Terminal device

Abstract

Embodiments of the present application provide a terminal device, divided into at least two folding areas and a rotating shaft area located between the two adjacent folding areas. The terminal device comprises a plurality of circuit boards and a flexible circuit board, each folding area is provided with at least one circuit board, and the flexible circuit board passes through the rotating shaft area and is connected to at least two circuit boards. Connecting the flexible circuit board to the circuit boards by means of laser welding increases the distance between a user and a heat source during charging, thereby lowering the temperature perceived by the user; reduces the number of interconnections, thereby reducing heat generated during charging; and facilitates the disassembly of the flexible circuit board.

Description

terminal device

[0001] Cross-reference to related applications

[0002] This application, filed on July 22, 2024, with application number 202410985650.X and title "Terminal Device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of terminal technology, and in particular to a terminal device. Background Technology

[0004] Foldable devices such as foldable screen phones offer advantages such as a better viewing experience and a wider field of view, making them increasingly popular with users. However, these devices generate a significant amount of heat during charging, and as users demand thinner and lighter devices, this heat will become more noticeable, impacting the user experience. Summary of the Invention

[0005] In view of this, it is necessary to provide a terminal device that can reduce the user's temperature perception during charging, in order to solve the above-mentioned technical problems.

[0006] In a first aspect, embodiments of this application provide a terminal device divided into at least two folding areas and a hinge area located between two adjacent folding areas. The terminal device includes multiple circuit boards, a flexible circuit board, a conductor, a screen, and multiple batteries. Each folding area is provided with at least one circuit board; the flexible circuit board passes through the hinge area and connects at least two of the multiple circuit boards; the conductor connects the flexible circuit board and the circuit board, and the conductor is formed by laser welding; the area where the flexible circuit board is electrically connected to the circuit board is located on the side of the circuit board opposite to the screen; each folding area is provided with a battery, and the battery is electrically connected to the circuit board located in the same folding area.

[0007] In the above structural design, the flexible circuit board is connected to the circuit board via laser welding. This reduces the thickness of the electrical connection area, effectively increasing the distance between the electrical connection area and the outer surface of the terminal device. In other words, during charging, it increases the distance between the user and the heat source, helping to reduce the temperature perceived by the user. Furthermore, using laser welding for direct electrical connection reduces the number of connection steps, shortens the current flow path, and reduces resistance, thereby reducing the heat generated during charging and further reducing the temperature perceived by the user. Using laser welding instead of BTB connections results in a thinner flexible circuit board, facilitating its disassembly and reducing the number of components removed, thus minimizing the risk of component damage.

[0008] In one possible implementation, the terminal device is divided into a first folding area, a first pivot area, and a second folding area connected in sequence, and a plurality of circuit boards including a first circuit board and a second circuit board; the first circuit board is located in the first folding area, and the second circuit board is located in the second folding area; a flexible circuit board passes through the first pivot area and is electrically connected to the first circuit board and the second circuit board; the flexible circuit board is electrically connected to the first circuit board after laser welding, and / or the flexible circuit board is electrically connected to the second circuit board after laser welding.

[0009] The above structural design is one possible implementation of a two-fold terminal device. The two folded areas are electrically connected by laser welding using a flexible circuit board. This increases the distance between the user and the heat source during charging, which helps to reduce the temperature felt by the user; it also helps to reduce the number of switching operations and the heat generated during charging; and it facilitates the disassembly of the flexible circuit board.

[0010] In one possible implementation, the terminal device is divided into a first folding area, a first hinge area, a second folding area, a second hinge area, and a third folding area connected in sequence. Multiple circuit boards include a first circuit board, a second circuit board, and a third circuit board. The first circuit board is located in the first folding area, the second circuit board is located in the second folding area, and the third circuit board is located in the third folding area. A flexible circuit board passes through the first hinge area, the second folding area, and the second hinge area and is electrically connected to the first circuit board, the second circuit board, and the third circuit board. The flexible circuit board is electrically connected to the first circuit board after laser welding, and / or the flexible circuit board is electrically connected to the second circuit board after laser welding, and / or the flexible circuit board is electrically connected to the third circuit board after laser welding.

[0011] The above structural design is a possible implementation of a three-fold terminal device. The flexible circuit board can pass through multiple pivot areas, which is beneficial to improving the quality of radio frequency signals; it is also beneficial to reduce the number of BTBs, thereby increasing the circuit layout area of ​​the flexible circuit board; using the flexible circuit board to achieve electrical connection between the two folded areas through laser welding can increase the distance between the user and the heat source during charging, which is beneficial to reducing the temperature felt by the user; it is beneficial to reduce the number of switching times and reduce the heat generated during charging; and it is beneficial to disassemble the flexible circuit board.

[0012] In one possible implementation, the terminal device is divided into a first folding area, a first hinge area, a second folding area, a second hinge area, a third folding area, a third hinge area, and a fourth folding area connected in sequence. Multiple circuit boards include a first circuit board, a second circuit board, a third circuit board, and a fourth circuit board. The first circuit board is located in the first folding area, the second circuit board is located in the second folding area, the third circuit board is located in the third folding area, and the fourth circuit board is located in the fourth folding area. A flexible circuit board passes through the first hinge area, the second folding area, the second hinge area, the third folding area, and the third hinge area and is electrically connected to the first circuit board, the second circuit board, the third circuit board, and the fourth circuit board. The flexible circuit board is electrically connected to the first circuit board after laser welding, and / or the flexible circuit board is electrically connected to the second circuit board after laser welding, and / or the flexible circuit board is electrically connected to the third circuit board after laser welding, and / or the flexible circuit board is electrically connected to the fourth circuit board after laser welding.

[0013] The above structural design is a possible implementation of a four-fold terminal device. The flexible circuit board can pass through multiple pivot areas, which is beneficial to improving the quality of radio frequency signals and reducing the number of BTBs, thereby increasing the circuit layout area of ​​the flexible circuit board.

[0014] In one possible implementation, the flexible circuit board includes a first body and a first pad. The first pad includes a through portion and an extension portion. The through portion passes through the first body and forms a first through hole. The extension portion is located at both ends of the through portion and is located on the surface of the first body. The first circuit board includes a second body and a second pad. The second pad is located on the surface of the second body. A conductor is located in the first through hole and is connected to the first pad and the second pad.

[0015] In the above structural design, the electrical connection is achieved by the conductor formed after laser welding, which is beneficial to reducing the thickness of the electrical connection area; and it is also beneficial to form an "I"-shaped conductor, which is beneficial to improving the welding strength.

[0016] In one possible implementation, the flexible circuit board includes a first body and a first pad, the first pad penetrating the first body and forming a first through hole; the first circuit board includes a second body and a second pad, the second pad penetrating the second body and forming a second through hole; a conductor is housed in the first through hole and the second through hole, and is also located between the first body and the second body.

[0017] In the above structural design, the electrical connection is achieved by the conductor formed after laser welding, which is beneficial to reducing the thickness of the electrical connection area; and it is also beneficial to form a cross-shaped conductor, which is beneficial to improving the welding strength.

[0018] In one possible implementation, the terminal device further includes a system-on-a-chip (SoC) and a charging chip, which are disposed on the same circuit board.

[0019] The above structural design is one possible implementation of the terminal device structural design.

[0020] In one possible implementation, adhesive areas are provided at both ends of the flexible circuit board, which serve to bond the circuit board during disassembly or assembly.

[0021] In the above structural design, an adhesive area is provided at the end of the flexible circuit board. The adhesive area is used to cooperate with the first traction piece and the second traction piece, thereby playing an adhesive role in the steps of disassembling or assembling the flexible circuit board, reducing the risk of component damage caused by the need to remove or assemble too many components.

[0022] In one possible implementation, the flexible circuit board includes a cavity, and the flexible circuit board is bent in the region of the cavity.

[0023] In the above structural design, the cavity facilitates the bending of the flexible circuit board.

[0024] Secondly, embodiments of this application provide a terminal device divided into at least two folding areas and a hinge area located between two adjacent folding areas. The terminal device includes multiple circuit boards, conductors, and a charging chip. Each folding area is provided with at least one circuit board. At least one of the multiple circuit boards is a rigid-flex board, which includes a rigid part and a flexible part. The rigid part is located in the folding area, and the flexible part passes through the hinge area. The conductor connects the flexible part and the circuit boards other than the rigid-flex board. The conductor is formed by laser welding. Each folding area is provided with a battery, and the battery is electrically connected to the circuit board located in the same folding area.

[0025] In the above structural design, the flexible circuit board is connected to the circuit board via laser welding. This reduces the thickness of the electrical connection area, effectively increasing the distance between the electrical connection area and the outer surface of the terminal device. In other words, during charging, this increases the distance between the user and the heat source, helping to reduce the temperature perceived by the user. Furthermore, using laser welding for direct electrical connection reduces the number of transfers, shortens the current flow path, and reduces resistance, thereby reducing heat generated during charging and further reducing the temperature perceived by the user. Using laser welding instead of BTB connections results in a thinner flexible circuit board, facilitating its disassembly and reducing the number of components removed, thus minimizing the risk of component damage. The rigid-flex board is a single integrated structure, eliminating the need for additional electrical connection methods, further reducing one transfer and further minimizing heat generated during charging.

[0026] In one possible implementation, the terminal device is divided into a first folding area, a first pivot area, and a second folding area connected in sequence, and a plurality of circuit boards including a first circuit board and a second circuit board; the first circuit board is a rigid-flex board, with the rigid part located in the first folding area; the flexible part passes through the first pivot area and extends to the second folding area, and the second circuit board is located in the second folding area; the flexible part and the second circuit board are electrically connected after laser welding.

[0027] The above-described structural design is one possible implementation of a two-fold terminal device. The flexible board portion of the rigid-flex board is used to realize the electrical connection of multiple folding areas. The rigid-flex board is an integral structure, eliminating the need for additional electrical connection methods, which is equivalent to further reducing one transfer and further reducing the heat generated during charging.

[0028] In one possible implementation, the terminal device is divided into a first folding area, a first hinge area, and a second folding area connected in sequence. Multiple circuit boards include a first circuit board and a second circuit board. The first circuit board is located in the first folding area. The second circuit board is a rigid-flex board, with the rigid portion located in the second folding area and the flexible portion extending through the first hinge area and into the first folding area. The flexible portion is electrically connected to the first circuit board via laser welding. This structure is one possible implementation of a two-fold terminal device.

[0029] In one possible implementation, the multiple circuit boards further include a third circuit board located in the second folding area. The third circuit board is a rigid-flex board, with its flexible portion extending through the first pivot area and into the first folding area, and electrically connected to the first circuit board via laser welding. This structure is one possible implementation of a three-fold terminal device, where at least two circuit boards can be rigid-flex boards.

[0030] In one possible implementation, the terminal device is divided into a first folding area, a first hinge area, a second folding area, a second hinge area, and a third folding area connected sequentially. Multiple circuit boards include a first circuit board, a second circuit board, and a third circuit board. The first circuit board is a rigid-flex PCB, with the rigid portion located in the first folding area; the second circuit board is located in the second folding area; and the third circuit board is located in the third folding area. The flexible portion passes through the first hinge area, the second folding area, and the second hinge area, extending to the third folding area. The flexible portion and the second and third circuit boards are electrically connected by laser welding. In this structural design, the flexible portion can pass through multiple hinge areas, which is beneficial for improving RF signal quality and reducing the number of BTBs (Block Components), thereby increasing the circuit layout area of ​​the rigid-flex PCB.

