Patent Publication Number: US-11665836-B2

Title: Electronic apparatus including flexible display

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 16/857,048, filed on Apr. 23, 2020, which claims the benefit of earlier filing date and right of priority to International Application No. PCT/KR2020/001669, filed on Feb. 5, 2020, the contents of which are all hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     1. Field 
     This disclosure relates to an electronic apparatus including a flexible display. 
     2. Description of the Related Art 
     Recently, with developments of digital technologies, various types of electronic devices such as a mobile communication terminal, a smartphone, a tablet personal computer (PC), a notebook, a personal digital assistant (PDA), a wearable device, or a digital camera are widely used. 
     As performances of the electronic devices are improved, a desire for a large-area display that more efficiently provides various functions has increased. Meanwhile, the electronic device is required to be smaller and thinner to achieve increased portability, which conflicts with an electronic device having a large-area display. 
     Accordingly, research is conducted on an electronic device equipped with a flexible display (e.g., a foldable display, a rollable display, etc.) having a sufficient elasticity such that at least a portion of the display is folded or rolled when being carried and unfolded or spread to be used as necessary. 
     SUMMARY 
     In a case in which an electronic apparatus includes a flexible display, an external material may frequently flow into the electronic apparatus, for example, a space between the flexible display and a frame supporting the flexible display as an operation of changing a shape of the flexible display is repeated. 
     When the external material enters inside the electronic apparatus, the flexible display or a component of the electronic apparatus may be damaged due to the external material. Thus, there is a desire for a structure of the electronic apparatus that blocks an inflow of the external material or easily discharge the external material even if the external material enters the electronic apparatus. 
     According to an aspect, there is provided an electronic apparatus including a flexible display, a frame part configured to support the flexible display, and a rear cover attached to an outer surface of the frame part to cover at least a portion of the frame part, wherein the rear cover is disposed to be detachable from the frame part based on an electrical signal. 
     According to another aspect, there is also provided an electronic apparatus including a flexible display including a first area in which an image is displayed on a front surface of the electronic apparatus, a second area in which an image is displayed on a rear surface of the electronic apparatus, and a third area between the first area and the second area, wherein a position of the third area is changed, a frame part including a first frame that supports at least a portion of the first area and a second frame that supports the second area, and a rear cover attached to the second frame on the rear surface of the electronic apparatus, wherein the rear cover is detached from the second frame based on an electrical signal. 
     According to another aspect, there is also provided an electronic apparatus including a flexible display including a first area in which an image is displayed on a front surface of the electronic apparatus, a second area in which an image is displayed on a rear surface of the electronic apparatus, and a third area between the first area and the second area, a position of the third area being changed, a third frame configured to cover the third area of the flexible display, and at least one structure provided between the flexible display and the third frame to block an inflow of an external material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a block diagram illustrating an electronic apparatus according to example embodiments of the present disclosure; 
         FIG.  2 A  is a front perspective view illustrating an electronic apparatus according to an example embodiment of the present disclosure; 
         FIG.  2 B  is a front perspective view illustrating an electronic apparatus according to an example embodiment of the present disclosure; 
         FIG.  3 A  is a rear perspective view illustrating an electronic apparatus according to an example embodiment of the present disclosure; 
         FIG.  3 B  is a rear perspective view illustrating an electronic apparatus according to an example embodiment of the present disclosure; 
         FIG.  4    is an exploded perspective view illustrating an electronic apparatus according to an example embodiment of the present disclosure; 
         FIG.  5    is a cross-sectional view illustrating an internal structure of an electronic apparatus according to an example embodiment of the present disclosure; 
         FIGS.  6 A through  6 C  are views illustrating a configuration of a coupling member according to an example embodiment of the present disclosure; 
         FIG.  7 A  is a view illustrating a position in which a second element is disposed according to an example embodiment of the present disclosure; 
         FIG.  7 B  is a side sectional view illustrating an electronic apparatus according to an example embodiment of the present disclosure; 
         FIG.  7 C  is a side sectional view illustrating an electronic apparatus according to an example embodiment of the present disclosure; 
         FIGS.  8 A and  8 B  are views illustrating a structure of an electronic apparatus according to an example embodiment of the present disclosure; 
         FIGS.  9 A and  9 B  are views illustrating a first structure according to example embodiments of the present disclosure; and 
         FIGS.  10 A through  100    are views illustrating a structure for discharging a foreign substance according to example embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, and the same or similar elements are designated with the same numeral references regardless of the numerals in the drawings and their redundant description will be omitted. A suffix “module” or “unit” used for constituent elements disclosed in the following description is merely intended for easy description of the specification, and the suffix itself does not give any special meaning or function. In describing the present disclosure, moreover, the detailed description will be omitted when a specific description for publicly known technologies to which the invention pertains is judged to obscure the gist of the present disclosure. Also, it should be noted that the accompanying drawings are merely illustrated to easily explain the concept of the invention, and therefore, they should not be construed to limit the technological concept disclosed herein by the accompanying drawings. 
