WO2023045640A1 - 柔性电路板、电路板组件以及电子设备 - Google Patents

柔性电路板、电路板组件以及电子设备 Download PDF

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Publication number
WO2023045640A1
WO2023045640A1 PCT/CN2022/113314 CN2022113314W WO2023045640A1 WO 2023045640 A1 WO2023045640 A1 WO 2023045640A1 CN 2022113314 W CN2022113314 W CN 2022113314W WO 2023045640 A1 WO2023045640 A1 WO 2023045640A1
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WO
WIPO (PCT)
Prior art keywords
hole
circuit board
metal layer
outer auxiliary
intersection point
Prior art date
Application number
PCT/CN2022/113314
Other languages
English (en)
French (fr)
Inventor
郭健强
罗文君
李明川
Original Assignee
荣耀终端有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 荣耀终端有限公司 filed Critical 荣耀终端有限公司
Priority to US18/000,891 priority Critical patent/US20240306300A1/en
Publication of WO2023045640A1 publication Critical patent/WO2023045640A1/zh

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/11—Printed elements for providing electric connections to or between printed circuits
    • H05K1/118—Printed elements for providing electric connections to or between printed circuits specially for flexible printed circuits, e.g. using folded portions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R12/00—Structural associations of a plurality of mutually-insulated electrical connecting elements, specially adapted for printed circuits, e.g. printed circuit boards [PCB], flat or ribbon cables, or like generally planar structures, e.g. terminal strips, terminal blocks; Coupling devices specially adapted for printed circuits, flat or ribbon cables, or like generally planar structures; Terminals specially adapted for contact with, or insertion into, printed circuits, flat or ribbon cables, or like generally planar structures
    • H01R12/50—Fixed connections
    • H01R12/59—Fixed connections for flexible printed circuits, flat or ribbon cables or like structures
    • H01R12/62—Fixed connections for flexible printed circuits, flat or ribbon cables or like structures connecting to rigid printed circuits or like structures
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0277—Bendability or stretchability details
    • H05K1/028—Bending or folding regions of flexible printed circuits
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/11—Printed elements for providing electric connections to or between printed circuits
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/11—Printed elements for providing electric connections to or between printed circuits
    • H05K1/115—Via connections; Lands around holes or via connections
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/11—Printed elements for providing electric connections to or between printed circuits
    • H05K1/115—Via connections; Lands around holes or via connections
    • H05K1/116—Lands, clearance holes or other lay-out details concerning the surrounding of a via
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/14—Structural association of two or more printed circuits
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/09372—Pads and lands
    • H05K2201/09481—Via in pad; Pad over filled via
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/095—Conductive through-holes or vias
    • H05K2201/09572—Solder filled plated through-hole in the final product
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09818—Shape or layout details not covered by a single group of H05K2201/09009 - H05K2201/09809
    • H05K2201/09854—Hole or via having special cross-section, e.g. elliptical

Definitions

  • the embodiments of the present application relate to the technical field of terminals, and in particular to a flexible circuit board, a circuit board assembly, and an electronic device.
  • Electronic equipment is usually provided with a printed circuit board (Printed Circuit Board, PCB) and a flexible circuit board (Flexible Printed Circuit, FPC).
  • PCB printed circuit Board
  • FPC Flexible Printed Circuit
  • the printed circuit board and the flexible circuit board need to be attached to each other for electrical connection.
  • the printed circuit board and the flexible circuit board are connected through a board-to-board connector (board to board, BTB).
  • BTB board to board
  • the mutual connection between the printed circuit board and the flexible circuit board is realized through the mutual plugging of two board-to-board connectors.
  • the board-to-board connector needs to occupy a large installation space, which is not conducive to the miniaturization of electronic equipment.
  • the flexible circuit board and the printed circuit board are soldered and connected using the soft board-hard board interconnection (FPC on board, FOB) technology.
  • FPC on board, FOB soft board-hard board interconnection
  • Embodiments of the present application provide a flexible circuit board, a circuit board assembly, and an electronic device, which can reduce the occurrence of tearing of the flexible circuit board at a soldering point.
  • the first aspect of the present application provides a flexible circuit board.
  • the flexible circuit board at least includes a flexible dielectric layer and a first connecting metal layer.
  • the flexible dielectric layer includes through holes extending along the thickness direction of the flexible dielectric layer.
  • the through holes include middle base holes and outer auxiliary holes. More than two outer auxiliary holes are distributed along the circumferential direction of the middle basic hole.
  • the middle basic hole communicates with more than two outer auxiliary holes.
  • the first connecting metal layer is disposed on the inner wall of the through hole and connected with the flexible dielectric layer.
  • the first connection metal layer includes a middle channel extending in a thickness direction.
  • the flexible circuit board of the embodiment of the present application includes a flexible dielectric layer and a first connecting metal layer.
  • Through holes are arranged on the flexible dielectric layer.
  • the through holes include middle base holes and outer auxiliary holes.
  • the shape of the through hole is different from that of the circular hole because more than two outer auxiliary holes are distributed along the circumferential direction of the middle basic hole.
  • the contact area between the first connection metal layer and the flexible dielectric layer can be relatively increased in a limited area, which is beneficial to improve the first connection metal layer. layer and the bonding force between the flexible dielectric layer.
  • the bonding force between the first connecting metal layer and the flexible dielectric layer in the embodiment of the present application is greater than the bonding force between the first connecting metal layer and the flexible dielectric layer when the through hole is a circular hole, so that the flexible dielectric layer
  • the connection between the layers and the first connecting metal layer can carry higher tensile forces.
  • the flexible circuit board of the embodiment of the present application is connected to the printed circuit board, and when the flexible dielectric layer is subjected to tensile force during the assembly process, the flexible dielectric layer and the first connecting metal layer are not easy to separate, which is beneficial to reduce the flexibility. The possibility of a tearing condition where the dielectric layer and the first connecting metal layer become decoupled.
  • more than two outer auxiliary holes are evenly distributed, so as to ensure that the overall shape of the through hole is regular, which is conducive to improving the inner wall of the through hole and the first connecting metal layer.
  • the stress balance of the connection area between them ensures the stability of the connection between the inner wall of the through hole and the first connection metal layer.
  • the axis of the outer auxiliary hole and the axis of the middle basic hole are parallel to each other, so that the extension direction of the outer auxiliary hole and the middle basic hole is the same, which is easy to process and manufacture.
  • the middle basic hole and the outer auxiliary hole are circular holes, which are easy to process and manufacture by laser ablation or mechanical drilling, and reduce the difficulty of processing and manufacturing due to the irregular shape of the through hole itself Large, resulting in the possibility of low yield of the flexible dielectric layer.
  • intersections P1 , P2 , P3 and P4 are formed by intersections between the orthographic projections of the outer auxiliary holes and the middle basic holes.
  • the axis of the intermediate foundation hole is located inside the area defined by the line connecting the intersection point P1, the intersection point P2, the intersection point P3 and the intersection point P4.
  • the axis of the outer auxiliary hole is located outside the area defined by the line connecting the intersection point P1, the intersection point P2, the intersection point P3 and the intersection point P4.
  • the line connecting the intersection point P1 and the intersection point P3 and the line connecting the intersection point P2 and the intersection point P4 intersect and the included angle ranges from 15° to 135°.
  • the two outer auxiliary holes are respectively located on two sides of the middle basic hole.
  • the outer auxiliary hole communicates with the middle foundation hole.
  • the axes of the two outer auxiliary holes and the axis of the middle basic hole lie in the same plane.
  • four outer auxiliary holes are arranged around the axis of the middle basic hole.
  • the inner wall area of the through hole formed by the four outer auxiliary holes and one intermediate basic hole is relatively larger, thereby further increasing the contact area between the first connecting metal layer and the inner wall of the through hole, which is conducive to further improving the connection between the first connecting metal layer and the through hole.
  • the binding force of the inner wall of the hole is relatively larger.
  • intersections P1 , P2 and P3 are formed between the orthographic projections of the outer auxiliary holes and the orthographic projections of the middle basic holes.
  • the axis of the middle foundation hole is located inside the area defined by the line connecting the intersection point P1, the intersection point P2 and the intersection point P3.
  • the axis of the outer auxiliary hole is located outside the area defined by the line connecting the intersection point P1, the intersection point P2 and the intersection point P3.
  • the included angle between the line connecting the intersection point P1 and the intersection point P2 and the line connecting the intersection point P2 and the intersection point P3 ranges from 15° to 90°.
  • three outer auxiliary holes are arranged around the axis of the middle basic hole.
  • the diameter of the outer auxiliary hole is larger than the diameter of the middle basic hole.
  • the diameters of each of the outer auxiliary holes are equal.
  • the diameter of the outer auxiliary hole is 1.3 times the diameter of the middle base hole.
  • the diameter of the outer auxiliary hole is smaller than the diameter of the middle basic hole.
  • the diameters of each of the outer auxiliary holes are equal.
  • the diameter of the outer auxiliary hole is 0.8 times the diameter of the middle base hole.
  • the flexible circuit board further includes a second connecting metal layer and a third connecting metal layer.
  • the second connecting metal layer and the third connecting metal layer are respectively disposed on two sides of the flexible dielectric layer.
  • the second connecting metal layer and the third connecting metal layer are respectively connected to the first connecting metal layer.
  • the second connection metal layer includes a first through hole communicating with the middle channel.
  • the third connection metal layer includes a second via hole communicating with the middle channel.
  • the second connecting metal layer and the third connecting metal layer are respectively connected to the flexible dielectric layer, which is beneficial to further improving the bonding force between the flexible dielectric layer and the welding pin.
  • the flexible dielectric layer includes two insulating base layers.
  • the through hole runs through the two insulating base layers.
  • the flexible circuit board also includes a fourth connection metal layer.
  • the fourth connecting metal layer is connected to the first connecting metal layer, and the fourth connecting metal layer is arranged between two insulating base layers.
  • the second aspect of the embodiment of the present application provides a circuit board assembly.
  • the circuit board assembly includes at least a printed circuit board and a flexible circuit board.
  • a printed circuit board includes pads.
  • the flexible circuit board at least includes a flexible dielectric layer and a first connecting metal layer.
  • the flexible dielectric layer includes through holes extending along the thickness direction of the flexible dielectric layer.
  • the through holes include middle base holes and outer auxiliary holes. More than two outer auxiliary holes are distributed along the circumferential direction of the middle basic hole.
  • the middle basic hole communicates with more than two outer auxiliary holes.
  • the first connecting metal layer is disposed on the inner wall of the through hole and connected with the flexible dielectric layer.
  • the first connection metal layer includes a middle channel extending in a thickness direction. The welding pad and the first connecting metal layer are welded through solder joints, and a part of the solder joints is filled in the middle channel.
  • more than two outer auxiliary holes are evenly distributed, so as to ensure that the overall shape of the through hole is regular, which is conducive to improving the inner wall of the through hole and the first connecting metal layer.
  • the stress balance of the connection area between them ensures the stability of the connection between the inner wall of the through hole and the first connection metal layer.
  • the axis of the outer auxiliary hole and the axis of the middle basic hole are parallel to each other, so that the extension direction of the outer auxiliary hole and the middle basic hole is the same, which is easy to process and manufacture.
  • the middle basic hole and the outer auxiliary hole are circular holes, which are easy to process and manufacture by laser ablation or mechanical drilling, and reduce the difficulty of processing and manufacturing due to the irregular shape of the through hole itself Large, resulting in the possibility of low yield of the flexible dielectric layer.
  • intersections P1 , P2 , P3 and P4 are formed by intersections between the orthographic projections of the outer auxiliary holes and the middle basic holes.
  • the axis of the intermediate foundation hole is located inside the area defined by the line connecting the intersection point P1, the intersection point P2, the intersection point P3 and the intersection point P4.
  • the axis of the outer auxiliary hole is located outside the area defined by the line connecting the intersection point P1, the intersection point P2, the intersection point P3 and the intersection point P4.
  • the line connecting the intersection point P1 and the intersection point P3 and the line connecting the intersection point P2 and the intersection point P4 intersect and the included angle ranges from 15° to 135°.
  • the two outer auxiliary holes are respectively located on two sides of the middle basic hole.
  • the outer auxiliary hole communicates with the middle foundation hole.
  • the axes of the two outer auxiliary holes and the axis of the middle basic hole lie in the same plane.
  • four outer auxiliary holes are arranged around the axis of the middle basic hole.
  • the inner wall area of the through hole formed by the four outer auxiliary holes and one intermediate basic hole is relatively larger, thereby further increasing the contact area between the first connecting metal layer and the inner wall of the through hole, which is conducive to further improving the connection between the first connecting metal layer and the through hole.
  • the binding force of the inner wall of the hole is relatively larger.
  • intersections P1 , P2 and P3 are formed between the orthographic projections of the outer auxiliary holes and the orthographic projections of the middle basic holes.
  • the axis of the middle foundation hole is located inside the area defined by the line connecting the intersection point P1, the intersection point P2 and the intersection point P3.
  • the axis of the outer auxiliary hole is located outside the area defined by the line connecting the intersection point P1, the intersection point P2 and the intersection point P3.
  • the included angle between the line connecting the intersection point P1 and the intersection point P2 and the line connecting the intersection point P2 and the intersection point P3 ranges from 15° to 90°.
  • three outer auxiliary holes are arranged around the axis of the middle basic hole.
  • the diameter of the outer auxiliary hole is larger than the diameter of the middle basic hole.
  • the diameters of each of the outer auxiliary holes are equal.
  • the diameter of the outer auxiliary hole is 1.3 times the diameter of the middle base hole.
  • the diameter of the outer auxiliary hole is smaller than the diameter of the middle basic hole.
  • the diameters of each of the outer auxiliary holes are equal.
  • the diameter of the outer auxiliary hole is 0.8 times the diameter of the middle base hole.
  • the flexible circuit board further includes a second connecting metal layer and a third connecting metal layer.
  • the second connecting metal layer and the third connecting metal layer are respectively disposed on two sides of the flexible dielectric layer.
  • the second connecting metal layer and the third connecting metal layer are respectively connected to the first connecting metal layer.
  • the second connection metal layer includes a first through hole communicating with the middle channel.
  • the third connection metal layer includes a second via hole communicating with the middle channel.
  • the second connecting metal layer and the third connecting metal layer are respectively connected to the flexible dielectric layer, which is beneficial to further improving the bonding force between the flexible dielectric layer and the welding pin.
  • the flexible dielectric layer includes two insulating base layers.
  • the through hole runs through the two insulating base layers.
  • the flexible circuit board also includes a fourth connection metal layer.
  • the fourth connecting metal layer is connected to the first connecting metal layer, and the fourth connecting metal layer is arranged between two insulating base layers.
  • a third aspect of the embodiments of the present application provides an electronic device.
  • the electronic equipment includes at least the above-mentioned circuit board assembly.
  • the circuit board assembly includes at least a printed circuit board and a flexible circuit board.
  • a printed circuit board includes pads.
  • the flexible circuit board at least includes a flexible dielectric layer and a first connecting metal layer.
  • the flexible dielectric layer includes through holes extending along the thickness direction of the flexible dielectric layer.
  • the through holes include middle base holes and outer auxiliary holes. More than two outer auxiliary holes are distributed along the circumferential direction of the middle basic hole.
  • the middle basic hole communicates with more than two outer auxiliary holes.
  • the first connecting metal layer is disposed on the inner wall of the through hole and connected with the flexible dielectric layer.
  • the first connection metal layer includes a middle channel extending in a thickness direction. The welding pad and the first connecting metal layer are welded through solder joints, and a part of the solder joints is filled in the middle channel.
  • more than two outer auxiliary holes are evenly distributed, so as to ensure that the overall shape of the through hole is regular, which is conducive to improving the inner wall of the through hole and the first connecting metal layer.
  • the stress balance of the connection area between them ensures the stability of the connection between the inner wall of the through hole and the first connection metal layer.