[0031] In one possible implementation, the terminal device is divided into a first folding area, a first hinge area, a second folding area, a second hinge area, and a third folding area connected sequentially. Multiple circuit boards include a first circuit board, a second circuit board, and a third circuit board. The first circuit board is located in the first folding area, and the third circuit board is located in the third folding area. The second circuit board is a rigid-flex board, with the rigid portion located in the second folding area and the flexible portion passing through the first hinge area and extending into the first folding area to be electrically connected to the first circuit board. The flexible portion also passes through the second hinge area and extends into the third folding area to be electrically connected to the third circuit board. The flexible portion and the first circuit board are electrically connected after laser welding, and the flexible portion and the third circuit board are electrically connected after laser welding. This structure is one possible implementation of a three-fold terminal device. The flexible portion can pass through multiple hinge areas, which is beneficial for improving RF signal quality and reducing the number of BTBs (Browser-to-Board) circuit boards, thereby improving the circuit layout area of ​​the rigid-flex board.

[0032] In one possible implementation, the terminal device is divided into a first folding area, a first hinge area, a second folding area, a second hinge area, and a third folding area connected sequentially. Multiple circuit boards include a first circuit board, a second circuit board, and a third circuit board. The first circuit board is located in the first folding area, the second circuit board is located in the second folding area, and the third circuit board is a rigid-flex board. The rigid part is located in the third folding area, and the flexible part passes through the second hinge area, the second folding area, and the first hinge area, extending to the first folding area. The flexible part and the first circuit board are electrically connected by laser welding, and the flexible part and the second circuit board are electrically connected by laser welding. This structure is one possible implementation of a three-fold terminal device.

[0033] In one possible implementation, the terminal device is divided into a first folding area, a first hinge area, a second folding area, a second hinge area, and a third folding area connected in sequence. Multiple circuit boards include a first circuit board, a second circuit board, and a third circuit board. The first and third circuit boards are both rigid-flex boards. The second circuit board is located in the second folding area. The flexible portion of the first circuit board extends through the first hinge area to the second folding area and is electrically connected to the second circuit board. The flexible portion of the third circuit board extends through the second hinge area to the second folding area and is electrically connected to the flexible portion of the first circuit board. The flexible portions of the first and second circuit boards are electrically connected by laser welding, and the flexible portions of the third and first circuit boards are electrically connected by laser welding. This structure is one possible implementation of a three-fold terminal device.

[0034] In one possible implementation, the terminal device is divided into a first folding area, a first hinge area, a second folding area, a second hinge area, and a third folding area connected in sequence. Multiple circuit boards include a first circuit board, a second circuit board, and a third circuit board. The first circuit board is located in the first folding area. Both the second and third circuit boards are rigid-flex boards; the rigid portion of the second circuit board is located in the second folding area, and the rigid portion of the third circuit board is located in the third folding area. The flexible portion of the second circuit board passes through the first hinge area and extends into the first folding area, electrically connecting to the first circuit board. The flexible portion of the third circuit board passes through the second hinge area and extends into the second folding area, electrically connecting to the second circuit board. The flexible portion of the second circuit board and the first circuit board are electrically connected after laser welding, and the flexible portion of the third circuit board and the second circuit board are electrically connected after laser welding. This structure is one possible implementation of a three-fold terminal device.

[0035] In one possible implementation, the terminal device further includes a system-on-a-chip (SoC) and a charging chip, which are disposed on the same circuit board.

[0036] In one possible implementation, an adhesive area is provided at the end of the flexible board portion away from the rigid board portion, the adhesive area being used to perform an adhesive function during the disassembly or assembly of the flexible-rigid combination board.

[0037] In the above structural design, an adhesive area is provided at the end of the flexible plate portion of the rigid-flex plate. The adhesive area is used to cooperate with the first traction piece and the second traction piece, thereby playing an adhesive role in the steps of disassembling or assembling the rigid-flex plate, reducing the risk of component damage caused by the need to remove or assemble too many components.

[0038] In one possible implementation, the rigid-flex plate includes a cavity located in the flexible portion, and the rigid-flex plate is bent in the region of the cavity. In the above structural design, the cavity facilitates the bending of the rigid-flex plate. Attached Figure Description

[0039] Figure 1 is a schematic diagram of the internal component distribution of a terminal device provided by related technologies.

[0040] Figure 2 is a schematic diagram of the connection principle between the mobile phone charger and the mobile phone provided by the related technology.

[0041] Figure 3 is a schematic diagram of the connection principle of the mobile phone charger, radio frequency chip and battery provided by related technologies.

[0042] Figure 4 is a schematic diagram of the heat generation of a mobile phone during the charging process, provided by related technologies.

[0043] Figure 5 is a schematic diagram of the electrical connection structure of the board-to-board connector provided by related technologies.

[0044] Figure 6 is a schematic diagram of the structure of a terminal device provided in an embodiment of this application.

[0045] Figure 7 is a structural schematic diagram of the terminal device shown in Figure 6 from another direction.

[0046] Figure 8 is a schematic diagram of the internal component distribution of the terminal device provided in the embodiment of this application.

[0047] Figure 9 is a schematic diagram of the internal component distribution of the terminal device provided in the embodiment of this application from another position.

[0048] Figure 10 is a cross-sectional schematic diagram of the terminal device provided in the embodiment of this application in the unfolded state.

[0049] Figure 11 is a cross-sectional schematic diagram of the terminal device provided in the embodiment of this application in a folded state.

[0050] Figure 12 is a schematic diagram of the structure after the first circuit board and the flexible circuit board are connected according to an embodiment of this application.

[0051] Figure 13 is a cross-sectional schematic diagram of the first circuit board and the flexible circuit board connected by a conductor according to an embodiment of this application.

[0052] Figure 14 is a schematic diagram of the structure of the laser-welded first circuit board and the flexible circuit board provided in the embodiment of this application.

[0053] Figure 15 is a schematic diagram of the connection between the first circuit board and the flexible circuit board provided in some other embodiments of this application.

[0054] Figure 16 is a comparative schematic diagram showing the structure of the first circuit board and the flexible circuit board connected by board-to-board connectors and laser welding, respectively.

[0055] Figure 17 is a top view of the terminal device provided in an embodiment of this application.

[0056] Figure 18A is a cross-sectional schematic diagram of a portion of a terminal device according to some other embodiments.

[0057] Figure 18B is a cross-sectional schematic diagram of a portion of the terminal device shown in Figure 17 along direction II.

[0058] Figure 18C is a cross-sectional schematic diagram of a portion of a terminal device provided in some other embodiments of this application.

[0059] Figure 19 is a cross-sectional flowchart of bonding the first traction piece to a flexible circuit board according to an embodiment of this application.

[0060] Figure 20 is a top view schematic diagram of the process of bonding the first traction piece and the second traction piece on a flexible circuit board according to an embodiment of this application.

[0061] Figure 21 is a cross-sectional flowchart illustrating the process of disassembling a flexible circuit board from a terminal device using a first traction piece and a second traction piece according to an embodiment of this application.

[0062] Figure 22 is a cross-sectional flowchart of assembling a flexible circuit board into a terminal device using a first traction piece and a second traction piece according to an embodiment of this application.

[0063] Figure 23 is a cross-sectional schematic diagram of a flexible circuit board provided in some embodiments of this application.

[0064] Figure 24 is a cross-sectional schematic diagram of a flexible circuit board provided in some other embodiments of this application.

[0065] Figure 25A is a top view schematic diagram of a flexible circuit board provided in some embodiments of this application.

[0066] Figure 25B is a top view schematic diagram of a flexible circuit board provided in some embodiments of this application.

[0067] Figure 26 is a cross-sectional schematic diagram of a flexible circuit board provided in some embodiments of this application.

[0068] Figure 27A is a schematic diagram of the structure of the first pad of the flexible circuit board provided in the embodiment of this application.

[0069] Figure 27B is a schematic diagram of the structure of the first pad of a flexible circuit board provided in some other embodiments of this application.

[0070] Figure 28 is a schematic diagram of the connection of the line layer provided in the embodiment of this application.

[0071] Figures 29 to 39 are schematic diagrams showing the internal component distribution of a terminal device provided in other embodiments of this application.

[0072] Figure 40 is a cross-sectional schematic diagram of a rigid-flex plate provided in some embodiments of this application.

[0073] Figure 41 is a flowchart of the fabrication process for the rigid-flex PCB shown in Figure 40.

[0074] Explanation of main component symbols

[0075] Terminal devices: 100, 100', 100a, 100b, 100c, 100d, 100e, 100f, 100g, 100h, 100i, 100j, 100k; First folding area: 11, 11'; Second folding area: 12, 12'; Third folding area: 13; Fourth folding area: 14; First pivot area: 21, 21'; Second pivot area: 22; Third pivot area: 23; First circuit board: 31, 31', 31d, 31e, 31f, 31g, 31h, 31i, 31j, 31k; Female solder pad: 311'; Second body: 312; Second pad: 313; Second via: 314; Second circuit board: 32, 32', 32d, 32e, 32f, 32g, 32h, 32i, 32j, 32k; Third circuit board: 33, 33f, 33g, 33h, 33i, 33j, 33k; Fourth circuit board: 34; Flexible circuit board: 35, 35', 35a, 35b, 35c; Male solder pad: 351'; Adhesive layer: 352'; Reinforcing member: 353'; First body: 354; First pad: 355; Through-hole: 3551; Extension: 3552; First via: 3553; Conductor: 35 6; Bonding area: 357; Rigid board section: 36d, 36e, 36f, 36g, 36h, 36i, 36j, 36k, 361; Flexible board section: 37d, 37e, 37f, 37g, 37h, 37i, 37j, 37k, 371; Electromagnetic shielding layer: 41; Dielectric layer: 42; Base film layer: 43; Adhesive layer: 44; Circuit layer: 45; Ground wire: 451; Signal lines: 452-1, 452-2; Covering layer: 46; Cavity: 47; Battery: 50'; First battery: 51; Second battery: 52; Third battery: 53; Fourth battery: 54; First connecting plate: 5 51, 551'; Second connecting board: 552; Third connecting board: 553, 553'; Fourth connecting board: 554; Fifth connecting board: 555; Sixth connecting board: 556; Charger: 561'; Protection board: 562'; Charging chip: 61, 61'; System-on-a-chip: 62, 62'; PAMiD: 621; RF switch: 622; General purpose flash memory: 63, 63'; Electronic components: 64; Shielding frame: 65; Screen: 71; Mid-frame: 72; Recess: 721; Exterior cover: 73; Support plate: 74; Fixing block: 75; Reinforcing plate: 76; Speaker: 77; Type Port C: 78; Shaft cover: 79; First traction piece: 81; Second traction piece: 82; Adhesive layer: 83; Laser: 85; Prism: 851; Indenter: 86; Laser device: 861; Conductive paste: 87; Carrier plate: 88; Base: 881; Support member: 882; Forces: F1, F2; First direction: L1; Second direction: L2; Third direction: L3. Detailed Implementation

[0076] Please refer to Figure 1, which is a schematic diagram of the internal component distribution of the terminal device 100' provided by the related technology. Taking a two-fold mobile phone as an example, the terminal device 100' is divided into a first folding area 11', a first hinge area 21', and a second folding area 12', with the first hinge area 21' connecting the first folding area 11' and the second folding area 12'.

