Flexible circuit board, electronic equipment and preparation method

Abstract

The invention provides a flexible circuit board, electronic equipment and a preparation method, and relates to the technical field of electronic circuits, and the flexible circuit board comprises a first isolation layer, a first conductive layer and a second isolation layer which are stacked from top to bottom; the first conductive layer comprises a first part and a second part, the first part is provided with a plurality of first slots, the second part comprises a plurality of deformable structures, the plurality of deformable structures are in one-to-one correspondence with the plurality of first slots, and the deformable structures extend outwards from the interiors of the first slots; the first isolation layer or the second isolation layer is provided with a plurality of second open grooves in one-to-one correspondence with the plurality of deformable structures, and the plurality of deformable structures penetrate through the plurality of second open grooves and protrude out of the surface of the first isolation layer or the second isolation layer. According to the FPC provided by the embodiment of the invention, the spacing distance between the FPC and the PCB after the FPC and the PCB are assembled can be reduced so as to reduce the thickness of the electronic equipment, and meanwhile, the connection reliability of the FPC and the PCB can also be improved.

Description

Technical Field

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

[0002] Flexible printed circuit board (FPC), also known as flexible circuit board or soft board, is a highly reliable flexible printed circuit board made of a series of film materials such as polyimide or polyester film as the base material. Because of its lightness, freedom of bending, winding and folding, it has been increasingly used in mobile communications, laptops, computers and other products.

[0003] One of the functions of FPC is to connect different printed circuit boards (PCBs) in electronic devices, or to connect other devices to the PCB.

[0004] Currently, the FPC and PCB can be connected by installing connectors on the FPC and PCB, for example, installing male and female connectors on the FPC and PCB respectively, or installing springs on the FPC. Since the connector itself is relatively thick, the distance between the FPC and PCB after assembly is relatively large, resulting in a relatively thick electronic device.

[0005] In order to reduce the spacing between the FPC and the PCB after assembly, the FPC and the PCB can be connected by welding. However, the solder is easy to break, resulting in low reliability of the connection between the FPC and the PCB.

[0006] Therefore, there is an urgent need for an FPC that can reduce the spacing distance between the FPC and the PCB after the two are assembled and improve the connection reliability between the FPC and the PCB. Summary of the invention

[0007] The present application provides a flexible circuit board, an electronic device and a preparation method. The FPC provided in the embodiment of the present application can reduce the spacing distance between the FPC and the PCB after the two are assembled to reduce the thickness of the electronic device, and can also improve the connection reliability between the FPC and the PCB.

[0008] In order to achieve the above objectives, this application adopts the following technical solutions:

[0009] In a first aspect, a flexible circuit board is provided, comprising: a first isolation layer, a first conductive layer, and a second isolation layer stacked from top to bottom; the first conductive layer comprises a first part and a second part, the first part is provided with a plurality of first grooves, the second part comprises a plurality of deformable structures, the plurality of deformable structures correspond one-to-one to the plurality of first grooves, and the deformable structures extend outward from the inside of the first grooves; a plurality of second grooves corresponding one-to-one to the plurality of deformable structures are provided on the first isolation layer or the second isolation layer, the plurality of deformable structures pass through the plurality of second grooves and protrude from the surface of the first isolation layer or the second isolation layer.

[0010] In the embodiment of the present application, when the FPC and the PCB are assembled, the FPC and the PCB are in contact and pressed, and the PCB will press the multiple deformable structures back into the groove formed by the second slot and the first slot corresponding to the second slot. Therefore, compared with the method of installing a connector to connect the FPC and the PCB, the spacing between the FPC and the PCB after the two are assembled in the embodiment of the present application is smaller, and the thickness of the electronic device in the direction perpendicular to the display screen is also smaller, that is, the thickness of the electronic device can be reduced. In addition, since the multiple deformable structures are not installed on the FPC, but are part of the first conductive layer, no additional thickness will be introduced, and the deformable structures are not easy to break, and the connection reliability between the FPC and the PCB is higher. It can be seen that the FPC provided in the embodiment of the present application can reduce the spacing between the FPC and the PCB after the two are assembled to reduce the thickness of the electronic device, and can also improve the connection reliability between the FPC and the PCB.

[0011] In a possible implementation of the first aspect, the deformable structure is in a sheet shape. In an embodiment of the present application, after the FPC and the PCB are assembled, the sheet-shaped deformable structure has a larger contact area with the PCB, which can reduce the contact resistance between the FPC and the PCB.

[0012] In a possible implementation of the first aspect, the deformable structure includes an inclined portion and a flat portion, one end of the inclined portion is connected to the interior of the first groove, and the other end is connected to the flat portion, there is an angle less than 90 degrees between the inclined portion and the first portion, and the flat portion is parallel to the first portion.

[0013] In the embodiment of the present application, since the flattened portion of the deformable structure is parallel to the first portion of the first conductive layer, and when the FPC is assembled with the PCB, the PCB is parallel to the first portion of the first conductive layer in the FPC, the PCB is also parallel to the flattened portion of the deformable structure. In this way, after the FPC is assembled with the PCB, the flattened portion of the deformable structure can contact the PCB to the greatest extent, so as to further reduce the contact resistance between the FPC and the PCB.

[0014] In a possible implementation manner of the first aspect, a height of the multiple deformable structures protruding from the surface of the first isolation layer or the second isolation layer is greater than 0.

[0015] In the embodiment of the present application, a plurality of deformable structures are provided to protrude from the surface of the first isolation layer or the second isolation layer to a height greater than 0, so as to ensure that the deformable structures of the FPC are in good contact with the PCB after the FPC and the PCB are assembled.

[0016] In a possible implementation of the first aspect, the flexible circuit board also includes: a first adhesive layer, on which a plurality of third grooves corresponding one-to-one to the plurality of deformable structures are arranged; when the plurality of second grooves are arranged on the first isolation layer, the first adhesive layer is located between the first conductive layer and the second isolation layer; when the plurality of second grooves are arranged on the second isolation layer, the first adhesive layer is located between the first conductive layer and the first isolation layer.

[0017] In an embodiment of the present application, the first adhesive layer is used to bond the first conductive layer and the second isolation layer or to bond the first conductive layer and the first isolation layer, and the first adhesive layer may be provided with a plurality of third grooves corresponding one-to-one to the plurality of deformable structures. In this way, it is possible to avoid the situation where the deformable structure is stuck by the first adhesive layer and cannot contact the PCB.

[0018] In a possible implementation of the first aspect, the flexible circuit board also includes: a second conductive layer and a third isolation layer; when the first isolation layer is provided with the plurality of second grooves, the second conductive layer is provided below the second isolation layer, the third isolation layer is provided below the second conductive layer, and the upper surface of the second conductive layer is provided with at least one protruding structure, and the protruding structure is in contact with the lower surface of the first conductive layer; when the second isolation layer is provided with the plurality of second grooves, the second conductive layer is provided above the first isolation layer, the third isolation layer is provided above the second conductive layer, and the lower surface of the second conductive layer is provided with at least one protruding structure, and the protruding structure is in contact with the upper surface of the first conductive layer.

[0019] In the embodiment of the present application, an FPC with a double-sided conductive layer is provided. The FPC with a double-sided conductive layer includes not only a first conductive layer, but also a second conductive layer in contact with the first conductive layer through a protruding structure. The design of the double-sided conductive layer can greatly reduce the surface area of ​​the FPC.

[0020] In a possible implementation manner of the first aspect, the elasticity of the first conductive layer is stronger than the elasticity of the second conductive layer, and the conductivity of the second conductive layer is stronger than the conductivity of the first conductive layer.

[0021] In the embodiment of the present application, the first conductive layer has better elasticity than the second conductive layer, and the multiple deformable structures distributed on the first conductive layer have good elasticity. When the FPC is assembled with the PCB, the deformable structure is deformed under the action of external force. Since the deformable structure has good elasticity, the FPC will provide an action force to the PCB, and the PCB will provide a reaction force to the FPC. An interaction force is generated between the FPC and the PCB, making the contact between the FPC and the PCB more compact and reliable. After the PCB is removed, the deformable structure recovers its deformation and can be reused many times. The conductivity of the second conductive layer is stronger than that of the first conductive layer, and the second conductive layer can achieve good transmission of electrical signals. The conductive pattern may not be designed on the first conductive layer, but a conductive pattern may be designed on the second conductive layer with better conductive performance. In this way, the FPC in this embodiment can take into account both the elasticity of the deformable structure and the conductivity of the FPC.

[0022] In a possible implementation manner of the first aspect, the material of the first conductive layer is a copper alloy, and the material of the second conductive layer is copper.

[0023] In a possible implementation manner of the first aspect, the deformable structure is an elastic structure.

[0024] In the embodiment of the present application, when the deformable structure is an elastic structure, when the FPC is assembled with the PCB, the deformable structure on the FPC is deformed under the action of an external force, and the FPC provides a reaction force to the PCB under the action of the elastic force of the deformable structure, so that the contact between the FPC and the PCB is tighter and more reliable. After the PCB is removed, the deformable structure will restore its deformation, and the FPC can be reused.

[0025] In a possible implementation of the first aspect, the flexible circuit board also includes: a reinforcement plate, which completely covers the area in the first conductive layer where the deformable structure is distributed; when the first isolation layer is provided with the multiple second grooves, the reinforcement plate is arranged below the isolation layer farthest from the first isolation layer; when the second isolation layer is provided with the multiple second grooves, the reinforcement plate is arranged above the isolation layer farthest from the second isolation layer.

[0026] In an embodiment of the present application, a reinforcement plate may be provided, which completely covers the area in the first conductive layer where the deformable structure is distributed. In this way, the reinforcement plate may provide support for the FPC to prevent the FPC from being lifted up and away from the PCB under the elastic force of the deformable structure, thereby ensuring good contact between the FPC and the PCB.

[0027] In a possible implementation manner of the first aspect, the material of the first conductive layer is copper.

[0028] In a second aspect, an electronic device is provided, comprising a printed circuit board and a flexible circuit board as described in the first aspect or any possible implementation of the first aspect; a surface of the printed circuit board is provided with a plurality of solder pads corresponding one-to-one to the plurality of deformable structures, the flexible circuit board is stacked and pressed tightly with the printed circuit board, and during the process of stacking and pressing the flexible circuit board with the printed circuit board, the plurality of solder pads are electrically connected with the plurality of deformable structures.

