Patent Publication Number: US-2022232704-A1

Title: Foldable electronic device including flexible printed circuit board

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a Continuation of U.S. patent application Ser. No. 16/789,666 filed on Feb. 13, 2020 which is based on and claims priority under 35 U.S.C. 119 to Korean Patent Application No. 10-2019-0019515, filed on Feb. 19, 2019, in the Korean Intellectual Property Office, the disclosure of which is herein incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     One or more embodiments disclosed herein generally relate to a foldable electronic device including a flexible printed circuit board. 
     BACKGROUND 
     The electronic device related to the instant application may be a device that performs specific functions in accordance with programs installed therein, such as home appliances, electronic notepads, mobile multimedia players, mobile communication terminals, tablet PCs, video/sound devices, desktop/laptop computers, automobile navigation systems, etc. For example, these electronic devices can output information stored therein as sound or images. As development of these electronic devices have advanced and high-speed and large-capacity wireless communication networks have been popularized recently, an increasing number of functions can be integrated in a single electronic device such as a mobile communication terminal. These functions may include communication, entertainment such as gaming, multimedia such as playback of music/video, communication and security for mobile banking, calendar, electronic wallet, etc. These electronic devices are also increasingly miniaturized so that users can conveniently carry them. 
     As the above functions of the electronic devices have increased, users can not only make voice calls or write short text messages, but also use multimedia services of the electronic devices. In order to provide users with convenience when using the multimedia services, the electronic devices are being equipped with wider display panels. Further, recently, foldable electronic devices equipped with flexible display devices are being implemented. 
     SUMMARY 
     A foldable electronic device according to an embodiment includes one display panel and may include two housings surrounding the display panel with the folding region of the display panel therebetween. The electronic device may include various electronic devices for performing various functions and operations such as communication, entertainment, multimedia, and security. These electronic parts may be separately disposed in the two housings subject to various design considerations, such as spatial mounting within the electronic devices. 
     The electronic parts are mounted on a PCB (Printed Circuit Board) included in the housing and may be electrically connected to one another through at least one FPCB (Flexible Printed Circuit Board). For example, the FPCB may be a C2C (connector to connector) FPCB connecting connectors respectively formed on two different substrates to each other. 
     Various signal lines may be disposed on the FPCB, such as signal lines for implementing various functions including high-quality displaying, operating a high-performance camera and/or stereo speakers, or power supply. According to a certain embodiment, when the FPCB is connected to two substrates disposed in different housings, some signal lines disposed on the FPCB that are sensitive to impedance may be subject to a greater possibility of signal loss. 
     A foldable electronic device according to an embodiment may include: a hinge structure having a folding axis and a foldable housing which includes a folding section where the electronic device is folded about the folding axis, a first housing structure, and a second housing structure. The first housing structure may be connected to the hinge structure, and may include a first surface facing a first direction, a second surface facing a second direction opposite to the first direction, and a first printed circuit board having a first plurality of electronic components mounted thereon. The second housing structure may be connected to the hinge structure, and may include a third surface facing a third direction, a fourth surface facing a fourth direction opposite to the third direction, and a second printed circuit board having a second plurality of electronic components mounted thereon. The second housing structure may be configured to be foldable on the first housing structure around the hinge structure. The first surface may face the third surface when the electronic device is folded and the third direction may coincide with the first direction when the electronic device is unfolded. The device may further include a flexible display disposed in the foldable housing and extending from the first surface of the first housing structure to the third surface of the second housing structure, a first flexible printed circuit board configured to cross at least a portion of the hinge structure and configured to electrically connect the first printed circuit board and the second printed circuit board through first connection terminals at both ends thereof, and a second flexible printed circuit board configured to cross at least a portion of the hinge structure and configured to electrically connect the first printed circuit board and the second printed circuit board through second connection terminals at both ends thereof. The first signal lines having a first signal characteristic may be disposed on the first flexible printed circuit board and second signal lines having a second signal characteristic may be disposed on the second flexible printed circuit board. 
     An electronic device according to an embodiment may include: a housing: a first printed circuit board disposed in the housing; a second printed circuit board disposed in the housing and spaced apart from the first printed circuit board; a first flexible printed circuit board electrically connecting the first printed circuit board and the second printed circuit board; and a second flexible printed circuit board electrically connecting the first printed circuit board and the second printed circuit board, in which the second flexible printed circuit board may be longer than the first flexible printed circuit board. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of the disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a block diagram of an electronic device in a network environment according to various embodiments; 
         FIG. 2  is plan views illustrating an electronic device in an unfolded state according to an embodiment; 
         FIG. 3  is plan views illustrating an electronic device in a folded state according to an embodiment; 
         FIG. 4  is an exploded perspective view of the electronic device according to an embodiment; 
         FIG. 5A  is a perspective view showing an example of an unfolded electronic device  101  according to an embodiment; 
         FIG. 5B  is a perspective view showing an example of a partially folded electronic device  101  according to an embodiment; 
         FIG. 6  is a plan view showing spatial relationships of components in the electronic device when unfolded, according to an embodiments; 
         FIG. 7A  is a perspective view of a flexible printed circuit board (e.g., a first flexible printed circuit board) according to an embodiment; 
         FIG. 7B  is a front view of the flexible printed circuit board (e.g., the first flexible printed circuit board) according to an embodiment; 
         FIG. 7C  is a rear view of the flexible printed circuit board (e.g., the first flexible printed circuit board) according to an embodiment; 
         FIG. 8  is a plan view showing when the first flexible printed circuit board is mounted on a hinge portion of the electronic device according to an embodiment; 
         FIG. 9  is a side view showing a cross-section taken along line B-B′ of the foldable electronic device according to the embodiments shown in  FIG. 8 ; 
         FIG. 10  is a view showing a first flexible printed circuit board and a second flexible printed circuit board according to an embodiment; 
         FIG. 11  is schematic diagrams showing circuits disposed on each layer when the first flexible printed circuit board according to an embodiment includes a plurality of layers; 
         FIG. 12  is schematic diagrams showing circuits disposed on each layer when the second flexible printed circuit board according to an embodiment includes a plurality of layers; 
         FIG. 13A  is a schematic diagram showing a layer having a plurality of pins when a flexible printed circuit board (e.g., the first flexible printed circuit board) according to an embodiment includes a plurality of layers; 
         FIG. 13B  is a schematic diagram showing a layer having a signal line that can perform high-speed communication when a flexible printed circuit board (e.g., the first flexible printed circuit board) according to an embodiment includes a plurality of layers; 
         FIG. 14A  is a schematic diagram showing layers having a plurality of pins when a flexible printed circuit board (e.g., the first flexible printed circuit board) according to an embodiment includes a plurality of layers; and 
         FIG. 14B  is a schematic diagram showing layers having a signal line that can perform high-speed communication when a flexible printed circuit board (e.g., the first flexible printed circuit board) according to an embodiment includes a plurality of layers. 
     
    
    
     DETAILED DESCRIPTION 
     According to certain embodiments, it is possible to provide a foldable electronic device that includes at least two flexible printed circuit boards connecting two substrates respectively included in two different housings, and includes a plurality of signal lines separately disposed on the at least two flexible printed circuit boards for improved signal characteristics. 
     According to certain embodiments, since a plurality of signal lines are separately disposed on at least the two flexible printed circuit boards for improved signal characteristics, it is possible to implement a design that minimizes impedance influence. 
     The placement of the plurality of signal lines is done in consideration of the various characteristics (e.g., sensitivity) of the signal lines. Thus it is possible to prevent deterioration of the performance of the electronic device. 
     According to an embodiment, since there is provided a wiring method that gives approximately the same lengths to different signal lines formed on a layer, it is possible to prevent timing skew or delay and there is no need for an additional wiring to reduce timing skew or delay when designing the signal lines. 
       FIG. 1  is a block diagram illustrating an electronic device  101  in a network environment  100  according to various embodiments. 