[0077] The terminal device 100' includes a first circuit board 31', a second circuit board 32', a flexible circuit board 35', a battery 50', a charging chip 61' (charge IC), and a system-on-a-chip (SOC) 62'. The first circuit board 31' is located in the first folding area 11', the second circuit board 32' is located in the second folding area 12', and the flexible circuit board 35' passes through the first pivot area 21' and is electrically connected to the first circuit board 31' and the second circuit board 32'. The battery 50' is electrically connected to the first circuit board 31', and both the charging chip 61' and the system-on-a-chip 62' are disposed on the first circuit board 31'.

[0078] Please refer to Figures 2, 3 and 4 together. Figure 2 is a schematic diagram of the connection principle between the mobile phone charger 561' and the mobile phone provided by the related technology. Figure 3 is a schematic diagram of the connection principle between the mobile phone charger 561', the radio frequency chip and the battery 50' provided by the related technology. Figure 4 is a schematic diagram of the heat generation of the mobile phone during the charging process provided by the related technology.

[0079] During charging, AC power sequentially passes through the charger 561', the first circuit board 31', the charging chip 61' and system-on-a-chip 62' connected to the circuit board, the protection board 562', and the battery 50'. Specifically, when AC power passes through the charging chip 61' and system-on-a-chip 62', the operation of these chips generates heat; when AC power passes through the protection board 562', the electronic components (including MOS) within the protection board generate heat; and when AC power passes through the battery 50', it generates heat as it passes through the tabs, electrodes, and battery materials. In other words, the terminal device 100' generates a certain amount of heat during charging. Due to the thin and light design of the terminal device 100', the installation space within the terminal device 100' is limited, and the charging chip 61' and system-on-a-chip 62' are very close to the outer surface of the terminal device 100'. If the heat is concentrated during charging, and the user holds the terminal device 100', it will affect the user experience.

[0080] Please refer to Figure 5, which is a schematic diagram of the electrical connection structure of a board-to-board (BTB) connector provided by related technologies.

[0081] Electrical connections between the first circuit board 31' and the flexible circuit board 35', and between the second circuit board 32' and the flexible circuit board 35', are typically achieved using a BTB (Block Connector). The specific structure of the BTB is as follows: Taking the electrical connection between the first circuit board 31' and the flexible circuit board 35' as an example, a female solder pad 311' is soldered onto the first circuit board 31', and the female solder pad 311' is positioned along the thickness direction of the first circuit board 31' on its surface; a male solder pad 351' is soldered onto the flexible circuit board 35', and the male solder pad 351' is positioned along the thickness direction of the flexible circuit board 35' on its surface. The male solder pad 351' is inserted into the female solder pad 311', thus achieving the electrical connection between the first circuit board 31' and the flexible circuit board 35'. In addition, the surface of the flexible circuit board 35' facing away from the male connector pad 351' is usually provided with an adhesive layer 352' and a reinforcing member 353' in sequence. The adhesive layer 352' bonds the reinforcing member 353' and the flexible circuit board 35' to increase the strength of the flexible circuit board 35' and facilitate the insertion of the male connector pad 351' provided on the flexible circuit board 35' into the female connector pad 311'.

[0082] After the first circuit board 31' and the flexible circuit board 35' are electrically connected, it is equivalent to increasing the overall thickness of the connected first circuit board 31' and flexible circuit board 35'. The increased thickness includes the thickness of the male connector pad 351' and female connector pad 311' after connection, as well as the mating clearance between the male connector pad 351' and female connector pad 311', which is detrimental to the thin and light structural design of the terminal device 100'. In addition, electrical connection via BTB is equivalent to increasing the number of transitions between the first circuit board 31' and the flexible circuit board 35', which is detrimental to signal strength. Transmission; typically, to ensure the stability of the male connector pad 351' and female connector pad 311' insertion, the areas of the male connector pad 351' and female connector pad 311' are set to be relatively large, reducing the wiring area of ​​the first circuit board 31' and the flexible circuit board 35'. The male connector pad 351' is fixed on the flexible circuit board 35'. If the flexible circuit board 35' needs to be replaced or repaired, the corresponding structure in the terminal device 100' needs to be removed, increasing costs. Moreover, there is a risk of damaging other components during the removal or reassembly process. Therefore, it is necessary to improve the above technology.

[0083] Please refer to Figures 6 and 7. Figure 6 is a structural schematic diagram of a terminal device 100 provided in an embodiment of this application, and Figure 7 is a structural schematic diagram of the terminal device 100 shown in Figure 6 from another direction.

[0084] In the embodiments shown in Figures 6 and 7, the terminal device 100 is a foldable screen phone. Foldable screen phones are popular with users because they offer a good viewing experience, a wide field of view, support split-screen functionality, and dual-screen operation, providing a relatively good user experience in both gaming and daily use. In other embodiments, the terminal device 100 can also be a foldable electronic product such as a laptop computer or a smartwatch. The terminal device 100 is divided into at least two folding areas and a hinge area located between two adjacent folding areas, the number of hinge areas being related to the number of folding areas.

[0085] The terminal device 100 is divided into at least two folding areas and a hinge area located between two adjacent folding areas. The folding areas can switch between a folded state and an unfolded state through the action of the hinge area. The terminal device 100 includes multiple circuit boards and electronic components disposed on the circuit boards. The electronic components include, but are not limited to, a processor, an antenna module, a Bluetooth module, a WiFi module, a GPS module, a power supply, a charging module, a screen display, and an operation module.

[0086] Please refer to Figures 8, 9, 10 and 11. Figure 8 is a schematic diagram of the internal component distribution of the terminal device 100 provided in the embodiment of this application. Figure 9 is a schematic diagram of the internal component distribution of the terminal device 100 provided in the embodiment of this application from another position. Figure 10 is a cross-sectional schematic diagram of the terminal device 100 provided in the embodiment of this application in an unfolded state. Figure 11 is a cross-sectional schematic diagram of the terminal device 100 provided in the embodiment of this application in a folded state.

[0087] In this embodiment, the terminal device 100 is divided into two folding areas and one hinge area, named the first folding area 11, the second folding area 12, and the first hinge area 21, respectively. The first hinge area 21 connects the first folding area 11 and the second folding area 12. The first folding area 11 and the second folding area 12 can switch between a folded state and an unfolded state through the function of the first hinge area 21. Specifically, the first folding area 11 and the second folding area 12 can be unfolded through the first hinge area 21, which is the unfolded state of the terminal device 100; the first folding area 11 and the second folding area 12 can be stacked on top of each other through the first hinge area 21, which is the folded state of the terminal device 100.

[0088] For ease of explanation, we define a first direction L1, a second direction L2, and a third direction L3 that are perpendicular to each other. The first direction L1 is the direction in which the first folding area 11, the second folding area 12, and the first pivot area 21 are arranged sequentially when the terminal device 100 is in the unfolded state. The second direction L2 is the direction of the rotation axis of the first folding area 11 and the second folding area 12. The third direction L3 is the direction in which the first folding area 11 and the second folding area 12 are stacked when the terminal device 100 is in the folded state. In this embodiment, the first direction L1, the second direction L2, and the third direction L3 are perpendicular to each other. It is understood that in an actual terminal device 100, the first direction L1, the second direction L2, and the third direction L3 are not limited to being perpendicular to each other; they can be adjusted according to the specific terminal device 100. Even if designed to be perpendicular, a certain tolerance (e.g., ±1%) is allowed.

[0089] Please refer again to Figure 9. The terminal device 100 includes a first circuit board 31, a second circuit board 32, and a flexible circuit board 35. The first circuit board 31 is located in the first folding area 11, the second circuit board 32 is located in the second folding area 12, and the flexible circuit board 35 passes through the first pivot area 21 and is electrically connected to the first circuit board 31 and the second circuit board 32. Specifically, the flexible circuit board 35 is electrically connected to the first circuit board 31 via laser welding, and / or the flexible circuit board 35 is electrically connected to the second circuit board 32 via laser welding. In this embodiment, the flexible circuit board 35 is electrically connected to the first circuit board 31 via laser welding, and the flexible circuit board 35 is electrically connected to the second circuit board 32 via laser welding.

[0090] The terminal device 100 includes a screen 71, two mid-frames 72, and an outer cover 73. The screen 71 is a foldable screen, located in the first folding area 11, the hinge area, and the second folding area 12. The two mid-frames 72 are located in the first folding area 11 and the second folding area 12, respectively. The outer cover 73 is located in the first hinge area 21. Taking the terminal device 100 in its unfolded state as an example, the areas where the first circuit board 31 and the flexible circuit board 35 are electrically connected are stacked along the third direction L3 and are parallel to the screen 71. The area where the flexible circuit board 35 is electrically connected to the first circuit board 31 is located on the side of the first circuit board 31 opposite to the screen 71.

[0091] Please refer to Figures 12, 13 and 14. Figure 12 is a structural schematic diagram of the first circuit board 31 and the flexible circuit board 35 after being connected according to an embodiment of this application. Figure 13 is a cross-sectional schematic diagram of the first circuit board 31 and the flexible circuit board 35 connected by a conductor 356 according to an embodiment of this application. Figure 14 is a structural schematic diagram of the laser-welded first circuit board 31 and the flexible circuit board 35 according to an embodiment of this application.

[0092] The flexible circuit board 35 includes a first body 354 and a first pad 355. The first pad 355 includes a through portion 3551 and an extension portion 3552. The through portion 3551 passes through the first body 354 and surrounds it to form a first through hole 3553. The extension portion 3552 is located at both ends of the through portion 3551 and is located on the surface of the first body 354.

[0093] The first circuit board 31 includes a second body 312 and a second pad 313 stacked along a third direction L3, with the second pad 313 located on the surface of the second body 312. The terminal device 100 includes a conductor 356, which fills a first through-hole 3553 and connects to a through portion 3551. It also overflows onto two opposing surfaces of the flexible circuit board 35 and connects to an extension portion 3552. The conductor 356 located on the side of the first circuit board 31 is also connected to the second pad 313. The conductor 356 is approximately I-shaped and is formed by laser welding of conductive paste 87. The surface of the conductor 356 connected to the first circuit board 31 and the surface exposed on the flexible circuit board 35 are both parallel to the screen 71. The conductive paste 87 can be made of solder paste, which has a melting point of 130℃-150℃ or similar low temperature. The solder paste may contain components such as SnBiAg, SnInAg, and SiZnAg. Alternatively, a solder paste with a relatively high melting point, such as high-temperature solder paste with the model number SAC305, can be used. The cross-section of the first through-hole 3553 along the direction perpendicular to the third direction L3 can be circular, square, or elliptical. The extension 3552 can also be circular, square, or elliptical. The portion of the conductor 356 located on the surface of the extension 3552 can also be circular, square, or elliptical.

[0094] Please refer to Figure 14. Taking the assembly of the first circuit board 31 with the mid-frame 72 and flexible circuit board 35 of the mobile phone as an example, during the assembly process, a base 881 and a support 882 are set on the carrier board 88. The mid-frame 72 is inserted into the base 881 along the third direction L3 to limit the position of the mid-frame 72. The first circuit board 31 is placed along the first direction L1. Electronic components 64 and a frame 65 can be connected to the first circuit board 31. The frame 65 can be a shielding frame. The support 882 is used to support the frame 65, thereby supporting the first circuit board 31. The first circuit board 31 is provided with positioning devices (not shown in the figure). The number of positioning devices can be 2-4. The positioning devices are used to position the first circuit board 31 and the mid-frame 72 during the fixing process. After the first circuit board 31 and the mid-frame 72 are positioned, they are fixed with screws. The positioning devices are designed with rounded corners. A spring contact (not shown in the figure) can also be connected to the first circuit board 31. The spring contact is connected to the first circuit board 31 by soldering with solder paste.

