be used as a reference ground layer for the third signal layer 244 and / or the fourth signal layer 245. More importantly, the third ground layer 28 can be used as a shielding layer between the third signal layer 244 and the fourth signal layer 245 to reduce the crosstalk between the third signal layer 244 and the fourth signal layer 245, which is beneficial to improving the signal transmission rate of the circuit board 2.

[0110] Please continue to refer to Fig.19 and Fig. 20 There are many options for achieving a solution in which the thickness of the connection area 22 is smaller than the thickness of the transmission area 21, for example, Fig.19 As shown, the thickness of the connection area 22 can be reduced on both sides of the circuit board 2, so that the surface of the connection area 22 on one side of the circuit board 2 and the surface of the transmission area 21 are located in different planes, and the surface of the connection area 22 on the other side and the surface of the transmission area 21 are also located in different planes; or Fig. 20 As shown, the thickness of the connection area 22 can also be reduced on one side of the circuit board 2, so that the surface of the connection area 22 and the surface of the transmission area 21 on one side of the circuit board 2 are located in different planes, and the surface of the connection area 22 and the surface of the transmission area 21 on the other side are also located in the same plane.

[0111] like Fig.19 and Fig. 20 As shown, in the specific embodiment, for the convenience of description, it is considered that the circuit board 2 includes a first side 29 and a second side 210 that are opposite to each other in the thickness direction. Fig.19 As shown, in an optional implementation, on the first side 29 of the circuit board 2, the surface of the connection area 22 and the surface of the transmission area 21 are located in different planes; on the second side 210 of the circuit board 2, the surface of the connection area 22 and the surface of the transmission area 21 are located in different planes. Specifically, the distance between the surface of the connection area 22 on the first side 29 and the surface of the transmission area 21 on the second side 210 is smaller than the distance between the surface of the transmission area 21 on the first side 29 and the surface of the transmission area 21 on the second side 210; the distance between the surface of the connection area 22 on the second side 210 and the surface of the transmission area 21 on the first side 29 is smaller than the distance between the surface of the transmission area 21 on the second side 210 and the surface of the transmission area 21 on the first side 29. Specifically, the two side surfaces of the circuit board 2 can be made to be symmetrical structures along the thickness direction. In this embodiment, the circuit board 2 is symmetrical in the thickness direction, and the symmetry of the transmitted signal is also good, which is conducive to improving the quality of the signal transmitted by the circuit board 2.

[0112] like Fig. 20 As shown, in an optional implementation, the thickness of the connection area 22 is reduced on one side of the circuit board 2. Specifically, on the first side 29 of the circuit board 2, the surface of the connection area 22 and the surface of the transmission area 21 are located in different planes; on the second side 210 of the circuit board 2, the surface of the connection area 22 and the surface of the transmission area 21 are located in the same plane. Specifically, the distance between the surface of the connection area 22 on the first side 29 and the surface of the circuit board 2 on the second side 210 is smaller than the distance between the surface of the transmission area 21 on the first side 29 and the surface of the circuit board 2 on the second side 210.

[0113] In a specific embodiment, the thickness h1 of the above-mentioned circuit board 2 in the above-mentioned connection area 22 is less than or equal to 0.3mm, that is, h1≤0.3mm. The thickness h2 of the above-mentioned circuit board 2 in the above-mentioned transmission area 21 is greater than or equal to 0.5mm, that is, h2≥0.5mm. In a specific embodiment, the thickness difference △h between the above-mentioned circuit board 2 in the connection area 22 and the transmission area 21 is less than or equal to 0.5mm, △h≤0.5mm. The line width w1 of the signal line 241 in the connection area 22 is less than or equal to 50μm, that is, w1≤50μm. The line width w2 of the signal line 241 in the transmission area 21 is greater than or equal to 250μm, that is, w1≥250μm.

[0114] In the embodiment of the present application, the connection area 22 of the circuit board 2 covers the pinmap of the circuit board 2 . However, along the width direction of the circuit board 2 , the connection area 22 may or may not penetrate the circuit board 2 . Fig.21 Schematic diagram of a top view of the circuit board in the embodiment of the present application. Fig.16 and Fig.21 As shown, the circuit board 2 includes an extension direction X, a width direction Y and a thickness direction Z. The first direction X, the second direction Y and the thickness direction are perpendicular to each other.

