Circuit board assembly and electronic device

Abstract

The embodiments of the present application relate to the technical field of display. Provided are a circuit board assembly and an electronic device, which are used for alleviating the problem of electronic devices undergoing severe overheating and causing limitations on product performance. In the circuit board assembly, a SoC circuit is arranged on a first circuit board, a second circuit board and the first circuit board are spaced apart, and a radio frequency circuit is arranged on the second circuit board. One end of an electrical connection member is electrically connected to the first circuit board, and the other end of the electrical connection member is electrically connected to the second circuit board; and the SoC circuit is electrically connected to the radio frequency circuit by means of the electrical connection member. By respectively arranging components that serve as main heating sources, such as the SoC circuit and the radio frequency circuit, on the first circuit board and the second circuit board that are independent of each other and spaced apart, heating sources being concentrated on the same circuit board can be avoided, thereby reducing the probability of excessive local heat and severe overheating of the circuit board assembly.

Description

Circuit board assembly and electronic equipment

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on January 15, 2024, with application number 202410059906.4 and invention name “A circuit board assembly, electronic device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of display technology, and in particular to a circuit board assembly and an electronic device. Background Art

[0003] With technological advancements, electronic devices are developing towards multifunctionality and high speed. The increasing integration of electronic components, such as system chips, central processing units (CPUs), graphics processing units (GPUs), and memory, has led to a significant increase in power consumption and, in turn, heat generation. Electronic devices are also required to meet the requirements of lightweight and thin design. This has led to continued thinning of the body, limiting heat dissipation. At the same time, overall device performance continues to improve, resulting in significant heat generation in electronic devices, impacting product performance.

[0004] Summary of the Invention

[0005] The present application provides a circuit board assembly and an electronic device for alleviating the problem of severe heating of electronic devices, which leads to limited product performance.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] In one aspect of the present application, a circuit board assembly is provided, which includes a first circuit board, a SoC circuit, a second circuit board, a radio frequency circuit and an electrical connector. The SoC circuit is arranged on the first circuit board, and the SoC circuit is electrically connected to the first circuit board. The second circuit board is spaced apart from the first circuit board. The radio frequency circuit is arranged on the second circuit board, and the radio frequency circuit is electrically connected to the second circuit board. One end of the electrical connector is electrically connected to the first circuit board, and the other end of the electrical connector is electrically connected to the second circuit board, and the SoC circuit is electrically connected to the radio frequency circuit via the electrical connector. As can be seen from the above, the embodiment of the present application can avoid the heat source from being concentrated on the same circuit board by arranging the components that serve as the main heat sources of the circuit board assembly, such as the SoC circuit and the radio frequency circuit, on the first circuit board and the second circuit board that are independent of each other and spaced apart, thereby reducing the probability of excessive local heat and severe heat in the circuit board assembly and improving the performance of the circuit board assembly.

[0008] In an optional embodiment, the RF circuit includes a RF chip and a RF antenna electrically connected to the RF chip. The SoC circuit includes a SoC chip and a clock chip electrically connected to the SoC chip. The SoC chip and the clock chip are electrically connected to the RF chip via an electrical connector. The circuit board assembly also includes a first low-pass filter circuit. The first low-pass filter circuit is electrically connected between the clock chip and the electrical connector, and the cutoff frequency of the first low-pass filter circuit is the starting frequency f11 of the operating frequency band of the RF antenna. In this way, the first low-pass filter circuit can filter out signals with a frequency that is the starting frequency f11 of the operating frequency band of the RF antenna and frequencies above the starting frequency f11 (i.e., ≥f11), thereby reducing the noise from the RF antenna from passing through the electrical connector and interfering with the RF reference clock on the part of the transmission link close to the clock chip.

[0009] In an optional embodiment, the circuit board assembly further includes a first connector disposed on the first circuit board, and the first connector is electrically connected between the first low-pass filter circuit and the electrical connector. Alternatively, if the electrical connector is a flexible circuit board, the electrical connector can be directly electrically connected to the first circuit board.

[0010] In an optional embodiment, the RF circuit includes a RF chip and a RF antenna electrically connected to the RF chip, and the RF chip is electrically connected to the SoC circuit through an electrical connector. The circuit board assembly also includes a second low-pass filter circuit, and the second low-pass filter circuit is electrically connected between the RF chip and the electrical connector. The cutoff frequency of the second low-pass filter circuit is the starting frequency f11 of the operating frequency band of the RF antenna. In this way, the frequency of the signal that can be filtered out by the second low-pass filter circuit is the starting frequency f11 of the operating frequency band of the RF antenna and the frequency above the starting frequency f11 (i.e., ≥f11), thereby reducing the interference of the noise from the RF antenna through the electrical connector on the RF reference clock on the part of the transmission link close to the RFIC chip, and reducing the impact of the above-mentioned noise on the performance of the RFIC chip after entering the RFIC chip.

[0011] In an optional embodiment, the circuit board assembly further includes a wireless charging coil and a high-pass filter circuit. The high-pass filter circuit is electrically connected between the RF chip and the electrical connector. The cutoff frequency of the high-pass filter circuit is the end frequency f22 of the operating frequency band of the wireless charging coil. The high-pass filter circuit is connected in series with the second low-pass filter circuit to form a bandpass filter circuit, and the bandpass frequency band of the bandpass filter circuit is f22 to f11. In this way, the high-pass filter circuit can filter out signals with frequencies that are the end frequency f22 of the operating frequency band of the wireless charging coil and frequencies below the end frequency f22 (i.e., ≤ f22), thereby reducing the interference of noise from the wireless charging coil through the electrical connector on the RF reference clock on the portion of the transmission link close to the RFIC chip, and reducing the impact of the noise on the performance of the RFIC chip after entering the RFIC chip. In addition, the above-mentioned bandpass filter circuit can simultaneously improve the isolation between the RF antenna and the RFIC chip, as well as the isolation between the wireless charging coil and the RFIC chip.

[0012] In an optional embodiment, the circuit board assembly further includes a second connector disposed on the second circuit board, and the second connector is electrically connected between the second low-pass filter circuit and the electrical connector. Alternatively, if the electrical connector is a flexible circuit board, the electrical connector can be directly electrically connected to the second circuit board.

[0013] Another aspect of the present application provides an electronic device comprising a display screen and any one of the circuit board assemblies described above, the circuit board assembly being electrically connected to the display screen. The electronic device has the same technical effects as the circuit board assembly provided in the aforementioned embodiment, and will not be described in detail here.

[0014] In an optional embodiment, the electronic device further includes: a first middle frame, a second middle frame, and a hinge assembly. The first middle frame is disposed on the back of the display screen, with the first circuit board disposed on the first middle frame. The second middle frame is disposed on the back of the display screen, with the second circuit board disposed on the second middle frame. The hinge assembly is disposed on the back of the display screen, between the first and second middle frames, and is connected to the first and second middle frames, such that the first middle frame is rotatably connected to the second middle frame via the hinge assembly. An electrical connector is disposed on the sides of the first and second middle frames facing away from the display screen, with a portion of the electrical connector passing through the hinge assembly. For example, the electrical connector may be a flexible printed circuit board (FPCB) or a coaxial cable. If the electrical connector passing through the hinge assembly is a FPCB, the electrical connector may be referred to as a through-axis FPCB. Alternatively, if the electrical connector passing through the hinge assembly is a coaxial cable, the electrical connector may be referred to as a through-axis coaxial cable. By placing the electrical connector through the hinge assembly, signal transmission between the first and second circuit boards is ensured without affecting the electronic device's ability to be unfolded or folded.

[0015] In an optional embodiment, the electrical connector is a flexible printed circuit (FPC), having a bending region and non-bending regions on either side of the bending region; the portion of the electrical connector that passes through the hinge assembly is located in the bending region. The FPC includes a first flexible substrate, a second flexible substrate, a third flexible substrate, a first adhesive layer, and a second adhesive layer. The first flexible substrate includes a first signal trace disposed in the bending region. The second flexible substrate is laminated on a side of the first flexible substrate facing away from the display screen. The second flexible substrate includes a second signal trace disposed in the non-bending region, the second signal trace being electrically connected to the first signal trace. The first adhesive layer is located in the non-bending region and disposed between the first and second flexible substrates, bonding the first and second flexible substrates together. In the bending region, the first and second flexible substrates are non-bonded, for example, with a first air gap. The third flexible substrate is laminated on a side of the second flexible substrate facing away from the first flexible substrate. The second adhesive layer is located in the non-bending region and disposed between the second and third flexible substrates, bonding the second and third flexible substrates together. In the bending region, the third flexible substrate and the second flexible substrate are non-adhesive, for example, having a second air gap. This allows, on the one hand, the non-adhesive, for example, first air gap, between the first flexible substrate and the second flexible substrate, and the non-adhesive, for example, second air gap, between the third flexible substrate and the second flexible substrate in the bending region. This allows the electrical connector to bend in the non-adhesive, for example, air gap, position, providing sufficient space for deformation. This allows the connector to bend more easily in the bending region, thereby increasing its flexibility. Furthermore, in the bending region of the electrical connector, a first signal trace is disposed within the first flexible substrate near the display screen. The reference ground for the first signal trace can be a metal layer of the second flexible substrate. The metal layer of the second flexible substrate is located on one side of the first signal trace. When the electrical connector bends in the bending region, only the distance between the first signal trace and the underlying reference ground changes dynamically, resulting in minimal impedance fluctuations. Furthermore, in the non-bending region of the electrical connector, the second signal trace is disposed in the middle of the second flexible substrate. Therefore, the metal layer of the first flexible substrate above the second signal trace and the metal layer of the third flexible substrate below the second signal trace can both serve as reference grounds for the second signal trace. This reference ground serves as a return signal for the second signal trace, thereby reducing insertion loss.