[0095] Conductive paste 87 is placed on the surface of the second pad 313 of the first circuit board 31; the flexible circuit board 35 is passed between the middle frame 72 and the shaft cover 79, the shaft cover 79 being the housing part of the rotating shaft; the first pad 355 of the flexible circuit board 35 is aligned with the conductive paste 87, the conductive paste 87 is exposed in the first through hole 3553, and the part of the flexible circuit board 35 that needs to be soldered to the first circuit board 31 is parallel to the first circuit board 31; a transparent glass pressure head 86 and a laser device 861 are provided on the surface of the flexible circuit board 35 facing away from the first circuit board 31. A laser emitting device emits a laser 85. The laser 85 is reflected by a prism 851 and dispersed by a laser device 861, passing through a glass pressure head 86 and irradiating conductive paste 87 to melt it. Under the pressure of the glass pressure head 86, the conductive paste 87 rises along the surface of the first through-hole 3553 in a direction away from the first circuit board 31 and overflows. After solidification, the conductive paste 87 forms a conductor 356, which connects the first pad 355 and the second pad 313, thereby achieving an electrical connection between the first circuit board 31 and the flexible circuit board 35. In this embodiment, the second circuit board 32 and the flexible circuit board 35 are also laser-welded using the same structure and method. The specific laser welding steps are not described here.

[0096] In some embodiments, to increase the connection reliability between the first circuit board 31 and the flexible circuit board 35, and between the second circuit board 32 and the flexible circuit board 35, adhesive dispensing can also be applied between the first circuit board 31 and the flexible circuit board 35, and between the second circuit board 32 and the flexible circuit board 35.

[0097] Please refer to Figure 15, which is a schematic diagram of the connection between the first circuit board 31 and the flexible circuit board 35 provided in some other embodiments of this application.

[0098] A first through-hole 3553 is formed on the flexible circuit board 35. The flexible circuit board 35 includes a first body 354 and a first pad 355. The first pad 355 penetrates the first body 354 and surrounds the first through-hole 3553. A second through-hole 314 is formed on the first circuit board 31. The first circuit board 31 includes a second body 312 and a second pad 313. The second pad 313 penetrates the second body 312 and surrounds the second through-hole 314. Before laser welding, conductive paste 87 is placed between the first circuit board 31 and the flexible circuit board 35, with the first through-hole 3553 and the second through-hole 314 corresponding. A conductor 356 connecting the first circuit board 31 and the flexible circuit board 35 is formed by laser welding. The conductor 356 is housed in the first through-hole 3553 and the second through-hole 314, and is also located between the first body 354 and the second body 312. The conductor 356 has a roughly "+" shaped structure. The second circuit board 32 and the flexible circuit board 35 are welded using the same structure and method described above. The specific laser welding steps will not be repeated here. In other embodiments, without affecting other components of the terminal device 100, reflow soldering can also be used to achieve the electrical connection between the first circuit board 31 and the flexible circuit board 35.

[0099] Referring again to Figure 9, the terminal device 100 may further include a first battery 51, a second battery 52, a charging chip 61, and a system-on-a-chip 62. The first battery 51 is located in the first folding area 11, and the second battery 52 is located in the second folding area 12. The first battery 51 is electrically connected to the first circuit board 31, and the second battery 52 is electrically connected to the second circuit board 32. The first battery 51 is electrically connected to the first circuit board 31 through a first connecting plate 551, and the second battery 52 is electrically connected to the second circuit board 32 through a second connecting plate 552. The terminal device 100 also includes a Type-C port 78, which is used for connecting an external charger. The Type-C port 78 is electrically connected to the first circuit board 31 through a third connecting plate 553. In this embodiment, the first circuit board 31 is the main board, and the second circuit board 32 is the secondary board. The charging chip 61 and the system-on-a-chip 62 are both disposed on the first circuit board 31. The charging chip 61 is used to monitor and control the current and voltage of the first battery 51 and the second battery 52 in real time during the charging process to ensure safety during the charging process.

[0100] The first connecting board 551, the second connecting board 552, and the third connecting board 553 can all be circuit boards. The electrical connection between the first connecting board 551 and the first circuit board 31, the electrical connection between the second connecting board 552 and the second circuit board 32, and the electrical connection between the third connecting board 553 and the first circuit board 31 include, but are not limited to, board-to-board (BTB) connectors, film-on-board (FOB) connections, etc. In this embodiment, the first connecting board 551 and the first circuit board 31, the second connecting board 552 and the second circuit board 32, and the third connecting board 553 and the first circuit board 31 are all connected by BTB.

[0101] In this embodiment, when charging the first battery 51, the current flow path includes: charger, Type-C port 78, first connecting board 551, first circuit board 31, charging chip 61, protection board of the first battery 51, tabs of the first battery 51, and battery cell of the first battery 51; when charging the second battery 52, the current flow path includes: charger, Type-C port 78, first connecting board 551, first circuit board 31, charging chip 61, laser welding point of first circuit board 31 and flexible circuit board 35, flexible circuit board 35, laser welding point of flexible circuit board 35 and second circuit board 32, protection board of the second battery 52, tabs of the second battery 52, and battery cell of the second battery 52.

[0102] In this embodiment, replacing at least one BTB electrical connection with laser welding helps reduce the thickness of the electrical connection area (i.e., the thickness of the terminal device 100 along the third direction L3). This is equivalent to increasing the distance between the electrical connection area and the outer surface (i.e., the casing) of the terminal device 100. In other words, during charging, this increases the distance between the user and the heat source, thus reducing the temperature felt by the user. Furthermore, using laser welding for direct electrical connection reduces the number of connection steps, the current flow path, and the resistance, thereby reducing the heat generated during charging and further reducing the temperature felt by the user. Specifically, in this embodiment, compared to related technologies using BTB for electrical connection, the temperature reduction achieved by this application embodiment is approximately 0.3℃-3℃.

[0103] Furthermore, the flexible circuit board 35 and the first circuit board 31 are electrically connected using FOB laser welding. The connection interface includes the circuit layer of the flexible circuit board 35 and the first pad 355, the conductor 356 and the first pad 355 and the second pad 313 respectively, and the circuit layer and the second pad 313 in the first circuit board 31, i.e., a total of three connection interfaces. If the BTB connection method is used, the connection interface includes the surface of the circuit layer in the first circuit board 31, the solder joint between the first circuit board 31 and the female connector pad 311', the mating gap between the female connector pad 311' and the male connector pad 351', the male connector pad 351', the solder joint between the male connector pad 351' and the flexible circuit board 35, and the surface of the circuit layer in the flexible circuit board 35, i.e., a total of seven connection interfaces. The connection interfaces required for BTB connection and FOB connection are summarized in the table below. Therefore, in comparison, the laser welding of the flexible circuit board 35 and the first circuit board 31 can also achieve simplified radio frequency signal transmission in the welding area.

[0104] Please refer to Figure 16, which is a comparative schematic diagram of the structure of connecting the first circuit board 31 and the flexible circuit board 35 using BTB and laser welding, respectively. In Figure 16(a), the first circuit board 31 and the flexible circuit board 35 are connected by BTB, and in Figure 16(b), the first circuit board 31 and the flexible circuit board 35 are connected by laser welding. The dashed areas in Figure 16 and other illustrations represent the areas connected by BTB.

[0105] When laser welding is used, the area occupied by the flexible circuit board 35 can be smaller than the area occupied by the BTB, and the distance A between the edge of the projection of the system-on-a-chip 62 along the third direction L3 onto the first circuit board 31 and the flexible circuit board 35 can be greater than the distance A' in (a). In some embodiments, the distance A between the edge of the projection of the system-on-a-chip 62 along the third direction L3 onto the first circuit board 31 and the flexible circuit board 35 can be 0.5mm-30mm. In addition, laser welding, compared to BTB electrical connection, is beneficial for reducing the thickness of the terminal device 100 along the third direction L3.

[0106] As shown in Figure 16, the first circuit board 31' is also connected to a universal flash storage 63' (UFS), a second connection board 551', and a third connection board 553'. Taking the universal flash storage 63, second connection board 551, and third connection board 553 located on the first circuit board 31 as an example, the universal flash storage 63 and the system-on-a-chip 62 are spaced apart. The universal flash storage 63 is the main medium for storing the operating system and applications in the mobile phone, providing a large storage space for the phone, allowing users to install and run various applications. The second connection board 551 is used to connect to the first battery 51; the third connection board 553 is used to connect to the Type-C port 78.

[0107] Please refer to Figures 17, 18A and 18B. Figure 17 is a top view of the terminal device 100 provided in an embodiment of this application. Figure 18A is a cross-sectional view of a portion of the terminal device 100 in some other embodiments. Figure 18B is a cross-sectional view of a portion of the terminal device 100 shown in Figure 17 along the II direction.

[0108] Please refer to Figure 18A. The terminal device 100 also includes a support plate 74, a fixing block 75, a reinforcing plate 76, and an outer cover 73. There are two support plates 74, located in the first folding area 11 and the second folding area 12, respectively. The support plates 74 are used to support the screen 71 in the corresponding area. The fixing block 75 is located in the pivot area. The flexible circuit board 35 passes through the first pivot area 21 between the fixing block 75 and the outer cover 73. The reinforcing plate 76 is disposed between the outer cover 73 and the flexible circuit board 35 to reinforce the strength of the flexible circuit board 35.

[0109] In this embodiment, the BTB electrical connection method is adopted. When it is necessary to assemble the screen 71, support plate 74, fixing block 75, middle frame 72, outer cover 73 and flexible circuit board 35 in the terminal device 100, since the flexible circuit board 35 is provided with male solder pads 351' of a certain thickness, it is usually necessary to assemble them in the order of screen 71, support plate 74, fixing block 75, flexible circuit board 35, reinforcing plate 76, outer cover 73 and middle frame 72, or in the reverse order of middle frame 72, outer cover 73, reinforcing plate 76, flexible circuit board 35, fixing block 75, support plate 74 and screen 71.

[0110] If the flexible circuit board 35 fails and needs to be disassembled or replaced, since components such as the screen 71, support plate 74, fixing block 75, and outer cover 73 are already installed, and the components in the terminal device 100 are densely arranged, the gap reserved for the flexible circuit board 35 is small, usually not exceeding 0.5mm. The thickness of the male solder pad 351' of the flexible circuit board 35 is difficult to pass through the narrow gap. Therefore, when it is necessary to disassemble or replace the flexible circuit board 35, it is necessary to disassemble it in the reverse order of the above installation to obtain the flexible circuit board 35. After repair or replacement, the disassembled components must be reassembled. The above steps are prone to damage to components, such as damage to the screen 71. In addition, the actual terminal device 100 also contains other components, such as hinges, making the assembly and disassembly steps more difficult.