     The terms ‘first’, ‘second’, etc. may be used to describe various components, but the components are not limited by such terms. The terms are used only for the purpose of distinguishing one component from other components. 
     When an arbitrary component is described as “being connected to” or “being linked to” another component, this should be understood to mean that still another component(s) may exist between them, although the arbitrary component may be directly connected to, or linked to, the corresponding other component. In contrast, when an arbitrary component is described as “being directly connected to” or “being directly linked to” another component, this should be understood to mean that no component exists between them. 
     A singular expression can include a plural expression as long as it does not have an apparently different meaning in context. 
     In the present application, the terms “include” and “have” should be understood to be intended to designate that illustrated features, numbers, steps, operations, components, parts or combinations thereof exist and not to preclude the existence of one or more different features, numbers, steps, operations, components, parts or combinations thereof, or the possibility of the addition thereof. 
     An electronic device according to various embodiments may include at least one of a mobile phone, a smartphone, a laptop computer, a digital broadcasting terminal, personal digital assistants (PDA), a portable multimedia player (PMP), a navigator, a slate PC, a tablet PC, an ultrabook, a wearable device (e.g., smartwatch), a smart glass, a head-mounted display (HMD), a digital TV, a desktop computer, or a digital signage. 
       FIG.  1    is a block diagram illustrating an electronic apparatus according to example embodiments of the present disclosure. 
     Referring to  FIG.  1   , an electronic apparatus  100  may include at least one of a wireless communicator  110 , an input part  120 , a sensing part  140 , an output part  150 , an interface  160 , a memory  170 , a controller  180 , and a power supply  190 . 
     The electronic apparatus  100  may include other components in addition to the components of  FIG.  1    and may also include some of the components of  FIG.  1   . 
     The wireless communicator  110  may include at least one module that enables wireless communication to be performed between the electronic apparatus  100  and a wireless communication system, between the electronic apparatus  100  and another electronic apparatus (not shown) (e.g., the electronic apparatus  100 ), or between the electronic apparatus  100  and an external server. The wireless communicator  110  may include one or more modules that connect the electronic apparatus  100  to one or more networks. The wireless communicator  110  may include at least one of a broadcast receiving module  111 , a mobile communication module  112 , a wireless Internet module  113 , a short-range communication (e.g., near-field communication (NFC)) module  114 , and a position information module  115 . 
     The input part  120  may include at least one of an image input part (for example, a camera  121 ) that receives an image signal input, an audio input part (for example, a microphone  122 ) that receives an audio signal input, or a user input part  123  that receives a user input. For example, the user input part  123  may receive a user touch input through a touch sensor (or touch panel) provided in a display  151  or receive a user input through a mechanical key. Information collected in the input part  120  (for example, voice data and image data) may be analyzed and processed as a control command of a user. 
     The sensing part  140  may include one or more sensors to sense at least one of information in the electronic apparatus  100 , surrounding environment information of the electronic apparatus  100 , or user information. 
     For example, the sensing part  140  may include at least one of a proximity sensor  141 , an illumination sensor  142 , a temperature sensor  143 , a gyroscope sensor  144 , and an acceleration sensor  145 . In addition, the sensing part  140  may include a touch sensor, a finger scan sensor, a magnetic sensor, a gravity (G)-sensor, a motion sensor, an RGB sensor, an infrared (IR) sensor, an ultrasonic sensor, an optical sensor, a battery gauge, an environment sensor (for example, a barometer, a hygrometer, a thermometer, a radioactivity sensor, a heat sensor, and a gas detection sensor), or a chemical sensor (for example, an electronic nose, a healthcare sensor, and a biometric sensor). 
     In the present disclosure, the electronic apparatus  100  may use a combination of pieces of information sensed in at least two sensors among the aforementioned sensors. 
     The output part  150  may output information related to visual, auditory, or tactile. For example, the output part  150  may include at least one of the display  151 , an acoustic output module  152 , a haptic module  153 , or an optical output part  154 . 