     Referring to  FIG. 1 , the electronic device  101  in the network environment  100  may communicate with an electronic device  102  via a first network  198  (e.g., a short-range wireless communication network), or an electronic device  104  or a server  108  via a second network  199  (e.g., a long-range wireless communication network). According to an embodiment, the electronic device  101  may communicate with the electronic device  104  via the server  108 . According to an embodiment, the electronic device  101  may include a processor  120 , memory  130 , an input device  150 , a sound output device  155 , a display device  160 , an audio module  170 , a sensor module  176 , an interface  177 , a haptic module  179 , a camera module  180 , a power management module  188 , a battery  189 , a communication module  190 , a subscriber identification module (SIM)  196 , or an antenna module  197 . In some embodiments, at least one (e.g., the display device  160  or the camera module  180 ) of the components may be omitted from the electronic device  101 , or one or more other components may be added in the electronic device  101 . In some embodiments, some of the components may be implemented as single integrated circuitry. For example, the sensor module  176  (e.g., a fingerprint sensor, an iris sensor, or an illuminance sensor) may be implemented as embedded in the display device  160  (e.g., a display). 
     The processor  120  may execute, for example, software (e.g., a program  140 ) to control at least one other component (e.g., a hardware or software component) of the electronic device  101  coupled with the processor  120 , and may perform various data processing or computation. According to one embodiment, as at least part of the data processing or computation, the processor  120  may load a command or data received from another component (e.g., the sensor module  176  or the communication module  190 ) in volatile memory  132 , process the command or the data stored in the volatile memory  132 , and store resulting data in non-volatile memory  134 . According to an embodiment, the processor  120  may include a main processor  121  (e.g., a central processing unit (CPU) or an application processor (AP)), and an auxiliary processor  123  (e.g., a graphics processing unit (GPU), an image signal processor (ISP), a sensor hub processor, or a communication processor (CP)) that is operable independently from, or in conjunction with, the main processor  121 . Additionally or alternatively, the auxiliary processor  123  may be adapted to consume less power than the main processor  121 , or to be specific to a specified function. The auxiliary processor  123  may be implemented as separate from, or as part of the main processor  121 . 
     The auxiliary processor  123  may control at least some of functions or states related to at least one component (e.g., the display device  160 , the sensor module  176 , or the communication module  190 ) among the components of the electronic device  101 , instead of the main processor  121  while the main processor  121  is in an inactive (e.g., sleep) state, or together with the main processor  121  while the main processor  121  is in an active state (e.g., executing an application). According to an embodiment, the auxiliary processor  123  (e.g., an image signal processor or a communication processor) may be implemented as part of another component (e.g., the camera module  180  or the communication module  190 ) functionally related to the auxiliary processor  123 . 
     The memory  130  may store various data used by at least one component (e.g., the processor  120  or the sensor module  176 ) of the electronic device  101 . The various data may include, for example, software (e.g., the program  140 ) and input data or output data for a command related thereto. The memory  130  may include the volatile memory  132  or the non-volatile memory  134 . 
     The program  140  may be stored in the memory  130  as software, and may include, for example, an operating system (OS)  142 , middleware  144 , or an application  146 . 
     The input device  150  may receive a command or data to be used by other component (e.g., the processor  120 ) of the electronic device  101 , from the outside (e.g., a user) of the electronic device  101 . The input device  150  may include, for example, a microphone, a mouse, a keyboard, or a digital pen (e.g., a stylus pen). 
     The sound output device  155  may output sound signals to the outside of the electronic device  101 . The sound output device  155  may include, for example, a speaker or a receiver. The speaker may be used for general purposes, such as playing multimedia or playing recordings, and the receiver may be used for an incoming calls. According to an embodiment, the receiver may be implemented as separate from, or as part of the speaker. 
     The display device  160  may visually provide information to the outside (e.g., a user) of the electronic device  101 . The display device  160  may include, for example, a display, a hologram device, or a projector and control circuitry to control a corresponding one of the display, hologram device, and projector. According to an embodiment, the display device  160  may include touch circuitry adapted to detect a touch, or sensor circuitry (e.g., a pressure sensor) adapted to measure the intensity of force incurred by the touch. 
     The audio module  170  may convert a sound into an electrical signal and vice versa. According to an embodiment, the audio module  170  may obtain the sound via the input device  150 , or output the sound via the sound output device  155  or a headphone of an external electronic device (e.g., an electronic device  102 ) directly (e.g., wiredly) or wirelessly coupled with the electronic device  101 . 
     The sensor module  176  may detect an operational state (e.g., power or temperature) of the electronic device  101  or an environmental state (e.g., a state of a user) external to the electronic device  101 , and then generate an electrical signal or data value corresponding to the detected state. According to an embodiment, the sensor module  176  may include, for example, a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor. 
     The interface  177  may support one or more specified protocols to be used for the electronic device  101  to be coupled with the external electronic device (e.g., the electronic device  102 ) directly (e.g., wiredly) or wirelessly. According to an embodiment, the interface  177  may include, for example, a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, or an audio interface. 
     A connecting terminal  178  may include a connector via which the electronic device  101  may be physically connected with the external electronic device (e.g., the electronic device  102 ). According to an embodiment, the connecting terminal  178  may include, for example, a HDMI connector, a USB connector, a SD card connector, or an audio connector (e.g., a headphone connector). 
     The haptic module  179  may convert an electrical signal into a mechanical stimulus (e.g., a vibration or a movement) or electrical stimulus which may be recognized by a user via his or her tactile sensation or kinesthetic sensation. According to an embodiment, the haptic module  179  may include, for example, a motor, a piezoelectric element, or an electric stimulator. 
     The camera module  180  may capture a still image or moving images. According to an embodiment, the camera module  180  may include one or more lenses, image sensors, image signal processors, or flashes. 
     The power management module  188  may manage power supplied to the electronic device  101 . According to one embodiment, the power management module  188  may be implemented as at least part of, for example, a power management integrated circuit (PMIC). 
     The battery  189  may supply power to at least one component of the electronic device  101 . According to an embodiment, the battery  189  may include, for example, a primary cell which is not rechargeable, a secondary cell which is rechargeable, or a fuel cell. 
     The communication module  190  may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device  101  and the external electronic device (e.g., the electronic device  102 , the electronic device  104 , or the server  108 ) and performing communication via the established communication channel. The communication module  190  may include one or more communication processors that are operable independently from the processor  120  (e.g., the application processor (AP)) and supports a direct (e.g., wired) communication or a wireless communication. According to an embodiment, the communication module  190  may include a wireless communication module  192  (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module  194  (e.g., a local area network (LAN) communication module or a power line communication (PLC) module). A corresponding one of these communication modules may communicate with the external electronic device via the first network  198  (e.g., a short-range communication network, such as Bluetooth™, wireless-fidelity (Wi-Fi) direct, or infrared data association (IrDA)) or the second network  199  (e.g., a long-range communication network, such as a cellular network, the Internet, or a computer network (e.g., LAN or wide area network (WAN)). These various types of communication modules may be implemented as a single component (e.g., a single chip), or may be implemented as multi components (e.g., multi chips) separate from each other. The wireless communication module  192  may identify and authenticate the electronic device  101  in a communication network, such as the first network  198  or the second network  199 , using subscriber information (e.g., international mobile subscriber identity (IMSI)) stored in the subscriber identification module  196 . 
     The antenna module  197  may transmit or receive a signal or power to or from the outside (e.g., the external electronic device) of the electronic device  101 . According to an embodiment, the antenna module  197  may include an antenna including a radiating element composed of a conductive material or a conductive pattern formed in or on a substrate (e.g., PCB). According to an embodiment, the antenna module  197  may include a plurality of antennas. In such a case, at least one antenna appropriate for a communication scheme used in the communication network, such as the first network  198  or the second network  199 , may be selected, for example, by the communication module  190  (e.g., the wireless communication module  192 ) from the plurality of antennas. The signal or the power may then be transmitted or received between the communication module  190  and the external electronic device via the selected at least one antenna. According to an embodiment, another component (e.g., a radio frequency integrated circuit (RFIC)) other than the radiating element may be additionally formed as part of the antenna module  197 . 
     At least some of the above-described components may be coupled mutually and communicate signals (e.g., commands or data) therebetween via an inter-peripheral communication scheme (e.g., a bus, general purpose input and output (GPIO), serial peripheral interface (SPI), or mobile industry processor interface (MIPI)). 
