Patent Publication Number: US-2022217859-A1

Title: Electronic device including hinge structure

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation application, claiming priority under § 365(c), of an International application No. PCT/KR2021/018437, filed on Dec. 7, 2021, which is based on and claims the benefit of a Korean patent application number 10-2021-0000859, filed on Jan. 5, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     1. Field 
     The disclosure relates to an electronic device including a hinge structure. 
     2. Description of Related Art 
     A portable electronic device such as a smartphone may provide various functions, such as telephone call, video playback, and Internet search, based on various types of applications. A user may want to use the aforementioned various functions through a wider screen. However, portability may be deteriorated with an increase in the size of the screen of the portable electronic device. Accordingly, a foldable electronic device including a flexible display, a partial area of which is deformable to be curved or flat, is being developed. The foldable electronic device may include a hinge structure to fold or unfold the flexible display. 
     The hinge structure of the foldable electronic device may be connected with adjacent housings such that the adjacent housings rotate at a predetermined angle. As the adjacent housings rotate, the flexible display may be unfolded or folded. 
     The above information is presented as background information only to assist with an understanding of the disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure. 
     SUMMARY 
     The foldable electronic device may include the flexible display, at least a partial area (e.g., a folding area) of which is deformable to be curved or flat. When the electronic device is folded, a fold (or crease) may occur in the folding area if the curvature of the folding area is large. Furthermore, when the electronic device is folded, a gap may occur between the housings if the curvature of the folding area is small. 
     Aspects of the disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the disclosure is to provide a hinge structure including a structure supporting a display to substantially completely close a housing while reducing damage to the display when an electronic device is in a folded state. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. 
     In accordance with an aspect of the disclosure, an electronic device is provided. The electronic device includes a housing including a first housing and a second housing, a display that extends from the first housing to the second housing, and a hinge structure that rotatably connects the first housing and the second housing. The hinge structure includes a fixed member, a first rotary member coupled to the fixed member so as to be rotatable about a first axis of rotation and connected with the first housing, the first axis of rotation extending parallel to an axial direction, a second rotary member coupled to the fixed member so as to be rotatable about a second axis of rotation parallel to the axial direction and connected with the second housing, a first guide member coupled to the first rotary member so as to be rotatable about a third axis of rotation parallel to the first axis of rotation, a second guide member coupled to the second rotary member so as to be rotatable about a fourth axis of rotation parallel to the second axis of rotation, a first rotary plate that is at least partially coupled to the first guide member to rotate about the third axis of rotation together with the first guide member and that supports a partial area of the display, and a second rotary plate that is at least partially coupled to the second guide member to rotate about the fourth axis of rotation together with the second guide member and that supports another partial area of the display. The hinge structure is configured such that when the first housing and/or the second housing is folded or unfolded, the first rotary member rotates about the first axis of rotation in a first rotational direction, the first guide member and the first rotary plate rotate about the third axis of rotation in the first rotational direction, the second rotary member rotates about the second axis of rotation in a second rotational direction opposite to the first rotational direction, and the second guide member and the second rotary plate rotate about the fourth axis of rotation in the second rotational direction. 
     In accordance with another aspect of the disclosure, an electronic device is provided. The electronic device includes a housing including a first housing and a second housing, a display that extends from the first housing to the second housing, and a hinge structure that rotatably connects the first housing and the second housing. The hinge structure includes a fixed member, a first rotary member that is coupled to the fixed member so as to be rotatable about a first axis of rotation parallel to an axial direction and connected with the first housing and that includes a first guide protrusion, a second rotary member that is coupled to the fixed member so as to be rotatable about a second axis of rotation parallel to the axial direction and connected with the second housing and that includes a second guide protrusion, a first arm shaft rotatably coupled to the fixed member and parallel to the axial direction, a second arm shaft rotatably coupled to the fixed member and parallel to the axial direction, a first arm that is coupled to the first arm shaft and that rotates together with the first arm shaft, the first arm including a first cam that surrounds the first arm shaft, a second arm that is coupled to the second arm shaft and that rotates together with the second arm shaft, the second arm including a second cam that surrounds the second arm shaft, a cam member coupled to the first arm shaft and the second arm shaft and linearly movable in the axial direction, the cam member including a third cam engaged with the first cam and a fourth cam engaged with the second cam, a first elastic member that is coupled to the first arm shaft and that provides an elastic force to the cam member in the axial direction, a second elastic member that is coupled to the second arm shaft and that provides an elastic force to the cam member in the axial direction, a first guide member that is coupled to the first rotary member so as to be rotatable about a third axis of rotation parallel to the first axis of rotation and that includes a first guide groove having an arc shape in which the first guide protrusion is accommodated, the third axis of rotation being defined as the center of the arc of the first guide groove, a second guide member that is coupled to the second rotary member so as to be rotatable about a fourth axis of rotation parallel to the second axis of rotation and that includes a second guide groove having an arc shape in which the second guide protrusion is accommodated, the fourth axis of rotation being defined as the center of the arc of the second guide groove, a first rotary plate that is coupled to the first guide member to rotate together with the first guide member and that supports a partial area of the display, and a second rotary plate that is coupled to the second guide member to rotate together with the second guide member and that supports another partial area of the display. The first guide member and the second guide member rotate relative to the first rotary member and the second rotary member as the first rotary member and the second rotary member rotate. When viewed in the axial direction, each of the third axis of rotation and the fourth axis of rotation overlaps at least a partial area of the display. 
     According to the various embodiments of the disclosure, when the electronic device is in a folded state, the display may be supported to form a specified shape (e.g., a water-drop shape). Accordingly, the curvature of the folding area may be made small, and a fold in the folding area may be decreased. 
     Furthermore, according to the various embodiments of the disclosure, when the electronic device is in a folded state, the first housing and the second housing may be substantially completely brought into close contact with each other. Accordingly, the exterior aesthetics may be improved. 
     Moreover, according to the various embodiments of the disclosure, the adhesive area of the display of the electronic device may be formed to be large. Accordingly, the surface quality and/or smoothness of the display may be improved. 
     In addition, the disclosure may provide various effects that are directly or indirectly recognized. 
     Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an exploded perspective view of an electronic device according to an embodiment of the disclosure; 
         FIG. 2A  is a view illustrating an unfolded state of an electronic device according to an embodiment of the disclosure; 
         FIG. 2B  is a view illustrating an intermediate folded state of an electronic device according to an embodiment of the disclosure; 
         FIG. 2C  is a view illustrating a fully folded state of an electronic device according to an embodiment of the disclosure; 
         FIG. 3  is a view illustrating part of an electronic device according to an embodiment of the disclosure; 
         FIG. 4  is a view illustrating a hinge structure according to an embodiment of the disclosure; 
         FIG. 5  is a view illustrating a hinge structure according to an embodiment of the disclosure; 
         FIG. 6  is a view illustrating a hinge structure according to an embodiment of the disclosure; 
         FIG. 7  is a view illustrating a coupling structure of housings, rotary members, and a fixed member of an electronic device according to an embodiment of the disclosure; 
         FIG. 8  is a view illustrating a coupling structure of rotary members, arm shafts, and arms of a hinge structure according to an embodiment of the disclosure; 
         FIG. 9A  is a view illustrating a coupling structure of rotary members, arm shafts, and arms of a hinge structure according to an embodiment of the disclosure; 
         FIG. 9B  is a view illustrating a coupling structure of rotary members, arm shafts, and arms of a hinge structure according to an embodiment of the disclosure; 
         FIG. 10A  is a view illustrating a cam member of a hinge structure according to an embodiment of the disclosure; 
         FIG. 10B  is a view illustrating a coupling structure of arm shafts and a cam member of the hinge structure according to an embodiment of the disclosure; 
         FIG. 10C  is a view illustrating a coupling structure of arm shafts and a cam member of a hinge structure according to an embodiment of the disclosure; 
         FIG. 11A  is a view illustrating a hinge structure and a display in an unfolded state of an electronic device according to an embodiment of the disclosure; 
         FIG. 11B  is a view illustrating a hinge structure and the display in a fully folded state of an electronic device according to an embodiment of the disclosure; 
         FIG. 12  is a view illustrating a folding motion of a hinge structure and a display according to an embodiment of the disclosure; 
         FIG. 13  is a view illustrating a rotary member of a hinge structure according to an embodiment of the disclosure; 
         FIG. 14  is a view illustrating a guide member of a hinge structure according to an embodiment of the disclosure; 
         FIG. 15  is a view illustrating a coupling structure of a rotary member and a guide member of a hinge structure according to an embodiment of the disclosure; 
         FIG. 16A  is a view illustrating a coupling structure of guide members and rotary plates of a hinge structure according to an embodiment of the disclosure; 
         FIG. 16B  is a view illustrating a coupling structure of guide members and rotary plates of a hinge structure according to an embodiment of the disclosure; 
         FIG. 17  is a view illustrating folding axes of a display of an electronic device according to an embodiment of the disclosure; 
         FIG. 18A  is a view illustrating the display, rotary members, guide members, and rotary plates of an electronic device according to an embodiment of the disclosure; 
         FIG. 18B  is a view illustrating a display, rotary members, guide members, and rotary plates of an electronic device according to an embodiment of the disclosure; 
         FIG. 19  is a view illustrating a rotary motion of guide members of a hinge structure according to an embodiment of the disclosure; 
         FIG. 20  is a view illustrating axes of rotation of guide members and rotary plates of a hinge structure according to an embodiment of the disclosure; 
         FIG. 21A  is a view illustrating adhesive areas and non-adhesive areas of a display of an electronic device according to an embodiment of the disclosure; 
         FIG. 21B  is a view illustrating adhesive areas and non-adhesive areas of a display of an electronic device according to an embodiment of the disclosure; 
         FIG. 22  is a view illustrating a display and a guide member of an electronic device according to an embodiment of the disclosure; 
         FIG. 23  is a view illustrating fixed plates of a hinge structure according to an embodiment of the disclosure; 
         FIG. 24A  is a view illustrating magnets of an electronic device and a motion of rotary plates using magnets according to an embodiment of the disclosure; 
         FIG. 24B  is a view illustrating magnets of an electronic device and a motion of rotary plates using the magnets according to an embodiment of the disclosure; 
         FIG. 25  is a view illustrating reinforcing plates of an electronic device according to an embodiment of the disclosure; 
         FIG. 26A  is a view illustrating a display and reinforcing plates of an electronic device according to an embodiment of the disclosure; and 
         FIG. 26B  is a view illustrating a display and reinforcing plates of an electronic device according to an embodiment of the disclosure. 
     
    
    
     Throughout the drawings, it should be noted that like reference numerals are used to depict the same or similar elements, features, and structures. 
     DETAILED DESCRIPTION 
     The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications, of the various embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. 
     The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purpose only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents. 
     It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
       FIG. 1  is an exploded perspective view of an electronic device according to an embodiment of the disclosure. 
     Referring to  FIG. 1 , the electronic device  100  according to an embodiment may include a first housing  110 , a second housing  120 , a hinge housing  130 , a display  140 , and a hinge structure  200 . 
     In an embodiment, the first housing  110  may be connected with the second housing  120  using the hinge structure  200 . The first housing  110  may include a first plate  111  on which the display  140  is seated and a first frame  112  surrounding at least part of the first plate  111 . For example, the first frame  112  may form a part of surfaces (e.g., side surfaces) of the electronic device  100 . For example, at least a portion of a first area  141  of the display  140  and at least a portion of a folding area  143  of the display  140  may be disposed on the first plate  111 . A first rotary member  220  of the hinge structure  200  may be connected to the first plate  111 . 
     In an embodiment, at least part of the first housing  110  may be attached with the first area  141  of the display  140 . Alternatively, part of the periphery of the front surface of the first housing  110  may be attached with the periphery of the first area  141  of the display  140 . In this regard, an adhesive layer may be disposed between the first plate  111  of the first housing  110  and the first area  141  of the display  140 . 
     In an embodiment, at least part of the inside of the first housing  110  may be provided in a hollow form. A first circuit board  151 , a first battery  153 , and a camera module  156  may be disposed in the first housing  110 . The first circuit board  151  and the first battery  153  may be electrically connected with a second circuit board  152  and a second battery  154  disposed in the second housing  120  through a flexible circuit board (not illustrated). For example, the flexible circuit board (not illustrated) may extend from a partial area of the first housing  110  to a partial area of the second housing  120  across the hinge housing  130 . A partial area of the flexible circuit board (not illustrated) may be located in the hinge housing  130 . For example, a processor and a memory may be disposed on the first circuit board  151 . For example, the first battery  153  and the first circuit board  151  may be disposed on the first plate  111 . 
     In an embodiment, at least part of the first housing  110  may be formed of a metallic material, or at least part of the first housing  110  may be formed of a non-metallic material. To support at least part of the display  140 , the first housing  110  may be formed of a material having a predetermined rigidity. In an embodiment, a portion of the first housing  110  that faces the second housing  120  may include a depression, at least part of which has a predetermined curvature such that the hinge housing  130  is disposed therein. 
     In various embodiments, the first housing  110  may include a first decorative member  113  surrounding the periphery of the display  140  and a first back cover  119  facing the first plate  111  and forming a surface of the electronic device  100 . For example, the first decorative member  113  may be disposed to cover the peripheral portion of the first area  141  of the display  140  and the periphery of part of the folding area  143 . For example, in an unfolded state (e.g., refer to  FIG. 2A ), the first back cover  119  may form the rear surface of the electronic device  100 , and the display  140  may form the front surface of the electronic device. 
     In an embodiment, the second housing  120  may be connected with the first housing  110  through the hinge structure  200 . The second housing  120  may include a second plate  121  on which the display  140  is seated and a second frame  122  surrounding at least part of the second plate  121 . For example, the second frame  122  may form a part of the surfaces (e.g., the side surfaces) of the electronic device  100 . For example, at least a portion of a second area  142  and at least part of the folding area  143  may be disposed on the second plate  121 . A second rotary member  230  of the hinge structure  200  may be connected to the second plate  121 . 
     In an embodiment, at least part of the second housing  120  may be attached with the second area  142  of the display  140 . Alternatively, part of the periphery of the front surface of the second housing  120  may be attached with the periphery of the second area  142  of the display  140 . In this regard, an adhesive layer may be disposed between the second plate  121  of the second housing  120  and the second area  142  of the display  140 . 
     In an embodiment, at least part of the inside of the second housing  120  may be provided in a hollow form. The second circuit board  152  and the second battery  154  may be disposed in the second housing  120 . The second circuit board  152  and the second battery  154  may be electrically connected with the first circuit board  151  and/or the first battery  153  disposed in the first housing  110  through the flexible circuit board (not illustrated). For example, the second battery  154  and the second circuit board  152  may be disposed on the second plate  121 . 
     In an embodiment, at least part of the second housing  120  may be formed of a metallic material, or at least part of the second housing  120  may be formed of a non-metallic material. To support at least part of the display  140 , the second housing  120  may be formed of a material having a predetermined rigidity. In an embodiment, a portion of the second housing  120  that faces the first housing  110  may include a depression, at least part of which has a predetermined curvature such that the hinge housing  130  is disposed therein. 
     In various embodiments, the second housing  120  may include a second decorative member  123  surrounding the periphery of the display  140  and a second back cover  129  facing the second plate  121  and forming a surface of the electronic device  100 . For example, the second decorative member  123  may be disposed to cover the peripheral portion of the second area  142  of the display  140  and the periphery of part of the folding area  143 . For example, in an unfolded state (e.g., refer to  FIG. 2A ), the second back cover  129  may form the rear surface of the electronic device  100 , and the display  140  may form the front surface of the electronic device. 
     In various embodiments, the electronic device  100  may further include a lattice structure (not illustrated) (e.g., reinforcing plates  194  and  195  of  FIGS. 25, 26A , and  26 B) and/or a bracket (not illustrated) disposed between the display  140  and the adhesive layers. The lattice structure may include a slit area including a plurality of slits at least partially overlapping the folding area  143 . The plurality of slits may extend in the extension direction (e.g., the y-axis) of the folding area  143 . The plurality of slits may support the folding area  143  that is flat in an unfolded state (e.g., refer to  FIG. 2A ) and may support deformation of the folding area  143  in a folding motion or an unfolding motion. In various embodiments, only part of the lattice structure or the bracket may be stacked on the display  140 . 
     In an embodiment, the hinge housing  130  may be disposed in the depressions of the first housing  110  and the second housing  120 . The hinge housing  130  may have a form extending in the y-axis direction as a whole. Bosses for fixing the hinge structure  200  may be disposed on partial areas of the inside surface of the hinge housing  130 . 
     In an embodiment, at least part of the display  140  may have flexibility. For example, the display  140  may include the first area  141  disposed on the first housing  110 , the second area  142  disposed on the second housing  120 , and the folding area  143  located between the first area  141  and the second area  142 . In an embodiment, the first area  141  and the second area  142  may be formed to be flat, and the folding area  143  may be formed such that at least part thereof is deformable to be flat or curved. 
     According to various embodiments, the hinge structure  200  may include the first rotary member  220  connected to the first housing  110  and the second rotary member  230  connected to the second housing  120 . The hinge structure  200  may be configured such that the first rotary member  220  and the second rotary member  230  are rotatable about axes of rotation thereof (e.g., axes parallel to the y-axis direction). For example, when the first housing  110  and the second housing  120  are folded or unfolded, the first rotary member  220  and the second rotary member  230  may rotate about the axes of rotation thereof. 
       FIG. 2A  is a view illustrating an unfolded state of an electronic device according to an embodiment of the disclosure. 
       FIG. 2B  is a view illustrating an intermediate folded state of an electronic device according to an embodiment of the disclosure. 
       FIG. 2C  is a view illustrating a fully folded state of an electronic device according to an embodiment of the disclosure. 
     Referring to  FIGS. 2A, 2B, and 2C , the electronic device  100  according to an embodiment may be configured such that the first housing  110  and the second housing  120  rotate about axes of rotation R 1  and R 2  in opposite directions. For example, in a folding motion performed in the unfolded state (the state of  FIG. 2A ), based on the drawing, the first housing  110  may rotate in the counterclockwise direction, and the second housing  120  may rotate in the clockwise direction. 
     In an embodiment, an axial direction parallel to the axes of rotation of the first housing  110  and the second housing  120  may be defined. The axial direction may be defined as the extension direction of the folding area  143  of the display  140 . For example, the axial direction may be defined as the direction of the long sides of the folding area  143 . For example, the axial direction may refer to the direction parallel to the y-axis. 
     To describe a state of the electronic device  100  according to an embodiment of the disclosure, a first edge P 1  of the electronic device  100  and a second edge P 2  of the electronic device  100  that are parallel to the axial direction may be defined. To describe a state of the electronic device  100 , a third edge P 3  of the electronic device  100  and a fourth edge P 4  of the electronic device  100  that are perpendicular to the axial direction may be defined. For example, the first edge P 1  and the third edge P 3  may include part of the first frame (e.g., the first frame  112  of  FIG. 1 ) of the first housing  110 . For example, the second edge P 2  and the fourth edge P 4  may include part of the second frame (e.g., the second frame  122  of  FIG. 1 ) of the second housing  120 . 
     The unfolded state of the electronic device  100  will be described below with reference to  FIG. 2A . 
     For example, the unfolded state may include the state in which the folding area  143  of the display  140  is flat. For example, the unfolded state may include the state in which the first area  141  and the second area  142  of the display  140  face the same direction. For example, the unfolded state may include the state in which a first normal vector n 1  of the first area  141  and a second normal vector n 2  of the second area  142  of the display  140  are parallel to each other. For example, the unfolded state may include the state in which the third edge P 3  and the fourth edge P 4  form substantially one straight line. For example, the unfolded state may include the state in which the third edge P 3  and the fourth edge P 4  form an angle of 180 degrees. 
     The intermediate folded state of the electronic device  100  will be described below with reference to  FIG. 2B . 
     For example, the intermediate folded state (or, the intermediate state) may include the state in which the folding area  143  of the display  140  is curved. For example, the intermediate folded state may include the state in which the first normal vector n 1  of the first area  141  and the second normal vector n 2  of the second area  142  form a certain angle rather than 180 degrees. For example, the intermediate folded state may include the state in which the third edge P 3  and the fourth edge P 4  form a certain angle rather than 180 degrees. 
     The substantially fully folded state of the electronic device  100  will be described below with reference to  FIG. 2C . 
     For example, the substantially fully folded state may refer to the state in which the first edge P 1  and the second edge P 2  substantially make contact with each other, among folded states. For example, the substantially fully folded state may refer to the state in which the third edge P 3  and the fourth edge P 4  substantially make contact with each other. For example, in the substantially fully folded state, the third edge P 3  and the fourth edge P 4  may face each other in parallel. For example, the substantially fully folded state may include the state in which the third edge P 3  and the fourth edge P 4  form an angle of about 0 degrees. For example, the folding area  143  in the substantially fully folded state may be curved with a curvature greater than that of the folding area  143  in the intermediate folded state. 
     In various embodiments, the intermediate folded state of the electronic device  100  may be construed as including any states defined between the unfolded state and the substantially fully folded state. For example, the intermediate folded state may include states in which the included angle between the third edge P 3  and the fourth edge P 4  is more than 0 degrees and less than 180 degrees. 
     Referring to  FIGS. 2B and 2C , in the intermediate folded state and the fully folded state, at least part of the hinge housing  130  may form the exterior (or, a surface) of the electronic device  100 . For example, the hinge housing  130  may be visually exposed between the first housing  110  and the second housing  120  when the electronic device  100  is in the intermediate folded state or the fully folded state. 