     The display  151  may form a layer structure with a touch sensor or be integrally formed with the touch sensor, thereby implementing a touch screen that provides a touch input function and a screen display function simultaneously. For example, the touch screen may function not only as the user input part  123  that provides an input interface between the electronic apparatus  100  and a user but also as the output part  150  that provides an output interface between the electronic apparatus  100  and the user. 
     The electronic apparatus  100  may include the display  151  to display the image information. The display  151  may be a flexible type display to be rolled, bent, or folded. The flexible display may be manufactured on a thin and flexible substrate so as to be curved, bent, folded, twisted, or rolled like a paper while having a characteristic of a typical flat panel display. 
     The flexible display may implement a flexible touch screen in combination with a touch sensor. For example, the controller  180  may sense a touch input through the flexible touch screen of the flexible display and perform various functions corresponding to the touch input. 
     The electronic apparatus  100  may include a deformation detection means (not shown) that detects a change in shape of the flexible display. The electronic apparatus  100  may sense the change in shape of the flexible display using at least one component of the sensing part  140 . For example, based on the change in shape of the flexible display sensed by at least one of the deformation detection means (not shown) or the sensing part  140 , the controller  180  may change information displayed on the flexible display or generate a control signal. 
     The change in shape of the flexible display may include, for example, a change in size of a flexible display area viewable through the first surface (e.g., the front surface) of the electronic apparatus  100 . For example, in response to a partial area of the flexible display being rolled, folded, or bent, a size of an image display area of the flexible display facing the first surface of the electronic apparatus  100  may be increased or reduced. 
     The change in shape of the flexible display may be caused based on an external force applied by a user but not limited thereto. The electronic apparatus  100  may automatically change the shape of the flexible display based on, for example, a predetermined application command or an input through the input part  120  or the sensing part  140 . The electronic apparatus  100  may further include a driving part for changing the shape of the display. For example, the electronic apparatus  100  may change a position at which the flexible display is rolled or bent in response to the driving part being operated, thereby increasing or reducing the size of the flexible display viewable on the first surface. The driving part may be operated under a control of the controller  180 . 
     The audio output module  152  may externally output audio data stored in the memory  170  or received from the wireless communicator  110  in a call signal reception, a call mode or a recording mode, a voice recognition mode, a broadcast reception mode, or the like. The audio output module  152  may output an acoustic signal associated with a function (for example, a call signal reception sound and a message reception sound) performed in the electronic apparatus  100 . For example, the audio output module  152  may include at least one of a receiver, a speaker, or a buzzer. 
     The haptic part  153  may generate various tactile effects to be experienced by a user. A vibration may be a representative example of the tactile effects generated by the haptic part  153 . An intensity and a pattern of the vibration generated by the haptic part  153  may be determined based on a selection of a user or setting of the controller  180 . For example, the haptic part  153  may output a combination of different vibrations or output different vibrations in sequence. 
     The optical output part  154  may output a signal to announce an event occurrence using light of a light source of the electronic apparatus  100 . For example, an event occurring in the electronic apparatus  100  may include at least one of message reception, call signal reception, missed call, alarm, schedule notification, e-mail reception, and application-based information reception. 
     The interface  160  may function as a passage to various types of external devices connected to the electronic apparatus  100 . For example, the interface  160  may include at least one of a wired/wireless headset port, an external charger port, a wired/wireless data port, a memory card port, a port connecting a device equipped with an identification module, an audio input/output (I/O) port, a video I/O port, and an earphone port. In response to the interface  160  being connected to an external device, the electronic apparatus  100  may perform a control or a function associated with the connected external device. 
     The memory  170  may store data related to various functions of the electronic apparatus  100 . For example, the memory  170  may store application programs (or applications) run in the electronic apparatus  100 , data for operation of the electronic apparatus  100 , and instructions. As an example, at least a portion of the application programs may be downloaded from an external server through wireless communication. As another example, at least a portion of the application programs may be previously stored in the memory  170  for a function (for example, call forwarding and outgoing function and message receiving and outgoing function) of the electronic apparatus  100 . The application program stored in the memory  170  may be run to perform a predetermined operation (or function) of the electronic apparatus  100  based on the controller  180 . 
     The controller  180  (e.g., processor) may control an overall operation of the electronic apparatus  100 . For example, the controller  180  may process a signal, data, information, and the like input or output through components of the electronic apparatus  100  or run the application program stored in the memory  170 , thereby providing information to a user or performing a predetermined function. 