[0016] In an optional embodiment, the second flexible substrate further includes: a first cover film and a first flexible substrate. The first flexible substrate and the first cover film are stacked together, with the second signal trace disposed between the first cover film and the first flexible substrate. In the bending region, the first cover film and the first flexible substrate are not bonded, for example, a third air gap is provided. In this case, in the bending region of the electrical connector, the first signal trace is disposed within the first flexible substrate near the display screen. Furthermore, the first cover film and the first flexible substrate are not bonded, for example, the third air gap is provided, resulting in the second flexible substrate having no metal layer within the bending region. Therefore, the reference ground for the first signal trace can be the metal layer of the third flexible substrate. In this manner, when the bending region of the electrical connector bends, the metal layer of the third flexible substrate is located on one side of the first signal trace, and the distance between the first signal trace and the metal layer of the third flexible substrate is relatively large. Therefore, dynamic changes in the distance between the first signal trace and the metal layer of the third flexible substrate have a minimal impact on impedance fluctuations of the electrical connector.

[0017] In an optional embodiment, the FPC further includes an electromagnetic shielding layer, which is laminated on the side of the first flexible substrate facing the display screen. The electromagnetic shielding layer can provide a certain shielding effect on electromagnetic waves, thereby reducing the insertion loss of the FPC.

[0018] In an optional embodiment, the electronic device further includes a first battery and a second battery. The first battery is disposed on a side of the first middle frame facing away from the display screen, with the vertical projection of the first battery on the middle frame not overlapping the vertical projection of the first circuit board on the middle frame. The second battery is disposed on a side of the second middle frame facing away from the display screen. When the display screen is flattened, the second circuit board is located on the side of the second battery facing away from the first battery and the first circuit board. In the case of a folding electronic device, the display module of the electronic device is disposed on the second circuit board. To enable the second circuit board to support the display module, the outline of the second circuit board can be similar to the outline of the display module, thereby preventing the width of the second circuit board from being further reduced. Therefore, by arranging the RF circuit on the second circuit board, the space utilization of the component layout on the second circuit board can be improved. At the same time, since the RF circuit does not need to be disposed on the first circuit board, the area of ​​the first circuit board can be reduced. Since the size of the second circuit board cannot be reduced due to the size of the display module, the area of ​​the second battery, which is located on the same middle frame as the second circuit board, cannot be further reduced. Therefore, by arranging the RF circuit on the second circuit board, the RF circuit does not occupy the area of ​​the first circuit board, thereby reducing the size of the first circuit board. Based on this, since the first battery and the first circuit board are both arranged on the first middle frame, when the area of ​​the first circuit board is reduced, the area of ​​the first battery can be increased, thereby increasing the battery capacity of the first battery, thereby achieving the purpose of improving the battery life of the electronic device.

[0019] In an optional embodiment, the electronic device further includes at least one camera, and the camera is arranged between the first circuit board and the second circuit board. Based on this, for the solution of arranging the SoC circuit and the radio frequency circuit on the same circuit board, as the functions of the electronic device continue to improve, the size of the camera will become larger and larger, and the number of electronic components arranged on the circuit board will also increase. In this case, it is necessary to open a larger hole on the circuit board where many electronic components are already arranged to accommodate the larger camera. This will increase the difficulty of opening holes in the circuit board, resulting in an increase in production costs. In the solution provided in the embodiment of the present application, the first circuit board and the second circuit board are arranged at an interval, so that the gap between the first circuit board and the second circuit board can be used to accommodate the above-mentioned camera, thereby eliminating the need to open holes in the circuit board, reducing the difficulty of making the electronic device, simplifying the production process and thus reducing production costs.

[0020] In an optional embodiment, the electrical connector is a flexible circuit board, and the thickness of the electrical connector is less than or equal to 0.2 mm. In this way, the electrical connector stacked on the battery does not occupy a large size, thereby effectively reducing the thickness of the electronic device.

[0021] In an optional embodiment, the electrical connector is a coaxial line with a diameter less than or equal to 0.2 mm. Similarly, the electrical connector stacked on the battery does not occupy a large size, thereby effectively reducing the thickness of the electronic device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a schematic structural diagram of an electronic device provided in an embodiment of the present application;

[0023] FIG2 is a schematic structural diagram of another electronic device provided in an embodiment of the present application;

[0024] FIG3 is a schematic structural diagram of the electronic device shown in FIG2 in a folded state;

[0025] FIG4 is a schematic diagram of a cross-sectional structure of the electronic device shown in FIG2 in a flattened state;

[0026] FIG5 is a schematic diagram of another cross-sectional structure of the electronic device shown in FIG2 in a flattened state;

[0027] FIG6 is a schematic diagram of a partial structure of an electronic device provided in an embodiment of the present application;

[0028] FIG7 is a schematic diagram of a partial structure of another electronic device provided in an embodiment of the present application;

[0029] FIG8 is a schematic structural diagram of another electronic device provided in an embodiment of the present application;

[0030] FIG9 is a schematic diagram of a partial structure of another electronic device provided in an embodiment of the present application;

[0031] FIG10 is a schematic diagram of a partial structure of another electronic device provided in an embodiment of the present application;

[0032] FIG11 is a schematic diagram of a partial structure of another electronic device provided in an embodiment of the present application;

[0033] FIG12 is a schematic diagram of a partial structure of another electronic device provided in an embodiment of the present application;

[0034] FIG13 is a schematic diagram of a transmission link of an electronic device provided in an embodiment of the present application;

[0035] FIG14 is a schematic diagram of another transmission link of an electronic device provided in an embodiment of the present application;

[0036] FIG15 is a schematic diagram of another transmission link of an electronic device provided in an embodiment of the present application;

[0037] FIG16 is a schematic diagram of another transmission link of an electronic device provided in an embodiment of the present application;

[0038] FIG17 is a schematic diagram of another transmission link of an electronic device provided in an embodiment of the present application;

[0039] FIG18 is a schematic diagram of another transmission link of an electronic device provided in an embodiment of the present application;

[0040] FIG19 is a schematic diagram of another partial structure of an electronic device provided in an embodiment of the present application;

[0041] FIG20 is a cross-sectional view taken along the dotted line O1-O2 in FIG19;

[0042] FIG21 is another cross-sectional view taken along the dotted line O1-O2 in FIG19;

[0043] FIG22 is another cross-sectional view taken along the dotted line O1-O2 in FIG19;

[0044] FIG23 is another cross-sectional view taken along the dotted line O1-O2 in FIG19;

[0045] FIG24 is another cross-sectional view taken along the dotted line O1-O2 in FIG19;

[0046] FIG25 is a schematic diagram of the electrical connector in FIG19 in a bent state;

[0047] FIG26 is another cross-sectional view taken along the dotted line O1-O2 in FIG19;

[0048] FIG27 is another cross-sectional view obtained by cutting along the dotted line O1 - O2 in FIG19 .

[0049] Reference numerals:

[0050] 01-Electronic device; 100-Display screen; 101-Middle frame; 102-Rear shell; 1011-First middle frame; 1012-Second middle frame; 1021-First rear shell; 1022-Second rear shell; 200-Hinge assembly; 400-Circuit board assembly; 41-First circuit board; 42-Second circuit board; 30-Electrical connector; 300a-First accommodating space; 300b-Second accommodating space; 103-Additional display screen; 410-SoC circuit; 4101-SoC chip; 4102-RF antenna; 31-First connector; 32-Second connector; 420-RF circuit; 4201-RFIC chip; 4202-RF antenna; 4203-RF front end; 421-Display module; 60-Camera Camera; 61-front camera; 62-rear camera; 72-second low-pass filter circuit; 73-high-pass filter circuit; 700-band-pass filter circuit; 71-first low-pass filter circuit; 301-non-bending area; 302-bending area; 310-first flexible substrate; 320-second flexible substrate; 330-first adhesive layer; 340-air gap; 350-third flexible substrate; 360-second adhesive layer; 3401-first air gap; 3402-second air gap; 3403-third air gap; 3201-first flexible substrate. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0052] In the following, the terms "first," "second," etc., are used for descriptive convenience only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first," "second," etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0053] The limitations such as parallel, perpendicular, orthogonal, identical (for example, identical length, identical width, etc.) mentioned in the embodiments of the present application are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense. There may be a deviation of a predetermined angle between two components that are parallel or perpendicular to each other. In one embodiment, the predetermined threshold value may be less than or equal to a threshold value of 1 mm, for example, the predetermined threshold value may be 0.5 mm, or may be 0.1 mm. In one embodiment, the predetermined angle may be an angle within a range of ±10°, for example, the predetermined angle deviation is ±5°.

[0054] In this application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, "connection" can be a fixed mechanical connection, a detachable mechanical connection, or an integrated one; or, "connection" can be a direct connection, or an indirect connection through an intermediate medium. In addition, unless otherwise clearly specified and limited, the term "coupling" should be understood in a broad sense, for example, "coupling" can be a direct electrical connection, for example, physical contact and electrical conduction between two components, or it can be understood as the electrical connection between different components in the circuit structure through a physical line that can transmit electrical signals such as printed circuit board (PCB) copper foil or wire to transmit electrical signals for the purpose of transmitting electrical signals; or, "coupling" can be an indirect electrical connection between two components through an intermediate medium; or, "coupling" can be an electrical connection between two components in an airless / non-contact manner, for example, two components are electrically connected by capacitive coupling to transmit electrical signals.