[0029] In an embodiment of the present application, the multiple deformable structures on the FPC correspond one-to-one to the multiple pads on the PCB, and in the process of stacking and pressing the FPC and the PCB together, the multiple pads and the multiple deformable structures correspond one-to-one to achieve electrical connection, thereby achieving electrical connection between the FPC and the PCB.

[0030] In a possible implementation manner of the second aspect, the printed circuit board has a plurality of grooves, and the plurality of pads are disposed in the plurality of grooves in a one-to-one correspondence.

[0031] In the embodiment of the present application, after the FPC and the PCB are stacked and pressed together, the deformable structure on the FPC will extend into the groove of the PCB and contact the pad in the groove. In this way, compared with the spacing between the FPC and the PCB after assembly without a groove, the spacing between the FPC and the PCB after assembly in the present application is smaller, and the thickness of the electronic device in the direction perpendicular to the display screen is smaller, that is, the thickness of the electronic device can be further reduced.

[0032] In a possible implementation manner of the second aspect, a height of the multiple deformable structures protruding from the surface of the first isolation layer or the second isolation layer is greater than or equal to a depth of the groove.

[0033] In an embodiment of the present application, the height of multiple deformable structures protruding from the surface of the first isolation layer or the second isolation layer is greater than or equal to the depth of the groove. In this way, after the FPC and the PCB are stacked and pressed together, the deformable structure is fully extended into the groove, and the deformable structure contacts the pad and deforms, or the deformable structure just contacts the pad, ensuring that the deformable structure is in good contact with the pad in the groove.

[0034] In a third aspect, a method for preparing a flexible circuit board is provided, comprising:

[0035] Providing a first isolation layer, wherein the first isolation layer has a plurality of second grooves;

[0036] transferring the first isolation layer onto the prefabricated first conductive layer;

[0037] Processing the first conductive layer located in the plurality of second grooves to form a plurality of deformable structures corresponding to the plurality of second grooves one by one, and a plurality of first grooves corresponding to the plurality of deformable structures one by one, wherein the deformable structures extend outward from the inside of the first grooves, pass through the second grooves and protrude from the surface of the first isolation layer;

[0038] transferring the first insulating layer and the processed first conductive layer to a prefabricated structure, wherein the prefabricated structure comprises at least a second insulating layer, and the first conductive layer is located between the first insulating layer and the second insulating layer;

[0039] or,

[0040] Providing a second isolation layer, wherein the second isolation layer has a plurality of second grooves;

[0041] transferring the second isolation layer onto the prefabricated first conductive layer;

[0042] The first conductive layer located within the plurality of second grooves is processed to form a plurality of deformable structures corresponding one-to-one to the plurality of second grooves, and a plurality of first grooves corresponding one-to-one to the plurality of deformable structures, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the second isolation layer.

[0043] In a possible implementation manner of the third aspect, processing the first conductive layer located in the plurality of second grooves to form a plurality of deformable structures corresponding one-to-one to the plurality of second grooves, and a plurality of first grooves corresponding one-to-one to the plurality of deformable structures, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the first isolation layer, including:

[0044] etching the first conductive layer in the second groove to form an intermediate structure, wherein an edge of the intermediate structure is not completely connected to the first conductive layer;

[0045] Using a mold to punch the intermediate structure to form a plurality of deformable structures corresponding to the plurality of second grooves one by one, and a plurality of first grooves corresponding to the plurality of deformable structures one by one, wherein the deformable structures extend outward from the inside of the first grooves, pass through the second grooves and protrude from the surface of the first isolation layer;

[0046] or,

[0047] The first conductive layer located in the plurality of second grooves is processed to form a plurality of deformable structures corresponding to the plurality of second grooves one by one, and a plurality of first grooves corresponding to the plurality of deformable structures one by one, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the second isolation layer, comprising:

[0048] etching the first conductive layer in the second groove to form an intermediate structure, wherein an edge of the intermediate structure is not completely connected to the first conductive layer;

[0049] The intermediate structure is punched by a mold to form a plurality of deformable structures corresponding one-to-one to the plurality of second grooves, and a plurality of first grooves corresponding one-to-one to the plurality of deformable structures, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the second isolation layer.

[0050] In a possible implementation manner of the third aspect, when the prefabricated structure includes at least a second isolation layer, the prefabricated structure is prepared by the following steps:

[0051] providing a second conductive layer;

[0052] forming the second isolation layer on the second conductive layer;

[0053] forming a first adhesive layer on the second isolation layer, wherein the first adhesive layer has third grooves corresponding to the plurality of deformable structures one by one;

[0054] After transferring the first isolation layer and the processed first conductive layer to the prefabricated structure, the method further includes:

[0055] A through hole is provided on the second conductive layer, penetrating the second conductive layer, the second isolation layer and the first adhesive layer;

[0056] forming a protruding structure in the through hole, the protruding structure being in contact with both the first conductive layer and the second conductive layer;

[0057] transferring all the prepared film layers onto the prefabricated third isolation layer, wherein the second conductive layer is in contact with the third isolation layer;

[0058] or,

[0059] In the case where the prefabricated structure comprises at least a first isolation layer, the prefabricated structure is prepared by the following steps:

[0060] providing a second conductive layer;

[0061] forming the first isolation layer on the second conductive layer;

[0062] forming a first adhesive layer on the first isolation layer, wherein the first adhesive layer has third grooves corresponding to the plurality of deformable structures one by one;

[0063] After transferring the second isolation layer and the processed first conductive layer to the prefabricated structure, the method further comprises:

[0064] A through hole is formed on the second conductive layer, penetrating the second conductive layer, the first isolation layer and the first adhesive layer;

[0065] forming a protruding structure in the through hole, the protruding structure being in contact with both the first conductive layer and the second conductive layer;

[0066] All the prepared film layers are transferred onto the prefabricated third isolation layer, and the second conductive layer is in contact with the third isolation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a schematic diagram of a three-dimensional structure of an electronic device in an embodiment of the present application, which is a non-folding mobile phone;

[0068] Figure 2 for Figure 1 A schematic diagram of a three-dimensional structure of a connection between an FPC and a PCB in an electronic device shown;

[0069] Figure 3 The electronic device of the embodiment of the present application is a three-dimensional structural schematic diagram of a foldable mobile phone;

[0070] Figure 4 for Figure 3 A schematic diagram of a three-dimensional structure of FPC connecting different PCBs in an electronic device shown;

[0071] Figure 5 For along Figure 4 The cross-sectional view of FPC connected to different PCBs in the AA` direction is shown;

[0072] Figure 6 This is a schematic diagram of a three-dimensional structure of a flat FPC in an embodiment of the present application;

[0073] Figure 7 For along Figure 6 A cross-sectional view of the FPC in the BB` direction shown;

[0074] Figure 8 is a cross-sectional view of the FPC when the second slot is provided in the second isolation layer;

[0075] Fig. 9 For along Figure 6 Another cross-sectional view of the FPC in the BB` direction shown;

[0076] Fig.10 Another cross-sectional view of the FPC when the second slot is disposed in the second isolation layer;

[0077] Fig.11 For along Figure 6 Another cross-sectional view of the FPC in the BB' direction shown;

[0078] Fig.12 is another cross-sectional view of the FPC in the case where the second slot is disposed in the second isolation layer;

[0079] Fig.13 For along Figure 6 Another cross-sectional view of the FPC in the BB' direction shown;

[0080] Fig.14 is another cross-sectional view of the FPC in the case where the second slot is provided in the second isolation layer;

[0081] Fig.15 This is a schematic diagram of the three-dimensional structure of the PCB according to an embodiment of the present application;

[0082] Fig.16 For along Fig.15 Cross-sectional view of PCB in CC` direction;

[0083] Fig.17 It is a cross-sectional view when the groove of the PCB is hemispherical;

[0084] Fig.18 For the preparation of Figure 7 A schematic diagram of a process for preparing an FPC shown;

[0085] Fig.19 For Fig.18 A schematic diagram of the film structure during the preparation process corresponding to the preparation method shown;

[0086] Fig. 20 for Fig.18 Specific structural diagram of step S12;

[0087] Fig.21 for Fig.19 (3) A top view of the membrane structure shown;

[0088] Fig. 22 for Fig.19 (3) Another top view of the membrane structure shown;

[0089] Fig.23 For preparation Fig.11 A schematic diagram of a process for preparing an FPC shown;

[0090] Fig.24 For Fig.23A schematic diagram of the film structure during the preparation process corresponding to the preparation method shown;

[0091] Fig.25 For Fig.23 A schematic flow chart of a specific method for preparing the prefabricated structure in step S131 is shown;

[0092] Fig.26 For preparation Figure 8 A schematic diagram of a process for preparing an FPC shown;

[0093] Fig. 27 for Fig.26 Specific structural diagram of step S32;

[0094] Fig.28 For preparation Fig.12 A schematic diagram of a process for preparing an FPC shown;

[0095] Fig.29 For Fig.28 The flowchart of the specific preparation method of the prefabricated structure in step S331 is shown. DETAILED DESCRIPTION

[0096] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0097] In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0098] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this embodiment, unless otherwise specified, "plurality" means two or more.

[0099] It should be noted in advance that the FPC mentioned in the embodiments of the present application stands for flexible circuit board, and the PCB stands for printed circuit board.

[0100] The FPC provided in the embodiment of the present application can be applied to electronic devices. The electronic devices can be desktop computers, laptops, tablet computers, ultra-mobile personal computers (UMPC), handheld computers, walkie-talkies, netbooks, POS machines, personal digital assistants (PDA), and other mobile terminals, fixed terminals, or foldable devices with FPC.

[0101] The electronic devices provided in the embodiments of the present application may include, but are not limited to, mobile phones, tablet computers, laptop computers, ultra-mobile personal computers (UMPCs), handheld computers, walkie-talkies, netbooks, POS machines, personal digital assistants (PDAs), driving recorders, security equipment, and other mobile or fixed terminals.

[0102] For ease of description, the embodiments of the present application are described by taking the electronic device as a non-folding mobile phone or a folding mobile phone as an example.

[0103] Figure 1 The electronic device 100 of the embodiment of the present application is a three-dimensional structural schematic diagram of a non-folding mobile phone. Figure 2 for Figure 1 The three-dimensional structure diagram of the connection between FPC10 and PCB20 in the electronic device 100 is shown. Figure 2 As shown, one function of the FPC 10 is to connect other devices (not shown in the figure) located on the back side of the PCB 20 in the electronic device to the PCB 20 .