       FIG. 3  is a view illustrating part of an electronic device according to an embodiment of the disclosure. 
     Referring to  FIG. 3 , the electronic device  100  according to an embodiment may include the first housing  110 , the second housing  120 , and the hinge structure  200 . The hinge structure  200  may rotatably connect the first housing  110  and the second housing  120 . 
       FIG. 3  may be a view in which the display  140  is omitted from the electronic device  100  of  FIG. 1  to represent a coupling structure between the housings  110  and  120  and the hinge structure  200 . 
     In an embodiment, the hinge structure  200  may include a fixed member  210 , the first rotary member  220 , the second rotary member  230 , a first rotary plate  261 , a second rotary plate  262 , a first fixed plate  263 , and a second fixed plate  264 . 
     In an embodiment, the fixed member  210  may be fixed between the first housing  110  and the second housing  120 . For example, the fixed member  210  may be fixedly disposed in the hinge housing (e.g., the hinge housing  130  of  FIGS. 1, 2B, and 2C ) that is disposed in the depressions of the first housing  110  and the second housing  120 . The first rotary member  220  and the second rotary member  230  may be coupled to the fixed member  210  so as to be rotatable about the axes of rotation R 1  and R 2 . 
     In an embodiment, the first rotary member  220  may be coupled to the fixed member  210  so as to be rotatable about the first axis of rotation R 1 . The first rotary member  220  may be connected to the first plate  111  to rotate together with the first housing  110 . For example, when the electronic device  100  is folded or unfolded, the first rotary member  220  may rotate about the first axis of rotation R 1  together with the first housing  110 . 
     In an embodiment, the second rotary member  230  may be coupled to the fixed member  210  so as to be rotatable about the second axis of rotation R 2 . The second rotary member  230  may be connected to the second plate  121  to rotate together with the second housing  120 . For example, when the electronic device  100  is folded or unfolded, the second rotary member  230  may rotate about the second axis of rotation R 2  together with the second housing  120 . 
     In an embodiment, the first axis of rotation R 1  of the first rotary member  220  and the second axis of rotation R 2  of the second rotary member  230  may be parallel to each other. For example, part of the first rotary member  220  may be rotatably coupled to part of the fixed member  210  by a connecting member (or, a rivet) (e.g., a first connecting shaft  211  of  FIGS. 4 to 7 ), and the first axis of rotation R 1  may be formed by the connecting member. For example, part of the second rotary member  230  may be rotatably coupled to another part of the fixed member  210  by a connecting member (e.g., a second connecting shaft  212  of  FIGS. 4 to 7 ), and the second axis of rotation R 2  may be formed by the connecting member. 
     In an embodiment, the first rotary plate  261  may be connected to the first rotary member  220 . For example, the first rotary plate  261  may be connected so as to be rotatable relative to the first rotary member  220 . The first rotary plate  261  may support at least a partial area of the display (e.g., the display  140  of  FIG. 1 ). For example, when the electronic device  100  is folded or unfolded, the first rotary plate  261  may support the display  140  while rotating relative to the first rotary member  220 . Although not illustrated, the first rotary plate  261  may be configured to rotate about a virtual third axis of rotation (not illustrated) relative to the first rotary member  220 . For example, the virtual third axis of rotation may be parallel to the first axis of rotation R 1  and may be spaced apart from the first axis of rotation R 1  in a direction (e.g., the −x-axis direction) toward the first plate  111  when the first plate  111  is viewed from above. 
     In an embodiment, the second rotary plate  262  may be connected to the second rotary member  230 . For example, the second rotary plate  262  may be connected so as to be rotatable relative to the second rotary member  230 . The second rotary plate  262  may support at least a partial area of the display  140 . For example, when the electronic device  100  is folded or unfolded, the second rotary plate  262  may support the display  140  while rotating relative to the second rotary member  230 . Although not illustrated, the second rotary plate  262  may be configured to rotate about a virtual fourth axis of rotation (not illustrated) relative to the second rotary member  230 . For example, the virtual fourth axis of rotation may be parallel to the second axis of rotation R 2  and may be spaced apart from the second axis of rotation R 2  in a direction (e.g., the +x-axis direction) toward the second plate  121  when the second plate  121  is viewed from above. 
     In an embodiment, the first fixed plate  263  may be coupled to a partial area of the first plate  111  of the first housing  110 . The first fixed plate  263  may form substantially the same plane as the first plate  111 . For example, the first fixed plate  263 , together with the first plate  111  and the first rotary plate  261 , may support a partial area (e.g., the first area  141 ) of the display  140 . For example, at least part of the display  140  may be attached to the first fixed plate  263 . For example, an adhesive layer (not illustrated) may be disposed between a partial area of the display  140  and the first fixed plate  263 . 
     In an embodiment, the second fixed plate  264  may be coupled to a partial area of the second plate  121  of the second housing  120 . The second fixed plate  264  may form substantially the same plane as the second plate  121 . For example, the second fixed plate  264 , together with the second plate  121  and the second rotary plate  262 , may support a partial area (e.g., the second area  142 ) of the display  140 . For example, at least part of the display  140  may be attached to the second fixed plate  264 . For example, an adhesive layer (not illustrated) may be disposed between a partial area of the display  140  and the second fixed plate  264 . 
     In an embodiment, the electronic device  100  may be configured such that the frames  112  and  122  of the housings  110  and  120  protrude above the plates  111  and  121 . For example, the first frame  112  may protrude from the periphery of the first plate  111  to a specified height in a direction (e.g., the +z-axis direction) substantially perpendicular to the first plate  111 . For example, the second frame  122  may protrude from the periphery of the second plate  121  to a specified height in a direction (e.g., the +z-axis direction) substantially perpendicular to the second plate  121 . The first frame  112  and the second frame  122  may protrude above the display  140  when the display  140  is disposed on the first plate  111  and the second plate  121 . For example, when the first frame  112  and the second frame  122  make contact with each other in a fully folded state, the first plate  111  and the second plate  121  may be spaced apart from each other at a specified interval, and the display  140  may be configured such that the first area (e.g., the first area  141  of  FIG. 1 ) and the second area (e.g., the second area  142  of  FIG. 1 ) are spaced apart from each other. 
       FIG. 4  is a view illustrating a hinge structure according to an embodiment of the disclosure. 
       FIG. 5  is a view illustrating a hinge structure according to an embodiment of the disclosure. 
       FIG. 6  is a view illustrating a hinge structure according to an embodiment of the disclosure. 
     Referring to  FIGS. 4 to 6 , the hinge structure  200  according to an embodiment may include the fixed member  210 , the first rotary member  220 , the second rotary member  230 , an interlocking structure  201 , a friction structure  202 , a support structure  203 , the first fixed plate  263 , and the second fixed plate  264 . 
     As illustrated in  FIGS. 4 to 6 , axial directions may be defined in the hinge structure  200 . The axial directions may be parallel to the extension direction of the first axis of rotation R 1  and the second axis of rotation R 2 . A first axial direction {circle around ( 1 )} may a direction toward the fixed member  210 , and a second axial direction {circle around ( 2 )}  may be a direction opposite to the first axial direction {circle around ( 1 )} (or, a direction toward a shaft bracket  294 ). 
     In an embodiment, at least part of the fixed member  210  may be fixedly disposed in the hinge housing (e.g., the hinge housing  130  of  FIG. 1 ). The first rotary member  220  and the second rotary member  230  may be rotatably coupled to one portion (e.g., a first coupling portion  213 ) of the fixed member  210 . A first arm shaft  265  and a second arm shaft  266  may be rotatably coupled to another portion (e.g., a second coupling portion  214 ) of the fixed member  210 . 
     In an embodiment, the fixed member  210  may include the first coupling portion  213  to which the first rotary member  220  and the second rotary member  230  are coupled. For example, a first extension  221  of the first rotary member  220  may be rotatably coupled to part of the first coupling portion  213  through the first connecting shaft  211 . A second extension  231  of the second rotary member  230  may be rotatably coupled to another part of the first coupling portion  213  through the second connecting shaft  212 . 
     In an embodiment, the first coupling portion  213  of the fixed member  210  may have a first through-hole  216  formed therein into which the first connecting shaft  211  is inserted. The first through-hole  216  may be formed through a partial area of the first coupling portion  213  in the axial directions. The first connecting shaft  211  may be inserted into the first through-hole  216  of the first coupling portion  213  and a third through-hole  226  of the first rotary member  220  to rotatably couple the first rotary member  220  to the fixed member  210 . For example, the first connecting shaft  211  may be fixed to the fixed member  210 , or may be inserted into the first through-hole  216  so as to be rotatable. The first connecting shaft  211  may be fixed to the first rotary member  220 , or may be inserted into the third through-hole  226  so as to be rotatable. For example, the first connecting shaft  211  may include a rivet. 
     In an embodiment, the first coupling portion  213  of the fixed member  210  may have a second through-hole  217  formed therein into which the second connecting shaft  212  is inserted. The second through-hole  217  may be formed through a partial area of the first coupling portion  213  in the axial directions. For example, the second through-hole  217  may be spaced apart from the first through-hole  216  in a direction perpendicular to the axial directions. The second connecting shaft  212  may be inserted into the second through-hole  217  of the first coupling portion  213  and a fourth through-hole  236  of the second rotary member  230  to rotatably couple the second rotary member  230  to the fixed member  210 . For example, the second connecting shaft  212  may be fixed to the fixed member  210 , or may be inserted into the second through-hole  217  so as to be rotatable. The second connecting shaft  212  may be fixed to the second rotary member  230 , or may be inserted into the fourth through-hole  236  so as to be rotatable. For example, the second connecting shaft  212  may include various coupling members (or, fastening members) including a rivet, a bolt, or a pin. 
     In an embodiment, the fixed member  210  may include the second coupling portion  214  to which the first arm shaft  265  and the second arm shaft  266  are coupled. The second coupling portion  214  may face the first coupling portion  213  in the axial directions. The first arm shaft  265  and the second arm shaft  266  may be rotatably coupled to the second coupling portion  214 . For example, a first opening  218  may be formed in part of the second coupling portion  214 , and the first arm shaft  265  may be inserted into the first opening  218  so as to be rotatable. A second opening  219  may be formed in another part of the second coupling portion  214 , and the second arm shaft  266  may be inserted into the second opening  219  so as to be rotatable. In various embodiments, the openings  218  and  219  may be formed in a groove or hole shape such that at least parts of the arm shafts  265  and  266  are inserted into or accommodated in the openings  218  and  219 . 
     In an embodiment, the first rotary member  220  may be configured to rotate about the first axis of rotation R 1  relative to the fixed member  210 , which is fixed to the hinge housing  130 , when the first housing (e.g., the first housing  110  of  FIGS. 1, 2A, 2B, 2C, and 3 ) is folded or unfolded. For example, the first rotary member  220  may be coupled to the fixed member  210  through the first connecting shaft  211  and may rotate about the first connecting shaft  211  relative to the fixed member  210 . The first axis of rotation R 1  of the first rotary member  220  may be formed by the first connecting shaft  211 . For example, the first axis of rotation R 1  may be defined as a virtual straight line extending in the axial directions to pass through the center of the first connecting shaft  211 . 
     In an embodiment, the first rotary member  220  may include the first extension  221  rotatably coupled to the fixed member  210 . For example, the first extension  221  may have the third through-hole  226  formed therein into which the first connecting shaft  211  is inserted. In an embodiment, a first guide member  240  may be coupled to the first rotary member  220  so as to be rotatable along a predetermined path. The first rotary member  220  may include first guide protrusions  224  for guiding the rotational path of the first guide member  240 . For example, the first rotary member  220  may have a first opening area  223  formed therein in which the first guide member  240  is accommodated, and the first guide protrusions  224  may be formed on inside surfaces of the first opening area  223 . 
     In an embodiment, the second rotary member  230  may be configured to rotate about the second axis of rotation R 2  relative to the fixed member  210 , which is fixed to the hinge housing  130 , when the second housing (e.g., the second housing  120  of  FIGS. 1, 2A, 2B, 2C, and 3 ) is folded or unfolded. For example, the second rotary member  230  may be coupled to the fixed member  210  through the second connecting shaft  212  and may rotate about the second connecting shaft  212  relative to the fixed member  210 . The second axis of rotation R 2  of the second rotary member  230  may be formed by the second connecting shaft  212 . For example, the second axis of rotation R 2  may be defined as a virtual straight line extending in the axial directions to pass through the center of the second connecting shaft  212 . 
     In an embodiment, the second rotary member  230  may include the second extension  231  rotatably coupled to the fixed member  210 . For example, the second extension  231  may have the fourth through-hole  236  formed therein into which the second connecting shaft  212  is inserted. In an embodiment, a second guide member  250  may be coupled to the second rotary member  230  so as to be rotatable along a predetermined path. The second rotary member  230  may include second guide protrusions  234  for guiding the rotational path of the second guide member  250 . For example, the second rotary member  230  may have a second opening area  233  formed therein in which the second guide member  250  is accommodated, and the second guide protrusions  234  may be formed on inside surfaces of the second opening area  233 . 
     In an embodiment, the interlocking structure  201  may include the first arm shaft  265 , the second arm shaft  266 , a first arm  270 , a second arm  280 , a gear member  269 , the shaft bracket  294 , and a stopper  291 . For example, when the electronic device  100  is folded or unfolded, the interlocking structure  201  may interlock the first rotary member  220  and the second rotary member  230  such that the first rotary member  220  and the second rotary member  230  rotate in opposite directions by the same angle. 
     In an embodiment, the first arm shaft  265  may be rotatably coupled to the fixed member  210 . For example, at least part of one end portion (e.g., an end portion facing the first axial direction {circle around ( 1 )}) of the first arm shaft  265  may be rotatably coupled to the second coupling portion  214  of the fixed member  210 . For example, the end portion of the first arm shaft  265  that faces the first axial direction {circle around ( 1 )} may be rotatably inserted into the first opening  218  formed in the second coupling portion  214 . 
     In an embodiment, a first fixing ring  296   a  may be coupled to an opposite end portion (e.g., an end portion facing the second axial direction {circle around ( 2 )}) of the first arm shaft  265 . The first fixing ring  296   a  may fix the shaft bracket  294  such that the shaft bracket  294  is not separated from the first arm shaft  265  in the axial directions (e.g., the second axial direction {circle around ( 2 )}). A first support ring  259   a  may be coupled to the end portion of the first arm shaft  265  that faces the second axial direction {circle around ( 2 )}. The first support ring  295   a , together with the first arm shaft  265 , may rotate in the same direction as the rotational direction of the first arm shaft  265 , and in an unfolded state, the first support ring  295   a  may support a center bar  297 . For example, the fixed member  210 , the stopper  291 , the first arm  270 , a cam member  292 , a first elastic member  293   a , the shaft bracket  294 , the first support ring  295   a , and the first fixing ring  296   a  may be coupled to the first arm shaft  265  in the second axial direction {circle around ( 2 )}. 
     In an embodiment, the first arm  270  may be coupled to the first arm shaft  265  so as to rotate about the first arm shaft  265 . The first arm  270  may be coupled to the first rotary member  220  to rotate about the first arm shaft  265  while sliding relative to the first rotary member  220  when the first rotary member  220  rotates. For example, the first arm  270  may be slidably coupled to the first rotary member  220  through a first sliding pin  274 . For example, the first sliding pin  274  may be inserted into a first sliding groove  227  of the first rotary member  220  and a first pin hole  275  of the first arm  270  and may slidably connect the first arm  270  to the first rotary member  220 . 
     In an embodiment, the second arm shaft  266  may be rotatably coupled to the fixed member  210 . For example, at least part of one end portion (e.g., an end portion facing the first axial direction {circle around ( 1 )}) of the second arm shaft  266  may be rotatably coupled to the second coupling portion  214  of the fixed member  210 . For example, the end portion of the second arm shaft  266  that faces the first axial direction {circle around ( 1 )} may be rotatably inserted into the second opening  219  formed in the second coupling portion  214 . 
     In an embodiment, a second fixing ring  296   b  may be coupled to an opposite end portion (e.g., an end portion facing the second axial direction {circle around ( 2 )}) of the second arm shaft  266 . The second fixing ring  296   b  may fix the shaft bracket  294  such that the shaft bracket  294  is not separated from the second arm shaft  266  in the axial directions (e.g., the second axial direction {circle around ( 2 )}). A second support ring  295   b  may be coupled to the end portion of the second arm shaft  266  that faces the second axial direction {circle around ( 2 )}. The second support ring  295   b , together with the second arm shaft  266 , may rotate in the same direction as the rotational direction of the second arm shaft  266 , and in an unfolded state, the second support ring  295   b  may support the center bar  297  together with the first support ring  295   a.  For example, the fixed member  210 , the stopper  291 , the second arm  280 , the cam member  292 , a second elastic member  293   b , the shaft bracket  294 , the second support ring  295   b , and the second fixing ring  296   b  may be coupled to the second arm shaft  266  in the second axial direction {circle around ( 2 )}. 
     In an embodiment, the second arm  280  may be coupled to the second arm shaft  266  so as to rotate about the second arm shaft  266 . The second arm  280  may be coupled to the second rotary member  230  to rotate about the second arm shaft  266  while sliding relative to the second rotary member  230  when the second rotary member  230  rotates. For example, the second arm  280  may be slidably coupled to the second rotary member  230  through a second sliding pin  284 . For example, the second sliding pin  284  may be inserted into a second sliding groove  237  of the second rotary member  230  and a second pin hole  285  of the second arm  280  and may slidably connect the second arm  280  to the second rotary member  230 . 
     In an embodiment, the gear member  269  may include a first gear  267   a  disposed on the outer circumferential surface of the first arm shaft  265 , a second gear  267   b  disposed on the outer circumferential surface of the second arm shaft  266 , and a connecting gear  268  connecting the first gear  267   a  and the second gear  267   b  such that the first gear  267   a  and the second gear  267   b  operate in conjunction with each other. The gear member  269  may allow the first arm shaft  265  and the second arm shaft  266  to operate in conjunction with each other such that the first arm shaft  265  and the second arm shaft  266  rotate in opposite directions by the same angle. For example, when one of the first arm shaft  265  and the second arm shaft  266  rotates in a first direction by a first angle, the gear member  269  may rotate the other one of the first arm shaft  265  and the second arm shaft  266  in the direction opposite to the first direction by the first angle. For example, the connecting gear  268  may include an even number of gears for interworking between the first arm shaft  265  and the second arm shaft  266 . 
     In an embodiment, the shaft bracket  294  may be fixedly disposed in the hinge housing  130 . The shaft bracket  294  may be disposed on the end portions of the first arm shaft  265  and the second arm shaft  266  that face the second axial direction {circle around ( 2 )}. The shaft bracket  294  may be configured to support rotation of the first arm shaft  265  and the second arm shaft  266  together with the fixed member  210 . For example, the opposite end portions of each of the first arm shaft  265  and the second arm shaft  266  may be supported by the shaft bracket  294  and the second coupling portion  214 . 
     In an embodiment, the shaft bracket  294  may support an end portion of the first elastic member  293   a  and an end portion of the second elastic member  293   b  that face the second axial direction {circle around ( 2 )}. For example, as the end portions of the first elastic member  293   a  and the second elastic member  293   b  that face the second axial direction {circle around ( 2 )} are supported by the shaft bracket  294 , the first elastic member  293   a  and the second elastic member  293   b  may be compressed when pressed in the second axial direction {circle around ( 2 )}. In an embodiment, the shaft bracket  294  may have, in at least parts thereof, through-holes (not illustrated) into which the first arm shaft  265  and the second arm shaft  266  are inserted. 
     In an embodiment, the stopper  291  may be fixedly disposed in the hinge housing  130 . The stopper  291  may limit the range of rotation of the first arm  270  and the second arm  280 . For example, at least part of the stopper  291  may be located between the first arm  270  and the second arm  280 . In an embodiment, the stopper  291  may have, in at least parts thereof, through-holes (not illustrated) into which the first arm shaft  265  and the second arm shaft  266  are inserted. 
     In an embodiment, the friction structure  202  may be configured to provide torque corresponding to a restoring force of the display  140 . For example, in an intermediate folded state (e.g.,  FIG. 2B ) or a fully folded state (e.g.,  FIG. 2C ) in which a partial area of the display  140  is curved, the restoring force of the display  140  may act on the first rotary member  220  and the second rotary member  230 . For example, the restoring force of the display  140  may refer to a force by which a curved portion returns to a flat state. For example, the restoring force of the display  140  may be proportional to the size of the display  140 . The hinge structure  200  according to an embodiment may include the friction structure  202  that provides torque capable of canceling out the restoring force. 
     In an embodiment, the friction structure  202  may include a first cam  273 , a second cam  283 , the cam member  292 , the first elastic member  293   a , and the second elastic member  293   b.  The friction structure  202  according to an embodiment may be configured such that some of the structures coupled to the first arm shaft  265  and the second arm shaft  266  rotate together with the arm shafts  265  and  266  or linearly move in the axial directions along the arm shaft  265  and  266  and the other structures are fixed to the arm shafts  265  and  266  to provide torque. 
     For example, when the first arm shaft  265  rotates, the first arm  270  may rotate together with the first arm shaft  265  and may not linearly move in the axial directions. When the second arm shaft  266  rotates, the second arm  280  may rotate together with the second arm shaft  266  and may not linearly move in the axial directions. For example, the first arm  270  and the second arm  280  may rotate in the state in which the axial positions thereof on the first arm shaft  265  and the second arm shaft  266  are fixed. 