[0055] In the embodiments of the present application, directional terms such as "up", "down", "left" and "right" may be defined including but not limited to the orientation relative to the components schematically placed in the drawings. It should be understood that these directional terms may be relative concepts, which are used for relative description and clarification, and may change accordingly according to changes in the orientation of the components in the drawings.

[0056] In the drawings of the embodiments of the present application, components are represented by guide lines with arrows; parts are represented by guide lines only; openings, holes and the like are represented by guide lines with wavy lines at the ends.

[0057] The technical solution provided in the embodiments of the present application is applicable to electronic devices that adopt one or more of the following communication technologies. The above-mentioned communication protocols may include: Bluetooth (BT) communication technology, global positioning system (GPS) communication technology, global system of mobile communication (GSM) communication technology, wireless fidelity (WiFi) communication technology, wideband code division multiple access wireless (WCDMA) communication technology, long term evolution (LTE), 5G communication technology and other future communication technologies.

[0058] The electronic device in the embodiments of the present application can be a mobile phone, a tablet computer (pad), a laptop computer, a smart home, a smart wearable device (for example, a smart watch, a smart bracelet, smart glasses, a smart helmet), a virtual reality (VR) electronic device, an augmented reality (AR) electronic device, etc. The electronic device can also be a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, an in-vehicle device, an electronic device in a 5G network, or an electronic device in a public land mobile network (PLMN) to be evolved in the future, etc., and the embodiments of the present application are not limited to this. For the convenience of explanation, the following is an example of an electronic device being a mobile phone or a tablet computer. The mobile phone or tablet computer can be a straight-screen phone or a folding phone, and the present application does not limit this.

[0059] In some embodiments, as shown in FIG1 , the electronic device 01 provided in the embodiment of the present application may include a display screen 100, a rear case 102 located behind the display screen 100 (arranged opposite to the display surface of the display screen 100), and a middle frame 101 located between the display screen 100 and the rear case 102. The middle frame 101 can support the display screen 100, and an accommodating space (not shown in the figure) can be formed between the middle frame 101 and the rear case 102.

[0060] Figure 1 illustrates an example of a candy bar device. To facilitate the description of the candy bar device structure, an XYZ coordinate system is established in Figure 1, wherein the XY plane can be parallel to the display surface of the display screen 100. If the outline of the electronic device 01 is rectangular, the direction of the X-axis can be consistent with the direction of the short side of the outline of the electronic device 01, and the direction of the Y-axis can be consistent with the direction of the long side of the outline of the electronic device 01. The Z-axis is perpendicular to the XY plane and can be the stacking direction of the rear housing 102, the middle frame 101, and the display screen 100, that is, the thickness direction of the electronic device 01.

[0061] In other embodiments of the present application, the electronic device 01 may be a folding device as shown in FIG2 , and the electronic device 01 may include two middle frames and two rear shells. The two middle frames are respectively a first middle frame 1011 and a second middle frame 1012, and the two rear shells are respectively a first rear shell 1021 and a second rear shell 1022. In addition, the electronic device 01 may further include a hinge assembly 200, which is located between the first middle frame 1011 and the second middle frame 1012. The hinge assembly 200 may be connected to the first middle frame 1011 and the second middle frame 1012, so that the first middle frame 1011 is rotatably connected to the second middle frame 1012 via the hinge assembly 200.

[0062] In order to facilitate the description of the structure of the folding machine, an XYZ coordinate system is established in Figure 2, wherein, when the electronic device 01 is in a flat state, the XY plane can be parallel to the display surface of the display screen 100. The direction of the X axis can be consistent with the direction in which the first middle frame 1011 points to the second middle frame 1012 (or the direction in which the second middle frame 1012 points to the first middle frame 1011). In the case where the outline shape of the first middle frame 1011 or the second middle frame 1012 is rectangular, the direction of the Y axis is consistent with the direction in which the long side of the outline shape of the first middle frame 1011 or the second middle frame 1012 is located. When the electronic device 01 is in a flat state, the Z axis is perpendicular to the above-mentioned XY plane. The Z axis can be the stacking direction of the first rear shell 1021, the first middle frame 1011 and the display screen 100, that is, the thickness direction of the electronic device 01 in the flat state.

[0063] In some embodiments, the folding method of the above-mentioned folder can be an inward folding method, that is, the folder is in a folded state, so that after the first rear shell 1021 and the second rear shell 1022 are folded in half, as shown in Figure 3, the display screen 100 is located between the folded first and second rear shells 1021, 1022. Alternatively, in other embodiments, the folding method of the above-mentioned folder can be an outward folding method, that is, the folder is in a folded state, so that after the first and second rear shells 1021, 1022 are folded in half, the display screen 100 is wrapped around the outside of the folded first and second rear shells 1021, 1022. This application does not limit the folding method of the folder. For the convenience of explanation, the following examples are all based on the inward folding method of the folder.

[0064] Based on this, as shown in Figure 4, the first rear shell 1021 and the first middle frame 1011 are stacked on the same side of the hinge assembly 200, and a first accommodating space 300a can be formed between the above-mentioned first rear shell 1021 and the first middle frame 1011, and the second rear shell 1022 and the second middle frame 1012 are stacked on the same side of the hinge assembly 200, and a second accommodating space 300b can be formed between the above-mentioned second rear shell 1022 and the second middle frame 1012.

[0065] In other embodiments of the present application, the second rear shell 1022 (or the first rear shell 1021) shown in Figure 2 or Figure 4 can also be replaced with an additional display screen 103 as shown in Figure 5, and the display surface of the additional display screen 103 is set away from the first middle frame 1011 or the second middle frame 1012. When the folding machine is in the folded state, the display surface of the display screen 100 is located on the inner side, and the display surface of the additional display screen 103 is located on the outer side. In this way, the folding machine can display images through the additional display screen 103 when in the folded state. In the unfolded state, images can be displayed through the display screen 100 and / or the additional display screen 103. Based on this, in Figure 5, the second middle frame 1012 and the additional display screen 103 can form the above-mentioned second accommodating space 300b.

[0066] This application does not limit the number of display screens in a folding device. For ease of explanation, the following examples are based on the folding device shown in Figures 2 or 4, where the device has a single display screen 100. Furthermore, in the embodiments of this application, the folded state of the folding device refers to a state where the angle α between the first middle frame 1011 and the second middle frame 1012 is less than 180°, i.e., α < 180°, as shown in Figure 3. When the folding device is in the fully folded state, α can be equal to or approximately equal to 0°. Furthermore, the flattened state of the folding device refers to a state where the aforementioned angle α = 180°.

[0067] On this basis, for the electronic device 01 shown in Figure 1, Figure 4 or Figure 5, the electronic device 01 may further include a processor electrically connected to the display screen 100, and the processor may be arranged in the accommodation space formed between the above-mentioned middle frame and the rear shell (for example, the first accommodation space 300a and the second accommodation space 300b shown in Figure 4). In addition, the above-mentioned accommodation space may also be used to accommodate the above-mentioned circuit board, battery and other devices. The processor may provide display data to the display screen 100 to drive the display screen 100 to display an image. For example, the above-mentioned processor may include one or more processing units, for example: the processor may include a system on a chip (SoC), an application processor (AP), a modem, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc. Among them, different processing units may be independent devices or integrated into one or more processors.

[0068] In addition, the electronic device 01 may further include an external memory interface electrically connected to the processor, an internal memory, a universal serial bus (USB) interface, a charging management module, a power management module, a battery, an antenna, a mobile communication module, a wireless communication module, an audio module, a speaker, a receiver, a microphone, an earphone interface, a sensor module, buttons, and a camera, etc. The sensor module may include a pressure sensor, a gyroscope sensor, an air pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a proximity light sensor, a fingerprint sensor, a temperature sensor, a touch sensor, an ambient light sensor, and a bone conduction sensor, etc.

[0069] In some embodiments of the present application, when the electronic device 01 is the folding machine, as shown in FIG4 , the electronic device 01 may include a circuit board assembly 400. The circuit board assembly 400 may include at least two circuit boards, such as a first circuit board 41 and a second circuit board 42. Any one of the first circuit board 41 and the second circuit board 42 may be used to electrically connect to components such as the processor or battery. The first circuit board 41 may be disposed in the first accommodating space 300 a, and the second circuit board 42 may be disposed in the second accommodating space 300 b, so that the first circuit board 41 and the second circuit board 42 can be spaced apart. When the electronic device 01 is the folding machine, the hinge assembly 200 may be disposed between the first circuit board 41 and the second circuit board 42. For example, the first circuit board 41 and the second circuit board 42 may be PCBs.

[0070] Based on this, as shown in Figure 4 , in order to electrically connect the first circuit board 41 and the second circuit board 42, the circuit board assembly 400 may further include an electrical connector 30. One end of the electrical connector 30 may be located within the first accommodating space 300a and electrically connected to the first circuit board 41. The other end of the electrical connector 30 may be located within the second accommodating space 300b and electrically connected to the second circuit board 42. In this way, electronic components on the first circuit board 41 can establish signal communication with electronic components on the second circuit board 42 through the first circuit board 41, the electrical connector 30, and the second circuit board 42.

[0071] On this basis, as shown in Figure 4, when the electronic device 01 has a hinge assembly 200, a portion of the electrical connector 30 can be set through the hinge assembly 200. For example, the electrical connector 30 can be a flexible printed circuit (FPC) or a coaxial line. Based on this, when the electrical connector 30 set through the hinge assembly 200 is an FPC, the electrical connector 30 can be called a through-axis FPC. Alternatively, when the electrical connector 30 set through the hinge assembly 200 is a coaxial line, the electrical connector 30 can be called a through-axis coaxial line. In this way, by setting the electrical connector 30 through the axis, the signal transmission between the first circuit board 41 and the second circuit board 42 can be guaranteed without affecting the flattened and folded usage state of the electronic device 01.