[0104] Figure 3 The electronic device 200 of the embodiment of the present application is a three-dimensional structural schematic diagram of a foldable mobile phone. Figure 4 for Figure 3 A schematic diagram of a three-dimensional structure of an FPC 10 connected to different PCBs 20 in an electronic device shown; Figure 5 For along Figure 4 The cross-sectional view of FPC10 connected to different PCB20 in the AA' direction is shown. Figure 4 and Figure 5 As shown, another function of the FPC 10 is to connect different PCBs 20 in the electronic device 200. The FPC 10 can be bent. Figure 3 In the folded state shown, FPC10 is Figure 4 and Figure 5 The FPC 10 is shown in a bent shape; when the electronic device 200 is in an unfolded state, the FPC 10 is flat.

[0105] At present, the FPC and PCB can be connected by installing connectors on the FPC and PCB. For example, a board-to-board connector can be used for connection. The male and female heads of the board-to-board connector are installed on the FPC and PCB respectively. The male and female heads are plugged in to achieve the connection between the FPC and the PCB. However, in this way, the thickness of the male and female heads after plugging in is relatively large. Therefore, the distance between the FPC and the PCB after assembly is relatively large. For example, a spring clip can be used for connection. The spring clip is installed on the FPC. The spring clip on the FPC is connected to the pad on the PCB to achieve the connection between the FPC and the PCB. However, in this way, the spring clip itself has a certain thickness. Therefore, the distance between the FPC and the PCB after assembly is relatively large. Since the connector itself is relatively thick, the distance between the FPC and the PCB after assembly is relatively large, resulting in a relatively thick electronic device.

[0106] In order to reduce the spacing between the FPC and the PCB after assembly, the FPC and the PCB can be connected by welding, but the soldering is prone to breakage at the connection between the FPC and the PCB, and the reliability is not high.

[0107] Therefore, there is an urgent need for an FPC that can reduce the spacing between the FPC and the PCB after the two are assembled and improve the connection reliability between the FPC and the PCB.

[0108] In order to solve the above problems, the present application provides a new type of FPC. Figure 6 Schematic diagram of the three-dimensional structure of the FPC 10 in the embodiment of the present application in a flat shape. Figure 7 For along Figure 6 A cross-sectional view of the flexible circuit board 10 in the BB' direction shown; Figure 8 It is a cross-sectional view of the FPC 10 when the second groove 1002 is disposed in the second isolation layer 103 .

[0109] In the embodiment of the present application, the flexible circuit board 10 includes: a first isolation layer 101, a first conductive layer 102, and a second isolation layer 103 stacked from top to bottom; the first conductive layer 102 includes a first part 1021 and a second part, the first part 1021 is provided with a plurality of first grooves 1001, the second part includes a plurality of deformable structures 1022, the plurality of deformable structures 1022 correspond one-to-one to the plurality of first grooves 1001, and the deformable structures 1022 extend outward from the inside of the first grooves 1001; the first isolation layer 101 or the second isolation layer 103 is provided with a plurality of second grooves 1002 corresponding one-to-one to the plurality of deformable structures 1022, the plurality of deformable structures 1022 pass through the plurality of second grooves 1002 and protrude from the surface of the first isolation layer 101 or the second isolation layer 103.

[0110] In this embodiment, when the FPC10 and the PCB20 are assembled, the FPC10 and the PCB20 are in contact and pressed, and the PCB20 will press the multiple deformable structures 1022 back into the groove formed by the second groove 1002 and the first groove 1001 corresponding to the second groove 1002. Therefore, compared with the method of connecting the FPC10 and the PCB20 by installing a connector, the spacing between the FPC10 and the PCB20 after assembly is smaller, and the thickness of the electronic device in the direction perpendicular to the display screen is also smaller, that is, the thickness of the electronic device can be reduced. And because the second part of the first conductive layer 102 includes multiple deformable structures 1022, the multiple deformable structures 1022 are not installed on the FPC10, but are part of the first conductive layer 102, and no additional thickness will be introduced, and the deformable structures 1022 are not easy to break, so the connection reliability between the FPC10 and the PCB20 is high. It can be known that the FPC10 provided in the embodiment of the present application can reduce the spacing distance between the FPC10 and the PCB20 after the two are assembled to reduce the thickness of the electronic device, and can also improve the connection reliability between the FPC10 and the PCB20.

[0111] It should be noted that the shape of the second slot 1002 is as follows: Figure 6 As shown, it may be a rectangular parallelepiped. Of course, the shape of the second slot 1002 may also be a cylindrical shape, a cube shape, etc. Figure 6 The shape of the second slot 1002 shown in the figure is only an example and is not intended to limit the shape of the second slot 1002 in the embodiment of the present application. The shape of the first slot 1001 can be the same as the shape of the second slot 1002, which will not be described in detail in this embodiment.

[0112] The specific film layer structure of the FPC 10 provided in the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0113] The FPC 10 provided in the embodiment of the present application is roughly divided into two types, one is an FPC 10 with a single-sided conductive layer, and the other is an FPC 10 with a double-sided conductive layer.

[0114] First, the FPC 10 having a single-sided conductive layer will be described in detail.

[0115] See also Figure 7 or Figure 8The FPC 10 with a single-sided conductive layer includes a first isolation layer 101, a first conductive layer 102, and a second isolation layer 103 stacked from top to bottom. The first conductive layer 102 is disposed between the first isolation layer 101 and the second isolation layer 103 to protect the first conductive layer 102 from interference from the external environment. The first conductive layer 102 includes a first portion 1021 provided with a plurality of first slots 1001, and a second portion including a plurality of deformable structures 1022. The plurality of deformable structures 1022 correspond to the plurality of first slots 1001 one by one, and the plurality of deformable structures 1022 correspond to the plurality of second slots 1002 on the first isolation layer 101 or the second isolation layer 103 one by one. The deformable structure 1022 extends outward from the inside of the first slot 1001, passes through the plurality of second slots 1002 on the first isolation layer 101 or the second isolation layer 103, and protrudes from the surface of the first isolation layer 101 or the second isolation layer 103.

[0116] See also Figure 7 or Figure 8 In a possible implementation, the flexible circuit board 10 further includes: a first adhesive layer 104, on which a plurality of third grooves 1003 corresponding one to one with the plurality of deformable structures 1022 are arranged; when a plurality of second grooves 1002 are arranged on the first isolation layer 101, the first adhesive layer 104 is located between the first conductive layer 102 and the second isolation layer 103; when a plurality of second grooves 1002 are arranged on the second isolation layer 103, the first adhesive layer 104 is located between the first conductive layer 102 and the first isolation layer 101.

[0117] Specifically, if Figure 7 As shown, when a plurality of second slots 1002 are provided on the first isolation layer 101, the first adhesive layer 104 is located between the first conductive layer 102 and the second isolation layer 103, and is used to bond the first conductive layer 102 and the second isolation layer 103. The first adhesive layer 104 may be provided with a plurality of third slots 1003 corresponding to the plurality of deformable structures 1022, so that the deformable structures 1022 may be prevented from being stuck by the first adhesive layer 104 and unable to contact the PCB 20.

[0118] Realistically, the first conductive layer 102 and the first isolation layer 101 can also be bonded together by an adhesive layer (not shown in the figure), and the adhesive layer should be provided with grooves corresponding to the multiple second grooves 1002 one by one, so that the multiple deformable structures 1022 protrude from the surface of the first isolation layer 101.

[0119] like Figure 8As shown, when a plurality of second slots 1002 are provided on the second isolation layer 103, the first adhesive layer 104 is located between the first conductive layer 102 and the first isolation layer 101, and is used to bond the first conductive layer 102 and the first isolation layer 101. A plurality of third slots 1003 corresponding to the plurality of deformable structures 1022 are provided on the first adhesive layer 104, so that the deformable structure 1022 can be prevented from being stuck by the first adhesive layer 104 and unable to contact the PCB 20.

[0120] Realistically, the first conductive layer 102 and the second isolation layer 103 can also be bonded together by an adhesive layer (not shown in the figure), and the adhesive layer should be provided with grooves corresponding to the multiple second grooves 1002 one by one, so that the multiple deformable structures 1022 protrude from the surface of the second isolation layer 103.

[0121] It should be noted that the shape of the third slot 1003 may be the same as the shape of the second slot 1002 , and reference may be made to the description of the second slot 1002 , which will not be repeated here.

[0122] See also Fig. 9 or Fig.10 In a possible implementation, the flexible circuit board 10 further includes: a reinforcing plate 105, which completely covers the area in the first conductive layer 102 where the deformable structure 1022 is distributed; when a plurality of second slots 1002 are provided on the first isolation layer 101, the reinforcing plate 105 is provided below the isolation layer farthest from the first isolation layer 101; when a plurality of second slots 1002 are provided on the second isolation layer 103, the reinforcing plate 105 is provided above the isolation layer farthest from the second isolation layer 103.

[0123] Specifically, when the deformable structure 1022 is an elastic structure, after the FPC10 and the PCB20 are assembled, the deformable structure 1022 of the FPC10 is deformed under the action of an external force. After the external force is removed, the elastic force of the deformable structure 1022 will generate a force on the PCB20. Correspondingly, the PCB20 will also generate a reaction force on the deformable structure 1022. The deformable structure 1022 of the FPC10 may lift up the FPC10 under the reaction force of the PCB20, so that the FPC10 is partially or completely away from the PCB20, resulting in the deformable structure 1022 of the FPC10 being unable to contact the PCB20. To this end, a reinforcing plate 105 can be provided, which completely covers the area in the first conductive layer 102 where the deformable structure 1022 is distributed. In this way, the reinforcing plate 105 can provide support for the FPC 10 to prevent the FPC 10 from being partially or completely lifted away from the PCB 20, thereby ensuring good contact between the FPC 10 and the PCB 20.

[0124] like Fig. 9As shown, when a plurality of second slots 1002 are provided on the first isolation layer 101, the reinforcing plate 105 is provided below the second isolation layer 103. It is practicable to provide an adhesive layer (not shown in the figure) between the reinforcing plate 105 and the second isolation layer 103, and to bond the reinforcing plate 105 and the second isolation layer 103 together by using the adhesive layer.