     For example, when the first arm shaft  265  and the second arm shaft  266  rotate, the cam member  292  may not rotate together with the first arm shaft  265  and the second arm shaft  266  and may linearly move in the axial directions along the first arm shaft  265  and the second arm shaft  266 . For example, when the first arm shaft  265  rotates, the first elastic member  293   a  may be compressed or uncompressed in the axial directions by the axial movement of the cam member  292 . When the second arm shaft  266  rotates, the second elastic member  293   b  may be compressed or uncompressed by the axial movement of the cam member  292 . 
     For example, when the first arm shaft  265  rotates, the first fixing ring  296   a  may not move in the axial directions and may or may not rotate together with the first arm shaft  265 . When the second arm shaft  266  rotates, the second fixing ring  296   b  may not move in the axial directions and may or may not rotate together with the second arm shaft  266 . For example, when the first arm shaft  265  rotates, the first support ring  295   a  may not move in the axial directions and may rotate together with the first arm shaft  265 . When the second arm shaft  266  rotates, the second support ring  295   b  may not move in the axial directions and may rotate together with the second arm shaft  266 . 
     In an embodiment, the first cam  273  may be formed on the first arm  270 . For example, the first cam  273  may be formed on the first arm  270  to surround the outer circumferential surface of the first arm shaft  265 . The first cam  273  may be engaged with a third cam  2921  of the cam member  292 . When the first arm shaft  265  rotates, the first cam  273  may not move in the axial directions and may rotate together with the first arm shaft  265 . For example, the first cam  273  may rotate relative to the third cam  2921  by rotation of the first arm shaft  265 . 
     In an embodiment, the second cam  283  may be formed on the second arm  280 . For example, the second cam  283  may be formed on the second aim  280  to surround the outer circumferential surface of the second arm shaft  266 . The second cam  283  may be engaged with a fourth cam  2922  of the cam member  292 . When the second arm shaft  266  rotates, the second cam  283  may not move in the axial directions and may rotate together with the second arm shaft  266 . For example, the second cam  283  may rotate relative to the fourth cam  2922  by rotation of the second arm shaft  266 . 
     In an embodiment, the cam member  292  may be configured such that the first arm shaft  265  and the second arm shaft  266  pass through at least parts of the cam member  292 . When the first arm shaft  265  and the second arm shaft  266  rotate, the cam member  292  may not rotate together with the arm shafts  265  and  266  and may move in the axial directions. 
     In an embodiment, the cam member  292  may include the third cam  2921  engaged with the first cam  273  of the first arm  270  and the fourth cam  2922  engaged with the second cam  283  of the second arm  280 . For example, the third cam  2921  may be formed on one portion (e.g., a first portion  292   a  of  FIGS. 10A, 10B, and 10C ) of the cam member  292  to surround the first arm shaft  265 . The fourth cam  2922  may be formed on another portion (e.g., a second portion  292   b  of  FIGS. 10A, 10B, and 10C ) of the cam member  292  to surround the second arm shaft  266 . 
     In an embodiment, the cam member  292  may compress the first elastic member  293   a  and the second elastic member  293   b  while moving in the second axial direction {circle around ( 2 )} by rotation of the first cam  273  and the second cam  283 , or may be compressed in the first axial direction {circle around ( 1 )} by elastic forces of the first elastic member  293   a  and the second elastic member  293   b.  For example, when the first cam  273  and the second cam  283  rotate relative to the third cam  2921  and the fourth cam  2922  in the state in which protrusions of the first cam  273  and the second cam  283  are located in depressions of the third cam  2921  and the fourth cam  2922 , the protrusions of the first cam  273  and the protrusions of the second cam  283  may make contact with protrusions of the third cam  2921  and protrusions of the fourth cam  2922 , respectively, to move the cam  292  in the second axial direction {circle around ( 2 )}. 
     In an embodiment, the first elastic member  293   a  may be disposed between the cam member  292  and the shaft bracket  294 . The first elastic member  293   a  may be coupled to the first arm shaft  265 . For example, the first elastic member  293   a  may include a coil spring that can be axially compressed or uncompressed. The first elastic member  293   a  may be compressed or uncompressed in response to rotation of the first arm  270 . For example, the first elastic member  293   a  may be compressed when the cam member  292  moves in the second axial direction {circle around ( 2 )}, and the compressed first elastic member  293   a  may press the cam member  292  in the first axial direction {circle around ( 1 )}. According to an embodiment, an elastic force may be applied to the cam member  292  in the first axial direction {circle around ( 1 )} by the compressed first elastic member  293   a , and thus a frictional force between the first cam  273  of the first arm  270  and the third cam  2921  of the cam member  292  may be increased. 
     In an embodiment, the second elastic member  293   b  may be disposed between the cam member  292  and the shaft bracket  294 . The second elastic member  293   b  may be coupled to the second arm shaft  266 . For example, the second elastic member  293   b  may include a coil spring that can be axially compressed or uncompressed. The second elastic member  293   b  may be compressed or uncompressed in response to rotation of the second arm  280 . For example, the second elastic member  293   b  may be compressed when the cam member  292  moves in the second axial direction {circle around ( 2 )}, and the compressed second elastic member  293   b  may press the cam member  292  in the first axial direction {circle around ( 1 )}. According to an embodiment, an elastic force may be applied to the cam member  292  in the first axial direction {circle around ( 1 )} by the compressed second elastic member  293   b , and thus a frictional force between the second cam  283  of the second arm  280  and the fourth cam  2922  of the cam member  292  may be increased. 
     In an embodiment, when the electronic device  100  is in a fully folded state, the support structure  203  may support the display  140  such that the display  140  forms a predetermined shape. For example, the support structure  203  may be configured to rotate about an axis of rotation (e.g., axes of rotation R 3  and R 4  of  FIGS. 18A, 18B , and  19 ) by a specified range relative to the rotary members  220  and  230  by the restoring force of the display  140  in a folding motion. In an embodiment, the support structure  203  may include the first guide member  240 , the second guide member  250 , the first rotary plate  261 , and the second rotary plate  262 . 
     In an embodiment, the first guide member  240  may be coupled to the first rotary member  220  so as to be rotatable along a predetermined path. The first guide member  240  may be disposed in the first opening area  223  of the first rotary member  220 . For example, the first guide member  240  may include first guide grooves  241  in which the first guide protrusions  224  of the first rotary member  220  are accommodated. 
     In an embodiment, the second guide member  250  may be coupled to the second rotary member  230  so as to be rotatable along a predetermined path. The second guide member  250  may be disposed in the second opening area  233  of the second rotary member  230 . For example, the second guide member  250  may include second guide grooves  251  in which the second guide protrusions  234  of the second rotary member  230  are accommodated. 
     In an embodiment, the first rotary plate  261  may be coupled to the first guide member  240 . For example, the first rotary plate  261 , together with the first guide member  240 , may rotate along a predetermined path relative to the first rotary member  220 . The first rotary plate  261  may be brought into contact with at least a partial area of the display  140 , and in a folding motion, the restoring force of the display  140  may act on at least part of the first rotary plate  261 . For example, the first rotary plate  261  and the first guide member  240  may be configured to rotate relative to the first rotary member  220  by the restoring force of the display  140  applied to the first rotary plate  261 . 
     In an embodiment, the first rotary plate  261  may include a first support portion  261   a  extending in the axial directions, second support portions  261   b  extending from opposite axial end portions of the first support portion  261   a  in a direction perpendicular to the axial directions, and a third support portion  261   c  extending from the first support portion  261   a  in the direction perpendicular to the axial directions so as to be located between the second support portions  26   1   b.  A first opening (not illustrated) may be formed between the second support portion  26   1   b  and the third support portion  261   c.  Some components of the hinge structure  200  may be exposed through the first opening when the first rotary plate  261  is viewed from above. As the first opening is formed in the first rotary plate  261 , the first rotary plate  261  may not interfere and/or collide with other components of the hinge structure  200  when the first rotary plate  261  rotates. 
     In an embodiment, the second support portion  261   b  may be disposed between the first coupling portion  213  and the second coupling portion  214  of the fixed member  210  (e.g., refer to  FIG. 4 ). For example, when the first rotary plate  261  rotates, the second support portion  26   1   b  may rotate between the first coupling portion  213  and the second coupling portion  214 . For example, the fixed member  210  may include a third coupling portion  215  coupled to the hinge housing  130 , and the first coupling portion  213  and the second coupling portion  214  may protrude from the third coupling portion  215 . Accordingly, a space in which the second support portion  261   b  of the first rotary plate  261  is rotatable may be secured between the first coupling portion  213  and the second coupling portion  214 . For example, when the hinge structure  200  is viewed from above, the second support portion  261   b  may be located between the first coupling portion  213  and the second coupling portion  214  and may overlap the third coupling portion  215 . 
     In an embodiment, the second rotary plate  262  may be coupled to the second guide member  250 . For example, the second rotary plate  262 , together with the second guide member  250 , may rotate along a predetermined path relative to the second rotary member  230 . The second rotary plate  262  may be brought into contact with at least a partial area of the display  140 , and in a folding motion, the restoring force of the display  140  may act on at least part of the second rotary plate  262 . For example, the second rotary plate  262  and the second guide member  250  may be configured to rotate relative to the second rotary member  230  by the restoring force of the display  140  applied to the second rotary plate  262 . 
     In an embodiment, the second rotary plate  262  may include a fourth support portion  262   a  extending in the axial directions, fifth support portions  262   b  extending from opposite axial end portions of the fourth support portion  262   a  in a direction perpendicular to the axial directions, and a sixth support portion  262   c  extending from the fourth support portion  262   a  in the direction perpendicular to the axial directions so as to be located between the fifth support portions  262   b.  A second opening (not illustrated) may be formed between the fifth support portion  262   b  and the sixth support portion  262   c.  Some components of the hinge structure  200  may be exposed through the second opening when the second rotary plate  262  is viewed from above. As the second opening is formed in the second rotary plate  262 , the second rotary plate  262  may not interfere and/or collide with other components of the hinge structure  200  when the second rotary plate  262  rotates. 
     In an embodiment, the fifth support portion  262   b  may be disposed between the first coupling portion  213  and the second coupling portion  214  of the fixed member  210  (e.g., refer to  FIG. 4 ). For example, when the second rotary plate  262  rotates, the fifth support portion  262   b  may rotate between the first coupling portion  213  and the second coupling portion  214 . For example, when the hinge structure  200  is viewed from above, the fifth support portion  262   b  may be located between the first coupling portion  213  and the second coupling portion  214  and may overlap the third coupling portion  215 . 
     Components for forming axes of rotation (or, rotational paths) of the guide members  240  and  250  and the rotary plates  261  and  262  and a rotary motion of the guide members  240  and  250  and the rotary plates  261  and  262  will be described below with reference to  FIGS. 13, 14, 15, 16A, 16B, 17, 18A, 18B, 19, 20, 21A, and 21B . 
     In an embodiment, the first fixed plate  263  may be coupled to the first housing  110  (e.g., the first housing  110  of  FIG. 3 ). The first fixed plate  263  may be spaced apart from the first rotary plate  261  at a specified interval. For example, the first fixed plate  263  may be spaced apart from the first rotary plate  261  by the specified interval in a direction (e.g., the −x-axis direction) perpendicular to the axial directions. The first fixed plate  263  may form substantially the same plane as the first rotary plate  261  and may at least partially overlap other components (e.g., the first rotary member  220 , the first arm  270 , and the first guide member  240 ) of the hinge structure  200 . 
     In an embodiment, the second fixed plate  264  may be coupled to the second housing  120  (e.g., the second housing  120  of  FIG. 3 ). The second fixed plate  264  may be spaced apart from the second rotary plate  262  at a specified interval. For example, the second fixed plate  264  may be spaced apart from the second rotary plate  262  by the specified interval in a direction (e.g., the +x-axis direction) perpendicular to the axial directions. The second fixed plate  264  may form substantially the same plane as the second rotary plate  262  and may at least partially overlap other components (e.g., the second rotary member  230 , the second arm  280 , and the second guide member  250 ) of the hinge structure  200 . 
     In an embodiment, the hinge structure  200  may include center bar  297 . The center bar  297  may extend a predetermined length in the axial directions. The center bar  297  may be disposed between the first arm shaft  265  and the second arm shaft  266 . The center bar  297  may be configured to move in a direction perpendicular to the axial directions depending on rotation of the first arm  270  and the second arm  280 . For example, the center bar  297  may move in the +z-axis direction or the −z-axis direction when the first arm  270  and the second arm  280  rotate. For example, in an unfolded state, the center bar  297  may move in the +z-axis direction to support the display  140 , and in a folding motion, the center bar  297  may move in the −z-axis direction by a predetermined distance to secure a specified separation space between the center bar  297  and the display  140  such that the display  140  is not damaged. 
       FIG. 7  is a view illustrating a coupling structure of the housings, the rotary members, and the fixed member of the electronic device according to an embodiment of the disclosure. 
     Referring to  FIG. 7 , the electronic device  100  according to an embodiment may include the first housing  110 , the second housing  120 , the fixed member  210 , the first rotary member  220 , and the second rotary member  230 . Some of the components of the electronic device  100  illustrated in  FIG. 7  are identical or similar to the components of the electronic device  100  illustrated in  FIGS. 3 to 6 , and therefore repetitive descriptions will hereinafter be omitted. 
     In an embodiment, the first housing  110  may be coupled with the first rotary member  220 . For example, at least part (e.g., a first base portion  222 ) of the first rotary member  220  may be fixed to a partial area of the first plate  111  of the first housing  110  through screw coupling. The second housing  120  may be coupled with the second rotary member  230 . For example, at least part (e.g., a second base portion  232 ) of the second rotary member  230  may be fixed to a partial area of the second plate  121  of the second housing  120  through screw coupling. 
     In an embodiment, the first housing  110  and the second housing  120  may have depressions  114  and  124  (e.g., refer to the depressions  114  and  124  of  FIG. 1 ) in which the hinge housing (e.g., the hinge housing  130  of  FIG. 1 ) is disposed. For example, the first depression area  114  having a specified curvature may be formed on a portion of the first housing  110  that faces the second housing  120 , and the second depression area  124  having a specified curvature may be formed on the second housing  120  to correspond to the first depression area  114  of the first housing  110 . The depressions  114  and  124  may be formed by the depression areas of the first housing  110  and the second housing  120 , respectively. The hinge housing  130  may be disposed in the depressions  114  and  114 , and at least part of the hinge housing  130  may be located between the depressions  114  and  124  and the fixed member  210 .  FIG. 7  may be a view in which the hinge housing  130  is omitted. However, in the case where the hinge housing  130  is disposed, at least part of the hinge housing  130  may overlap the fixed member  210  when the plates  111  and  121  of the housings  110  and  120  are viewed from above. For example, when the electronic device  100  is in an unfolded state (e.g., refer to  FIG. 2A ) as illustrated in  FIG. 7 , the hinge housing  130  may be hidden by the depressions  114  and  124  and may not be exposed on the exterior of the electronic device  100 . 
     In an embodiment, the fixed member  210  may be coupled to the hinge housing  130  disposed in the depressions  114  and  124 . For example, the fixed member  210  may be fixedly coupled to the hinge housing  130  through screw coupling. The fixed member  210  may be coupled with the first rotary member  220  and the second rotary member  230 . For example, the first rotary member  220  and the second rotary member  230  may be coupled to the fixed member  210  so as to be rotatable about the first connecting shaft  211  and the second connecting shaft  212 , respectively. According to an embodiment, when the first housing  110  is folded or unfolded, the first housing  110  and the first rotary member  220  may rotate about the first connecting shaft  211  (or, the first axis of rotation R 1 ) relative to the fixed member  210  fixed to the hinge housing  130 . When the second housing  120  is folded or unfolded, the second housing  120  and the second rotary member  230  may rotate about the second connecting shaft  212  (or, the second axis of rotation R 2 ) relative to the fixed member  210  fixed to the hinge housing  130 . 
     In an embodiment, the fixed member  210  may include the first coupling portion  213  coupled to the rotary member  220  and the second rotary member  230  and the third coupling portion  215  coupled to the hinge housing  130 . For example, the first coupling portion  213  may have through-holes formed therein (e.g., the first through-hole  216  and the second through-hole  217  of  FIG. 6 ) into which the first connecting shaft  211  and the second connecting shaft  212  are inserted. For example, the third coupling portion  215  may have a fastening hole (not illustrated) for screw coupling with the hinge housing  130 . 
     In an embodiment, the first rotary member  220  may include the first base portion  222  coupled to the first housing  110  and the first extension  221  rotatably coupled to the fixed member  210 . The first base portion  222  may be coupled to the first plate  111  of the first housing  110 . The first extension  221  may extend from a portion of the first base portion  222  toward the fixed member  210 . For example, the first extension  221  may extend from the first base portion  222  toward the fixed member  210  in a direction perpendicular to the axial directions by a specified length. 
     In an embodiment, at least part of the first extension  221  may be disposed between the first frame  112  of the first housing  110  and the first coupling portion  213  of the fixed member  210 . The first connecting shaft  211  may pass through at least part of the first coupling portion  213  and at least part of the first extension  221  in the axial directions. For example, the first extension  221  may be coupled to the first coupling portion  213  through the first connecting shaft  211 , and thus the first rotary member  220  may rotate about the first connecting shaft  211  (or, the first axis of rotation R 1 ) relative to the fixed member  210 . Referring to  FIG. 7 , the first extension  221  of the first rotary member  220  may overlap at least part of the first frame  112  when a portion of the first frame  112  of the first housing  110  that faces the axial directions is viewed. 
     In an embodiment, the second rotary member  230  may include the second base portion  232  coupled to the second housing  120  and the second extension  231  rotatably coupled to the fixed member  210 . The second base portion  232  may be coupled to the second plate  121  of the second housing  120 . The second extension  231  may extend from a portion of the second base portion  232  toward the fixed member  210 . For example, the second extension  231  may extend from the second base portion  232  toward the fixed member  210  in a direction perpendicular to the axial directions by a specified length. 
     In an embodiment, at least part of the second extension  231  may be disposed between the second frame  122  of the second housing  120  and the first coupling portion  213  of the fixed member  210 . The second connecting shaft  212  may pass through at least part of the first coupling portion  213  and at least part of the second extension  231  in the axial directions. For example, the second extension  231  may be coupled to the first coupling portion  213  through the second connecting shaft  212 , and thus the second rotary member  230  may rotate about the second connecting shaft  212  (or, the second axis of rotation R 2 ) relative to the fixed member  210 . Referring to  FIG. 7 , the second extension  231  of the second rotary member  230  may overlap at least part of the second frame  122  when a portion of the second frame  122  of the second housing  120  that faces the axial directions is viewed. 
       FIG. 8  is a view illustrating a coupling structure of rotary members, arm shafts, and arms of a hinge structure according to an embodiment of the disclosure. 
       FIGS. 9A and 9B  are a view illustrating a coupling structure of rotary members, arm shafts, and arms of a hinge structure according to various embodiments of the disclosure. 
       FIGS. 9A and 9B  are a view of the hinge structure of  FIG. 8  as viewed in a first rotational axis direction. For example,  FIG. 9A  may be a view in which the rotary members of  FIG. 8  are omitted.  FIG. 9B  may be a view in which the arm shafts and the arms of  FIG. 8  are omitted. 
     Referring to  FIGS. 8, 9A, and 9B , the hinge structure  200  according to an embodiment may include the first rotary member  220 , the second rotary member  230 , the first arm shaft  265 , the second arm shaft  266 , the first arm  270 , and the second arm  280 . 
     In an embodiment, the hinge structure  200  may be configured such that the arms  270  and  280  are coupled to the arm shafts  265  and  266  to rotate together with the arm shafts  265  and  266  and the rotary members  220  and  230  are coupled to the arms  270  and  280  to rotate together with the arms  270  and  280  and slide relative to the arms  270  and  280 . In various embodiments, as the arms  270  and  280  and the rotary members  220  and  230  of the hinge structure  200  are coupled to slide relative to each other, the arm shafts  265  and  266 , which are the centers of rotation of the arms  270  and  280 , and the axes of rotation (e.g., the connecting shafts  211  and  212  of  FIGS. 4 to 6 ) of the rotary members  220  and  230  may be implemented to be different from each other. For example, the arm shafts  265  and  266  may be located under the display (e.g., the display  140  of  FIG. 1 ) to maximize torque, and the rotary shafts  211  and  212  of the rotary members  220  and  230  may be located over the display  140  when the display  140  is viewed in the cross-section (e.g., refer to  FIG. 12 ). For example, the arms  270  and  280  and the rotary members  220  and  230  may be connected (or, interlocked) to rotate together, but may rotate about different axes of rotation while sliding relative to each other. 
     In an embodiment, the first arm shaft  265 , when viewed in the axial directions, may include a first end portion  265   a  that faces the first axial direction {circle around ( 1 )} and a second end portion  265   b  that faces the second axial direction {circle around ( 2 )}. The first end portion  265   a  may be rotatably inserted into an opening (e.g., the first opening  218  of  FIG. 6 ) of the fixed member (e.g., the fixed member  210  of  FIG. 6 ). The first gear  267   a  may be disposed on an outer circumferential surface of the first arm shaft  265  that is adjacent to the first end portion  265   a  and may rotate together with the first arm shaft  265 . For example, the first gear  267   a  may be coupled to the first arm shaft  265 , or may be integrally formed with the first arm shaft  265 . A fixing groove (not illustrated) into which the first fixing ring  296   a  is inserted may be formed on the second end portion  265   b.    