[0072] As can be seen from the above, electronic devices are provided on the first circuit board 41 and the second circuit board 42. The electronic devices are described below by way of example. For example, in some embodiments of the present application, as shown in FIG6 , the circuit board assembly 400 may further include a SoC circuit 410 provided on the first circuit board 41 and a radio frequency (RF) circuit 420 provided on the second circuit board 42. The SoC circuit 410 is electrically connected to the first circuit board 41, and the RF circuit 420 is electrically connected to the second circuit board 42.

[0073] In some embodiments of the present application, as shown in FIG6 , the SoC circuit 410 may include a SoC chip 4101 and a clock chip 4102 electrically connected to the SoC chip 4101. The SoC chip 4101 may include an AP and a modem. In addition, the RF circuit 420 may include a RF integrated circuit (IC) 4201 and a RF antenna 4202 electrically connected to the RFIC 4201.

[0074] For example, the communication protocols that can be adopted by the above-mentioned RF antenna 4202 may include: Bluetooth (BT) communication technology, global positioning system (GPS) communication technology, global system of mobile communication (GSM) communication technology, wireless fidelity (WIFI) communication technology, wideband code division multiple access wireless (WCDMA) communication technology, long term evolution (LTE), 5G communication technology and other future communication technologies.

[0075] In other embodiments, as shown in FIG6 , the RF circuit 420 may further include an RF front end 4203, which may be electrically connected between the RFIC 4201 and the RF antenna 4202. The RF front end 4203 may include a power amplifier (PA), an antenna switch, a tuner, a filter, a duplexer or a multiplexer, and a low noise amplifier (LNA). The present application does not limit the structure of the RF front end 4203.

[0076] Based on this, as shown in Figure 6, in order to enable the electrical connector 30 to be electrically connected to the SoC circuit 410, the electronic device 01 may further include a first connector 31 provided on the first circuit board 41. The first connector 31 may be electrically connected to the first circuit board 41 by welding or other means. In addition, the end of the electrical connector 30 facing the first circuit board 41 may be plugged into the first connector 31, so that the electrical connector 30 is electrically connected to the first connector 31.

[0077] Similarly, in order to enable the electrical connector 30 to be electrically connected to the RF circuit 420, the circuit board assembly 400 may further include a second connector 32 disposed on the second circuit board 42. The second connector 32 may be connected to the second circuit board 42 by welding or other methods. In addition, the end of the electrical connector 30 facing the second circuit board 42 may be plugged into the second connector 32 to electrically connect the electrical connector 30 to the second connector 32.

[0078] In other embodiments of the present application, when the electrical connector 30 is an FPC, the first connector 31 and the second connector 32 may be removed from the transmission line, and the FPC may be directly electrically connected to the first circuit board 41 and the second circuit board 42 .

[0079] In this case, as shown in Figure 6, the first circuit board 41, the first connector 31, the electrical connector 30, the second connector 32, and the second circuit board 42 can form a transmission link between the SoC circuit 410 and the RF circuit 420. In this way, the SoC chip 4101 in the SoC circuit 410 can be electrically connected to the first connector 31 via the metal traces on the first circuit board 41, so that the SoC chip 4101 can output signals to the RFIC 4201 in the RF circuit 420, or the SoC chip 4101 can receive signals from the RFIC 4201 via the above transmission link. Similarly, the clock chip 4102 in the SoC circuit 410 can provide an RF reference clock via the above transmission link.

[0080] In comparison, in the related art, as shown in FIG7 , the SoC circuit and the RF circuit are arranged on the same PCB. The SoC circuit is used to perform computations and processing on various signals. The SoC circuit is prone to heat generation during operation, and therefore the SoC circuit can be one of the main heat sources in the electronic device. In addition, the RF circuit is also prone to generate heat during operation. For example, the power amplifier of the RF front end in the RF circuit can be one of the main heat sources of the RF circuit. Therefore, when the SoC circuit and the RF circuit are arranged on the same PCB as shown in FIG7 , the heat sources are concentrated, which can cause severe local heating of the electronic device 01. For example, in the case where the electronic device 01 is a folding device, when the folding device is in a folded state, the heat dissipation conditions deteriorate, which can cause the local temperature of the electronic device 01 to rise rapidly, resulting in abnormal phenomena such as abnormal application exit or inability to operate normally in the electronic device 01, thereby reducing the performance of the electronic device 01.

[0081] Therefore, when the electronic device 01 provided in the embodiment of the present application is a folding machine, in the electronic device 01, as shown in Figure 6, by respectively arranging the components that serve as the main heat sources of the electronic device 01, such as the SoC circuit 410 and the radio frequency circuit 420, on a first circuit board 41 and a second circuit board 42 that are independent of each other and spaced apart, it is possible to avoid the heat sources being concentrated on the same circuit board, thereby reducing the probability of excessive local heat in the electronic device 01 and improving the performance of the electronic device 01.

[0082] In the above embodiment, there is no limitation on the shapes of the first circuit board 41 and the second circuit board 42. In other embodiments of the present application, the layout positions and shapes of the first circuit board 41 and the second circuit board 42 are exemplified in combination with the layout positions of other components in the electronic device 01.

[0083] In some embodiments of the present application, when the electronic device 01 is a folding device, as shown in FIG8 , the electronic device 01 may include a display module 421, in which a display driving circuit is provided. The display module 421 may be electrically connected to the display screen 100, and the display module 421 provides a display driving signal to the display screen 100 to drive the display screen 100 to display. For example, the display module 421 may be provided on the second circuit board 42, and the display module 421 may be electrically connected to the second circuit board 42. In addition, as shown in FIG9 , the electronic device 01 may further include a first screen connector provided on the second circuit board 42, and the first screen connector may be electrically connected to the display module 421 and the display screen 100 shown in FIG8 , so that the display screen 100 may be electrically connected to the display module 421 via the first screen connector.

[0084] Based on this, as shown in Figure 8, the display module 421 has a certain width D1 along the X direction, and the example D1 can be more than 10 mm. In order to enable the second circuit board 42 to carry the display module 421, the contour shape of the second circuit board 42 can be similar to the contour shape of the display module 421, for example, both are long strips. The width D0 of the second circuit board 42 along the X direction also needs to be set to more than 10 mm, so that the width D0 of the second circuit board 42 along the X direction cannot be further reduced. As shown in Figure 9, by arranging the radio frequency circuit 420 on the second circuit board 42, the space utilization rate of the component layout on the second circuit board 42 can be improved. At the same time, since the radio frequency circuit 420 does not need to be set on the first circuit board 41, the area of ​​the first circuit board 41 can be reduced.

[0085] Based on this, in some embodiments of the present application, as shown in Figure 9, the electronic device 01 may further include two batteries, namely a first battery 51 and a second battery 52. ​​The first battery 51 is arranged on the side of the first middle frame 1011 away from the display screen 100 (as shown in Figure 8). Along the Y direction, the first battery 51 can be arranged side by side with the first circuit board 41, that is, the vertical projection of the first battery 51 on the first middle frame 1011 and the vertical projection of the first circuit board 41 on the first middle frame 1011 do not overlap. In addition, the second battery 52 can be arranged on the side of the second middle frame 1012 away from the display screen 100 (as shown in Figure 8). When the display screen 100 is in a flattened state, the second circuit board 42 is located on the side of the second battery 52 away from the first battery 51 and the first circuit board 41.

[0086] As can be seen from the above, as shown in Figure 9 , the size of the second circuit board 42 cannot be reduced due to the size of the display module 421 shown in Figure 8 . Consequently, the area of ​​the second battery 52 located in the same middle frame as the second circuit board 42, such as on the second middle frame 1012, cannot be further reduced. In comparison, in the related art, as shown in Figure 10 , both the RF circuit and the SoC circuit are disposed on PCB 1. Consequently, in order for the PCB to carry the RF circuit and the SoC circuit, as well as other circuits or chips, PCB 1 needs to be larger, resulting in PCB 1 occupying a larger layout space.

[0087] However, in the solution provided by the embodiment of the present application, as shown in FIG9 , by setting the RF circuit 420 on the second circuit board 42, the RF circuit 420 does not need to occupy the area of ​​the first circuit board 41, thereby reducing the size of the first circuit board 41. Based on this, since the first battery 51 and the first circuit board 41 are both set on the first middle frame 1011, and the vertical projection of the first battery 51 on the first middle frame 1011 does not overlap with the vertical projection of the first circuit board 41 on the first middle frame 1011, when the area of ​​the first circuit board 41 is reduced, the space occupied by the first circuit board 41 in the first middle frame 1011 can be reduced, thereby increasing the layout space for other components on the first middle frame 1011, such as the first battery 51, which is conducive to increasing the area of ​​the first battery 51 and thus increasing the battery capacity of the first battery 51, thereby achieving the purpose of improving the battery life of the electronic device 01. For example, as shown in FIG9 , the size of the first battery 51 along the Y direction can be increased so that the size of the first battery 51 along the Y direction is L1. 10 , L1 > L2. Alternatively, in other embodiments of the present application, the size of the first battery 51 along the X direction may be increased to increase the battery capacity of the first battery 51.

[0088] The above description is based on the example of the display module 421 shown in FIG8 being disposed on the second circuit board 42. In other embodiments of the present application, the display module 421 may also be disposed on the first circuit board 41. Similarly, in this way, the size of the second circuit board 42 can be reduced, thereby increasing the area and battery capacity of the second battery 52.