[0125] like Fig.10 As shown, when a plurality of second slots 1002 are provided on the second isolation layer 103, the reinforcing plate 105 is provided above the first isolation layer 101. It is practicable to provide an adhesive layer (not shown in the figure) between the reinforcing plate 105 and the first isolation layer 101, and to bond the reinforcing plate 105 and the first isolation layer 101 together by using the adhesive layer.

[0126] When the deformable structure 1022 is a plastic structure, when the FPC 10 and the PCB 20 are assembled, the deformable structure 1022 is deformed under the action of an external force. After the external force is removed, the deformable structure 1022 will not exert force on the PCB 20. Therefore, there is no need to set a reinforcing plate 105.

[0127] Next, the FPC 10 having double-sided conductive layers is introduced in detail.

[0128] Fig.11 For along Figure 6 Another cross-sectional view of the flexible circuit board 10 of BB' shown in FIG. Fig.12 This is another cross-sectional view of the FPC 10 when the second slot 1002 is disposed in the second isolation layer 103 .

[0129] Compared with the FPC 10 with a single-sided conductive layer, the FPC 10 with a double-sided conductive layer further includes: a second conductive layer 106 and a third isolation layer 107. In the case where a plurality of second slots 1002 are provided on the first isolation layer 101, the second conductive layer 106 is provided below the second isolation layer 103, the third isolation layer 107 is provided below the second conductive layer 106, and at least one protruding structure 1061 is provided on the upper surface of the second conductive layer 106, and the protruding structure 1061 contacts the lower surface of the first conductive layer 102; in the case where a plurality of second slots 1002 are provided on the second isolation layer 103, the second conductive layer 106 is provided above the first isolation layer 101, the third isolation layer 107 is provided above the second conductive layer 106, and at least one protruding structure 1061 is provided on the lower surface of the second conductive layer 106, and the protruding structure 1061 contacts the upper surface of the first conductive layer 102.

[0130] The FPC 10 with double-sided conductive layers includes not only the first conductive layer 102 but also the second conductive layer 106 contacting the first conductive layer 102 through the protruding structure 1061 . The design of the double-sided conductive layer can greatly reduce the surface area of ​​the FPC 10 .

[0131] Specifically, if Fig.11 As shown, when a plurality of second slots 1002 are provided on the first isolation layer 101, the FPC 10 includes a first isolation layer 101, a first conductive layer 102, a second isolation layer 103, a second conductive layer 106 and a third isolation layer 107 stacked sequentially from top to bottom.

[0132] The first conductive layer 102 includes a first portion 1021 provided with a plurality of first grooves 1001, and a second portion including a plurality of deformable structures 1022, wherein the plurality of deformable structures 1022 correspond one-to-one to the plurality of first grooves 1001, and the plurality of deformable structures 1022 correspond one-to-one to the plurality of second grooves 1002 on the first isolation layer 101 or the second isolation layer 103. The deformable structure 1022 extends outward from the inside of the first groove 1001, passes through the second groove 1002 on the first isolation layer 101, and protrudes from the surface of the first isolation layer 101. Among them, at least one protruding structure 1061 is provided on the upper surface of the second conductive layer 106, and the protruding structure 1061 passes through the second isolation layer 103 and contacts with the lower surface of the first conductive layer 102, so as to realize the electrical connection between the second conductive layer 106 and the first conductive layer 102. In this way, after the FPC 10 and the PCB 20 are assembled, the electrical signals on the PCB 20 can be transmitted to the second conductive layer 106 through the plurality of deformable structures 1022 in contact with the PCB 20 .

[0133] It is feasible that an adhesive layer (not shown in the figure) can be provided between the second isolation layer 103 and the second conductive layer 106, and between the second conductive layer 106 and the third isolation layer 107, and the second isolation layer 103 and the second conductive layer 106 are bonded together, and the second conductive layer 106 and the third isolation layer 107 are bonded together by the adhesive layer.

[0134] like Fig.12 As shown, when a plurality of second slots 1002 are provided on the second isolation layer 103, the FPC 10 includes a third isolation layer 107, a second conductive layer 106, a first isolation layer 101, a first conductive layer 102 and a second isolation layer 103 stacked in sequence from top to bottom.

[0135] The first conductive layer 102 includes a first portion 1021 provided with a plurality of first grooves 1001, and a second portion including a plurality of deformable structures 1022, wherein the plurality of deformable structures 1022 correspond to the plurality of first grooves 1001 one by one, and the plurality of deformable structures 1022 correspond to the plurality of second grooves 1002 on the first isolation layer 101 or the second isolation layer 103 one by one. The deformable structures 1022 extend outward from the inside of the first grooves 1001, pass through the plurality of second grooves 1002 on the second isolation layer 103, and protrude from the surface of the second isolation layer 103. Among them, at least one protruding structure 1061 is provided on the lower surface of the second conductive layer 106, and the protruding structure 1061 passes through the first isolation layer 101 and contacts with the upper surface of the first conductive layer 102, so as to realize the electrical connection between the second conductive layer 106 and the first conductive layer 102. In this way, after the FPC 10 and the PCB 20 are assembled, the electrical signals on the PCB 20 can be transmitted to the second conductive layer 106 through the plurality of deformable structures 1022 and the protruding structures 1061 in contact with the PCB 20 .

[0136] It is feasible that an adhesive layer (not shown in the figure) can be provided between the first isolation layer 101 and the second conductive layer 106, and between the second conductive layer 106 and the third isolation layer 107, so as to bond the first isolation layer 101 and the second conductive layer 106 together, and to bond the second conductive layer 106 and the third isolation layer 107 together.

[0137] In the embodiment of the present application, if the elastic properties of the deformable structure 1022 are not considered, the first conductive layer 102 and the second conductive layer 106 can use the same high-conductivity material, such as copper, silver, etc. In this case, conductive patterns can be designed on both the first conductive layer 102 and the second conductive layer 106.

[0138] If the conductive performance of FPC10 is not considered, the first conductive layer 102 and the second conductive layer 106 can be made of the same high elastic material, such as beryllium copper alloy or titanium copper alloy. In this case, the first conductive layer 102 and the second conductive layer 106 can be provided with a deformable structure 1022. The implementation method of providing the deformable structure 1022 on the second conductive layer 106 can refer to the description of providing the deformable structure 1022 on the first conductive layer 102, and will not be repeated in this embodiment. It is worth mentioning that at this time, there is no need to design a conductive pattern on the FPC10, and the FPC10 can be used as an adapter board to achieve short-distance signal transmission. For example, the FPC10 can be used as an adapter board to connect the PCB20 with other flexible circuit boards with conductive patterns.

[0139] To take into account both the elasticity of the deformable structure 1022 and the conductivity of the FPC 10 , the elasticity of the first conductive layer 102 needs to be stronger than that of the second conductive layer 106 , and the conductivity of the second conductive layer 106 needs to be stronger than that of the first conductive layer 102 .

[0140] In this embodiment, the first conductive layer 102 is provided with better elasticity than the second conductive layer 106, so that the multiple deformable structures 1022 have good elasticity. After the FPC 10 and the PCB 20 are assembled, the deformable structure 1022 is deformed under the action of external force. After the external force is removed, the elastic force of the deformable structure 1022 will generate an action force on the PCB 20. Correspondingly, the PCB 20 will also generate a reaction force on the deformable structure 1022. There is an interaction force between the FPC 10 and the PCB 20, so that the contact between the FPC 10 and the PCB 20 is more compact and reliable. After the PCB 20 is removed, the deformable structure 1022 recovers its deformation, and the FPC 10 can be reused many times.

[0141] In this embodiment, the conductivity of the second conductive layer 106 is set to be stronger than that of the first conductive layer 102. The second conductive layer 106 can achieve good transmission of electrical signals. In this way, the first conductive layer 102 does not need to be designed with a conductive pattern, but a conductive pattern is designed on the second conductive layer 106 with better conductivity. The FPC 10 provided in the embodiment of the present application can take into account both the elasticity of the deformable structure 1022 and the conductivity of the FPC 10.

[0142] It should be noted that the stronger the elasticity of the metal, the higher its hardness, and the higher the hardness of the metal, the worse the conductivity; the lower the hardness of the metal, the better the conductivity. Therefore, the material of the first conductive layer 102 can be a material with a higher hardness such as beryllium copper alloy or titanium copper alloy, and the material of the second conductive layer 106 can be a material with a lower hardness such as copper or silver.

[0143] It is understandable that if Fig.13 and Fig.14 As shown, the FPC 10 with double-sided conductive layers in the embodiment of the present application may also include a first adhesive layer 104 and / or a reinforcing plate 105 .

[0144] The case where the FPC 10 with double-sided conductive layers includes the first adhesive layer 104 is substantially the same as the case where the FPC 10 with single-sided conductive layers includes the first adhesive layer 104 , and will not be described in detail in this embodiment.

[0145] The case where the FPC 10 with double-sided conductive layers includes the reinforcing plate 105 is substantially the same as the case where the FPC 10 with single-sided conductive layers includes the reinforcing plate 105, except that the position of the reinforcing plate 105 is different. Fig.13 As shown, in the case where a plurality of second slots 1002 are provided on the first isolation layer 101, the reinforcing plate 105 is provided below the third isolation layer 107; Fig.14As shown, when a plurality of second slots 1002 are provided on the second isolation layer 103 , the reinforcing plate 105 is provided above the third isolation layer 107 .

[0146] The materials of the specific film layer structure of the FPC 10 mentioned in the embodiment of the present application are introduced below.

[0147] The first isolation layer 101, the second isolation layer 103 and the third isolation layer 107 may be formed by a flexible substrate. The flexible substrate includes, but is not limited to, polyester (PET), polytetrafluoroethylene (PTFE), polyimide (PI), polycarbonate (PC), copolymer plastic (ABS), LCP (liquid crystal polymer), polyethylene naphthalate diformic acid glycol ester (PEN), polypropylene (PP), coated paper, woven fabric (including stretch woven fabric and non-stretch woven fabric), etc.

[0148] The first conductive layer 102 and the second conductive layer 106 can be formed of copper foil, aluminum foil, silver foil, gold foil, alloy materials and conductive paste. Alloy materials include but are not limited to copper alloys, silver alloys, etc., wherein the copper alloy is composed of copper and any one or more of beryllium, titanium, aluminum, nickel, zinc, manganese, tin, silicon, lead, etc. The conductive paste includes but is not limited to carbon-based conductive paste, metal particle conductive paste, inorganic conductive paste and other conductive pastes. Among them, the carbon-based conductive paste at least includes conductive carbon black or graphene, and the metal particle conductive paste at least includes conductive metal particles, such as copper, silver, gold, silver-coated copper, etc.