[0111] Please refer to Figure 18B. The difference between Figure 18B and Figure 18A is that the first circuit board 31 and the flexible circuit board 35 in Figure 18B are electrically connected by laser welding. The surface of the flexible circuit board 35 does not have a thick male solder pad 351'. The overall thickness of the flexible circuit board 35 is thinner, which allows the flexible circuit board 35 to be disassembled and assembled without disassembling other components in the terminal device 100.

[0112] Please refer to Figure 18C, which is a cross-sectional schematic diagram of a portion of a terminal device 100 provided in other embodiments of this application. In this embodiment, the dashed circles in the figure represent flexible circuit boards 35 that can be bent around a virtual inner diameter.

[0113] Please refer to Figures 19 and 20. Figure 19 is a cross-sectional flowchart of bonding the first traction piece 81 to the flexible circuit board 35 according to an embodiment of this application. Figure 20 is a top view flowchart of bonding the first traction piece 81 and the second traction piece 82 to the flexible circuit board 35 according to an embodiment of this application.

[0114] Specifically, adhesive areas 357 are provided at both ends of the flexible circuit board 35 along the first direction L1. When it is necessary to remove the flexible circuit board 35, the conductor 356 can be melted by laser irradiation to separate the flexible circuit board 35 from the first circuit board 31, the flexible circuit board 35 from the second circuit board 32. Adhesive layers 83 are coated at the ends of the first traction piece 81 and the second traction piece 82. The first traction piece 81 is bonded to the adhesive area 357 of the flexible circuit board 35 located in the first folding area 11, and the second traction piece 82 is bonded to the adhesive area 357 of the flexible circuit board 35 located in the second folding area 12. In this embodiment, the first traction piece 81 and the second traction piece 82 are both Mylar sheets.

[0115] In some embodiments, the thickness B of the first traction piece 81 along the third direction L3 is 0.01mm-3mm, the thickness C of the adhesive layer 83 along the third direction L3 is 0.01mm-2mm, the width D of the adhesive layer 83 coated on the first traction piece 81 and the second traction piece 82 along the first direction L1 is 0.02mm-50mm, the width E of the adhesive area 357 along the first direction L1 is D×90% and satisfies 0.02mm≤E≤48mm, the distance F between the adhesive area 357 and the first pad 355 is 0.02mm-10mm, and the distance H from the end of the adhesive layer 83 away from the flexible circuit board 35 to the flexible circuit board 35 is 0.02mm-10mm. The meaning of each letter and a summary of the dimensions are shown in the table below.

[0116] In some embodiments, the bonding area 357 may be subjected to plasma etching to increase its roughness, thereby increasing the adhesion between the flexible circuit board 35 and the adhesive layer 83. The roughness Rz of the bonding area 357 is ≥1μm. In some specific embodiments, the roughness Rz can be 2.5μm, 4.8μm, 5.6μm, or 7.8μm, etc.

[0117] Please refer to Figures 21 and 22. Figure 21 is a cross-sectional flowchart of the process of disassembling the flexible circuit board 35 from the terminal device 100 using the first traction piece 81 and the second traction piece 82 in an embodiment of this application. Figure 22 is a cross-sectional flowchart of the process of assembling the flexible circuit board 35 into the terminal device 100 using the first traction piece 81 and the second traction piece 82 in an embodiment of this application.

[0118] Please refer to Figure 21. A force F1 can be applied to the second traction piece 82 to pull the second traction piece 82 out of the second folding area 12, causing the flexible circuit board 35 to exit sequentially from the first folding area 11 and the first pivot area 21. Thus, the first traction piece 81, which is attached to the flexible circuit board 35, passes through the first pivot area 21. The two ends of the first traction piece 81 are located in the first folding area 11 and the second folding area 12, respectively. That is, the first traction piece 81 is temporarily located in the terminal device 100.

[0119] Referring to Figure 22, when repairing or replacing and requiring reinstallation of the flexible circuit board 35, the first traction piece 81 is reattached to the adhesive area 357 of the flexible circuit board 35. The first traction piece 81 is then pulled out from the first folding area 11, sequentially exiting through the second folding area 12, the first pivot area 21, and back to the first folding area 11. Simultaneously, the flexible circuit board 35 is pulled through the first pivot area 21, with both ends of the flexible circuit board 35 located in the first folding area 11 and the second folding area 12, respectively. The two ends of the flexible circuit board 35 are then electrically connected to the first circuit board 31 and the second circuit board 32, respectively. Using the first traction piece 81 and the second traction piece 82 to assist in the disassembly and installation of the flexible circuit board 35 reduces the number of components removed and the risk of component damage compared to related technologies.

[0120] It is understandable that in the initial assembly of the terminal device 100, other components can be assembled and the first traction piece 81 can be pre-embedded. When it is necessary to install the flexible circuit board 35, the first traction piece 81 can be bonded to the flexible circuit board 35 before installation.

[0121] Please refer to Figures 23 and 24. Figure 23 is a cross-sectional schematic diagram of the flexible circuit board 35 provided in some embodiments of this application, and Figure 24 is a cross-sectional schematic diagram of the flexible circuit board 35 provided in other embodiments of this application.

[0122] The flexible circuit board 35 has multiple circuit layers 45, such as two, three or four layers. The flexible circuit board 35 also includes an electromagnetic shielding layer 41, which is located on the surface of the cover layer 46 of the flexible circuit board 35. The electromagnetic shielding layer 41 is the outermost layer of the flexible circuit board 35. The bonding area 357 and the area where the second pad 313 of the flexible circuit board 35 are located are not provided with electromagnetic shielding layer 41.

[0123] In the embodiment shown in Figure 24, electromagnetic shielding layers 41 are provided on both opposite surfaces of the flexible circuit board 35, and the flexible circuit board 35 includes three circuit layers 45. The flexible circuit board 35, from top to bottom and with corresponding thicknesses, consists of an electromagnetic shielding layer 41 (10.0 μm), a dielectric layer 42 (12.3 μm), an adhesive layer 44 (17.0 μm), a circuit layer 45 (22.0 μm), a dielectric layer 42 (12.5 μm), a base film layer 43 (25.0 μm), a dielectric layer 42 (12.5 μm), an adhesive layer 44 (17.0 μm), a circuit layer 45 (22.0 μm), a dielectric layer 42 (12.5 μm), a base film layer 43 (25.0 μm), a dielectric layer 42 (12.5 μm), a circuit layer 45 (22.0 μm), an adhesive layer 44 (17.0 μm), a dielectric layer 42 (12.3 μm), and an electromagnetic shielding layer 41 (10.0 μm). Each circuit layer 45 is formed by a copper foil (7.0 μm) and a copper plating layer (15.0 μm) formed on the copper foil. In some manufacturing steps, the copper foil is subjected to a copper reduction process, and the thickness of the copper foil is reduced accordingly, for example, to 6.0 μm-8.0 μm. The dielectric layer 42 and the base film layer 43 are both made of polyimide (PI). In other embodiments, the overall thickness of the flexible circuit board 35 and the thickness of each layer can be adjusted according to actual needs, and the adjustment range is 20%-300% of the above-mentioned overall thickness or the thickness of each layer. The dimensions of each layer are summarized in the table below.

[0124] Please refer to Figures 25A and 25B, which are both top views of the flexible circuit board 35 provided in some embodiments of this application. In the embodiments shown in Figures 25A and 25B, the flexible circuit board 35 has multiple rows of cavities 47 along the first direction L1, facilitating bending of the flexible circuit board 35 in the areas where the cavities 47 are provided. The flexible circuit board 35 has three rows of cavities 47, with the two rows of cavities 47 on both sides corresponding to the ends of the outer cover 73, and the middle row of cavities 47 corresponding to the middle area of ​​the outer cover 73. The number of cavities 47 in each row can be one or more, and each cavity 47 can be formed by removing the electromagnetic shielding layer 41 or adhesive layer 44 of the corresponding area. In Figure 25A, the area of ​​the flexible circuit board 35 used for welding is provided with a first solder pad 355, which can be used for laser welding, and in Figure 25B, the area of ​​the flexible circuit board 35 used for welding can be connected using BTB.

[0125] Please refer to Figure 26, which is a cross-sectional schematic diagram of a flexible circuit board 35 provided in some embodiments of this application. When the number of circuit layers 45 in the flexible circuit board 35 is two, a ground layer is provided on one side of the flexible circuit board 35 to provide a reference potential in the circuit design and help reduce electromagnetic interference; the other side is covered with an electromagnetic shielding layer 41 to reduce electromagnetic radiation or interference and improve the stability and reliability of signal transmission. In other embodiments, when the number of circuit layers 45 in the flexible circuit board 35 is three or more, ground layers are provided on both opposite sides of the flexible circuit board 35, and electromagnetic shielding layers 41 may also be provided.

[0126] In this embodiment, the circuit layer 45 in the flexible circuit board 35 has two layers. To reduce signal interference and noise, the signal line 452-1 is surrounded by a ground line 451 (GND), which can ensure that the signal is more stable during transmission. Each circuit layer 45 includes a signal line and a ground line 451. The two signal lines are signal line 452-1 and signal line 452-2, respectively. The wiring width J of signal line 452-1 or signal line 452-2 is 0.02mm-2mm. The spacing K between the two signal lines and the ground line 451 is 0.5J-2J. The wiring width L of the ground line 451 is 1J-5J. The orthographic projection of one signal line 452-1 onto the ground line 451 of the other layer is located within the area of ​​the ground line 451, and the distance between the projection edge of the signal layer 452-1 and the edge of the ground line 451 is greater than or equal to 0.01mm. The specific details are summarized in the table below.

[0127] Please refer to Figure 27A, which is a structural schematic diagram of the first pad 355 of the flexible circuit board 35 provided in an embodiment of this application. The first through hole 3553 on the flexible circuit board 35 can be elliptical, and the first pad 355 of the flexible circuit board 35 is rectangular in a top view from one direction. The diameter a of the first through hole 3553 along the short side direction is 0.045mm-0.45mm, the width b of the first pad 355 along the short side direction is 0.105mm-1.05mm, the diameter c of the first through hole 3553 along the long side direction is 0.045mm-0.45mm, and the width d of the first pad 355 along the long side direction is 0.105mm-1.05mm. The number of first pads 355 is at least two rows, at least one row is used for grounding, and at least one row is used for conducting signals. The distance e between the first pad 355 used for grounding and the first pad 355 used for conducting signals is 0.075mm-0.75mm. The width g of the signal line connected to the first pad 355 is 0.0315mm-0.35mm. The impedance of the control signal line is within 50Ω. The distance m between two adjacent first pads 355 used for conducting signals is 0.075mm-0.75mm. The spacing n between two adjacent first pads 355 is 0.18mm-1.8mm. Two adjacent first pads 355 include two first pads 355 in the left-right or up-down direction as shown in the figure. A summary of the above dimensions is shown in the table below.

[0128] Please refer to Figure 27B, which is a schematic diagram of the structure of the first pad 355 of the flexible circuit board 35 provided in some other embodiments of this application. The first pad 355 located on the outer side of the flexible circuit board 35 can be designed in a dumbbell shape. The dumbbell-shaped first pad 355 has larger dimensions at both ends and a smaller dimension in the middle, which is beneficial for improving welding strength.

[0129] The first circuit board 31, the flexible circuit board 35 and / or the second circuit board 32 are designed with power signals, charging VBUS (Voltage Bus), general purpose input / output (GPIO) ports, sensors, audio signals, antennas, baseband power, control signals, etc., and other signals are ground signals.