     For example, to run the application program stored in the memory  170 , the controller  180  may control at least a portion of the components of the electronic apparatus  100  of  FIG.  1   . To run the application program, the controller  180  may operate a combination of two or more components among the components included in the electronic apparatus  100 . 
     The power supply  190  may supply power to each component included in the electronic apparatus  100  by receiving external or internal power based on a control of the controller  180 . The power supply  190  may include a battery. The battery may include a built-in battery or a removable battery. 
     At least a portion of the aforementioned components of the electronic apparatus  100  may operate in cooperation with each other to implement an operation, a control, or a control method of the electronic apparatus  100  according to various embodiments as described below. Also, the operation, control, or control method of the electronic apparatus  100  may be embodied by running at least one application program stored in the memory  170 . 
     The electronic apparatus  100  may be in a bar shape. However, embodiments are not limited thereto. The electronic apparatus  100  may have various shapes within the scope of not contradicting features of the present disclosure. 
       FIGS.  2 A and  2 B  are front perspective views illustrating the electronic apparatus  100  according to an example embodiment of the present disclosure.  FIGS.  3 A and  3 B  are rear views illustrating the electronic apparatus  100  of  FIGS.  2 A and  2 B . 
     Referring to  FIGS.  2 A through  3 B , the electronic apparatus  100  may include the flexible display  151  that may increase or reduce an image output area viewable on a first surface (e.g., a front surface) of the electronic apparatus  100 , that is, an area (e.g., a first area  151 F) of the display  151  facing the first surface. 
       FIGS.  2 A and  3 A  may correspond to a state in which the first area  151 F is reduced in the electronic apparatus  100 . Also,  FIGS.  2 B and  3 B  may correspond to a state in which the first area  151 F is increased in the electronic apparatus  100 . 
     According to example embodiments, the flexible display  151  may be rolled, folded, or bent at a partial area (e.g., a third area  151 C). Also, in response to a change in position of the partial area, a size of the first area  151 F of the display  151  facing the first surface of the electronic apparatus  100  may be increased or reduced. 
     For example, the flexible display  151  may include the first area  151 F facing the first surface (e.g., the front surface) of the electronic apparatus  100 , a second area  151 R facing a second surface (e.g., a rear surface) of the electronic apparatus  100 , and the third area  151 C located between the first area  151 F and the second area  151 R. 
     The first area  151 F may be, for example, an area in which an image is displayed on the first surface (e.g., the front surface) of the electronic apparatus  100  and may include a display area viewable from outside through the first surface. The second area  151 R may be, for example, an area in which an image is displayed on the second surface (e.g., the rear surface) of the electronic apparatus  100  and may include a display area viewable from outside through the second surface. 
     The first area  151 F may include a fixed area  151 U and a variable area  151 X. For example, even when the first area  151 F is maximally reduced, the fixed area  151 U may correspond to an area of the display  151  viewable on the first surface of the electronic apparatus  100 . Also, the variable area  151 X may correspond to an area of the display  151  additionally viewable on the first surface of the electronic apparatus  100  as the first area  151 F increases. A size of the variable area  151 X may vary based on a degree of moving a position at which the third area  151 C is rolled, bent, and folded in the display  151 . Meanwhile, the fixed area  151 U may be maintained irrespective of a positional change of the third area  151 C. 
     The electronic apparatus  100  may include components (e.g., a driving part and a frame part) for moving the rolled, bent, and folded area of the flexible display  151 . For example, the electronic apparatus  100  may include a driving part (not shown) to move the position of the third area  151 C at which the flexible display  151  is rolled, bent or folded. 
     The driving part may increase or reduce the size of the first area  151 F of the flexible display  151  facing one surface (e.g., the first surface) of the electronic apparatus  100 . For example, the driving part may withdraw a portion (e.g., the second area  151 R) of the display  151  facing the second surface of the electronic apparatus  100  and position the portion to face the first surface. Also, the driving part may insert a portion (e.g., the first area  151 F) of the display  151  facing the first surface and position the portion to face the second surface. 
     The driving part may be disposed adjacent to the third area  151 C. For example, as illustrated in  FIGS.  2 A and  2 B , the third area  151 C may be disposed adjacent to a right side surface (e.g., a side surface portion of a second frame  220 ) based on the front surface of the electronic apparatus  100 . Also, the driving part may be disposed on an inner side of the third area  151 C to be adjacent to the third area  151 C. In this case, as illustrated in  FIGS.  2 A and  2 B , the variable area  151 X may be located adjacent to the second frame  220  and the fixed area  151 U may be located adjacent to a first frame  210 . 