[0149] In the embodiment of the present application, the thickness of each film layer of the FPC 10 with double-sided conductive layers is illustrated as an example: it is assumed that the first covering layer is formed of crystal violet lactone (CVL) and its thickness is about 22.5 microns; the first conductive layer 102 is made of beryllium copper alloy and its thickness is about 38 microns; the second conductive layer 106 is made of copper and its thickness is about 12 microns; the second isolation layer 103 can be made of the same material as the first isolation layer 101. Since the second isolation layer 103 can be directly prepared and formed on the copper layer, its thickness is relatively small, about 15 microns; the third isolation layer 107 can be made of the same material as the first isolation layer 101, and its thickness can be the same as the first covering layer, about 22.5 microns; the reinforcing plate 105 is made of steel use stainless steel (SUS) and is bonded to the third isolation layer 107 through an AD adhesive layer, and the thickness of the AD adhesive layer is about 25 microns. Since the deformable structure 1022 on the first conductive layer 102 will deform when it contacts the PCB 20 and does not occupy the distance between the FPC 10 and the PCB 20, the total thickness of the FPC 10 with double-sided conductive layers in the embodiment of the present application may not include the height of the deformable structure 1022, and the total thickness of the FPC 10 is about 0.285 mm, which is less than 0.3 mm.

[0150] In the current method of connecting FPC10 and PCB20 through a board-to-board connector, a male or female head is installed on FPC10, and the thickness of FPC10 itself plus the thickness of the male or female head is greater than 0.6 mm; in the method of connecting FPC10 and PCB20 through a spring sheet, the thickness of FPC10 itself plus the thickness of the spring sheet is greater than 0.3 mm, while the total thickness of the new FPC10 provided in the embodiment of the present application is less than 0.3 mm. Therefore, after the FPC10 and PCB20 in the embodiment of the present application are assembled, the spacing distance between FPC10 and PCB20 is smaller, that is, the total thickness of FPC10 and PCB20 after assembly is smaller.

[0151] The following is combined with Figure 7 To Attachment Fig.14 The multiple deformable structures 1022 distributed on the first conductive layer 102 are introduced in detail.

[0152] In a possible implementation, the deformable structure 1022 is in a sheet shape. Thus, after the FPC 10 and the PCB 20 are assembled, the contact area between the sheet-shaped deformable structure 1022 and the PCB 20 is larger, which can reduce the contact resistance between the FPC 10 and the PCB 20 .

[0153] In one possible implementation, the deformable structure 1022 includes an inclined portion 10220 and a flat portion 10221, one end of the inclined portion 10220 is connected to the interior of the first groove 1001, and the other end is connected to the flat portion 10221, there is an angle less than 90 degrees between the inclined portion 10220 and the first portion 1021, and the flat portion 10221 is parallel to the first portion 1021.

[0154] Specifically, the first conductive layer 102 includes a first portion 1021 having a plurality of first slots 1001, and a second portion including a plurality of deformable structures 1022, wherein the deformable structures 1022 extend outward from the inside of the first slots 1001. The first portion 1021 is located between the first isolation layer 101 and the second isolation layer 103, and is arranged parallel to the first isolation layer 101 or the second isolation layer 103. A conductive pattern may be arranged in the area of ​​the first portion 1021 where the first slots 1001 are not arranged.

[0155] The plurality of deformable structures 1022 are not mounted on the FPC 10 but are part of the first conductive layer 102. The deformable structures 1022 specifically include an inclined portion 10220 and a flat portion 10221.

[0156] When a plurality of second slots 1002 are provided on the first isolation layer 101, one end of the inclined portion 10220 is connected to the inside of the first slot 1001, that is, the inclined portion 10220 extends from the surface of the first portion 1021 surrounding the first slot 1001 and is inclined toward the first isolation layer 101, and an angle less than 90 degrees exists between the inclined portion 10220 and the first portion 1021. The other end of the inclined portion 10220 is connected to one end of the flat portion 10221, and the other end of the flat portion 10221 is suspended, and the flat portion 10221 is parallel to the first portion 1021.

[0157] When a plurality of second slots 1002 are provided on the second isolation layer 103, one end of the inclined portion 10220 is connected to the inside of the first slot 1001, that is, the inclined portion 10220 extends from the surface of the first portion 1021 surrounding the first slot 1001 and is inclined toward the second isolation layer 103, and an angle less than 90 degrees exists between the inclined portion 10220 and the first portion 1021. The other end of the inclined portion 10220 is connected to one end of the flat portion 10221, and the other end of the flat portion 10221 is suspended, and the flat portion 10221 is parallel to the first portion 1021.

[0158] Since the flattened portion 10221 of the deformable structure 1022 is parallel to the first portion 1021 of the first conductive layer 102, and when the FPC 10 is assembled with the PCB 20, the PCB 20 is parallel to the first portion 1021 of the first conductive layer 102 in the FPC 10, the PCB 20 is also parallel to the flattened portion 10221 of the deformable structure 1022. In this way, after the FPC 10 is assembled with the PCB 20, the flattened portion 10221 of the deformable structure 1022 can contact the PCB 20 to the greatest extent, so as to further reduce the contact resistance between the FPC 10 and the PCB 20.

[0159] In a possible implementation, a height h1 of the plurality of deformable structures 1022 protruding from the surface of the first isolation layer 101 or the second isolation layer 103 is greater than 0.

[0160] In this embodiment, the height of the multiple deformable structures 1022 protruding from the surface of the first isolation layer 101 or the second isolation layer 103 is h1, and the height h1 is the vertical distance between the highest point of the deformable structure 1022 protruding from the first isolation layer 101 and the upper surface of the first isolation layer 101; or the height h1 is the vertical distance between the lowest point of the deformable structure 1022 protruding from the second isolation layer 103 and the lower surface of the second isolation layer 103. If the deformable structure 1022 includes the tiled portion 10221 in the above implementation, the height h1 is the vertical distance between the upper surface of the tiled portion 10221 and the upper surface of the first isolation layer 101, or the height h1 is the vertical distance between the lower surface of the tiled portion 10221 and the lower surface of the second isolation layer 103.

[0161] After the FPC 10 and the PCB 20 are assembled, the PCB 20 is pressed against the first isolation layer 101 or the second isolation layer 103 provided with a plurality of second slots 1002. If the deformable structure 1022 of the FPC 10 is lower than the surface of the first isolation layer 101 or the second isolation layer 103, the deformable structure 1022 cannot contact the PCB 20, and an electrical connection cannot be achieved between the FPC 10 and the PCB 20. If the height h1 of the plurality of deformable structures 1022 protruding from the surface of the first isolation layer 101 or the second isolation layer 103 is equal to 0, at this time, the deformable structure 1022 just contacts the PCB 20. Due to dimensional errors or assembly errors, etc., the deformable structure 1022 of the FPC 10 and the PCB 20 are prone to poor contact or large contact resistance. Therefore, to ensure that the deformable structures 1022 of FPC10 are in good contact with PCB20 after FPC10 and PCB20 are assembled, the height h1 of the plurality of deformable structures 1022 protruding from the surface of the first isolation layer 101 or the second isolation layer 103 in this embodiment needs to be greater than 0.

[0162] It is practicable to set the height h1 of the plurality of deformable structures 1022 protruding from the surface of the first isolation layer 101 or the second isolation layer 103 to be between 0.5 mm and 1 mm, so that after the FPC 10 and the PCB 20 are assembled, the contact effect between the deformable structure 1022 of the FPC 10 and the PCB 20 is better. Specifically, in this embodiment, the height h1 of the plurality of deformable structures 1022 protruding from the surface of the first isolation layer 101 or the second isolation layer 103 can be 0.5 mm, 0.7 mm, 0.9 mm, 1 mm, etc., which can be set by the designer and is not specifically limited in this embodiment.

[0163] In this embodiment, the deformable structure 1022 may be a plastic structure or an elastic structure.

[0164] In the case where the deformable structure 1022 is a plastic structure, when the FPC 10 is assembled with the PCB 20, the deformable structure 1022 on the FPC 10 is deformed under the action of an external force, and after the PCB 20 is removed, the deformable structure 1022 cannot return to its original state, so the FPC 10 cannot be reused. The plastic structure can be made of a material with low hardness and good conductivity, such as silver, copper, etc.

[0165] In the case where the deformable structure 1022 is an elastic structure, when the FPC10 is assembled with the PCB20, the deformable structure 1022 on the FPC10 is deformed under the action of an external force. Under the action of the elastic force of the deformable structure 1022, the FPC10 will generate an action force on the PCB20. Correspondingly, the PCB20 will also generate a reaction force on the deformable structure 1022. There is an interaction force between the FPC10 and the PCB20. In this way, the contact between the FPC10 and the PCB20 is tighter and more reliable. After the PCB20 is removed, the deformable structure 1022 will restore its deformation, and the FPC10 can be reused. It is feasible that the elastic structure can be made of a material with a higher hardness, such as a copper alloy, a beryllium copper alloy or a titanium copper alloy.

[0166] It should be understood that the above examples are intended to help those skilled in the art understand the embodiments of the present application, rather than to limit the embodiments of the present application to the specific numerical values ​​or specific scenarios illustrated. Those skilled in the art can obviously make various equivalent modifications or changes based on the above examples, and such modifications or changes also fall within the scope of the embodiments of the present application.

[0167] In a second aspect, the present application also provides an electronic device, the three-dimensional structure diagram of the electronic device is shown in FIG. Figure 1 and Figure 3 , the three-dimensional structure diagram of the connection between the printed circuit board 20 and the flexible circuit board 10 in the electronic device is shown in Figure 2 and Figure 4 .

[0168] The electronic device in the embodiment of the present application includes a printed circuit board 20 and a flexible circuit board 10 in the first aspect and any possible implementation of the first aspect. The three-dimensional structural diagram of the flexible circuit board 10 is shown in FIG. Figure 6 .

[0169] Fig.15 This is a schematic diagram of the three-dimensional structure of the printed circuit board 20 of an embodiment of the present application. The surface of the printed circuit board 20 is provided with a plurality of pads 201 corresponding one-to-one to the plurality of deformable structures 1022. The flexible circuit board 10 and the printed circuit board 20 are stacked and pressed together. During the process of stacking and pressing together the flexible circuit board 10 and the printed circuit board 20, the plurality of pads 201 are electrically connected to the plurality of deformable structures 1022.