     According to an embodiment, commands or data may be transmitted or received between the electronic device  101  and the external electronic device  104  via the server  108  coupled with the second network  199 . Each of the electronic devices  102  and  104  may be a device of a same type as, or a different type, from the electronic device  101 . According to an embodiment, all or some of operations to be executed at the electronic device  101  may be executed at one or more of the external electronic devices  102 ,  104 , or  108 . For example, if the electronic device  101  should perform a function or a service automatically, or in response to a request from a user or another device, the electronic device  101 , instead of, or in addition to, executing the function or the service, may request the one or more external electronic devices to perform at least part of the function or the service. The one or more external electronic devices receiving the request may perform the at least part of the function or the service requested, or an additional function or an additional service related to the request, and transfer an outcome of the performing to the electronic device  101 . The electronic device  101  may provide the outcome, with or without further processing of the outcome, as at least part of a reply to the request. To that end, a cloud computing, distributed computing, or client-server computing technology may be used, for example. 
       FIG. 2  is plan views illustrating an electronic device in an unfolded state according to an embodiment.  FIG. 3  is plan views illustrating an electronic device in a folded state according to an embodiment. 
     Referring to  FIGS. 2 and 3 , in an embodiment, an electronic device  101  may include: a foldable housing  300 ; a hinge cover (e.g., a hinge cover  330  in  FIG. 3 ) covering a foldable portion of the foldable housing  300 ; and a flexible or foldable display  200  (or “display  200 ” for short) (e.g., the display device  160  in  FIG. 1 ) disposed in a space defined by the foldable housing  300 . According to an embodiment, the surface in which the display  200  is disposed may be referred to as the front surface of the electronic device  101 . The opposite surface of the front surface may be referred to as the rear surface of the electronic device  101 . The surface surrounding the space between the front surface and the rear surface may be referred to as the side of the electronic device  101 . 
     According to an embodiment, the foldable housing  300  may include a first housing structure  310 , a second housing structure  320  having a sensor section  324 , a first rear cover  380 , a second rear cover  390 , and a hinge structure (a hinge structure  510  in  FIG. 4 ). The foldable housing  300  of the electronic device  101  is not limited to the type and combination shown in  FIGS. 2 and 3 , and may be implemented using other shapes or components. For example, in another embodiment, the first housing structure  310  and the first rear cover  380  may be integrally formed, and the second housing structure  320  and the second rear cover  390  may be integrally formed. 
     According to an embodiment, the first housing structure  310  is connected to a hinge structure (e.g., the hinge structure  550  in  FIG. 4 ) and may have a first surface facing a first direction and a second surface facing a second direction opposite to the first direction. The second housing structure  320  is connected to the hinge structure  510 , has a third surface facing a third direction and a fourth surface facing a fourth direction opposite to the third direction, and can rotate about the hinge structure  510  (or, a hinge shaft) with respect to the first housing structure  310 . Accordingly, the electronic device  101  can be folded or unfolded. In the electronic device  101 , the first surface may face the third surface while folded, and the third direction may be the same as the first direction while unfolded. 
     According to an embodiment, the first housing structure  310  and the second housing structure  320  are disposed at both sides with a folding axis (axis A) therebetween, and the entire shape is symmetric with respect to the folding axis A. As described below, the first housing structure  310  and the second housing structure  320  may be changed in angle or distance therebetween in accordance with whether the electronic device  101  is unfolded or folded or in an intermediate partially unfolding. According to an embodiment, the second housing structure  320 , unlike the first housing structure  310 , additionally has a sensor section  324  in which various sensors are disposed, but they may be symmetrical in other areas. 
     According to an embodiment, as shown in  FIG. 2 , the first housing structure  310  and the second housing structure  320  may form a recess together for accommodating the display  200 . According to an embodiment, the recess may have two or more different widths in a direction perpendicular to the folding axis A due to the sensor section  324 . 
     According to an embodiment, the recess may have a first width w 1  between a first portion  310   a  that is parallel with the folding axis A in the first housing structure  310  and a first portion  320   a  formed at the edge of the sensor section of the second housing structure  320 . The recess may have a second width w 2  defined by a second area  310   b  of the first housing structure  310  and a second portion  320   b  that is not the sensor section  324  and is parallel with the folding axis A in the second housing structure  320 . In this case, the second width w 2  may be larger than the first width w 1 . Thus, the first portion  310   a  of the first housing structure  310  and the first portion  320   a  of the second housing structure  320 , which are asymmetric to each other, may define the first width w 1  of the recess, and the second portion  310   b  of the first housing structure  310  and the second portion  320   b  of the second housing structure  320 , which are symmetric to each other, may define the second width w 2  of the recess. According to an embodiment, the first portion  320   a  and the second portion  320   b  of the second housing structure  320  may have different distances from the folding axis A. The widths of the recess are not limited to the example shown in the figures. In another embodiment, the recess may have a plurality of widths due to the shape of the sensor section  324  or the asymmetric shapes of the first housing  310  and the second housing  320 . 
     According to an embodiment, at least a portion of the first housing structure  310  and the second housing structure  320  may be made of a metallic material or a nonmetallic material that has rigidity of a selected intensity to support the display  200 . At least a portion made of the metallic material can provide a ground plane of the electronic device  101  and may be electrically connected with a ground line formed on a printed circuit board (e.g., a printed circuit board  520  shown in  FIG. 4 ). 
     According to an embodiment, the sensor section  324  may be defined to have a predetermined area adjacent to a corner of the second housing structure  320 . However, the disposition, shape, and size of the sensor section  324  are not limited to the example shown in the figures. For example, in another embodiment, the sensor section  324  may be provided at another corner of the second housing structure  320  or in a predetermined area between an upper corner and a lower corner. In an embodiment, components for performing various functions of the electronic device  101  may be exposed on the front surface of the electronic device through the sensor section  324  or one or more openings provided in the sensor section  324 . In various embodiments, the components may include various kinds of sensors, such as a front camera, a receiver, a proximity sensor, etc. 
     According to an embodiment, the first rear cover  380  is disposed at one side from the folding axis on the rear surface of the electronic device  101  and, for example, may have a substantially rectangular shape, and whose periphery may be surrounded by the first housing structure  310 . Similarly, the second rear cover  390  is disposed at the other side from the folding axis on the rear surface of the electronic device  101  and the periphery thereof may be surrounded by the second housing structure  320 . 
     According to an embodiment, the first rear cover  380  and the second rear cover  390  may be substantially symmetrical to each other with respect to the folding axis (axis A) therebetween. However, the first rear cover  380  and the second rear cover  390  are not necessarily symmetrical, and in another embodiment, the electronic device  101  may include a first rear cover  380  and a second rear cover  390  that have asymmetric shapes. In another embodiment, first rear cover  380  may be formed integrally with the first housing structure  310 , and the second rear cover  390  may be may be formed integrally with the second housing structure  320 . 
     According to an embodiment, the first rear cover  380 , the second rear cover  390 , the first housing structure  310 , and the second housing structure  320  may define a space in which various components (e.g., a printed circuit board or a battery) of the electronic device  101  can be disposed. According to an embodiment, one or more components may be disposed or visually exposed on the rear surface of the electronic device  101 . For example, at least a portion of a sub-display may be visually exposed through the first rear surface section  382  of the first rear cover  380 . In another embodiment, one or more components or sensors may be visually exposed through a second rear surface section  392  of the second rear cover  390 . In one embodiment, the sensors may include a proximity sensor and/or a rear camera. 
     According to an embodiment, the front camera exposed on the front surface of the electronic device  101  through one or more openings in the sensor section  324  or the rear camera exposed through the second rear surface section  392  of the second rear cover  390  may include one or a plurality of lenses, an image sensor, and/or an image signal processor. A flash, for example, may include a light emitting diode or a xenon lamp. In an embodiment, two or more lenses, including an infrared camera, a wide-angle lens, and a telephoto lens, and image sensors may be disposed on one surface of the electronic device  101 . 
     Referring to  FIG. 3 , the hinge cover  330  is disposed between the first housing structure  310  and the second housing structure  320  and may be configured to cover internal components (e.g., a hinge structure  510  in  FIG. 4 ). According to an embodiment, the hinge cover  330  may be covered by a portion of the first housing structure  310  and the second housing structure  320  or may be exposed to the outside, depending whether the electronic device  101  is folded, unfolded, or partially unfolded. 
     According to an embodiment, as shown in  FIG. 2 , when the electronic device  101  is unfolded, the hinge cover  330  can be covered by the first housing structure  310  and the second housing structure  320 . As another example, as shown in  FIG. 3 , when the electronic device  101  is fully folded, the hinge cover  330  can be exposed between the first housing structure  310  and the second housing structure  320 . As another example, in the intermediate state of partially unfolded in which first housing structure  310  and the second housing structure  320  are folded with a certain angle between 0 and 180 degrees, the hinge cover  330  can be partially exposed between the first housing structure  310  and the second housing structure  320 . However, in this case, the exposed area may be smaller than when the device is fully folded. In an embodiment, the hinge cover  330  may have a curved surface. 