  • the axis of the outer auxiliary hole and the axis of the middle basic hole are parallel to each other, so that the extension direction of the outer auxiliary hole and the middle basic hole is the same, which is easy to process and manufacture.
  • the middle basic hole and the outer auxiliary hole are circular holes, which are easy to process and manufacture by laser ablation or mechanical drilling, and reduce the difficulty of processing and manufacturing due to the irregular shape of the through hole itself Large, resulting in the possibility of low yield of the flexible dielectric layer.
  • intersections P1 , P2 , P3 and P4 are formed by intersections between the orthographic projections of the outer auxiliary holes and the middle basic holes.
  • the axis of the intermediate foundation hole is located inside the area defined by the line connecting the intersection point P1, the intersection point P2, the intersection point P3 and the intersection point P4.
  • the axis of the outer auxiliary hole is located outside the area defined by the line connecting the intersection point P1, the intersection point P2, the intersection point P3 and the intersection point P4.
  • the line connecting the intersection point P1 and the intersection point P3 and the line connecting the intersection point P2 and the intersection point P4 intersect and the included angle ranges from 15° to 135°.
  • the two outer auxiliary holes are respectively located on two sides of the middle basic hole.
  • the outer auxiliary hole communicates with the middle foundation hole.
  • the axes of the two outer auxiliary holes and the axis of the middle basic hole lie in the same plane.
  • four outer auxiliary holes are arranged around the axis of the middle basic hole.
  • the inner wall area of the through hole formed by the four outer auxiliary holes and one intermediate basic hole is relatively larger, thereby further increasing the contact area between the first connecting metal layer and the inner wall of the through hole, which is conducive to further improving the connection between the first connecting metal layer and the through hole.
  • the binding force of the inner wall of the hole is relatively larger.
  • intersections P1 , P2 and P3 are formed between the orthographic projections of the outer auxiliary holes and the orthographic projections of the middle basic holes.
  • the axis of the middle foundation hole is located inside the area defined by the line connecting the intersection point P1, the intersection point P2 and the intersection point P3.
  • the axis of the outer auxiliary hole is located outside the area defined by the line connecting the intersection point P1, the intersection point P2 and the intersection point P3.
  • the included angle between the line connecting the intersection point P1 and the intersection point P2 and the line connecting the intersection point P2 and the intersection point P3 ranges from 15° to 90°.
  • three outer auxiliary holes are arranged around the axis of the middle basic hole.
  • the diameter of the outer auxiliary hole is larger than the diameter of the middle basic hole.
  • the diameters of each of the outer auxiliary holes are equal.
  • the diameter of the outer auxiliary hole is 1.3 times the diameter of the middle base hole.
  • the diameter of the outer auxiliary hole is smaller than the diameter of the middle basic hole.
  • the diameters of each of the outer auxiliary holes are equal.
  • the diameter of the outer auxiliary hole is 0.8 times the diameter of the middle base hole.
  • the flexible circuit board further includes a second connecting metal layer and a third connecting metal layer.
  • the second connecting metal layer and the third connecting metal layer are respectively disposed on two sides of the flexible dielectric layer.
  • the second connecting metal layer and the third connecting metal layer are respectively connected to the first connecting metal layer.
  • the second connection metal layer includes a first through hole communicating with the middle channel.
  • the third connection metal layer includes a second via hole communicating with the middle channel.
  • the second connecting metal layer and the third connecting metal layer are respectively connected to the flexible dielectric layer, which is beneficial to further improving the bonding force between the flexible dielectric layer and the welding pin.
  • the flexible dielectric layer includes two insulating base layers.
  • the through hole runs through the two insulating base layers.
  • the flexible circuit board also includes a fourth connection metal layer.
  • the fourth connecting metal layer is connected to the first connecting metal layer, and the fourth connecting metal layer is arranged between two insulating base layers.
  • FIG. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
  • FIG. 2 is a schematic diagram of a partial exploded structure of an electronic device according to an embodiment of the present application
  • FIG. 3 is a schematic structural view of a printed circuit board according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a partial structure of a circuit board assembly in the related art
  • FIG. 5 is a partial cross-sectional structural schematic diagram of a flexible circuit board in the related art
  • Figure 6 is an enlarged view of A in Figure 4.
  • FIG. 7 is a partial cross-sectional structural schematic diagram of setting solder paste on a pad of a printed circuit board
  • Fig. 8 is a schematic diagram of the first state when the printed circuit board, solder paste and flexible circuit board are connected;
  • Fig. 9 is a schematic diagram of the second state when the printed circuit board, solder paste and flexible circuit board are connected;
  • Fig. 10 is a partial cross-sectional structural schematic diagram of the connection state of the printed circuit board and the flexible circuit board;
  • Fig. 11 is a schematic diagram of a state where the flexible dielectric layer and the welding pin are separated;
  • FIG. 12 is a schematic diagram of a partial structure of a flexible circuit board according to an embodiment of the present application.
  • Figure 13 is an enlarged view at B in Figure 12;
  • FIG. 14 is a schematic diagram of a partial structure of a flexible dielectric layer according to an embodiment of the present application.
  • Figure 15 is an enlarged view at C in Figure 14;
  • 16 is a schematic diagram of a partial structure of a flexible dielectric layer according to another embodiment of the present application.
  • Figure 17 is an enlarged view at D in Figure 16;
  • FIG. 18 is a schematic diagram of a partial structure of a flexible dielectric layer according to yet another embodiment of the present application.
  • FIG. 19 is a schematic diagram of a partial structure of a flexible dielectric layer according to yet another embodiment of the present application.
  • Figure 20 is an enlarged view at E in Figure 19;
  • Fig. 21 is a schematic diagram of a partial structure of a flexible dielectric layer according to yet another embodiment of the present application.
  • Fig. 22 is a schematic diagram of a partial structure of a flexible dielectric layer according to yet another embodiment of the present application.
  • Fig. 23 is a schematic diagram of a partial structure of a flexible dielectric layer according to another embodiment of the present application.
  • Fig. 24 is a schematic diagram of a partial structure of a flexible dielectric layer according to yet another embodiment of the present application.
  • Fig. 25 is a partial cross-sectional structural schematic diagram of a flexible circuit board according to an embodiment of the present application.
  • FIG. 26 is a partial cross-sectional structural schematic diagram of a flexible circuit board according to another embodiment of the present application.
  • Fig. 27 is a partial cross-sectional structural schematic diagram of the connection state between the flexible circuit board and the printed circuit board of the embodiment shown in Fig. 26;
  • Fig. 28 is a partial cross-sectional structural schematic diagram of a flexible circuit board in the related art.
  • FIG. 29 is a partial cross-sectional structural schematic diagram of a flexible circuit board according to an embodiment of the present application.
  • Fig. 30 is a schematic diagram showing the comparison of the hole wall area of the intermediate channel with different shapes.
  • soldering pins 4221, first connecting metal layer; 4221a, middle channel; 4222, second connecting metal layer; 4222a, first through hole; 4223, third connecting metal layer; 4223a, second through hole; 4224 , the fourth connection metal layer;
  • the electronic device 10 in the embodiment of the present application can be called user equipment (user equipment, UE), terminal (terminal), etc.
  • the electronic device 10 can be a tablet computer (portable android device, PAD), personal digital processing (personal digital assistant, PDA), handheld devices with wireless communication functions, computing devices, vehicle-mounted devices, wearable devices, virtual reality (virtual reality, VR) terminal equipment, augmented reality (augmented reality, AR) terminal equipment, industrial control (industrial control) ), wireless terminals in self driving, wireless terminals in remote medical, wireless terminals in smart grid, wireless terminals in transportation safety Mobile terminals or fixed terminals such as wireless terminals in a smart city and wireless terminals in a smart home.
  • the form of the terminal device is not specifically limited in the embodiment of the present application.
  • FIG. 1 schematically shows the structure of an electronic device 10 according to an embodiment.
  • the handheld device with the wireless communication function may be, for example, a mobile phone.
  • FIG. 2 schematically shows a partial exploded structure of an electronic device 10 according to an embodiment.
  • the electronic device 10 of the embodiment of the present application includes a display assembly 20 , a middle frame 30 , a circuit board assembly 40 and a rear case 50 .
  • the display unit 20 has a display area for displaying image information.
  • the display area of the display component 20 faces away from the middle frame 30 . In the power-on state, the display area can display corresponding image information.
  • the middle frame 30 is disposed between the display assembly 20 and the rear case 50 . It should be noted that the thickness direction of the electronic device 10 refers to the arrangement direction of the display assembly 20 and the rear case 50 .
  • the circuit board assembly 40 is disposed in the space formed between the middle frame 30 and the rear case 50 , and is located inside the display assembly 20 , so that the user cannot easily observe the circuit board assembly 40 outside the electronic device 10 .
  • the circuit board assembly 40 may be disposed on a surface of the middle frame 30 facing the rear case 50 .
  • the circuit board assembly 40 includes a printed circuit board 41 (Printed Circuit Board, PCB) and a flexible circuit board 42 (Flexible Printed Circuit, FPC).
  • PCB printed Circuit Board
  • FPC Flexible Printed Circuit
  • FIG. 3 schematically shows the structure of the printed circuit board 41 .
  • the printed circuit board 41 can be single-sided or double-sided.
  • Single-sided board means that one side of the printed circuit board 41 is provided with the electronic device 60 .
  • Double-sided board refers to that the printed circuit board 41 is provided with electronic devices 60 on both sides.
  • the printed circuit board 41 may be a radio frequency (radio frequency, RF) board or an application processor (application processor, AP) board.
  • the radio frequency board can be used to carry radio frequency integrated circuit (RFIC), radio frequency power amplifier (radio frequency power amplifier, RFPA) and wireless fidelity (wireless fidelity, WIFI) chips, etc., but is not limited to.
  • An application processor board can be used, for example but not limited to, to host system on chip (SOC) components, double data rate (double data rate, DDR) memory, main power management unit (PMU) and auxiliary power supply Management chips, etc.
  • SOC system on chip
  • DDR double data rate
  • PMU main
  • the flexible circuit board 42 is used to connect the functional modules and corresponding electronic devices 60 on the printed circuit board 41 .
  • the flexible circuit board 42 can connect the camera module and the graphic processing chip on the printed circuit board 41 .
  • the flexible circuit board 42 can connect the display component 20 and the display and operation chips on the printed circuit board 41 .
  • the flexible circuit board 42 and the printed circuit board 41 are directly connected to eliminate the use of board-to-board connectors.
  • the flexible circuit board 42 and the printed circuit board 41 are connected by soldering.
  • One side of the printed circuit board 41 is provided with a soldering area 41a.
  • a plurality of pads 411 are provided on the bonding region 41a.
  • Each pad 411 of the printed circuit board 41 is electrically connected to the electronic device 60 provided on the printed circuit board 41 through the metal wire 412 on the printed circuit board 41 .
  • the material of the metal wire 412 and the pad 411 may be, but not limited to, copper or copper alloy.
  • FIG. 4 schematically shows the structure of the circuit board assembly 40 .
  • FIG. 5 schematically shows a partial structure of the flexible circuit board 42 of an embodiment.
  • the flexible circuit board 42 includes a flexible dielectric layer 421 , soldering pins 422 and metal traces 423 .
  • the flexible dielectric layer 421 is a layer structure with insulation function.
  • the flexible dielectric layer 421 is used to maintain the insulation state between the metal traces 423 or between the soldering pins 422 .
  • the material of the flexible dielectric layer 421 includes but not limited to polyimide (Polyimide, PI), thermoplastic polyimide (Thermoplastic polyimide, TPI) or polyester (polyethylene terephthalate, PET).
  • the flexible dielectric layer 421 has good flexibility, so it can be bent when subjected to external force.
  • the thickness of the flexible dielectric layer 421 ranges from 0.05 mm to 0.5 mm, such as but not limited to 0.05 mm, 0.075 mm, 0.1 mm, 0.11 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm.
  • the soldering pins 422 and the metal traces 423 are disposed on the flexible dielectric layer 421 .
  • the flexible circuit board 42 includes a plurality of metal traces 423 and a plurality of soldering pins 422 .
  • the plurality of soldering pins 422 are usually concentrated in one area and the plurality of soldering pins 422 are arranged in multiple rows.
  • Different metal traces 423 are connected to corresponding solder pins 422 .
  • the flexible circuit board 42 is welded and connected to the corresponding pad 411 on the printed circuit board 41 through the welding pin 422 , so as to realize the conduction between the flexible circuit board 42 and the printed circuit board 41 .
  • the material of the welding pin 422 and the metal trace 423 may be, but not limited to, copper or copper alloy.
  • the flexible dielectric layer 421 of the flexible circuit board 42 is provided with a through hole 4211 , for example, the through hole 4211 may be a circular hole.
  • the flexible dielectric layer 421 includes two opposite surfaces, and the through hole 4211 runs through the two surfaces of the flexible dielectric layer 421 .
  • the through hole 4211 may be formed on the flexible dielectric layer 421 by means of laser ablation or mechanical drilling.
  • the number of through holes 4211 is equal to the number of soldering pins 422 . In each row of through holes 4211 , a predetermined distance L needs to be maintained between two adjacent through holes 4211 .
  • the solder pin 422 includes a first connection metal layer 4221 .
  • the first connecting metal layer 4221 is disposed on the inner wall of the through hole 4211 and connected to the flexible dielectric layer 421 .
  • the first connection metal layer 4221 is formed on the inner wall of the through hole 4211 of the flexible dielectric layer 421 by electroless plating.
  • the first connecting metal layer 4221 is connected to the flexible dielectric layer 421 and has a predetermined bonding force therebetween. It should be noted that the bonding force refers to the force that needs to be overcome when separating the first connecting metal layer 4221 from the flexible dielectric layer 421 .
  • the force required to separate the first connecting metal layer 4221 from the flexible dielectric layer 421 can be applied to the flexible dielectric layer 421 in a direction away from the first connecting metal layer 4221 along the radial direction of the through hole 4211 to make the first connection
  • the first connection metal layer 4221 includes a middle channel 4221 a extending along the thickness direction X of the flexible dielectric layer 421 .
  • the predetermined distance L between two adjacent through holes 4211 refers to the vertical distance between the axes of two adjacent through holes 4211 .
  • the shape of the middle channel 4221a is the same as that of the through hole 4211, that is, the middle channel 4221a may be a circular hole.
  • the maximum dimension of the cross-section of the intermediate channel 4221a is the diameter of the intermediate channel 4221a.
  • the diameter of the middle channel 4221a can be, but not limited to, 0.15 mm, 0.2 mm, 0.4
  • the flexible circuit board 42 also needs to be provided with the same number of soldering pins 422 .
  • One welding pin 422 is set corresponding to one pad 411 .
  • 30 pads 411 are set on the printed circuit board 41
  • 30 welding pins 422 also need to be set on the flexible circuit board 42 .
  • the predetermined distance L between two adjacent through holes 4211 changes, the distance between two adjacent soldering pins 422 will also change, so that the soldering pins 422 on the flexible circuit board 42 cannot be in contact with the printed circuit board.
  • the pads 411 on the printed circuit board 41 are aligned.
  • connection force refers to the force that needs to be overcome when the welding pin 422 is separated from the pad 411 .
  • the force required to separate the welding pin 422 from the pad 411 may be along the axial direction of the through hole 4211, when the welding pin 422 is applied in a direction away from the pad 411 and the welding pin 422 is separated from the pad 411. required tensile stress.
  • each through hole 4211 is limited.
  • a corresponding number of limited areas 42a are divided on the flexible circuit board 42 , and each limited area 42a is correspondingly provided with a through hole 4211 .
  • solder paste 70 is pre-printed on the pad 411 on the printed circuit board 41 .
  • tin metal and flux may be included in the solder paste 70 .
  • the soldering pins 422 of the flexible circuit board 42 are in contact with the corresponding pads 411 of the printed circuit board 41 through the solder paste 70 .
  • FIG. 9 on the side of the flexible circuit board 42 facing away from the pad 411 , a compressive stress is applied to the area of the flexible circuit board 42 where the soldering pins 422 are placed toward the pad 411 .