[0170] In a possible implementation, the flexible circuit board 10 and the printed circuit board 20 may be mechanically connected via a connector (not shown in the figure).

[0171] In the embodiment of the present application, the FPC 10 and the PCB 20 can be mechanically connected using a connector to avoid the situation where the deformable structure 1022 and the pad 201 cannot correspond to each other and cannot be electrically connected after the FPC 10 and the PCB 20 are relatively displaced.

[0172] In practice, the FPC 10 may be provided with a plurality of first through holes (not shown in the figure), and the PCB 20 may be provided with second through holes (not shown in the figure) corresponding to the plurality of first through holes one by one; the FPC 10 and the PCB 20 are mechanically connected by fixing members disposed in the first through holes and the second through holes. It should be noted that the through hole penetrates all the film layer structures of the FPC 10, and when the FPC 10 includes a reinforcing plate 105, the through hole also penetrates the reinforcing plate 105.

[0173] In a possible implementation, the printed circuit board 20 has a plurality of grooves 2001, and the plurality of pads 201 are arranged in the plurality of grooves 2001 in a one-to-one correspondence. Thus, after the FPC 10 and the PCB 20 are stacked and pressed together, the deformable structure 1022 on the FPC 10 will extend into the groove 2001 of the PCB 20 and contact the pads 201 in the groove 2001. Thus, compared with the spacing distance between the FPC and the PCB after the two are assembled without a groove, the spacing distance between the FPC and the PCB after the two are assembled in the present application is smaller, and the thickness of the electronic device in the direction perpendicular to the display screen is smaller, that is, the thickness of the electronic device can be further reduced.

[0174] The structure of the groove 2001 can be realized as follows: Fig.15 As shown, the groove 2001 can be a cylindrical groove 2001, of course, it can also be a rectangular parallelepiped, a cube, a hemispherical shape, etc. Fig.16 For along Fig.15 PCB cross-section view in the CC direction, Fig.17 FIG. 2 is a cross-sectional view of the printed circuit board 20 when the groove 2001 is hemispherical. Figures 15 to 17 The structure of the middle groove 2001 is only for convenience of illustration and is not intended to limit the structure of the groove 2001 in this embodiment.

[0175] In a possible implementation, the height of the plurality of deformable structures 1022 protruding from the surface of the first isolation layer 101 or the second isolation layer 103 is greater than or equal to the depth h2 of the groove 2001 .

[0176] In this embodiment, the depth h2 of the groove 2001 can be understood as the vertical distance between the surface of the printed circuit board 20 and the lowest point of the bottom of the groove 2001. Fig.16 and Fig.17 The height of the plurality of deformable structures 1022 protruding from the surface of the first isolation layer 101 or the second isolation layer 103 (as shown in the attached figure) Figures 7 to 14 The depth h1) shown is greater than or equal to the depth h2 of the groove 2001. In this way, after the flexible circuit board 10 and the printed circuit board 20 are stacked and pressed together, the deformable structure 1022 is fully extended into the groove 2001, and the deformable structure 1022 contacts the pad 201 and deforms, or the deformable structure 1022 just contacts the pad 201, ensuring that the deformable structure 1022 is in good contact with the pad 201 in the groove 2001.

[0177] It should be understood that the above examples are intended to help those skilled in the art understand the embodiments of the present application, rather than to limit the embodiments of the present application to the specific numerical values ​​or specific scenarios illustrated. Those skilled in the art can obviously make various equivalent modifications or changes based on the above examples, and such modifications or changes also fall within the scope of the embodiments of the present application.

[0178] In a third aspect, an embodiment of the present application further provides a method for preparing a flexible circuit board. The method for preparing a flexible circuit board in an embodiment of the present application is used to prepare the flexible circuit board in the first aspect or any possible implementation of the first aspect.

[0179] Preparation in the present application example Figure 7 The preparation method of the FPC with a single-sided conductive layer shown in Fig.18 As shown, including:

[0180] Step S10: providing a first isolation layer, wherein the first isolation layer has a plurality of second grooves.

[0181] Specifically, the film structure prepared in step S10 is as follows: Fig.19As shown in (1), in this embodiment, the first isolation layer 101 can be prepared in advance or prepared when preparing the flexible circuit board. The first isolation layer 101 can be prepared by using a flexible substrate, and the flexible substrate includes but is not limited to polyester (Polyethylene terephthalate, PET), polytetrafluoroethylene (Polytetrafluoroethylene, PTFE), polyimide (Polyimide, PI), polycarbonate (Polycarbonate, PC), copolymer plastic (Acrylonitrile Butadiene Styrene plastic, ABS), LCP (Liquid Crystal Polymer), polyethylene naphthalate diformic acid glycol ester (Polyethylene naphthalate twoformic acid glycol ester, PEN), polypropylene (Polypropylene, PP), coated paper, woven fabric (including elastic woven fabric and non-stretchable woven fabric), etc.

[0182] After providing the first isolation layer 101 , a plurality of second openings 1002 penetrating the first isolation layer 101 may be opened in the first isolation layer 101 by means of laser or die punching.

[0183] Step S11: transferring the first isolation layer onto the prefabricated first conductive layer.

[0184] Specifically, the film structure prepared in step S11 is as follows: Fig.19 As shown in (2), in this embodiment, the first isolation layer 101 is transferred to the prefabricated first conductive layer 102, and is pressed onto the first conductive layer 102 by fast pressing.

[0185] The first conductive layer 102 can be formed of copper foil, aluminum foil, silver foil, gold foil, alloy materials and conductive paste. Alloy materials include but are not limited to copper alloys, silver alloys, etc., wherein the copper alloy is composed of copper and any one or more of beryllium, titanium, aluminum, nickel, zinc, manganese, tin, silicon, lead, etc. The conductive paste includes but is not limited to carbon-based conductive paste, metal particle conductive paste, inorganic conductive paste and other conductive pastes. Among them, the carbon-based conductive paste at least includes conductive carbon black or graphene, and the metal particle conductive paste at least includes conductive metal particles, such as copper, silver, gold, silver-coated copper, etc.

[0186] Realistically, in order to make the deformable structure 1022 formed after the first conductive layer 102 is processed have better elasticity, the first conductive layer 102 can be made of a material with higher hardness such as copper alloy.

[0187] In a possible implementation, between step S10 and step S11, a step of forming an adhesive layer on the first isolation layer 101 is also included, and the first isolation layer 101 and the adhesive layer are transferred to the prefabricated first conductive layer 102, and the adhesive layer bonds the first isolation layer 101 and the first conductive layer 102 together.

[0188] Step S12: Processing the first conductive layer within the plurality of second grooves to form a plurality of deformable structures corresponding one-to-one to the plurality of second grooves, and a plurality of first grooves corresponding one-to-one to the plurality of deformable structures, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the first isolation layer.

[0189] In one possible implementation, see Fig. 20 Step S12 specifically includes the following steps:

[0190] Step S120: etching the first conductive layer in the second groove to form an intermediate structure, wherein an edge of the intermediate structure is not completely connected to the first conductive layer.

[0191] Specifically, the film structure prepared in step S120 is as follows: Fig.19 (3) As shown in FIG. 1 , in this embodiment, the first conductive layer 102 located in the second groove 1002 is etched so that part of the edge of the intermediate structure is connected to the first conductive layer 102, while the other part is not connected to the first conductive layer 102. In this way, it is convenient to lift up the intermediate structure in subsequent operations. Figure 6 The second slot 1002 may be in a rectangular parallelepiped shape. Of course, the second slot 1002 may also be in a cylindrical shape, a cube shape, etc. Taking the second slot 1002 in a rectangular parallelepiped shape as an example, the intermediate structure in the embodiment of the present application is described. Fig.21 The intermediate structure 1020 shown in the top view may be rectangular or Fig. 22 The intermediate structure 1020 may also be in a trapezoidal shape in the top view. Fig.21 and Fig. 22 The shape of the intermediate structure 1020 shown is only for illustration and is not intended to limit the shape of the intermediate structure 1020 in the embodiment of the present application.

[0192] Step S121: Use a mold to stamp the intermediate structure to form a plurality of deformable structures corresponding to the plurality of second grooves, and a plurality of first grooves corresponding to the plurality of deformable structures, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the first isolation layer.

[0193] Specifically, the film structure prepared in step S121 is as follows: Fig.19As shown in (4), in this embodiment, the mold has a plurality of grooves corresponding to the plurality of intermediate structures, and the plurality of intermediate structures are placed corresponding to the plurality of grooves on the mold, and the intermediate structures are pushed into the grooves using a tool such as a push pin to form a deformable structure 1022, and the empty portion on the first conductive layer 102 after the intermediate structure is shifted forms a first slot 1001, and the deformable structure 1022 extends outward from the first slot 1001. At this time, the first conductive layer 102 includes two parts, the first part 1021 is parallel to the first isolation layer 101 and includes a plurality of first slots 1001, and the second part includes a plurality of deformable structures 1022, and the plurality of deformable structures 1022 correspond to the plurality of first slots 1001 one by one.

[0194] The height of the multiple deformable structures 1022 protruding from the surface of the first isolation layer 101 is the depth of the groove on the mold. The height of the multiple deformable structures 1022 protruding from the surface of the first isolation layer 101 can be controlled by controlling the depth of the groove on the mold.

[0195] Step S13: transferring the first isolation layer and the processed first conductive layer to a prefabricated structure, wherein the prefabricated structure at least includes a second isolation layer, and the first conductive layer is located between the first isolation layer and the second isolation layer.

[0196] Specifically, the prefabricated structure in step S13 can be seen in Fig.19 (5) The film structure obtained in step S13 is as follows Fig.19 As shown in (6), the prefabricated structure includes at least a second isolation layer 103, and the second isolation layer 103 and the first isolation layer 101 can be made of the same material. For details, please refer to the description of the first isolation layer 101 in step S11, which will not be repeated here. In this embodiment, if the prefabricated structure only includes the second isolation layer 103, after the first isolation layer 101 and the processed first conductive layer 102 are transferred to the second isolation layer 103, an FPC with a single-sided conductive layer is formed.

[0197] In a possible implementation, the preparation in the embodiment of the present application Fig.11 The preparation method of the FPC with double-sided conductive layers shown in FIG. Fig.23 As shown, specifically including:

[0198] Step S10: providing a first isolation layer, wherein the first isolation layer has a plurality of second grooves. The film structure prepared in step S10 is as follows: Fig.24 (1) as shown.