[0115] like Fig.16 As shown, in one embodiment, the connection area 22 penetrates the circuit board 2 along the width direction of the circuit board 2, which is conducive to simplifying the preparation process of the circuit board 2 and improving the flexibility of the circuit board 2 in the connection area 22. Fig.21 As shown, in one embodiment, the connection area 22 does not penetrate the circuit board 2 along the width direction of the circuit board 2, that is, the edge of the circuit board 2 in the thickness direction of the connection area 22 also has an additional area, and the thickness of the additional area is greater than the thickness of the connection area 22. In a specific embodiment, the thickness of the additional area can be made the same as the thickness of the transmission area 21. This embodiment is conducive to improving the strength of the circuit board 2.

[0116] Based on the same concept, the present application also provides a method for preparing the circuit board 2. Fig. 22 This is a schematic diagram of the structure of a circuit board in the embodiment of the present application. The preparation method provided in this embodiment is used to prepare Fig. 22 Please refer to the circuit board 2 shown in Fig. 22 The circuit board 2 includes a transmission area 21 and a connection area 22, and the transmission area 21 is connected to the connection area 22. The preparation method of the circuit board 2 provided in the present application includes the following steps:

[0117] S101, forming a signal circuit pattern on a first metal layer L1 on a surface of a first flexible metal-clad plate FL1, and a second metal layer L2 is formed on a surface of the first flexible metal-clad plate FL1 away from the first metal layer L1;

[0118] The flexible metal-clad laminate in the present application includes a stacked metal layer and a dielectric layer, and the metal layer can specifically be a metal foil layer. The flexible metal-clad laminate can specifically include a single-sided metal-clad laminate and a double-sided metal-clad laminate. The single-sided metal-clad laminate is a laminate having a metal layer covered on one side of the dielectric layer, and the double-sided metal-clad laminate is a laminate having metal layers covered on both sides of the dielectric layer. The connection between the metal layer and the dielectric layer in the flexible metal-clad laminate is more reliable, and the use of the flexible metal-clad laminate to prepare the circuit board 2 is conducive to simplifying the preparation process of the circuit board 2. The above-mentioned first flexible metal-clad laminate FL1 is a double-sided metal-clad laminate. In a specific embodiment, the flexible metal-clad laminate in the present application can specifically be a flexible copper clad laminate (FCCL). In addition, the metal layer in the present application can be a copper layer, an aluminum layer, a silver layer, etc.

[0119] S102, laminating the third metal layer L3, the first adhesive layer BS1 and the first flexible metal-clad plate FL1 stacked in sequence, wherein the third metal layer L3 is located on a side of the first metal layer L1 away from the second metal layer L2;

[0120] The third metal layer L3 is fixed to the surface of the first flexible metal-clad substrate FL1 having the first metal layer L1 through the first adhesive layer BS1.

[0121] S103, preparing a conductive via, wherein the conductive via connects at least two layers among the first metal layer L1, the second metal layer L2 and the third metal layer L3;

[0122] The step of preparing the conductive hole may specifically include two steps: processing the hole and electroplating the metal layer. The step of processing the hole may be completed by mechanical drilling or laser drilling. For example, the conductive hole is formed by mechanical drilling, and the hole diameter of the conductive hole is between 4mil and 10mil; the conductive hole is formed by laser drilling, and the hole diameter of the conductive hole is between 2mil and 4mil. In addition, the conductive hole may specifically be a through hole or a blind hole. In the process of electroplating the metal layer in the hole, the metal layer may also be electroplated on the surface of the metal layer to thicken the metal layer. Which metal layers the conductive hole specifically connects is prepared according to the actual routing requirements.

[0123] S104, forming a circuit pattern on the third metal layer L3;

[0124] Specifically, the above-mentioned circuit pattern can be formed by an etching process. For example, the circuit pattern can be specifically connected to the pin 23 and can also be connected to the signal circuit pattern through a conductive hole.

[0125] S105, laminating the second flexible metal-clad plate FL2, the second adhesive layer BS2 and the third metal layer L3 stacked in sequence; the second flexible metal-clad plate FL2 includes a fourth metal layer L4, the fourth metal layer L4 is located on a surface away from the third metal layer L3, and the second flexible metal-clad plate FL2 and the second adhesive layer BS2 cover a portion of the transmission area 21;

[0126] The second flexible metal-clad plate FL2 is a single-sided metal-clad plate, and the fourth metal layer L4 of the second flexible metal-clad plate FL2 is located on the surface of the circuit board 2. The second flexible metal-clad plate FL2 and the second adhesive layer BS2 only cover part of the transmission area 21, so that the thickness of the circuit board 2 in the transmission area 21 is greater than the thickness in the connection area 22.