  • the solder paste 70 between the solder pins 422 and the corresponding pads 411 is heated.
  • the solder paste 70 is heated using a laser.
  • the solder paste 70 melts after absorbing heat. Since the flexible circuit board 42 and the printed circuit board 41 can squeeze the melted solder paste 70 , part of the melted solder paste 70 will enter the middle channel 4221 a of the first connecting metal layer 4221 .
  • the solder paste 70 rises in the middle channel 4221 a of the first connecting metal layer 4221 . 10 after the solder paste 70 solidifies, the solder paste 70 forms a solder joint 80, so that the welding pin 422 of the flexible circuit board 42 is connected to the solder pad 411 of the corresponding printed circuit board 41 through the solder joint 80 and achieve conduction.
  • the solder paste 70 rises in the middle channel 4221 a of the first connecting metal layer 4221 and overflows from the opening of the middle channel 4221 a facing away from the pad 411 .
  • the overflowing solder paste 70 can cover the opening of the middle channel 4221 a facing away from the pad 411 .
  • the size of the pad 411 of the printed circuit board 41 is larger than the opening size of the middle channel 4221 a of the first connecting metal layer 4221 facing the pad 411 .
  • the solder paste 70 between the soldering pins 422 of the flexible circuit board 42 and the corresponding pads 411 of the printed circuit board 41 can cover the opening of the middle channel 4221 a facing the pads 411 .
  • a barrier 413 may be provided around the pad 411 of the printed circuit board 41 . The barrier portion 413 is used to prevent the melted solder paste 70 from flowing to areas other than the pad 411.
  • the flexible circuit board 42 is in contact with the blocking portion 413 , so that a gap is formed between the soldering pin 422 of the flexible circuit board 42 and the corresponding pad 411 of the printed circuit board 41 .
  • This gap can be used to accommodate the solder paste 70, thereby reducing the possibility that the melted solder paste 70 is extruded from between the soldering pin 422 and the corresponding pad 411, thereby reducing the The remaining amount of solder paste 70 between 411 is relatively small, which may lead to the possibility that the connection force between the soldering pin 422 and the corresponding pad 411 after soldering is relatively small.
  • FIG. 11 schematically shows the separation state of the flexible dielectric layer 421 and the first connection metal layer 4221 .
  • the flexible circuit board 42 of the embodiment of the present application can improve the bonding force between the flexible dielectric layer 421 and the first connecting metal layer 4221, so that the flexible dielectric layer 421 can bear a greater tensile force, which is beneficial to reduce the flexibility.
  • the dielectric layer 421 bears tensile force, resulting in the possibility of separation between the flexible dielectric layer 421 and the first connecting metal layer 4221 due to the disconnection state.
  • FIG. 12 schematically shows a partial structure of a flexible circuit board 42 according to an embodiment.
  • the flexible circuit board 42 includes a flexible dielectric layer 421 and a first connection metal layer 4221 .
  • the flexible dielectric layer 421 is connected to the first connecting metal layer 4221 .
  • the flexible dielectric layer 421 has a predetermined thickness.
  • the flexible dielectric layer 421 includes a through hole 4211 .
  • the flexible dielectric layer 421 has two opposite surfaces in its own thickness direction. One opening of the through hole 4211 is located on one surface of the flexible dielectric layer 421 , and the other opening is located on the other surface of the flexible dielectric layer 421 .
  • the through hole 4211 includes an outer auxiliary hole 4211a and a middle base hole 4211b. More than two outer auxiliary holes 4211a are distributed along the circumferential direction Y of the middle basic hole 4211b.
  • the middle basic hole 4211b communicates with two or more outer auxiliary holes 4211a.
  • the first connecting metal layer 4221 is disposed on the inner wall of the through hole 4211 and connected to the flexible dielectric layer 421 .
  • the contour of the outer peripheral surface of the first connection metal layer 4221 facing the inner wall of the through hole 4211 matches the contour of the inner wall of the through hole 4211 and maintains a contact state.
  • the first connection metal layer 4221 includes a middle channel 4221 a extending along the thickness direction X.
  • the circumferential direction Y of the intermediate basic hole 4211b refers to the direction around the axis of the intermediate basic hole 4211b.
  • the flexible circuit board 42 of the embodiment of the present application includes a flexible dielectric layer 421 and a first connecting metal layer 4221 .
  • a through hole 4211 is disposed on the flexible dielectric layer 421 .
  • the through hole 4211 includes an outer auxiliary hole 4211a and a middle base hole 4211b.
  • the shape of the through hole 4211 is different from that of the circular hole. The shapes are different.
  • the bonding force between the first connecting metal layer 4221 and the flexible dielectric layer 421 in the embodiment of the present application is greater than the bonding force between the first connecting metal layer 4221 and the flexible dielectric layer 421 when the through hole 4211 is a circular hole. , so that the joint between the flexible dielectric layer 421 and the first connecting metal layer can bear a larger tensile force.
  • the flexible circuit board 42 of the embodiment of the present application is connected to the printed circuit board 41, and when the flexible dielectric layer 421 is subjected to a tensile force during the assembly process, the flexible dielectric layer 421 and the first connecting metal layer 4221 are not easy to separate, Therefore, it is beneficial to reduce the possibility of the flexible dielectric layer 421 and the first connecting metal layer 4221 being disconnected and tearing.
  • the cross-sectional shape of the middle channel 4221 a of the first connecting metal layer 4221 is the same as the cross-sectional shape of the through hole 4211 .
  • the first connecting metal layer 4221 is evenly disposed on the inner wall of the through hole 4211 , so that along a direction perpendicular to the inner wall, the thickness of each position of the first connecting metal layer 4221 is equal.
  • FIG. 14 schematically shows a partial structure of a flexible dielectric layer 421 according to an embodiment.
  • the flexible circuit board 42 includes multiple rows of through holes 4211 .
  • the predetermined distance L between two adjacent through holes 4211 refers to the vertical distance between the axes bb of two adjacent intermediate basic holes 4211 b.
  • more than two outer auxiliary holes 4211a are evenly distributed along the circumferential direction Y of the middle basic hole 4211b, so as to ensure that the overall shape of the through hole 4211 is regular, which is conducive to improving the inner wall of the through hole 4211 and the first connecting metal.
  • the force balance of the connection area between the layers 4221 ensures the stability of the connection between the inner wall of the through hole 4211 and the first connection metal layer 4221 .
  • the axis aa of the outer auxiliary hole 4211a is spaced apart from the axis bb of the middle basic hole 4211b.
  • both the outer auxiliary hole 4211a and the middle basic hole 4211b are through holes.
  • the outer auxiliary hole 4211a and the middle basic hole 4211b are circular holes, which are easy to process and manufacture by laser ablation or mechanical drilling, and reduce the difficulty of processing and manufacturing due to the irregular shape of the through hole 4211 itself. , resulting in the possibility of low yield of the flexible dielectric layer 421 .
  • the two or more outer auxiliary holes 4211a are evenly distributed along the circumferential direction Y of the middle basic hole 4211b, the axes of the two or more outer auxiliary holes 4211a are located on the same circular trajectory. The axis of this circular locus coincides with the axis of the intermediate base hole 4211b.
  • the two outer auxiliary holes 4211a are distributed along the Y direction of the middle basic hole 4211b.
  • the processing process of the through hole 4211 may be to form a middle basic hole 4211b on the flexible dielectric layer 421 in advance, and then process and form an outer auxiliary hole 4211a based on the middle basic hole 4211b. Since there is an intersecting area between the outer auxiliary hole 4211a and the middle basic hole 4211b, when forming the outer auxiliary hole 4211a, at least part of the inner wall of the middle basic hole 4211b will be removed, so that when observing the processed through hole 4211, the middle basic hole 4211b and The respective inner walls of the outer auxiliary holes 4211a are disconnected and discontinuous at the line connecting the intersection points.
  • the two outer auxiliary holes 4211a are evenly distributed along the circumferential direction Y of the middle basic hole 4211b.
  • the middle base hole 4211b is located between the two outer auxiliary holes 4211a.
  • the respective axes of the two outer auxiliary holes 4211a and the middle basic hole 4211b are located in the same plane.
  • the arrangement direction of the two outer auxiliary holes 4211 a and the middle basic hole 4211 b may be perpendicular to the arrangement direction of each row of through holes 4211 .
  • intersections between the orthographic projections of the two outer auxiliary holes 4211a and the middle basic hole 4211b form intersections P1 , P2 , P3 and P4 .
  • the axis of the middle basic hole 4211b is located inside the area defined by the line connecting the intersection points P1, P2, P3, and P4, while the axis of the outer auxiliary hole 4211a is located on the line connecting the intersection points P1, P2, P3, and P4. outside the restricted area.
  • the area defined by the lines connecting the intersection point P1, the intersection point P2, the intersection point P3 and the intersection point P4 is a quadrilateral, such as a trapezoid or a rectangle.
  • intersection points between the orthographic projection of an outer auxiliary hole 4211a and the orthographic projection of the middle basic hole 4211b There are two intersection points between the orthographic projection of an outer auxiliary hole 4211a and the orthographic projection of the middle basic hole 4211b, which are intersection points P1 and intersection points P2 respectively.
  • intersection points between the orthographic projection of the other outer auxiliary hole 4211a and the orthographic projection of the middle basic hole 4211b which are the intersection point P3 and the intersection point P4 respectively.
  • the axis aa of an outer auxiliary hole 4211a and the axis bb of the middle basic hole 4211b are respectively located on both sides of the line connecting the intersection point P1 and the intersection point P2.
  • the axis aa of the other outer auxiliary hole 4211a and the axis bb of the middle basic hole 4211b are respectively located on both sides of the line connecting the intersection point P3 and the intersection point P4.
  • the length of the line connecting the intersection point P1 and the intersection point P2 may be smaller than the diameter of any one of the outer auxiliary hole 4211a and the middle foundation hole 4211b, and the length of the line connecting the intersection point P3 and the intersection point P4 may also be shorter than any of the outer auxiliary hole 4211a and the middle foundation hole 4211b.
  • the outer auxiliary hole 4211a communicates with the middle basic hole 4211b, the respective inner walls of the outer auxiliary hole 4211a and the middle basic hole 4211b are disconnected and discontinuous in the area between the intersection point P1 and the intersection point P2 and between the intersection point P3 and the intersection point P4.
  • the line connecting the intersection point P1 and the intersection point P3 and the line connecting the intersection point P2 and the intersection point P4 intersect and the included angle ⁇ ranges from 15° to 135°.
  • the line connecting the intersection point P1 and the intersection point P3 and the line connecting the intersection point P2 and the intersection point P4 intersect and the included angle ⁇ ranges from 30° to 90°.
  • the included angle ⁇ may be, but not limited to, 30°, 45°, 50°, 60°, 70°, 80°, 90°.
  • the diameters of the two outer auxiliary holes 4211 a are the same.
  • the diameter of the outer auxiliary hole 4211a is the same as that of the middle basic hole 4211b.
  • the through hole 4211 formed by the outer auxiliary hole 4211a and the middle basic hole 4211b is referred to as a first type hole.
  • the two outer auxiliary holes 4211a can be arranged symmetrically with respect to the axis of the middle basic hole 4211b, so as to facilitate the bonding force between the inner wall of one outer auxiliary hole 4211a and the first connecting metal layer 4221 and the inner wall of the other outer auxiliary hole 4211a to The bonding force between the first connecting metal layers 4221 is kept balanced.
  • the diameter of the middle basic hole 4211b may range from 0.05 mm to 0.5 mm, for example, but not limited to 0.12 mm.
  • the vertical distance between the axis aa of the outer auxiliary hole 4211a and the axis bb of the middle base hole 4211b is greater than the radius of the middle base hole 4211b.
  • the diameter of the outer auxiliary hole 4211a refers to the length of the line between K1 and K2.
  • the diameter of the intermediate basic hole 4211b refers to the length of the line between the intersection point P1 and the intersection point P3 or the length of the line between the intersection point P2 and the intersection point P4.
  • a part of the middle foundation hole 4211b is located on the side of the line connecting the intersection point P1 and the intersection point P4 away from the axis bb of the middle foundation hole 4211b, and a part of the middle foundation hole 4211b is located on the side of the line connecting the intersection point P2 and the intersection point P3 away from the middle foundation hole 4211b on one side of axis bb.
  • the through hole 4211 of the present application may be a straight hole.
  • the depth direction of the through hole 4211 is the same as the thickness direction X of the flexible dielectric layer 421 .
  • the through hole 4211 is a straight hole, which is also easy to be manufactured by laser ablation or mechanical drilling.
  • FIG. 16 schematically shows a partial structure of a flexible dielectric layer 421 according to an embodiment.
  • the same parts of the through hole 4211 in this embodiment and the through hole 4211 in the embodiment shown in FIG. 15 will not be repeated, and the differences will be mainly described here.
  • the diameters of the two outer auxiliary holes 4211a are both smaller than the diameter of the middle basic hole 4211b.
  • the through hole 4211 formed by the outer auxiliary hole 4211a and the middle basic hole 4211b in this embodiment is referred to as a second type hole.
  • the diameter of one outer auxiliary hole 4211a is smaller than 0.85 times the diameter of the middle basic hole 4211b, and the diameter of the other outer auxiliary hole 4211a is smaller than 1 times the diameter of the middle basic hole 4211b.
  • the diameters of the two outer auxiliary holes 4211a may be the same, for example, the diameters of the two outer auxiliary holes 4211a are equal to 0.8 times the diameter of the middle basic hole 4211b.
  • the diameter of the middle foundation hole 4211b ranges from 0.05mm to 0.5mm.
  • the diameter of the middle base hole 4211b may be, but not limited to, 0.12 mm.
  • the first connection metal layer 4221 is disposed within the through hole 4211 .
  • the cross-sectional shape of the middle channel 4221 a of the first connecting metal layer 4221 is the same as that of the through hole 4211 .
  • the first connecting metal layer 4221 is evenly disposed on the inner wall of the through hole 4211 , so that along a direction perpendicular to the inner wall, the thickness of each position of the first connecting metal layer 4221 is equal.
  • FIG. 18 schematically shows a partial structure of a flexible dielectric layer 421 according to an embodiment.
  • the same parts of the through hole 4211 in this embodiment and the through hole 4211 in the embodiment shown in FIG. 15 will not be repeated, and the differences will be mainly described here.
  • the diameters of the two outer auxiliary holes 4211a are larger than the diameter of the middle basic hole 4211b.
  • the through hole 4211 formed by the outer auxiliary hole 4211a and the middle basic hole 4211b in this embodiment is called a third type hole.
  • the diameter of one outer auxiliary hole 4211a is greater than 1.1 times the diameter of the middle basic hole 4211b, and the diameter of the other outer auxiliary hole 4211a is greater than or equal to 1 times the diameter of the middle basic hole 4211b.
  • the diameters of the two outer auxiliary holes 4211a are equal to 1.3 times the diameter of the middle basic hole 4211b.
  • FIG. 19 schematically shows a partial structure of a flexible dielectric layer 421 according to an embodiment.
  • both the outer auxiliary hole 4211a and the middle basic hole 4211b can be square holes.
  • the diameter of the outer auxiliary hole 4211a is smaller than that of the middle basic hole 4211b.
  • the number of outer auxiliary holes 4211a is two.
  • the axis aa of one outer auxiliary hole 4211a may intersect the line connecting the intersection points P1 and P2, while the axis aa of the other outer auxiliary hole 4211a may intersect the line connecting the intersection points P3 and P4.
  • the through hole 4211 formed by the outer auxiliary hole 4211a and the middle basic hole 4211b in this embodiment is called a fourth type hole.
  • the first connection metal layer 4221 is disposed within the through hole 4211 .
  • the cross-sectional shape of the middle channel 4221 a of the first connecting metal layer 4221 is the same as that of the through hole 4211 .