     According to an embodiment, the display  200  may be disposed in a space defined by the foldable housing  300 . For example, the display  200  may be seated in the recess formed by the foldable housing  320  and may constitute substantially the entirety of the front surface of the electronic device  101 . Accordingly, the front surface of the electronic device  101  may include the display  200 , and a partial area of the first housing structure  310  and a partial area of the second housing structure  320  that are adjacent to the display  200 . The rear surface of the electronic device  101  may include the first rear cover  380 , a partial area of the first housing structure  310  that is adjacent to the first rear cover  380 , the second rear cover  390 , and a partial area of the second housing structure  320  that is adjacent to the second rear cover  390 . 
     According to an embodiment, the display  200  may mean a display of which at least a partial area can be deformed into a flat surface or a curved surface. According to an embodiment, the display  200  may have a folding section  203 , a first section  201  disposed at one side from the folding section  203  (e.g., at the left side of the folding section  203  shown in  FIG. 2 ), and a second section  202  disposed at the other side (e.g., at the right side of the folding section  203  shown in  FIG. 2 ). 
     However, the divided sections of the display  200  shown in  FIG. 2  are examples and the display  200  may be divided into a plurality of sections (e.g., four or more sections), depending on the structure or the function. For example, in the shown embodiment, the folding section  203  is parallel with the y-axis, but in another embodiment, another folding section may be parallel with the x-axis. According to an embodiment, the display  200  may be combined with or disposed adjacent to a touch sensing circuit, a pressure sensor that can measure the intensity (pressure) of a touch, and/or a digitizer that detects a magnetic stylus pen. 
     According to an embodiment, the first section  201  and the second section  202  may be substantially symmetrical to each other, with the exception that the second section  202 , unlike the first section  201 , may have a cut notch corresponding to the sensor section  324 . In other words, the first section  201  and the second section  202  may have portions that are symmetrical to each other and portions that are asymmetric. 
     Hereinafter, the operation of the first housing structure  310 , the second housing structure  320 , and the sections of the display  200  according to whether the electronic device  101  is folded, unfolded, or partially unfolded are described. 
     According to an embodiment, when the electronic device  101  is unfolded (e.g.,  FIG. 2 ), the first housing structure  310  and the second housing structure  320  may be arranged in the same direction to make an angle of 180 degrees. The surface of the first section  201  and the surface of the second section  202  of the display  200  may make 180 degrees and may be arranged to face the same direction (e.g., toward the front surface of the electronic device). The folding section  203  may be coplanar to the first section  201  and the second section  202 . 
     According to an embodiment, when the electronic device  101  is folded (e.g.,  FIG. 3 ), the first housing structure  310  and the second housing structure  320  may be arranged to face each other. The surface of the first section  201  and the surface of the second section  202  of the display  200  may face each other while making a small angle (e.g., between 0 to 10 degrees). The folding section  230  may be folded into an at least partially curved surface having a predetermined curvature. 
     According to an embodiment, when the electronic device  101  is partially unfolded, the first housing structure  310  and the second housing structure  320  may be arranged with a certain angle therebetween. The surface of the first section  201  and the surface of the second section  202  of the display  200  may make an angle that is larger than when folded but smaller than when unfolded. The folding section  203  may be folded into an at least partially curved surface having a second predetermined curvature, where the second curvature may be smaller than that when folded. 
       FIG. 4  is an exploded perspective view of the electronic device according to an embodiment. 
     Referring to  FIG. 4 , in an embodiment, the electronic device  101  may include a foldable housing  300 , a display  200 , and a substrate assembly  520 . The foldable housing may include a first housing structure  310 , a second housing structure  320 , a bracket assembly  340 , a first rear cover  380 , a second rear cover  390 , and a hinge structure  510 . 
     According to an embodiment, the display  200  may include a display panel (e.g.,  200   c  in  FIG. 6 ) (e.g., a flexible display panel) and one or more plates or layers (e.g., a support plate  240 ) on which a display panel  200   b  is seated. In an embodiment, the support plate  240  may be disposed between the display panel  200   b  and the bracket assembly  340 . A bonding structure (not shown) is positioned between the support plate  240  and the bracket assembly  340 , thereby being able to bond the support plate  240  and the bracket assembly  340 . 
     According to an embodiment, the bracket assembly  340  may include a first support plate  410  and a second support plate  420 . Between the first support plate  410  and the second support plate  420 , the hinge structure  510  is disposed, and a hinge cover  330  covering the hinge structure  510  may be disposed when the hinge structure  510  is seen from the outside. As another embodiment, a Flexible Printed Circuit (FPC) may be disposed across the first support plate  410  and the second support plate  420 . 
     According to an embodiment, the substrate assembly  520  may include a first main circuit board  521  disposed at the first support plate  410  and a second main circuit board  522  disposed at the second support plate  420 . The first main circuit board  521  and the second main circuit board  522  may be disposed in a space defined by the bracket assembly  340 , the first housing structure  310 , the second housing structure  320 , the first rear cover  380 , and the second rear cover  390 . Components for implementing various functions of the electronic device  101  may be mounted on the first main circuit board  521  and the second main circuit board  522 . 
     According to an embodiment, the first housing structure  310  and the second housing structure  320  may be assembled to be coupled to both sides of the bracket assembly  340  with the display  200  coupled to the bracket assembly  340 . For example, the first housing structure  310  and the second housing structure  320  may be combined with the bracket assembly  340  by sliding into both sides of the bracket assembly  340 . 
     According to an embodiment, the first housing structure  310  may have a first surface  311  and a second surface  312  facing in the opposite direction to the first surface  311 , and the second housing structure  320  may have a third surface  321  and a fourth surface  322  facing the opposite direction to the third surface  321 . 
     According to an embodiment, the first housing structure  310  may have a first rotary support surface  313  and the second housing structure  320  may have a second rotary support surface  323  corresponding to the first rotary support surface  313 . The first rotary support surface  313  and the second rotary support surface  323  may have a curved surface corresponding to the curved surface of the hinge cover  330 . 
     According to an embodiment, when the electronic device  101  is in the unfolded state (the electronic device in  FIG. 2 ), the first rotary support surface  313  and the second rotary support surface  323  cover the hinge cover  330 , so the hinge cover  330  may not be exposed or may be minimally exposed on the rear surface of the electronic device  101 . As another embodiment, when the electronic device  101  is in the folded state (the electronic device in  FIG. 3 ), the first rotary support surface  313  and the second rotary support surface  323  are rotated along the curved surface of the hinge cover  330 , so the hinge cover  330  may be maximally exposed on the rear surface of the electronic device  101 . 
       FIG. 5A  is a perspective view showing an example of an unfolded electronic device  101  according to an embodiment, and  FIG. 5B  is a perspective view showing an example of a partially folded electronic device  101  according to an embodiment. 
     Referring to  FIGS. 5A and 5B , the electronic device  101  may include a foldable housing  300  and a flexible display  200 . According to two different embodiments, the electronic device  101  may be an in-folding type or an out-folding type. The in-folding type may mean that the flexible display  200  is not exposed to the outside when folded. The out-folding type may mean that the flexible display  200  is exposed to the outside when fully folded.  FIG. 5B  shows an in-folding type. According to another embodiments, the electronic device  101  may be fully foldable in 360 degrees, and thus be both the in-folding type and the out-folding type. 
     In one example, the flexible display  200  may have a rectangular shape with rounded corners and a very narrow bezel. 
     The components of the electronic device  101  shown in  FIGS. 1 to 4  may be the same or similar as those shown in  FIG. 5 . 
     The user can perform inputting using an input device (e.g.,  150  in  FIG. 1 ) on the first section  201 , second section  202 , and the third section  203  of the display  200 . 
       FIG. 6  is a plan view showing spatial relationships of components in the electronic device when unfolded, according to an embodiments. 
     The electronic device  101  includes a foldable housing having a folding section H where the electronic device  101  may be folded about a folding axis. The foldable housing may include a first housing structure  610  and a second housing structure  620 . 