[0127] S106, forming a circuit pattern on the fourth metal layer L4.

[0128] Specifically, the circuit pattern may be formed by an etching process.

[0129] Before the above step S105, the method includes: disposing a blocking member 5 on the surface of the first metal layer L1;

[0130] The blocking member 5 may be a gasket or a blocking block. The blocking member 5 may block the second adhesive layer BS2 to prevent the second adhesive layer BS2 from flowing to the connection area 22. In particular, when the second adhesive layer BS2 is thicker, the bonding effect of the second flexible metal-clad plate FL2 may be improved, and the influence of the second adhesive layer BS2 on the third metal layer L3 of the connection area 22 may be reduced.

[0131] After the above step S105 , the following step is performed: removing the blocking member 5 .

[0132] Specifically, the depth-controlled drilling and milling technology can be used to remove the blocking member 5. This solution is conducive to the second flexible metal-clad plate and the second adhesive layer covering the transmission area more accurately and reliably.

[0133] In a specific embodiment, the signal line pattern formed in step S101 includes a signal line 241, the cross-sectional area of ​​the signal line 241 in the connection area 22 is smaller than the cross-sectional area of ​​the same signal line 241 in the transmission area 21, and the spacing between adjacent signal lines 241 in the connection area 22 is smaller than the spacing in the transmission area 21. This reduces the insertion loss of the circuit board and optimizes the impedance of the circuit board, so as to improve the density and rate of signal transmission of the circuit board.

[0134] Based on the same inventive concept, the present application also provides a method for preparing the circuit board 2. Fig.23 This is a schematic diagram of the structure of a circuit board in the embodiment of the present application. The preparation method provided in this embodiment is used to prepare Fig.23 Please refer to the circuit board 2 shown in Fig.23 The circuit board 2 includes a transmission area 21 and a connection area 22, and the transmission area 21 is connected to the connection area 22. The preparation method of the circuit board 2 provided in the present application includes the following steps:

[0135] Step S201, forming a signal circuit pattern on the first metal layer L1 on the surface of the first flexible metal-clad plate FL1, and the surface of the first flexible metal-clad plate FL1 away from the first metal layer L1 has a second metal layer L2;

[0136] Step S202, laminating the third metal layer L3, the first adhesive layer BS1 and the first flexible metal-clad plate FL1 stacked in sequence, wherein the third metal layer L3 is located on a side of the first metal layer L1 away from the second metal layer L2;

[0137] Step S203, preparing a conductive via, wherein the conductive via connects at least two layers among the first metal layer L1, the second metal layer L2 and the third metal layer L3;

[0138] Step S204, forming a circuit pattern on the second metal layer L2 of the first flexible metal-clad substrate FL1;

[0139] Step S205, laminating the fourth metal layer L4, the second adhesive layer BS2 and the second metal layer L2 stacked in sequence, wherein the fourth metal layer L4 covers a portion of the transmission area 21;

[0140] Step S206: forming a circuit pattern on the fourth metal layer L4.

[0141] In a specific embodiment, the signal line pattern formed in step S201 includes a signal line 241, the cross-sectional area of ​​the signal line 241 in the connection area 22 is smaller than the cross-sectional area of ​​the same signal line 241 in the transmission area 21, and the spacing between adjacent signal lines 241 in the connection area 22 is smaller than the spacing in the transmission area 21. This reduces the insertion loss of the circuit board and optimizes the impedance of the circuit board, so as to improve the density and rate of signal transmission of the circuit board.

[0142] Based on the same inventive concept, the present application also provides a method for preparing the circuit board 2. Fig.24 This is a schematic diagram of the structure of a circuit board in the embodiment of the present application. The preparation method provided in this embodiment is used to prepare Fig.24 Please refer to the circuit board 2 shown in Fig.24 The circuit board 2 includes a transmission area 21 and a connection area 22, and the transmission area 21 is connected to the connection area 22. The preparation method of the circuit board 2 provided in the present application includes the following steps:

[0143] Step S301, forming signal circuit patterns on the first metal layer L1 and the second metal layer L2 on both side surfaces of the first flexible metal-clad plate FL1, respectively, and the first metal layer L1 and the second metal layer L2 are respectively located on both side surfaces of the first flexible metal-clad plate FL1;