  • the first connecting metal layer 4221 is evenly disposed on the inner wall of the through hole 4211 , so that along a direction perpendicular to the inner wall, the thickness of each position of the first connecting metal layer 4221 is equal.
  • FIG. 21 schematically shows a partial structure of a flexible dielectric layer 421 according to an embodiment.
  • three outer auxiliary holes 4211a are distributed along the circumferential direction Y of the middle basic hole 4211b.
  • the through hole 4211 formed by the outer auxiliary hole 4211a and the middle basic hole 4211b in this embodiment is called a fifth type hole.
  • the area of the inner wall of the through hole 4211 formed by the three outer auxiliary holes 4211a and one intermediate basic hole 4211b is relatively larger, so that the contact area between the first connecting metal layer 4221 and the inner wall of the through hole 4211 can be increased.
  • Intersections P1 , P2 and P3 are formed between the orthographic projections of the outer auxiliary holes 4211 a and the middle basic holes 4211 b .
  • the axis of the middle basic hole 4211b is located inside the area defined by the line connecting the intersection points P1, P2, and P3, while the axis of the outer auxiliary hole 4211a is located outside the area defined by the line connecting the intersection points P1, P2, and P3.
  • the area defined by the line connecting the intersection point P1, the intersection point P2 and the intersection point P3 is triangular.
  • the angle ⁇ between the line connecting the intersection point P1 and the intersection point P2 and the line connecting the intersection point P2 and the intersection point P3 ranges from 15° to 90°.
  • the angle ⁇ may be, but not limited to, 30°, 45°, 50°, 60°, 70°, 80°, 90°.
  • the three outer auxiliary holes 4211a can be arranged tangentially, and the intersection points P1, P2 and P3 are the tangent points respectively.
  • the three outer auxiliary holes 4211a are evenly distributed along the circumferential direction Y of the middle basic hole 4211b, so that after the first connecting metal layer 4221 is connected to the inner wall of the through hole 4211, it is beneficial to ensure that the first connecting metal layer 4221 is connected to the through hole 4211.
  • the respective diameters of the three outer auxiliary holes 4211a may be the same.
  • the diameter of the outer auxiliary hole 4211a is larger than that of the middle base hole 4211b.
  • the diameters of the three outer auxiliary holes 4211a are equal to 1.3 times the diameter of the middle basic hole 4211b.
  • the diameter of one outer auxiliary hole 4211a is greater than 1.1 times the diameter of the middle basic hole 4211b.
  • the diameter of the other outer auxiliary hole 4211a is greater than or equal to 1 times the diameter of the middle basic hole 4211b.
  • the diameter of the other outer auxiliary hole 4211a is greater than or equal to 1.1 times the diameter of the middle basic hole 4211b.
  • the first connection metal layer 4221 is disposed within the through hole 4211 .
  • the cross-sectional shape of the middle channel 4221 a of the first connecting metal layer 4221 is the same as that of the through hole 4211 .
  • the first connecting metal layer 4221 is evenly disposed on the inner wall of the through hole 4211 , so that along a direction perpendicular to the inner wall, the thickness of each position of the first connecting metal layer 4221 is equal.
  • FIG. 22 schematically shows a partial structure of a flexible dielectric layer 421 according to an embodiment.
  • the same parts of the through hole 4211 in this embodiment and the through hole 4211 in the embodiment shown in FIG. 21 will not be described again, and the differences are mainly described here.
  • each outer auxiliary hole 4211a has two intersection points with the middle basic hole 4211b.
  • the through hole 4211 formed by the outer auxiliary hole 4211a and the middle basic hole 4211b in this embodiment is called a sixth type hole.
  • intersection point P1 is intersection point P1 and intersection point P2 and intersection point P3
  • intersection point P2 is intersection point P3
  • the intersection P1, the intersection P2 and the intersection P3 are arranged at intervals, and there is one intersection between the adjacent two.
  • the area defined by the line connecting the intersection point P1, the intersection point P2 and the intersection point P3 is triangular.
  • the angle ⁇ between the line connecting the intersection point P1 and the intersection point P2 and the line connecting the intersection point P2 and the intersection point P3 ranges from 15° to 90°.
  • the angle may be, but not limited to, 30°, 45°, 50°, 60°, 70°, 80°, 90°.
  • the diameter of the outer auxiliary hole 4211a may be greater than the diameter of the middle basic hole 4211b.
  • the respective diameters of the three outer auxiliary holes 4211a may be the same.
  • the diameters of the three outer auxiliary holes 4211a are equal to 1.3 times the diameter of the middle basic hole 4211b.
  • the diameter of one outer auxiliary hole 4211a is greater than 1.1 times the diameter of the middle basic hole 4211b.
  • the diameter of the other outer auxiliary hole 4211a is greater than or equal to 1 times the diameter of the middle basic hole 4211b.
  • the diameter of the other outer auxiliary hole 4211a is greater than or equal to 1.1 times the diameter of the middle basic hole 4211b.
  • the diameter of the outer auxiliary hole 4211a may be smaller than the diameter of the middle basic hole 4211b.
  • the diameters of the respective outer auxiliary holes 4211a are equal, and the diameter of the outer auxiliary holes 4211a is 0.8 times the diameter of the middle basic hole 4211b.
  • the first connection metal layer 4221 is disposed within the through hole 4211 .
  • the cross-sectional shape of the middle channel 4221 a of the first connecting metal layer 4221 is the same as that of the through hole 4211 .
  • the first connecting metal layer 4221 is evenly disposed on the inner wall of the through hole 4211 , so that along a direction perpendicular to the inner wall, the thickness of each position of the first connecting metal layer 4221 is equal.
  • FIG. 23 schematically shows a partial structure of a flexible dielectric layer 421 according to an embodiment.
  • four outer auxiliary holes 4211a are distributed along the Y direction of the middle basic hole 4211b.
  • the through hole 4211 formed by the outer auxiliary hole 4211a and the middle basic hole 4211b in this embodiment is referred to as a seventh type hole.
  • the inner wall area of the through-hole 4211 formed by the four outer auxiliary holes 4211a and one middle basic hole 4211b is relatively larger, thereby further increasing the contact area between the first connecting metal layer 4221 and the inner wall of the through-hole 4211.
  • intersections between the orthographic projections of the outer auxiliary holes 4211a and the middle basic holes 4211b form intersections P1, P2, P3 and P4.
  • the area defined by the lines connecting the intersection point P1, the intersection point P2, the intersection point P3 and the intersection point P4 is a quadrilateral, such as a trapezoid or a rectangle.
  • the line connecting the intersection point P1 and the intersection point P3 and the line connecting the intersection point P2 and the intersection point P4 intersect and the included angle ⁇ may range from 15° to 135°.
  • the line connecting the intersection point P1 and the intersection point P3 and the line connecting the intersection point P2 and the intersection point P4 intersect and the included angle ⁇ ranges from 30° to 90°.
  • the included angle ⁇ may be, but not limited to, 30°, 45°, 50°, 60°, 70°, 80°, 90°.
  • the four outer auxiliary holes 4211a can be arranged tangentially, and the intersection points P1 , P2 , P3 and P4 are respectively tangent points.
  • the four outer auxiliary holes 4211a are evenly distributed along the circumferential direction Y of the middle basic hole 4211b, so that after the first connecting metal layer 4221 is connected to the inner wall of the through hole 4211, it is beneficial to ensure that the first connecting metal layer 4221 is connected to the through hole 4211.
  • the diameter of the outer auxiliary hole 4211a is equal to the diameter of the middle base hole 4211b.
  • Each of the four outer auxiliary holes 4211a has the same diameter.
  • the diameter of one outer auxiliary hole 4211a is greater than 1.1 times the diameter of the middle basic hole 4211b.
  • the diameter of the other outer auxiliary hole 4211a is greater than or equal to 1 times the diameter of the middle basic hole 4211b.
  • the diameters of the remaining two outer auxiliary holes 4211a are greater than or equal to 1.1 times the diameter of the middle basic hole 4211b.
  • the first connection metal layer 4221 is disposed within the through hole 4211 .
  • the cross-sectional shape of the middle channel 4221 a of the first connecting metal layer 4221 is the same as that of the through hole 4211 .
  • the first connecting metal layer 4221 is evenly disposed on the inner wall of the through hole 4211 , so that along a direction perpendicular to the inner wall, the thickness of each position of the first connecting metal layer 4221 is equal.
  • FIG. 24 schematically shows a partial structure of a flexible dielectric layer 421 according to an embodiment.
  • the same parts of the through hole 4211 in this embodiment and the through hole 4211 in the embodiment shown in FIG. 23 will not be repeated, and the differences are mainly described here.
  • the four outer auxiliary holes 4211a are distributed along the circumferential direction Y of the middle basic hole 4211b.
  • Each outer auxiliary hole 4211a has two intersection points with the middle basic hole 4211b.
  • the through hole 4211 formed by the outer auxiliary hole 4211a and the middle basic hole 4211b in this embodiment is called an eighth type hole.
  • intersection point is selected from the two intersection points between each outer auxiliary hole 4211a and the middle basic hole 4211b, and the four intersection points are respectively intersection point P1, intersection point P2, intersection point P3 and intersection point P4.
  • the intersection P1, the intersection P2, the intersection P3 and the intersection P4 are arranged at intervals, and there is one intersection between the two adjacent ones.
  • the area defined by the lines connecting the intersection point P1, the intersection point P2, the intersection point P3 and the intersection point P4 is a quadrilateral, such as a trapezoid or a rectangle.
  • the four outer auxiliary holes 4211a are evenly distributed along the circumferential direction Y of the middle basic hole 4211b.
  • the four outer auxiliary holes 4211a are spaced apart from each other.
  • the diameter of the outer auxiliary hole 4211a is larger than that of the middle base hole 4211b.
  • Each of the four outer auxiliary holes 4211a has the same diameter.
  • the diameters of the four outer auxiliary holes 4211a are equal to 1.3 times the diameter of the middle basic hole 4211b.
  • the diameter of one outer auxiliary hole 4211a is greater than 1.1 times the diameter of the middle basic hole 4211b.
  • the diameter of the other outer auxiliary hole 4211a is greater than or equal to 1 times the diameter of the middle basic hole 4211b.
  • the diameters of the remaining two outer auxiliary holes 4211a are greater than or equal to 1.1 times the diameter of the middle basic hole 4211b.
  • the diameter of the outer auxiliary hole 4211a may be smaller than the diameter of the middle basic hole 4211b.
  • the diameters of the respective outer auxiliary holes 4211a are equal, and the diameter of the outer auxiliary holes 4211a is 0.8 times the diameter of the middle basic hole 4211b.
  • the first connection metal layer 4221 is disposed within the through hole 4211 .
  • the cross-sectional shape of the middle channel 4221 a of the first connecting metal layer 4221 is the same as that of the through hole 4211 .
  • the first connecting metal layer 4221 is evenly disposed on the inner wall of the through hole 4211 , so that along a direction perpendicular to the inner wall, the thickness of each position of the first connecting metal layer 4221 is equal.
  • FIG. 25 schematically shows a partial cross-sectional structure of a flexible circuit board 42 according to an embodiment.
  • the cross-sectional shape of the middle channel 4221 a of the first connecting metal layer 4221 is the same as the cross-sectional shape of the through hole 4211 .
  • the first connecting metal layer 4221 is evenly disposed on the inner wall of the through hole 4211 , so that along a direction perpendicular to the inner wall, the thickness of each position of the first connecting metal layer 4221 is equal.
  • the center of the middle channel 4221a of the first connecting metal layer 4221 coincides with the center of the through hole 4211, so that the center of the middle channel 4221a is aligned with the center of the pad 411 on the printed circuit board 41 to ensure that the welding lead
  • the relative position of the foot 422 and the pad 411 meets the requirement of position accuracy.
  • FIG. 26 schematically shows a partial cross-sectional structure of a flexible circuit board 42 according to an embodiment.
  • the soldering pin 422 of the flexible circuit board 42 further includes a second connection metal layer 4222 and a third connection metal layer 4223 .
  • the second connection metal layer 4222 and the third connection metal layer 4223 are respectively disposed on two sides of the flexible dielectric layer 421 .
  • the second connection metal layer 4222 and the third connection metal layer 4223 are respectively connected to the first connection metal layer 4221 .
  • the second connection metal layer 4222 includes a first through hole 4222a communicating with the intermediate channel 4221a.
  • the third connection metal layer 4223 includes a second via hole 4223a communicating with the intermediate channel 4221a.
  • the second connection metal layer 4222 is used to connect with the metal wire 423 .
  • the second connection metal layer 4222 has the same shape as the defined region 42a. Edges of the second connection metal layer 4222 may be aligned with boundaries of the defined region 42a. After the melted solder paste 70 overflows from the side of the flexible dielectric layer 421 facing away from the pad 411 , the solder paste 70 will flow to the surface of the second connection metal layer 4222 facing away from the pad 411 . After the solder paste 70 solidifies, it is connected to the second connection metal layer 4222 .
  • the third connecting metal layer 4223 is used to face the pad 411 of the printed circuit board 41 and be soldered to the pad 411 .
  • the second connection metal layer 4222 and the third connection metal layer 4223 are respectively connected to the flexible dielectric layer 421 , so as to further improve the bonding force between the flexible dielectric layer 421 and the welding pin 422 .
  • the shape of the first through hole 4222 a of the second connection metal layer 4222 and the second through hole 4223 a of the third connection metal layer 4223 are respectively the same as the shape of the middle channel 4221 a of the first connection metal layer 4221 .
  • the second connection metal layer 4222 has a circular structure or a rectangular structure.
  • the third connecting metal layer 4223 has a circular structure or a rectangular structure.
  • the second connection metal layer 4222 and the third connection metal layer 4223 are formed by electroless plating.
  • the flexible dielectric layer 421 includes two insulating base layers 421a.
  • the through hole 4211 runs through the two insulating base layers 421a.
  • the solder pins 422 of the flexible circuit board 42 also include a fourth connection metal layer.
  • the fourth connection metal layer is connected to the first connection metal layer 4221 , and the fourth connection metal layer is disposed between two insulating base layers 421a.
  • the fourth connection metal layer is connected to the flexible dielectric layer 421 , so as to further improve the bonding force between the flexible dielectric layer 421 and the welding pin 422 .
  • the first connecting metal layer 4221 , the second connecting metal layer 4222 , the third connecting metal layer 4223 and the fourth connecting metal layer are integrally formed.
  • FIG. 27 schematically shows a partial cross-sectional structure of the connection state of the flexible circuit board 42 and the printed circuit board 41 of an embodiment.
  • the melted solder paste 70 solidifies to form solder joints 80 .
  • the solder joint 80 includes a first connection portion 81 , a connection post 82 and a second connection portion 83 .
  • the first connection part 81 is located between the pad 411 and the flexible dielectric layer 421 .
  • the first connecting portion 81 blocks the opening of the middle channel 4221 a facing the printed circuit board 41 .
  • the second connecting portion 83 is located on a side of the flexible dielectric layer 421 facing away from the printed circuit board 41 .
  • the second connecting portion 83 blocks the opening of the middle channel 4221a facing away from the printed circuit board 41 .
  • the connecting post 82 is located in the middle channel 4221a.
  • the first connecting portion 81 and the second connecting portion 83 are respectively connected to the connecting posts 82 .
  • the first connection portion 81 is connected to the surface of the third connection metal layer 4223 facing the pad 411 .
  • the second connection portion 83 is connected to the second connection metal layer 4222 .
  • Table 1 exemplarily shows that the middle channel 4221a of the first connecting metal layer 4221 in the related art is a circular hole, and the first connecting metal layer 4221a of the embodiment of the present application
  • the middle channel 4221a of the layer 4221 is the data of the first type hole, the second type hole and the seventh type hole.
  • the parameter H in Table 1 represents the measured depth of the middle channel 4221a along the axial direction of the middle channel 4221a.
  • the axial direction of the middle channel 4221a is the same as the thickness direction X of the flexible dielectric layer 421 .
