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 claims priority from a Chinese patent application filed on July 22, 2024, with the application number 202410985650.X and the title of "Terminal device", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of terminal devices, and in particular to a terminal device. BACKGROUND

[0004] Folding screen phones and other foldable terminal devices have the advantages of good viewing experience and wide field of view, and are increasingly favored by users. Among them, the terminal device will generate a lot of heat during charging, and as users demand thinner terminal devices, the heat that users can feel will be more obvious, affecting the user experience. SUMMARY

[0005] Therefore, it is necessary to provide a terminal device that can reduce the degree of user temperature perception during charging to solve the above technical problems.

[0006] In a first aspect, an embodiment of the present application provides a terminal device divided into at least two folding areas and a hinge area between the adjacent two folding areas, the terminal device comprising a plurality of circuit boards, a flexible circuit board, a conductive body, a screen and a plurality of batteries. Each folding area is provided with at least one circuit board; the flexible circuit board penetrates the hinge area and connects at least two of the plurality of circuit boards; the conductive body connects the flexible circuit board and the circuit board, and the conductive body is formed by laser welding; the region where the flexible circuit board is electrically connected with the circuit board is located on the side of the circuit board away from the screen; each folding area is provided with a battery, and the battery is electrically connected with the circuit board located in the same folding area.

[0007] In the above structure design, the flexible circuit board and the circuit board are connected by laser welding, which is conducive to reducing the thickness of the electrical connection area, which is equivalent to increasing the distance from the electrical connection area to the outer surface of the terminal device, i.e., during charging, the distance between the user and the heat source can be increased, which is conducive to reducing the temperature perceived by the user; in addition, laser welding is used for direct electrical connection, which is conducive to reducing the number of connections, reducing the current flow path, and reducing the resistance, thereby reducing the heat generated during charging, and further reducing the temperature perceived by the user. Laser welding is used instead of BTB connection, the flexible circuit board is thinner, which is conducive to the disassembly of the flexible circuit board, and can reduce the number of elements to be removed and reduce the risk of damaging the elements.

[0008] In a possible implementation, the terminal device is divided into a first folding area, a first rotating shaft area and a second folding area connected in sequence, and the plurality of circuit boards include 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; the flexible circuit board penetrates through the first rotating shaft area and is electrically connected with the first circuit board and the second circuit board; the flexible circuit board is electrically connected with the first circuit board after laser welding, and / or the flexible circuit board is electrically connected with the second circuit board after laser welding.

[0009] In the above structure design, for a possible implementation of a two-fold terminal device, the flexible circuit board is used to realize electrical connection of the two folding areas through laser welding, which can increase the distance between the user and the heat source during charging, is conducive to reducing the temperature felt by the user, is conducive to reducing the number of switching, and reducing the heat generated during charging, and is conducive to disassembly of the flexible circuit board.

[0010] In a possible implementation, 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, and 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 is located in the second folding area, and the third circuit board is located in the third folding area; the flexible circuit board penetrates through the first rotating shaft area, the second folding area and the second rotating shaft area and is electrically connected with the first circuit board, the second circuit board and the third circuit board; the flexible circuit board is electrically connected with the first circuit board after laser welding, and / or the flexible circuit board is electrically connected with the second circuit board after laser welding, and / or the flexible circuit board is electrically connected with the third circuit board after laser welding.

[0011] In the above structure design, for a possible implementation of a three-fold terminal device, the flexible circuit board can pass through a plurality of rotating shaft areas, which is conducive to improving the quality of the radio frequency signal, and is conducive to reducing the number of BTBs, and further conducive to improving the layout area of the flexible circuit board; the flexible circuit board is used to realize electrical connection of the two folding areas through laser welding, which can increase the distance between the user and the heat source during charging, is conducive to reducing the temperature felt by the user, is conducive to reducing the number of switching, and reducing the heat generated during charging, and is conducive to disassembly of 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 a possible implementation, 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.

[0019] In a possible implementation, the terminal device is designed as above.

[0020] In a possible implementation, the two ends of the flexible circuit board are provided with adhesive areas, which are used for adhesion in the process of disassembling or assembling the flexible circuit board.

[0021] In a possible implementation, the terminal device is designed as above.

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

[0023] In a possible implementation, the terminal device is designed as above.

[0024] In a second aspect, the embodiments of the present application provide a terminal device, which is divided into at least two folding areas and a rotating shaft area between the adjacent two folding areas. The terminal device comprises a plurality of circuit boards, a conductive body and a charging chip. Each folding area is provided with at least one circuit board, and at least one circuit board in the plurality of circuit boards is a rigid-flexible combined board. The rigid-flexible combined board comprises a rigid board part and a flexible board part. The rigid board part is located in the folding area, and the flexible board part penetrates through the rotating shaft area. The conductive body connects the flexible board part and the circuit board other than the rigid-flexible combined board, and the conductive body is formed by laser welding. Each folding area is provided with a battery, and the battery is electrically connected with the circuit board located in the same folding area.

[0025] In a possible implementation, the terminal device is designed as above.

[0026] In a possible implementation, the terminal device is divided into a first folding area, a first rotating shaft area and a second folding area connected in sequence, and the plurality of circuit boards include a first circuit board and a second circuit board; the first circuit board is a rigid-flexible combined board, and the rigid board part is located in the first folding area; the soft board part penetrates through the first rotating shaft area and extends to the second folding area, and the second circuit board is located in the second folding area; the soft board part is electrically connected to the second circuit board after laser welding.

[0027] The above structure is a possible implementation of a two-fold terminal device, and the soft board part of the rigid-flexible combined board is used to realize electrical connection of multiple folding areas. The rigid-flexible combined board is an integral structure, and no additional electrical connection mode is needed to realize electrical connection, which is equivalent to further reducing the number of relays and further reducing the heat generated during charging.

[0028] In a possible implementation, the terminal device is divided into a first folding area, a first rotating shaft area and a second folding area connected in sequence, and the plurality of 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-flexible combined board, and the rigid board part is located in the second folding area, and the soft board part penetrates through the first rotating shaft area and extends to the first folding area; the soft board part is electrically connected to the first circuit board after laser welding. The above structure is a possible implementation of a two-fold terminal device.

[0029] In a possible implementation, the plurality of circuit boards further include 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 soft board part of the third circuit board penetrates through the first rotating shaft area and extends to the first folding area, and is electrically connected to the first circuit board after laser welding. The above structure is a possible implementation of a three-fold terminal device, and at least two circuit boards can be rigid-flexible combined boards.

[0030] In a possible implementation, 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, and 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-flexible combined board, and the rigid 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; the soft board part is electrically connected to the second circuit board after laser welding, and the soft board part is electrically connected to the third circuit board after laser welding. In the above structure, the soft board part can pass through multiple rotating shaft areas, which is conducive to improving the quality of radio frequency signals, and is conducive to reducing the number of BTBs, and further conducive to improving the layout area of the rigid-flexible combined board.

[0031] In a possible implementation, 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, and 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, a rigid board part is located in the second folding area, a flexible board part extends to the first circuit board in the first folding area through the first rotating shaft area, and the flexible board part extends to the third circuit board in the third folding area through the second rotating shaft area; the flexible board part and the first circuit board are electrically connected after laser welding, and the flexible board part and the third circuit board are electrically connected after laser welding. The above structure is a possible implementation of a three-fold terminal device, the flexible board part can pass through a plurality of rotating shaft areas, which is conducive to improving the quality of radio frequency signals, and is conducive to reducing the number of BTBs, and thus is conducive to improving the layout area of the rigid-flex board.

[0032] In a possible implementation, 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, and 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, a rigid board part is located in the third folding area, and a flexible board part extends to the first folding area through the second rotating shaft area and the second folding area; the flexible board part and the first circuit board are electrically connected after laser welding, and the flexible board part and the second circuit board are electrically connected after laser welding. The above structure is a possible implementation of a three-fold terminal device.