[0089] For example, as shown in Figure 9 , at least one of the first battery 51 and the second battery 52 can be charged via a USB cable. Alternatively, in other embodiments, the electronic device 01 can further include a wireless charging coil 510 , which can be located on the first battery 51 or the second battery 52 , although this application does not limit this. In this way, the wireless charging coil 510 can be used to wirelessly charge at least one of the first battery 51 and the second battery 52 .

[0090] As can be seen from the above, as shown in Figure 9, the SoC circuit 410 located on the first circuit board 41 can be electrically connected to the RF circuit 420 located on the second circuit board 42 through the electrical connector 30. In some embodiments of the present application, in order to improve space utilization in the electronic device 01, the electrical connector 30 can be stacked with some electronic components, such as the second battery 52, so that the electrical connector 30 and the second battery 52 can be stacked in the thickness direction of the electronic device 01 (parallel to the XY plane), avoiding the electrical connector 30 occupying the area of ​​the XY plane.

[0091] In this case, in order to reduce the thickness of the electronic device 01, when the electrical connector 30 is an FPC, the thickness of the electrical connector 30 can be less than or equal to 0.2 mm. For example, the thickness of the dielectric layer or metal layer in the FPC can be thinned. As a result, the electrical connector 30 stacked on the battery, such as the second battery 52, does not occupy a large size, thereby effectively reducing the thickness of the electronic device 01. Similarly, when the electrical connector 30 is a coaxial cable, the diameter of the coaxial cable can be less than or equal to 0.2 mm. In this case, the coaxial cable can be called an ultra-fine coaxial cable. The technical effect of the ultra-fine coaxial cable is the same as described above and will not be repeated here.

[0092] In addition, as shown in Figure 9, the electronic device 01 may also include other electronic devices, such as: a first front camera, a rear camera, an additional antenna (such as a WIFI antenna, or a Bluetooth antenna, etc.), sensors, etc., and the above components may be arranged on the first circuit board 41. The light-receiving surface of the first front camera may be located on the same side as the display surface of the display screen 100. In this way, when the folding mode of the electronic device 01 is inward folding, the first front camera may be called an inner-screen front camera. Alternatively, when the folding mode of the electronic device 01 is outward folding, the first front camera may be called an outer-screen front camera. In addition, the electronic device 01 may also include a motor, and the motor and the USB may be arranged on another independent PCB, which may be located on the first middle frame 1011.

[0093] On this basis, when the electronic device 01 further includes the additional display screen 103 as shown in FIG4 , as shown in FIG9 , the electronic device 01 may further include a second screen connector for electrically connecting the additional display screen 103 to the second circuit board 42. In addition, the electronic device 01 may further include a second front-facing camera, an earpiece, a speaker, and a subscriber identity module (SIM) card or a secure digital card (SD) card (not shown).

[0094] Among them, the light-receiving surface of the second front camera can be located on the same side as the display surface of the additional display screen 103 (as shown in FIG4 ). When the folding mode of the electronic device 01 is inward folding, the additional display screen 103 is an external screen, and the second front camera can be called an external screen front camera. Alternatively, when the folding mode of the electronic device 01 is outward folding, the additional display screen 103 is an internal screen, and the second front camera can be called an internal screen front camera. In addition, the above-mentioned earpiece, speaker and second front camera can be located on the second middle frame 1012. In addition, the sensor on the second circuit board 42 can be the same as or different from the sensor on the first circuit board 41, and this application does not limit this. The above is an example of the camera, sensor, motor, earpiece and other components in the electronic device 01 when the electronic device 01 is a folding machine, and does not constitute a limitation on the number and position layout of the above-mentioned components.

[0095] The above embodiment takes the electronic device 01 as a folding machine as an example, and illustrates that the two main heat sources in the electronic device 01, namely the SoC circuit 410 and the radio frequency circuit 420, are respectively arranged on two independent (for example, spaced apart) circuit boards, such as the first circuit board 41 and the second circuit board 42. In other embodiments of the present application, as shown in Figure 11, when the electronic device 01 is a straight-screen machine, the electronic device 01 has only one middle frame, namely the first middle frame 1011. Based on this, in the straight-screen machine, the SoC circuit 410 and the radio frequency circuit 420, which are the main heat sources, can still be arranged on the first circuit board 41 and the second circuit board 42, respectively. In this way, the problem of excessive local heat caused by the heat sources being concentrated on the same circuit board in the straight-screen machine can also be solved.

[0096] Among them, the structure, setting method and technical effect of the SoC circuit 410 and the radio frequency circuit 420 are the same as described above and will not be repeated here. In addition, as shown in Figure 11, the electronic device 01 may also include electronic devices such as sensors, WIFI / Bluetooth antennas, screen connectors, USB, motors, speakers and SIM / SD cards. This application does not limit the setting method of the above-mentioned electronic devices. Figure 11 is only an example of the layout method of the above-mentioned electronic devices. In addition, in other embodiments of the present application, the battery of the electronic device 01 as a straight-screen machine can be charged by wire through a USB interface, or the electronic device 01 may include a wireless charging coil 510 as shown in Figure 9, so that the battery can be charged by wireless charging.

[0097] In addition, in some embodiments of the present application, as shown in FIG11 , the electronic device 01 may further include at least one camera 60. For example, the electronic device 01 may include two cameras, namely a front camera 61 and a rear camera 62. Based on this, the cameras 60 (including the front camera 61 and the rear camera 62) may be disposed between the first circuit board 41 and the second circuit board 42.

[0098] In comparison, in the related art, as shown in FIG12 , the SoC circuit and the radio frequency circuit are arranged on the same circuit board. Therefore, as the functions of electronic devices continue to improve, the size of the camera will become larger and larger, and the number of electronic components arranged on the circuit board will also increase. In this case, it is necessary to open a larger hole on the circuit board where many electronic components are already arranged to accommodate the larger camera. This will increase the difficulty of opening the hole in the circuit board, resulting in an increase in production costs. However, in the solution provided in the embodiment of the present application, as shown in FIG11 , the first circuit board 41 and the second circuit board 42 are arranged at an interval. In this way, the gap between the first circuit board 41 and the second circuit board 42 can be used to accommodate the above-mentioned camera 60, so that there is no need to open a hole in the circuit board, which reduces the difficulty of making the electronic device 01, simplifies the production process, and thus reduces production costs.

[0099] On this basis, since the SoC circuit 410 and the RF circuit 420 are respectively provided on the first circuit board 41 and the second circuit board 42, the SIM card and the RF circuit 420 can be provided on the same circuit board, namely, the aforementioned second circuit board 42. In this way, the same production process can be used to manufacture electronic devices 01 of the same batch with different performance requirements. For example, the same process can be used to manufacture electronic devices 01. During the final assembly process, if the electronic device 01 does not require a call function, the second circuit board 42 provided with the SIM card and the RF circuit 420 can be removed from the electronic device 01. When the electronic device 01 has a call function, the second circuit board 42 provided with the SIM card and the RF circuit 420 can be installed in the electronic device 01. In this way, most of the manufacturing processes for the electronic devices 01 of different forms described above are the same. During the assembly process, the second circuit board 42 only needs to be selectively assembled as needed, eliminating the need to set different manufacturing processes for electronic devices 01 with different performance requirements, thereby simplifying the manufacturing process and saving costs.

[0100] As can be seen from the above, for the folding device shown in FIG9 or the candy bar device shown in FIG11, when the electronic device 01 has a radio frequency circuit 420, as shown in FIG6, the clock signal output by the clock chip 4102 in the SoC circuit 410 will be transmitted to the RFIC chip 4201 in the radio frequency circuit 420 via the above-mentioned transmission link (including the first circuit board 41, the first connector 31, the electrical connector 30, the second connector 32, and the second circuit board 42). Specifically, the clock chip 4102 can serve as the input end of the above-mentioned transmission link, and the RFIC chip 4201 can serve as the output end of the transmission link.

[0101] In this case, because the RF antenna 4202 in the RF circuit 420 and the wireless charging coil 510 shown in FIG9 can transmit electromagnetic waves, at least one of the RF antenna 4202 and the wireless charging coil 510 can act as an interference source and interfere with the RF reference clock (provided by the clock chip 4102) in the above-mentioned transmission link through the electrical connector 30 shown in FIG13. For example, when the isolation between the RF reference clock and the wireless charging coil 510 is required to be approximately -120 dB, and the isolation between the RF reference clock and the RF antenna 4202 is required to be approximately -100 dB, even if the first connector 31, electrical connector 30, and second connector 32 with better transmission performance are selected, it is difficult to achieve the above isolation requirements.

[0102] Based on this, in some embodiments of the present application, in order to reduce the interference caused by the above-mentioned interference source through the electrical connector 30 and the second connector 32 to the RF reference clock on the portion of the transmission link close to the RFIC chip 4201, and to reduce the interference source from entering the RFIC chip 4201 through the electrical connector 30 and the second connector 32 and affecting the performance of the RFIC chip 4201, the above-mentioned circuit board assembly 400 may further include a second low-pass filter circuit 72 as shown in FIG13 . The second low-pass filter circuit 72 may be electrically connected between the RFIC chip 4201 and the electrical connector 30. For example, in the case where the electronic device includes the second connector 32, the second low-pass filter circuit 72 may be electrically connected between the RFIC chip 4201 and the second connector 32.