     Although not shown, in some cases, the third area  151 C may be located adjacent to a left side surface (e.g., a side surface portion of the first frame  210 ) of the electronic apparatus  100  based on the front surface of the electronic apparatus  100  and the driving part may be disposed adjacent to the third area  151 C. In such cases, unlike  FIGS.  2 A and  2 B , the variable area  151 X may be located adjacent to the first frame  210  and the fixed area  151 U may be located adjacent to the second frame  220 . 
     Meanwhile, the electronic apparatus  100  may include the first frame  210  and the second frame  220  as a frame part for supporting the flexible display  151  and other components in the electronic apparatus  100 . 
     The first frame  210  and the second frame  220  may be disposed to slidably move in a direction in which a distance therebetween increases or decreases. 
     For example, the second frame  220  may move relative to the first frame  210  in response to a change in shape of the display  151 . In response to the second frame  220  moving relative to the first frame  210 , the size of the first area  151 F or the second area  151 R of the display  151  may be increased or reduced. 
     For example, the second frame  220  may slide relative to the first frame  210  in a direction in which a distance from the first frame  210  increases (e.g., +x direction), so that a display portion of the third area  151 C or the second area  151 R is withdrawn to the first surface (e.g., the front surface) as the variable area  151 X of the first area  151 F. In this example, the first area  151 F may be increased and the second area  151 R may be reduced. 
     Conversely, when the second frame  220  relatively moves in a direction in which the distance from the first frame  210  decreases (e.g., −x direction), at least a portion of the variable area  151 X may be rolled into the second surface (e.g., the rear surface) of the electronic apparatus  100 , so that the first area  151 F is reduced and the second area  151 R is increased. 
     The frame part may support the flexible display  151  based on the change in shape of the flexible display  151 . As illustrated in  FIGS.  2 A through  3 B , the first frame  210  may support at least a portion of the first area  151 F and the second frame  220  may support the second area  151 R. Also, in a state in the first area  151 F is reduced, the first frame  210  and the second frame  220  may be located such that significant portions thereof overlap each other. 
     Meanwhile, a rear cover  230  may be attached to the second surface (e.g., the rear surface) of the electronic apparatus  100 . The rear cover  230  may be provided on the second surface of the electronic apparatus  100  and function as a cover that shields inside components of the electronic apparatus  100  not to be exposed outside. 
     At least a portion of the rear cover  230  may include a substantially transparent material, so that an image displayed in the second area  151 R is viewable from outside through the rear cover  230 . 
       FIG.  4    is an exploded perspective view illustrating an electronic apparatus according to an example embodiment of the present disclosure. 
     Referring to  FIG.  4   , the rear cover  230  may be attached to an outer surface of the frame part to cover at least a portion of the frame part (e.g., the first frame  210 , the second frame  220 ). 
     The rear cover  230  may be provided in a structure that is detachably attached to the outer surface of the frame part. 
     The rear cover  230  may be attached to one surface of the frame part that covers the third area  151 C of the flexible display  151 . In one example, as illustrated in  FIGS.  2 A through  3 B , when the third area  151 C is disposed inside the side surface portion of the second frame  220 , the rear cover  230  may be attached to one surface of the second frame  220  that forms the second surface of the electronic apparatus  100 . 
     In another example, although not shown, the third area  151 C may be disposed internal to the side surface portion of the first frame  210 . In this example, the rear cover  230  may be attached to one surface of the first frame  210  that forms the second surface of the electronic apparatus  100 . 
     The rear cover  230  may be coupled to an edge of the frame part adjacent to the third area  151 C on the second surface of the electronic apparatus  100 . 
     As illustrated in  FIG.  4   , at least a portion of the flexible display  151 , for example, the second area  151 R may be located between the rear cover  230  and the frame part to which the rear cover  230  is attached. The second area  151 R located between the rear cover  230  and the frame part may be increased or reduced in response to a change in position of the third area  151 C. 
     As described above, the change in shape (e.g., the increase or reduction of the first area  151 F or the second area  151 R) may repetitively occur in the flexible display  151 . Due to this, an external material (e.g., a foreign substance) may enter between the flexible display  151  and the frame part. 
     When the external material enters between the flexible display  151  and the frame part, inside components of the electronic apparatus  100  may be damaged by the external material. Thus, a structure for blocking an entry of the external material or easily discharging the external material to outside may be required in the electronic apparatus  100 . 