     In an embodiment, the first arm shaft  265  may include a first shaft portion S 1  that is located between the first end portion  265   a  and the second end portion  265   b  and that has a non-circular (or, polygonal) cross-section and a second shaft portion S 2  that is located between the first shaft portion S 1  and the first end portion  265   a  and that has a circular cross-section. For example, when the first arm shaft  265  is viewed in cross-sections perpendicular to the axial directions, the first shaft portion S 1  and the second shaft portion S 2  may be formed in different shapes. For example, referring to the drawings, the first shaft portion S 1  may have a larger cross-section than the second shaft portion S 2 . In another example, the first shaft portion S 1  may have a smaller cross-section than the second shaft portion S 2 , or may have substantially the same cross-section as the second shaft portion S 2 . The first arm  270  and the cam member (e.g., the first portion  292   a  of the cam member  292  of  FIGS. 10A, 10B, and 10C ) may be coupled to the first shaft portion S 1  of the first arm shaft  265 . In various embodiments, the first shaft portion S 1  may include flat areas S 12  that are substantially flat and round areas S 11  that are substantially curved. 
     In an embodiment, the first arm  270  may include a first portion  272  coupled to the first arm shaft  265  and a second portion  271  that extends from the first portion  272  and that is slidably coupled to the first rotary member  220 . For example, the second portion  271  may extend from the first portion  272  in a direction substantially perpendicular to the axial directions. The first sliding pin  274  may be disposed in the second portion  271 , and the second portion  271  may be slidably coupled to the first rotary member  220  through the first sliding pin  274 . 
     In an embodiment, the first portion  272  of the first arm  270  may have a through-hole  276  formed therein into which the first arm shaft  265  is inserted. The through-hole  276  may be formed in a shape substantially corresponding to the first shaft portion S 1  of the first arm shaft  265  such that the first arm  270  rotates together with the first arm shaft  265 . Referring to  FIG. 9A , the first shaft portion S 1  of the first arm shaft  265  may be press-fit into the through-hole  276  of the first arm  270 . For example, the first shaft portion S 1  of the first arm shaft  265  may be formed to be larger than the through-hole  276  so as to be press-fit into the through-hole  276 . For example, the first shaft portion S 1  may be press-fit into the through-hole  276  such that the flat areas S 12  and the round areas S 11  are brought into close contact with the inner surfaces of the through-hole  276 . Accordingly, the first arm  270  may rotate together with the first arm shaft  265  and may not move in the axial directions. For example, the first arm  270  may be axially fixed in a specified position on the first shaft portion S 1  of the first arm shaft  265 . 
     In an embodiment, the first cam  273  may be formed on the first portion  272  of the first arm  270 . The first cam  273  may be formed around the through-hole  276  to surround the first arm shaft  265 . The first cam  273  may be formed on a surface of the first portion  272  of the first arm  270  that faces the second axial direction {circle around ( 2 )}, or may be formed on a surface of the first portion  272  that faces toward the second end portion  265   b  of the first arm shaft  265 . The first cam  273  may be engaged with the third cam (e.g., the third cam  2921  of the cam member  292  of  FIGS. 4 to 6 ) of the cam member. 
     In an embodiment, the second portion  271  of the first arm  270  may have the first pin hole  275  formed therein into which the first sliding pin  274  is inserted. The first sliding pin  274  may be coupled to the first arm  270  so as to move together with the first arm  270 . For example, the first sliding pin  274  may be press-fit into the first pin hole  275  of the first arm  270 . At least part of the first sliding pin  274  may be accommodated in the first sliding groove  227  of the first rotary member  220 . For example, the first sliding pin  274  may be accommodated in the first sliding groove  227  so as to slide along the first sliding groove  227  when the first arm  270  rotates. The first sliding pin  274  may move along the first sliding groove  227  in the state of being press-fit into the first pin hole  275  of the first arm  270 . Accordingly, the first arm  270  may be slidably coupled to the first rotary member  220 . For example, when the first rotary member  220  rotates, the first arm  270  may slide relative to the first rotary member  220  while rotating about the first arm shaft  265 . 
     Referring to  FIG. 9B , when the electronic device  100  is in an unfolded state, the first sliding pin  274  may be located in a first position L 1  in the first sliding groove  227 , and when the electronic device  100  is in a fully folded state, the first sliding pin  274  may move along the first sliding groove  227  so as to be located in a second position L 2 . For example, the first position L 1  may correspond to one end portion of the first sliding groove  227 , and the second position L 2  may correspond to an opposite end portion of the first sliding groove  227 . The first arm  270  may slide relative to the first rotary member  220  as the first sliding pin  274  moves along the first sliding groove  227 . The sliding motion of the first arm  270  and the first sliding pin  274  will be described below with reference to  FIG. 12 . 
     In an embodiment, the second aim shaft  266 , when viewed in the axial directions, may include a first end portion  266   a  that faces the first axial direction {circle around ( 1 )} and a second end portion  266   b  that faces the second axial direction {circle around ( 2 )}. The first end portion  266   a  may be rotatably inserted into an opening (e.g., the second opening  219  of  FIG. 6 ) of the fixed member (e.g., the fixed member  210  of  FIG. 6 ). The second gear  267   b  may be disposed on an outer circumferential surface of the second arm shaft  266  that is adjacent to the first end portion  266   a  and may rotate together with the second arm shaft  266 . For example, the second gear  267   b  may be coupled to the second arm shaft  266 , or may be integrally formed with the second arm shaft  266 . A fixing groove (not illustrated) into which the second fixing ring  296   b  is inserted may be formed on the second end portion  266   b.    
     In an embodiment, the second arm shaft  266  may include a first shaft portion S 1  that is located between the first end portion  266   a  and the second end portion  266   b  and that has a non-circular (or, polygonal) cross-section and a second shaft portion S 2  that is located between the first shaft portion S 1  and the first end portion  266   a  and that has a circular cross-section. For example, when the second arm shaft  266  is viewed in cross-sections perpendicular to the axial directions, the first shaft portion S 1  and the second shaft portion S 2  may be formed in different shapes. For example, referring to the drawings, the first shaft portion S 1  may have a larger cross-section than the second shaft portion S 2 . In another example, the first shaft portion S 1  may have a smaller cross-section than the second shaft portion S 2 . The second arm  280  and the cam member (e.g., the second portion  292   b  of the cam member  292  of  FIGS. 10A, 10B, and 10C ) may be coupled to the first shaft portion S 1  of the second arm shaft  266 . In various embodiments, the first shaft portion S 1  may include flat areas S 12  that are substantially flat and round areas S 11  that are substantially curved. 
     In an embodiment, the second aim  280  may include a first portion  282  coupled to the second arm shaft  266  and a second portion  281  that extends from the first portion  282  and that is slidably coupled to the second rotary member  230 . For example, the second portion  281  may extend from the first portion  282  in a direction substantially perpendicular to the axial directions. The second sliding pin  284  may be disposed in the second portion  281 , and the second portion  281  may be slidably coupled to the second rotary member  230  through the second sliding pin  284 . 
     In an embodiment, the first portion  282  of the second arm  280  may have a through-hole  286  formed therein into which the second arm shaft  266  is inserted. The through-hole  286  may be formed in a shape substantially corresponding to the first shaft portion S 1  of the second arm shaft  266  such that the second arm  280  rotates together with the second arm shaft  266 . Referring to  FIG. 9A , the first shaft portion S 1  of the second arm shaft  266  may be press-fit into the through-hole  286  of the second arm  280 . For example, the first shaft portion S 1  of the second arm shaft  266  may be formed to be larger than the through-hole  286  so as to be press-fit into the through-hole  286 . For example, the first shaft portion S 1  may be press-fit into the through-hole  286  such that the flat areas S 12  and the round areas S 11  are brought into close contact with the inner surfaces of the through-hole  286 . Accordingly, the second arm  280  may rotate together with the second arm shaft  266  and may not move in the axial directions. For example, the second arm  280  may be axially fixed in a specified position on the first shaft portion Si of the second arm shaft  266 . 
     In an embodiment, the second cam  283  may be formed on the first portion  282  of the second arm  280 . The second cam  283  may be formed around the through-hole  286  to surround the second arm shaft  266 . The second cam  283  may be formed on a surface of the first portion  282  of the second arm  280  that faces the second axial direction {circle around ( 2 )}, or may be formed on a surface of the first portion  282  that faces toward the second end portion  266   b  of the second arm shaft  266 . The second cam  283  may be engaged with the fourth cam (e.g., the fourth cam  2922  of the cam member  292  of  FIGS. 4 to 6 ) of the cam member. 
     In an embodiment, the second portion  281  of the second arm  280  may have the second pin hole  285  formed therein into which the second sliding pin  284  is inserted. The second sliding pin  284  may be coupled to the second arm  280  so as to move together with the second arm  280 . For example, the second sliding pin  284  may be press-fit into the second pin hole  285  of the second arm  280 . At least part of the second sliding pin  284  may be accommodated in the second sliding groove  237  of the second rotary member  230 . For example, the second sliding pin  284  may be accommodated in the second sliding groove  237  so as to slide along the second sliding groove  237  when the second arm  280  rotates. The second sliding pin  284  may move along the second sliding groove  237  in the state of being press-fit into the second pin hole  285  of the second arm  280 . Accordingly, the second arm  280  may be slidably coupled to the second rotary member  230 . For example, when the second rotary member  230  rotates, the second arm  280  may slide relative to the second rotary member  230  while rotating about the second aim shaft  266 . 
     Referring to  FIG. 9B , when the electronic device  100  is in an unfolded state, the second sliding pin  284  may be located in a first position L 1  in the second sliding groove  237 , and when the electronic device  100  is in a fully folded state, the second sliding pin  284  may move along the second sliding groove  237  so as to be located in a second position L 2 . For example, the first position L 1  may correspond to one end portion of the second sliding groove  237 , and the second position L 2  may correspond to an opposite end portion of the second sliding groove  237 . The second arm  280  may slide relative to the second rotary member  230  as the second sliding pin  284  moves along the second sliding groove  237 . The sliding motion of the second arm  280  and the second sliding pin  284  will be described below with reference to  FIG. 12 . 
       FIG. 10A  is a view illustrating a cam member of the hinge structure according to an embodiment of the disclosure. 
       FIG. 10B  is a view illustrating a coupling structure of arm shafts and a cam member of a hinge structure according to an embodiment of the disclosure. 
       FIG. 10C  is a view illustrating a coupling structure of arm shafts and a cam member of a hinge structure according to an embodiment of the disclosure. 
       FIG. 10A  illustrates a perspective view of the cam member.  FIG. 10B  illustrates a coupling of the arm shafts and the cam member.  FIG. 10C  illustrates a sectional view taken along line A-A′ illustrated in  FIG. 10B . 
     Referring to  FIGS. 10A, 10B, and 10C  the hinge structure  200  according to an embodiment may include the cam member  292 , the first arm shaft  265 , and the second arm shaft  266 . The first arm shaft  265  and the second arm shaft  266  may pass through at least parts of the cam member  292 . 
     In an embodiment, the cam member  292  may include the first portion  292   a  through which the first arm shaft  265  passes, the second portion  292   b  through which the second arm shaft  266  passes, and a third portion  292   c  connecting the first portion  292   a  and the second portion  292   b.  The third cam  2921  and the fourth cam  2922  engaged with the cams (e.g., the first cam  273  and the second cam  283  of  FIGS. 8, 9A , and  9 B) formed on the arms  270  and  280  may be formed on at least parts (e.g., the first portion  292   a  and the second portion  292   b ) of the cam member  292 . 
     In an embodiment, the first portion  292   a  may include the third cam  2921  formed to surround the first arm shaft  265 . For example, the third cam  2921  may be formed on a surface of the first portion  292   a  that faces the first axial direction {circle around ( 1 )}. The third cam  2921  may be engaged with the first cam (e.g., the first cam  273  of  FIGS. 8, 9A, and 9B ) of the first arm (e.g., the first arm  270  of  FIGS. 8, 9A, and 9B ). Although the first arm  270  is not illustrated in  FIGS. 10A, 10B, and 10C , the first arm  270  may be coupled to the first arm shaft  265  such that the first cam  273  is located between the first gear  267   a  and the first portion  292   a.    
     In an embodiment, the second portion  292   b  may include the fourth cam  2922  formed to surround the second arm shaft  266 . For example, the fourth cam  2922  may be formed on a surface of the second portion  292   b  that faces the first axial direction {circle around ( 1 )}. The fourth cam  2922  may be engaged with the second cam (e.g., the second cam  283  of  FIGS. 8, 9A, and 9B ) of the second arm (e.g., the second arm  280  of  FIGS. 8, 9A, and 9B ). Although the second arm  280  is not illustrated in  FIGS. 10A, 10B, and 10C , the second arm  280  may be coupled to the second arm shaft  266  such that the second cam  283  is located between the second gear  267   b  and the second portion  292   b.    
     In an embodiment, the third portion  292   c  may connect the first portion  292   a  and the second portion  292   b  such that the cam member  292  moves along the first arm shaft  265  and the second arm shaft  266  in the axial directions. For example, the third portion  292   c  may extend from part of the first portion  292   a  to the second portion  292   b  in a direction perpendicular to the axial directions. For example, when the arms  270  and  280  coupled to the arm shafts  265  and  266  rotate, the cams (e.g., the first cam  273  and the second cam  283 ) of the arms  270  and  280  and the cams (e.g., the third cam  2921  and the fourth cam  2922 ) of the cam member  292  may move toward, or away from, each other in the axial directions. The third portion  292   c  may connect the first portion  292   a  and the second portion  292   b  such that the first portion  292   a  and the second portion  292   b  of the cam member  292  linearly move in the axial directions without rotating about the first arm shaft  265  and the second arm shaft  266 . 
     In an embodiment, the cam member  292  may be coupled to the arm shafts  265  and  266  to linearly move in the axial directions without rotating together with the arm shafts  265  and  266  when the arm shafts  265  and  266  rotate. For example, the first portion  292   a  of the cam member  292  may have a first hole  2923  formed therein into which the first arm shaft  265  is inserted. The second portion  292   b  of the cam member  292  may have a second hole  2924  formed therein into which the second arm shaft  266  is inserted. The cam member  292  may be configured such that the arm shafts  265  and  266  rotate in the first hole  2923  and the second hole  2924  independently of the cam member  292 . 
     In an embodiment, the first shaft portion S 1  of the first arm shaft  265  may be inserted into the first hole  2923 . The first hole  2923  may be formed to be larger than the first shaft portion S 1 . For example, the first shaft portion S 1  may be formed to have a non-circular cross-section, and the first hole  2923  may be formed in a circular shape so as to be separated from rotation of the first shaft portion S 1 . The first hole  2923  may be formed to be larger than the non-circular cross-section of the first shaft portion S 1  such that the first shaft portion S 1  rotates in the first hole  2923  independently of the first portion  292   a.  For example, the inner surface of the first hole  2923  may make contact with the round areas S 11  of the first shaft portion S 1 , but may not make contact with the flat areas S 12  of the first shaft portion S 1 . 
     In an embodiment, the first shaft portion S 1  of the second arm shaft  266  may be inserted into the second hole  2924 . The second hole  2924  may be formed to be larger than the first shaft portion S 1 . For example, the first shaft portion S 1  may be formed to have a non-circular cross-section, and the second hole  2924  may be formed in a circular shape so as to be separated from rotation of the first shaft portion S 1 . The second hole  2924  may be formed to be larger than the non-circular cross-section of the first shaft portion S 1  such that the first shaft portion S 1  rotates in the second hole  2924  independently of the second portion  292   b.  For example, the inner surface of the second hole  2924  may make contact with the round areas S 11  of the first shaft portion S 1 , but may not make contact with the flat areas S 12  of the first shaft portion S 1 . 
     In an embodiment, as the first arm shaft  265  is inserted into the first hole  2923  and the second arm shaft  266  is inserted into the second hole  2924 , the cam member  292  may be guided to move along the arm shafts  265  and  266  in the axial directions. For example, the third cam  2921  of the cam member  292  may be engaged with the first cam of the first arm (e.g., the first cam  273  of the first arm  270  of  FIG. 8 ), and the fourth cam  2922  of the cam member  292  may be engaged with the second cam of the second arm (e.g., the second cam  283  of the second arm  280  of  FIG. 8 ). When the arms  270  and  280  rotate together with the arm shafts  265  and  266 , the cams  273  and  283  of the arms  270  and  280  may rotate relative to the cams  2921  and  2922  of the cam member  292 , and therefore the positions of the cams  2921  and  2922  of the cam member  292  relative to the cams  273  and  283  of the arms  270  and  280  may be changed. The cam member  292  may move along the arm shafts  265  and  266  in the axial directions depending on the change in the positions of the cams  2921  and  2922  of the cam member  292  relative to the cams  273  and  283  of the arms  270  and  280 . 
       FIG. 11A  is a view illustrating a hinge structure and a display in an unfolded state of an electronic device according to an embodiment of the disclosure. 
       FIG. 11B  is a view illustrating a hinge structure and a display in a fully folded state of an electronic device according to an embodiment of the disclosure. 
       FIG. 12  is a view illustrating a folding motion of a hinge structure and a display according to an embodiment of the disclosure. 
       FIG. 11A  and part  1201  of  FIG. 12  are views illustrating the display and the hinge structure when the electronic device is in the unfolded state.  FIG. 11B  and part  1202  of  FIG. 12  are views illustrating the display and the hinge structure when the electronic device is in the fully unfolded state. Part  1201  of  FIG. 12  is a sectional view taken along line B-B′ illustrated in  FIG. 11A , and part  1201  of  FIG. 12  is a sectional view taken along line C-C′ illustrated in  FIG. 11B . 
     Referring to  FIGS. 11A, 11B, and 12 , the electronic device  100  according to an embodiment may include the display  140  and the hinge structure  200 . For example, the electronic device  100  may be configured such that at least part of the display  140  is folded or unfolded together with the housings  110  and  120  as the housings (e.g., the housings  110  and  120  of  FIGS. 1 to 3 ) are folded or unfolded by the hinge structure  200 .  FIGS. 11A, 11B, and 12  may be views in which the housings  110  and  120  of the electronic device  100  are omitted. In an embodiment, the hinge structure  200  may include the fixed member  210 , the rotary members  220  and  230 , the arms  270  and  280 , the arm shafts  265  and  266 , the rotary plates  261  and  262 , and the fixed plates  263  and  264 . 
     In an embodiment, at least part of the display  140  may be supported by some components of the hinge structure  200 . For example, some components of the hinge structure  200  may be configured to support the display  140  together with the plates (e.g., the first plate  111  and the second plate  121  of  FIG. 3 ) of the housings  110  and  120 . For example, the first rotary plate  261 , the second rotary plate  262 , the first fixed plate  263 , and the second fixed plate  264  of the hinge structure  200  may each support a partial area of the rear surface (e.g., a surface facing the −z-axis direction) of the display  140 . 
     In an embodiment, the display  140  may include the first area  141 , the second area  142 , and the folding area  143  defined as an area between the first area  141  and the second area  142 . The first area  141  and the second area  142  may remain substantially flat in a folding motion and an unfolding motion. The folding area  143  may be partially folded or unfolded in the folding motion and the unfolding motion. According to an embodiment, in the fully folded state (part  1202  of  FIG. 12 ), the display  140  may be supported by the support structure (e.g., the support structure  203  of  FIGS. 4 to 6 ) such that the folding area  143  forms a specified shape. For example, referring to part  1202  of  FIG. 12 , the display  140  may be configured such that in the fully folded state, the folding area  143  forms an in-folding area (not illustrated) (e.g., an in-folding area  144  of  FIG. 17 ) and out-folding areas (not illustrated) (e.g., out-folding areas  145  and  146  of  FIG. 17 ) that extend from the in-folding area. For example, in the fully folded state, the folding area  143  may form a water-drop shape or a jar shape. 
     In an embodiment, in the unfolded state (e.g., part  1201  of  FIG. 12 ), the first rotary plate  261  and the second rotary plate  262  may be disposed substantially parallel to the display  140 . In the fully folded state (e.g., part  1202  of  FIG. 12 ), the first rotary plate  261  and the second rotary plate  262  may form a specified angle with at least partial areas of the display  140 . For example, the first rotary plate  261  and the second rotary plate  262  may form a specified angle with the first area  141  and the second area  142  by rotating about virtual axes of rotation (e.g., the axes of rotation R 3  and R 4  of  FIGS. 18A, 18B, and 19 ) in a predetermined range by a repulsive force of the display  140  generated in a folding motion. According to an embodiment, the display  140  may be configured such that the folding area  143  forms a specified shape as the rotary plates  261  and  262  rotate together with the guide members  240  and  250  relative to the rotary members  220  and  230 . An interlocking structure of the display  140  and the support structure  203  will be described below with reference to  FIGS. 18A, 18B, 19, and 20 . 
     In an embodiment, the first fixed plate  263  and the second fixed plate  264  may support partial areas of the display  140  and may move together with the display  140  in folding and unfolding motions. For example, the first fixed plate  263  and the second fixed plate  264  may be attached to the partial areas of the display  140  (e.g., refer to  FIGS. 21A and 21B ). For example, the first fixed plate  263  may be attached to part of the first area  141 , and the second fixed plate  264  may be attached to part of the second area  142 . 