[0144] Step S302, laminating the third metal layer L3, the first adhesive layer BS1, the first flexible metal-clad plate FL1, the second adhesive layer BS2 and the fourth metal layer L4 stacked in sequence;

[0145] Step S303, preparing conductive holes to connect at least two layers among the first metal layer L1, the second metal layer L2, the third metal layer L3 and the fourth metal layer L4;

[0146] Step S304, forming a circuit pattern on the third metal layer L3 and the fourth metal layer L4 respectively;

[0147] Step S305, laminating the second flexible metal-clad plate FL2, the third adhesive layer BS3, the third metal layer L3, the first adhesive layer BS1, the first flexible metal-clad plate FL1, the second adhesive layer BS2, the fourth metal layer L4, the fourth adhesive layer BS4 and the third flexible metal-clad plate FL3 which are stacked in sequence; the second flexible metal-clad plate FL2 and the third flexible metal-clad plate FL3 respectively cover parts of the transmission area 21;

[0148] Step S306: the second flexible metal-clad plate FL2 includes a fifth metal layer L5, and the fifth metal layer L5 is located on a side away from the first flexible metal-clad plate FL1; the third flexible metal-clad plate FL3 includes a sixth metal layer L6, and the sixth metal layer L6 is located on a side away from the first flexible metal-clad plate FL1;

[0149] Step S307 , forming circuit patterns on the fifth metal layer L5 and the sixth metal layer L6 respectively.

[0150] In a specific embodiment, the signal line pattern formed in step S301 includes a signal line 241, the cross-sectional area of ​​the signal line 241 in the connection area 22 is smaller than the cross-sectional area of ​​the same signal line 241 in the transmission area 21, and the spacing between adjacent signal lines 241 in the connection area 22 is smaller than the spacing in the transmission area 21;

[0151] Based on the same inventive concept, the present application also provides a method for preparing the circuit board 2. Fig.25 This is a schematic diagram of the structure of a circuit board in the embodiment of the present application. The preparation method provided in this embodiment is used to prepare Fig.25 Please refer to the circuit board 2 shown in Fig.25 The circuit board 2 includes a transmission area 21 and a connection area 22, and the transmission area 21 is connected to the connection area 22. The preparation method of the circuit board 2 provided in the present application includes the following steps:

[0152] Step S401, forming a signal circuit pattern on the first metal layer L1 of the first flexible metal clad plate FL1 and the second metal layer L2 of the second flexible metal clad plate FL2, respectively, forming a circuit pattern on the third metal layer L3 of the first flexible metal clad plate FL1, the first metal layer L1 and the third metal layer L3 are respectively located on both side surfaces of the first flexible metal clad plate FL1, and the surface of the second flexible metal clad plate FL2 away from the second metal layer L2 has a fourth metal layer L4;

[0153] Step S402, laminating the fifth metal layer L5, the first adhesive layer BS1, the first flexible metal-clad plate FL1, the second adhesive layer BS2, and the second flexible metal-clad plate FL2 stacked in sequence, wherein the first metal layer L1 is adjacent to the first adhesive layer BS1, and the second metal layer L2 is adjacent to the second adhesive layer BS2;

[0154] Step S403, preparing conductive holes to connect at least two layers among the first metal layer L1, the second metal layer L2, the third metal layer L3, the fourth metal layer L4 and the fifth metal layer L5;

[0155] Step S404, forming a circuit pattern on the fourth metal layer L4;

[0156] Step S405 , laminating the sixth metal layer L6 , the third adhesive layer BS3 , and the second flexible metal-clad plate FL2 stacked in sequence, wherein the sixth metal layer L6 covers a portion of the transmission area 21 ;

[0157] Step S406: forming a circuit pattern on the sixth metal layer L6.

[0158] In a specific embodiment, the signal line pattern formed in step S401 includes a signal line 241, the cross-sectional area of ​​the signal line 241 in the connection area 22 is smaller than the cross-sectional area of ​​the same signal line 241 in the transmission area 21, and the spacing between adjacent signal lines 241 in the connection area 22 is smaller than the spacing in the transmission area 21. This reduces the insertion loss of the circuit board and optimizes the impedance of the circuit board, so as to improve the density and rate of signal transmission of the circuit board.