[0130] Radio frequency (RF) signals are typically highly sensitive to interference. Designing a complete and independent ground plane 451 around RF signals ensures their stability and purity. Similar to RF signals, screen signals and sensors also require a stable transmission environment, and ground plane 451 designs are also incorporated around them. The distance between the antenna pads and the power signal pads is at least 3mm to ensure the antenna signal is not interfered with by the power signal. The position of the user's handheld terminal device 100 can also affect the antenna signal. The distance between the antenna ground plane 451 and the ground plane 451 of other signals is at least 2mm, and the distance between the antenna ground plane 451 trace and the trace of other signal ground plane 451 is at least 3mm to prevent interference between ground planes 451. When the antenna ground plane 451 is close to other signal lines, its width should be at least 0.1mm to ensure signal stability.

[0131] The following lists the different types of signals and connections, and the objects to which they are ultimately connected. Among them, the power signal provides electrical energy, typically obtained from the first battery 51 and the second battery 52, and distributed to various components on the first circuit board 31 and the second circuit board 32. The baseband power supply provides power to the baseband chip dedicated to the terminal device 100. The baseband chip is a key component in communication devices such as mobile phones used to process communication signals (such as voice and data). The radio frequency (RF) signal is the signal used in wireless communication, such as mobile phone communication and WiFi. The RF antenna switch controls which antenna transmits or receives the RF signal. The audio signal is the electronic representation of sound information, and is sent to the speaker 77 (BOX) for processing or playback. The charging VBUS refers to the charging bus or charging power line. The charging chip 61 is responsible for controlling and managing the charging process to ensure that the battery is charged safely and effectively. GPIO is the interface of the terminal device 100, used for system interaction with other hardware. GPIO is connected to the chip on the second circuit board 32 and can be used for data transmission, control, or other interactive functions. Test pins are used for testing or debugging. BTB testing refers to board-to-board testing, used to verify the reliability of connections between two or more circuit boards. Sensors are components used to detect and measure physical quantities (such as temperature, pressure, acceleration, etc.). Semiconductor sensors include accelerometers, gyroscopes, and barometers, used to measure acceleration, angular velocity, and atmospheric pressure, respectively. Screen signals are signals used to communicate with screen 71 and can include image data, control signals, etc. These signals ensure that screen 71 can display content correctly and communicate effectively with the first circuit board 31. A summary of the above-mentioned different types of signals and connections, and the objects to which they are ultimately connected, is shown in the table below.

[0132] Please refer to Figure 28, which is a schematic diagram of the connection of line layer 45 provided in an embodiment of this application. In some embodiments, power signal, GPIO, charger interface, GND, screen signal, RF signal, another power signal, and the same line layer 45 are connected. This line layer 45 is mainly responsible for power supply, communication with external devices, and charging functions. Power supply is the foundation for device operation. GPIO allows the terminal device 100 to exchange data with other electronic components or devices. The charger interface is used to connect to an external power source for charging. Grounding connection is crucial for ensuring circuit safety and stability. Power signal, GND, and another power signal are connected to another line layer 45. Power signal, organic light-emitting diode, test interface, GPIO, RF signal, another power signal, and yet another line layer 45 are connected. The organic light-emitting diode serves as a display element. Each line layer 45 carries different electronic components 64 and connections, collectively constituting the electrical system of the terminal device 100, responsible for functions such as power supply, communication, charging, wireless communication, display, testing, and debugging.

[0133] Please refer to Figure 29, which is a schematic diagram of the internal component distribution of the terminal device 100a provided in some other embodiments of this application. The difference from the embodiment shown in Figure 8 is that in the embodiment shown in Figure 29, the terminal device 100a is divided into a first folding area 11, a first pivot area 21, a second folding area 12, a second pivot area 22, and a third folding area 13 connected in sequence. Multiple circuit boards include a first circuit board 31, a second circuit board 32, and a third circuit board 33; the first circuit board 31 is located in the first folding area 11, the second circuit board 32 is located in the second folding area 12, and the third circuit board 33 is located in the third folding area 13; a flexible circuit board 35a passes through the first pivot area 21, the second folding area 12, and the second pivot area 22 and is electrically connected to the first circuit board 31, the second circuit board 32, and the third circuit board 33; the flexible circuit board 35a is electrically connected to the first circuit board 31 after laser welding, and / or the flexible circuit board 35a is electrically connected to the second circuit board 32 after laser welding, and / or the flexible circuit board 35a is electrically connected to the third circuit board 33 after laser welding.

[0134] In this embodiment, the flexible circuit board 35a is approximately T-shaped, and the flexible circuit board 35a is electrically connected to the second circuit board 32 by laser welding. The flexible circuit board 35a can pass through multiple pivot areas, which is beneficial for improving the quality of radio frequency signals; and it is also beneficial for reducing the number of BTBs, thereby increasing the circuit layout area of ​​the flexible circuit board 35a.

[0135] Terminal device 100a includes a first battery 51, a second battery 52, and a third battery 53. The first battery 51 is located in the first folding area 11 and electrically connected to the first circuit board 31. The second battery 52 is located in the second folding area 12 and electrically connected to the second circuit board 32. The third battery 53 is located in the third folding area 13 and electrically connected to the third circuit board 33 via a fourth connecting plate 554. Terminal device 100a also includes a Type-C port 78 and a speaker 77. The Type-C port 78 is located in the first folding area 11 and electrically connected to the first circuit board 31. The speaker 77 is located in the third folding area 13 and electrically connected to the third circuit board 33. A recess 721 is formed in the middle frame 72 located in the second folding area 12. The flexible circuit board 35a located in the second folding area 12 can be embedded in the recess 721 to reduce the thickness of terminal device 100a.

[0136] During the charging process, when charging the first battery 51, the current flow path includes: charger, Type-C port 78, first connecting board 551, first circuit board 31, charging chip 61, protection board of the first battery 51, tabs of the first battery 51, and battery cell of the first battery 51; when charging the second battery 52, the current flow path includes: charger, Type-C port 78, first connecting board 551, first circuit board 31, charging chip 61, laser welding point of first circuit board 31 and flexible circuit board 35a, flexible circuit board 35a, laser welding point of flexible circuit board 35a and second circuit board 32, protection board of the second battery 52, tabs of the second battery 52, and battery cell of the second battery 52; when charging the third battery 53 ... protection board of the first battery 51, first connecting board 551, first circuit board 31, charging chip 61, protection board of the first battery 51, first connecting board 551, first circuit board 31, charging chip 61, laser welding point of first circuit board 31 and flexible circuit board 35a, laser welding point of flexible circuit board 35a and second circuit board 32, protection board of the second battery 52, tabs of the second battery 52, and battery cell of the second battery 52; when charging the third battery The system includes a C-port 78, a first connecting board 551, a charging chip 61, laser welding points of the first circuit board 31 and flexible circuit board 35a, flexible circuit board 35a, laser welding points of flexible circuit board 35a and third circuit board 33, third circuit board 33, a protection board for the third battery 53, tabs of the third battery 53, and the battery cell of the third battery 53. During the charging process of the third battery 53, the signal transmitted from the first circuit board 31 does not need to pass through the second circuit board 32 and can be directly transmitted to the third circuit board 33 through the flexible circuit board 35a.

[0137] In this embodiment, the flexible circuit board 35a is electrically connected to the first circuit board 31, which is connected to the charging chip 61, by laser welding. This helps to reduce the thickness of the weld and increases the distance between the user and the heat source during charging, thus reducing the temperature felt by the user. In addition, using laser welding for direct electrical connection helps to reduce the number of transfers, the current flow path, and the resistance, thereby reducing the heat generated during charging and further reducing the temperature felt by the user. One flexible circuit board 35a can simultaneously electrically connect the first circuit board 31, the second circuit board 32, and the third circuit board 33, thereby improving the quality of the radio frequency signal. Laser welding can reduce the number of BTBs and increase the circuit layout area. At the same time, the flexible circuit board 35a can be disassembled and installed using the above-mentioned method in conjunction with the first traction piece 81 and the second traction piece 82.

[0138] The first circuit board 31 is also connected to components such as PAMiD621 (Power Amplifier Module integrated with Duplexer) and RF switch 622 (SW). The main function of PAMiD621 is to amplify, filter and switch the signal when the terminal device 100a transmits the signal to ensure that the signal can be efficiently transmitted to the antenna and sent out. RF switch 622 is used to switch the signal path between multiple frequency bands to ensure that the terminal device 100a can receive and send signals from different networks.

[0139] Please refer to Figures 30A and 30B, which are schematic diagrams of the internal component distribution of the terminal device 100b provided in other embodiments of this application.

[0140] The difference from the embodiment shown in Figure 29 is that in the embodiment shown in Figure 30A, the flexible circuit board 35b is approximately T-shaped, and the flexible circuit board 35b and the second circuit board 32 can be electrically connected via a BTB (as shown in Figure 30A) or FOB (as shown in Figure 30B) connection method. In other embodiments, the electrical connection method between the flexible circuit board 35b and the second circuit board 32 is not limited to the above two methods; it can also be achieved by connecting other circuit boards for conversion, etc.

[0141] The flexible circuit board 35b passes through the second folding area 12. The step of installing the flexible circuit board 35b can be carried out after the second battery 52 is installed. The flexible circuit board 35b can be disposed on the surface of the second battery 52. ​​Compared with the embodiment in which a groove 721 for embedding the flexible circuit board 35b is provided in the middle frame 72 to reduce the overall thickness of the terminal device 100b, this embodiment does not provide a groove 721 on the middle frame 72, which is beneficial to improving the strength of the middle frame 72.

[0142] In this embodiment, the terminal device 100b includes two charging chips 61, which are respectively disposed on the first circuit board 31 and the second circuit board 32. The charging chip 61 disposed on the first circuit board 31 is used to monitor and control the current and voltage of the first battery 51 and the third battery 53 during the charging process, and the charging chip 61 disposed on the second circuit board 32 is used to monitor and control the current and voltage of the second battery 52 during the charging process.

[0143] During the charging process, the current flow path when charging the first battery 51 and the third battery 53 is the same as that in the embodiment shown in FIG29. The difference is that the current flow path when charging the second battery 52 includes: charger, Type C port 78, first connecting board 551, laser welding point of first circuit board 31 and flexible circuit board 35b, flexible circuit board 35b, laser welding point of flexible circuit board 35b and second circuit board 32, charging chip 61 on second circuit board 32, protection board of second battery 52, electrode of second battery 52 and cell of second battery 52.

[0144] In this embodiment, the speaker 77 is connected to the third circuit board 33 via the fifth connecting plate 555.

[0145] Please refer to Figure 31, which is a schematic diagram of the internal component distribution of the terminal device 100c provided in some other embodiments of this application. In the embodiment shown in Figure 31, the terminal device 100c is divided into a first folding area 11, a first hinge area 21, a second folding area 12, a second hinge area 22, a third folding area 13, a third hinge area 23, and a fourth folding area 14 connected in sequence. Multiple circuit boards include a first circuit board 31, a second circuit board 32, a third circuit board 33, and a fourth circuit board 34; the first circuit board 31 is located in the first folding area 11, the second circuit board 32 is located in the second folding area 12, the third circuit board 33 is located in the third folding area 13, and the fourth circuit board 34 is located in the fourth folding area 14; flexible circuit board. Flexible circuit board 35c passes through the first pivot area 21, the second folding area 12, the second pivot area 22, the third folding area 13, and the third pivot area 23, and is electrically connected to the first circuit board 31, the second circuit board 32, the third circuit board 33, and the fourth circuit board 34. Flexible circuit board 35c is electrically connected to the first circuit board 31 via laser welding, and / or to the second circuit board 32 via laser welding, and / or to the third circuit board 33 via laser welding, and / or to the fourth circuit board 34 via laser welding. The fourth folding area 14 is also correspondingly provided with a fourth battery 54, which is connected to the fourth circuit board 34 via a sixth connecting plate 556.