     The electronic apparatus  100  may use a structure in which the rear cover  230  is selectively detached from the frame part, to discharge the external material (e.g., the foreign substance) entering between the flexible display  151  and the frame part to outside. For example, based on an electrical signal, the electronic apparatus  100  may attach the rear cover  230  to the frame part or detach the rear cover  230  from the frame part. Hereinafter, an attachment and detachment method of the rear cover  230  will be described in detail. 
       FIG.  5    is a cross-sectional view illustrating an internal structure of an electronic apparatus according to an example embodiment of the present disclosure.  FIGS.  6 A through  6 C  are views illustrating a configuration of a coupling member according to an example embodiment of the present disclosure. 
     For example,  FIG.  5    illustrates the electronic apparatus  100  in which the rear cover  230  is detached or separated from the frame part (e.g., the second frame  220 ). 
     Referring to  FIGS.  5  through  6 C , the electronic apparatus  100  may include a coupling member to selectively attach or detach the rear cover  230  to or from the frame part. 
     For example, at least one coupling member (e.g., a first element  310 , a second element  330 , and a third element  320 ) may be arranged in a side portion of the frame part based on a position to which the rear cover  230  is attached. 
     The coupling member may be disposed for each edge or at least one edge of a surface to which the rear cover  230  is attached. For example, as illustrated in  FIG.  5   , the coupling member (e.g., the first element  310 , the second element  330 , and the third element  320 ) may be disposed at each of a top edge and a bottom edge based on the second surface (e.g., the rear surface) of the electronic apparatus  100 . 
     The coupling member may couple the rear cover  230  to the frame part or decouple the rear cover  230  from the frame part based on an electrical signal. 
     The coupling member may include the first element  310 , the second element  330 , and the third element  320 . 
     The first element  310  may be extended or contracted based on an electrical signal. The first element  310  may be formed using, for example, a shape memory alloy material. 
     For example, the first element  310  may have a shape of a wire. The first element  310  may contract in accordance with a temperature change (e.g., an increase of a temperature) occurring when an electrical signal is received. Also, the first element  310  may be extended when the receiving of the electrical signal is released. As such, a length of the wire may be changed. 
     Both end portions of the first element  310  may be fixed to the frame part. For example, both end portions of the first element  310  may be fixed to first protrusions  226  provided on one surface of the frame part. Also, the first element  310  may be supported by second protrusions  224  (refer to  FIG.  5   ) provided on one surface of the frame part so as to be maintained in a constant shape. 
     The first element  310  may correspond to a component for controlling a position of the second element  330 . For example, based on whether an electrical signal is received to the first element  310 , the second element  330  may move in one direction in response to the first element  310  being contracted or extended, thereby changing in position. For this, the second element  330  may be connected with the first element  310  to be changed in position based on a length change due to the extension and contraction of the first element  310 . As illustrated in  FIG.  6 A , the first element  310  may be disposed to penetrate a central hole  332  (refer to  FIG.  7 A ) of the second element  330  to be connected to the second element  330 . 
     Meanwhile, as illustrated in  FIG.  5   , at least two second elements  330  may be connected to the first element  310 . The second element  330  may be a component directly coupled to or decoupled from the frame part. When the second element  330  is provided in plurality, the rear cover  230  may be more stably mounted on the frame part. 
     As described above, when an electrical signal is received, the first element  310  may longitudinally contract and a contractile force may be exerted on both end portions of the first element  310  in a direction in which a distance therebetween increases (refer to  FIG.  6 C ). 
     Accordingly, the at least one second element  330  connected to a middle side of the first element  310  may receive a force in a direction in which the first element  310  is tightened, so as to move in a first direction (e.g., +y direction of  FIG.  5   ). 
     The third element  320  may be in a form of a wire similar to the first element  310  and have both end portions fixed to the frame part. For example, the end portion of the third element  320  may be fixed to a third protrusion  228  (refer to  FIG.  5   ) provided on the frame part. 
     The third element  320  may be connected to the second element  330 . 
     For example, the third element  320  may partially restrict a movement of the second element  330  to prevent the second element  330  from excessively separating from a predetermined position in response to the first element  310  being contracted. 
     The third element  320  may be formed of a material having a relatively high elasticity. 
     For example, when the first element  310  contracts in response to the electrical signal being received and the second element  330  moves in the first direction (e.g., an upward direction of  FIG.  6 C ), the third element  320  connected with the second element  330  may be pressurized in the first direction and generate an elastically restoring force in a second direction (e.g., a downward direction of  FIG.  6 C ) opposite to the first direction. 