  • the depth H of the circular hole, the depth H of the first type of hole, the depth H of the second type of hole, and the depth H of the seventh type of hole take the same value.
  • the different shapes of the intermediate channel 4221a of the first connecting metal layer 4221 will result in different hole wall areas of the intermediate channel 4221a.
  • the area of the hole wall of the middle channel 4221a is S1.
  • the wall areas of the intermediate channel 4221a are S2, S3 and S4 respectively. Among them, S3>S4>S2>S1.
  • the cross-sectional shape of the middle channel 4221a of the first connection metal layer 4221 is the same as the cross-sectional shape of the through hole 4211.
  • the size of the hole wall area of the middle channel 4221a is positively related to the size of the contact area between the first connecting metal layer 4221 and the flexible dielectric layer 421. Therefore, in this application, by setting the through hole 4211 as the difference between the outer auxiliary hole 4211a and the middle basic hole 4211b In this way, the contact area between the first connecting metal layer 4221 and the flexible dielectric layer 421 can be relatively increased, thereby improving the bonding force between the first connecting metal layer 4221 and the flexible dielectric layer 421 .
  • connection should be understood in a broad sense, for example, it can be a fixed connection or a An indirect connection through an intermediary may be an internal communication between two elements or an interaction relationship between two elements.
  • plural herein means two or more.
  • the term “and/or” in this article is just an association relationship describing associated objects, which means that there can be three relationships, for example, A and/or B can mean: A exists alone, A and B exist simultaneously, and there exists alone B these three situations.
  • the character "/" in this paper generally indicates that the contextual objects are an “or” relationship; in the formula, the character "/" indicates that the contextual objects are a "division" relationship.
  • sequence numbers of the above-mentioned processes do not mean the order of execution, and the order of execution of the processes should be determined by their functions and internal logic, and should not be used in the implementation of this application.
  • the implementation of the examples constitutes no limitation.

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  • Structure Of Printed Boards (AREA)
  • Printing Elements For Providing Electric Connections Between Printed Circuits (AREA)

Abstract

本申请实施例提供一种柔性电路板、电路板组件以及电子设备。柔性电路板至少包括柔性介电层和第一连接金属层。柔性介电层包括沿柔性介电层的厚度方向延伸的贯通孔。贯通孔包括中间基础孔和外侧辅助孔。两个以上的外侧辅助孔沿中间基础孔的周向分布设置。中间基础孔连通两个以上的外侧辅助孔。第一连接金属层设置于贯通孔的内壁并且与柔性介电层相连。第一连接金属层包括沿厚度方向延伸的中间通道。本申请实施例的柔性电路板能够降低柔性电路板在焊接处发生撕裂的情况。

Description

柔性电路板、电路板组件以及电子设备
本申请要求于2021年09月27日提交中国国家知识产权局、申请号为202111137418.3、申请名称为“柔性电路板、电路板组件以及电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请实施例涉及终端技术领域，特别涉及一种柔性电路板、电路板组件以及电子设备。
背景技术
随着手机、平板电脑(portable equipment，PAD)和笔记本电脑等电子设备的爆发式增长，这些电子书设备日渐成为现代人生活的必需品之一，从而在现代生活、工作联络等各种场景下作用愈来愈重要。电子设备中通常设置有印制电路板Printed Circuit Board，PCB)和柔性电路板(Flexible Printed Circuit，FPC)。在一些情况下，印制电路板和柔性电路板需要彼此相连以实现电连接。例如，通过板对板连接器(board to board，BTB)实现印制电路板和柔性电路板相连。印制电路板和柔性电路板分别设置有一个板对板连接器。通过两个板对板连接器的相互插接以实现印制电路板和柔性电路板相互连接。然而，由于板对板连接器自身的体积较大，因此板对板连接器需要占用较大的安装空间，从而不利于电子设备的小型化。为了替代板对板连接器，采用软板-硬板板间互连(FPC on board，FOB)技术将柔性电路板和印制电路板焊接连接。但是，在对完成焊接后的柔性电路板和印制电路板进行装配过程中，柔性电路板易于发生损坏，例如柔性电路板在焊接处发生撕裂现象，从而导致柔性电路板失效报废。
发明内容
本申请实施例提供一种柔性电路板、电路板组件以及电子设备，能够降低柔性电路板在焊接处发生撕裂的情况。
本申请第一方面提供一种柔性电路板。柔性电路板至少包括柔性介电层和第一连接金属层。柔性介电层包括沿柔性介电层的厚度方向延伸的贯通孔。贯通孔包括中间基础孔和外侧辅助孔。两个以上的外侧辅助孔沿中间基础孔的周向分布设置。中间基础孔连通两个以上的外侧辅助孔。第一连接金属层设置于贯通孔的内壁并且与柔性介电层相连。第一连接金属层包括沿厚度方向延伸的中间通道。
本申请实施例的柔性电路板包括柔性介电层和第一连接金属层。柔性介电层上设置有贯通孔。贯通孔包括中间基础孔和外侧辅助孔。相对于相关技术中贯通孔为单独的圆形孔的实施例，由于两个以上的外侧辅助孔沿中间基础孔的周向分布设置，因此贯通孔的形状与圆形孔的形状不同。本申请通过将贯通孔设置为外侧辅助孔和中间基础孔的方式，使得在限定区域内可以相对地增大第一连接金属层和柔性介电层的接触面积，从而有利于提高第一连接金属层和柔性介电层之间的结合力。因此，本申请实 施例的第一连接金属层与柔性介电层之间的结合力大于贯通孔为圆形孔时第一连接金属层与柔性介电层之间的结合力，从而柔性介电层和第一连接金属层之间的连接处可以承载更大的拉伸力。本申请实施例的柔性电路板与印制电路板相连，并且柔性介电层在装配过程中受到拉伸力作用时，柔性介电层和第一连接金属层不易发生分离，从而有利于降低柔性介电层和第一连接金属层脱离连接而出现撕裂情况的可能性。
在一种可能的实施方式中，沿中间基础孔的周向，两个以上的外侧辅助孔均匀分布，从而可以保证贯通孔的整体形状规整，有利于提高贯通孔的内壁和第一连接金属层之间连接区域的受力均衡性，保证贯通孔的内壁和第一连接金属层之间连接稳定性。
在一种可能的实施方式中，外侧辅助孔的轴线与中间基础孔的轴线相互平行，从而外侧辅助孔和中间基础孔的延伸方向相同，易于加工制造。
在一种可能的实施方式中，中间基础孔和外侧辅助孔均为圆形孔，从而易于采用激光烧蚀或机械钻孔的方式加工制造，降低因贯通孔自身形状不规整而使得加工制造难度大，导致柔性介电层的良品率偏低的可能性。
在一种可能的实施方式中，沿厚度方向，各个外侧辅助孔的正投影和中间基础孔的正投影之间相交形成有交点P1、交点P2、交点P3和交点P4。中间基础孔的轴线位于交点P1、交点P2、交点P3和交点P4的连线所限定的区域内侧。外侧辅助孔的轴线位于交点P1、交点P2、交点P3和交点P4的连线所限定的区域外侧。
在一种可能的实施方式中，交点P1和交点P3的连线以及交点P2和交点P4的连线相交并且夹角范围为15°至135°。
在一种可能的实施方式中，两个外侧辅助孔分别位于中间基础孔的两侧。外侧辅助孔与中间基础孔相连通。两个外侧辅助孔的轴线以及中间基础孔的轴线位于同一平面内。
在一种可能的实施方式中，四个外侧辅助孔环绕中间基础孔的轴线设置。四个外侧辅助孔和一个中间基础孔形成的贯通孔的内壁面积相对更大，从而进一步增大第一连接金属层与贯通孔的内壁的接触面积，有利于进一步提高第一连接金属层与贯通孔的内壁的结合力。
在一种可能的实施方式中，沿厚度方向，各个外侧辅助孔的正投影和中间基础孔的正投影之间相交形成有交点P1、交点P2和交点P3。中间基础孔的轴线位于交点P1、交点P2和交点P3的连线所限定的区域内侧。外侧辅助孔的轴线位于交点P1、交点P2和交点P3的连线所限定的区域外侧。
在一种可能的实施方式中，交点P1和交点P2的连线以及交点P2和交点P3的连线之间的夹角范围为15°至90°。
在一种可能的实施方式中，三个外侧辅助孔环绕中间基础孔的轴线设置。
在一种可能的实施方式中，外侧辅助孔的直径大于中间基础孔的直径。
在一种可能的实施方式中，各个外侧辅助孔的直径相等。外侧辅助孔的直径是中间基础孔的直径的1.3倍。
在一种可能的实施方式中，外侧辅助孔的直径小于中间基础孔的直径。
在一种可能的实施方式中，各个外侧辅助孔的直径相等。外侧辅助孔的直径是中间基础孔的直径的0.8倍。
在一种可能的实施方式中，柔性电路板还包括第二连接金属层和第三连接金属层。沿厚度方向，第二连接金属层和第三连接金属层分别设置于柔性介电层的两侧。第二连接金属层和第三连接金属层分别与第一连接金属层相连。第二连接金属层包括与中间通道相连通的第一通孔。第三连接金属层包括与中间通道相连通的第二通孔。第二连接金属层和第三连接金属层分别与柔性介电层相连，从而有利于进一步提高柔性介电层和焊接引脚之间的结合力。
在一种可能的实施方式中，柔性介电层包括两层绝缘基层。贯通孔贯穿两层绝缘基层。柔性电路板还包括第四连接金属层。第四连接金属层与第一连接金属层相连，并且第四连接金属层设置于两层绝缘基层之间。
本申请实施例第二方面提供一种电路板组件。电路板组件至少包括印制电路板和柔性电路板。印制电路板包括焊盘。柔性电路板至少包括柔性介电层和第一连接金属层。柔性介电层包括沿柔性介电层的厚度方向延伸的贯通孔。贯通孔包括中间基础孔和外侧辅助孔。两个以上的外侧辅助孔沿中间基础孔的周向分布设置。中间基础孔连通两个以上的外侧辅助孔。第一连接金属层设置于贯通孔的内壁并且与柔性介电层相连。第一连接金属层包括沿厚度方向延伸的中间通道。焊盘和第一连接金属层通过焊点焊接，焊点的一部分填充于中间通道内。
在一种可能的实施方式中，沿中间基础孔的周向，两个以上的外侧辅助孔均匀分布，从而可以保证贯通孔的整体形状规整，有利于提高贯通孔的内壁和第一连接金属层之间连接区域的受力均衡性，保证贯通孔的内壁和第一连接金属层之间连接稳定性。
在一种可能的实施方式中，外侧辅助孔的轴线与中间基础孔的轴线相互平行，从而外侧辅助孔和中间基础孔的延伸方向相同，易于加工制造。
在一种可能的实施方式中，中间基础孔和外侧辅助孔均为圆形孔，从而易于采用激光烧蚀或机械钻孔的方式加工制造，降低因贯通孔自身形状不规整而使得加工制造难度大，导致柔性介电层的良品率偏低的可能性。
在一种可能的实施方式中，沿厚度方向，各个外侧辅助孔的正投影和中间基础孔的正投影之间相交形成有交点P1、交点P2、交点P3和交点P4。中间基础孔的轴线位于交点P1、交点P2、交点P3和交点P4的连线所限定的区域内侧。外侧辅助孔的轴线位于交点P1、交点P2、交点P3和交点P4的连线所限定的区域外侧。
在一种可能的实施方式中，交点P1和交点P3的连线以及交点P2和交点P4的连线相交并且夹角范围为15°至135°。
在一种可能的实施方式中，两个外侧辅助孔分别位于中间基础孔的两侧。外侧辅助孔与中间基础孔相连通。两个外侧辅助孔的轴线以及中间基础孔的轴线位于同一平面内。
在一种可能的实施方式中，四个外侧辅助孔环绕中间基础孔的轴线设置。四个外侧辅助孔和一个中间基础孔形成的贯通孔的内壁面积相对更大，从而进一步增大第一连接金属层与贯通孔的内壁的接触面积，有利于进一步提高第一连接金属层与贯通孔的内壁的结合力。
在一种可能的实施方式中，沿厚度方向，各个外侧辅助孔的正投影和中间基础孔的正投影之间相交形成有交点P1、交点P2和交点P3。中间基础孔的轴线位于交点P1、 交点P2和交点P3的连线所限定的区域内侧。外侧辅助孔的轴线位于交点P1、交点P2和交点P3的连线所限定的区域外侧。
在一种可能的实施方式中，交点P1和交点P2的连线以及交点P2和交点P3的连线之间的夹角范围为15°至90°。
在一种可能的实施方式中，三个外侧辅助孔环绕中间基础孔的轴线设置。
在一种可能的实施方式中，外侧辅助孔的直径大于中间基础孔的直径。
在一种可能的实施方式中，各个外侧辅助孔的直径相等。外侧辅助孔的直径是中间基础孔的直径的1.3倍。
在一种可能的实施方式中，外侧辅助孔的直径小于中间基础孔的直径。
在一种可能的实施方式中，各个外侧辅助孔的直径相等。外侧辅助孔的直径是中间基础孔的直径的0.8倍。
在一种可能的实施方式中，柔性电路板还包括第二连接金属层和第三连接金属层。沿厚度方向，第二连接金属层和第三连接金属层分别设置于柔性介电层的两侧。第二连接金属层和第三连接金属层分别与第一连接金属层相连。第二连接金属层包括与中间通道相连通的第一通孔。第三连接金属层包括与中间通道相连通的第二通孔。第二连接金属层和第三连接金属层分别与柔性介电层相连，从而有利于进一步提高柔性介电层和焊接引脚之间的结合力。