[0146] Please refer to Figures 32 to 39, which are schematic diagrams showing the internal component distribution of the terminal device 100d provided in other embodiments of this application. In the embodiments shown in Figures 9 and 29 to 31, a flexible circuit board 35 is used to electrically connect the circuit boards located in different folding areas. The main difference from the embodiments shown in Figures 9 and 29 to 31 is that in the embodiments shown in Figures 32 to 39, a rigid-flex board is used to achieve the electrical connection of the circuit boards in different folding areas. The terminal device 100d is divided into at least two folding areas and a hinge area located between two adjacent folding areas. The terminal device 100d includes multiple circuit boards, a charging chip 61, and a conductor 356. Each folding area is provided with at least one circuit board. At least one of the multiple circuit boards is a rigid-flex board, which includes a rigid part 36d and a flexible part 37d. The rigid part 36d is located in the folding area, and the flexible part 37d passes through the hinge area. The conductor 356 connects the flexible part 37d and the circuit boards other than the rigid-flex board. The conductor 356 is formed by laser welding. The charging chip 61 is disposed on at least one circuit board and electrically connected to the circuit board. The rigid-flex board is an integral structure, eliminating the need for additional electrical connection methods (such as laser welding, reflow soldering, BTB connection, etc.) to achieve electrical connection, which is equivalent to further reducing one transfer and further reducing the heat generated during charging. The terminal device 100d also includes a system-on-a-chip 62. When there is only one charging chip 61, the system-on-a-chip 62 and the charging chip 61 are disposed on the same circuit board. When there are multiple charging chips 61, the system-on-a-chip 62 and at least one charging chip 61 are disposed on the same circuit board.

[0147] It is understood that the technical features applicable to the embodiments shown in Figures 9, 29 to 31 can also be adapted to the embodiments shown in Figures 32 to 39, provided that the functions of the embodiments shown in Figures 32 to 39 can be achieved.

[0148] Referring to Figure 32, the terminal device 100d is divided into a first folding area 11, a first hinge area 21, and a second folding area 12 connected in sequence. Multiple circuit boards include a first circuit board 31d and a second circuit board 32d. The first circuit board 31d is a rigid-flex board, with a rigid portion 36d located in the first folding area 11 and a flexible portion 37d extending through the first hinge area 21 to the second folding area 12. The first circuit board 31d is approximately L-shaped. A charging chip 61 is disposed on and electrically connected to the rigid portion 36d. The second circuit board 32d is located in the second folding area 12; the flexible portion 37d is electrically connected to the second circuit board 32d via a conductor 356 formed by laser welding.

[0149] In this embodiment, the first circuit board 31d is a rigid-flex board, which does not require an additional electrical connection method to achieve electrical connection. Compared with the embodiment that uses a conductor 356 for electrical connection, this embodiment can further reduce the thickness of the electrical connection area and further reduce the resistance, thereby reducing the heat generated during charging.

[0150] In rigid-flex PCBs, the number of circuit layers located in the rigid section 36d is usually multiple, for example, three or more layers.

[0151] In some embodiments, an adhesive area 357 is provided at the end of the flexible plate portion 37d opposite to the rigid plate portion 36d. The adhesive area 357 is used to cooperate with the first traction piece 81, thereby playing an adhesive role in the steps of disassembling or assembling the rigid-flex plate, replacing the need to disassemble and assemble too many components in related technologies, and reducing the risk of component damage. In some embodiments, the rigid-flex plate includes a cavity 47 located in the flexible plate portion 37d, and the rigid-flex plate is bent in the region of the cavity 47.

[0152] Please refer to Figure 33. The difference between this embodiment and the one shown in Figure 32 is that in the terminal device 100e shown in Figure 33, the first circuit board 31e is located in the first folding area 11; the second circuit board 32e is a rigid-flex board, and the rigid part 36e is located in the second folding area 12. The charging chip 61 is disposed on the first circuit board 31e and electrically connected to the first circuit board 31e. The flexible part 37e passes through the first pivot area 21 and extends to the first folding area 11. The flexible part 37e and the first circuit board 31e are electrically connected to the conductor 356 formed by laser welding.

[0153] Please refer to Figure 34. The difference between this embodiment and the one shown in Figure 33 is that the terminal device 100f shown in Figure 34 includes a first circuit board 31f, a second circuit board 32f, and a third circuit board 33f. Both the second circuit board 32f and the third circuit board 33f are located in the second folding area 12, and both are rigid-flex boards. The rigid portion 36f of both the second circuit board 32f and the third circuit board 33f is located in the second folding area 12, and the flexible portion 37f of both the second circuit board 32f and the third circuit board 33f passes through the first pivot area 21 and extends to the first folding area 11, and is electrically connected to the first circuit board 31f after laser welding.

[0154] Referring to Figure 35, the terminal device 100g is divided into a first folding area 11, a first hinge area 21, a second folding area 12, a second hinge area 22, and a third folding area 13 connected in sequence. Multiple circuit boards include a first circuit board 31g, a second circuit board 32g, and a third circuit board 33g.

[0155] The first circuit board 31g is a rigid-flex board. The rigid part 36g is located in the first folding area 11, and the charging chip 61 is disposed on the rigid part 36g and electrically connected to the rigid part 36g. The flexible part 37g passes through the first hinge area 21, the second folding area 12, and the second hinge area 22 and extends to the third folding area 13. The flexible part 37g can pass through multiple hinge areas, which is beneficial to improving the quality of radio frequency signals; and it is also beneficial to reduce the number of BTBs, thereby improving the circuit layout area of ​​the rigid-flex board.

[0156] The second circuit board 32g is located in the second folding area 12, and the third circuit board 33g is located in the third folding area 13; the flexible board part 37g and the second circuit board 32g are electrically connected after laser welding, and the flexible board part 37g and the third circuit board 33g are electrically connected after laser welding.

[0157] Referring to Figure 36, the terminal device 100h is divided into a first folding area 11, a first hinge area 21, a second folding area 12, a second hinge area 22, and a third folding area 13 connected in sequence. Multiple circuit boards include a first circuit board 31h, a second circuit board 32h, and a third circuit board 33h. The first circuit board 31h is located in the first folding area 11, and the third circuit board 33h is located in the third folding area 13. The charging chip 61 is disposed on the first circuit board 31h and electrically connected to it. The second circuit board 32h is a rigid-flex board. The rigid portion 36h is located in the second folding area 12, and the flexible portion 37h penetrates the first hinge area 21 and extends to the first folding area 11, electrically connected to the first circuit board 31h. The flexible portion 37h also penetrates the second hinge area 22 and extends to the third folding area 13, electrically connected to the third circuit board 33h. The flexible circuit board 37h and the first circuit board 31h are electrically connected by a conductor 356 formed by laser welding, and the flexible circuit board 37h and the third circuit board 33h are electrically connected by a conductor 356 formed by laser welding.

[0158] Referring to Figure 37, the terminal device 100i is divided into a first folding area 11, a first hinge area 21, a second folding area 12, a second hinge area 22, and a third folding area 13 connected in sequence. Multiple circuit boards include a first circuit board 31i, a second circuit board 32i, and a third circuit board 33i. The first circuit board 31i is located in the first folding area 11, and the charging chip 61 is disposed on and electrically connected to the first circuit board 31i. The second circuit board 32i is located in the second folding area 12. The third circuit board 33i is a rigid-flex board, approximately Z-shaped, with a rigid portion 36i located in the third folding area 13 and a flexible portion 37i extending through the second hinge area 22, the second folding area 12, and the first hinge area 21, and reaching the first folding area 11. The flexible portion 37i and the first circuit board 31i are electrically connected by a conductor 356 formed by laser welding, and the flexible portion 37i and the second circuit board 32i are electrically connected by a conductor 356 formed by laser welding.

[0159] Referring to Figure 38, the terminal device 100j is divided into a first folding area 11, a first hinge area 21, a second folding area 12, a second hinge area 22, and a third folding area 13 connected in sequence. Multiple circuit boards include a first circuit board 31j, a second circuit board 32j, and a third circuit board 33j. Both the first circuit board 31j and the third circuit board 33j are rigid-flex boards; the first circuit board 31j is approximately L-shaped, and the third circuit board 33j is approximately Z-shaped. A charging chip 61 is disposed on the rigid portion 36j of the first circuit board 31j and electrically connected to the rigid portion 36j. The second circuit board 32j is located in the second folding area 12. The flexible portion 37j of the first circuit board 31j extends through the first hinge area 21 to the second folding area 12 and is electrically connected to the second circuit board 32j. The flexible portion 37j of the third circuit board 33j extends through the second hinge area 22 to the second folding area 12 and is electrically connected to the flexible portion 37j of the first circuit board 31j. The flexible circuit board portion 37j of the first circuit board 31j and the second circuit board 32j are electrically connected by a conductor 356 formed by laser welding. The flexible circuit board portion 37j of the third circuit board 33j and the flexible circuit board portion 37j of the first circuit board 31j are electrically connected by a conductor 356 formed by laser welding.

[0160] Referring to Figure 39, the terminal device 100k is divided into a first folding area 11, a first hinge area 21, a second folding area 12, a second hinge area 22, and a third folding area 13 connected in sequence. Multiple circuit boards include a first circuit board 31k, a second circuit board 32k, and a third circuit board 33k. The first circuit board 31k is located in the first folding area 11, and the charging chip 61 is disposed on and electrically connected to the first circuit board 31k. The second circuit board 32k and the third circuit board 33k are both rigid-flex boards, and both are approximately Z-shaped. The rigid portion 36k of the second circuit board 32k is located in the second folding area 12, and the rigid portion 36j of the third circuit board 33k is located in the third folding area 13; the flexible portion 37k of the second circuit board 32k passes through the first pivot area 21 and extends to the first folding area 11 and is electrically connected to the first circuit board 31k, and the flexible portion 37k of the third circuit board 33k passes through the second pivot area 22 and extends to the second folding area 12 and is electrically connected to the second circuit board 32k; wherein, the flexible portion 37k of the second circuit board 32k and the first circuit board 31k are electrically connected by a conductor 356 formed by laser welding, and the flexible portion 37k of the third circuit board 33k and the second circuit board 32k are electrically connected by a conductor 356 formed by laser welding.

[0161] Please refer to Figures 40 and 41. Figure 40 is a cross-sectional schematic diagram of a rigid-flex plate provided in some embodiments of this application; Figure 41 is a flowchart of the process of manufacturing the rigid-flex plate shown in Figure 40.

[0162] In this embodiment, the rigid-flex board includes two rigid sections 361 and one flexible section 371. The flexible section 371 is located between the two rigid sections 361. The flexible section 371 has two circuit layers, and the rigid section 361 has eight circuit layers. The design parameters of the rigid-flex board can be found in the table below.