[0159] In the above embodiment, the preparation Fig.23 , Fig.24 and Fig.25 The several methods for preparing the circuit board 2 shown may also include the process of setting the blocking member 5 and removing the blocking member 5, and some related details can be referred to in the preparation Fig. 22 The method for preparing the circuit board 2 is shown.

[0160] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A circuit board, characterized in that: It includes a transmission area and a connection area, the connection area includes a bending area and a pin area, the bending area is located between the pin area and the transmission area, and the pin area is provided with a plurality of pins, wherein: The bending area is a flexible circuit board, and the thickness of the bending area is smaller than the thickness of the transmission area.

2. The circuit board according to claim 1, characterized in that The circuit board includes a signal line, and the cross-sectional area of ​​the signal line in the connection area is smaller than the cross-sectional area of ​​the same signal line in the transmission area.

3. The circuit board according to claim 1 or 2, characterized in that: The distance between adjacent signal lines located in the same layer in the transmission area is greater than the distance in the connection area.

4. The circuit board according to any one of claims 1 to 3, characterized in that: A length of the bending area along a direction from the pin area to the transmission area is greater than or equal to a preset value.

5. The circuit board according to claim 4, characterized in that: The preset value includes 60 mm.

6. The circuit board according to any one of claims 1 to 5, characterized in that: The pin area is a flexible circuit board.

7. The circuit board according to any one of claims 1 to 5, characterized in that: The pin area includes a rigid circuit board.

8. The circuit board according to claim 7, characterized in that: The bending zone includes a first bending zone and a second bending zone, the transmission zone includes a first transmission zone and a second transmission zone, the first bending zone is connected to the first transmission zone, the second bending zone is connected to the second transmission zone, the first transmission zone and the second transmission zone are stacked and have a gap; the pin zone is connected to the first bending zone and the second bending zone respectively.

9. The circuit board according to any one of claims 1 to 8, characterized in that: The circuit board includes a first side and a second side which are opposite to each other in the thickness direction; on the first side, the surface of the bending zone and the surface of the transmission zone are located in different planes; on the second side, the surface of the bending zone and the surface of the transmission zone are located in the same plane.

10. The circuit board according to any one of claims 1 to 8, characterized in that: The circuit board includes a first side and a second side which are opposite to each other in the thickness direction; on the first side, the surface of the bending zone and the surface of the transmission zone are located in different planes; on the second side, the surface of the bending zone and the surface of the transmission zone are located in different planes.

11. The circuit board according to any one of claims 1 to 10, characterized in that: The material of the dielectric layer includes at least one of modified polyimide, liquid crystal polymer, fluorinated ethylene propylene copolymer and polytetrafluoroethylene.

12. A method for preparing a circuit board, characterized in that: The circuit board comprises a transmission area and a connection area, the transmission area and the connection area are connected, and the preparation method comprises: A signal circuit pattern is formed on the first metal layer on the surface of the first flexible metal-clad plate, and a second metal layer is formed on the surface of the first flexible metal-clad plate away from the first metal layer; Laminating a third metal layer, a first adhesive layer and a first flexible metal-clad plate which are stacked in sequence, wherein the third metal layer is located on a side of the first metal layer away from the second metal layer; preparing a conductive hole, wherein the conductive hole connects at least two layers among the first metal layer, the second metal layer and the third metal layer; The second flexible metal-clad plate, the second adhesive layer and the third metal layer are laminated in sequence; the second flexible metal-clad plate includes a fourth metal layer, the fourth metal layer is located on the surface away from the third metal layer, and the second flexible metal-clad plate and the second adhesive layer cover part of the transmission area.

13. The preparation method according to claim 12, characterized in that: The second flexible metal-clad plate, the second adhesive layer and the third metal layer are sequentially laminated by lamination; the second flexible metal-clad plate includes a fourth metal layer, the fourth metal layer is located on a surface away from the third metal layer, and the second flexible metal-clad plate and the second adhesive layer cover a portion of the transmission area, and the prior includes: Disposing a blocking member at the connection area on the surface of the first metal layer; After that include: The blocking member is removed.

14. The preparation method according to claim 12 or 13, characterized in that: The signal line pattern includes a signal line, the cross-sectional area of ​​the signal line in the connection area is smaller than the cross-sectional area of ​​the same signal line in the transmission area, and the spacing between adjacent signal lines in the connection area is smaller than the spacing between adjacent signal lines in the transmission area.