在一种可能的实施方式中，柔性介电层包括两层绝缘基层。贯通孔贯穿两层绝缘基层。柔性电路板还包括第四连接金属层。第四连接金属层与第一连接金属层相连，并且第四连接金属层设置于两层绝缘基层之间。
本申请实施例第三方面提供一种电子设备。电子设备至少包括上述的电路板组件。电路板组件至少包括印制电路板和柔性电路板。印制电路板包括焊盘。柔性电路板至少包括柔性介电层和第一连接金属层。柔性介电层包括沿柔性介电层的厚度方向延伸的贯通孔。贯通孔包括中间基础孔和外侧辅助孔。两个以上的外侧辅助孔沿中间基础孔的周向分布设置。中间基础孔连通两个以上的外侧辅助孔。第一连接金属层设置于贯通孔的内壁并且与柔性介电层相连。第一连接金属层包括沿厚度方向延伸的中间通道。焊盘和第一连接金属层通过焊点焊接，焊点的一部分填充于中间通道内。
在一种可能的实施方式中，沿中间基础孔的周向，两个以上的外侧辅助孔均匀分布，从而可以保证贯通孔的整体形状规整，有利于提高贯通孔的内壁和第一连接金属层之间连接区域的受力均衡性，保证贯通孔的内壁和第一连接金属层之间连接稳定性。
在一种可能的实施方式中，外侧辅助孔的轴线与中间基础孔的轴线相互平行，从而外侧辅助孔和中间基础孔的延伸方向相同，易于加工制造。
在一种可能的实施方式中，中间基础孔和外侧辅助孔均为圆形孔，从而易于采用激光烧蚀或机械钻孔的方式加工制造，降低因贯通孔自身形状不规整而使得加工制造难度大，导致柔性介电层的良品率偏低的可能性。
在一种可能的实施方式中，沿厚度方向，各个外侧辅助孔的正投影和中间基础孔的正投影之间相交形成有交点P1、交点P2、交点P3和交点P4。中间基础孔的轴线位于交点P1、交点P2、交点P3和交点P4的连线所限定的区域内侧。外侧辅助孔的轴 线位于交点P1、交点P2、交点P3和交点P4的连线所限定的区域外侧。
在一种可能的实施方式中，交点P1和交点P3的连线以及交点P2和交点P4的连线相交并且夹角范围为15°至135°。
在一种可能的实施方式中，两个外侧辅助孔分别位于中间基础孔的两侧。外侧辅助孔与中间基础孔相连通。两个外侧辅助孔的轴线以及中间基础孔的轴线位于同一平面内。
在一种可能的实施方式中，四个外侧辅助孔环绕中间基础孔的轴线设置。四个外侧辅助孔和一个中间基础孔形成的贯通孔的内壁面积相对更大，从而进一步增大第一连接金属层与贯通孔的内壁的接触面积，有利于进一步提高第一连接金属层与贯通孔的内壁的结合力。
在一种可能的实施方式中，沿厚度方向，各个外侧辅助孔的正投影和中间基础孔的正投影之间相交形成有交点P1、交点P2和交点P3。中间基础孔的轴线位于交点P1、交点P2和交点P3的连线所限定的区域内侧。外侧辅助孔的轴线位于交点P1、交点P2和交点P3的连线所限定的区域外侧。
在一种可能的实施方式中，交点P1和交点P2的连线以及交点P2和交点P3的连线之间的夹角范围为15°至90°。
在一种可能的实施方式中，三个外侧辅助孔环绕中间基础孔的轴线设置。
在一种可能的实施方式中，外侧辅助孔的直径大于中间基础孔的直径。
在一种可能的实施方式中，各个外侧辅助孔的直径相等。外侧辅助孔的直径是中间基础孔的直径的1.3倍。
在一种可能的实施方式中，外侧辅助孔的直径小于中间基础孔的直径。
在一种可能的实施方式中，各个外侧辅助孔的直径相等。外侧辅助孔的直径是中间基础孔的直径的0.8倍。
在一种可能的实施方式中，柔性电路板还包括第二连接金属层和第三连接金属层。沿厚度方向，第二连接金属层和第三连接金属层分别设置于柔性介电层的两侧。第二连接金属层和第三连接金属层分别与第一连接金属层相连。第二连接金属层包括与中间通道相连通的第一通孔。第三连接金属层包括与中间通道相连通的第二通孔。第二连接金属层和第三连接金属层分别与柔性介电层相连，从而有利于进一步提高柔性介电层和焊接引脚之间的结合力。
在一种可能的实施方式中，柔性介电层包括两层绝缘基层。贯通孔贯穿两层绝缘基层。柔性电路板还包括第四连接金属层。第四连接金属层与第一连接金属层相连，并且第四连接金属层设置于两层绝缘基层之间。
附图说明
图1为本申请一实施例的电子设备的结构示意图；
图2为本申请一实施例的电子设备的局部分解结构示意图；
图3为本申请一实施例的印制电路板的结构示意图；
图4为相关技术中的电路板组件的局部结构示意图；
图5为相关技术中的柔性电路板的局部剖视结构示意图；
图6为图4中A处放大图；
图7为印制电路板的焊盘上设置焊膏的局部剖视结构示意图；
图8为印制电路板、焊膏和柔性电路板连接时的第一状态示意图；
图9为印制电路板、焊膏和柔性电路板连接时的第二状态示意图；
图10为印制电路板与柔性电路板连接状态的局部剖视结构示意图；
图11为柔性介电层和焊接引脚处于分离状态示意图；
图12为本申请一实施例的柔性电路板的局部结构示意图；
图13为图12中B处放大图；
图14为本申请一实施例的柔性介电层的局部结构示意图；
图15为图14中C处放大图；
图16为本申请另一实施例的柔性介电层的局部结构示意图；
图17为图16中D处放大图；
图18为本申请又一实施例的柔性介电层的局部结构示意图；
图19为本申请又一实施例的柔性介电层的局部结构示意图；
图20为图19中E处放大图；
图21为本申请又一实施例的柔性介电层的局部结构示意图；
图22为本申请又一实施例的柔性介电层的局部结构示意图；
图23为本申请又一实施例的柔性介电层的局部结构示意图；
图24为本申请再一实施例的柔性介电层的局部结构示意图；
图25为本申请一实施例的柔性电路板的局部剖视结构示意图；
图26为本申请另一实施例的柔性电路板的局部剖视结构示意图；
图27为图26所示实施例的柔性电路板与印制电路板连接状态的局部剖视结构示意图；
图28为相关技术中的柔性电路板的局部剖视结构示意图；
图29为本申请一实施例的柔性电路板的局部剖视结构示意图；
图30为不同形状的中间通道的孔壁面积比较示意图。
附图标记说明：
10、电子设备；
20、显示组件；
30、中框；
40、电路板组件；
41、印制电路板；41a、焊接区域；411、焊盘；412、金属导线；413、阻挡部；
42、柔性电路板；42a、限定区域；
421、柔性介电层；421a、绝缘基层；4211、贯通孔；4211a、外侧辅助孔；4211b、中间基础孔；
422、焊接引脚；4221、第一连接金属层；4221a、中间通道；4222、第二连接金属层；4222a、第一通孔；4223、第三连接金属层；4223a、第二通孔；4224、第四连接金属层；
423、金属走线；
50、后壳；
60、电子器件；
70、焊膏；
80、焊点；81、第一连接部；82、连接柱；83、第二连接部；
aa、轴线；
bb、轴线；
X、厚度方向；
Y、周向。
具体实施方式
本申请实施例中的电子设备10可以称为用户设备(user equipment，UE)、终端(terminal)等，例如，电子设备10可以为平板电脑(portable android device，PAD)、个人数字处理(personal digital assistant，PDA)、具有无线通信功能的手持设备、计算设备、车载设备、可穿戴设备、虚拟现实(virtual reality，VR)终端设备、增强现实(augmented reality，AR)终端设备、工业控制(industrial control)中的无线终端、无人驾驶(self driving)中的无线终端、远程医疗(remote medical)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端、智慧家庭(smart home)中的无线终端等移动终端或固定终端。本申请实施例中对终端设备的形态不做具体限定。
本申请实施例中，以电子设备10为具有无线通信功能的手持设备为例进行说明。图1示意性地显示了一实施例的电子设备10的结构。参见图1所示，无线通信功能的手持设备例如可以是手机。
图2示意性地显示了一实施例的电子设备10的局部分解结构。参见图1和图2所示，本申请实施例的电子设备10包括显示组件20、中框30、电路板组件40和后壳50。显示组件20具有用于显示图像信息的显示区域。显示组件20的显示区域背向中框30。在通电状态下，显示区域可以显示相应的图像信息。沿电子设备10的厚度方向，中框30设置于显示组件20和后壳50之间。需要说明的是，电子设备10的厚度方向指的是显示组件20和后壳50的排列方向。电路板组件40设置于中框30和后壳50之间形成的空间内，并且位于显示组件20的内侧，从而用户在电子设备10的外部不易观察到电路板组件40。电路板组件40可以设置于中框30面向后壳50的表面上。
电路板组件40包括印制电路板41(Printed Circuit Board，PCB)和柔性电路板42(Flexible Printed Circuit，FPC)。
图3示意性地显示了印制电路板41的结构。参见图3所示，印制电路板41可以是单面板或双面板。单面板指的是印制电路板41的一侧设置有电子器件60。双面板指的是印制电路板41的两侧均设置有电子器件60。印制电路板41可以是射频(radio frequency，RF)板、应用处理器(application processor，AP)板。射频板可以但不限于用于承载射频芯片(radio frequencyintegrated circuit，RFIC)、射频功率放大器(radio frequency power amplifier，RFPA)和无线保真(wireless fidelity，WIFI)芯片等。应用处理器板例如可以但不限于用于承载片上系统(system on chip，SOC)元件、双倍数据率 (double data rate，DDR)存储器、主电源管理芯片(power management unit，PMU)和辅电源管理芯片等。
柔性电路板42用于连接功能模块以及印制电路板41上相对应的电子器件60。例如，柔性电路板42可以连接摄像模块和印制电路板41上的图形处理芯片。或者，柔性电路板42可以连接显示组件20和印制电路板41上的显示以及操作芯片。为了减小包括印制电路板41和柔性电路板42的电路板组件40自身体积，采用柔性电路板42和印制电路板41直接连接的方式相连接，以取消使用板对板连接器。例如，柔性电路板42和印制电路板41通过焊接方式相连接。
印制电路板41的一侧设置有焊接区域41a。在焊接区域41a上设置有多个焊盘411。印制电路板41的各个焊盘411和印制电路板41上设置的电子器件60之间通过印制电路板41上的金属导线412电连接。示例性地，金属导线412和焊盘411的材料可以但不限于是铜或铜合金。
图4示意性地显示了电路板组件40的结构。图5示意性地显示了一实施例的柔性电路板42的局部结构。参见图4和图5所示，柔性电路板42包括柔性介电层421、焊接引脚422以及金属走线423。柔性介电层421为具有绝缘功能的层结构。柔性介电层421用于保持金属走线423之间或者焊接引脚422之间的绝缘状态。柔性介电层421的材料包括但不限于聚酰亚胺(Polyimide，PI)、热塑性聚酰亚胺(Thermoplastic polyimide，TPI)或聚酯(Polyethylene terephthalate，PET)。柔性介电层421具有良好的柔韧性，从而受外力作用时可以发生弯曲。柔性介电层421的厚度取值范围为0.05毫米至0.5毫米，例如可以但不限于为0.05毫米、0.075毫米、0.1毫米、0.11毫米、0.2毫米、0.3毫米、0.4毫米、0.5毫米。焊接引脚422和金属走线423设置于柔性介电层421。柔性电路板42包括多条金属走线423和多个焊接引脚422。多个焊接引脚422通常集中设置于一个区域并且多个焊接引脚422呈多排排列。不同的金属走线423与对应的焊接引脚422相连。柔性电路板42通过焊接引脚422与印制电路板41上相对应的焊盘411焊接连接，从而实现柔性电路板42和印制电路板41的导通。示例性地，焊接引脚422和金属走线423的材料可以但不限于是铜或铜合金。
参见图4至图6所示，相关技术中，柔性电路板42的柔性介电层421上设置有贯通孔4211，例如贯通孔4211可以是圆形孔。沿柔性介电层421的厚度方向X，柔性介电层421包括相对的两个表面，而贯通孔4211贯穿柔性介电层421的两个表面。示例性地，可以采用激光烧蚀或者机械钻孔的方式在柔性介电层421上形成贯通孔4211。贯通孔4211的数量与焊接引脚422的数量相等。每排贯通孔4211中，相邻两个贯通孔4211之间需要保持预定间距L。例如，预定间距L可以是0.6毫米。焊接引脚422包括第一连接金属层4221。第一连接金属层4221设置于贯通孔4211的内壁并且与柔性介电层421相连。示例性地，采用化学镀的方式在柔性介电层421的贯通孔4211的内壁上形成第一连接金属层4221。第一连接金属层4221和柔性介电层421相连并且两者之间具有预定的结合力。需要说明的是，结合力指的是使第一连接金属层4221和柔性介电层421分离时所需要克服的作用力。使第一连接金属层4221和柔性介电层421分离时所需要的作用力可以是沿贯通孔4211的径向，对柔性介电层421施加远离第一连接金属层4221方向并使得第一连接金属层4221和柔性介电层421发生分离时 所需要的拉应力。第一连接金属层4221包括沿柔性介电层421的厚度方向X延伸的中间通道4221a。相邻两个贯通孔4211之间的预定间距L指的是相邻两个贯通孔4211的轴线之间的垂直距离。示例性地，中间通道4221a的形状与贯通孔4211的形状相同，即中间通道4221a可以是圆形孔。中间通道4221a的横截面的最大尺寸为中间通道4221a的直径。中间通道4221a的直径可以但不限于为0.15毫米、0.2毫米、0.4毫米。
需要说明的是，印制电路板41上设置预定数量的焊盘411，则柔性电路板42上也需要设置同等数量的焊接引脚422。一个焊接引脚422对应一个焊盘411设置。例如，印制电路板41上设置30个焊盘411，则柔性电路板42上也需要设置30个焊接引脚422。如果相邻两个贯通孔4211之间的预定间距L发生变化，则相邻两个焊接引脚422之间的间距也会发生变化，从而导致柔性电路板42上的焊接引脚422不能与印制电路板41上的焊盘411对准。焊接引脚422不能与印制电路板41上的焊盘411对准焊接时，会造成焊接引脚422和焊盘411之间焊接质量偏差，完成焊接后的连接力偏小。需要说明的是，连接力指的是使焊接引脚422和焊盘411分离时所需要克服的作用力。使焊接引脚422和焊盘411分离时所需要的作用力可以是沿贯通孔4211的轴向，对焊接引脚422施加远离焊盘411方向并使得焊接引脚422和焊盘411发生分离时所需要的拉应力。针对一个柔性电路板42，由于相邻两个贯通孔4211之间的预定间距L是固定的，因此每个贯通孔4211自身所占用的面积是存在限制的。示例性地，在柔性电路板42上划分出对应数量的限定区域42a，并且每个限定区域42a对应设置一个贯通孔4211。
图7至图10示意性地显示了柔性电路板42和印制电路板41连接过程。在一些可实现的方式中，将柔性电路板42和印制电路板41进行连接的过程如下：
参见图7所示，在印制电路板41上的焊盘411上预先印刷焊膏70。例如，焊膏70中可以包含金属锡和助焊剂。参见图8所示，将柔性电路板42的焊接引脚422与对应的印制电路板41的焊盘411通过焊膏70接触。参见图9所示，在柔性电路板42背向焊盘411的一侧对柔性电路板42上设置焊接引脚422的区域施加朝向焊盘411的压应力。加热焊接引脚422与对应的焊盘411之间的焊膏70。例如，使用激光加热焊膏70。焊膏70吸收热量后发生熔化。由于柔性电路板42和印制电路板41可以挤压熔化后的焊膏70，因此熔化后的焊膏70一部分会进入第一连接金属层4221的中间通道4221a。沿柔性介电层421的厚度方向X，焊膏70在第一连接金属层4221的中间通道4221a内上升。参见图10所示，在焊膏70固化后，焊膏70形成焊点80，从而柔性电路板42的焊接引脚422与对应的印制电路板41的焊盘411通过焊点80相连接并实现导通。
示例性地，沿柔性介电层421的厚度方向X，焊膏70在第一连接金属层4221的中间通道4221a内上升并且从中间通道4221a背向焊盘411的开口中溢出。溢出的焊膏70可以覆盖中间通道4221a背向焊盘411的开口。