     Meanwhile, in response that the receiving of the electrical signal is released, the first element  310  may be extended so that a length is restored to a state before the contraction. In this case, the second element  330  may move in the second direction by the elastically restoring force generated by the third element  320 , and return to a position before the contraction of the first element  310  (refer to  FIG.  6 B ). 
     In other words, when the electrical signal is applied, the second element  330  may move in the first direction by a contractile force generated due to the contraction of the first element  310 . Also, when the applying of the electrical signal is released, the second element  330  may move in the second direction by the extension of the first element  310  and the elastically restoring force of the third element  320 . 
     As illustrated in  FIG.  6 A , the plurality of third elements  320  may be connected to the single second element  330 . The third elements  320  may be coupled to a plurality of grooves  334  (refer to  FIG.  7 A ) formed in the side portion of the second element  330 . For example, the third elements  320  may be connected or coupled to the second element  330  on one surface of the second element  330  facing the first direction, so as to prevent the second element  330  from moving in the first direction when the first element  310  is contracted or to generate a compressive restoring force in the second direction in response to the second element  330  moving in the first direction. 
       FIG.  7 A  is a view illustrating a position in which a second element is disposed according to an example embodiment of the present disclosure. 
     Referring to  FIG.  7 A , the frame part (e.g., the second frame  220 ) may further include a guide rail  221  on one surface of the frame part facing the rear cover  230  to correspond to a position of the second element  330 . 
     When the second element  330  moves by a force applied in a first direction or a second direction, the guide rail  221  may prevent the second element  330  from being deviated in a direction other than the first and second directions. 
     The electronic apparatus  100  may couple or attach the rear cover  230  to the frame part or decouple the rear cover  230  from the frame part based on a position of the second element  330  moved along the guide rail  221  in the first direction or the second direction. 
       FIG.  7 B  is a side sectional view illustrating an electronic apparatus in which the rear cover  230  is coupled with the frame part, and  FIG.  7 C  is a side sectional view illustrating the electronic apparatus in which the rear cover  230  is decoupled from the frame part. 
     Referring to  FIGS.  7 B and  7 C , when an electrical signal is received to the first element  310 , the second element  330  may move in a first direction (e.g., +y direction) in response to the first element  310  being contracted. Also, when the receiving of the electrical signal is released, the second element  330  may move in a second direction (e.g., −y direction) in response to the first element  310  being extended and an elastically restoring force by the third element  320  being exerted. 
     Meanwhile, the rear cover  230  may include a hook  232  to be coupled with the second element  330 , on one surface facing the frame part (e.g., the second frame  220 ). 
     In  FIG.  7 B , when the electrical signal is not received to the first element  310 , the second element  330  may couple the rear cover  230  to the frame part (e.g., the second frame  220 ) as a state of being engaged with the hook  232  in a +z-axial direction. 
     In  FIG.  7 C , when the electrical signal is received to the first element  310 , the second element  330  may move in a first direction (e.g., +y direction) and thus, disengaged from the hook  232  in the +z axis direction. Through this, the rear cover  230  may be decoupled from the frame part (e.g., the second frame  220 ) to be separated or deviated in the +z direction. 
     The electronic apparatus  100  may further include a pad  236  in an area in which the frame part contacts the rear cover  230  when the rear cover  230  is coupled to the frame part (e.g., the second frame  220 ). For example, the pad  236  may prevent the external material (e.g., the foreign substance) enters between the rear cover  230  and the frame part in a state in which the rear cover  230  is coupled with the frame part. 
       FIG.  8 A  illustrates a cross-sectional view of an electronic apparatus and an enlarged perspective view of a portion of the electronic apparatus according to an example embodiment.  FIG.  8 B  is a cross-sectional view illustrating the portion of the electronic apparatus of  FIG.  8 A . 
     The electronic apparatus  100  may include the flexible display  151  including the first area  151 F in which an image is displayed on the first surface (e.g., the front surface) of the electronic apparatus  100 , the second area  151 R in which an image is displayed on the second surface (e.g., the rear surface) of the electronic apparatus  100 , and the third area  151 C between the first area  151 F and the second area  151 R. 
     A position of the third area  151 C may be changeable. Based on a change in the third area  151 C, a size of the first area  151 F or the second area  151 R may be changed. 