[0033] In a possible implementation, 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, and 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; a flexible board part of the first circuit board extends to the second folding area through the first rotating shaft area and is electrically connected with the second circuit board, and a flexible board part of the third circuit board extends to the second folding area through the second rotating shaft area and is electrically connected with the flexible board part of the first circuit board; the flexible board part of the first circuit board and the second circuit board are electrically connected after laser welding, and the flexible board part of the third circuit board and the flexible board part of the first circuit board are electrically connected after laser welding. The above structure is a possible implementation of a three-fold terminal device.

[0034] In a possible implementation, 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, and 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-flex 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 soft 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 soft 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 soft board part of the second circuit board and the first circuit board are electrically connected after laser welding, and the soft board part of the third circuit board and the second circuit board are electrically connected after laser welding. The above structural design is a possible implementation of a three-fold terminal device.

[0035] In a possible implementation, the terminal device further includes a system chip and a charging chip, and the system chip and the charging chip are arranged on the same circuit board.

[0036] In a possible implementation, the end part of the soft 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-flex board.

[0037] In the above structural design, the adhesive area is provided at the end part of the soft board part of the rigid-flex board, and is used for cooperation with the first traction piece and the second traction piece, and is further used for adhesion in the steps of disassembling or assembling the rigid-flex board, thereby reducing the risk of damage to elements due to the need to remove or assemble too many elements.

[0038] In a possible implementation, the rigid-flex board includes a cavity, and the cavity is located in the soft board part, and the rigid-flex board is bent in the area of the cavity. In the above structural design, the cavity is provided, which is beneficial to the bending of the rigid-flex board. BRIEF DESCRIPTION OF DRAWINGS

[0039] FIG. 1 is a schematic diagram of the internal element distribution of a terminal device provided by the related art.

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

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

[0042] FIG. 4 is a schematic diagram of heat generation of a mobile phone in a charging process provided by the related art.

[0043] FIG. 5 is a schematic diagram of the structure of a board-to-board connector electrically connected provided by the related art.

[0044] FIG. 6 is a structural schematic diagram of a terminal device according to an embodiment of the present application.

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

[0046] FIG. 8 is a distribution schematic diagram of internal elements of the terminal device according to an embodiment of the present application.

[0047] FIG. 9 is a distribution schematic diagram of internal elements of the terminal device from another direction according to an embodiment of the present application.

[0048] FIG. 10 is a cross-sectional schematic diagram of the terminal device in an unfolded state according to an embodiment of the present application.

[0049] FIG. 11 is a cross-sectional schematic diagram of the terminal device in a folded state according to an embodiment of the present application.

[0050] FIG. 12 is a structural schematic diagram of the first circuit board and the flexible circuit board after being connected according to an embodiment of the present application.

[0051] FIG. 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 the present application.

[0052] FIG. 14 is a structural schematic diagram of the first circuit board and the flexible circuit board connected by laser welding according to an embodiment of the present application.

[0053] FIG. 15 is a schematic diagram of the connection of the first circuit board and the flexible circuit board according to another embodiment of the present application.

[0054] FIG. 16 is a structural comparison schematic diagram of the connection of the first circuit board and the flexible circuit board by a board-to-board connector and laser welding, respectively.

[0055] FIG. 17 is a top view schematic diagram of the terminal device according to an embodiment of the present application.

[0056] FIG. 18A is a cross-sectional schematic diagram of a partial area of the terminal device according to another embodiment.

[0057] FIG. 18B is a cross-sectional schematic diagram of a partial area of the terminal device shown in FIG. 17 along the direction of I-I.

[0058] FIG. 18C is a cross-sectional schematic diagram of a partial area of the terminal device according to another embodiment of the present application.

[0059] FIG. 19 is a cross-sectional flow schematic diagram of the adhesion of the first traction sheet on the flexible circuit board according to an embodiment of the present application.

[0060] FIG. 20 is a top view flow schematic diagram of the adhesion of the first traction sheet and the second traction sheet on the flexible circuit board according to an embodiment of the present application.

[0061] Figure 21 is a cross-sectional flow diagram illustrating the disassembly of a flexible circuit board from a terminal device using a first pulling tab and a second pulling tab according to some embodiments of the present application.

[0062] Figure 22 is a cross-sectional flow diagram illustrating the assembly of a flexible circuit board into a terminal device using a first pulling tab and a second pulling tab according to some embodiments of the present application.

[0063] Figure 23 is a cross-sectional diagram illustrating a flexible circuit board according to some embodiments of the present application.

[0064] Figure 24 is a cross-sectional diagram illustrating a flexible circuit board according to some other embodiments of the present application.

[0065] Figure 25A is a top view diagram illustrating a flexible circuit board according to some embodiments of the present application.

[0066] Figure 25B is a top view diagram illustrating a flexible circuit board according to some other embodiments of the present application.

[0067] Figure 26 is a cross-sectional diagram illustrating a flexible circuit board according to some embodiments of the present application.

[0068] Figure 27A is a diagram illustrating a structure of a first pad of a flexible circuit board according to some embodiments of the present application.

[0069] Figure 27B is a diagram illustrating a structure of a first pad of a flexible circuit board according to some other embodiments of the present application.

[0070] Figure 28 is a diagram illustrating a connection of a circuit layer according to some embodiments of the present application.

[0071] Figures 29-39 are diagrams illustrating internal element distributions of a terminal device according to some other embodiments of the present application.

[0072] Figure 40 is a cross-sectional diagram illustrating a rigid-flexible combined board according to some embodiments of the present application.

[0073] Figure 41 is a flow diagram illustrating a process of manufacturing the rigid-flexible combined board of Figure 40.

[0074] Explanation of main element symbols

[0075] Terminal device: 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 rotating shaft area: 21, 21'; second rotating shaft area: 22; third rotating shaft area: 23; first circuit board: 31, 31', 31d, 31e, 31f, 31g, 31h, 31i, 31j, 31k; female pad: 311'; second body: 312; second pad: 313; second through hole: 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 pad: 351'; adhesive layer: 352'; reinforcing member: 353'; first body: 354; first pad: 355; through portion: 3551; extension portion: 3552; first through hole: 3553; conductive body: 356; bonding area: 357; hard plate portion: 36d, 36e, 36f, 36g, 36h, 36i, 36j, 36k, 361; soft plate portion: 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 wire: 452-1, 452-2; cover layer: 46; cavity: 47; battery: 50'; first battery: 51; second battery: 52; third battery: 53; fourth battery: 54; first connecting plate: 551, 551'; second connecting plate: 552; third connecting plate: 553, 553'; fourth connecting plate: 554; fifth connecting plate: 555; sixth connecting plate: 556; charger: 561'; protection plate: 562'; charging chip: 61, 61'; system-level chip: 62, 62'; PAMiD: 621; radio frequency switch: 622; universal flash storage: 63, 63'; electronic component: 64; shielding frame: 65; screen: 71; middle frame: 72; recess: 721; appearance cover: 73; support plate: 74; fixing block: 75; reinforcing plate: 76; speaker: 77; Type C port: 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: 882; force: F1, F2; first direction: L1; second direction: L2; third direction: L3. DETAILED DESCRIPTION

[0076] Referring to FIG. 1, FIG. 1 is a schematic diagram of internal elements distribution of a terminal device 100' provided by the related art. 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', and the first hinge area 21' connects 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 charge IC 61', a System on a Chip (SOC) 62', and the like. 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 hinge area 21' and electrically connects the first circuit board 31' and the second circuit board 32'. The battery 50' is electrically connected with the first circuit board 31', and the charge IC 61' and the SOC 62' are both arranged on the first circuit board 31'.

[0078] Referring to FIGS. 2, 3 and 4, FIG. 2 is a schematic diagram of connection principle of a charger 561' of a mobile phone and the mobile phone provided by the related art, FIG. 3 is a schematic diagram of connection principle of the charger 561', a radio frequency chip and the battery 50' of the mobile phone provided by the related art, and FIG. 4 is a schematic diagram of heat generation of the mobile phone in a charging process provided by the related art.