[0199] Step S11: transferring the first isolation layer to the prefabricated first conductive layer. The film structure prepared in step S11 is as follows: Fig.24 (2) as shown.

[0200] Step S12: Processing the first conductive layer within the plurality of second grooves to form a plurality of deformable structures corresponding one-to-one to the plurality of second grooves, and a plurality of first grooves corresponding one-to-one to the plurality of deformable structures, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the first isolation layer.

[0201] Among them, etching Fig.24 (2) The film structure formed after the first conductive layer 102 is as follows Fig.24 As shown in (3), the film structure formed after the etching of the first conductive layer 102 is as follows: Fig.24 (4) as shown.

[0202] Step S131: transferring the first isolation layer and the processed first conductive layer to a prefabricated structure, wherein the prefabricated structure at least comprises a first adhesive layer, a second isolation layer and a second conductive layer which are stacked, and the first adhesive layer is in contact with the first conductive layer.

[0203] The prefabricated structure in step S131 is shown in Fig.24 (5) The film structure obtained in step S131 is as follows Fig.24 (6) as shown.

[0204] Step S14: opening a through hole on the second conductive layer that penetrates the second conductive layer, the second isolation layer and the first adhesive layer.

[0205] Specifically, the film structure prepared in step S14 is as follows: Fig.24 (7) A through hole 1004 is formed on the second conductive layer 106 by laser or other methods. The through hole 1004 penetrates the second conductive layer 106, the second isolation layer 103 and the first adhesive layer 104, and exposes the first conductive layer 102.

[0206] Step S15: forming a protruding structure in the through hole that contacts both the first conductive layer and the second conductive layer.

[0207] Specifically, the through hole 1004 may be filled with the same material as the second conductive layer 106 , so that the conductivity between the protruding structure 1061 formed in the through hole 1004 and the second conductive layer 106 is good.

[0208] Step S16: transferring all the prepared film layers onto the prefabricated third isolation layer.

[0209] Specifically, the film structure prepared in step S16 is as follows: Fig.24(8) is shown. The material and preparation method of the third isolation layer 107 are the same as those of the first isolation layer 101. For details, please refer to the description of the first isolation layer 101 in step S11, which will not be repeated here. In this embodiment, after all the prepared film layers are transferred to the prefabricated third isolation layer 107, an FPC10 with a double-sided conductive layer is formed. It should be noted that the prefabricated third isolation layer 107 also includes a glue layer, which bonds the third isolation layer 107 to the second conductive layer 106.

[0210] Among them, prefabricated structures are Fig.25 The steps shown in the figure are prepared, specifically comprising:

[0211] Step S20: providing a second conductive layer.

[0212] Specifically, the second conductive layer 106 can be prepared in advance or can be prepared when preparing the flexible circuit board. The material of the second conductive layer 106 and the first conductive layer 102 can be the same or different. For example, the second conductive layer 106 can be formed of copper foil, aluminum foil, silver foil, gold foil, alloy material and conductive paste. In practice, in order to make the second conductive layer 106 have better conductive properties, the first conductive layer 102 can be prepared and formed by using a highly conductive material such as copper or silver.

[0213] Step S21: forming a second isolation layer on the second conductive layer.

[0214] Specifically, the second isolation layer 103 and the first isolation layer 101 can be made of the same material. For details, please refer to the description of the first isolation layer 101 in step S11, which will not be repeated here.

[0215] Step S22: forming a first adhesive layer on the second isolation layer, wherein the first adhesive layer has third grooves corresponding to the plurality of deformable structures one by one.

[0216] Specifically, the first adhesive layer 104 can be formed on the second isolation layer 103 by a coating process, and then the third slots 1003 corresponding to the plurality of deformable structures 1022 can be formed on the first adhesive layer 104 by laser or die punching, so that the deformable structure 1022 can be prevented from being stuck by the first adhesive layer 104 and unable to contact the PCB. It should be noted that the shape of the third slot 1003 is the same as that of the second slot 1002, and the description of the second slot 1002 can be referred to, and will not be repeated here.

[0217] Preparation in the present application example Figure 8 The preparation method of the FPC with double-sided conductive layers shown in FIG. Fig.26 As shown, including:

[0218] Step S30: providing a second isolation layer, wherein the second isolation layer has a plurality of second grooves.

[0219] Specifically, in this embodiment, the second isolation layer 103 can be prepared in advance or can be prepared when preparing the flexible circuit board. The second isolation layer 103 can be formed by using a flexible substrate, and the flexible substrate includes but is not limited to polyester (Polyethylene terephthalate, PET), polytetrafluoroethylene (Polytetrafluoroethylene, PTFE), polyimide (Polyimide, PI), polycarbonate (Polycarbonate, PC), copolymer plastic (AcrylonitrileButadieneStyrene plastic, ABS), LCP (Liquid Crystal Polymer), polyethylene naphthalate diformic acid glycol ester (Polyethylene naphthalate diformic acid glycol ester, PEN), polypropylene (Polypropylene, PP), coated paper, woven fabric (including elastic woven fabric and non-stretchable woven fabric), etc.

[0220] After providing the second isolation layer 103 , a plurality of second openings 1002 penetrating the second isolation layer 103 may be opened in the second isolation layer 103 by means of laser or die punching.

[0221] Step S31: transferring the second isolation layer onto the prefabricated first conductive layer.

[0222] Specifically, in this embodiment, the second isolation layer 103 is transferred to the prefabricated first conductive layer 102 and pressed onto the first conductive layer 102 by means of rapid pressing.

[0223] The first conductive layer 102 can be formed of copper foil, aluminum foil, silver foil, gold foil, alloy materials and conductive paste. Alloy materials include but are not limited to copper alloys, silver alloys, etc., wherein the copper alloy is composed of copper and any one or more of beryllium, titanium, aluminum, nickel, zinc, manganese, tin, silicon, lead, etc. The conductive paste includes but is not limited to carbon-based conductive paste, metal particle conductive paste, inorganic conductive paste and other conductive pastes. Among them, the carbon-based conductive paste at least includes conductive carbon black or graphene, and the metal particle conductive paste at least includes conductive metal particles, such as copper, silver, gold, silver-coated copper, etc.

[0224] Realistically, in order to make the deformable structure 1022 formed after the first conductive layer 102 is processed have better elasticity, the first conductive layer 102 can be made of a material with higher hardness such as copper alloy.

[0225] In a possible implementation, between step S30 and step S31, a step of forming an adhesive layer on the first isolation layer 101 is also included, and the second isolation layer 103 and the adhesive layer are transferred to the prefabricated first conductive layer 102, and the adhesive layer bonds the second isolation layer 103 and the first conductive layer 102 together.

[0226] Step S32: Processing the first conductive layer within the plurality of second grooves to form a plurality of deformable structures corresponding one-to-one to the plurality of second grooves, and a plurality of first grooves corresponding one-to-one to the plurality of deformable structures, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the second isolation layer.

[0227] In one possible implementation, see Fig. 27 , step S32 specifically includes the following steps:

[0228] Step S320: etching the first conductive layer in the second groove to form an intermediate structure, wherein an edge of the intermediate structure is not completely connected to the first conductive layer.

[0229] In this embodiment, step S320 is substantially the same as the above step S120 and will not be described again to avoid repetition.

[0230] Step S321: Use a mold to stamp the intermediate structure to form a plurality of deformable structures corresponding to the plurality of second grooves, and a plurality of first grooves corresponding to the plurality of deformable structures, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the second isolation layer.

[0231] In this embodiment, step S321 is substantially the same as the above-mentioned step S121, except that in this embodiment, the deformable structure 1022 protrudes from the surface of the second isolation layer 103, while in the embodiment where step S121 is located, the deformable structure 1022 protrudes from the surface of the first isolation layer 101. To avoid repetition, they are not described again here.

[0232] Step S33: transferring the second isolation layer and the processed first conductive layer to the prefabricated structure, wherein the prefabricated structure at least includes the first isolation layer, and the first conductive layer is located between the first isolation layer and the second isolation layer.

[0233] Specifically, the prefabricated structure includes at least a first isolation layer 101, and the first isolation layer 101 and the second isolation layer 103 can be made of the same material. For details, please refer to the description of the first isolation layer 101 in step S31, which will not be repeated here. In this embodiment, if the prefabricated structure only includes the first isolation layer 101, after the second isolation layer 103 and the processed first conductive layer 102 are transferred to the first isolation layer 101, an FPC with a single-sided conductive layer is formed.

[0234] In a possible implementation, the preparation in the embodiment of the present application Fig.12 The preparation method of the FPC with double-sided conductive layers shown in FIG. Fig.28 As shown, specifically including:

[0235] Step S30: providing a second isolation layer, wherein the second isolation layer has a plurality of second grooves.

[0236] Step S31: transferring the second isolation layer onto the prefabricated first conductive layer.

[0237] Step S32: Processing the first conductive layer within the plurality of second grooves to form a plurality of deformable structures corresponding one-to-one to the plurality of second grooves, and a plurality of first grooves corresponding one-to-one to the plurality of deformable structures, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the second isolation layer.

[0238] Step S331: transferring the second isolation layer and the processed first conductive layer to a prefabricated structure, wherein the prefabricated structure at least comprises a first adhesive layer, a first isolation layer and a second conductive layer which are stacked, and the first adhesive layer is in contact with the first conductive layer.

[0239] Step S34: opening a through hole on the second conductive layer that penetrates the second conductive layer, the first isolation layer, and the first adhesive layer.

[0240] Step S35: forming a protruding structure in the through hole that contacts both the first conductive layer and the second conductive layer.

[0241] Step S36: transferring all prepared film layers onto the prefabricated third isolation layer.

[0242] Specifically, steps S34 to S36 in this embodiment are substantially the same as steps S14 to S16 described above, except that the prefabricated structure in this embodiment includes the first isolation layer 101, while the prefabricated structure in the above content includes the second isolation layer 103. It should be noted that the prefabricated third isolation layer 107 also includes an adhesive layer, which bonds the third isolation layer 107 to the second conductive layer 106.

[0243] Among them, prefabricated structures are Fig.29 The steps shown in the figure are prepared, specifically comprising:

[0244] Step S40: providing a second conductive layer.

[0245] Step S41: forming a first isolation layer on the second conductive layer.