15. A method for preparing a circuit board, characterized in that: The circuit board comprises a transmission area and a connection area, the transmission area and the connection area are connected, and the preparation method comprises: A signal circuit pattern is formed on the first metal layer on the surface of the first flexible metal-clad plate, and a second metal layer is formed on the surface of the first flexible metal-clad plate away from the first metal layer; Laminating the third metal layer, the first adhesive layer and the first flexible metal-clad plate stacked in sequence, wherein the third metal layer is located on a side of the first metal layer facing away from the second metal layer; preparing a conductive hole, wherein the conductive hole connects at least two layers among the first metal layer, the second metal layer and the third metal layer; The fourth metal layer, the second adhesive layer and the second metal layer stacked in sequence are laminated, and the fourth metal layer covers a portion of the transmission area.

16. The preparation method according to claim 15, characterized in that: The signal line pattern includes a signal line, the cross-sectional area of ​​the signal line in the connection area is smaller than the cross-sectional area of ​​the same signal line in the transmission area, and the spacing between adjacent signal lines in the connection area is smaller than the spacing between adjacent signal lines in the transmission area.

17. A method for preparing a circuit board, characterized in that: The circuit board comprises a transmission area and a connection area, the transmission area and the connection area are connected, and the preparation method comprises: Signal circuit patterns are formed on the first metal layer and the second metal layer on both side surfaces of the first flexible metal-clad plate, respectively, and the first metal layer and the second metal layer are respectively located on both side surfaces of the first flexible metal-clad plate; Laminating the third metal layer, the first adhesive layer, the first flexible metal-clad plate, the second adhesive layer and the fourth metal layer stacked in sequence; Prepare conductive holes to connect at least two of the first metal layer, the second metal layer, the third metal layer and the fourth metal layer; Laminating the second flexible metal-clad plate, the third adhesive layer, the third metal layer, the first adhesive layer, the first flexible metal-clad plate, the second adhesive layer, the fourth metal layer, the fourth adhesive layer and the third flexible metal-clad plate which are stacked in sequence; the second flexible metal-clad plate and the third flexible metal-clad plate respectively cover parts of the transmission area; The second flexible metal clad laminate includes a fifth metal layer, and the fifth metal layer is located on a side away from the first flexible metal clad laminate; the third flexible metal clad laminate includes a sixth metal layer, and the sixth metal layer is located on a side away from the first flexible metal clad laminate.

18. The preparation method according to claim 17, characterized in that: The signal line pattern includes a signal line, the cross-sectional area of ​​the signal line in the connection area is smaller than the cross-sectional area of ​​the same signal line in the transmission area, and the spacing between adjacent signal lines in the connection area is smaller than the spacing between adjacent signal lines in the transmission area.

19. A method for preparing a circuit board, characterized in that: The circuit board comprises a transmission area and a connection area, the transmission area and the connection area are connected, and the preparation method comprises: Signal circuit patterns are formed on the first metal layer of the first flexible metal clad plate and the second metal layer of the second flexible metal clad plate, respectively; a circuit pattern is formed on the third metal layer of the first flexible metal clad plate, the first metal layer and the third metal layer are respectively located on both side surfaces of the first flexible metal clad plate, and the surface of the second flexible metal clad plate away from the second metal layer has a fourth metal layer; Laminating the fifth metal layer, the first adhesive layer, the first flexible metal-clad plate, the second adhesive layer and the second flexible metal-clad plate stacked in sequence, wherein the first metal layer is adjacent to the first adhesive layer, and the second metal layer is adjacent to the second adhesive layer; Prepare conductive holes to connect at least two layers among the first metal layer, the second metal layer, the third metal layer, the fourth metal layer and the fifth metal layer; The sixth metal layer, the third adhesive layer and the second flexible metal-clad plate stacked in sequence are laminated, and the sixth metal layer covers a portion of the transmission area.

20. The preparation method according to claim 19, characterized in that: The signal line pattern includes a signal line, the cross-sectional area of ​​the signal line in the connection area is smaller than the cross-sectional area of ​​the same signal line in the transmission area, and the spacing between adjacent signal lines in the connection area is smaller than the spacing between adjacent signal lines in the transmission area.

21. An electronic component, characterized in that: The invention comprises a printed circuit board and the circuit board as claimed in any one of claims 1 to 11, wherein at least one connection area of ​​the circuit board is electrically connected to the printed circuit board.

22. An electronic device, characterized in that: It comprises a housing and the electronic component as claimed in claim 21, wherein the electronic component is arranged in the housing.

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