[0079] In the charging process, alternating current passes through the charger 561', the first circuit board 31', the charge IC 61' and the SOC 62' connected to the circuit board, a protection board 562', and the battery 50' in sequence. In which, when the alternating current passes through the charge IC 61' and the SOC 62', the charge IC 61' and the SOC 62' work to generate heat; when the alternating current passes through the protection board 562', electronic elements (including MOS) in the protection board 562' work to generate heat; and when the alternating current passes through the battery 50', heat is generated when passing through the tab, the electrode and the battery material in sequence, that is, in the charging process, the terminal device 100' generates a certain amount of heat. Due to the structure design of thinning of the terminal device 100', the installation space in the terminal device 100' is limited, and the charge IC 61' and the SOC 62' are very close to the outer surface of the terminal device 100'. If the heat is concentrated during the charging process, and when the user holds the terminal device 100', the user experience is affected.

[0080] Referring to FIG. 5, FIG. 5 is a schematic diagram of structure of a Board to Board (BTB) electrical connection provided by the related art.

[0081] The electrical connection 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' is usually achieved by a BTB. 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 welded on the first circuit board 31', and the female solder pad 311' is arranged on the surface of the first circuit board 31' along the thickness direction of the first circuit board 31'; a male solder pad 351' is welded on the flexible circuit board 35', and the male solder pad 351' is arranged on the surface of the flexible circuit board 35' along the thickness direction of the flexible circuit board 35'. The male solder pad 351' is inserted into the female solder pad 311', thereby 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' away from the male solder pad 351' usually further sequentially has a glue layer 352' and a reinforcing member 353', the glue layer 352' bonds the reinforcing member 353' and the flexible circuit board 35', and is used for increasing the strength of the flexible circuit board 35' and facilitating the insertion of the male solder pad 351' provided on the flexible circuit board 35' into the female solder pad 311'.

[0082] After the electrical connection between the first circuit board 31' and the flexible circuit board 35', the overall thickness of the first circuit board 31' and the flexible circuit board 35' after the connection is increased, and the increased thickness is the thickness of the male solder pad 351' and the female solder pad 311' after the connection and the fitting gap between the male solder pad 351' and the female solder pad 311', which is not conducive to the structure design of the thin and light terminal device 100'. In addition, the electrical connection by the BTB is equivalent to increasing the number of switching between the first circuit board 31' and the flexible circuit board 35', which is not conducive to the signal transmission. Usually, in order to ensure the stability of the insertion of the male solder pad 351' and the female solder pad 311', the area of the male solder pad 351' and the female solder pad 311' is relatively large, thereby reducing the wiring area of the first circuit board 31' and the flexible circuit board 35'. The male solder pad 351' is fixed on the flexible circuit board 35', and if the flexible circuit board 35' needs to be replaced or repaired, the corresponding structures in the terminal device 100' need to be removed, which increases the cost, and there is a risk of damaging other elements during the removal or reassembly. Therefore, it is necessary to improve the above technology.

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

[0084] In the embodiments shown in FIG. 6 and FIG. 7, the terminal device 100 is a folding screen mobile phone. The folding screen mobile phone is favored by users, and the folding screen mobile phone has a good viewing experience, a wide field of view, and supports functions such as split screen and double screen operation, which can bring a good user experience in both games and daily use. In other embodiments, the terminal device 100 can also be a notebook computer, a smart watch, or other foldable electronic products. The terminal device 100 is divided into at least two folding areas and a hinge area between adjacent two folding areas, and the number of hinge areas is related to the number of folding areas.

[0085] The terminal device 100 is divided into at least two folding areas and a hinge area between adjacent two folding areas, and the folding areas can be switched between a folded state and an unfolded state through the action of the hinge area. The terminal device 100 includes a plurality of circuit boards and electronic elements disposed on the circuit boards, including but not limited to processors, antenna modules, Bluetooth modules, WiFi modules, GPS modules, power supplies, charging modules, screen display and operation modules, etc.

[0086] Please refer to FIG. 8, FIG. 9, FIG. 10 and FIG. 11, FIG. 8 is a schematic diagram of the internal element distribution of the terminal device 100 provided by the embodiment of the application, FIG. 9 is a schematic diagram of the internal element distribution of the terminal device 100 provided by the embodiment of the application in another orientation, FIG. 10 is a schematic diagram of the cross section of the terminal device 100 in an unfolded state provided by the embodiment of the application, and FIG. 11 is a schematic diagram of the cross section of the terminal device 100 in a folded state provided by the embodiment of the application.

[0087] In this embodiment, the terminal device 100 is divided into two folding areas and a hinge area, which are respectively named as the first folding area 11, the second folding area 12 and the first hinge area 21. The first hinge area 21 connects the first folding area 11 and the second folding area 12, and the first folding area 11 and the second folding area 12 can be switched between a folded state and an unfolded state through the action of the first hinge area 21. Among them, 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 each other through the first hinge area 21, which is the folded state of the terminal device 100.

[0088] For the convenience of description, a first direction L1, a second direction L2 and a third direction L3 perpendicular to each other are defined, the first direction L1 is a direction in which the first folding area 11, the second folding area 12 and the first rotating shaft area 21 are arranged in sequence when the terminal device 100 is in the unfolded state, the second direction L2 is a direction of the rotating shaft of the first folding area 11 and the second folding area 12, and the third direction L3 is a 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 can be understood that in the actual terminal device 100, the first direction L1, the second direction L2 and the third direction L3 are not limited to be perpendicular to each other, and can be adjusted according to the specific terminal device 100, that is, even if they are designed to be perpendicular to each other, a certain tolerance (for example, ±1%) is allowed.

[0089] Please refer to FIG. 9 again, the terminal device 100 includes a first circuit board 31, a second circuit board 32 and a flexible circuit board 35, etc. 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 rotating shaft area 21 and electrically connects the first circuit board 31 and the second circuit board 32. Among them, the flexible circuit board 35 is electrically connected with the first circuit board 31 after laser welding, and / or the flexible circuit board 35 is electrically connected with the second circuit board 32 after laser welding. In this embodiment, the flexible circuit board 35 is electrically connected with the first circuit board 31 after laser welding, and the flexible circuit board 35 is electrically connected with the second circuit board 32 after laser welding.

[0090] The terminal device 100 includes a screen 71, two middle frames 72 and an appearance cover 73. The screen 71 is a folding screen, the screen 71 is located in the first folding area 11, the rotating shaft area and the second folding area 12, the two middle frames 72 are respectively located in the first folding area 11 and the second folding area 12, and the appearance cover 73 is located in the first rotating shaft area 21. Taking the terminal device 100 in the unfolded state as an example, the area where the first circuit board 31 and the flexible circuit board 35 are electrically connected is stacked along the third direction L3 and is parallel to the screen 71, and the area where the flexible circuit board 35 is electrically connected with the first circuit board 31 is located on the side of the first circuit board 31 away from the screen 71.

[0091] Please refer to FIG. 12, FIG. 13 and FIG. 14, FIG. 12 is a structure schematic diagram of the first circuit board 31 and the flexible circuit board 35 after connection provided by the embodiment of the application, FIG. 13 is a cross-sectional schematic diagram of the first circuit board 31 and the flexible circuit board 35 connected by the conductive body 356 provided by the embodiment of the application, and FIG. 14 is a structure schematic diagram of laser welding of the first circuit board 31 and the flexible circuit board 35 provided by the embodiment of the 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] The 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 which is the housing part of the rotating shaft, the first pad 355 of the flexible circuit board 35 is corresponding to the conductive paste 87 which is exposed to the first through hole 3553, the part of the flexible circuit board 35 which needs to be welded with the first circuit board 31 is parallel to the first circuit board 31; the transparent glass press head 86 and the laser device 861 are arranged on the surface of the flexible circuit board 35 which is away from the first circuit board 31, the laser 85 is emitted by the laser emitting device, the laser 85 passes through the glass press head 86 by the reflection of the prism 851 and the dispersion of the laser device 861 and irradiates the conductive paste 87 to melt the conductive paste 87, the conductive paste 87 rises along the surface in the first through hole 3553 under the extrusion of the glass press head 86 and overflows in the direction away from the first circuit board 31; the conductive paste 87 forms the conductive body 356 after solidification and connects the first pad 355 and the second pad 313, so as to realize the electrical connection between the first circuit board 31 and the flexible circuit board 35. In the embodiment, the second circuit board 32 and the flexible circuit board 35 are also welded by laser in the above structure and manner, and the specific steps of laser welding are not described here.