[0103] The cutoff frequency of the second low-pass filter circuit 72 can be the starting frequency f11 of the operating frequency band of the RF antenna 4202. In this way, the second low-pass filter circuit 72 can filter out signals having a frequency of the starting frequency f11 of the operating frequency band of the RF antenna 4202 and frequencies above the starting frequency f11 (i.e., ≥ f11). This can reduce the interference of noise from the RF antenna 4202 with the RF reference clock on the portion of the transmission link close to the RFIC chip 4201 through the electrical connector 30 and the second connector 32, and can also reduce the impact of the noise entering the RFIC chip 4201 on the performance of the RFIC chip 4201. In this embodiment of the present application, the starting frequency of an electronic device refers to the minimum frequency among the operating frequencies of the electronic device, such as the RF antenna 4202.

[0104] In other embodiments of the present application, as can be seen from the above, the wireless charging coil 510 can also transmit electromagnetic waves. Therefore, the wireless charging coil 510 can also serve as an interference source. The noise generated by this interference source can pass through the electrical connector 30 and the second connector 32 shown in Figure 13, interfering with the RF reference clock in the portion of the transmission link near the RFIC chip 4201 and affecting the performance of the RFIC chip 4201. Therefore, to address the above problem, the electronic device 01 can also include a high-pass filter circuit 73 as shown in Figure 14. The high-pass filter circuit 73 can be electrically connected between the RFIC chip 4201 and the electrical connector 30. Similarly, when the electronic device includes the second connector 32, the high-pass filter circuit 73 can be electrically connected between the RFIC chip 4201 and the second connector 32.

[0105] Based on this, the cutoff frequency of the high-pass filter circuit 73 can be the end frequency f22 of the operating frequency band of the wireless charging coil 510. In this way, the high-pass filter circuit 73 can filter out signals with frequencies equal to or below the end frequency f22 (i.e., ≤ f22) of the operating frequency band of the wireless charging coil 510. This reduces interference from noise from the wireless charging coil 510 through the electrical connector 30 and the second connector 32 with the RF reference clock in the portion of the transmission link near the RFIC chip 4201. Furthermore, this reduces the impact of this noise on the performance of the RFIC chip 4201 after it enters the RFIC chip 4201.

[0106] In the embodiment of the present application, the cutoff frequency of the electronic device refers to the maximum frequency among the operating frequencies of the electronic device, such as the wireless charging coil 510. Furthermore, in the embodiment of the present application, the low-pass filter circuit can block signals with a frequency higher than or equal to a certain frequency, such as frequency f11, from passing through. Frequency f11 can be the cutoff frequency of the low-pass filter circuit. The high-pass filter circuit can block signals with a frequency lower than or equal to a certain frequency, such as frequency f22, from passing through. Frequency f22 can be the cutoff frequency of the high-pass filter circuit.

[0107] On this basis, when the electronic device 01 includes a second low-pass filter circuit 72 and a high-pass filter circuit 73 as shown in FIG14 , the second low-pass filter circuit 72 and the high-pass filter circuit 73 can be connected in series between the RFIC chip 4201 and the second connector 32. For example, the second low-pass filter circuit 72 can be provided close to the second connector 32, and the high-pass filter circuit 73 can be provided close to the RFIC chip 4201. Alternatively, for another example, the high-pass filter circuit 73 can be provided close to the second connector 32, and the second low-pass filter circuit 72 can be provided close to the RFIC chip 4201. This application does not limit this.

[0108] Based on this, since the operating frequency band of the wireless charging coil 510 is lower than the operating frequency band of the RF antenna 4202, as can be seen from the above, the second low-pass filter circuit 72 can filter out frequencies above the starting frequency f11 of the RF antenna 4202, and the high-pass filter circuit 73 can filter out frequencies below the ending frequency f22 of the wireless charging coil 510. Therefore, the high-pass filter circuit 73 and the second low-pass filter circuit 72 connected in series as shown in Figure 14 can form a bandpass filter circuit 700, and the passband frequency band of the bandpass filter circuit 700 can be f22 to f11, where f22 < f11. In this way, the isolation between the RF antenna 4202 and the RFIC chip 4201, as well as the isolation between the wireless charging coil 510 and the RFIC chip 4201, can be improved by using the bandpass filter circuit 700.

[0109] The following is an example of how the high-pass filter circuit 73 and the second low-pass filter circuit 72 are set up. For example, as shown in Figure 15, the second low-pass filter circuit 72 may include at least one capacitor C and an inductor L, and a group of capacitors C and inductors L connected in series may constitute a first-order LC filter circuit. Figure 15 is an example of the second low-pass filter circuit 72 including a third-order LC filter circuit. In this case, the filtering depth of the second low-pass filter circuit 72 can reach more than 40dB. Alternatively, for another example, the second low-pass filter circuit 72 may be a filter device manufactured using a low temperature co-fired ceramic (LTCC) process, a surface acoustic wave (SAW) process, or an integrated passive device (IPD) process.

[0110] In addition, as shown in FIG. 15 , for example, the high-pass filter circuit 73 may include a capacitor C0 , which may have a low-frequency suppression characteristic, thereby enabling the high-pass filter circuit 73 to filter out frequencies below the termination frequency f22 of the wireless charging coil 510 .

[0111] As can be seen from the above, by providing the high-pass filter circuit 73 and the second low-pass filter circuit 72 before the input of the RFIC chip 4201, noise from noise sources (RF antenna 4202 and wireless charging coil 510) can be reduced, thereby reducing interference with the RF reference clock in the portion of the transmission link close to the RFIC chip 4201 and minimizing the impact on the performance of the RFIC chip 4201. However, the impact of noise sources on the performance of the RFIC chip 4201 is not solely the result of direct interference with the RFIC chip 4201. Within the entire transmission link (including the first circuit board 41, the first connector 31, the electrical connector 30, the second connector 32, and the second circuit board 42), if noise from the noise sources is transmitted to the clock chip 4102 through the electrical connector 30 and the first connector 31 as shown in FIG. 16, this noise will mix with the clock source of the clock chip 4102, generating a low-frequency interference signal at a frequency close to the clock frequency. This low-frequency interference signal can also interfere with the RF reference clock in the portion of the transmission link close to the clock chip 4102.

[0112] To solve the above problem, in some embodiments of the present application, the circuit board assembly 400 may further include a first low-pass filter circuit 71 as shown in FIG16 . The first low-pass filter circuit 71 may be electrically connected between the clock chip 4102 and the electrical connector 30 . Similarly, when the electronic device includes a first connector 31 , the first low-pass filter circuit 71 may be electrically connected between the clock chip 4102 and the first connector 31 . In addition, the cutoff frequency of the first low-pass filter circuit 71 is the starting frequency f11 of the operating frequency band of the RF antenna 4202 . Similarly, the first low-pass filter circuit 71 can filter out signals having a frequency that is the starting frequency f11 of the operating frequency band of the RF antenna 4202 and frequencies above the starting frequency f11 (i.e., ≥ f11), thereby reducing the interference caused by noise from the RF antenna 4202 through the electrical connector 30 and the first connector 31 on the RF reference clock on the portion of the transmission link close to the clock chip 4102 .

[0113] Similarly, the first low-pass filter circuit 71 may include at least one capacitor C and one inductor L, as shown in FIG17 . A series connection of capacitors C and inductors L may constitute a first-order LC filter circuit. FIG17 illustrates an example in which the first low-pass filter circuit 71 may include a two-order LC filter circuit. Alternatively, for example, the first low-pass filter circuit 71 may be a filter device fabricated using an LTCC process, a SAW process, or an IPD process.

[0114] On this basis, in other embodiments of the present application, as shown in FIG18 , the first low-pass filter circuit 71 can be provided between the clock chip 4102 and the first connector 31 to reduce the interference caused by noise from the RF antenna 4202 through the electrical connector 30 and the first connector 31 to the RF reference clock on the portion of the transmission link close to the clock chip 4102. Furthermore, providing a bandpass filter circuit 700 between the second connector 32 and the RFIC 4201 can reduce the interference caused by noise from the RF antenna 4202 and the wireless charging coil 510 through the electrical connector 30 and the second connector 32 to the RF reference clock on the portion of the transmission link close to the RFIC chip 4201, thereby reducing the impact of such noise on the performance of the RFIC chip 4201. On the other hand, even if the noise from the wireless charging coil 510 enters the clock chip 4102 through the first connector 31 and the electrical connector 30, since the noise of the wireless charging coil 510 is low-frequency noise (the maximum frequency is around f22), the low-frequency noise will pass through the first connector 31, the electrical connector 30, the second connector 32, and the second low-pass filter circuit 72 in sequence, and will be filtered out by the high-pass filter circuit 73, so that it will not enter the RFIC chip 4201, and will not affect the performance of the RFIC chip 4201.

[0115] Therefore, by providing the first low-pass filter circuit 71, the second low-pass filter circuit 72, and the high-pass filter circuit 73 in the transmission link, it is possible to reduce the occurrence of bidirectional interference caused by the interference source through the electrical connector 30, the first connector 31, the second connector 32, the clock chip 4102, and the RFIC chip 4201. In addition, the above description is based on an example in which the transmission link includes the first connector 31 and the second connector 32.

[0116] The above is an example of how to set up the filter on the transmission link, taking the electronic device as the folding machine shown in Figure 9 or the straight-line machine shown in Figure 11 as an example. The following electronic device 01 is taken as an example of a folding machine to illustrate the setting up of the electrical connector 30 in the above transmission link. In some embodiments of the present application, as shown in Figure 19, the electrical connector 30 in the electronic device 01 may be an FPC, and the electrical connector 30 may have a bending area 302 and non-bending areas 301 located on both sides of the bending area 302. Among them, the portion of the electrical connector 30 that passes through the rotating shaft assembly 200 is the above-mentioned bending area 302. The above-mentioned electrical connector 30 may include at least two layers of flexible substrates, and each layer of the flexible substrate may include a flexible dielectric layer and a metal layer stacked with the flexible dielectric layer.