     The foldable housing accommodates at least one printed circuit board, and according to an embodiment, a first printed circuit board  821  and a second printed circuit board  822  may be accommodated in the first housing structure  610  and the second housing structure  620 , respectively. The structures of the printed circuit boards  821  and  822  shown in  FIG. 6  may be partially or wholly the same as the structure of the circuit board  520  shown in  FIG. 4 . 
     According to an embodiment, the first printed circuit board  821  may be a main PCB including a processor  831  (e.g., a processor  120  in  FIG. 1 ), a power management module (e.g., a PMIC), or a radio frequency transceiver. According to an embodiment, the second printed circuit board  822  may be a sub PCB equipped with a communication device  832 . The communication device  832  may be a millimeter wave (mmWave) communication device that performs wireless communication in, for example, frequency bands over 20 GHz and under 100 GHz. According to an embodiment, the communication device  832  and the second printed circuit board  822  may be separate modules, unlike as shown in  FIG. 6 . According to an embodiment, the processor  831  may include at least a Communication Processor (CP) or may be a component formed by integrating an Application Processor (AP) and a CP, and can control or drive the radio frequency transceiver, the power management module, the wireless communication circuit, etc. The radio frequency transceiver may be included in the second printed circuit board  822 , and can transmit/receive Rx digital signals, transmission analog I/Q signals, control signal, etc. to/from the processor  831 . In an embodiment, the radio frequency transceiver can generate and provide communication signals to a wireless communication circuit. 
     According to an embodiment, the first printed circuit board  821  and the second printed circuit board  822  may be supported by a first support  710  disposed in the first housing structure  610  and a second support  720  disposed in the second housing structure  620 , respectively. The first support  710  and the second support  720  can support the first printed circuit board  821  and the second printed circuit board  822 , and can support other components (e.g., batteries  851  and  852 ) that are not mounted on the first printed circuit board  821  and the second printed circuit board  822 . 
     According to an embodiment, various components (e.g., a first camera device  841 ) may be additionally disposed on the first printed circuit board  821 , and various components (e.g., a second camera device  842  and a receiver module  843 ) may be disposed also on the second printed circuit board  822 . It should be noted that the numbers and arrangement of various components are not limited to the embodiment shown in  FIG. 6  in the instant disclosure and these components may be designed in various ways. 
     According to an embodiment, a plurality of connectors C for electrical connection (e.g., transmission of control signals, power, and communication signals) between the various components may be disposed on the first printed circuit board  821  and the second printed circuit board  822 . The plurality of connectors C disposed on the first printed circuit board  821  and the second printed circuit board  822  may employ various types of connection structures (or connector structures) such as a Flexible Printed Circuit (FPC) or a Flexible Flat Cable (FFC) type, a Board-to-Board (B-to-B) type, a zip type, a bonding type formed for a hot bar process, a Low Insertion Force (LIF), and a Zero Insertion Force (ZIF), whereby relevant components can be electrically coupled. 
     In the electronic device  101  according to an embodiment, a Connector-To-Connector (C-to-C or C2C) type electrical connection structure (or connector structure) that connects two different connectors C may be used. C-to-C type electrical connection structures F 1 , F 2 , and F 3  are shown as examples in  FIG. 6 . 
     The electronic device  101  according to an embodiment may include C-to-C type electrical connection structures F 1  and F 2  that connect connectors positioned on different printed circuit boards  821  and  822 . The electrical connection structures F 1  and F 2  may be formed across at least a portion of the first printed circuit board  821  and at least a portion of the second printed circuit board  822 . According to an embodiment, the electrical connection structures F 1  and F 2  may pass through at least a portion of the folding section of the hinge portion H and may be formed across at least a portion of the first printed circuit board  821  and at least a portion of the second printed circuit board  822 . A Flexible Printed Circuit Board (FPCB) may be used to connect two connectors C disposed on different printed circuit boards. By using an FPCB, it is possible to stably achieve and/or maintain electrical connection between the connectors even if a printed circuit board is configured to be bent at least in some section. 
     The positions of the plurality of connectors C may be deigned in various ways, and the electrical connection structures connecting the plurality of connectors C may also be varied. It is required to generally consider the arrangement relationship and convenience of the spatial mounting of components when positioning the plurality of connectors C and determining the types of the electrical connection structures. For example, in order to mount the battery  852  having larger capacity in the electronic device  101 , connectors and electrical connection structures for the connectors may be installed to bypass the area in which the battery  852  is mounted or may be installed to only partially overlap the area, as shown in  FIG. 6 . 
     Many signal lines may be formed and connected to the plurality of connectors and electrical connection structures. Some signal lines (e.g., Mobile Industry Processor Interface (MIPI)) may have a problem related with a signal loss which may be increased when the signal lines formed longer than a designated length, when the signal lines bent, or when other electronic components are disposed around the signal lines. Further, timing delay may occur and performance (e.g., antenna performance) may be deteriorated due to Electro Magnetic Interference (EMI) in the signal lines. 
     According to an embodiment, even if the electronic device  101  is equipped with a battery  852  having larger capacity, it is possible to provide a plurality of connectors and electrical connection structures for the connectors in order to prevent deterioration of performance. 
     According to an embodiment, by providing two different FPCBs F 1  and F 2  installed across portions of the first printed circuit board  821  and portions of the second printed circuit board  822 , it is possible to design an interface in which a plurality of signal lines for performing various functions of the foldable electronic device  101  can be disposed. For example, the electronic device  101  may include a first FPCB F 1  that crosses at least a portion of the first printed circuit board  821  and at least a portion of the second printed circuit board  822  and electrically connects the first printed circuit board  821  and the second printed circuit board  822  through connection terminals at both ends thereof. Further, the electronic device  101  may include a second FPCB F 2  that crosses at least a portion of the first printed circuit board  821  and at least a portion of the second printed circuit board  822  and electrically connects first printed circuit board  821  and the second printed circuit board  822  through connection terminals at both ends thereof. 
     Signal lines having a first signal characteristic may be disposed on the first FPCB F 1  and signal lines having a second signal characteristic may be disposed on the second FPCB F 2 . According to a certain embodiment, the FPCBs F 1  and/or F 2  may be formed at a predetermined length, capable of being bent, and disposed adjacent to a portion (hereafter, referred to as a ‘loss area’) of the first printed circuit board  821  and the second printed circuit board  822  in which other electronic components are disposed around the FPCB. According to an embodiment, when signal lines having a first signal characteristic are more sensitive than signal lines having a second signal characteristic, it is possible to improve integrity of the signals by disposing the second FPCB F 2  adjacent to the loss area and the first FPCB F 1  farther away from the loss area. 
       FIG. 7A  is a perspective view of a flexible printed circuit board (e.g., the first FPCB F 1 ) according to an embodiment.  FIG. 7B  is a front view of the flexible printed circuit board (e.g., the first FPCB F 1 ) according to an embodiment.  FIG. 7C  is a rear view of the flexible printed circuit board (e.g., the first FPCB F 1 ) according to an embodiment. 
     The first FPCB F 1  may include a component for connecting with at least one of a first printed circuit board (e.g.,  821  in  FIG. 6 ) or a second printed circuit board (e.g.,  822  in  FIG. 6 ). According to an embodiment, connection terminals  810  and  820  are formed at both ends of the FPCB F 1 , so the FPCB F 1  can be connected to a first printed circuit board (e.g.,  821  in  FIG. 6 ) or a second printed circuit board (e.g.,  822  in  FIG. 6 ). 
     For example, the first FPCB F 1  may have a first end  810  forming an end of the first FPCB and a second end  820  forming the other end as connection terminals  810  and  820 , and rigid portions  801  and  803  for fixing to the first printed circuit board (e.g.,  821  in  FIG. 6 ) may be formed at the first end  810  and the second end  820 . The rigid portions  801  and  803  may include a first rigid portion  801  and a rigid portion  803 . The first connection terminal  810  is formed at the first rigid portion  801  and may include a plurality of pins C 1  and a reinforcing material surrounding the plurality of pins C 1 . The second connection terminal  820  is formed at the second rigid portion  803  and may include a plurality of pins C 2  and a reinforcing material surrounding the plurality of pins C 2 . The first connection terminal  810  may be a receptacle or a header that includes the plurality of pins C 1  and the reinforcing material. Similarly, the second connection terminal  820  may be a receptacle or a header that includes the plurality of pins C 2  and the reinforcing material. According to an embodiment, the plurality of pins C 1  and C 2  respectively formed on the rear surfaces of the first rigid portion  801  and the second rigid portion  803  may be respectively coupled to the connectors C disposed on the first printed circuit board  821  and the second printed circuit board  822  of the foldable electronic device  101 . 