[0246] Step S42: forming a first adhesive layer on the first isolation layer, wherein the first adhesive layer has third grooves corresponding to the plurality of deformable structures one by one.

[0247] Specifically, steps S40 to S42 in this embodiment are substantially the same as steps S20 to S22 described above, with the difference being that the prefabricated structure in this embodiment includes a first isolation layer 101 , while the prefabricated structure in the above content includes a second isolation layer 103 .

[0248] It should be understood that the above examples are intended to help those skilled in the art understand the embodiments of the present application, rather than to limit the embodiments of the present application to the specific numerical values ​​or specific scenarios illustrated. Those skilled in the art can obviously make various equivalent modifications or changes based on the above examples, and such modifications or changes also fall within the scope of the embodiments of the present application.

[0249] It should be understood that the above is only to help those skilled in the art to better understand the embodiments of the present application, rather than to limit the scope of the embodiments of the present application. According to the above examples given, those skilled in the art can obviously make various equivalent modifications or changes. For example, some steps in each embodiment of the above detection method may be unnecessary, or some steps may be newly added. Or a combination of any two or any multiple embodiments of the above. Such modifications, changes or combined schemes also fall within the scope of the embodiments of the present application.

[0250] It should also be understood that the above description of the embodiments of the present application focuses on emphasizing the differences between the various embodiments. The same or similar points that are not mentioned can be referenced to each other. For the sake of brevity, they will not be repeated here.

[0251] It should also be understood that the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0252] It should also be understood that in the embodiments of the present application, "pre-setting" and "pre-definition" can be achieved by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in a device (for example, including an electronic device), and the present application does not limit its specific implementation method.

[0253] It should also be understood that the division of the methods, situations, categories and embodiments in the embodiments of the present application is only for the convenience of description and should not constitute a special limitation. The features of various methods, categories, situations and embodiments can be combined without contradiction.

[0254] It should also be understood that in the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0255] Finally, it should be noted that the above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A flexible circuit board, characterized in that: The flexible circuit board comprises: a first isolation layer, a first conductive layer and a second isolation layer stacked from top to bottom; The first conductive layer includes a first portion and a second portion, the first portion is provided with a plurality of first slots, the second portion includes a plurality of deformable structures, the plurality of deformable structures correspond to the plurality of first slots one by one, and the deformable structures extend outward from the inside of the first slots; A plurality of second grooves corresponding to the plurality of deformable structures are disposed on the first isolation layer or the second isolation layer, and the plurality of deformable structures pass through the plurality of second grooves and protrude from the surface of the first isolation layer or the second isolation layer.

2. The flexible circuit board according to claim 1, characterized in that: The deformable structure is in sheet shape.

3. The flexible circuit board according to claim 1 or 2, characterized in that: The deformable structure includes an inclined portion and a flat portion, one end of the inclined portion is connected to the interior of the first groove, and the other end is connected to the flat portion, an angle less than 90 degrees exists between the inclined portion and the first portion, and the flat portion is parallel to the first portion.

4. The flexible circuit board according to any one of claims 1 to 3, characterized in that: A height of the plurality of deformable structures protruding from a surface of the first isolation layer or the second isolation layer is greater than 0.

5. The flexible circuit board according to any one of claims 1 to 4, characterized in that: The flexible circuit board further comprises: a first adhesive layer, on which a plurality of third slots corresponding to the plurality of deformable structures are disposed; In the case where the plurality of second slots are provided on the first isolation layer, the first adhesive layer is located between the first conductive layer and the second isolation layer; When the second isolation layer is provided with the plurality of second grooves, the first adhesive layer is located between the first conductive layer and the first isolation layer.

6. The flexible circuit board according to any one of claims 1 to 5, characterized in that: The flexible circuit board also includes: a second conductive layer and a third isolation layer; In the case where the plurality of second grooves are provided on the first isolation layer, the second conductive layer is provided below the second isolation layer, the third isolation layer is provided below the second conductive layer, and at least one protruding structure is provided on the upper surface of the second conductive layer, and the protruding structure is in contact with the lower surface of the first conductive layer; When the second isolation layer is provided with the plurality of second grooves, the second conductive layer is provided above the first isolation layer, the third isolation layer is provided above the second conductive layer, and the lower surface of the second conductive layer is provided with at least one protruding structure, and the protruding structure is in contact with the upper surface of the first conductive layer.

7. The flexible circuit board according to claim 6, characterized in that: The elasticity of the first conductive layer is stronger than that of the second conductive layer, and the conductivity of the second conductive layer is stronger than that of the first conductive layer.

8. The flexible circuit board according to claim 7, characterized in that: The material of the first conductive layer is copper alloy, and the material of the second conductive layer is copper.

9. The flexible circuit board according to any one of claims 1 to 6, characterized in that: The deformable structure is an elastic structure.

10. The flexible circuit board according to any one of claims 7 to 9, characterized in that: The flexible circuit board further comprises: a reinforcing plate, wherein the reinforcing plate completely covers the area of ​​the first conductive layer where the deformable structure is distributed; In the case where the plurality of second slots are provided on the first isolation layer, the reinforcing plate is provided below the isolation layer farthest from the first isolation layer; When the second isolation layer is provided with the plurality of second grooves, the reinforcing plate is disposed above the isolation layer farthest from the second isolation layer.

11. The flexible circuit board according to any one of claims 1 to 6, characterized in that: The material of the first conductive layer is copper.

12. An electronic device, characterized in that: The electronic device comprises a printed circuit board and a flexible circuit board as described in any one of claims 1 to 11 above; The surface of the printed circuit board is provided with a plurality of solder pads corresponding one-to-one to the plurality of deformable structures, and the flexible circuit board is stacked and pressed tightly together with the printed circuit board. During the process of stacking and pressing together the flexible circuit board and the printed circuit board, the plurality of solder pads are electrically connected to the plurality of deformable structures.

13. The electronic device according to claim 12, characterized in that: The printed circuit board is provided with a plurality of grooves, and the plurality of pads are arranged in the plurality of grooves in a one-to-one correspondence.

14. The electronic device according to claim 13, characterized in that: A height of the plurality of deformable structures protruding from a surface of the first isolation layer or the second isolation layer is greater than or equal to a depth of the groove.

15. A method for preparing a flexible circuit board, characterized in that: include: Providing a first isolation layer, wherein the first isolation layer has a plurality of second grooves; transferring the first isolation layer onto the prefabricated first conductive layer; Processing the first conductive layer located in the plurality of second grooves to form a plurality of deformable structures corresponding to the plurality of second grooves one by one, and a plurality of first grooves corresponding to the plurality of deformable structures one by one, wherein the deformable structures extend outward from the inside of the first grooves, pass through the second grooves and protrude from the surface of the first isolation layer; transferring the first insulating layer and the processed first conductive layer to a prefabricated structure, wherein the prefabricated structure comprises at least a second insulating layer, and the first conductive layer is located between the first insulating layer and the second insulating layer; or, Providing a second isolation layer, wherein the second isolation layer has a plurality of second grooves; transferring the second isolation layer onto the prefabricated first conductive layer; Processing the first conductive layer located in the plurality of second grooves to form a plurality of deformable structures corresponding to the plurality of second grooves one by one, and a plurality of first grooves corresponding to the plurality of deformable structures one by one, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the second isolation layer; The second isolation layer and the processed first conductive layer are transferred to a prefabricated structure, wherein the prefabricated structure at least includes a first isolation layer, and the first conductive layer is located between the first isolation layer and the second isolation layer.

16. The method for preparing a flexible circuit board according to claim 15, characterized in that: The first conductive layer located in the plurality of second grooves is processed to form a plurality of deformable structures corresponding to the plurality of second grooves one by one, and a plurality of first grooves corresponding to the plurality of deformable structures one by one, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the first isolation layer, comprising: etching the first conductive layer in the second groove to form an intermediate structure, wherein an edge of the intermediate structure is not completely connected to the first conductive layer; Using a mold to punch the intermediate structure to form a plurality of deformable structures corresponding to the plurality of second grooves one by one, and a plurality of first grooves corresponding to the plurality of deformable structures one by one, wherein the deformable structures extend outward from the inside of the first grooves, pass through the second grooves and protrude from the surface of the first isolation layer; or, The first conductive layer located in the plurality of second grooves is processed to form a plurality of deformable structures corresponding to the plurality of second grooves one by one, and a plurality of first grooves corresponding to the plurality of deformable structures one by one, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the second isolation layer, comprising: etching the first conductive layer in the second groove to form an intermediate structure, wherein an edge of the intermediate structure is not completely connected to the first conductive layer; The intermediate structure is punched by a mold to form a plurality of deformable structures corresponding one-to-one to the plurality of second grooves, and a plurality of first grooves corresponding one-to-one to the plurality of deformable structures, wherein the deformable structure extends outward from the inside of the first groove, passes through the second groove and protrudes from the surface of the second isolation layer.

17. The method for preparing a flexible circuit board according to claim 15, characterized in that: In the case where the prefabricated structure comprises at least a second isolation layer, the prefabricated structure is prepared by the following steps: providing a second conductive layer; forming the second isolation layer on the second conductive layer; forming a first adhesive layer on the second isolation layer, wherein the first adhesive layer has third grooves corresponding to the plurality of deformable structures one by one; After transferring the first isolation layer and the processed first conductive layer to the prefabricated structure, the method further includes: A through hole is formed on the second conductive layer, penetrating the second conductive layer, the second isolation layer and the first adhesive layer; forming a protruding structure in the through hole, the protruding structure being in contact with both the first conductive layer and the second conductive layer; transferring all the prepared film layers onto the prefabricated third isolation layer, wherein the second conductive layer is in contact with the third isolation layer; or, In the case where the prefabricated structure comprises at least a first isolation layer, the prefabricated structure is prepared by the following steps: providing a second conductive layer; forming the first isolation layer on the second conductive layer; forming a first adhesive layer on the first isolation layer, wherein the first adhesive layer has third grooves corresponding to the plurality of deformable structures one by one; After transferring the second isolation layer and the processed first conductive layer to the prefabricated structure, the method further comprises: A through hole is formed on the second conductive layer, penetrating the second conductive layer, the first isolation layer and the first adhesive layer; forming a protruding structure in the through hole, the protruding structure being in contact with both the first conductive layer and the second conductive layer; All the prepared film layers are transferred onto the prefabricated third isolation layer, and the second conductive layer is in contact with the third isolation layer.

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