[0117] For example, in the case of an electrical connector 30 comprising three layers of flexible substrates, the two layers of flexible substrates may be, respectively, a first flexible substrate 310, a second flexible substrate 320, and a third flexible substrate 350, as shown in FIG20 (a cross-sectional view taken along dashed line O1-O2 in FIG19 ). Furthermore, to ensure interconnection between the first flexible substrate 310 and the second flexible substrate 320, or between the second flexible substrate 320 and the third flexible substrate 350, and to ensure that the electronic device 01, as a foldable device, can meet dynamic bending reliability requirements exceeding 200,000 cycles during use, the electrical connector 30 may further include a first adhesive layer 330 and a second adhesive layer 360. The first adhesive layer 330 and the second adhesive layer 360 may be located in the non-bending region 301, with the first adhesive layer 330 disposed between the first flexible substrate 310 and the second flexible substrate 320, bonding the first flexible substrate 310 and the second flexible substrate 320 together. The second adhesive layer 360 is disposed between the second flexible substrate 320 and the third flexible substrate 350 to bond the second flexible substrate 320 and the third flexible substrate 350. The present embodiment does not limit the materials of the first adhesive layer 330 and the second adhesive layer 360.

[0118] In this way, because the first adhesive layer 330 and the second adhesive layer 360 are located in the non-bending region 301, and the first adhesive layer 330 and the second adhesive layer 360 are not provided in the bending region 302, there is no adhesion between the first flexible substrate 310 and the second flexible substrate 320, and between the second flexible substrate 320 and the third flexible substrate 350. For example, an air gap 340 may be formed. Therefore, during the bending process of the electrical connector 30, the non-bonded position, such as the air gap 340, can provide a certain deformation space, making it easier for the electrical connector 30 to bend in the bending region 302, thereby achieving the purpose of improving the flexibility of the electrical connector 30.

[0119] The above description is based on an example in which the electrical connector 30 has a three-layer flexible substrate. In other embodiments of the present application, the electrical connector 30 may also have two or more layers of flexible substrates. The configuration of two adjacent layers of flexible substrates is the same as described above and will not be repeated here.

[0120] The following takes the electrical connector 30 including three flexible substrates, such as the first flexible substrate 310 , the second flexible substrate 320 and the third flexible substrate 350 , as an example to illustrate the arrangement of the traces in the bending area 302 and the non-bending area 301 of the flexible substrate.

[0121] In some embodiments of the present application, as shown in FIG21 (a cross-sectional view taken along the dashed line O1-O2 in FIG19 ), any one of the first flexible substrate 310, the second flexible substrate 320, and the third flexible substrate 350 may include a metal layer, such as a copper (Cu) layer, a coverlay (CVL), and a flexible substrate, such as a polyimide (PI) substrate. In other embodiments, the material of the flexible substrate may be at least one of a liquid crystal polymer (LCP) or polytetrafluoroethylene (PTFE).

[0122] This application does not limit this. The film structures of the first flexible substrate 310, the second flexible substrate 320, and the third flexible substrate 350 in the following embodiments are the same as described above and will not be described in detail. Furthermore, in the electrical connector 30, the first flexible substrate 310 can be positioned adjacent to the display screen 100 (as shown in FIG8 ), the second flexible substrate 320 can be stacked on the side of the first flexible substrate 310 facing away from the display screen 100, and the third flexible substrate 350 can be stacked on the side of the second flexible substrate 320 facing away from the display screen 100.

[0123] Furthermore, as shown in Figure 21 , in the electrical connector 30, the signal traces SL in both the bending region 302 and the non-bending region 301 can be disposed in the metal (e.g., Cu) layer of the first flexible substrate 310. The metal (e.g., Cu) layer of the second flexible substrate 320 can serve as a reference ground for the signal traces SL for return signals flowing through the signal traces SL. Furthermore, to reduce insertion loss of signals transmitted by the electrical connector 30, the electrical connector 30 can also include an electromagnetic interference (EMI) shielding layer. For example, the EMI shielding layer can be disposed on the side of the first flexible substrate 310 facing away from the second flexible substrate 320. In this case, the insertion loss of the electrical connector 30 can reach -8dB, as shown in Table 1.

[0124] In other embodiments of the present application, as shown in Figure 22 (a cross-sectional view taken along dashed line O1-O2 in Figure 19 ), the signal traces SL in both the bending region 302 and the non-bending region 301 of the electrical connector 30 can be disposed in the metal (e.g., Cu) layer of the second flexible substrate 320. The EMI layer is located on the side of the first flexible substrate 310 facing away from the second flexible substrate 320, as described above. Consequently, since the signal traces SL are disposed in the metal (e.g., Cu) layer of the second flexible substrate 320, they are located between the metal (e.g., Cu) layer of the first flexible substrate 310 and the metal (e.g., Cu) layer of the third flexible substrate 350. The metal (e.g., Cu) layers of the first flexible substrate 310 and the third flexible substrate 350 can serve as reference grounds for the signal traces SL for return signals flowing through them. In this case, the insertion loss of the electrical connector 30 can be -4.8 dB, as shown in Table 1.

[0125] In other embodiments of the present application, as shown in Figure 23 (a cross-sectional view taken along dashed line O1-O2 in Figure 19 ), in the electrical connector 30, the signal traces SL in both the bending region 302 and the non-bending region 301 can be disposed in the metal (e.g., Cu) layer of the second flexible substrate 320. In the bending region 302, an EMI layer is disposed between the first flexible substrate 310 and the second flexible substrate 320, and between the second flexible substrate 320 and the third flexible substrate 350. In the non-bending region, the EMI layer is located on the side of the first flexible substrate 310 facing away from the second flexible substrate 320. In this case, the insertion loss of the electrical connector 30 can be -6.3 dB, as shown in Table 1.

[0126] In yet other embodiments of the present application, as shown in Figure 24 (a cross-sectional view taken along dashed line O1-O2 in Figure 19 ), in the electrical connector 30, the signal traces SL in both the bending region 302 and the non-bending region 301 can be disposed in the metal (e.g., Cu) layer of the second flexible substrate 320. An EMI layer is disposed between the first flexible substrate 310 and the second flexible substrate 320 in the bending region 302. In the non-bending region, the EMI layer is located on the side of the first flexible substrate 310 facing away from the second flexible substrate 320. In this case, the insertion loss of the electrical connector 30 can be -6.3 dB, as shown in Table 1.

[0127] Table 1

[0128] As can be seen from the above, when the electrical connector 30 is an FPC, in order to ensure the FPC has good flexibility and meet the dynamic bending reliability requirement of more than 200,000 times, the electrical connector 30 has the aforementioned air gap 340 between two adjacent flexible substrates within the bending region 302. However, during the bending process of the electronic device 01, as shown in Figure 25, due to the air gap 340 between the two adjacent flexible substrates (indicated by black lines in Figure 25) within the bending region 302 of the electrical connector 30, the two adjacent flexible substrates that are bent and deformed in the bending region 302 will separate from each other. As a result, the spacing between the signal trace SL provided in one layer of the flexible substrate in the electrical connector 30 and the reference ground provided in the other layer of the flexible substrate will change, resulting in a significant change in the impedance of the electrical connector 30 and a significant fluctuation in the impedance of the entire transmission link.

[0129] For example, the impedance fluctuation of the electrical connector 30 shown in Figure 21 can be 11ohm as in Table 1, the impedance fluctuation of the electrical connector 30 shown in Figure 22 can be 50ohm as in Table 1, the impedance fluctuation of the electrical connector 30 shown in Figure 23 can be 33ohm as in Table 1, and the impedance fluctuation of the electrical connector 30 shown in Figure 23 can be 17.5ohm as in Table 1.

[0130] Based on this, in some embodiments of the present application, when the above-mentioned electronic device 01 is a low-power device such as a mobile phone or a tablet computer, and the electronic device 01 is capable of 5G communication, the components in the electronic device 01, such as the RFIC4201 shown in Figure 18, can adopt a low-power high-speed communication interface. For example, the transmission rate of the low-power high-speed communication interface can be greater than 5Gbps / lane to meet the requirements of 5G communication. In addition, in the working state (burst state), the power consumption of the port physical layer (physical, PHY) of the low-power high-speed communication interface can be less than 50mW / lane to meet the low power consumption requirements of the electronic device 01. However, the driving balancing capability of the PHY of the low-power high-speed communication interface is weak. When the impedance of the above-mentioned transmission link fluctuates greatly, the risk of transmitting high-speed signals in the above-mentioned transmission link will increase.

[0131] To address the aforementioned impedance variation issue, in some embodiments of the present application, as shown in FIG26 (a cross-sectional view taken along the dashed line O1-O2 in FIG19 ), the electrical connector 30 may include a first flexible substrate 310, a second flexible substrate 320, and a third flexible substrate 350. The first flexible substrate 310 may include a first signal trace SL1 disposed in the bending region 302. The second flexible substrate 320 may include a second signal trace SL2 disposed in the non-bending region 301. The second signal trace SL2 is electrically connected to the first signal trace SL1.