[0163] The rigid-flex board of this embodiment can be manufactured using the flowchart shown in Figure 41. This generally includes: cutting a specific area or layer of the incoming material; forming positioning holes in a predetermined area for precise alignment in subsequent processes; changing tools or adjusting process parameters as needed during the processing of rigid materials such as FR4; pre-processing the incoming polypropylene (PP); forming positioning holes in a predetermined area of ​​the incoming flexible circuit board material and fabricating circuitry to obtain the desired circuit pattern; attaching a pre-drilled cover film to the semi-finished product with the circuit pattern and pressing it together with the polypropylene and rigid material to form through-holes; increasing the thickness of the copper layer through copper plating and plate electroplating to obtain a circuit pattern of suitable thickness; etching the circuit pattern in a specific area to obtain the circuit layer; forming a solder resist layer (i.e., solder mask) on the surface of the circuit layer and then performing surface treatment, opening treatment, and shaping treatment to expose the area for subsequent electrical connections, thus obtaining the flexible circuit board; and conducting electrical performance tests and other performance tests on the flexible circuit board. After passing the tests, it is packaged to obtain the final product.

[0164] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A terminal device divided into at least two folding regions and a hinge region between two adjacent folding regions, characterized in that, The terminal device comprises: a plurality of circuit boards, at least one of which is arranged in each of the folding regions; a flexible circuit board which extends through the hinge region and connects at least two of the plurality of circuit boards; a conductive body which connects the flexible circuit board and the circuit board, the conductive body being formed by laser welding; a screen, the region in which the flexible circuit board is electrically connected to the circuit board being on the side of the circuit board which faces away from the screen; and a plurality of batteries, one of which is arranged in each of the folding regions and is electrically connected to the circuit board in the same folding region.

2. The terminal device of claim 1, wherein, The terminal device is divided into a first folding region, a first hinge region and a second folding region which are connected in sequence, the plurality of circuit boards comprising a first circuit board and a second circuit board; the first circuit board is located in the first folding region, and the second circuit board is located in the second folding region; the flexible circuit board extends through the first hinge region and electrically connects the first circuit board and the second circuit board; the flexible circuit board is electrically connected to the first circuit board after laser welding, and / or the flexible circuit board is electrically connected to the second circuit board after laser welding.

3. The terminal device of claim 1, wherein, The terminal device is divided into a first folding region, a first hinge region, a second folding region, a second hinge region and a third folding region which are connected in sequence, the plurality of circuit boards comprising a first circuit board, a second circuit board and a third circuit board; the first circuit board is located in the first folding region, the second circuit board is located in the second folding region, and the third circuit board is located in the third folding region; the flexible circuit board extends through the first hinge region, the second folding region and the second hinge region and electrically connects the first circuit board, the second circuit board and the third circuit board; the flexible circuit board is electrically connected to the first circuit board after laser welding, and / or the flexible circuit board is electrically connected to the second circuit board after laser welding, and / or the flexible circuit board is electrically connected to the third circuit board after laser welding.

4. The terminal device of claim 1, wherein, The terminal device is divided into a first folding region, a first hinge region, a second folding region, a second hinge region, a third folding region, a third hinge region and a fourth folding region which are connected in sequence, the plurality of circuit boards comprising a first circuit board, a second circuit board, a third circuit board and a fourth circuit board; the first circuit board is located in the first folding region, the second circuit board is located in the second folding region, the third circuit board is located in the third folding region, and the fourth circuit board is located in the fourth folding region; the flexible circuit board extends through the first hinge region, the second folding region, the second hinge region, the third folding region and the third hinge region and electrically connects the first circuit board, the second circuit board, the third circuit board and the fourth circuit board; the flexible circuit board is electrically connected to the first circuit board after laser welding, and / or the flexible circuit board is electrically connected to the second circuit board after laser welding, and / or the flexible circuit board is electrically connected to the third circuit board after laser welding, and / or the flexible circuit board is electrically connected to the fourth circuit board after laser welding.

5. The terminal device according to any one of claims 2 to 4, characterized in that, The flexible circuit board comprises a first body and a first pad, the first pad comprises a through portion and an extension portion, the through portion penetrates the first body and forms a first through hole, and the extension portion is located at both ends of the through portion and on the surface of the first body; the first circuit board comprises a second body and a second pad, the second pad is located on the surface of the second body; and the conductive body is located in the first through hole and connected with the first pad and the second pad.

6. The terminal device according to any one of claims 2 to 4, characterized in that, The flexible circuit board comprises a first body and a first pad, the first pad penetrates the first body and forms a first through hole; the first circuit board comprises a second body and a second pad, the second pad penetrates the second body and forms a second through hole; and the conductive body is accommodated in the first through hole and the second through hole, and is also located between the first body and the second body.

7. The terminal device according to any one of claims 1 to 6, characterized in that, The terminal device further comprises a system chip and a charging chip, and the system chip and the charging chip are arranged on the same circuit board.

8. The terminal device according to any one of claims 1 to 7, characterized in that, Both ends of the flexible circuit board are provided with an adhesive area, which plays an adhesive role in the steps of disassembling or assembling the flexible circuit board.

9. The terminal device according to any one of claims 1 to 8, characterized by, The flexible circuit board comprises a cavity, and the flexible circuit board is bent in the area of the cavity.

10. A terminal device divided into at least two folding regions and a hinge region located between two adjacent folding regions, characterized in that, The terminal device comprises: A plurality of circuit boards, at least one of the circuit boards is a rigid-flexible combined board, the rigid-flexible combined board comprises a rigid board portion and a flexible board portion, the rigid board portion is located in the folding area, and the flexible board portion penetrates the rotating shaft area; A conductive body, which connects the flexible board portion and the circuit board other than the rigid-flexible combined board, and is formed by laser welding; and A plurality of batteries, each of the folding areas is provided with the battery, and the battery is electrically connected with the circuit board located in the same folding area.

11. The terminal device according to claim 10, characterized by The terminal device is divided into a first folding area, a first rotating shaft area and a second folding area connected in sequence, the plurality of circuit boards comprise a first circuit board and a second circuit board; the first circuit board is a rigid-flexible combined board, the rigid board portion is located in the first folding area; the flexible board portion penetrates the first rotating shaft area and extends to the second folding area, and the second circuit board is located in the second folding area; and the flexible board portion is electrically connected with the second circuit board after laser welding.

12. The terminal device of claim 10, wherein, The terminal device is divided into a first folding area, a first rotating shaft area and a first folding area connected in sequence, the plurality of circuit boards comprise a first circuit board and a second rigid-flexible combined board; the first circuit board is located in the first folding area; the second circuit board is a rigid-flexible combined board, the rigid board portion is located in the second folding area, the flexible board portion penetrates the first rotating shaft area and extends to the first folding area, and the flexible board portion is electrically connected with the first circuit board after laser welding.

13. The terminal device of claim 12, wherein, The plurality of circuit boards further comprise a third circuit board, the third circuit board is located in the second folding area, the third circuit board is a rigid-flexible combined board, the flexible board portion of the third circuit board penetrates the first rotating shaft area and extends to the first folding area, and is electrically connected with the first circuit board after laser welding.

14. The terminal device of claim 10, wherein, The terminal device is divided into a first folding area, a first rotating shaft area, a second folding area, a second rotating shaft area and a third folding area connected in sequence, the plurality of circuit boards include a first circuit board, a second circuit board and a third circuit board, the first circuit board is a rigid-flex board, and the hard board part is located in the first folding area; the second circuit board is located in the second folding area, and the third circuit board is located in the third folding area; the soft board part penetrates through the first rotating shaft area, the second folding area and the second rotating shaft area and extends to the third folding area, and the soft board part and the second circuit board are electrically connected after laser welding, and the soft board part and the third circuit board are electrically connected after laser welding.

15. The terminal device of claim 10, wherein, The terminal device is divided into a first folding area, a first rotating shaft area, a second folding area, a second rotating shaft area and a third folding area connected in sequence, the plurality of circuit boards include a first circuit board, a second circuit board and a third circuit board; the first circuit board is located in the first folding area, and the third circuit board is located in the third folding area; the second circuit board is a rigid-flex board, and the hard board part is located in the second folding area; the soft board part penetrates through the first rotating shaft area and extends to the first folding area and is electrically connected with the first circuit board, and the soft board part also penetrates through the second rotating shaft area and extends to the third folding area and is electrically connected with the third circuit board; the soft board part and the first circuit board are electrically connected after laser welding, and the soft board part and the third circuit board are electrically connected after laser welding.

16. The terminal device of claim 10, wherein, The terminal device is divided into a first folding area, a first rotating shaft area, a second folding area, a second rotating shaft area and a third folding area connected in sequence, the plurality of circuit boards include a first circuit board, a second circuit board and a third circuit board; the first circuit board is located in the first folding area, and the second circuit board is located in the second folding area; the third circuit board is a rigid-flex board, and the hard board part is located in the third folding area; the soft board part penetrates through the second rotating shaft area, the second folding area and the first rotating shaft area and extends to the first folding area; the soft board part and the first circuit board are electrically connected after laser welding, and the soft board part and the second circuit board are electrically connected after laser welding.

17. The terminal device of claim 10, wherein, The terminal device is divided into a first folding area, a first rotating shaft area, a second folding area, a second rotating shaft area and a third folding area connected in sequence, the plurality of circuit boards include a first circuit board, a second circuit board and a third circuit board; the first circuit board and the third circuit board are both rigid-flex boards, and the second circuit board is located in the second folding area; the soft board part of the first circuit board penetrates through the first rotating shaft area, extends to the second folding area and is electrically connected with the second circuit board, and the soft board part of the third circuit board penetrates through the second rotating shaft area and extends to the second folding area and is electrically connected with the soft board part of the first circuit board; the soft board part of the first circuit board and the second circuit board are electrically connected after laser welding, and the soft board part of the third circuit board and the soft board part of the first circuit board are electrically connected after laser welding.

18. The terminal device of claim 10, wherein, The terminal device is divided into a first folding area, a first rotating shaft area, a second folding area, a second rotating shaft area and a third folding area connected in sequence, the plurality of circuit boards include a first circuit board, a second circuit board and a third circuit board; the first circuit board is located in the first folding area; the second circuit board and the third circuit board are both rigid-flexible boards, the rigid board part of the second circuit board is located in the second folding area, and the rigid board part of the third circuit board is located in the third folding area; the flexible board part of the second circuit board penetrates through the first rotating shaft area and extends to the first folding area to be electrically connected with the first circuit board, and the flexible board part of the third circuit board penetrates through the second rotating shaft area and extends to the second folding area to be electrically connected with the second circuit board; wherein the flexible board part of the second circuit board and the first circuit board are electrically connected after laser welding, and the flexible board part of the third circuit board and the second circuit board are electrically connected after laser welding.

19. The terminal device according to any one of claims 10-18, characterized by, The terminal device further includes a system-level chip and a charging chip, and the system-level chip and the charging chip are arranged on the same circuit board.

20. The terminal device according to any one of claims 10-19, characterized by, An end part of the flexible board part away from the rigid board part is provided with an adhesive area, and the adhesive area is used for adhesion in the steps of disassembling or assembling the rigid-flexible board.

21. The terminal device according to any one of claims 10-20, characterized by, The rigid-flexible board includes a cavity, the cavity is located in the flexible board part, and the rigid-flexible board is bent in the area of the cavity.

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