     According to an embodiment, the first rigid portion  801  and the second rigid portion  803  may have similar layers and structures. However, the disclosure is not necessarily limited thereto. Although the first rigid portion  801  and the second rigid portion  803  have a symmetric shape in the drawings, they are not necessarily limited thereto. 
     According to an embodiment, the first FPCB F 1  may be a multi-layered circuit board in which several conductive layers and several insulating layers are alternately stacked. The first FPCB F 1  may include at least one electrically conductive path connecting a first printed circuit board (e.g.,  821  in  FIG. 6 ) and a second printed circuit board (e.g.,  822  in  FIG. 6 ). For example, the conductive path may be formed on at least one of the several conductive layers and may transmit power or control signals provided from a power management module or a processor. In a certain embodiment, the first FPCB F 1  may include a conductive path (e.g., an RF wiring) for transmitting communication signals provided from an RF transceiver or communication signal received through a communication device to a radio frequency transceiver. Such a conductive path(s) may also be formed on at least one of several conductive layers. 
     The first FPCB F 1  may include a flex portion  802  between the first rigid portion  801  and the second rigid portion  803 . According to various embodiments, the first rigid portion  801  and the flex portion  802  each may include a plurality of conductive layer and a plurality of insulating layer that are separated from each other, and the conductive layers and insulating layers may integrally extend from the first rigid portion  801  and the flex portion  802 . The insulating layer may be Polyimide (PI)-based base material layer such as a Flexible Copper Clad Laminate (FCCL) and the conductive layers may be obtained by forming a thin metal plate (e.g., copper (Cu)) and/or plate a thin cooper layer at least on one surface of a Polyimide (PI)-based base material layer. 
     According to an embodiment, the first FPCB F 1  may further include at least one rigid portion between the first end  810  and the second end  820 . According to the embodiment shown in  FIGS. 7A to 7C , the first FPCB F 1  may further include two rigid portions  804  and  805 . The first FPCB F 1  of the disclosure is disposed through the folding section of the hinge portion H in a foldable electronic device (e.g.,  101  in  FIG. 6 ), so it is possible to provide a more stable coupling structure to a housing for the first FPCB F 1  by additionally including at least one rigid portion. 
       FIG. 8  is a plan view showing when the first FPCB F 1  is mounted on the hinge portion H 1  of a foldable electronic device (e.g.,  101  in  FIG. 6 ) according to an embodiment.  FIG. 9  is a side view showing a cross-section taken along line B-B′ of the foldable electronic device (e.g.  101  in  FIG. 6 ) according to the embodiments shown in  FIG. 8 . 
     Referring to  FIGS. 8 and 9 , the first FPCB F 1  can be combined with a hinge module of the foldable electronic device between the first support  710  and the second support  720 . The first FPCB F 1  has two rigid portions  801  and  803  at both ends and a flex portion  802  between the rigid portions. The flex portion  802  formed between the first rigid portion  801  and the second rigid portion  803  may bend with a predetermined curvature and may be disposed such that a least a portion is surrounded from the hinge structure  811 . 
     The first rigid portion  801  may be disposed in a first housing structure (e.g.,  610  in  FIG. 6 ) of the foldable electronic device, and as shown in  FIG. 9 , may be mounted to face the first printed circuit board  821  in the first housing structure (e.g.,  610  in  FIG. 6 ). The second rigid portion  803  may be disposed in a second housing structure (e.g.,  620  in  FIG. 6 ) of the foldable electronic device, and as shown in  FIG. 9 , may be mounted to face the second printed circuit board  822  in the second housing structure (e.g.,  620  in  FIG. 6 ). 
     The first FPCB F 1  may further have two rigid portions  804  and  805  to be stably combined with the housing, and the two rigid portions  804  and  805  may be fixed to a partial surface of the hinge structure  811 . As shown in  FIG. 8 , according to an embodiment, the two rigid portions  804  and  805  may be exposed when the display is removed from the electronic device (e.g.,  101  in  FIG. 6 ). 
       FIG. 10  is a view showing the first FPCB F 1  and the second FPCB F 2  according to an embodiment. 
     According to an embodiment, the second FPCB F 2  has a third end  910  forming an end of the second FPCB F 2  and a fourth end  920  forming the other end as connection terminals, and rigid portions  901  and  903  for fixing to the first and second printed circuit boards may be formed at the third end  910  and the fourth end  920 . The second FPCB F 2  according to an embodiment may have a flex portion  902  formed between the third rigid portion  901  and the fourth rigid portion  903 . The second FPCB F 2  according to an embodiment additionally has at least one rigid portion  904  and  905  between the third end  910  and the fourth end  920 , and the rigid portions  904  and  905  may be connected and fixed to a hinge structure (e.g.,  811  in  FIG. 9 ). The above description about the first FPCB F 1  referring to  FIGS. 7A to 9  may be used for the second FPCB F 2 . 
     Hereafter, differences between the first FPCB F 1  and the second FPCB F 2  may be described. 
     Referring to  FIG. 10 , the second FPCB F 2  may be longer than the first FPCB F 1 . According to an embodiment, a portion  902 ′ of the flex portion of the second FPCB F 2  is elongated, whereby a signal line longer than the first FPCB F 1  may be formed. For example, when signal lines longer than the first FPCB F 1  are needed, depending on the internal mounting environment of the foldable electronic device, signal lines disposed on the second FPCB F 2  are grouped as signal lines having signal characteristics less sensitive than signal lines disposed on the first FPCB F 1 . Therefore, even when the signal lines of the second FPCB F 2  have increased lengths, interference is minimized. 
     According to an embodiment, at least portions (e.g.,  901 ,  902 ,  903 ,  904 , and  905 ) of the second FPCB F 2  may be disposed in parallel with the first FPCB F 1 , and at least a portion of the second FPCB F 2  may form a bent portion (e.g.,  902 ′) not in parallel with the first FPCB F 1 . Referring to  FIGS. 6 and 10 , in the electronic device  101  according to an embodiment, at least a portion (e.g.,  902 ′) of the second FPCB F 2  may overlap with electronic components such as the battery. The signal lines disposed on the second FPCB F 2  are grouped as signal lines having signal characteristics less sensitive than the signal lines disposed on the first FPCB F 1 , such that interference is minimized. 
     Referring to  FIGS. 6 and 10 , according to an embodiment, while the first end  810  and the second end  820  of the first FPCB F 1  may be disposed to face opposite directions to each other in the electronic device (e.g.,  101  in  FIG. 6 ), the third end  901  and the fourth end  920  of the second FPCB F 2  may be disposed to face perpendicular directions to each other. 
       FIG. 11  is schematic diagrams showing circuits disposed on each layer when the first FPCB F 1  according to an embodiment includes a plurality of layers.  FIG. 12  is schematic diagrams showing circuits disposed on each layer when the second FPCB F 2  according to an embodiment includes a plurality of layers. 
     Referring to  FIG. 11 , the first FPCB F 1  may be a multi-layered circuit board including a plurality of layers, for example, six layers L 1 , L 2 , L 3 , L 4 , L 5 , and L 6 . Obviously, it should be noted that the embodiment shown in  FIG. 11  does not limit the instant disclosure. For example, according to another embodiment, it may be possible to include five layers, and according to yet another embodiment, it may be possible to include seven or more layers. 
     Referring to  FIG. 11 , signal lines S 1 , S 2 , and S 3  that are sensitive to length, width, and interference by other surrounding adjacent electronic components may be disposed on the first FPCB F 1 . For example, when a signal line for Mobile Industry Processor Interface (MIPI) used for high-speed communication to control and drive display and camera is overly long, it is difficult to maintain the impedance of the signal line. Thus, such a MIPI signal line should be formed on the first FPCB F 1 . As another example, when power wiring to which a high current is applied is overly long, voltage drop may occur that may cause the electronic device (e.g.  101  in  FIG. 6 ) to turn off. Accordingly, this power wiring should also be disposed on the first FPCB F 1  on which as short signal lines as possible can be formed. According to another embodiment, signal lines having sensitive signal characteristics such as wireless charging/NFC lines may be disposed on the first FPCB F 1 . 