[0132] In this case, within the bend region 302 of the electrical connector 30, the first signal trace SL1 is disposed within the first flexible substrate 310 near the display screen 100. The reference ground for the first signal trace SL1 can be the metal (e.g., Cu) layer of the second flexible substrate 320. The metal (e.g., Cu) layer of the second flexible substrate 320 is located on one side of the first signal trace SL1. When the bend region 302 of the electrical connector 30 bends, only the distance between the first signal trace SL1 and the reference ground below it changes dynamically, resulting in minimal impedance fluctuations, such as 11 ohms as shown in Table 2. In contrast, in the embodiment shown in FIG22 , where reference grounds are disposed above and below the signal trace SL within the bend region 302, the distance between the reference grounds above and below the signal trace SL changes when the bend region 302 of the electrical connector 30 bends, resulting in significant impedance fluctuations (e.g., 50 ohms as shown in Table 1).

[0133] On this basis, in the non-bending region 301 of the electrical connector 30, the second signal trace SL2 is disposed in the middle of the second flexible substrate 320. Therefore, the metal (e.g., Cu) layer of the first flexible substrate 310 above the second signal trace SL2 and the metal (e.g., Cu) layer of the third flexible substrate 350 below the second signal trace SL2 can both serve as a reference ground for the second signal trace SL2. This reference ground is used for the return signal flowing through the second signal trace SL2, thereby reducing insertion loss. For example, the insertion loss of the electrical connector 30 shown in Figure 26 can reach -6.3dB as shown in Table 2.

[0134] Continuing with FIG26 , the third flexible substrate 350 is stacked on the side of the second flexible substrate 320 facing away from the first flexible substrate 310. Furthermore, in the bending region 302, the first flexible substrate 310 and the second flexible substrate 320 are not bonded together, for example, with a first air gap 3401. The third flexible substrate 350 and the second flexible substrate 320 are not bonded together, for example, with a second air gap 3402. The technical effects of the first air gap 3401 and the second air gap 3402 are similar to those of the air gap 340 described above and will not be further elaborated here. Furthermore, an EMI layer is stacked on the side of the first flexible substrate 310 facing the display screen, i.e., the side facing away from the second flexible substrate 320. The technical effects of this EMI layer are similar to those described above and will not be further elaborated here.

[0135] Alternatively, in other embodiments of the present application, as shown in FIG27 (a cross-sectional view taken along the dotted line O1-O2 in FIG19 ), the electrical connector 30 may include a first flexible substrate 310, a second flexible substrate 320, and a third flexible substrate 350. The arrangement and technical effects of the signal traces in the first flexible substrate 310 and the second flexible substrate 320, such as the first signal trace SL1 and the second signal trace SL2, are the same as those in the solution shown in FIG26 and are not further described herein.

[0136] The difference is that, as shown in Figure 27 , the second flexible substrate 320 also includes a first cover film CVL1 and a first flexible substrate 3201. The material of the first flexible substrate 3201 can be at least one of the aforementioned PI, LCP, or PTFE. The first flexible substrate 3201 and the first cover film CVL1 are stacked, and the second signal trace SL2 is disposed between the first cover film CVL1 and the first flexible substrate 3201. Furthermore, in the bend region, the first cover film CVL1 and the first flexible substrate 3201 may be non-adhesive, for example, with a third air gap 3403 formed therebetween.

[0137] In this case, in the bending region 302 of the electrical connector 30, the first signal trace SL1 is disposed within the first flexible substrate 310 near the display screen 100. Furthermore, the first cover film CVL1 and the first flexible substrate 3201 are not bonded, for example, with the aforementioned third air gap 3403. This results in the second flexible substrate 320 having no metal (e.g., Cu) layer within the bending region 302. Therefore, the reference ground for the first signal trace SL1 can be the metal (e.g., Cu) layer of the third flexible substrate 350. Consequently, when the bending region 302 of the electrical connector 30 bends, the metal (e.g., Cu) layer of the third flexible substrate 350 is located on one side of the first signal trace SL1. Furthermore, the distance between the first signal trace SL1 and the metal (e.g., Cu) layer of the third flexible substrate 350 is relatively large. Therefore, dynamic changes in the distance between the first signal trace SL1 and the metal (e.g., Cu) layer of the third flexible substrate 350 have a minimal impact on the impedance fluctuation of the electrical connector 30. For example, the impedance fluctuation can be 4 ohms, as shown in Table 2.

[0138] In addition, similarly, in the non-bending area 301 of the electrical connector 30 , the second signal trace SL2 is disposed in the middle of the second flexible substrate 320 . Therefore, the insertion loss of the electrical connector 30 shown in FIG. 27 can reach −6.3 dB in Table 2.

[0139] Table 2

[0140] The above is only a specific embodiment of the present application, but the scope of protection of this application is not limited to this. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A circuit board assembly, characterized in that, Comprising: A first circuit board; A system-on-chip (SoC) circuit disposed on the first circuit board, and the SoC circuit is electrically connected to the first circuit board; A second circuit board spaced apart from the first circuit board; A radio frequency (RF) circuit disposed on the second circuit board, and the RF circuit is electrically connected to the second circuit board; An electrical connector, one end of the electrical connector is electrically connected to the first circuit board, and the other end of the electrical connector is electrically connected to the second circuit board; the SoC circuit is electrically connected to the RF circuit through the electrical connector.

2. The circuit board assembly according to claim 1, wherein The RF circuit includes: an RF chip and an RF antenna electrically connected to the RF chip; The SoC circuit includes: an SoC chip and a clock chip electrically connected to the SoC chip; the SoC chip and the clock chip are electrically connected to the RF chip through the electrical connector; The circuit board assembly further includes: A first low-pass filter circuit electrically connected between the clock chip and the electrical connector; the cut-off frequency of the first low-pass filter circuit is the starting frequency f11 of the operating frequency band of the RF antenna.

3. The circuit board assembly according to claim 1 or 2, wherein The RF circuit includes: an RF chip and an RF antenna electrically connected to the RF chip; the RF chip is electrically connected to the SoC circuit through the electrical connector; The circuit board assembly further includes: A second low-pass filter circuit electrically connected between the RF chip and the electrical connector; the cut-off frequency of the second low-pass filter circuit is the starting frequency f11 of the operating frequency band of the RF antenna.

4. The circuit board assembly according to claim 3, wherein The circuit board assembly further includes: A wireless charging coil; A high-pass filter circuit electrically connected between the RF chip and the electrical connector; the cut-off frequency of the high-pass filter circuit is the ending frequency f22 of the operating frequency band of the wireless charging coil; Wherein, the high-pass filter circuit and the second low-pass filter circuit are connected in series to form a band-pass filter circuit, and the band-pass frequency band of the band-pass filter circuit is f22~f11.

5. An electronic device, characterized in that, The electronic device includes: A display screen; The circuit board assembly according to any one of claims 1-4, and the circuit board assembly is electrically connected to the display screen.

6. The electronic device according to claim 5, wherein The electronic device further includes: A first middle frame disposed on the back of the display screen, and the first circuit board in the circuit board assembly is disposed on the first middle frame; A second middle frame disposed on the back of the display screen, and the second circuit board in the circuit board assembly is disposed on the second middle frame; A rotating shaft assembly disposed on the back of the display screen and between the first middle frame and the second middle frame, and the rotating shaft assembly is connected to the first middle frame and the second middle frame so that the first middle frame is rotatably connected to the second middle frame through the rotating shaft assembly; Wherein, the electrical connector in the circuit board assembly is disposed on the side of the first middle frame and the second middle frame away from the display screen, and a part of the electrical connector passes through the rotating shaft assembly.

7. The electronic device according to claim 6, wherein the electrical connector is a flexible printed circuit board (FPC), the FPC has a bending area and non-bending areas on both sides of the bending area; the part of the electrical connector passing through the rotating shaft assembly is located in the bending area; the FPC includes: a first flexible substrate including a first signal trace provided in the bending area; a second flexible substrate laminated on a side of the first flexible substrate facing away from the display screen; the second flexible substrate includes a second signal trace provided in the non-bending area, and the second signal trace is electrically connected to the first signal trace; a first adhesive layer located in the non-bending area and provided between the first flexible substrate and the second flexible substrate to bond the first flexible substrate and the second flexible substrate; wherein, in the bending area, the first flexible substrate and the second flexible substrate are not adhered to each other; a third flexible substrate laminated on a side of the second flexible substrate facing away from the first flexible substrate; a second adhesive layer located in the non-bending area and provided between the second flexible substrate and the third flexible substrate to bond the second flexible substrate and the third flexible substrate; wherein, in the bending area, the third flexible substrate and the second flexible substrate are not adhered to each other.

8. The electronic device according to claim 7, wherein the second flexible substrate further includes: a first cover film; a first flexible substrate laminated with the first cover film, and the second signal trace is provided between the first cover film and the first flexible substrate; wherein, in the bending area, the first cover film and the first flexible substrate are not adhered to each other.

9. The electronic device according to claim 7 or 8, wherein the FPC further includes an electromagnetic shielding layer laminated on a side of the first flexible substrate facing the display screen.

10. The electronic device according to any one of claims 6-9, characterized in that, The electronic device further includes: a first battery provided on a side of the first middle frame facing away from the display screen, and a vertical projection of the first battery on the first middle frame does not overlap with a vertical projection of the first circuit board on the first middle frame; a second battery provided on a side of the second middle frame facing away from the display screen; when the display screen is in a flattened state, the second circuit board is located on a side of the second battery facing away from the first battery and the first circuit board.

11. The electronic device according to claim 5, characterized in that, The electronic device further includes at least one camera provided between the first circuit board and the second circuit board.

12. The electronic device according to any one of claims 5-11, characterized in that, The electrical connector is a flexible printed circuit board, and the thickness of the electrical connector is less than or equal to 0.2 mm.

13. The electronic device according to claim 5 or 6, or 11, characterized in that, The electrical connector is a coaxial cable, and the diameter of the coaxial cable is less than or equal to 0.2 mm.

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