示例性地，印制电路板41的焊盘411尺寸大于第一连接金属层4221的中间通道4221a面向焊盘411的开口尺寸。柔性电路板42的焊接引脚422与对应的印制电路板41的焊盘411之间的焊膏70可以覆盖中间通道4221a面向焊盘411的开口。参见图7所示，印制电路板41的焊盘411周围可以设置阻挡部413。阻挡部413用于阻挡熔化 后的焊膏70向焊盘411以外的区域流动。柔性电路板42和阻挡部413接触，从而柔性电路板42的焊接引脚422与对应的印制电路板41的焊盘411之间形成有间隙。该间隙可以用于容纳焊膏70，从而降低熔化后的焊膏70从焊接引脚422与对应的焊盘411之间被挤出的可能性，进而降低因焊接引脚422与对应的焊盘411之间的焊膏70剩余量偏少而导致完成焊接后的焊接引脚422与对应的焊盘411之间的连接力偏小的可能性。
柔性电路板42的焊接引脚422与对应的印制电路板41的焊盘411通过焊点80连接后，相对于第一连接金属层4221与柔性介电层421之间的结合力，焊接引脚422与焊点80之间的结合力以及焊点80与对应的焊盘411之间的结合力相对较大。在电路板组件40与其他零部件进行装配过程中，存在柔性介电层421受到外部拉伸力作用的情况。图11示意性地显示了柔性介电层421和第一连接金属层4221分离状态。参见图11所示，当柔性介电层421承载的拉伸力大于柔性介电层421和第一连接金属层4221之间的结合力时，柔性介电层421和第一连接金属层4221之间会脱离连接状态而发生分离，从而柔性介电层421和第一连接金属层4221出现撕裂情况，导致柔性电路板42因发生损坏而失效报废，进而导致电路板组件40报废。
本申请实施例的柔性电路板42，可以提高柔性介电层421和第一连接金属层4221之间的结合力，使得柔性介电层421可以承载更大的拉伸力，从而有利于降低柔性介电层421承载拉伸力而导致柔性介电层421和第一连接金属层4221之间脱离连接状态而发生分离的可能性。
下面对本申请实施例提供的柔性电路板42的实现方式进行阐述。
图12示意性地显示了一实施例的柔性电路板42的局部结构。参见图12和图13所示，本申请实施例提供一种柔性电路板42。柔性电路板42包括柔性介电层421和第一连接金属层4221。柔性介电层421和第一连接金属层4221相连。柔性介电层421具有预定的厚度。柔性介电层421包括贯通孔4211。柔性介电层421在自身厚度方向上具有相对的两个表面。贯通孔4211的一个开口位于柔性介电层421的一个表面，另一个开口位于柔性介电层421的另一个表面。贯通孔4211包括外侧辅助孔4211a和中间基础孔4211b。两个以上的外侧辅助孔4211a沿中间基础孔4211b的周向Y分布设置。中间基础孔4211b连通两个以上的外侧辅助孔4211a。第一连接金属层4221设置于贯通孔4211的内壁并且与柔性介电层421相连。第一连接金属层4221面向贯通孔4211的内壁的外周表面的轮廓与贯通孔4211的内壁的轮廓相匹配并且保持接触状态。第一连接金属层4221包括沿厚度方向X延伸的中间通道4221a。
需要说明的是，中间基础孔4211b的周向Y指的是环绕中间基础孔4211b的轴线的方向。本申请实施例的柔性电路板42包括柔性介电层421和第一连接金属层4221。柔性介电层421上设置有贯通孔4211。贯通孔4211包括外侧辅助孔4211a和中间基础孔4211b。相对于相关技术中贯通孔4211为单独的圆形孔的实施例，由于两个以上的外侧辅助孔4211a沿中间基础孔4211b的周向Y分布设置，因此贯通孔4211的形状与圆形孔的形状不同。本申请通过将贯通孔4211设置为外侧辅助孔4211a和中间基础孔4211b的方式，使得在限定区域42a内可以相对地增大第一连接金属层4221和柔性介电层421的接触面积，从而有利于提高第一连接金属层4221和柔性介电层421 之间的结合力。因此，本申请实施例的第一连接金属层4221与柔性介电层421之间的结合力大于贯通孔4211为圆形孔时第一连接金属层4221与柔性介电层421之间的结合力，从而柔性介电层421和第一连接金属层之间的连接处可以承载更大的拉伸力。本申请实施例的柔性电路板42与印制电路板41相连，并且柔性介电层421在装配过程中受到拉伸力作用时，柔性介电层421和第一连接金属层4221不易发生分离，从而有利于降低柔性介电层421和第一连接金属层4221脱离连接而出现撕裂情况的可能性。
参见图13所示，第一连接金属层4221的中间通道4221a的横截面形状与贯通孔4211的横截面形状相同。在一些示例中，第一连接金属层4221均匀地设置于贯通孔4211的内壁，从而沿垂直于内壁的方向，第一连接金属层4221各个位置的厚度相等。
图14示意性地显示了一实施例的柔性介电层421的局部结构。参见图14和图15所示，柔性电路板42包括多排贯通孔4211。每排贯通孔4211中，相邻两个贯通孔4211之间的预定间距L指的是相邻两个中间基础孔4211b的轴线bb之间的垂直距离。
对于一个贯通孔4211，两个以上的外侧辅助孔4211a沿中间基础孔4211b的周向Y均匀分布，从而可以保证贯通孔4211的整体形状规整，有利于提高贯通孔4211的内壁和第一连接金属层4221之间连接区域的受力均衡性，保证贯通孔4211的内壁和第一连接金属层4221之间连接稳定性。本申请实施例的外侧辅助孔4211a的轴线aa与中间基础孔4211b的轴线bb间隔设置。外侧辅助孔4211a和中间基础孔4211b各自的轴线相互平行，从而外侧辅助孔4211a和中间基础孔4211b的延伸方向相同，易于加工制造。示例性地，外侧辅助孔4211a和中间基础孔4211b均为直通孔。
在一些示例中，外侧辅助孔4211a和中间基础孔4211b均为圆形孔，从而易于采用激光烧蚀或机械钻孔的方式加工制造，降低因贯通孔4211自身形状不规整而使得加工制造难度大，导致柔性介电层421的良品率偏低的可能性。两个以上的外侧辅助孔4211a沿中间基础孔4211b的周向Y均匀分布时，两个以上的外侧辅助孔4211a的轴线位于同一圆形轨迹上。该圆形轨迹的轴线与中间基础孔4211b的轴线重合。
参见图15所示，两个外侧辅助孔4211a沿中间基础孔4211b的周向Y分布。贯通孔4211的加工过程可以是预先在柔性介电层421上加工形成中间基础孔4211b，然后以中间基础孔4211b为基础，加工形成外侧辅助孔4211a。由于外侧辅助孔4211a和中间基础孔4211b存在相交区域，因此加工形成外侧辅助孔4211a时，会去除至少部分的中间基础孔4211b的内壁，从而观察完成加工的贯通孔4211时，中间基础孔4211b和外侧辅助孔4211a各自的内壁均在交点连线处断开不连续。示例性地，两个外侧辅助孔4211a沿中间基础孔4211b的周向Y均匀分布。中间基础孔4211b位于两个外侧辅助孔4211a之间。两个外侧辅助孔4211a和中间基础孔4211b各自的轴线均位于同一平面内。两个外侧辅助孔4211a和中间基础孔4211b的排列方向可以与每排贯通孔4211的排列方向相垂直。
两个外侧辅助孔4211a的正投影和中间基础孔4211b的正投影之间相交形成有交点P1、交点P2、交点P3和交点P4。中间基础孔4211b的轴线位于交点P1、交点P2、交点P3和交点P4的连线所限定的区域内侧，而外侧辅助孔4211a的轴线位于交点P1、交点P2、交点P3和交点P4的连线所限定的区域外侧。交点P1、交点P2、交点P3和交点P4的连线所限定的区域呈四边形，例如梯形或矩形。一个外侧辅助孔4211a 的正投影和中间基础孔4211b的正投影之间具有两个交点，分别是交点P1和交点P2。另一个外侧辅助孔4211a的正投影和中间基础孔4211b的正投影之间具有两个交点，分别是交点P3和交点P4。一个外侧辅助孔4211a的轴线aa和中间基础孔4211b的轴线bb分别位于交点P1和交点P2的连线的两侧。另一个外侧辅助孔4211a的轴线aa和中间基础孔4211b的轴线bb分别位于交点P3和交点P4的连线的两侧。交点P1和交点P2连线的长度可以小于外侧辅助孔4211a和中间基础孔4211b任一者的直径，而交点P3和交点P4连线的长度也可以小于外侧辅助孔4211a和中间基础孔4211b任一者的直径。
由于外侧辅助孔4211a和中间基础孔4211b相连通，因此外侧辅助孔4211a和中间基础孔4211b各自的内壁在交点P1和交点P2之间以及交点P3和交点P4之间的区域断开不连续。
交点P1和交点P3的连线以及交点P2和交点P4的连线相交并且夹角α范围为15°至135°。示例性地，交点P1和交点P3的连线以及交点P2和交点P4的连线相交并且夹角α范围为30°至90°。例如，夹角α可以但不限于为30°、45°、50°、60°、70°、80°、90°。
示例性地，参见图15所示，两个外侧辅助孔4211a的直径相同。外侧辅助孔4211a的直径和中间基础孔4211b的直径相同。本示例中，为了便于描述，外侧辅助孔4211a和中间基础孔4211b形成的贯通孔4211称为第一类型孔。两个外侧辅助孔4211a可以相对于中间基础孔4211b的轴线对称设置，从而有利于一个外侧辅助孔4211a的内壁与第一连接金属层4221之间的结合力以及另一个外侧辅助孔4211a的内壁与第一连接金属层4221之间的结合力保持均衡。中间基础孔4211b的直径取值范围可以是0.05毫米至0.5毫米，例如，可以但不限于是0.12毫米。外侧辅助孔4211a的轴线aa和中间基础孔4211b的轴线bb之间的垂直距离大于中间基础孔4211b的半径。需要说明的是，本实施例中，外侧辅助孔4211a的直径指的是K1和K2之间的连线长度。中间基础孔4211b的直径指的是交点P1和交点P3之间的连线长度或者交点P2和交点P4之间的连线长度。
本实施例中，中间基础孔4211b的一部分位于交点P1和交点P4连线远离中间基础孔4211b的轴线bb的一侧，并且中间基础孔4211b的一部分位于交点P2和交点P3连线远离中间基础孔4211b的轴线bb的一侧。
本申请的贯通孔4211可以为直孔。贯通孔4211的深度方向与柔性介电层421的厚度方向X相同。贯通孔4211为直孔的方式，也易于采用激光烧蚀或机械钻孔的方式加工制造。
图16示意性地显示了一实施例的柔性介电层421的局部结构。参见图16和图17所示，本实施例中的贯通孔4211与图15所示实施例的贯通孔4211相同部分不再赘述，这里主要描述不同之处。本实施例中，两个外侧辅助孔4211a的直径均小于中间基础孔4211b的直径。为了便于描述，本实施例中的外侧辅助孔4211a和中间基础孔4211b形成的贯通孔4211称为第二类型孔。示例性地，一个外侧辅助孔4211a的直径小于0.85倍的中间基础孔4211b的直径，而另一个外侧辅助孔4211a的直径小于1倍的中间基础孔4211b的直径。两个外侧辅助孔4211a的直径可以相同，例如，两个外侧辅 助孔4211a的直径均等于0.8倍的中间基础孔4211b的直径。中间基础孔4211b的直径的取值范围是0.05毫米至0.5毫米。例如，中间基础孔4211b的直径可以但不限于是0.12毫米。
在一些示例中，在贯通孔4211内设置第一连接金属层4221。第一连接金属层4221的中间通道4221a的横截面形状与贯通孔4211的横截面形状相同。在一些示例中，第一连接金属层4221均匀地设置于贯通孔4211的内壁，从而沿垂直于内壁的方向，第一连接金属层4221各个位置的厚度相等。
图18示意性地显示了一实施例的柔性介电层421的局部结构。参见图18所示，本实施例中的贯通孔4211与图15所示实施例的贯通孔4211相同部分不再赘述，这里主要描述不同之处。本实施例中，两个外侧辅助孔4211a的直径均大于中间基础孔4211b的直径。为了便于描述，本实施例中的外侧辅助孔4211a和中间基础孔4211b形成的贯通孔4211称为第三类型孔。示例性地，一个外侧辅助孔4211a的直径大于1.1倍的中间基础孔4211b的直径，而另一个外侧辅助孔4211a的直径大于或等于1倍的中间基础孔4211b的直径。例如，两个外侧辅助孔4211a的直径均等于1.3倍的中间基础孔4211b的直径。
图19示意性地显示了一实施例的柔性介电层421的局部结构。参见图19和图20所示，外侧辅助孔4211a和中间基础孔4211b均可以为正方形孔。外侧辅助孔4211a的孔径小于中间基础孔4211b的孔径。外侧辅助孔4211a的数量为两个。一个外侧辅助孔4211a的轴线aa可以与交点P1和交点P2的连线相交，而另一个外侧辅助孔4211a的轴线aa可以与交点P3和交点P4的连线相交。为了便于描述，本实施例中的外侧辅助孔4211a和中间基础孔4211b形成的贯通孔4211称为第四类型孔。
在一些示例中，在贯通孔4211内设置第一连接金属层4221。第一连接金属层4221的中间通道4221a的横截面形状与贯通孔4211的横截面形状相同。在一些示例中，第一连接金属层4221均匀地设置于贯通孔4211的内壁，从而沿垂直于内壁的方向，第一连接金属层4221各个位置的厚度相等。
图21示意性地显示了一实施例的柔性介电层421的局部结构。参见图21所示，本实施例中，三个外侧辅助孔4211a沿中间基础孔4211b的周向Y分布设置。为了便于描述，本实施例中的外侧辅助孔4211a和中间基础孔4211b形成的贯通孔4211称为第五类型孔。在限定区域42a，三个外侧辅助孔4211a和一个中间基础孔4211b形成的贯通孔4211的内壁面积相对更大，从而可以增大第一连接金属层4221与贯通孔4211的内壁的接触面积，有利于进一步提高第一连接金属层4221与贯通孔4211的内壁的结合力。各个外侧辅助孔4211a的正投影和中间基础孔4211b的正投影之间相交形成有交点P1、交点P2和交点P3。中间基础孔4211b的轴线位于交点P1、交点P2和交点P3的连线所限定的区域内侧，而外侧辅助孔4211a的轴线位于交点P1、交点P2和交点P3的连线所限定的区域外侧。交点P1、交点P2和交点P3的连线所限定的区域呈三角形。示例性地，交点P1和交点P2的连线以及交点P2和交点P3的连线之间的夹角β范围为15°至90°。例如，夹角β可以但不限于是30°、45°、50°、60°、70°、80°、90°。三个外侧辅助孔4211a可以相切设置，而交点P1、交点P2和交点P3分别为切点。
示例性地，三个外侧辅助孔4211a沿中间基础孔4211b的周向Y均匀分布设置，从而第一连接金属层4221与贯通孔4211的内壁相连后，有利于保证第一连接金属层4221与贯通孔4211的内壁在不同区域的结合力的均衡性。三个外侧辅助孔4211a各自的直径可以相同。外侧辅助孔4211a的直径大于中间基础孔4211b的直径。例如，三个外侧辅助孔4211a的直径均等于1.3倍的中间基础孔4211b的直径。
在其他一些示例中，一个外侧辅助孔4211a的直径大于1.1倍的中间基础孔4211b的直径。另一个外侧辅助孔4211a的直径大于或等于1倍的中间基础孔4211b的直径。另一个外侧辅助孔4211a的直径大于或等于1.1倍的中间基础孔4211b的直径。
在一些示例中，在贯通孔4211内设置第一连接金属层4221。第一连接金属层4221的中间通道4221a的横截面形状与贯通孔4211的横截面形状相同。在一些示例中，第一连接金属层4221均匀地设置于贯通孔4211的内壁，从而沿垂直于内壁的方向，第一连接金属层4221各个位置的厚度相等。
图22示意性地显示了一实施例的柔性介电层421的局部结构。参见图22所示，本实施例中的贯通孔4211与图21所示实施例的贯通孔4211相同部分不再赘述，这里主要描述不同之处。三个外侧辅助孔4211a中，每个外侧辅助孔4211a与中间基础孔4211b有两个交点。为了便于描述，本实施例中的外侧辅助孔4211a和中间基础孔4211b形成的贯通孔4211称为第六类型孔。从每个外侧辅助孔4211a与中间基础孔4211b的两个交点中选出一个交点，形成三个交点，分别为交点P1、交点P2和交点P3。交点P1、交点P2和交点P3间隔设置，而相邻两者之间中具有一个交点。交点P1、交点P2和交点P3的连线所限定的区域呈三角形。示例性地，交点P1和交点P2的连线以及交点P2和交点P3的连线之间的夹角β范围为15°至90°。例如，夹角可以但不限于是30°、45°、50°、60°、70°、80°、90°。
示例性地，外侧辅助孔4211a的直径可以大于中间基础孔4211b的直径。三个外侧辅助孔4211a各自的直径可以相同。例如，三个外侧辅助孔4211a的直径均等于1.3倍的中间基础孔4211b的直径。