[0096] In some embodiments, in order 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, the point gluing process can be performed 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 FIG. 15, which is a schematic diagram of the connection between the first circuit board 31 and the flexible circuit board 35 according to some embodiments of the present application.

[0098] The first through hole 3553 is formed in 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; the second through hole 314 is formed in 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, the conductive paste 87 is arranged between the first circuit board 31 and the flexible circuit board 35, the first through hole 3553 and the second through hole 314 correspond; the conductive body 356 connecting the first circuit board 31 and the flexible circuit board 35 is formed by laser welding, the conductive body 356 is accommodated 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 conductive body 356 is approximately in the shape of a cross. The second circuit board 32 and the flexible circuit board 35 are also welded by using the above structure and mode, and the specific laser welding steps are not described here. In other embodiments, the reflow soldering mode can be used to realize the electrical connection between the first circuit board 31 and the flexible circuit board 35 without affecting other elements of the terminal device 100.

[0099] Please refer to Fig. 9 again, the terminal device 100 can also include a first battery 51, a second battery 52, a charging chip 61 and a system-level chip 62, the first battery 51 is located in the first folding area 11, the second battery 52 is located in the second folding area 12, the first battery 51 is electrically connected with the first circuit board 31, and the second battery 52 is electrically connected with the second circuit board 32. The first battery 51 is electrically connected with the first circuit board 31 through a first connecting plate 551, and the second battery 52 is electrically connected with 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 external charging. The Type C port 78 is electrically connected with the first circuit board 31 through a third connecting plate 553. In this embodiment, the first circuit board 31 is a main board, and the second circuit board 32 is a sub-board. The charging chip 61 and the system-level chip 62 are arranged on the first circuit board 31. The charging chip 61 is used for monitoring and controlling the current and voltage of the first battery 51 and the second battery 52 in the charging process in real time, so as to ensure the safety in the charging process.

[0100] The first connecting plate 551, the second connecting plate 552, and the third connecting plate 553 can each be a circuit board, and the electrical connection manner between the first connecting plate 551 and the first circuit board 31, the electrical connection manner between the second connecting plate 552 and the second circuit board 32, and the electrical connection manner between the third connecting plate 553 and the first circuit board 31 include but are not limited to a board-to-board connector (BTB), a film-on-board (FOB), and the like. In this embodiment, the first connecting plate 551 and the first circuit board 31, the second connecting plate 552 and the second circuit board 32, and the third connecting plate 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 the charger, the Type C port 78, the first connecting plate 551, the first circuit board 31, the charging chip 61, the protection plate of the first battery 51, the tab of the first battery 51, and the battery cell of the first battery 51. When charging the second battery 52, the current flow path includes the charger, the Type C port 78, the first connecting plate 551, the first circuit board 31, the charging chip 61, the laser welding point of the first circuit board 31 and the flexible circuit board 35, the flexible circuit board 35, the laser welding point of the flexible circuit board 35 and the second circuit board 32, the protection plate of the second battery 52, the tab of the second battery 52, and the battery cell of the second battery 52.

[0102] In this embodiment, the laser welding is used instead of at least one BTB electrical connection, which is conducive to reducing the thickness of the electrical connection area (i.e., the thickness of the terminal device 100 in the third direction L3), which is equivalent to increasing the distance from the electrical connection area to the outer surface (i.e., the shell) of the terminal device 100. That is, during the charging process, the distance between the user and the heat source can be increased, which is conducive to reducing the temperature felt by the user. In addition, the laser welding is used to directly connect the electrical connection, which is conducive to reducing the number of switching times, reducing the current flow path, and reducing the resistance, thereby reducing the heat generated during the charging process, and further reducing the temperature felt by the user. In this embodiment, compared with the related art of using BTB for electrical connection, the temperature reduction of the present embodiment is about 0.3-3°C.

[0103] In addition, the flexible circuit board 35 and the first circuit board 31 are electrically connected by FOB laser welding. The connection interfaces include the circuit layer and the first pad 355 of the flexible circuit board 35, the conductive body 356 and the first pad 355 and the second pad 313, and the circuit layer and the second pad 313 in the first circuit board 31, that is, a total of three connection interfaces. If the BTB connection mode is used, the connection interfaces include the surface of the circuit layer in the first circuit board 31, the welding point of the first circuit board 31 and the female pad 311', the female pad 311', the gap between the female pad 311' and the male pad 351', the male pad 351', the welding point of the male pad 351' and the flexible circuit board 35, and the surface of the circuit layer in the flexible circuit board 35, that is, a total of seven connection interfaces. The required connection interfaces of the BTB connection and the FOB connection are summarized in the following table. Therefore, compared with the BTB connection, the flexible circuit board 35 and the first circuit board 31 are connected by laser welding, and the transmission of the radio frequency signal can be realized in the welding area.

[0104] Referring to FIG. 16, FIG. 16 is a structural comparison diagram of connecting the first circuit board 31 and the flexible circuit board 35 by BTB and laser welding respectively. In FIG. 16, (a) represents the BTB connection of the first circuit board 31 and the flexible circuit board 35, (b) represents the laser welding connection of the first circuit board 31 and the flexible circuit board 35, and the dashed area in FIG. 16 and other figures represents the area 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-chip 62 on the first circuit board 31 along the third direction L3 and the flexible circuit board 35 in (b) 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-chip 62 on the first circuit board 31 along the third direction L3 and the flexible circuit board 35 can be 0.5mm-30mm. In addition, compared with the BTB electrical connection, the laser welding is beneficial to reduce the thickness of the terminal device 100 along the third direction L3.

[0106] The first circuit board 31' shown in FIG. 16 further connects a universal flash storage 63', a second connecting plate 551' and a third connecting plate 553'. The universal flash storage 63, the second connecting plate 551 and the third connecting plate 553 are arranged on the first circuit board 31. Taking the universal flash storage 63, the second connecting plate 551 and the third connecting plate 553 arranged on the first circuit board 31 as an example, the universal flash storage 63 is arranged apart from the system chip 62. The universal flash storage 63 is a main medium for storing operating systems and application programs in the mobile phone, and can provide a large storage space for the mobile phone, so that the user can install and run various application programs. The second connecting plate 551 is used for connecting the first battery 51. The third connecting plate 553 is used for connecting the Type C port 78.

[0107] Please refer to FIG. 17, FIG. 18A and FIG. 18B. FIG. 17 is a top view of the terminal device 100 according to an embodiment of the present application. FIG. 18A is a cross-sectional view of a partial area of the terminal device 100 according to some embodiments. FIG. 18B is a cross-sectional view of a partial area of the terminal device 100 shown in FIG. 17 along the direction of I-I.

[0108] Please refer to FIG. 18A. The terminal device 100 further includes support plates 74, fixing blocks 75, reinforcing plates 76 and appearance covers 73. The support plates 74 are two, and are respectively located in the first folding area 11 and the second folding area 12. The support plates 74 are respectively used for supporting the screens 71 in the corresponding areas. The fixing blocks 75 are located in the rotating shaft area. The flexible circuit board 35 passes through the first rotating shaft area 21 between the fixing blocks 75 and the appearance covers 73. The reinforcing plates 76 are arranged between the appearance covers 73 and the flexible circuit board 35, and are used for reinforcing the strength of the flexible circuit board 35.

[0109] In the embodiment, the electrical connection mode of the BTB is adopted. When assembling the screen 71, the support plate 74, the fixing block 75, the middle frame 72, the appearance cover 73 and the flexible circuit board 35 in the terminal device 100, the flexible circuit board 35 is usually assembled in the order of the screen 71, the support plate 74, the fixing block 75, the flexible circuit board 35, the reinforcing plate 76, the appearance cover 73 and the middle frame 72, or in the order of the middle frame 72, the appearance cover 73, the reinforcing plate 76, the flexible circuit board 35, the fixing block 75, the support plate 74 and the screen 71.