     Hereinafter, a rotary motion of the rotary members  220  and  230  of the hinge structure  200  according to an embodiment will be described with reference to  FIGS. 11A, 11B, and 12 . 
     In an embodiment, the rotary members  220  and  230  may be coupled to the fixed member  210  so as to be rotatable about the axes of rotation R 1  and R 2 . For example, the first rotary member  220  and the second rotary member  230  may be coupled to the fixed member  210  so as to be rotatable about the first connecting shaft  211  and the second connecting shaft  212 , respectively. For example, the first rotary member  220  may be connected to part of the fixed member  210  through the first connecting shaft  211  (e.g., refer to  FIG. 7 ). The first connecting shaft  211  may pass through the first extension  221  of the first rotary member  220  and the fixed member  210 . For example, the second rotary member  230  may be connected to another part of the fixed member  210  through the second connecting shaft  212  (e.g., refer to  FIG. 7 ). The second connecting shaft  212  may pass through the second extension  231  of the second rotary member  230  and the fixed member  210 . 
     For example, the first connecting shaft  211  may form the first axis of rotation R 1 . The first axis of rotation R 1  may be defined as a virtual line passing through the center of the first connecting shaft  211  and extending parallel to the axial directions. The second connecting shaft  212  may form the second axis of rotation R 2 . The second axis of rotation R 2  may be defined as a virtual line passing through the center of the second connecting shaft  212  and extending parallel to the axial directions. 
     In an embodiment, the first rotary member  220  may include the first extension  221  coupled to the fixed member  210  and the first base portion  222  coupled to the first housing (e.g., the first housing  110  of  FIG. 7 ). In an embodiment, the first extension  221  may be coupled to the fixed member  210  through the first connecting shaft  211 , and thus the first rotary member  220  may rotate about the first connecting shaft  211  (e.g., the first axis of rotation R 1 ) relative to the fixed member  210 . For example, the first base portion  222  may be coupled to the first housing  110 , and the first rotary member  220  may rotate about the first connecting shaft  211  together with the first housing  110  when the first housing  110  is folded or unfolded. 
     In an embodiment, the second rotary member  230  may include the second extension  231  coupled to the fixed member  210  and the second base portion  232  coupled to the second housing (e.g., the second housing  120  of  FIG. 7 ). In an embodiment, the second extension  231  may be coupled to the fixed member  210  through the second connecting shaft  212 , and thus the second rotary member  230  may rotate about the second connecting shaft  212  (e.g., the second axis of rotation R 2 ) relative to the fixed member  210 . For example, the second base portion  232  may be coupled to the second housing  120 , and thus the second rotary member  230  may rotate about the second connecting shaft  212  together with the second housing  120  when the second housing  120  is folded or unfolded. 
     In an embodiment, the first axis of rotation R 1  and the second axis of rotation R 2  may be parallel to the axial directions of the hinge structure  200 . The first axis of rotation R 1  and the second axis of rotation R 2  may be formed in positions spaced apart from the display  140  in the −z-axis direction. For example, the first connecting shaft  211  and the second connecting shaft  212  may be coupled to the fixed member  210  such that the centers thereof are located in lower positions in the z-axis direction than the display  140 . In an embodiment, the first connecting shaft  211  may be parallel to the first arm shaft  265 , but may be spaced apart from the first arm shaft  265  so as not to form the same axis as the first arm shaft  265 . The second connecting shaft  212  may be parallel to the second arm shaft  266 , but may be spaced apart from the second arm shaft  266  so as not to form the same axis as the second arm shaft  266 . 
     In an embodiment, in a folding motion of the electronic device  100 , the first rotary member  220  may rotate about the first connecting shaft  211  in a first rotational direction (e.g., the clockwise direction, based on  FIGS. 11A, 11B, and 12 ), and the second rotary member  230  may rotate about the second connecting shaft  212  in the direction opposite to the first rotational direction (e.g., the counterclockwise direction, based on  FIGS. 11A, 11B, and 12 ). 
     In an embodiment, in the unfolded state, the first extension  221  of the first rotary member  220  and the second extension  231  of the second rotary member  230  may be located on substantially the same straight line. For example, the first extension  221  and the second extension  231  may form an angle of 180 degrees. In the fully unfolded state, the first extension  221  of the first rotary member  220  and the second extension  231  of the second rotary member  230  may be located to face each other in parallel. For example, the first extension  221  and the second extension  231  may form substantially 0 degrees. 
     Hereinafter, a rotary motion and a sliding motion of the arms  270  and  280  and the rotary members  220  and  230  of the hinge structure  200  according to an embodiment will be described with reference to  FIG. 12 . 
     In an embodiment, when the hinge structure  200  is folded or unfolded, the rotary members  220  and  230  and the arms  270  and  280  may rotate about different axes. For example, the rotary members  220  and  230  and the arms  270  and  280  may rotate along different rotational paths. As the rotational paths of the rotary members  220  and  230  and the rotational paths of the arms  270  and  270  are formed to be different from each other, the arms  270  and  280  may slide relative to the rotary members  220  and  230  when the hinge structure  200  is folded or unfolded. 
     In an embodiment, the first rotary member  220  may rotate about the first connecting shaft  211  (e.g., the first axis of rotation R 1 ) in the first rotational direction. For example, in a folding motion, the first rotary member  220  may rotate in the first rotational direction (e.g., the clockwise direction). For example, based on the unfolded state, the point where the first sliding pin  274  is located in the first rotary member  220  may be defined as a first point A 1 . The first point A 1  of the first rotary member  220  may move along a first rotational path RP 1  in response to a folding motion and an unfolding motion of the electronic device  100 . 
     In an embodiment, the first arm  270  and the first sliding pin  274  may rotate about the first arm shaft  265 . For example, in a folding motion, the first arm  270  and the first sliding pin  274  may rotate together with the first rotary member  220  in the first rotational direction (e.g., the clockwise direction). For example, in the unfolded state, the first sliding pin  274  may be located at the first point A 1  of the first rotary member  220  (e.g., the first position L 1  of  FIGS. 9A and 9B ), and in the fully folded state, the first sliding pin  274  may move along the first sliding groove  227  and may be located in a position (e.g., the second position L 2  of  FIGS. 9A and 9B ) spaced apart from the first point A 1  in the direction perpendicular to the axial directions. The first sliding pin  274  may move along a second rotational path RP 2  in response to a folding motion and an unfolding motion of the electronic device  100 . 
     According to an embodiment, in a folding motion and an unfolding motion of the electronic device  100 , the first arm  270  and the first sliding pin  274  may slide relative to the first rotary member  220 . The first sliding pin  274  may be slidably accommodated in the first sliding groove  227  of the first rotary member  220  in the state of passing through part of the first arm  270 , and thus the sliding motion of the first arm  270  and the first sliding pin  274  may be guided (e.g., refer to  FIG. 9B ). For example, the first sliding groove  227  may be formed in an arc shape having a predetermined curvature. Accordingly, the sliding motion between the first arm  270  and the first rotary member  220  may be smoothly performed. In an embodiment, when a folding motion is performed in the unfolded state, the distance between the first sliding pin  274  and the first point A 1  may increase. When an unfolding motion is performed in the fully folded state, the distance between the first sliding pin  274  and the first point A 1  may decrease. 
     In an embodiment, the first rotational path RP 1  and the second rotational path RP 2  may differ from each other. For example, the first connecting shaft  211  (e.g., the first axis of rotation R 1 ) and the first arm shaft  265  may be parallel to each other, but may not be located on the same line. For example, when the hinge structure  200  is viewed in the cross-section, the first arm shaft  265  may be disposed so as not to overlap the first connecting shaft  211 . 
     In an embodiment, the second rotary member  230  may rotate about the second connecting shaft  212  (e.g., the second axis of rotation R 2 ) in a second rotational direction. For example, in a folding motion, the second rotary member  230  may rotate in the second rotational direction (e.g., the counterclockwise direction, based on  FIG. 12 ) that is opposite to the rotational direction of the first rotary member  220  (e.g., the clockwise direction, based on  FIG. 12 ). For example, based on the unfolded state, the point where the second sliding pin  284  is located in the second rotary member  230  may be defined as a second point A 2 . The second point A 2  of the second rotary member  230  may move along a third rotational path RP 3  in response to a folding motion and an unfolding motion of the electronic device  100 . 
     In an embodiment, the second arm  280  and the second sliding pin  284  may rotate about the second arm shaft  266 . For example, in a folding motion, the second arm  280  and the second sliding pin  284  may rotate together with the second rotary member  230  in the second rotational direction (e.g., the counterclockwise direction, based on  FIG. 12 ). For example, in the unfolded state, the second sliding pin  284  may be located at the second point A 2  of the second rotary member  230  (e.g., the first position L 1  of  FIGS. 9A and 9B ), and in the fully folded state, the second sliding pin  284  may move along the second sliding groove  237  and may be located in a position (e.g., the second position L 2  of  FIGS. 9A and 9B ) spaced apart from the second point A 2  in the direction perpendicular to the axial directions. The second sliding pin  284  may move along a fourth rotational path RP 4  in response to a folding motion and an unfolding motion of the electronic device  100 . 
     According to an embodiment, in a folding motion and an unfolding motion of the electronic device  100 , the second arm  280  and the second sliding pin  284  may slide relative to the second rotary member  230 . The second sliding pin  284  may be slidably accommodated in the second sliding groove  237  of the second rotary member  230  in the state of passing through part of the second arm  280 , and thus the sliding motion of the second arm  280  and the second sliding pin  284  may be guided (e.g., refer to  FIG. 9B ). For example, the second sliding groove  237  may be formed in an arc shape having a predetermined curvature. Accordingly, the sliding motion between the second arm  280  and the second rotary member  230  may be smoothly performed. In an embodiment, when a folding motion is performed in the unfolded state, the distance between the second sliding pin  284  and the second point A 2  may increase. When an unfolding motion is performed in the fully folded state, the distance between the second sliding pin  284  and the second point A 2  may decrease. 
     In various embodiments, the third rotational path RP 3  and the fourth rotational path RP 4  may differ from each other. For example, the second connecting shaft  212  (e.g., the second axis of rotation R 2 ) and the second arm shaft  266  may be parallel to each other, but may not be located on the same line. For example, when the hinge structure  200  is viewed in the cross-section, the second arm shaft  266  may be disposed so as not to overlap the second connecting shaft  212 . 
     Hereinafter, components of the support structure  203  of the hinge structure  200  and a coupling relationship therebetween according to an embodiment will be described with reference to  FIGS. 13, 14, 15, 16A, and 16B . The support structure  203  may include the guide members  240  and  250  and the rotary plates  261  and  262 . 
       FIG. 13  is a view illustrating a rotary member of a hinge structure according to an embodiment of the disclosure. 
       FIG. 14  is a view illustrating a guide member of a hinge structure according to an embodiment of the disclosure. 
       FIG. 15  is a view illustrating a coupling structure of a rotary member and a guide member of a hinge structure according to an embodiment of the disclosure. 
     Referring to  FIGS. 13 to 15 , the hinge structure  200  according to an embodiment may include the rotary member  230  and the guide member  250 , and the guide member  250  may be rotatably coupled to the rotary member  230 . 
     The rotary member  230  and the guide member  250  illustrated in  FIGS. 13 to 15  may be referred to as the second rotary member  230  and the second guide member  250  of  FIGS. 3, 4, 5, 6, 7, 8, 9A, and 9B . However, contents to be described below with reference to  FIGS. 13 to 15  may be identically applied to the first rotary member  220  and the first guide member  240 . 
     Referring to  FIG. 13 , the rotary member  230  according to an embodiment may include a base portion  232  coupled to a housing (e.g., the housing  110  or  120  of  FIG. 7 ) and an extension  231  that extends from the base portion  232  and that is rotatably coupled to a fixed member (e.g., the fixed member  210  of  FIG. 7 ). For example, the base portion  232  may have, on a first surface  2321  thereof, a sliding groove  237  in which a sliding pin (e.g., the sliding pin  274  or  284  of  FIGS. 8, 9A, and 9B ) is accommodated. For example, the extension  231  may have a through-hole  236  formed therein in which a connecting shaft (e.g., the connecting shaft  211  or  212  of  FIG. 7 ) is accommodated. 
     In an embodiment, the rotary member  230  may include an opening area  233  in which the guide member  250  is disposed. For example, the opening area  233  may be formed in at least part of the base portion  232 . The guide member  250  may be rotatably coupled to the inside of the opening area  233 . The guide member  250  may be configured to rotate about a virtual axis of rotation (e.g., the axis of rotation R 3  or R 4  of  FIGS. 18A, 18B, and 19 ) relative to the rotary member  230  along a predetermined path in the opening area  233 . For example, the opening area  233  may be formed between the first surface  2321  of the base portion  232  and the extension  231 . Accordingly, the guide member  250  may be disposed between the extension  231  of the rotary member  230  and the arm  270  or  280  (e.g., refer to  FIGS. 4 and 5 ). 
     In an embodiment, the rotary member  230  may include guide protrusions  234  for guiding rotation of the guide member  250 . For example, the guide protrusions  234  may be accommodated in guide grooves  251  of the guide member  250  and may move along the guide grooves  251  to guide a rotational path of the guide member  250 . According to the illustrated embodiment, the guide protrusions  234  may be formed in an arc shape to correspond to the guide grooves  251  formed in an arc shape. For example, the guide protrusions  234  may be formed in the shape of an arc shorter than the arcs of the guide grooves  251 . However, the shape of the guide protrusions  234  is not limited to the illustrated embodiment. In another embodiment, the guide protrusions  234  may be formed in various shapes capable of moving in the guide grooves  251  along the arcs of the guide grooves  251 . For example, the guide protrusions  234  may be formed in a circular protrusion shape having a size that can be accommodated in the guide grooves  251 . 
     In an embodiment, the guide protrusions  234  may be formed on the inside of the opening area  233  so as to be accommodated in the guide grooves  251  of the guide member  250 . For example, the guide protrusions  234  may be formed on sidewalls  2331  and  2332  of the opening area  233 . The guide protrusions  234  may be formed on the first sidewall  2331  and/or the second sidewall  2332  facing the axial directions among sidewalls of the opening area  233 . For example, the first sidewall  2331  and the second sidewall  2332  of the opening area  233  may be defined as sidewalls substantially perpendicular to the axial directions. For example, the first sidewall  2331  and the second sidewall  2332  may face each other with the opening area  233  therebetween. For example, the guide protrusions  234  may protrude from the first sidewall  2331  toward the second sidewall  2332 , or may protrude from the second sidewall  2332  toward the first sidewall  2331 . According to the illustrated embodiment, the guide protrusions  234  may be formed on the first sidewall  2331  and the second sidewall  2332 , respectively. However, in various embodiments, the guide protrusions  234  may be formed on only one of the first sidewall  2331  and the second sidewall  2332 . 
     In an embodiment, the rotary member  230  may include a stopper  238  for limiting the range of rotation of the guide member  250 . For example, the stopper  238  may axially extend from the first sidewall  2331  to the second sidewall  2332  of the opening area  233 . The stopper  238  may be brought into contact with, or spaced apart from, the guide member  250  as the guide member  250  rotates. For example, when rotating in one direction along a predetermined path, the guide member  250  may be rotatable only until the guide member  250  makes contact with the stopper  238 . In various embodiments, the rotary member  230  may not include the stopper  238 . 
     Referring to  FIG. 14 , the guide member  250  according to an embodiment may include the guide grooves  251  in which the guide protrusions  234  of the rotary member  230  are accommodated. For example, at least parts of the guide protrusions  234  may be accommodated in the guide grooves  251  so as to be movable along the guide grooves  251 . The guide grooves  251 , together with the guide protrusions  234 , may guide a rotational path of the guide member  250 . 
     In an embodiment, the guide grooves  251  may be formed in an arc shape. For example, as the guide protrusions  234  move along the guide grooves  251  having an arc shape, the guide member  250  may rotate about the center of the arc relative to the rotary member  230 . In an embodiment, the guide member  250  may rotate about a virtual axis of rotation R 3  or R 4  relative to the rotary member  230 , and the virtual axis of rotation may be defined as the center of the arcs of the guide grooves  251 . In various embodiments, the center of the arcs of the guide grooves  251  may overlap at least part of the display  140  when the display  140  is viewed in the axial directions. A relative positional relationship between the axis of rotation of the guide member  250  and the display  140  will be described below with reference to  FIG. 20 . 
     In an embodiment, the guide grooves  251  may be formed on at least some side surfaces of the guide member  250  so as to face the axial directions. For example, the guide grooves  251  may be formed on side surfaces  252  and  253  of the guide member  250  that face the axial directions. The guide member  250  may include the first side surface  252  facing the first axial direction {circle around ( 1 )} and the second side surface  253  facing the second axial direction {circle around ( 2 )}. For example, the first side surface  252  and the second side surface  253  of the guide member  250  may be defined as side surfaces substantially perpendicular to the axial directions. For example, the second side surface  253  may be a side surface facing away from the first side surface  252 . The guide grooves  251  may be recessed from the first side surface  252  toward the second side surface  253 , or may be recessed from the second side surface  253  toward the first side surface  252 . The guide grooves  251  may be formed in a form in which one end portion is open. 
     In an embodiment, the guide member  250  may include a seating surface  254  that connects the first side surface  252  and the second side surface  253  and on which a rotary plate (e.g., the rotary plate  261  or  262  of  FIGS. 16A and 16B ) is seated, and an inclined surface  255  obliquely extending from the seating surface  254 . In an embodiment, a coupling area  256  to which the rotary plate  261  or  262  is coupled may be formed in one area of the seating surface  254 . The coupling area  256  may be recessed from another area of the seating surface  254 . For example, a coupling hole  257  for fixedly coupling the rotary plate  261  or  262  may be formed in the coupling area  256 . In an embodiment, the inclined surface  255  may extend from the seating surface  254  so as to be downwardly inclined, and the open end portions of the guide grooves  251  may be formed in at least partial areas of the inclined surface  255 . For example, the guide grooves  251  may extend in an arc shape from the partial areas of the inclined surface  255  to partial areas of the side surfaces  252  and  253  of the guide member  250 . 
     Referring to  FIG. 15 , the guide member  250  may be coupled to the inside of the opening area  233  of the rotary member  230  such that the guide protrusions  234  are accommodated in the guide grooves  251 . Accordingly, the guide member  250  may rotate relative to the rotary member  230  along an arc-shaped rotational path formed by the guide protrusions  234  and the guide grooves  251 . In the state in which the guide member  250  is accommodated in the opening area  233  of the rotary member  230 , the first side surface  252  of the guide member  250  may face the first sidewall  2331  of the opening area  233 , and the second side surface  253  of the guide member  250  may face the second sidewall  2332  of the opening area  233 . For example, the guide protrusion  234  formed on the first sidewall  2331  may be accommodated in the guide groove  251  formed on the first side surface  252 , and the guide protrusion  234  formed on the second sidewall  2332  may be accommodated in the guide groove  251  formed on the second side surface  253 . 
       FIG. 16A  is a view illustrating a coupling structure of guide members and rotary plates of a hinge structure according to an embodiment of the disclosure. 
       FIG. 16B  is a view illustrating a coupling structure of guide members and rotary plates of a hinge structure according to an embodiment of the disclosure. 
       FIG. 16A  is a plan view of the guide members and the rotary plates.  FIG. 16B  is a view of the guide members and the rotary plates of  FIG. 16A  as viewed in the first axial direction. 
     Referring to  FIGS. 16A and 16B , the hinge structure  200  according to an embodiment may include the first guide member  240 , the second guide member  250 , the first rotary plate  261 , and the second rotary plate  262 . 
     In an embodiment, the first guide member  240  may be coupled to at least a partial area of the first rotary plate  261  such that the first rotary plate  261  moves (or, rotates) together with the first guide member  240  when the first guide member  240  rotates relative to the first rotary member (e.g., the first rotary member  220  of  FIGS. 5 and 6 ). For example, the first guide member  240  and the first rotary plate  261  may be configured to integrally move through screw coupling. 
     In an embodiment, the first guide member  240  may include a first seating surface  244  to which the first rotary plate  261  is coupled and a first inclined surface  245  obliquely extending from the first seating surface  244 . For example, at least part of the first rotary plate  261  may be coupled to the first seating surface  244 . Referring to  FIGS. 16A and 16B , when the first rotary plate  261  is viewed from above, at least part of the first seating surface  244  may overlap the first rotary plate  261 , and the first inclined surface  245  may not overlap the first rotary plate  261 . 
     In an embodiment, the first guide grooves  241  having an arc shape may be formed on side surfaces  242  of the first guide member  240 . For example, the center of the arcs of the first guide grooves  241  may be defined as an axis of rotation of a rotary motion of the first guide member  240  and the first rotary plate  261 . 
     In an embodiment, the second guide member  250  may be coupled to at least a partial area of the second rotary plate  262  such that the second rotary plate  262  moves (or, rotates) together with the second guide member  250  when the second guide member  250  rotates relative to the second rotary member (e.g., the second rotary member  230  of  FIGS. 5 and 6 ). For example, the second guide member  250  and the second rotary plate  262  may be configured to integrally move through screw coupling. 