在其他一些示例中，一个外侧辅助孔4211a的直径大于1.1倍的中间基础孔4211b的直径。另一个外侧辅助孔4211a的直径大于或等于1倍的中间基础孔4211b的直径。另一个外侧辅助孔4211a的直径大于或等于1.1倍的中间基础孔4211b的直径。
在其他一些示例中，外侧辅助孔4211a的直径可以小于中间基础孔4211b的直径。各个外侧辅助孔4211a的直径相等，而外侧辅助孔4211a的直径是中间基础孔4211b的直径的0.8倍。
在一些示例中，在贯通孔4211内设置第一连接金属层4221。第一连接金属层4221的中间通道4221a的横截面形状与贯通孔4211的横截面形状相同。在一些示例中，第一连接金属层4221均匀地设置于贯通孔4211的内壁，从而沿垂直于内壁的方向，第一连接金属层4221各个位置的厚度相等。
图23示意性地显示了一实施例的柔性介电层421的局部结构。参见图23所示，本实施例中，四个外侧辅助孔4211a沿中间基础孔4211b的周向Y分布设置。为了便于描述，本实施例中的外侧辅助孔4211a和中间基础孔4211b形成的贯通孔4211称为第七类型孔。在限定区域42a，四个外侧辅助孔4211a和一个中间基础孔4211b形成 的贯通孔4211的内壁面积相对更大，从而进一步增大第一连接金属层4221与贯通孔4211的内壁的接触面积，有利于进一步提高第一连接金属层4221与贯通孔4211的内壁的结合力。各个外侧辅助孔4211a的正投影和中间基础孔4211b的正投影之间相交形成有交点P1、交点P2、交点P3和交点P4。交点P1、交点P2、交点P3和交点P4的连线所限定的区域呈四边形，例如梯形或矩形。交点P1和交点P3的连线以及交点P2和交点P4的连线相交并且夹角α范围可以为15°至135°。示例性地，交点P1和交点P3的连线以及交点P2和交点P4的连线相交并且夹角α范围为30°至90°。例如，夹角α可以但不限于为30°、45°、50°、60°、70°、80°、90°。四个外侧辅助孔4211a可以相切设置，而交点P1、交点P2、交点P3和交点P4分别为切点。
示例性地，四个外侧辅助孔4211a沿中间基础孔4211b的周向Y均匀分布设置，从而第一连接金属层4221与贯通孔4211的内壁相连后，有利于保证第一连接金属层4221与贯通孔4211的内壁在不同区域的结合力的均衡性。外侧辅助孔4211a的直径等于中间基础孔4211b的直径。四个外侧辅助孔4211a各自的直径相同。
在其他一些示例中，一个外侧辅助孔4211a的直径大于1.1倍的中间基础孔4211b的直径。另一个外侧辅助孔4211a的直径大于或等于1倍的中间基础孔4211b的直径。其余两个外侧辅助孔4211a的直径大于或等于1.1倍的中间基础孔4211b的直径。
在一些示例中，在贯通孔4211内设置第一连接金属层4221。第一连接金属层4221的中间通道4221a的横截面形状与贯通孔4211的横截面形状相同。在一些示例中，第一连接金属层4221均匀地设置于贯通孔4211的内壁，从而沿垂直于内壁的方向，第一连接金属层4221各个位置的厚度相等。
图24示意性地显示了一实施例的柔性介电层421的局部结构。参见图24所示，本实施例中的贯通孔4211与图23所示实施例的贯通孔4211相同部分不再赘述，这里主要描述不同之处。本实施例中，四个外侧辅助孔4211a沿中间基础孔4211b的周向Y分布设置。每个外侧辅助孔4211a与中间基础孔4211b有两个交点。为了便于描述，本实施例中的外侧辅助孔4211a和中间基础孔4211b形成的贯通孔4211称为第八类型孔。从每个外侧辅助孔4211a与中间基础孔4211b的两个交点中选出一个交点，四个交点分别为交点P1、交点P2、交点P3和交点P4。交点P1、交点P2、交点P3和交点P4间隔设置，而相邻两者之间中具有一个交点。交点P1、交点P2、交点P3和交点P4的连线所限定的区域呈四边形，例如梯形或矩形。
示例性地，四个外侧辅助孔4211a沿中间基础孔4211b的周向Y均匀分布设置。四个外侧辅助孔4211a相互间隔设置。外侧辅助孔4211a的直径大于中间基础孔4211b的直径。四个外侧辅助孔4211a各自的直径相同。例如，四个外侧辅助孔4211a的直径均等于1.3倍的中间基础孔4211b的直径。
在其他一些示例中，一个外侧辅助孔4211a的直径大于1.1倍的中间基础孔4211b的直径。另一个外侧辅助孔4211a的直径大于或等于1倍的中间基础孔4211b的直径。其余两个外侧辅助孔4211a的直径大于或等于1.1倍的中间基础孔4211b的直径。
在其他一些示例中，外侧辅助孔4211a的直径可以小于中间基础孔4211b的直径。各个外侧辅助孔4211a的直径相等，而外侧辅助孔4211a的直径是中间基础孔4211b的直径的0.8倍。
在一些示例中，在贯通孔4211内设置第一连接金属层4221。第一连接金属层4221的中间通道4221a的横截面形状与贯通孔4211的横截面形状相同。在一些示例中，第一连接金属层4221均匀地设置于贯通孔4211的内壁，从而沿垂直于内壁的方向，第一连接金属层4221各个位置的厚度相等。
图25示意性地显示了一实施例的柔性电路板42的局部剖视结构。参见图25所示，第一连接金属层4221的中间通道4221a的横截面形状与贯通孔4211的横截面形状相同。在一些示例中，第一连接金属层4221均匀地设置于贯通孔4211的内壁，从而沿垂直于内壁的方向，第一连接金属层4221各个位置的厚度相等。第一连接金属层4221的中间通道4221a的中心与贯通孔4211的中心相重合，从而便于通过中间通道4221a的中心与印制电路板41上的焊盘411的中心对准定位，以保证焊接引脚422和焊盘411相对位置满足位置精度要求。
图26示意性地显示了一实施例的柔性电路板42的局部剖视结构。参见图26所示，柔性电路板42的焊接引脚422还包括第二连接金属层4222和第三连接金属层4223。沿厚度方向，第二连接金属层4222和第三连接金属层4223分别设置于柔性介电层421的两侧。第二连接金属层4222和第三连接金属层4223分别与第一连接金属层4221相连。第二连接金属层4222包括与中间通道4221a相连通的第一通孔4222a。第三连接金属层4223包括与中间通道4221a相连通的第二通孔4223a。第二连接金属层4222用于与金属走线423相连。示例性地，第二连接金属层4222与限定区域42a形状相同。第二连接金属层4222的边缘可以与限定区域42a的边界对齐。熔化的焊膏70从柔性介电层421背向焊盘411的一侧溢出后，焊膏70会流动到第二连接金属层4222背向焊盘411的表面。焊膏70固化后，与第二连接金属层4222实现连接。第三连接金属层4223用于面向印制电路板41的焊盘411并与焊盘411焊接。第二连接金属层4222和第三连接金属层4223分别与柔性介电层421相连，从而有利于进一步提高柔性介电层421和焊接引脚422之间的结合力。第二连接金属层4222的第一通孔4222a的形状以及第三连接金属层4223的第二通孔4223a分别与第一连接金属层4221的中间通道4221a的形状相同。示例性地，第二连接金属层4222为圆形结构或矩形结构。第三连接金属层4223为圆形结构或矩形结构。示例性地，采用化学镀的方式形成第二连接金属层4222和第三连接金属层4223。
参见图26所示，柔性介电层421包括两层绝缘基层421a。贯通孔4211贯穿两层绝缘基层421a。柔性电路板42的焊接引脚422还包括第四连接金属层。第四连接金属层与第一连接金属层4221相连，并且第四连接金属层设置于两层绝缘基层421a之间。第四连接金属层与柔性介电层421相连，从而有利于进一步提高柔性介电层421和焊接引脚422之间的结合力。示例性地，第一连接金属层4221、第二连接金属层4222、第三连接金属层4223以及第四连接金属层为一体成型结构。
图27示意性地显示了一实施例的柔性电路板42和印制电路板41连接状态的局部剖视结构。参见图27所示，熔化后的焊膏70固化后形成焊点80。焊点80包括第一连接部81、连接柱82和第二连接部83。第一连接部81位于焊盘411和柔性介电层421之间。第一连接部81遮挡中间通道4221a面向印制电路板41的开口。第二连接部83位于柔性介电层421背向印制电路板41的一侧。第二连接部83遮挡中间通道 4221a背向印制电路板41的开口。连接柱82位于中间通道4221a内。第一连接部81和第二连接部83分别连接于连接柱82。第一连接部81与第三连接金属层4223面向焊盘411的表面相连。第二连接部83与第二连接金属层4222相连。
参见图28和图29所示，基于本申请实施例，表1示例性地表示了相关技术中第一连接金属层4221的中间通道4221a为圆形孔，以及本申请实施例的第一连接金属层4221的中间通道4221a为第一类型孔、第二类型孔和第七类型孔的数据。
表1
Figure PCTCN2022113314-appb-000001
表1中的参数H表示沿中间通道4221a的轴向，测量得到的中间通道4221a的深度。中间通道4221a的轴向与柔性介电层421的厚度方向X相同。表1中，圆形孔的深度H、第一类型孔的深度H、第二类型孔的深度H以及第七类型孔的深度H取值相同。
在第二连接金属层4222的宽度和长度尺寸相同的情况下，第一连接金属层4221的中间通道4221a的形状不同会使得中间通道4221a的孔壁面积大小不同。示例性地，参见表1和图30所示，中间通道4221a的形状为圆形孔时，中间通道4221a的孔壁面积为S1。中间通道4221a的形状为第一类型孔、第二类型孔和第七类型孔的实施例中，中间通道4221a的孔壁面积分别为S2、S3和S4。其中，S3＞S4＞S2＞S1。
第一连接金属层4221的中间通道4221a的横截面形状与贯通孔4211的横截面形 状相同。中间通道4221a的孔壁面积的大小与第一连接金属层4221和柔性介电层421的接触面积的大小正相关，因此本申请通过将贯通孔4211设置为外侧辅助孔4211a和中间基础孔4211b的方式，可以相对地增大第一连接金属层4221和柔性介电层421的接触面积，从而有利于提高第一连接金属层4221和柔性介电层421之间的结合力。
在本申请实施例的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应作广义理解，例如，可以是固定连接，也可以是通过中间媒介间接相连，可以是两个元件内部的连通或者两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请实施例中的具体含义。
在本申请实施例或者暗示所指的装置或者元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请实施例的限制。在本申请实施例的描述中，“多个”的含义是两个或两个以上，除非是另有精确具体地规定。
本申请实施例的说明书和权利要求书及上述附图中的术语“第一”、“第二”、“第三”、“第四”等(如果存在)是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的数据在适当情况下可以互换，以便这里描述的本申请实施例的实施例例如能够以除了在这里图示或描述的那些以外的顺序实施。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它步骤或单元。
本文中的术语“多个”是指两个或两个以上。本文中术语“和/或”，仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系；在公式中，字符“/”，表示前后关联对象是一种“相除”的关系。
可以理解的是，在本申请的实施例中涉及的各种数字编号仅为描述方便进行的区分，并不用来限制本申请的实施例的范围。
可以理解的是，在本申请的实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请的实施例的实施过程构成任何限定。

Claims (18)

  1. 一种柔性电路板，其特征在于，至少包括：
    柔性介电层，包括沿所述柔性介电层的厚度方向延伸的贯通孔，所述贯通孔包括中间基础孔和外侧辅助孔，两个以上的所述外侧辅助孔沿所述中间基础孔的周向分布设置，所述中间基础孔连通两个以上的所述外侧辅助孔；
    第一连接金属层，设置于所述贯通孔的内壁并且与所述柔性介电层相连，所述第一连接金属层包括沿所述厚度方向延伸的中间通道。
  2. 根据权利要求1所述的柔性电路板，其特征在于，沿所述中间基础孔的周向，两个以上的所述外侧辅助孔均匀分布。
  3. 根据权利要求1或2所述的柔性电路板，其特征在于，所述外侧辅助孔的轴线与所述中间基础孔的轴线相互平行。
  4. 根据权利要求1至3任一项所述的柔性电路板，其特征在于，所述中间基础孔和所述外侧辅助孔均为圆形孔。
  5. 根据权利要求4所述的柔性电路板，其特征在于，沿所述厚度方向，各个所述外侧辅助孔的正投影和所述中间基础孔的正投影之间相交形成有交点P1、交点P2、交点P3和交点P4，所述中间基础孔的轴线位于所述交点P1、所述交点P2、所述交点P3和所述交点P4的连线所限定的区域内侧，所述外侧辅助孔的轴线位于所述交点P1、所述交点P2、所述交点P3和所述交点P4的连线所限定的区域外侧。
  6. 根据权利要求5所述的柔性电路板，其特征在于，所述交点P1和所述交点P3的连线以及所述交点P2和所述交点P4的连线相交并且夹角范围为15°至135°。
  7. 根据权利要求4至6任一项所述的柔性电路板，其特征在于，两个所述外侧辅助孔分别位于所述中间基础孔的两侧，所述外侧辅助孔与所述中间基础孔相连通，两个所述外侧辅助孔的轴线以及所述中间基础孔的轴线位于同一平面内；或者，四个所述外侧辅助孔环绕所述中间基础孔的轴线设置。
  8. 根据权利要求4所述的柔性电路板，其特征在于，沿所述厚度方向，各个所述外侧辅助孔的正投影和所述中间基础孔的正投影之间相交形成有交点P1、交点P2和交点P3，所述中间基础孔的轴线位于所述交点P1、所述交点P2和所述交点P3的连线所限定的区域内侧，所述外侧辅助孔的轴线位于所述交点P1、所述交点P2和所述交点P3的连线所限定的区域外侧。
  9. 根据权利要求8所述的柔性电路板，其特征在于，所述交点P1和所述交点P2的连线以及所述交点P2和所述交点P3的连线之间的夹角范围为15°至90°。
  10. 根据权利要求4、8或9所述的柔性电路板，其特征在于，三个所述外侧辅助孔环绕所述中间基础孔的轴线设置。
  11. 根据权利要求4至10任一项所述的柔性电路板，其特征在于，所述外侧辅助孔的直径大于所述中间基础孔的直径。
  12. 根据权利要求11所述的柔性电路板，其特征在于，各个所述外侧辅助孔的直径相等，所述外侧辅助孔的直径是所述中间基础孔的直径的1.3倍。
  13. 根据权利要求4至10任一项所述的柔性电路板，其特征在于，所述外侧辅助孔的直径小于所述中间基础孔的直径。
  14. 根据权利要求13所述的柔性电路板，其特征在于，各个所述外侧辅助孔的直径相等，所述外侧辅助孔的直径是所述中间基础孔的直径的0.8倍。
  15. 根据权利要求1至14任一项所述的柔性电路板，其特征在于，所述柔性电路板还包括第二连接金属层和第三连接金属层，沿所述厚度方向，所述第二连接金属层 和所述第三连接金属层分别设置于所述柔性介电层的两侧，所述第二连接金属层和所述第三连接金属层分别与所述第一连接金属层相连，所述第二连接金属层包括与所述中间通道相连通的第一通孔，所述第三连接金属层包括与所述中间通道相连通的第二通孔。
  16. 根据权利要求15所述的柔性电路板，其特征在于，所述柔性介电层包括两层绝缘基层，所述贯通孔贯穿两层所述绝缘基层，所述柔性电路板还包括第四连接金属层，所述第四连接金属层与所述第一连接金属层相连，并且所述第四连接金属层设置于两层所述绝缘基层之间。
  17. 一种电路板组件，其特征在于，至少包括：
    印制电路板，包括焊盘；
    如权利要求1至16任一项所述的柔性电路板，所述焊盘和所述第一连接金属层通过焊点焊接，所述焊点的一部分填充于所述中间通道内。
  18. 一种电子设备，其特征在于，至少包括如权利要求17所述的电路板组件。
PCT/CN2022/113314 2021-09-27 2022-08-18 柔性电路板、电路板组件以及电子设备 WO2023045640A1 (zh)

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