[0110] When the flexible circuit board 35 needs to be disassembled or replaced due to failure, since the screen 71, the support plate 74, the fixing block 75, the appearance cover 73 and other elements have been installed, and the elements in the terminal device 100 are densely arranged, the gap reserved for the flexible circuit board 35 is small, usually no more than 0.5 mm, and the thickness of the male solder pad 351' of the flexible circuit board 35 is difficult to pass through the narrow gap. Therefore, when the flexible circuit board 35 needs to be disassembled or replaced, the flexible circuit board 35 obtained after being disassembled in the reverse order of the above installation needs to be repaired or replaced, and then the disassembled elements are reassembled. The above steps are prone to damage to the elements, such as damage to the screen 71. In addition, in the actual terminal device 100, other elements such as a rotating shaft are also included, and the difficulty of the assembly and disassembly steps is large.

[0111] Please refer to FIG. 18B. The difference between FIG. 18B and FIG. 18A is that the electrical connection between the first circuit board 31 and the flexible circuit board 35 in FIG. 18B is achieved through laser welding, and the surface of the flexible circuit board 35 is not provided with a male solder pad 351' with a relatively large thickness. The overall thickness of the flexible circuit board 35 is relatively small, and the flexible circuit board 35 can be disassembled and assembled without disassembling other elements in the terminal device 100.

[0112] Please refer to FIG. 18C, which is a cross-sectional schematic diagram of a partial area of a terminal device 100 provided by some embodiments of the present application. In the present embodiment, the dashed circle in the figure represents that the flexible circuit board 35 can be folded around a virtual inner diameter.

[0113] Please refer to FIG. 19 and FIG. 20. FIG. 19 is a cross-sectional flowchart of the process of bonding the first traction piece 81 to the flexible circuit board 35, and FIG. 20 is a top view flowchart of the process of bonding the first traction piece 81 and the second traction piece 82 to the flexible circuit board 35.

[0114] Specifically, both ends of the flexible circuit board 35 along the first direction L1 are provided with bonding areas 357. When the flexible circuit board 35 needs to be disassembled, the conductive body 356 can be melted by laser irradiation to separate the flexible circuit board 35 from the first circuit board 31 and the second circuit board 32. The first traction piece 81 and the second traction piece 82 are both coated with an adhesive layer 83. The first traction piece 81 is bonded to the bonding 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 bonding area 357 of the flexible circuit board 35 located in the second folding area 12. In the present 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 sheet 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 sheet 81 and the second traction sheet 82 along the first direction L1 is 0.02mm-50mm, the width E of the adhesive area 357 along the first direction L1 is Dx90% 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 meanings of each letter and the summary of the sizes are shown in the following table.

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

[0117] Please refer to FIG. 21 and FIG. 22, FIG. 21 is a cross-sectional flowchart of the embodiment of the present application using the first traction sheet 81 and the second traction sheet 82 to disassemble the flexible circuit board 35 from the terminal device 100, and FIG. 22 is a cross-sectional flowchart of the embodiment of the present application using the first traction sheet 81 and the second traction sheet 82 to assemble the flexible circuit board 35 in the terminal device 100.

[0118] Please refer to FIG. 21, the force F1 can be applied to the second traction sheet 82 to pull the second traction sheet 82 from the second folding area 12, and drive the flexible circuit board 35 to exit from the first folding area 11, the first pivot area 21 in turn, so that the first traction sheet 81 adhered to the flexible circuit board 35 passes through the first pivot area 21, and the two ends of the first traction sheet 81 are located in the first folding area 11 and the second folding area 12 respectively, that is, the first traction sheet 81 is temporarily located in the terminal device 100.

[0119] Please refer to FIG. 22, when the flexible circuit board 35 needs to be re-installed after maintenance or replacement, the first traction piece 81 is re-adhered to the adhering area 357 of the flexible circuit board 35, the first traction piece 81 is pulled out from the first folding area 11, and the first traction piece 81 is sequentially pulled out from the second folding area 12, the first rotation shaft area 21 and the first folding area 11, while driving the flexible circuit board 35 to pass through the first rotation shaft area 21, and the two ends of the flexible circuit board 35 are located in the first folding area 11 and the second folding area 12 respectively, and the two ends of the flexible circuit board 35 are electrically connected to the first circuit board 31 and the second circuit board 32 respectively. The flexible circuit board 35 is installed by using the first traction piece 81 and the second traction piece 82 to assist in dismounting and installing the flexible circuit board 35, which can reduce the number of components to be dismounted and reduce the risk of damaging the components compared with the related art.

[0120] It can be understood that in the step of initially assembling the terminal device 100, other components can also be assembled and the first traction piece 81 can be pre-buried, and when the flexible circuit board 35 needs to be installed, the first traction piece 81 is adhered to the flexible circuit board 35 and then installed.

[0121] Please refer to FIG. 23 and FIG. 24, FIG. 23 is a cross-sectional view of the flexible circuit board 35 provided by some embodiments of the present application, and FIG. 24 is a cross-sectional view of the flexible circuit board 35 provided by some other embodiments of the present application.

[0122] The number of layers of the circuit layer 45 in the flexible circuit board 35 is multiple, for example, two layers, three layers or four layers, etc., and the flexible circuit board 35 further comprises an electromagnetic shielding layer 41, the electromagnetic shielding layer 41 is located on the surface of the cover layer 46 of the flexible circuit board 35, and the electromagnetic shielding layer 41 is the outermost layer of the flexible circuit board 35, and the adhering area 357 and the area where the second solder pad 313 is located of the flexible circuit board 35 are not provided with the electromagnetic shielding layer 41.

[0123] In the embodiment shown in FIG. 24, the flexible circuit board 35 is provided with the electromagnetic shielding layer 41 on both surfaces, and includes three layers of circuit layers 45. The flexible circuit board 35, from top to bottom and corresponding thickness, is in turn the electromagnetic shielding layer 41 (10.0 μm), the dielectric layer 42 (12.3 μm), the adhesive layer 44 (17.0 μm), the circuit layer 45 (22.0 μm), the dielectric layer 42 (12.5 μm), the base film layer 43 (25.0 μm), the dielectric layer 42 (12.5 μm), the adhesive layer 44 (17.0 μm), the circuit layer 45 (22.0 μm), the dielectric layer 42 (12.5 μm), the base film layer 43 (25.0 μm), the dielectric layer 42 (12.5 μm), the circuit layer 45 (22.0 μm), the adhesive layer 44 (17.0 μm), the dielectric layer 42 (12.3 μm), and the electromagnetic shielding layer 41 (10.0 μm). Each of the circuit layers 45 is formed by a copper foil (7.0 μm) and a plated copper layer (15.0 μm) formed on the copper foil, and in some manufacturing steps, the copper foil is subjected to a copper reduction treatment, 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 as needed, and the adjustment range is 20%-300% of the overall thickness or the thickness of each layer. The dimensions of each layer are summarized in the following table.

[0124] Referring to FIGS. 25A and 25B, both of which are top views of the flexible circuit board 35 according to some embodiments of the present application. In the embodiments shown in FIGS. 25A and 25B, along the first direction L1, the flexible circuit board 35 is provided with a plurality of rows of cavities 47, which facilitate bending of the flexible circuit board 35 in the region where the cavities 47 are provided. The flexible circuit board 35 is provided with three rows of cavities 47, two rows of cavities 47 on the sides are used to correspond to the end portions of the appearance cover 73, and one row of cavities 47 in the middle is used to correspond to the middle region of the appearance 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 the adhesive layer 44 in the corresponding region. In FIG. 25A, the region of the flexible circuit board 35 used for welding is provided with the first solder pad 355, which can be used for laser welding, and in FIG. 25B, the region of the flexible circuit board 35 used for welding can be connected by BTB.