     In an embodiment, the second guide member  250  may include a second seating surface  254  to which the second rotary plate  262  is coupled and a second inclined surface  255  obliquely extending from the second seating surface  254 . For example, at least part of the second rotary plate  262  may be coupled to the second seating surface  254 . Referring to  FIGS. 16A and 16B , when the second rotary plate  262  is viewed from above, at least part of the second seating surface  254  may overlap the second rotary plate  262 , and the second inclined surface  255  may not overlap the second rotary plate  262 . 
     In an embodiment, the second guide grooves  251  having an arc shape may be formed on side surfaces  252  of the second guide member  250 . For example, the center of the arcs of the second guide grooves  251  may be defined as an axis of rotation of a rotary motion of the second guide member  250  and the second rotary plate  262 . 
     In an embodiment, the first rotary plate  261  may include the first support portion  261   a  extending in the axial directions, and the second support portions  261   b  and the third support portion  261   c  that extend from the first support portion  261   a  in the direction perpendicular to the axial directions and that are spaced apart from each other in the axial directions. For example, the second support portions  26   1   b  may extend from the opposite axial end portions of the first support portion  261   a , and the third support portion  261   c  may extend from one area of the first support portion  261   a  so as to be located between the second support portions  26   1   b.  For example, the first guide members  240  may be coupled to the opposite axial end portions of the first support portion  261   a.  For example, openings (not illustrated) for screw coupling may be formed in the opposite axial end portions of the first support portion  261   a.  The openings may overlap coupling holes (e.g., the coupling hole  257  in the coupling area  256  of  FIG. 14 ) that are formed in the first seating surfaces  244 . 
     In an embodiment, the second rotary plate  262  may include the fourth support portion  262   a  extending in the axial directions, and the fifth support portions  262   b  and the sixth support portion  262   c  that extend from the fourth support portion  262   a  in the direction perpendicular to the axial directions and that are spaced apart from each other in the axial directions. For example, the fifth support portions  262   b  may extend from the opposite axial end portions of the fourth support portion  262   a , and the sixth support portion  262   c  may extend from one area of the fourth support portion  262   a  so as to be located between the fifth support portions  262   b.  For example, the second guide members  250  may be coupled to the opposite axial end portions of the fourth support portion  262   a.  For example, openings (not illustrated) for screw coupling may be formed in the opposite axial end portions of the fourth support portion  262   a.  The openings may overlap coupling holes (e.g., the coupling hole  257  in the coupling area  256  of  FIG. 14 ) that are formed in the second seating surfaces  254 . 
     Hereinafter, an operation in which the guide members  240  and  250  and the rotary plates  261  and  262  rotate relative to the rotary members  220  and  230  by a repulsive force of the display  140  in a folding motion will be described with reference to  FIGS. 17, 18A, 18B, 19, and 20 . 
       FIG. 17  is a view illustrating folding axes of a display of an electronic device according to an embodiment of the disclosure. 
       FIG. 17  illustrates the shape of the display when the electronic device is in an unfolded state or a fully folded state. For example, the display illustrated by dotted lines in  FIG. 17  represents the shape of the display when the electronic device is in the unfolded state. 
     Referring to  FIG. 17 , the electronic device  100  according to an embodiment may include the first housing  110 , the second housing  120 , the display  140 , the first rotary plate  261 , and the second rotary plate  262 . For example,  FIG. 17  may be a sectional view of the electronic device (e.g., the electronic device  100  of  FIG. 2C ) taken along line S-S′ illustrated in  FIG. 2C , and repetitive descriptions will hereinafter be omitted. 
     In an embodiment, when the housings  110  and  120  are folded, the display  140  may be folded as at least partial areas of the display  140  move together with the housings  110  and  120 . For example, the display  140  may include the first area  141  disposed on the first housing  110 , the second area  142  disposed on the second housing  120 , and the folding area  143  located between the first area  141  and the second area  142 . In an embodiment, the first area  141  may be attached to at least part of the first housing  110 , and the second area  142  may be attached to at least part of the second housing  120 . For example, the first area  141  may move together with the first housing  110  when the first housing  110  is folded or unfolded. The second area  142  may move together with the second housing  120  when the second housing  120  is folded or unfolded. For example, the folding area  143  may partially form a curved surface or a flat surface as the first housing  110  and the second housing  120  are folded or unfolded. 
     In an embodiment, the folding area  143  of the display may include a portion (e.g., a variable area  144   a  of the in-folding area  144  or the out-folding area  145  and  146  of  FIG. 20 ) that deforms to be curved or flat while being folded when the first housing  110  and the second housing  120  are folded or unfolded, and a portion (e.g., non-variable areas  144   b  and  144   c  of the in-folding area  144  of  FIG. 20 ) that remains substantially flat without being folded. The variable area  144   a  and the non-variable areas  144   b  and  144   c  of the in-folding area  144  will be described below with reference to  FIG. 20 . 
     In an embodiment, the display  140  may generate a repulsive force RF in a folding motion. For example, the repulsive force RF may be generated from the folding area  143  as the folding area  143  forms a curved surface when the folding motion is performed. In an embodiment, the repulsive force RF may act on the first rotary plate  261  and the second rotary plate  262 . For example, the repulsive force RF may push the first rotary plate  261  and the second rotary plate  262  in opposite directions. The first rotary plate  261  and the second rotary plate  262  may rotate along arc-shaped rotational paths by the repulsive force RF (e.g., refer to  FIGS. 18A and 18B ) and may thus support the display  140  such that the display  140  forms a specific shape (e.g., a water-drop shape or a jar shape). 
     In an embodiment, as illustrated in  FIG. 17 , in the fully folded state, the display  140  may be supported by the rotary plates  261  and  262  such that the display  140  pushes the rotary plates  261  and  262  by the repulsive force RF to form a specific shape. For example, in the fully folded state, different regions of the folding area  143  of the display  140  may be partially curved. 
     In an embodiment, the folding area  143  of the display  140  may include the in-folding area  144 , the first out-folding area  145  located between the first area  141  and the in-folding area  144 , and the second out-folding area  146  located between the second area  142  and the in-folding area  144 . For example, the folding area  143  may be configured such that in the unfolded state, the in-folding area  144  and the out-folding areas  145  and  146  form substantially the same plane as the first area  141  and the second area  142 . For example, the folding area  143  may be configured such that in a folded state, the in-folding area  144  and the out-folding areas  145  and  146  are partially curved. Referring to  FIG. 17 , in the fully folded state, the in-folding area  144  and the out-folding areas  145  and  146  may be folded so that the display  140  may be formed in a water-drop shape or a jar shape. 
     In an embodiment, the display  140  may include a first surface  140   a  forming the outer surface (or, the front surface) of the electronic device  100  in the unfolded state and a second surface  140   b  facing away from the first surface  140   a.  For example, the first surface  140   a  may refer to the surface exposed outside the electronic device  100  in the unfolded state, and the second surface  140   b  may refer to the rear surface of the display  140 . For example, the second surface  140   b  may refer to the surface to which the first housing  110 , the second housing  120 , the first rotary plate  261 , and the second rotary plate  262  are attached. 
     In an embodiment, the in-folding area  144  may refer to the area where the display  140  is folded inward, and the out-folding areas  145  and  146  may refer to the areas where the display  140  is folded outward. For example, the in-folding area  144  may be defined as an area where one area and another area of the first surface  140   a  are folded toward each other. The out-folding areas  145  and  146  may be defined as areas where one area and another area of the second surface  140   b  are folded toward each other. 
     In an embodiment, in the fully folded state, at least part of the in-folding area  144  may form a curved surface whose center of curvature coincides with a first folding axis F 1 . In an embodiment, in the fully folded state, at least part of the first out-folding area  145  may form a curved surface whose center of curvature coincides with a second folding axis F 2 . In an embodiment, in the fully folded state, at least part of the second out-folding area  146  may form a curved surface whose center of curvature coincides with a third folding axis F 3 . For example, in the fully folded state, the curvature of the curved surface of the in-folding area  144  may be greater than the curvatures of the curved surfaces of the out-folding areas  145  and  146 . 
     As illustrated in  FIG. 17 , in the fully folded state, the distance r 1  between the curved surface of the in-folding area  144  and the first folding axis F 1  may be the minimum radius of curvature of the in-folding area  144 . In the fully folded state, the distance r 2  between the curved surface of the first out-folding area  145  and the second folding axis F 2  may be the minimum radius of curvature of the first out-folding area  145 . In the fully folded state, the distance r 3  between the curved surface of the second out-folding area  146  and the third folding axis F 3  may be the minimum radius of curvature of the second out-folding area  146 . For example, the minimum radius of curvature r 1  of the in-folding area  144  may be smaller than the minimum radii of curvature r 2  and r 3  of the out-folding areas  145  and  146 . The minimum radius of curvature r 2  of the first out-folding area  145  may be substantially the same as the minimum radius of curvature r 3  of the second out-folding area  146 . 
     In an embodiment, the first folding axis Fl may be located in the direction toward the first surface  140   a  with respect to the display  140 , and the second folding axis F 2  and the third folding axis F 3  may be located in the direction toward the second surface  140   b  with respect to the display  140 . For example, when the electronic device  100  is in the unfolded state, the display  140  may be configured such that the first folding axis F 1  is located in the +z-axis direction from the first surface  140   a  and the second folding axis F 2  and the third folding axis F 3  are located in the −z-axis direction from the second surface  140   b.  For example, the distance by which the first folding axis F 1  is spaced apart from the first surface  140   a  in the +z-axis direction may be smaller than the distances by which the second folding axis F 2  and the third folding axis F 3  are spaced apart from the second surface  140   b  in the −z-axis direction. 
     According to the embodiment illustrated in  FIG. 17 , in the fully folded state, the first area  141  and the second area  142  of the display  140  may be disposed to face each other in parallel. For example, in the fully folded state, the first area  141  and the second area  142  may extend parallel to each other in the z-axis direction from the opposite end portions of the folding area  143 . For example, the first area  141  and the second area  142  may extend parallel to each other in the state of being spaced apart from each other by a specified gap (e.g., gap G of  FIG. 20 ) in the direction perpendicular to the edges P 3  and P 4  of the housings  110  and  120 . 
     The electronic device  100  according to an embodiment may be configured such that in the fully folded state, the in-folding area  144  and the out-folding areas  145  and  146  of the display  140  are folded about the folding axes Fl, F 2 , and F 3 , respectively, and the first area  141  and the second area  142  extend parallel to each other. Accordingly, in the fully folded state, the curvature of the folding area  143  may be made smaller than a specified value so that a fold in the folding area  143  may be improved, and as the first area  141  and the second area  142  extend parallel to each other, the third edge P 3  of the first housing  110  and the fourth edge P 4  of the second housing  120  may completely make contact with each other such that a gap is not generated therebetween. 
       FIG. 18A  is a view illustrating a display, rotary members, guide members, and rotary plates of an electronic device according to an embodiment of the disclosure. 
       FIG. 18B  is a view illustrating a display, rotary members, guide members, and rotary plates of an electronic device according to an embodiment of the disclosure. 
       FIG. 19  is a view illustrating a rotary motion of guide members of a hinge structure according to an embodiment of the disclosure. 
       FIGS. 18A and 18B  illustrate an operation in which in a folding motion, the rotary plates and the guide members are rotated by a repulsive force of the display.  FIG. 19  illustrates an operation in which in the folding motion, the guide protrusions of the guide members rotate along specified paths in the guide grooves of the rotary members. 
       FIG. 18A  illustrates an operation in which the guide members rotate relative to the rotary members when the rotary members rotate and may be a view in which the rotary plates are omitted.  FIG. 18B  illustrates a rotary motion of the guide members and the rotary plates and may be a view in which the rotary members are omitted. The sectional views of the rotary members and the guide members illustrated in  FIG. 19  may be sectional views taken along lines D-D′ in  FIG. 19 . 
     Referring to  FIGS. 18A, 18B, and 19 , the hinge structure  200  according to an embodiment may include the first rotary member  220 , the second rotary member  230 , the first guide member  240 , the second guide member  250 , the first rotary plate  261 , and the second rotary plate  262 . 
     In an embodiment, the first guide member  240  and the first rotary plate  261  may be configured to rotate about the third axis of rotation R 3  by the repulsive force (e.g., the repulsive force RF of  FIG. 17 ) of the display  140 . In an embodiment, the second guide member  250  and the second rotary plate  262  may be configured to rotate about the fourth axis of rotation R 4  by the repulsive force of the display  140 . 
     In an embodiment, in the folding motion of the electronic device  100 , the first rotary member  220  may rotate about the first axis of rotation R 1  in the first rotational direction (e.g., the clockwise direction, based on  FIGS. 18A and 18B ). In the folding motion, the first rotary plate  261  and the first guide member  240  may rotate about the third axis of rotation R 3  in the first rotational direction by the repulsive force of the display  140 . For example, a repulsive force generated from the folding area  143  as the folding area  143  is folded in the folding motion may be transmitted to the first rotary plate  261 . The first rotary plate  261  may be coupled to integrally move together with the first guide member  240  (e.g., refer to  FIGS. 16A and 16B ), and the first guide member  240  may rotate about the third axis of rotation R 3  along a specified path relative to the first rotary member  220  by the repulsive force transmitted to the first rotary plate  261 . 
     In an embodiment, the third axis of rotation R 3  and/or the rotational path of the first guide member  240  may be formed by the first guide grooves  241  of the first guide member  240 . In an embodiment, the first guide grooves  241  may be formed in a substantially arc shape. The center of the arcs of the first guide grooves  241  may form the third axis of rotation R 3  of the first guide member  240 . For example, the third axis of rotation R 3  may be parallel to the first axis of rotation R 1 . 
     In an embodiment, the third axis of rotation R 3  may be located on the display  140 . For example, the third axis of rotation R 3  may be located in at least a partial area of the display  140  when the electronic device  100  is viewed in the axial directions. For example, the third axis of rotation R 3  may be located between the opposite surfaces of the display  140  in the thickness direction. Based on  FIGS. 18A and 18B , the third axis of rotation R 3  may be located between a first surface (e.g., the front surface, the upper surface, or the first surface  140   a  of  FIG. 20 ) and a second surface (e.g., the rear surface, the lower surface, or the second surface  140   b  of  FIG. 20 ) of the display  140 . For example, the third axis of rotation R 3  may pass through at least part of the display  140  in the axial directions. For example, the third axis of rotation R 3  may overlap the display  140  when the cross-section of the display  140  is viewed. For example, in an unfolded state, the third axis of rotation R 3  may be located in the +z-axis direction with respect to the first rotary plate  261 . For example, in the unfolded state, the third axis of rotation R 3  may be located in a higher position in the +z-axis direction than the first axis of rotation R 1 . 
     In an embodiment, in the folding motion of the electronic device  100 , the second rotary member  230  may rotate about the second axis of rotation R 2  in the second rotational direction (e.g., the counterclockwise direction, based on  FIGS. 18A and 18B ). In the folding motion, the second rotary plate  262  and the second guide member  250  may rotate about the fourth axis of rotation R 4  in the second rotational direction by the repulsive force of the display  140 . For example, the repulsive force generated from the folding area  143  as the folding area  143  is folded in the folding motion may be transmitted to the second rotary plate  262 . The second rotary plate  262  may be coupled to integrally move together with the second guide member  250  (e.g., refer to  FIGS. 16A and 16B ), and the second guide member  250  may rotate about the fourth axis of rotation R 4  in the second rotational direction (e.g., the counterclockwise direction) relative to the second rotary member  230  by the repulsive force transmitted to the second rotary plate  262 . 
     In an embodiment, the fourth axis of rotation R 4  and/or the rotational path of the second guide member  250  may be formed by the second guide grooves  251  of the second guide member  250 . In an embodiment, the second guide grooves  251  may be formed in a substantially arc shape. The center of the arcs of the second guide grooves  251  may form the fourth axis of rotation R 4  of the second guide member  250 . For example, the fourth axis of rotation R 4  may be parallel to the second axis of rotation R 2 . 
     In an embodiment, the fourth axis of rotation R 4  may be located on the display  140 . For example, the fourth axis of rotation R 4  may be located in at least a partial area of the display  140  when the electronic device  100  is viewed in the axial directions. For example, the fourth axis of rotation R 4  may be located between the opposite surfaces of the display  140  in the thickness direction. Based on  FIGS. 18A and 18B , the fourth axis of rotation R 4  may be located between the first surface (e.g., the front surface, the upper surface, or the first surface  140   a  of  FIG. 20 ) and the second surface (e.g., the rear surface, the lower surface, or the second surface  140   b  of  FIG. 20 ) of the display  140 . For example, the fourth axis of rotation R 4  may pass through at least part of the display  140  in the axial directions. For example, the fourth axis of rotation R 4  may overlap the display  140  when the cross-section of the display  140  is viewed. For example, in the unfolded state, the fourth axis of rotation R 4  may be located in the +z-axis direction with respect to the second rotary plate  262 . For example, in the unfolded state, the fourth axis of rotation R 4  may be located in a higher position in the +z-axis direction than the second axis of rotation R 2 . 
     In an embodiment, when folding and unfolding motions are performed, the rotational direction of the first rotary member  220  and the rotational direction of the second rotary member  230  may be opposite to each other. Furthermore, when the folding and unfolding motions are performed, the rotational direction of the first guide member  240  and the first rotary plate  261  and the rotational direction of the second guide member  250  and the second rotary plate  262  may be opposite to each other. 
     Referring to  FIG. 19 , the guide protrusions  224  and  234  of the rotary members  220  and  230  may relatively slide in the guide grooves  241  and  251  of the guide members  240  and  250  as the guide members  240  and  250  rotate about the axes of rotation R 3  and R 4 . For example, the rotational paths of the rotary members  220  and  230  may be defined as paths along which the guide protrusions  224  and  234  move in the arc-shaped guide grooves  241  and  251 .  FIG. 19  may be a view illustrating an operation in which the guide members  240  and  250  rotate about the axes of rotation R 3  and R 4  in the opening areas  223  and  233 . 
     In an embodiment, the first guide member  240  may be coupled to the first rotary member  220  so as to be rotatable about the third axis of rotation R 3  in the first opening area  223 . The first guide member  240  may rotate about the third axis of rotation R 3  relative to the first rotary member  220  in the state in which the first guide protrusions  224  of the first rotary member  220  are accommodated in the first guide grooves  241 . For example, when the display  140  is folded or unfolded, the first guide member  240  may rotate by a specified range along an arc-shaped rotational path whose center coincides with the third axis of rotation R 3 . 
     In an embodiment, when the display  140  is folded, the first guide member  240  may rotate about the third axis of rotation R 3  in the first rotational direction (e.g., the clockwise direction, based on  FIG. 19 ) (e.g., may rotate in the direction of an arrow in the left-side sectional view of  FIG. 19 ). Accordingly, when the cross-section of the first rotary member  220  and the first guide member  240  is viewed, the first guide protrusions  224  may be seen to relatively rotate in the second rotational direction (e.g., the counterclockwise direction, based on  FIG. 19 ) opposite to the first rotational direction in the first guide grooves  241 . In an embodiment, when the display  140  is unfolded, the first guide member  240  may rotate about the third axis of rotation R 3  in the second rotational direction (e.g., the counterclockwise direction, based on  FIG. 19 ) (e.g., may operate in the direction opposite to that of the arrow in the left-side sectional view of  FIG. 19 ). 
     In various embodiments, the first guide member  240  may rotate until part of the first guide member  240  makes contact with the stopper  228  of the first rotary member  220 . For example, the rotation of the first guide member  240  in the first rotational direction may be limited by the contact with the stopper  228 , and the first rotary plate  261 , while resisting the repulsive force of the display  140 , may support the display  140  such that the display  140  forms a specific shape. 
     In an embodiment, the second guide member  250  may be coupled to the second rotary member  230  so as to be rotatable about the fourth axis of rotation R 4  in the second opening area  233 . The second guide member  250  may rotate about the fourth axis of rotation R 4  relative to the second rotary member  230  in the state in which the second guide protrusions  234  of the second rotary member  230  are accommodated in the second guide grooves  251 . For example, when the display  140  is folded or unfolded, the second guide member  250  may rotate by a specified range along an arc-shaped rotational path whose center coincides with the fourth axis of rotation R 4 . 
     In an embodiment, when the display  140  is folded, the second guide member  250  may rotate about the fourth axis of rotation R 4  in the second rotational direction (e.g., the counterclockwise direction, based on  FIG. 19 ) (e.g., may operate in the direction of an arrow in the right-side sectional view of  FIG. 19 ). Accordingly, when the cross-section of the second rotary member  230  and the second guide member  250  is viewed, the second guide protrusions  234  may be seen to relatively rotate in the first rotational direction (e.g., the clockwise direction, based on  FIG. 19 ) opposite to the second rotational direction in the second guide grooves  251 . In an embodiment, when the display  140  is unfolded, the second guide member  250  may rotate about the fourth axis of rotation R 4  in the first rotational direction (e.g., the clockwise direction) (e.g., may operate in the direction opposite to that of the arrow in the right-side sectional view of  FIG. 19 ). 
     In various embodiments, the second guide member  250  may rotate until part of the second guide member  250  makes contact with the stopper  238  of the second rotary member  230 . For example, the rotation of the second guide member  250  in the second rotational direction may be limited by the contact with the stopper  238 , and the second rotary plate  262 , while resisting the repulsive force of the display  140 , may support the display  140  such that the display  140  forms a specific shape. 