     According to an embodiment, rigid portions  801 ,  803 ,  804 , and  805  may be formed on a first layer L 1  and a second layer L 6  of the first FPCB F 1 , and the flex portion  802  may be formed on a second layer L 2 , a third layer L 3 , a fourth layer L 4 , and a fifth layer L 5  of the first FPCB F 1 . According to an embodiment, signal lines may be formed on at least any one of the second layer L 2 , the third layer L 3 , the fourth layer L 4 , and the fifth layer L 5 . 
     According to an embodiment, an MIPI signal line S 3  for performing high-speed communication (e.g., a first-first signal line) may be formed on the fifth layer L 5  that is close to a plurality of pins C 1  and C 2 . In this case, there may be an advantage in that the size of via and the length of wirings are minimized and it is possible to minimize communication loss. According to an embodiment, a power wiring (e.g., a system power wiring) (e.g., a first-second signal line) S 1  may be disposed on the second layer L 2  closest to the first layer L 1 . When the high-speed communication signal MIPI S 3  is formed on the fifth layer L 5 , it is possible to minimize the noise between the power wiring S 1  and the MIPI wiring S 3  by disposing them as far away from each other as possible. 
     According to an embodiment, at least one layer having grounds G 1  and G 2  may be provided between the high-speed communication signal line S 3  and the power wiring line S 1 . According to an embodiment, it is possible to dispose another power wiring (e.g., battery power wiring S 1 ) away from the high-speed communication signal line S 3  by disposing the power wiring on the layer L 3  adjacent to the layer L 2  on which the system power line S 1  is formed. According to an embodiment, it is possible to form an electromagnetic shield structure by forming an anti-EMI film to prevent EMI. For example, it is possible to form an electromagnetic shield structure by disposing an anti-EMI film to surround at least portions of the fifth layer on which the high-speed communication signal line S 3  and the second layer on which the power wiring (e.g., system power wiring) S 1  is disposed. 
     Referring to  FIG. 12 , signal lines (e.g., T 1 , T 2 , and T 3 ) that are less sensitive to length, width, and interference by other surrounding adjacent electronic components may be disposed on the second FPCB F 2 . For example, an I2C for low-speed communication may be disposed on the second FPCB F 2 . As other examples, power wirings of RCV, interrupt, motor, and proximity sensor may be formed on the second FPCB F 2 . 
     According to an embodiment, wiring for a main battery may be disposed on the first FPCB F 1  and wiring for a sub battery may be disposed on the second FPCB F 2 . 
     The second FPCB F 2  according to an embodiment may also include at least one via. A ground may be formed on at least some of the plurality of conductive layers of the second FPCB F 2 . 
       FIG. 13A  is a schematic diagram showing a layer L 6  having a plurality of pins when a flexible printed circuit board (e.g., the first FPCB F 1 ) according to an embodiment includes a plurality of layers.  FIG. 13B  is a schematic diagram showing a layer L 5  having a signal line that can perform high-speed communication when a flexible printed circuit board (e.g., the first FPCB F 1 ) according to an embodiment includes a plurality of layers. 
     According to an embodiment, the first FPCB F 1  may include a layer L 6  having a first connector at an end  1010  and a second connector corresponding to the first connector at the other end  1020 . The first connector and the second connector may include parallel pin connectors each having at least two lines of pins P 11  and P 12  and P 21  and P 22 . 
     Referring to  FIG. 13A , in the electronic device according to an embodiment (e.g.,  101  in  FIG. 6 ), the first connector may have a first-first pin P 11  formed at the outermost side of the first FPCB F 1  and a first-second pin P 12  formed inside the first-first pin P 11 . The second connector may have a second-first pin P 21  formed at the outermost side of the first FPCB F 1  and a second-second pin P 22  formed inside the second-first pin P 21 . 
     Referring to  FIG. 13B , signals lines (e.g., MIPI signal lines) corresponding to the parallel pins shown in  FIG. 13A  are shown. The line  1  may be a signal line disposed at a position corresponding to the first-first pin P 11  and the second-first pin P 21  of the first connector and the line  2  may be a signal line disposed at a position corresponding to the first-second in P 12  and the second-second pin P 22  of the first connector. 
     According to the embodiment shown in  FIGS. 13A and 13B , an embodiment having an out-out wiring structure connected with signal lines (e.g., the line  1 ) corresponding to the pin formed at the outermost side of a connector and an in-in wiring structure connected with signal lines (e.g., the line  2 ) corresponding to the pins formed inside the connector may be shown. According to an embodiment, the out-out wiring structure may have a larger wiring length than the in-in wiring structure. Accordingly, the arrival time of data transmitted to the out-out wiring structure may be larger than the arrival time of data transmitted to the in-in wiring structure (timing skew). According to an embodiment, it may be considered to elongate the in-in wiring section such that the arrival time of data transmitted to the in-in wiring section is close to the arrival time of data transmitted to the out-out wiring section, and to this end, an end of the in-in wire may be formed at least partially have a skew shape. 
       FIG. 14A  is a schematic diagram showing a layer L 6  having a plurality of pins when a flexible printed circuit board (e.g., the first FPCB F 1 ) according to an embodiment includes a plurality of layers.  FIG. 14B  is a schematic diagram showing a layer L 5  having a signal line that can perform high-speed communication when a flexible printed circuit board (e.g., the first FPCB F 1 ) according to an embodiment includes a plurality of layers. 
     According to an embodiment, the first FPCB F 1  may include a layer L 6  having a first connector at an end  1010  and a second connector corresponding to the first connector at the other end  1020 . The first connector and the second connector may be parallel pin connectors each having at least two lines of pins P 11  and P 12  and P 21  and P 22 . 
     Referring to  FIG. 14A , in the same way as the embodiment shown in  FIG. 13A , the first connector may have a first-first pin in P 11  formed at the outermost side of the first FPCB F 1  and a first-second pin P 12  formed inside the first-first pin P 11  and the second connector may include a second-first pin P 21  formed at the outermost side of the first FPCB F 1  and a second-second pin P 22  formed inside the second-first pin P 21 . 
     Referring to  FIG. 14B , signals lines (e.g., MIPI signal lines) corresponding to the parallel pins shown in  FIG. 14A  are shown. The line  1  may be a signal line disposed at a position corresponding to the first-first pin P 11  and the second-second pin P 22  of the first connector and the line  2  may be a signal line disposed at a position corresponding to the first-second pin in P 12  and the second-first pin P 21  of the first connector. 
     Signal lines according to the embodiment shown in  FIGS. 14A and 14B  may show an embodiment having an out-in wiring (e.g., line  1 ) and an in-out wiring structure (e.g., line  2 ). According to this embodiment, there is an advantage in that line  1  and line  2  may have approximately the same lengths and the wiring may be easy. When the lengths of line  1  and line  2  are close, it is possible to minimize timing skew and minimize inter-signal delay. Further, when line  1  and line  2  having close lengths are included, there may be no need for an additional wiring for reducing the timing skew or delay. 
     An electronic device according to various embodiments disclosed herein may be various types of devices. The electronic devices may include, for example, a portable communication device (e.g., a smart phone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, or a home appliance. According to an embodiment, the electronic devices are not limited to those described above. 
     It should be appreciated that various embodiments of the disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular embodiments and include various changes, equivalents, or replacements for a corresponding embodiment. With regard to the description of the drawings, similar reference numerals may be used to refer to similar or related elements. It is to be understood that a singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise. As used herein, each of such phrases as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and “at least one of A, B, or C,” may include all possible combinations of the items enumerated together in a corresponding one of the phrases. As used herein, such terms as “1st” and “2nd,” or “first” and “second” may be used to simply distinguish a corresponding component from another, and does not limit the components in other aspect (e.g., importance or order). It is to be understood that if an element (e.g., a first element) is referred to, with or without the term “operatively” or “communicatively”, as “coupled with,” or “connected with,”, it means that the element may be coupled with the other element directly (e.g., wiredly), wirelessly, or via a third element. 
     According to various embodiments, each component (e.g., a module or a program) of the above-described components may include a single entity or multiple entities. According to various embodiments, one or more components of the above-described components or operations may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components (e.g., modules or programs) may be integrated into a single component. In such a case, according to various embodiments, the integrated component may still perform one or more functions of each of the plurality of components in the same or similar manner as they are performed by a corresponding one of the plurality of components before the integration. According to various embodiments, operations performed by the module, the program, or another component may be carried out sequentially, in parallel, repeatedly, or heuristically, or one or more of the operations may be executed in a different order or omitted, or one or more other operations may be added. 