[0125] Referring to FIG. 26, which is a schematic cross-sectional view of the flexible circuit board 35 according to some embodiments of the present application. When the number of circuit layers 45 in the flexible circuit board 35 is two, one side of the flexible circuit board 35 is provided with a ground layer, which is used to provide a reference potential in the circuit design and helps to 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, both sides of the flexible circuit board 35 are provided with ground layers, and the electromagnetic shielding layer 41 can also be provided.

[0126] In the present embodiment, the number of circuit layers 45 in the flexible circuit board 35 is two. In order to reduce signal interference and noise, the signal line 452-1 is wrapped with a ground line 451 (GND), which can ensure more stable signal transmission. Each circuit layer 45 includes a signal line and a ground line 451, and the two signal lines are signal line 452-1 and signal line 452-2. The wiring width J of the signal line 452-1 or the signal line 452-2 is 0.02mm-2mm, the interval distance K between the two signal lines and the ground line 451 is 0.5J-2J, and the wiring width L of the ground line 451 is 1J-5J. The orthographic projection of one layer of signal line 452-1 on 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 details are shown in the following table.

[0127] Referring to FIG. 27A, FIG. 27A is a structural schematic diagram of the first pads 355 of the flexible circuit board 35 according to an embodiment of the present application. The first via holes 3553 on the flexible circuit board 35 can be elliptical, and the first pads 355 of the flexible circuit board 35 are rectangular in the top view in one orientation. The aperture a of the first via holes 3553 in the short direction is 0.045-0.45 mm, the width b of the first pads 355 in the short direction is 0.105-1.05 mm, the aperture c of the first via holes 3553 in the long direction is 0.045-0.45 mm, and the width d of the first pads 355 in the long direction is 0.105-1.05 mm. The number of the first pads 355 is at least two rows, at least one row of which is used for grounding and at least one row of which is used for signal transmission. The distance e between the first pads 355 for grounding and the first pads 355 for signal transmission is 0.075-0.75 mm, the width g of the signal line connected to the first pads 355 is 0.0315-0.35 mm, the impedance of the control signal line is within 50 Ω, the distance m between the two adjacent first pads 355 for signal transmission is 0.075-0.75 mm, the distance n between the two adjacent first pads 355 is 0.18-1.8 mm, and the two adjacent first pads 355 include the two first pads 355 in the left-right direction or the up-down direction. The summary of the above-mentioned various dimensions is as follows.

[0128] Referring to FIG. 27B, FIG. 27B is a structural schematic diagram of the first pads 355 of the flexible circuit board 35 according to another embodiment of the present application. In this embodiment, the first pads 355 on the outer side of the flexible circuit board 35 can be designed as dumbbell-shaped, and the dumbbell-shaped first pads 355 have large sizes at both ends and small size in the middle, which is beneficial to improve the 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 ports (GPIO), sensors, audio signals, antennas, baseband power supplies, control signals, etc., and other signals are ground signals.

[0130] The radio frequency signal is usually very sensitive to interference, and the complete and independent package ground 451 design around the radio frequency signal can ensure the stability and purity of the radio frequency signal. Similar to the radio frequency signal, the screen signal, sensor, etc. also need a stable transmission environment, and the package ground 451 design is also designed around them. The distance between the pad of the antenna and the pad of the power signal is at least 3mm to ensure that the antenna signal will not be disturbed by the power signal. The position of the user's handheld terminal device 100 is different, which will also have a certain influence on the antenna signal. The distance between the ground 451 of the antenna and the ground 451 of other signals is at least 2mm, and the distance between the trace of the ground 451 of the antenna and the trace of the ground 451 of other signals is at least 3mm to prevent interference between the grounds 451. When the ground 451 of the antenna is close to the signal line of other signals, in order to ensure the stability of the signal, the width of the ground 451 should be at least 0.1mm.

[0131] The following lists different types of signals and connections, as well as their final connection objects. Among them, the power signal is a signal that provides electrical energy, usually 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 is a power supply that provides electrical energy for the baseband chip dedicated to the terminal device 100, and the baseband chip is a key component in communication equipment such as mobile phones for processing communication signals (such as voice, data, etc.). The radio frequency signal is a signal used in wireless communication, such as mobile phone communication, WiFi, etc., and the radio frequency antenna switch is a switch that controls the transmission or reception of radio frequency signals from which antenna. The audio signal is an electronic representation of sound information, and the audio signal is sent to the speaker 77 (BOX) for processing or playing. The charging VBUS refers to the charging bus or charging power line, and the charging chip 61 is responsible for controlling and managing the charging process to ensure that the battery is safely and effectively charged. The GPIO is an interface of the terminal device 100 for system interaction with other hardware, and the GPIO communicates with the chip on the second circuit board 32, which can be used for data transmission, control or other interactive functions. The test pin is a pin for testing or debugging, and the BTB test refers to the board-to-board test, which is a test to verify the reliability of the connection between two or more circuit boards. The sensor is an element for detecting and measuring physical quantities (such as temperature, pressure, acceleration, etc.), and the semiconductor sensor includes an accelerometer, a gyroscope, and a barometer, etc., which are used to measure acceleration, angular velocity, and atmospheric pressure, respectively. The screen signal is a signal used to communicate with the screen 71, which can include image data, control signals, etc., and these signals ensure that the screen 71 can correctly display the content and effectively communicate with the first circuit board 31. The summary of the above different types of signals and connections, as well as their final connection objects, is as follows.

[0132] Referring to FIG. 28, FIG. 28 is a connection diagram of the circuit layer 45 according to an embodiment of the present application. In some embodiments, the power supply signal, the GPIO, the charger interface, the GND, the screen signal, the RF signal, another power supply signal, and the same circuit layer 45 are connected, which is mainly responsible for the power supply of the device, communication with external devices, and charging functions. The power supply is the basis for the operation of the device, the GPIO allows the terminal device 100 to exchange data with other electronic elements or devices, the charger interface is used to connect the external power supply for charging, and the ground connection is the key to ensure the safety and stability of the circuit. The power supply signal, the GND, and another power supply signal are connected to another circuit layer 45. The power supply signal, the organic light-emitting diode, the test interface, the GPIO, the RF signal, another power supply signal, and another circuit layer 45 are connected, and the organic light-emitting diode is used as a display element. Each circuit layer 45 carries different electronic elements 64 and connections, which together constitute the electrical system of the terminal device 100 to be responsible for power supply, communication, charging, wireless communication, display, testing, and debugging functions.

[0133] Referring to FIG. 29, FIG. 29 is a diagram of the internal element distribution of the terminal device 100a according to another embodiment of the present application. The difference from the embodiment shown in FIG. 8 is that in the embodiment shown in FIG. 29, the terminal device 100a 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 turn, and the plurality of 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; the flexible circuit board 35a penetrates through the first hinge area 21, the second folding area 12, and the second hinge 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 by laser welding, and / or the flexible circuit board 35a is electrically connected to the second circuit board 32 by laser welding, and / or the flexible circuit board 35a is electrically connected to the third circuit board 33 by laser welding.

[0134] In this embodiment, the flexible circuit board 35a is approximately T-shaped, and the flexible circuit board 35a is electrically connected by the laser welding connection mode of the flexible circuit board 35a and the second circuit board 32. The flexible circuit board 35a can penetrate through multiple hinge areas, which is conducive to improving the quality of the radio frequency signal; and is conducive to reducing the number of BTBs, and thus is conducive to improving the layout area of the flexible circuit board 35a.