     According to the illustrated embodiment, the guide protrusions  224  and  234  may be formed on the rotary members  220  and  230 , and the guide grooves  241  and  251  may be formed on the guide members  240  and  250 . However, the positions of the guide protrusions  224  and  234  and the guide grooves  241  and  251  are not limited to the illustrated embodiment. In various embodiments, the guide protrusions  224  and  234  may be formed on the guide members  240  and  250 , and the guide grooves  241  and  251  may be formed on the rotary members  220  and  230 . 
       FIG. 20  is a view illustrating axes of rotation of guide members and rotary plates of a hinge structure according to an embodiment of the disclosure. 
     Referring to  FIG. 20 , the hinge structure  200  according to an embodiment may be configured such that the guide members  240  and  250  and the rotary plates  261  and  262  rotate about virtual axes of rotation (e.g., the third axis of rotation R 3  and the fourth axis of rotation R 4 ). 
     In an embodiment, the third axis of rotation R 3  may be defined as the center of a rotary motion of the first guide member  240  and the first rotary plate  261 . The third axis of rotation R 3  may refer to a virtual axis formed by the first guide grooves  241  having an arc shape. For example, the third axis of rotation R 3  may be defined as the center of the arcs of the arc-shaped first guide grooves  241 . For example, the first guide member  240  and the first rotary plate  261  may rotate in a predetermined range along an arc-shaped rotational path whose center coincides with the third axis of rotation R 3 . 
     In an embodiment, the third axis of rotation R 3  may be located between the opposite surfaces of the display  140  in the thickness direction. For example, the third axis of rotation R 3  may be located between the first surface  140   a  and the second surface  140   b  of the display  140 . In an embodiment, the third axis of rotation R 3  may be formed in a position substantially overlapping the display  140 . For example, when the cross-section of the display  140  is viewed, the third axis of rotation R 3  may overlap at least a partial area (e.g., the folding area  143 ) of the display  140 . For example, the third axis of rotation R 3  may be seen to pass through at least a partial area of the display  140  in a direction parallel to the axial directions. 
     In an embodiment, the fourth axis of rotation R 4  may be defined as the center of a rotary motion of the second guide member  250  and the second rotary plate  262 . The fourth axis of rotation R 4  may refer to a virtual axis formed by the second guide grooves  251  having an arc shape. For example, the fourth axis of rotation R 4  may be defined as the center of the arcs of the arc-shaped second guide grooves  251 . For example, the second guide member  250  and the second rotary plate  262  may rotate in a predetermined range along an arc-shaped rotational path whose center coincides with the fourth axis of rotation R 4 . 
     In an embodiment, the third axis of rotation R 3  may be located between the opposite surfaces of the display  140  in the thickness direction. For example, the fourth axis of rotation R 4  may be located between the first surface  140   a  and the second surface  140   b  of the display  140 . In an embodiment, the fourth axis of rotation R 4  may be formed in a position substantially overlapping the display  140 . For example, when the cross-section of the display  140  is viewed, the fourth axis of rotation R 4  may overlap at least a partial area (e.g., the folding area  143 ) of the display  140 . For example, the fourth axis of rotation R 4  may be seen to pass through at least a partial area of the display  140  in a direction parallel to the axial directions. 
     In an embodiment, the third axis of rotation R 3  and the fourth axis of rotation R 4  may overlap different regions of the folding area  143  of the display  140 . For example, the display  140  may include the first area  141 , the second area  142 , and the folding area  143  located between the first area  141  and the second area  142 . The folding area  143  may include the in-folding area  144 , the first out-folding area  145  located between the first area  141  and the in-folding area  144 , and the second out-folding area  146  located between the second area  142  and the in-folding area  144 . In an embodiment, the third axis of rotation R 3  may overlap at least part of the first out-folding area  145  when the cross-section of the display  140  is viewed. In an embodiment, the fourth axis of rotation R 4  may overlap at least part of the second out-folding area  146  when the cross-section of the display  140  is viewed. 
     According to the embodiment illustrated in  FIG. 20 , the in-folding area  144  of the display  140  may be configured such that in folding and unfolding motions, one portion deforms to be curved or flat and the other portions remain flat. 
     In an embodiment, the in-folding area  144  of the display  140  may include the variable area  144   a  that deforms to be curved or flat in response to folding and unfolding motions, and the first non-variable area  144   b  and the second non-variable area  144   c  that extend from the opposite end portions of the variable area  144   a  and remain flat. For example, the first non-variable area  144   b  may be defined as an area between the first out-folding area  145  and the variable area  144   a.  For example, the second non-variable area  144   c  may be defined as an area between the second out-folding area  146  and the variable area  144   a.  The variable area  144   a  may form a curved surface having a predetermined curvature in a folded state and may form a flat surface in an unfolded state. The first non-variable area  144   b  and the second non-variable area  144   c  may remain flat in the folded state and the unfolded state. 
     In an embodiment, the variable area  144   a  may be spaced apart from, or brought into contact with, the first rotary plate  261  and the second rotary plate  262  depending on folding and unfolding motions. For example, in an unfolded state, the variable area  144   a  may be brought into contact with the first rotary plate  261  and the second rotary plate  262  and may be supported by the first rotary plate  261  and the second rotary plate  262  accordingly. For example, in a folding motion, the variable area  144   a  may deform to be curved while being spaced apart from the first rotary plate  261  and the second rotary plate  262 . For example, the variable area  144   a  may not be attached to the first rotary plate  261  and the second rotary plate  262 . 
     In an embodiment, at least part of the first rotary plate  261  may be attached to the first non-variable area  144   b.  For example, the first non-variable area  144   b  may move together with the first rotary plate  261 . For example, the display  140  may be configured such that in folding and unfolding motions, the first non-variable area  144   b  rotates about the third axis of rotation R 3  relative to the first area  141  as the third axis of rotation R 3  of the first guide member  240  and the first rotary plate  261  is located in the first out-folding area  145 . For example, the first non-variable area  144   b  may form an angle of 180 degrees with the first area  141  in an unfolded state and may form an angle of less than 180 degrees with the first area  141  in a fully folded state. 
     In an embodiment, at least part of the second rotary plate  262  may be attached to the second non-variable area  144   c.  For example, the second non-variable area  144   c  may move together with the second rotary plate  262 . For example, the display  140  may be configured such that in folding and unfolding motions, the second non-variable area  144   c  rotates about the fourth axis of rotation R 4  relative to the second area  142  as the fourth axis of rotation R 4  of the second guide member  250  and the second rotary plate  262  is located in the second out-folding area  146 . For example, the second non-variable area  144   c  may form an angle of 180 degrees with the second area  142  in an unfolded state and may form an angle of less than 180 degrees with the second area  142  in a fully folded state. 
     In an embodiment, the first out-folding area  145  may be defined between the first area  141  and the first non-variable area  144   b.  The first out-folding area  145  may be an area, which is the basis of relative rotation between the first area  141  and the first non-variable area  144   b  in folding and unfolding motions. For example, in response to rotation between the first area  141  and the first non-variable area  144   b , the first out-folding area  145  may form a flat surface, or may form, in at least part thereof, a curved surface having a predetermined curvature. For example, as at least part of the first out-folding area  145  forms a curved surface, the first area  141  and the first non-variable area  144   b  may form an angle of less than 180 degrees. The length of the first out-folding area  145  may remain substantially the same in folding and unfolding motions. 
     In an embodiment, the second out-folding area  146  may be defined between the second area  142  and the second non-variable area  144   c.  The second out-folding area  146  may be an area, which is the basis of relative rotation between the second area  142  and the second non-variable area  144   c  in folding and unfolding motions. For example, in response to rotation between the second area  142  and the second non-variable area  144   c , the second out-folding area  146  may form a flat surface, or may form, in at least part thereof, a curved surface having a predetermined curvature. For example, as at least part of the second out-folding area  146  forms a curved surface, the second area  142  and the second non-variable area  144   c  may form an angle of less than 180 degrees. The length of the second out-folding area  146  may remain substantially the same in folding and unfolding motions. 
       FIG. 21A  is a view illustrating adhesive areas and non-adhesive areas of a display of an electronic device according to an embodiment of the disclosure. 
       FIG. 21B  is a view illustrating adhesive areas and non-adhesive areas of a display of an electronic device according to an embodiment of the disclosure. 
       FIGS. 21A and 21B  illustrate an area where the display is attached with other components of the electronic device, and  FIG. 21A  may be a view in which the display is omitted. 
     Referring to  FIGS. 21A and 21B , the electronic device  100  according to an embodiment may be configured such that at least a partial area of the display  140  is attached to part of the housings  110  and  120  and part of the hinge structure  200 . For example, the display  140  may be attached to the housings  110  and  120  and the hinge structure  200  through an adhesive member (e.g., a tape). 
     In an embodiment, the display  140  may be attached to the first plate  111  of the first housing  110 , the second plate  121  of the second housing  120 , the first support portion  261   a  of the first rotary plate  261 , the fourth support portion  262   a  of the second rotary plate  262 , the first fixed plate  263 , and the second fixed plate  264 . 
     In an embodiment, a plurality of adhesive areas (e.g., shaded portions in  FIG. 21A ) spaced apart from each other in the direction perpendicular to the axial directions may be defined in the electronic device  100 . For example, an adhesive area AA may include a first adhesive area AA 1  overlapping the first plate  111  and the first fixed plate  263 , a second adhesive area AA 2  overlapping the second plate  121  and the second fixed plate  264 , a third adhesive area AA 3  overlapping the first support portion  261   a  of the first rotary plate  261 , and a fourth adhesive area AA 4  overlapping the fourth support portion  262   a  of the second rotary plate  262 . For example, the adhesive area AA may refer to the area where an adhesive member  191  is disposed. 
     In an embodiment, the display  140  may be attached to the first adhesive area AA 1 , the second adhesive area AA 2 , the third adhesive area AA 3 , and the fourth adhesive area AA 4 . For example, the first area  141  of the display  140  may be attached to the first adhesive area AA 1 . For example, the second area  142  of the display  140  may be attached to the second adhesive area AA 2 . For example, the first non-variable area  144   b  of the folding area  143  of the display  140  may be attached to the third adhesive area AA 3 . For example, the second non-variable area  144   c  of the folding area  143  of the display  140  may be attached to the fourth adhesive area AA 4 . 
     In an embodiment, a first non-adhesive area NAA 1  may be defined between the first adhesive area AA 1  and the third adhesive area AA 3 . The first non-adhesive area NAA 1  may overlap the first out-folding area  145  of the folding area  143  of the display  140 . For example, the first out-folding area  145  may remain unattached to the housings  110  and  120  or the hinge structure  200  and may deform to be curved or flat in folding and unfolding motions of the electronic device  100  accordingly (e.g., refer to  FIG. 20 ). For example, the third axis of rotation R 3  may overlap the first non-adhesive area NAA 1  when the display  140  or the first plate  111  is viewed from above. 
     In an embodiment, a second non-adhesive area NAA 2  may be defined between the second adhesive area AA 2  and the fourth adhesive area AA 4 . The second non-adhesive area NAA 2  may overlap the second out-folding area  146  of the folding area  143  of the display  140 . For example, the second out-folding area  146  may remain unattached to the housings  110  and  120  or the hinge structure  200  and may deform to be curved or flat in folding and unfolding motions of the electronic device  100  accordingly (e.g., refer to  FIG. 20 ). For example, the fourth axis of rotation R 4  may overlap the second non-adhesive area NAA 2  when the display  140  or the first plate  121  is viewed from above. 
     In an embodiment, a third non-adhesive area NAA 3  may be defined between the third adhesive area AA 3  and the fourth adhesive area AA 4 . The third non-adhesive area NAA 3  may be an area that overlaps the second support portions  26   1   b  and the third support portion  261   c  of the first rotary plate  261  and the fifth support portions  262   b  and the sixth support portion  262   c  of the second rotary plate  262 . The third non-adhesive area NAA 3  may overlap the variable area  144   a  of the in-folding area  144  in the folding area  143  of the display  140 . For example, the variable area  144   a  of the in-folding area  144  may remain unattached to the hinge structure  200  and may deform to be curved or flat in folding and unfolding motions of the electronic device  100  accordingly (e.g., refer to  FIG. 20 ). 
     As illustrated in  FIGS. 21A and 21B , the adhesive member  191  may be attached to the rear surface of the first area  141 , the rear surface of the second area  142 , and the rear surface of the non-variable area  144   a  of the in-folding area  144  of the display  140 . The adhesive member  191  may not be disposed on the rear surfaces of the out-folding areas  145  and  146  and the rear surface of the variable area  144   a  of the in-folding area  144  of the display  140 . 
     According to an embodiment, in folding and unfolding motions, the lengths of the out-folding areas  145  and  146  of the display  140  may remain constant without being changed (e.g., refer to  FIG. 20 ), and thus the non-variable area  144   a  of the folding area  143  may be attached to the third adhesive area AA 3  (e.g., the first support portion  261   a  of the first rotary plate  261 ) and the fourth adhesive area AA 4  (e.g., the second support portion  261   b  of the second rotary plate  262 ) through the adhesive member  191 . Accordingly, an area to which the flexible display  140  is attached may increase, and when the electronic device  100  is folded or unfolded, the display  140  may be firmly and stably supported. 
       FIG. 22  is a view illustrating a display module and a guide member of an electronic device according to an embodiment of the disclosure. 
     Referring to  FIG. 22 , the guide member  250  of the electronic device  100  according to an embodiment may be formed in a shape corresponding to the shape of the display  140  in a fully folded state. For example, one surface of the guide member  250  may be formed to have an angle substantially corresponding to the angle formed by the display  140  such that in the fully folded state, collision and/or interference does not occur between the guide member  250  and the display  140  (e.g., in a portion E of  FIG. 22 ) and the display  140  is stably supported. 
     The guide member  250  illustrated in  FIG. 22  may be referred to as the second guide member  250 . However, contents to be described below with reference to  FIG. 22  may be identically applied to the first guide member  240 . 
     In an embodiment, the guide member  250  may include the seating surface  254  on which the rotary plate (e.g., the rotary plate  261  or  262  of  FIGS. 16A and 16B ) is seated and the inclined surface  255  obliquely extending from the seating surface  254  at a specified angle. For example, a first virtual extension line EL 1  extending from the seating surface  254  and a second virtual extension line EL 2  extending from the inclined surface  255  may be defined to describe the angle between the inclined surface  255  and the seating surface  254 . For example, the first virtual extension line EL 1  and the second virtual extension line EL 2  may form a first included angle A 1  that is an acute angle. 
     In an embodiment, in the fully folded state, the second area  142  of the display  140  may form a predetermined angle with the second non-variable area  144   c  of the folding area  143 . For example, a third virtual extension line EL 3  extending from the second area  142  and a fourth virtual extension line EL 4  extending from the second variable area  144   a  may be defined to describe the angle formed by the second area  142  and the second non-variable area  144   c  in the fully folded state. For example, the third virtual extension line EL 3  and the fourth virtual extension line EL 4  may form a second included angle A 2  that is an acute angle. For example, the angle formed by the first area  141  and the first non-variable area  144   b  may be equal to the second included angle A 2 . For example, the first included angle A 1  and the second included angle A 2  may range from about 10 degrees to about 20 degrees and may preferably be about 15 degrees. However, the first included angle A 1  and the second included angle A 2  are not limited to the aforementioned range. 
     In various embodiments, the first included angle A 1  and the second included angle A 2  may be substantially the same as each other. For example, as illustrated in  FIGS. 21A and 21B , in the fully folded state, the seating surface  254  of the second guide member  250  may be parallel to the second non-variable area  144   c , and the inclined surface  255  of the second guide member  250  may be parallel to the second area  142 . 
     In another embodiment, the first included angle A 1  may be different from the second included angle A 2 . For example, the first included angle A 1  may be formed to be larger than the second included angle A 2 . For example, the distance between the second area  142  and the inclined surface  255  may increase in the z-axis direction. Accordingly, in the fully folded state, the inclined surface  255  of the second guide member  250  may be prevented from colliding with the second area  142  of the display  140 . 
       FIG. 23  is a view illustrating the fixed plates of the hinge structure according to an embodiment of the disclosure. 
     Referring to  FIG. 23 , the hinge structure  200  according to an embodiment may include the first rotary member  220 , the second rotary member  230 , the first guide member  240 , the second guide member  250 , the first fixed plate  263 , and the second fixed plate  264 . 
     In an embodiment, the first fixed plate  263  may be fixedly disposed on the first plate  111  of the first housing  110 . For example, the first fixed plate  263  may be fixed to a partial area of the first plate  111  through screw coupling. In an embodiment, the first fixed plate  263 , together with the first plate  111 , may support at least a partial area of the display (e.g., the display  140  of  FIG. 1 ). 
     In an embodiment, the first fixed plate  263  may support the rear surface of the display  140  to prevent the display  140  from being sunk or recessed toward the first rotary member  220  and the first guide member  240 . For example, the first fixed plate  263  may be coupled to the first plate  111  so as to overlap at least part of the first rotary member  220  and at least part of the first guide member  240 . 
     According to the illustrated embodiment, the first fixed plate  263  may overlap at least part of the first rotary member  220  and at least part of the first guide member  240  when the first plate  111  is viewed from above. For example, the first fixed plate  263  may overlap the portions where the first guide protrusions  224  are coupled to the first guide grooves (not illustrated) and may thus prevent the first guide member  240  from colliding and interfering with the display  140  when rotating about the third axis of rotation R 3 . 
       FIG. 23  may be a view in which the display  140  is omitted. However, in the case where the display  140  is disposed on the first plate  111 , the first fixed plate  263  may be disposed between at least part of the first guide member  240  and a partial area of the display  140  when the electronic device  100  is viewed in the axial directions. 
     In an embodiment, the second fixed plate  264  may be fixedly disposed on the second plate  121  of the second housing  120 . For example, the second fixed plate  264  may be fixed to a partial area of the second plate  121  through screw coupling. In an embodiment, the second fixed plate  264 , together with the second plate  121 , may support at least a partial area of the display (e.g., the display  140  of  FIG. 1 ). 
     In an embodiment, the second fixed plate  264  may support the rear surface of the display  140  to prevent the display  140  from being sunk or recessed toward the second rotary member  230  and the second guide member  250 . For example, the second fixed plate  264  may be coupled to the second plate  121  so as to overlap at least part of the second rotary member  230  and at least part of the second guide member  250 . 
     According to the illustrated embodiment, the second fixed plate  264  may overlap at least part of the second rotary member  230  and at least part of the second guide member  250  when the second plate  121  is viewed from above. For example, the second fixed plate  264  may overlap the portions where the second guide protrusions  234  are coupled to the second guide grooves (not illustrated) and may thus prevent the second guide member  250  from colliding and interfering with the display  140  when rotating about the fourth axis of rotation R 4 . 
       FIG. 23  may be a view in which the display  140  is omitted. However, in the case where the display  140  is disposed on the second plate  121 , the second fixed plate  264  may be disposed between at least part of the second guide member  250  and a partial area of the display  140  when the electronic device  100  is viewed in the axial directions. 
       FIG. 24A  is a view illustrating magnets of an electronic device and a motion of the rotary plates using the magnets according to an embodiment of the disclosure. 
       FIG. 24B  is a view illustrating magnets of an electronic device and a motion of rotary plates using the magnets according to an embodiment of the disclosure. 
     Referring to  FIGS. 24A and 24B , the electronic device  100  according to an embodiment may include the first housing  110 , the second housing  120 , and magnets  192  and  193  disposed on the first housing  110  and the second housing  120 , respectively. 
     In an embodiment, the magnets  192  and  193  may include the first magnet  192  disposed on the first housing  110  and the second magnet  193  disposed on the second housing  120 . For example, the first magnet  192  may be disposed on the first plate  111  of the first housing  110 . For example, the second magnet  193  may be disposed on the second plate  121  of the second housing  120 . 
     In an embodiment, the magnets  192  and  193  may provide magnetic forces for a rotary motion of the rotary plates  261  and  262 . For example, the rotary plates  261  and  262  may contain a magnetic material such that the magnetic forces of the magnets  192  and  193  act. For example, attractive forces may act between the magnets  192  and  193  and the rotary plates  261  and  262 . For example, the rotary plates  261  and  262  may at least partially contain a metallic material. In various embodiments, the entire rotary plates  261  and  262  may be formed of a metallic material, or only portions of the rotary plates  261  and  262  adjacent to the magnets  192  and  193  may be formed of a metallic material. 
     In an embodiment, when the electronic device  100  is folded, the rotary plate  261  or  262  may be attracted in one direction by the magnet  192  or  193  to perform a rotary motion. As described above, the rotary plates  261  and  262  may be rotated by the repulsive force of the display (e.g., the repulsive force RF of the display  140  of  FIG. 7 ) generated in a folding motion. According to an embodiment, when the repulsive force RF of the display  140  is relatively weak, the rotary plates  261  and  262  may be rotated by the attractive forces provided by the magnets  192  and  193 . 
     In an embodiment, the magnetic force generated by the first magnet  192  may act on the first rotary plate  261 . For example, in a folding motion of the electronic device  100 , an attractive force may act between the first rotary plate  261  and the first magnet  192 . The attractive force, together with the repulsive force RF of the display  140 , may act on part of the first rotary plate  261  to rotate the first rotary plate  261 . 
     In an embodiment, the magnetic force generated by the second magnet  193  may act on the second rotary plate  262 . For example, in a folding motion of the electronic device  100 , an attractive force may act between the second rotary plate  262  and the second magnet  193 . The attractive force, together with the repulsive force RF of the display  140 , may act on part of the second rotary plate  262  to rotate the second rotary plate  262 . 