     The electronic apparatus  100  may include a third frame that covers the third area  151 C. The third frame that covers the third area  151 C may be either the first frame  210  or the second frame  220 . For example, when the third area  151 C is disposed internal to the side surface portion of the second frame  220 , the third frame may correspond to the second frame  220  as illustrated in  FIG.  8 A . 
     Referring to  FIGS.  8 A and  8 B , the electronic apparatus  100  may include at least one structure (e.g., a first structure  410  and a second structure  420 ) between the flexible display  151  and the third frame (e.g., the second frame  220 ) to block an inflow of an external material (e.g., a foreign substance). 
     For example, to block an external material entering between the first area  151 F and the third frame, the first structure  410  may have a pin shape in which one end is fixed to the third frame and the other end extends toward the first area  151 F. The first structure  410  may shield a space between the first area  151 F and the third frame. 
       FIGS.  9 A and  9 B  are views illustrating a first structure according to example embodiments of the present disclosure. 
     Referring to  FIG.  9 A , the first structure  410  may have an undercut shape (or an inversed tapered shape)  412  at one surface facing the flexible display  151 . In this case, the first structure  410  may be formed of at least one of thermoplastic polyurethane (TPU) or thermoplastic elastomer (TPE). The hardness of the first structure  410  may be, for example, about 40 to 60. 
     Referring to  FIG.  9 B , the first structure  410  may have a pattern of protrusions  414  on one surface facing the flexible display  151 . The first structure  410  may be formed of a silicone material. 
     As described above, a structure for minimizing an area contacting the flexible display  151  may be applied to the first structure  410 , thereby preventing a shape distortion due to a friction with the flexible display  151 . 
     For example, the second structure  420  may be disposed between the second area  151 R and the third frame to face the flexible display  151  in a tangential direction. 
     The second structure  420  may be a component for preventing the external material entering between the flexible display  151  (e.g., the third area  151 C) and the third frame (e.g., the second frame  220 ) from moving to the second area  151 R. 
     Meanwhile, the external material may be blocked not to move to the second area  151 R and thus, discharged to outside through an outlet on one side of the third frame. 
     For example, the outlet may be covered by a frame cover  430 . The frame cover  430  may be provided as a structure to be detachably coupled to the third frame. 
       FIGS.  10 A through  100    are views illustrating a structure for discharging a foreign substance according to example embodiments of the present disclosure. 
     Referring to  FIG.  10 A , an external material (e.g., a foreign substance) entering between the flexible display  151  and the third frame may be blocked by the second structure  420  not to move to the second area  151 R, and accumulated in a vicinity of an outlet near the second structure  420 . 
     As illustrated in  FIG.  10 B , the accumulated external material (e.g., the foreign substance) may be discharged to outside when the frame cover  430  is detached from the third frame (e.g., the second frame  220 ). 
     In another example embodiment, the frame cover  430  may be formed of a mesh-type material instead of being provided as a structure detachably coupled to the third frame. 
     In another example embodiment, a second structure may include a third structure  440  provided in a shape of a roller to be rotatable in one direction as illustrated in  FIG.  100   . 
     For example, the third structure  440  may be formed of a material that absorbs the external material (e.g., the foreign substance) entering between the third area  151 C and the third frame. The third structure  440  may absorb the external material and move the external material toward the outlet of the third frame. When the frame cover  430  that is provided as a detachable structure and covers the outlet is detached from the third frame, the third structure  440  may discharge the external material to outside. 
     When the electronic apparatus  100  includes the third structure  440 , a fourth structure  450  may be additionally provided between the flexible display  151  and the third frame (e.g., the second frame  220 ) to prevent the external material moved by the third structure  440  toward the outlet from moving to a space between the third area  151 C and the third frame. 
     According to example embodiments, an electronic apparatus may selectively increase or reduce an image display area on a front surface or a rear surface using a flexible display. Therefore, it is possible to easily carry the electronic apparatus and selectively use a large size display. 
     Further, according to example embodiments, an electronic apparatus may minimize an inflow of an external material (e.g., a foreign substance) due to a change in shape of a flexible display and, even when the external material enters, easily discharge the external material. Through this, it is possible to prevent a damage (e.g., a scratch on a display, etc.) of the electronic apparatus due to the external material. 
     Although exemplary embodiments of the present disclosure have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions, and substitutions are possible, without departing from the essential characteristics of the disclosure. Therefore, exemplary embodiments of the present disclosure have been described for the sake of brevity and clarity. Accordingly, those skilled in the art will understand the scope of the disclosure is not limited by the explicitly described above embodiments but by the claims and equivalents thereof.