[0135] The terminal device 100a comprises 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 is electrically connected with the first circuit board 31, the second battery 52 is located in the second folding area 12 and is electrically connected with the second circuit board 32, and the third battery 53 is located in the third folding area 13 and is electrically connected with the third circuit board 33 through the fourth connecting plate 554. The terminal device 100a further comprises a Type C port 78 and a loudspeaker 77, the Type C port 78 is located in the first folding area 11 and is electrically connected with the first circuit board 31, and the loudspeaker 77 is located in the third folding area 13 and is electrically connected with the third circuit board 33. A recess 721 is formed in the middle frame 72 located in the second folding area 12, and the flexible circuit board 35a located in the second folding area 12 can be embedded in the recess 721 to reduce the thickness of the 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 plate 551, first circuit board 31, charging chip 61, protection plate of first battery 51, tab of first battery 51 and core of first battery 51; when charging the second battery 52, the current flow path includes: charger, Type C port 78, first connecting plate 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 plate of second battery 52, tab of second battery 52 and core of second battery 52; when charging the third battery 53, the current flow path includes: charger, Type C port 78, first connecting plate 551, 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 third circuit board 33, third circuit board 33, protection plate of third battery 53, tab of third battery 53 and core of 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, but can be directly transmitted to the third circuit board 33 through the flexible circuit board 35a.

[0137] In the embodiment, the flexible circuit board 35a is electrically connected to the first circuit board 31 with the charging chip 61 by laser welding, which is conducive to reducing the thickness of the welding position, increasing the distance between the user and the heat source during the charging process, and reducing the temperature felt by the user. In addition, laser welding is used to directly electrically connect, which is conducive to reducing the number of switching times, reducing the current flow path, and reducing the resistance, thereby reducing the heat generated during the charging process, and further reducing the temperature felt by the user. One flexible circuit board 35a can be electrically connected to the first circuit board 31, the second circuit board 32 and the third circuit board 33 at the same time, so as to improve the quality of the radio frequency signal. Laser welding can reduce the number of BTBs and improve the layout area of the circuit. At the same time, the above-mentioned method of assisting the first traction piece 81 and the second traction piece 82 can also be used to realize the disassembly and installation of the flexible circuit board 35a.

[0138] The first circuit board 31 is also connected to elements such as PAMiD 621 (Power Amplifier Module integrated with Duplexer) and radio frequency switch 622 (SW). The main function of PAMiD 621 is to amplify, filter and switch control the signal when the terminal device 100a transmits the signal, so as to ensure that the signal can be efficiently transmitted to the antenna and sent out. The radio frequency switch 622 is used to switch the signal path between multiple frequency bands, so as to ensure that the terminal device 100a can receive and send signals from different networks.

[0139] Please refer to FIG. 30A and FIG. 30B, which are respectively schematic diagrams of internal element distribution of the terminal device 100b provided by some other embodiments of the present application.

[0140] The difference between the embodiment shown in FIG. 29 and the embodiment shown in FIG. 30A is that the flexible circuit board 35b is approximately T-shaped in the embodiment shown in FIG. 30A, and the flexible circuit board 35b and the second circuit board 32 can be electrically connected by the connection mode of BTB (as shown in FIG. 30A) or FOB (as shown in FIG. 30B). In other embodiments, the electrical connection mode of the flexible circuit board 35b and the second circuit board 32 is not limited to the above two modes, and can also be connected by connecting other circuit boards for switching, etc.

[0141] The flexible circuit board 35b passes through the second folding area 12, and the step of installing the flexible circuit board 35b can be implemented after the second battery 52 is installed. The flexible circuit board 35b can be arranged 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 arranged in the middle frame 72 to reduce the overall thickness of the terminal device 100b, the embodiment does not arrange the groove 721 on the middle frame 72, which is conducive to improving the strength of the middle frame 72.

[0142] In the embodiment, the terminal device 100b includes two charging chips 61, which are respectively arranged on the first circuit board 31 and the second circuit board 32. The charging chip 61 arranged 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. The charging chip 61 arranged 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 of the embodiment shown in FIG. 29, except that the current flow path when charging the second battery 52. When charging the second battery 52, the current flow path includes: the charger, the Type C port 78, the first connecting plate 551, the laser welding point of the first circuit board 31 and the flexible circuit board 35b, the flexible circuit board 35b, the laser welding point of the flexible circuit board 35b and the second circuit board 32, the charging chip 61 on the second circuit board 32, the protection plate of the second battery 52, the tab of the second battery 52, and the battery cell of the second battery 52.

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

[0145] Referring to FIG. 31, FIG. 31 is a schematic diagram of internal elements distribution of a terminal device 100c according to some embodiments of the present application. In the embodiment shown in FIG. 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, and a plurality of circuit boards including 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; a flexible circuit board 35c penetrates through the first hinge area 21, the second folding area 12, the second hinge area 22, the third folding area 13, and the third hinge area 23 and electrically connects the first circuit board 31, the second circuit board 32, the third circuit board 33, and the fourth circuit board 34; the flexible circuit board 35c is electrically connected to the first circuit board 31 after laser welding, and / or the flexible circuit board 35c is electrically connected to the second circuit board 32 after laser welding, and / or the flexible circuit board 35c is electrically connected to the third circuit board 33 after laser welding, and / or the flexible circuit board 35c is electrically connected to the fourth circuit board 34 after laser welding. The fourth folding area 14 is also provided with a fourth battery 54 corresponding thereto, and the fourth battery 54 is connected to the fourth circuit board 34 through a sixth connecting plate 556.

[0146] Please refer to FIGS. 32-39, which are respectively schematic diagrams of internal elements of the terminal device 100d according to some other embodiments of the present application. In the embodiments shown in FIGS. 9, 29-31, the flexible circuit board 35 is used to electrically connect the circuit boards in different folding areas. The main difference between the embodiments shown in FIGS. 9, 29-31 and the embodiments shown in FIGS. 32-39 is that, in the embodiments shown in FIGS. 32-39, the rigid-flex board is used to electrically connect the circuit boards in different folding areas. The terminal device 100d is divided into at least two folding areas and a hinge area between the adjacent two folding areas. The terminal device 100d includes a plurality of circuit boards, a charging chip 61 and a conductive body 356. At least one circuit board is arranged in each folding area. At least one circuit board in the plurality of circuit boards is a rigid-flex board. The rigid-flex board includes a hard board portion 36d and a soft board portion 37d. The hard board portion 36d is located in the folding area, and the soft board portion 37d penetrates through the hinge area. The conductive body 356 connects the soft board portion 37d and the circuit board other than the rigid-flex board. The conductive body 356 is formed by laser welding. The charging chip 61 is arranged on at least one circuit board and electrically connected with the circuit board. The rigid-flex board is a one-piece structure, and no additional electrical connection method (such as laser welding, reflow soldering, BTB connection, etc.) is needed to achieve electrical connection, which is equivalent to further reducing the number of relays and further reducing the heat generated during charging. The terminal device 100d further includes a system-level chip 62. When the charging chip 61 is one, the system-level chip 62 and the charging chip 61 are arranged on the same circuit board. When the charging chip 61 is a plurality, the system-level chip 62 and at least one charging chip 61 are arranged on the same circuit board.

[0147] It can be understood that the technical features suitable for the embodiments shown in FIGS. 9, 29-31 can also be adaptively applied to the embodiments shown in FIGS. 32-39 on the premise that the functions of the embodiments shown in FIGS. 32-39 can be achieved.

[0148] Please refer to FIG. 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. The plurality of circuit boards includes a first circuit board 31d and a second circuit board 32d. The first circuit board 31d is a rigid-flex board. The hard board portion 36d is located in the first folding area 11. The soft board portion 37d penetrates through the first hinge area 21 and extends to the second folding area 12. The first circuit board 31d is approximately L-shaped. The charging chip 61 is arranged on the hard board portion 36d and electrically connected with the hard board portion 36d. The second circuit board 32d is located in the second folding area 12. The soft board portion 37d is electrically connected with the second circuit board 32d through the conductive body 356 formed by laser welding.

[0149] In the embodiment, the first circuit board 31d is a rigid-flexible combined board, and no additional electrical connection mode is needed to realize electrical connection. Compared with the embodiment in which the electrical connection is realized by the conductive body 356, the embodiment can further reduce the thickness of the electrical connection area and further reduce the resistance, thereby reducing the heat generated in the charging process.

[0150] The number of layers of the circuit layer in the rigid-flexible combined board located in the rigid board portion 36d is usually multiple, for example, greater than or equal to three.

[0151] In some embodiments, the end of the soft board portion 37d away from the rigid board portion 36d is provided with an adhesive area 357, which is used to cooperate with the first traction piece 81, thereby playing an adhesive role in the disassembly or assembly steps of the rigid-flexible combined board, replacing the need to disassemble and assemble too many elements in the related art, and reducing the risk of element damage. In some embodiments, the rigid-flexible combined board includes a cavity 47 located in the soft board portion 37d, and the rigid-flexible combined board is bent in the area of the cavity 47.

[0152] Please refer to FIG. 33. The difference between the embodiment shown in FIG. 33 and the embodiment shown in FIG. 32 is that in the terminal device 100e shown in FIG. 33, the first circuit board 31e is located in the first folding area 11; the second circuit board 32e is a rigid-flexible combined board, and the rigid board portion 36e is located in the second folding area 12. The charging chip 61 is arranged on the first circuit board 31e and electrically connected with the first circuit board 31e, the soft board portion 37e penetrates through the first rotating shaft area 21 and extends to the first folding area 11, and the soft board portion 37e is electrically connected with the first circuit board 31e through the conductive body 356 formed by laser welding.

[0153] Please refer to FIG. 34. The difference between the embodiment shown in FIG. 34 and the embodiment shown in FIG. 33 is that the terminal device 100f shown in FIG. 34 includes a first circuit board 31f, a second circuit board 32f and a third circuit board 33f. The second circuit board 32f and the third circuit board 33f are both located in the second folding area 12, and both the second circuit board 32f and the third circuit board 33f are rigid-flexible combined boards. The rigid board portions 36f of the second circuit board 32f and the third circuit board 33f are both located in the second folding area 12, and the soft board portions 37f of the second circuit board 32f and the third circuit board 33f both penetrate through the first rotating shaft area 21 and extend to the first folding area 11, and are electrically connected with the first circuit board 31f through laser welding.

[0154] Please refer to FIG. 35. The terminal device 100g is divided into a first folding area 11, a first rotating shaft area 21, a second folding area 12, a second rotating shaft area 22 and a third folding area 13 connected in sequence. The plurality of 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-flexible combined board, the rigid board part 36g is located in the first folding area 11, and the charging chip 61 is arranged on the rigid board part 36g and electrically connected with the rigid board part 36g; the flexible board part 37g penetrates through the first rotating shaft area 21, the second folding area 12 and the second rotating shaft area 22 and extends to the third folding area 13. The flexible board part 37g can pass through multiple rotating shaft areas, which is beneficial to improving the radio frequency signal quality; and is beneficial to reducing the number of BTBs, thereby being beneficial to improving the layout area of the rigid-flexible combined 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] Please refer to FIG. 36, the terminal device 100h is divided into the first folding area 11, the first rotating shaft area 21, the second folding area 12, the second rotating shaft area 22 and the third folding area 13 connected in sequence, and multiple circuit boards include the first circuit board 31h, the second circuit board 32h and the third circuit board 33h. The first circuit board 31h is located in the first folding area 11, the third circuit board 33h is located in the third folding area 13, and the charging chip 61 is arranged on the first circuit board 31h and electrically connected with the first circuit board 31h. The second circuit board 32h is a rigid-flexible combined board, the rigid board part 36h is located in the second folding area 12, the flexible board part 37h penetrates through the first rotating shaft area 21 and extends to the first folding area 11 and is electrically connected with the first circuit board 31h, and the flexible board part 37h also penetrates through the second rotating shaft area 22 and extends to the third folding area 13 and is electrically connected with the third circuit board 33h. The flexible board part 37h and the first circuit board 31h are electrically connected through the conductive body 356 formed after laser welding, and the flexible board part 37h and the third circuit board 33h are electrically connected through the conductive body 356 formed after laser welding.

[0158] Please refer to FIG. 37, the terminal device 100i is divided into the first folding area 11, the first rotating shaft area 21, the second folding area 12, the second rotating shaft area 22 and the third folding area 13 connected in sequence, and multiple circuit boards include the first circuit board 31i, the second circuit board 32i and the third circuit board 33i. The first circuit board 31i is located in the first folding area 11, the charging chip 61 is arranged on the first circuit board 31i and electrically connected with 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-flexible combined board, the third circuit board 33i is approximately Z-shaped, the rigid board part 36i is located in the third folding area 13, and the flexible board part 37i penetrates through the second rotating shaft area 22, the second folding area 12, the first rotating shaft area 21 and extends to the first folding area 11. The flexible board part 37i and the first circuit board 31i are electrically connected through the conductive body 356 formed after laser welding, and the flexible board part 37i and the second circuit board 32i are electrically connected through the conductive body 356 formed after laser welding.

[0159] Referring to FIG. 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, and a plurality of circuit boards including a first circuit board 31j, a second circuit board 32j and a third circuit board 33j. The first circuit board 31j and the third circuit board 33j are both rigid-flex boards, the first circuit board 31j is substantially L-shaped, and the third circuit board 33j is substantially Z-shaped. The charging chip 61 is disposed on the rigid portion 36j of the first circuit board 31j and electrically connected with the rigid portion 36j, and 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 with the second circuit board 32j, and 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 with the flexible portion 37j of the first circuit board 31j. The flexible portion 37j of the first circuit board 31j and the second circuit board 32j are electrically connected through a conductive body 356 formed by laser welding, and the flexible portion 37j of the third circuit board 33j and the flexible portion 37j of the first circuit board 31j are electrically connected through a conductive body 356 formed by laser welding.

[0160] Referring to FIG. 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, and a plurality of circuit boards including 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 the first circuit board 31k and electrically connected with the first circuit board 31k. The second circuit board 32k and the third circuit board 33k are both rigid-flex boards, and the second circuit board 32k and the third circuit board 33k are both substantially 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 extends through the first hinge area 21 to the first folding area 11 and is electrically connected with the first circuit board 31k, and the flexible portion 37k of the third circuit board 33k extends through the second hinge area 22 to the second folding area 12 and is electrically connected with 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 through a conductive body 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 through a conductive body 356 formed by laser welding.

[0161] Referring to FIG. 40 and FIG. 41, FIG. 40 is a cross-sectional view of a rigid-flex board according to some embodiments of the present application; and FIG. 41 is a flowchart of manufacturing the rigid-flex board shown in FIG. 40.

[0162] In the embodiment, the rigid-flex printed circuit board includes two rigid board portions 361 and one soft board portion 371, the soft board portion 371 is located between the two rigid board portions 361, the number of layers of the circuit layer of the soft board portion 371 is two, and the number of layers of the circuit layer of the rigid board portion 361 is eight. The design parameters of the rigid-flex printed circuit board can be referred to the following table.

[0163] The rigid-flex printed circuit board of the embodiment can be manufactured by using the flow chart shown in FIG. 41, which can generally include cutting processing on specific areas or specific layers of incoming materials, forming positioning holes in predetermined areas for accurate positioning in subsequent processes, replacing tools or adjusting process parameters as needed during the processing of rigid materials such as FR4; pre-processing the incoming materials of polypropylene (PP); forming positioning holes in predetermined areas of the incoming materials of the flexible circuit board and making circuits to obtain the expected circuit pattern, pasting the cover film with pre-drilled positioning holes on the semi-finished product of the circuit pattern and pressing, and forming through holes after pressing the polypropylene and the rigid material together; increasing the thickness of the copper layer by copper plating and plate plating to obtain a circuit pattern with appropriate thickness, etching the circuit pattern of the specific area to obtain a circuit layer, forming a solder mask layer (i.e., green oil) on the surface of the circuit layer and then performing surface treatment, uncovering treatment, and profile treatment to expose the area for forming electrical connection in the subsequent process, obtaining the flexible circuit board, and performing electrical performance test and other performance test on the flexible circuit board, packaging after the test is qualified, and obtaining the final product.

[0164] The above embodiments are only used to illustrate the technical solutions of the present application rather than limit the present application. Although the present application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present 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 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 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 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, and 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, which plays an adhesive role 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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