       FIG. 24A  may be a view in which the rotary plates  261  and  262  are omitted. However, in the case where the rotary plates  261  and  262  are disposed in the housings  110  and  120 , the magnets  192  and  193  may be disposed in positions overlapping the rotary plates  261  and  262 . For example, in the case where the first rotary plate  261  is disposed on the first plate  111  in  FIG. 24A , the first magnet  192  may overlap the first rotary plate  261  when the first plate  111  is viewed from above. For example, in the case where the second rotary plate  262  is disposed on the second plate  121  in  FIG. 24A , the second magnet  193  may overlap the second rotary plate  262  when the second plate  121  is viewed from above. 
       FIG. 25  is a view illustrating reinforcing plates of an electronic device according to an embodiment of the disclosure. 
       FIG. 26A  is a view illustrating a display and reinforcing plates of an electronic device according to an embodiment of the disclosure. 
       FIG. 26B  is a view illustrating a display and reinforcing plates of an electronic device according to an embodiment of the disclosure. 
     Referring to  FIGS. 25, 26A, and 26B , the electronic device  100  according to an embodiment may include the reinforcing plates  194  and  195  supporting the rear surfaces of at least partial areas of the display  140 . For example, the reinforcing plates  194  and  195  may include the first reinforcing plate  194  disposed in the first housing  110  and the second reinforcing plate  195  disposed in the second housing  120 . 
     In an embodiment, the first reinforcing plate  194  may be disposed on a partial area of the first plate  111 . The first reinforcing plate  194  may extend in the axial directions. In an embodiment, the first reinforcing plate  194  may be disposed between the first fixed plate  263  and the first rotary plate  261 . For example, the first reinforcing plate  194  may be configured to support the display  140  together with the first fixed plate  263 , the first rotary plate  261 , and the first plate  111 . 
     In an embodiment, the first reinforcing plate  194  may include a specified pattern (e.g., a lattice pattern or a slit pattern) such that at least part thereof is able to be bent together with the display  140 . In various embodiments, the first reinforcing plate  194  may be formed of a material (e.g., a polymer, rubber, or leather) that can be bent. 
     In an embodiment, the second reinforcing plate  195  may be disposed on a partial area of the second plate  121 . The second reinforcing plate  195  may extend in the axial directions. In an embodiment, the second reinforcing plate  195  may be disposed between the second fixed plate  264  and the second rotary plate  262 . For example, the second reinforcing plate  195  may be configured to support the display  140  together with the second fixed plate  264 , the second rotary plate  262 , and the second plate  121 . 
     In an embodiment, the second reinforcing plate  195  may include a specified pattern (e.g., a lattice pattern or a slit pattern) such that at least part thereof is able to be bent together with the display  140 . In various embodiments, the second reinforcing plate  195  may be formed of a material (e.g., a polymer, rubber, or leather) that can be bent. 
     In an embodiment, the first reinforcing plate  194  and the second reinforcing plate  195  may have, in at least a partial area thereof, a plurality of openings  197  so as to include a lattice pattern and/or a slit pattern. The reinforcing plates  194  and  195  including the lattice pattern and/or the slit pattern may be bent or unbent together with the display  140 . For example, the plurality of openings  197  may extend in the axial directions. The plurality of openings  197  may be spaced apart from each other in the direction perpendicular to the axial directions. Referring to  FIG. 25 , the plurality of openings  197  may be discontinuously formed in the axial directions. In various embodiments, the plurality of openings  197  may be continuously formed in the axial directions. 
     Referring to  FIGS. 26A and 26B , the reinforcing plates  194  and  195  may be attached to the rear surfaces of partial areas of the display  140 . For example, so as to be bent or unbent together with the out-folding areas  145  and  146  of the display  140 , the reinforcing plates  194  and  195  may be attached to sections of the rear surface of the display  140  that include the out-folding areas  145  and  146 . 
     In an embodiment, the first reinforcing plate  194  may overlap the first out-folding area  145  of the display  140 . For example, when the rear surface of the display  140  is viewed, the entire first out-folding area  145  may overlap the first reinforcing plate  194 . In an embodiment, the first reinforcing plate  194  may extend from part of the first area  141  to part of the in-folding area  144  through the first out-folding area  145 . For example, when the cross-section of the display  140  is viewed, the length of the first reinforcing plate  194  may be greater than the length of the first out-folding area  145 . 
     The position and/or length of the first reinforcing plate  194  is not limited to the illustrated embodiment. In another embodiment, the first reinforcing plate  194  may be located on only the rear surface of the first out-folding area  145 . In the other embodiment, when the cross-section of the display  140  is viewed, the length of the first reinforcing plate  194  may be substantially the same as the length of the first out-folding area  145 . 
     In an embodiment, the second reinforcing plate  195  may overlap the second out-folding area  146  of the display  140 . For example, when the rear surface of the display  140  is viewed, the entire second out-folding area  146  may overlap the second reinforcing plate  195 . In an embodiment, the second reinforcing plate  195  may extend from part of the second area  142  to part of the in-folding area  144  through the second out-folding area  146 . For example, when the cross-section of the display  140  is viewed, the length of the second reinforcing plate  195  may be greater than the length of the second out-folding area  146 . 
     The position and/or length of the second reinforcing plate  195  is not limited to the illustrated embodiment. In another embodiment, the second reinforcing plate  195  may be located on only the rear surface of the second out-folding area  146 . In the other embodiment, when the cross-section of the display  140  is viewed, the length of the second reinforcing plate  195  may be substantially the same as the length of the second out-folding area  146 . 
     In various embodiments, the areas where the first reinforcing plate  194  and the second reinforcing plate  195  are disposed may substantially correspond to non-adhesive areas where the display  140  is not attached with other components of the electronic device  100 . Referring to  FIGS. 21A, 21B, and 25  together, the first reinforcing plate  194  may be disposed on the first non-adhesive area (e.g., the first non-adhesive area NAA 1  of  FIGS. 21A and 21B ), and the second reinforcing plate  195  may be disposed on the second non-adhesive area (e.g., the second non-adhesive area NAA 2  of  FIGS. 21A and 21B ). 
     An electronic device  100  according to an embodiment may include a housing including a first housing  110  and a second housing  120 , a display  140  that extends from the first housing  110  to the second housing  120 , and a hinge structure  200  that rotatably connects the first housing  110  and the second housing  120 . The hinge structure  200  may include a fixed member  210 , a first rotary member  220  coupled to the fixed member  210  so as to be rotatable about a first axis of rotation R 1  and connected with the first housing  110 , the first axis of rotation R 1  extending parallel to an axial direction, a second rotary member  230  coupled to the fixed member  210  so as to be rotatable about a second axis of rotation R 2  parallel to the axial direction and connected with the second housing  120 , a first guide member  240  coupled to the first rotary member  220  so as to be rotatable about a third axis of rotation R 3  parallel to the first axis of rotation R 1 , a second guide member  250  coupled to the second rotary member  230  so as to be rotatable about a fourth axis of rotation R 4  parallel to the second axis of rotation R 2 , a first rotary plate  261  that is at least partially coupled to the first guide member  240  to rotate about the third axis of rotation R 3  together with the first guide member  240  and that supports a partial area of the display  140 , and a second rotary plate  262  that is at least partially coupled to the second guide member  250  to rotate about the fourth axis of rotation R 4  together with the second guide member  250  and that supports another partial area of the display  140 . The hinge structure  200  may be configured such that when the first housing  110  and/or the second housing  120  is folded or unfolded, the first rotary member  220  may rotate about the first axis of rotation R 1  in a first rotational direction, the first guide member  240  and the first rotary plate  261  may rotate about the third axis of rotation R 3  in the first rotational direction, the second rotary member  230  may rotate about the second axis of rotation R 2  in a second rotational direction opposite to the first rotational direction, and the second guide member  250  and the second rotary plate  262  may rotate about the fourth axis of rotation R 4  in the second rotational direction. 
     In various embodiments, the hinge structure  200  may be configured such that the third axis of rotation R 3  and the fourth axis of rotation R 4  are located between opposite surfaces  140   a  and  140   b  of the display  140  in a thickness direction. 
     In various embodiments, the first guide member  240  may include a first guide groove  241  having an arc shape, the first rotary member  220  may include a first guide protrusion  224  accommodated in the first guide groove  241 , and the third axis of rotation R 3  may be defined as a virtual axis extending parallel to the axial direction from the center of the arc of the first guide groove  241 . The second guide member  250  may include a second guide groove  251  having an arc shape, the second rotary member  230  may include a second guide protrusion  234  accommodated in the second guide groove  251 , and the fourth axis of rotation R 4  may be defined as a virtual axis extending parallel to the axial direction from the center of the arc of the second guide groove  251 . 
     In various embodiments, the first rotary member  220  may include a first opening area  223  in which the first guide member  240  is disposed, and the first guide protrusion  234  may protrude from a sidewall of the first opening area  223  in the axial direction. The second rotary member  230  may include a second opening area  233  in which the second guide member  250  is disposed, and the second guide protrusion  234  may protrude from a sidewall  2331  or  2332  of the second opening area  233  in the axial direction. The sidewalls of the first opening area  223  and the second opening area  233  may be substantially perpendicular to the axial direction. 
     In various embodiments, the first guide member  240  may include a side surface  242  that faces the sidewall of the first opening area  223 , and the first guide groove  241  may be formed on at least part of the side surface  242  of the first guide member  240 . The second guide member  250  may include a side surface  252  or  253  that faces the sidewall  2331  or  2332  of the second opening area  233 , and the second guide groove  251  may be formed on at least part of the side surface  252  or  253  of the second guide member  250 . 
     In various embodiments, the hinge structure  200  may further include a first connecting shaft  211  that rotatably connects the first rotary member  220  to the fixed member  210  and forms the first axis of rotation R 1  and a second connecting shaft  212  that rotatably connects the second rotary member  230  to the fixed member  210  and forms the second axis of rotation R 2 . The first rotary member  220  may be rotatable about the first connecting shaft  211  relative to the fixed member  210 , and the second rotary member  230  may be rotatable about the second connecting shaft  212  relative to the fixed member  210 . 
     In various embodiments, the first rotary member  220  may include a first base portion  222  coupled to the first housing  110  and a first extension  221  that extends from the first base portion  222  toward the fixed member  210 , and the first extension  221  may be rotatably coupled to the fixed member  210  through the first connecting shaft  211 . The second rotary member  230  may include a second base portion  232  coupled to the second housing  120  and a second extension  231  that extends from the second base portion  232  toward the fixed member  210 , and the second extension  231  may be rotatably coupled to the fixed member  210  through the second connecting shaft  212 . 
     In various embodiments, the fixed member  210  may include a first coupling portion  213  to which the first rotary member  220  and the second rotary member  230  are coupled. The first coupling portion  213  may have a first through-hole  216  formed therein in which the first connecting shaft  211  is accommodated and a second through-hole  217  formed therein in which the second connecting shaft  212  is accommodated. The first through-hole  216  and the second through-hole  217  may penetrate partial areas of the first coupling portion  213  in the axial direction. 
     In various embodiments, the first rotary member  220  may include a third through-hole  226  that is formed in the first extension  221  and in which the first connecting shaft  211  is accommodated, and the third through-hole  226  may be aligned with the first through-hole  216  in the axial direction. The second rotary member  230  may include a fourth through-hole  236  that is formed in the second extension  231  and in which the second connecting shaft  212  is accommodated, and the fourth through-hole  236  may be aligned with the second through-hole  217  in the axial direction. 
     In various embodiments, when viewed in the axial direction, the first coupling portion  213  of the fixed member  210  may overlap at least part of the first extension  221  and at least part of the second extension  231 . 
     In various embodiments, the electronic device  100  may include a fully folded state in which a first edge P 1  of the first housing  110  and a second edge P 2  of the second housing  120  parallel to the axial direction among edges of the housing make contact with each other, an unfolded state in which a third edge P 3  of the first housing  110  and a fourth edge P 4  of the second housing  120  perpendicular to the axial direction among the edges of the housing form substantially the same straight line, and an intermediate state defined as a state between the unfolded state and the fully folded state. The display  140  may be configured such that at least part thereof is curved when the electronic device is changed from the unfolded state to the fully folded state. The first rotary plate  261  and the second rotary plate  262  may rotate about the third axis of rotation R 3  and the fourth axis of rotation R 4 , respectively, by a repulsive force RF generated as the at least part of the display is curved. 
     In various embodiments, the display  140  may include a first area  141  at least partially disposed in the first housing  110  and formed to be flat, a second area  142  at least partially disposed in the second housing  120  and formed to be flat, and a folding area  143  located between the first area  141  and the second area  142 . The folding area  143  may form a flat surface together with the first area  141  and the second area  142  in the unfolded state and may at least partially form a curved surface in the fully folded state or the intermediate state. Each of the first rotary plate  261  and the second rotary plate  262  may support at least part of the folding area  143  of the display  140 . 
     In various embodiments, each of the third axis of rotation R 3  and the fourth axis of rotation R 4  may pass through at least part of the folding area  143  in a direction parallel to the axial direction. 
     In various embodiments, the folding area  143  may include an in-folding area  144 , a first out-folding area  145  located between the first area  141  and the in-folding area  144 , and a second out-folding area  146  located between the second area  142  and the in-folding area  144 . In the fully folded state, part of the in-folding area  144  may be formed to be a curved surface whose center of curvature coincides with a first folding axis F 1 , part of the first out-folding area  145  may be formed to be a curved surface whose center of curvature coincides with a second folding axis F 2 , part of the second out-folding area  146  may be formed to be a curved surface whose center of curvature coincides with a third folding axis F 3 , the first folding axis Fl may be located in a direction that a first surface  140   a  of the display  140  faces, based on the display  140 , and the second folding axis F 2  and the third folding axis F 3  may be located in a direction that a second surface  140   b  of the display  140  opposite to the first surface  140   a  faces, based on the display  140 . 
     In various embodiments, the first surface  140   a  of the display  140  may be defined as a surface that forms at least part of a front surface of the electronic device  100  in the unfolded state, and the second surface  140   b  of the display  140  may be defined as a surface that faces the first housing  110 , the second housing  120 , or the hinge structure  200 . 
     In various embodiments, when viewed in the axial direction, the third axis of rotation R 3  may overlap the first out-folding area  145 , and the fourth axis of rotation R 4  may overlap the second out-folding area  146 . 
     In various embodiments, the first rotary plate  261  may include a first support portion  261   a  that extends in the axial direction, and a second support portion  26   1   b  and a third support portion  261   c  that extend from the first support portion  261   a  in a direction perpendicular to the axial direction, and a partial area of the display  140  may be attached to the first support portion  261   a.  The second support portion  261   b  and the third support portion  261   c  may be brought into contact with, or spaced apart from, the display  140  as the first rotary plate  261  rotates. The second rotary plate  262  may include a fourth support portion  262   a  that extends in the axial direction, and a fifth support portion  262   b  and a sixth support portion  262   c  that extend from the fourth support portion  262   a  in a direction perpendicular to the axial direction, and a partial area of the display  140  may be attached to the fourth support portion  262   a.  The fifth support portion  262   b  and the sixth support portion  262   c  may be brought into contact with, or spaced apart from, the display  140  as the second rotary plate  262  rotates. 
     In various embodiments, the first housing  110  may include a first plate  111  on which at least part of the display  140  is disposed, and the second housing  120  may include a second plate  121  on which at least part of the display  140  is disposed. The electronic device  100  may include a plurality of adhesive areas to which the display  140  is attached, and the plurality of adhesive areas may be spaced apart from each other in a direction perpendicular to the axial direction. When the display is viewed from above, the plurality of adhesive areas may include a first adhesive area AA 1  that overlaps the first plate  111 , a second adhesive area AA 2  that overlaps the second plate  121 , a third adhesive area AA 3  that overlaps the first support portion  261   a  of the first rotary plate  261 , and a fourth adhesive area AA 4  that overlaps the fourth support portion  262   a  of the second rotary plate  262 . 
     In various embodiments, the electronic device  100  may further include a first non-adhesive area NAA 1  defined between the first adhesive area AA 1  and the third adhesive area AA 3  and a second non-adhesive area NAA 2  defined between the second adhesive area AA 2  and the fourth adhesive area AA 4 . When the display  140  is viewed from above, the third axis of rotation R 3  may overlap the first non-adhesive area NAA 1 , and the fourth axis of rotation R 4  may overlap the second non-adhesive area NAA 2 . 
     An electronic device  100  according to an embodiment may include a housing including a first housing  110  and a second housing  120 , a display  140  that extends from the first housing  110  to the second housing  120 , and a hinge structure  200  that rotatably connects the first housing  110  and the second housing  120 . The hinge structure  200  may include a fixed member  210 , a first rotary member  220  that is coupled to the fixed member  210  so as to be rotatable about a first axis of rotation R 1  parallel to an axial direction and connected with the first housing  110  and that includes a first guide protrusion  224 , a second rotary member  230  that is coupled to the fixed member  210  so as to be rotatable about a second axis of rotation R 2  parallel to the axial direction and connected with the second housing  120  and that includes a second guide protrusion  234 , a first arm shaft  265  rotatably coupled to the fixed member  210  and parallel to the axial direction, a second arm shaft  166  rotatably coupled to the fixed member  210  and parallel to the axial direction, a first arm  270  that is coupled to the first arm shaft  265  and that rotates together with the first arm shaft  265 , the first arm  270  including a first cam  273  that surrounds the first arm shaft  265 , a second arm  280  that is coupled to the second arm shaft  266  and that rotates together with the second arm shaft  266 , the second arm  280  including a second cam  283  that surrounds the second arm shaft  266 , a cam member  292  coupled to the first arm shaft  265  and the second arm shaft  266  and linearly movable in the axial direction, the cam member  292  including a third cam  2921  engaged with the first cam  273  and a fourth cam  2992  engaged with the second cam  283 , a first elastic member  293   a  that is coupled to the first arm shaft  265  and that provides an elastic force to the cam member  292  in the axial direction, a second elastic member  293   b  that is coupled to the second arm shaft  266  and that provides an elastic force to the cam member  292  in the axial direction, a first guide member  240  that is coupled to the first rotary member  220  so as to be rotatable about a third axis of rotation R 3  parallel to the first axis of rotation R 1  and that includes a first guide groove  241  having an arc shape in which the first guide protrusion  224  is accommodated, the third axis of rotation R 3  being defined as the center of the arc of the first guide groove  241 , a second guide member  250  that is coupled to the second rotary member  230  so as to be rotatable about a fourth axis of rotation R 4  parallel to the second axis of rotation R 2  and that includes a second guide groove  251  having an arc shape in which the second guide protrusion  234  is accommodated, the fourth axis of rotation R 4  being defined as the center of the arc of the second guide groove  251 , a first rotary plate  261  that is coupled to the first guide member  240  to rotate together with the first guide member  240  and that supports a partial area of the display  140 , and a second rotary plate  262  that is coupled to the second guide member  250  to rotate together with the second guide member  250  and that supports another partial area of the display  140 . The first guide member  240  and the second guide member  250  may rotate relative to the first rotary member  220  and the second rotary member  230  as the first rotary member  220  and the second rotary member  230  rotate. When viewed in the axial direction, each of the third axis of rotation R 3  and the fourth axis of rotation R 4  may overlap at least a partial area of the display  140 . 
     The electronic device according to various embodiments may be one of various types of electronic devices. The electronic devices may include, for example, a portable communication device (e.g., a smartphone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, or a home appliance. According to an embodiment of the disclosure, 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. 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 any one of, or 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,” “coupled to,” “connected with,” or “connected to” another element (e.g., a second element), it means that the element may be coupled with the other element directly (e.g., wiredly), wirelessly, or via a third element. 
     As used in connection with various embodiments of the disclosure, the term “module” may include a unit implemented in hardware, software, or firmware, and may interchangeably be used with other terms, for example, “logic,” “logic block,” “part,” or “circuitry”. A module may be a single integral component, or a minimum unit or part thereof, adapted to perform one or more functions. For example, according to an embodiment, the module may be implemented in a form of an application-specific integrated circuit (ASIC). 
     Various embodiments as set forth herein may be implemented as software (e.g., the program  340 ) including one or more instructions that are stored in a storage medium (e.g., internal memory  336  or external memory  338 ) that is readable by a machine (e.g., the electronic device  301 ). For example, a processor (e.g., the processor  320 ) of the machine (e.g., the electronic device  301 ) may invoke at least one of the one or more instructions stored in the storage medium, and execute it, with or without using one or more other components under the control of the processor. This allows the machine to be operated to perform at least one function according to the at least one instruction invoked. The one or more instructions may include a code generated by a compiler or a code executable by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Wherein, the term “non-transitory” simply means that the storage medium is a tangible device, and does not include a signal (e.g., an electromagnetic wave), but this term does not differentiate between where data is semi-permanently stored in the storage medium and where the data is temporarily stored in the storage medium. 
     According to an embodiment, a method according to various embodiments of the disclosure may be included and provided in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or be distributed (e.g., downloaded or uploaded) online via an application store (e.g., PlayStore™), or between two user devices (e.g., smart phones) directly. If distributed online, at least part of the computer program product may be temporarily generated or at least temporarily stored in the machine-readable storage medium, such as memory of the manufacturer&#39;s server, a server of the application store, or a relay server. 
     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, and some of the multiple entities may be separately disposed in different components. According to various embodiments, one or more of the above-described components may be omitted, or one or more other components 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. 
     While the disclosure has been shown and described with reference to various 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 and their equivalents.