     According to an embodiment, there may be provided an electronic device (e.g.  101  in  FIG. 4 ), in which a foldable housing includes a hinge structure (e.g.,  510  in  FIG. 4 ) having a folding axis, and a folding section where the electronic device is folded about the folding axis, a first housing structure (e.g.,  610  in  FIG. 6 ) connected to the hinge structure, having a first surface (e.g.,  311  in  FIG. 4 ) facing a first direction and a second surface (e.g.,  312  in  FIG. 4 ) facing a second direction opposite to the first direction, and including a first printed circuit board (e.g.,  821  in  FIG. 6 ) having a plurality of electronic components mounted thereon; and a second housing structure (e.g.,  620  in  FIG. 6 ) connected to the hinge structure, having a third surface (e.g.  321  in  FIG. 4 ) facing a third direction and a fourth surface (e.g.,  322  in  FIG. 4 ) facing a fourth direction opposite to third direction, including a second printed circuit board (e.g.,  822  in  FIG. 6 ) having a plurality of electronic components mounted thereon. The second housing structure is configured to be foldable on the first housing structure around the hinge structure. The electronic device further includes: a flexible display (e.g.,  200  in  FIG. 4 ) disposed in the foldable housing and extending from the first surface of the first housing structure to the third surface of the second housing structure; a first flexible printed circuit board (e.g., F 1  in  FIG. 6 ) crossing at least a portion of the hinge structure and electrically connecting the first printed circuit board and the second printed circuit board through connection terminals at both ends thereof; and a second flexible printed circuit board (e.g., F 2  in  FIG. 6 ) crossing at least a portion of the hinge structure and electrically connecting the first printed circuit board and the second printed circuit board through connection terminals at both ends thereof, in which signal lines (e.g., S 1 , S 2 , and S 3  in  FIG. 11 ) having a first signal characteristic are disposed on the first flexible printed circuit board and signal lines (e.g., T 1 , T 2 , and T 3  in  FIG. 12 ) having a second signal characteristic are disposed on the second flexible printed circuit board. 
     According to an embodiment, the second flexible printed circuit board may be formed longer than the first flexible printed circuit board. 
     According to an embodiment, at least a portion of the second flexible printed circuit board may be parallel with the first flexible printed circuit board, and at least another portion of the second flexible printed circuit board may not be parallel with the first flexible printed circuit board and may have a bent portion (e.g.,  902 ′ in  FIG. 10 ). 
     According to an embodiment, the other portion of the second flexible printed circuit board may overlap the plurality of electronic components. 
     According to an embodiment, the other portion of the second flexible printed circuit board may overlap a battery ( 852  in  FIG. 6 ). 
     According to an embodiment, the first connection terminals may be disposed at a first end (e.g.  810  in  FIG. 10 ) and a second end (e.g.  820  in  FIG. 10 ) of the first flexible printed circuit board, first rigid portions (e.g.  801  and  803  in  FIG. 10 ) for fixing the first flexible printed circuit board to the first printed circuit board and the second printed circuit board may be formed at the first end and the second end, the second connection terminals may be disposed at a third end (e.g.  910  in  FIG. 10 ) and a fourth end (e.g.  920  in  FIG. 10 ) of the second flexible printed circuit board, and second rigid portions (e.g.  901  and  903  in  FIG. 10 ) for fixing the second flexible printed circuit board to the first printed circuit board and the second printed circuit board may be formed at the third end and the fourth end. 
     According to an embodiment, the first end and the second end may face opposite directions, and the third end and the fourth end may face directions perpendicular to each other. 
     According to an embodiment, the first flexible printed circuit board may further have at least one third rigid portion (e.g.,  804  and  805  in  FIG. 10 ) between the first end and the second end, and the second flexible printed circuit board may further have at least one rigid fourth portion ( 904  and  905  in  FIG. 10 ) between the third end and the fourth end. 
     According to an embodiment, the at least one third rigid portion and the at least one fourth rigid portion may be configured to be connected and fixed to the hinge structure. 
     According to an embodiment, the first signal lines may be signal lines that perform communication at a relatively higher speed than the second signal lines or may be signal lines through which a relatively higher current flows. 
     According to an embodiment, the first flexible printed circuit board may include a first-first signal line (e.g., S 1  in  FIG. 11 ) and a first-second signal line (e.g., S 3  in  FIG. 11 ) disposed on different layers, and a ground (e.g., G 1  and/or G 2  in  FIG. 11 ) between the first-first signal line and a layer having the first-second signal line. 
     According to an embodiment, the first flexible printed circuit board may include a layer (e.g., L 6  in  FIG. 11 ) having a first connector (e.g., C 1  in  FIG. 11 ) formed at an end and a second connector (e.g., C 2  in  FIG. 11 ) corresponding to the first connector and formed at the other end, in which the first connector and the second connector may be parallel pin connectors each having at least two lines of pins. 
     According to an embodiment, the first connector may have a first-first line of pins (e.g., P 11  in  FIG. 14A ) formed at the outermost side of the first flexible printed circuit board and a first-second line of pins (e.g., P 12  in  FIG. 14A ) formed inside the first-first line of pins, the second connector may have a second-first line of pins (e.g., P 21  in  FIG. 14A ) formed at the outermost side of the first flexible printed circuit board and a second-second line of pins (e.g., P 22  in  FIG. 14A ) formed inside the second-first line of pins. The first flexible printed circuit board may further include a first signal line (e.g. line  1  in  FIG. 14B ) connected from the first-first line of pins (e.g., P 11  in  FIG. 14A ) to the second-second line of pins (e.g., P 22  in  FIG. 14A ), and a second signal line connected from the first-second line of pins (e.g., P 12  in  FIG. 14A ) to the second-first line of pins (e.g., P 21  in  FIG. 14A ). 
     According to an embodiment, a layer (e.g., L 5  in  FIG. 14B ) on which the first signal line and the second signal line is disposed may be stacked adjacent to a layer (e.g., L 6  in  FIG. 14A ) having the first connector and the second connector. 
     According to an embodiment, the first signal line (e.g., line  1  in  FIG. 14B ) and the second signal line (e.g., line  2  in  FIG. 14B ) each may correspond to a Mobile Industry Processor Interface (MIPI). 
     According to an embodiment, an electronic device (e.g.,  101  in  FIG. 6 ) includes: a housing: a first printed circuit board (e.g.,  821  in  FIG. 6 ) disposed in the housing; a second printed circuit board (e.g.,  822  in  FIG. 6 ) disposed in the housing and spaced apart from the first printed circuit board; a first flexible printed circuit board (e.g., F 1  in  FIG. 6 ) electrically connecting the first printed circuit board and the second printed circuit board; and a second flexible printed circuit board (e.g., F 2  in  FIG. 6 ) electrically connecting the first printed circuit board and the second printed circuit board, in which the second flexible printed circuit board may be longer than the first flexible printed circuit board. 
     According to an embodiment, at least a portion of the second flexible printed circuit board may be disposed in parallel with the first flexible printed circuit board. 
     According to an embodiment, first signal lines may be disposed on the first flexible printed circuit board and second signal lines different in signal characteristic from the first signal lines may be disposed on the second flexible printed circuit board. 
     According to an embodiment, the first connector may have a first-first line of pins (e.g., P 11  in  FIG. 14A ) formed at the outermost side of the first flexible printed circuit board and a first-second line of pins (e.g., P 12  in  FIG. 14A ) formed inside the first-first line of pins, the second connector may have a second-first line of pins (e.g., P 21  in  FIG. 14A ) formed at the outermost side of the first flexible printed circuit board and a second-second line of pins (e.g., P 22  in  FIG. 14A ) formed inside the second-first line of pins. The first flexible printed circuit board may further include a first signal line (e.g. line  1  in  FIG. 14B ) connected from the first-first line of pins (e.g., P 11  in  FIG. 14A ) to the second-second line of pins (e.g., P 22  in  FIG. 14A ), and a second signal line (e.g., line  2  in  FIG. 13B ) connected from the first-second line of pins (e.g., P 12  in  FIG. 14A ) to the second-first line of pins (e.g., P 21  in  FIG. 14A ). 
     According to an embodiment, the first signal line (e.g., line  1  in  FIG. 14B ) and the second signal line (e.g., line  2  in  FIG. 14B ) may correspond to a Mobile Industry Processor Interface (MIPI). 
     While the disclosure has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims.