Patent Publication Number: US-2021191475-A1

Title: In-folding type hinge structure having flexible display panel installed therein

Description:
TECHNICAL FIELD 
     The invention relates to an in-folding type hinge structure having a flexible display panel installed therein and, more particularly, to an in-folding type hinge structure having a flexible display panel installed therein in which a plurality of rotation supports are provided in a central joint that connects two body portions and two sliding panels sliding in the respective body portions together in a mobile communication terminal in which a flexible display panel is provided in the two body portions which are foldably connected to each other, and the rotation supports are directly connected to the two body portions to support rotation of the body portions such that the body portions do not rotate over 180 degrees when the two body portions are fully unfolded, whereby damage of the flexible display panel provided on the surfaces of the two body portions can be prevented. 
     BACKGROUND ART 
     Mobile communication terminals are configured to perform various functions. Examples of the functions include a data and speech communication function, a function of capturing a still image or a moving image using a camera, a speech storing function, a function of reproducing a music file using a speaker system, and a function of displaying a still image or a moving image (a video). 
     Some mobile communication terminals have additional functions for playing games, and some mobile communication terminals are embodied as multimedia devices. Recent mobile communication terminals can also receive broadcast or multicast signals and reproduce a video or a television program. 
     Researches for supporting and improving other functions of mobile communication terminals in addition to the above-mentioned functions have been carried out. These researches include modification and improvement of structural constituents of the mobile communication terminals and addition and improvement of software or hardware. 
     In general, a display module of a mobile communication terminal displays information which is processed by the mobile communication terminal. For example, when the mobile communication terminal is in a call mode, the display module displays a user interface (UI) or a graphic user interface (GUI) associated with a call. 
     When the mobile communication terminal is in a video call mode or an image capturing mode, the display module displays a captured or/and received image, a UI, or a GUI. The display module includes a liquid crystal display, a thin-film transistor liquid crystal display, an organic light emitting diode, a flexible display, or a 3D display. 
     A flexible display (or a flexible LCD) has been regularly researched with its merit of deformability. It takes much time to use a rolled display like a paper roll as shown in science-fiction movie. 
     Therefore, transitional forms of flexible displays will be many used until the flexible displays are regularly used with sufficient development thereof, and these transitional forms will be similar to current structures of communication terminals. Accordingly, there is necessity for description of usage and protection of flexible displays when such flexible displays are used in mobile communication terminals. 
     CITATION LIST 
     Patent Literature 
     An example of a hinge structure for a mobile communication terminal having a flexible display panel installed therein is disclosed in Korean Patent Application Laid-open No. 10-2015-0096827 (Title of the Invention: HINGE STRUCTURE AND FOLDABLE DISPLAY DEVICE INCLUDING THE SAME). 
     SUMMARY OF THE INVENTION 
     Technical Problem 
     The invention provides an in-folding type hinge structure having a flexible display panel installed therein in which a plurality of rotation supports are provided in a central joint that connects two body portions and two sliding panels sliding in the respective body portions together, and the rotation supports are directly connected to the two body portions to support rotation of the body portions such that the body portions do not rotate over 180 degrees when the two body portions are fully unfolded, whereby damage of the flexible display panel provided on the surfaces of the two body portions can be prevented. 
     Solution to Problem 
     In order to achieve the above-mentioned objective, there is provided an in-folding type hinge structure having a flexible display panel installed therein. The in-folding type hinge structure includes: a panel portion in which the flexible display panel is installed, a joint portion ( 141 ) including a plurality of joints are formed in a central part thereof, and panels ( 112 ) are installed on both sides of the joint portion ( 141 ); outer cases ( 110 ) in which the panels ( 112 ) of the panel portion are accommodated; and sliders ( 121 ) that are rotatably coupled to an intermediate part between the panels ( 112 ), wherein the sliders ( 121 ) are accommodated in slider accommodation portions ( 124 ) in the outer cases and slide while the panels ( 112 ) are being folded or unfolded, and wherein a central joint ( 150 ) which is completely assembled is installed at the center of a bottom surface of the panels ( 112 ) and is rotatably coupled to the sliders ( 121 ) by a connection pin ( 143 ). 
     Rotation supports ( 52 ) and sub hinge plates ( 155 ) may be rotatably connected to a rear part of the central joint ( 150 ) and a first extension mount ( 151 ) may be installed in a front part thereof. 
     The rotation supports ( 52 ) may be connected to the first extension mount to be rotatable with the main hinge plates ( 153 ), symmetric supports ( 162 ) may be connected to front and rear surfaces of the rotation supports ( 52 ), and the rotation supports ( 52 ) and the symmetric supports ( 162 ) may include connecting intermediate portions which are gears engaging with each other and be configured to rotate simultaneously in opposite directions in rotation. 
     Rotation guide grooves ( 164 ) may be formed in a front part of the central joint ( 150 . 
     Rotation guide protrusions ( 166 ) may be formed in the main hinge plates ( 153 ) and the rotation guide protrusions ( 166 ) may be inserted into the rotation guide grooves ( 164 ) such that the rotation guide protrusions ( 166 ) move along the rotation guide grooves ( 164 ). 
     A movement trajectory of the main hinge plates ( 153 ) may be formed along the rotation guide grooves ( 164 ). 
     Rotation guide grooves ( 164 ) may be formed in a rear surface of a second extension support ( 152 ) and rotation guide protrusions ( 166 ) formed in a front part of the main hinge plates ( 153 ) are inserted into the rotation guide grooves ( 164 ) such that the rotation guide protrusions ( 166 ) move, and the rotation supports ( 52 ) connected to the sub hinge plates ( 155 ) may include connecting portions which are gears engaging with each other such that the rotation supports ( 52 ) move in the opposite directions at the time of rotation. 
     Advantageous Effects of Invention 
     According to the invention, it is possible to provide an in-folding type hinge structure having a flexible display panel installed therein in which a plurality of rotation supports are provided in a central joint that connects two body portions and two sliding panels sliding in the respective body portions together, and the rotation supports are directly connected to the two body portions to support rotation of the body portions such that the body portions do not rotate over 180 degrees when the two body portions are fully unfolded, whereby damage of the flexible display panel provided on the surfaces of the two body portions can be prevented. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of an in-folding type hinge structure having a flexible display panel installed therein according to the invention. 
         FIG. 2  is an exploded perspective view of a central joint illustrated in  FIG. 1 . 
         FIG. 3  is an exploded perspective view of a rear side of the in-folding type hinge structure having a flexible display panel installed therein according to the invention illustrated in  FIG. 1 . 
         FIG. 4  is an exploded perspective view of the central joint illustrated in  FIG. 3 . 
         FIG. 5  is a plan view and a front view of the in-folding type hinge structure having a flexible display panel installed therein according to the invention. 
         FIG. 6  is a rear view and a side view of the in-folding type hinge structure having a flexible display panel installed therein according to the invention. 
         FIG. 7  is a sectional view taken along line A-A′ in  FIG. 6  in a state in which the in-folding type hinge structure having a flexible display panel installed therein according to the invention is folded. 
         FIG. 8  is a sectional view of a joint portion taken along line A-A′ in  FIG. 6  in a state in which the in-folding type hinge structure having a flexible display panel installed therein according to the invention is being unfolded. 
         FIG. 9  is a sectional view of the joint portion taken along line A-A′ in  FIG. 6  in a state in which the in-folding type hinge structure having a flexible display panel installed therein according to the invention is fully unfolded. 
         FIG. 10  is a sectional view of a central joint and one body portion taken along line A-A′ in  FIG. 6  in a state in which the in-folding type hinge structure having a flexible display panel installed therein according to the invention is fully unfolded. 
         FIG. 11  is a partially enlarged sectional view of the central joint illustrated in  FIG. 10 . 
         FIG. 12  is a sectional view of the central joint in a state in which one body portion is being folded according to the invention. 
         FIG. 13  is a sectional view of the central joint in a state in which one body portion is fully folded according to the invention. 
         FIG. 14  is a first exploded perspective view of an in-folding type hinge structure having a flexible display panel installed therein according to another embodiment of the invention. 
         FIG. 15  is a second exploded perspective view of the in-folding type hinge structure having a flexible display panel installed therein according to another embodiment of the invention. 
         FIG. 16  is a third exploded perspective view of the in-folding type hinge structure having a flexible display panel installed therein according to another embodiment of the invention. 
         FIG. 17  is a perspective view illustrating a state in which a central joint portion of an in-folding type hinge structure according to another embodiment of the invention has been assembled. 
         FIG. 18  is a first exploded perspective view illustrating a state in which the central joint portion of the in-folding type hinge structure according to another embodiment of the invention has been disassembled. 
         FIG. 19  is a second exploded perspective view illustrating a state in which the central joint portion of the in-folding type hinge structure according to another embodiment of the invention has been disassembled. 
         FIG. 20  is a third exploded perspective view illustrating a state in which the central joint portion of the in-folding type hinge structure according to another embodiment of the invention has been disassembled. 
         FIG. 21  is an enlarged perspective view of a front part in  FIG. 20 . 
         FIG. 22  is a perspective view illustrating a state in which main hinge plates and sub hinge plates coupled to a central joint of the in-folding type hinge structure according to another embodiment of the invention are fully unfolded. 
         FIG. 23  is a perspective view illustrating a state in which the main hinge plates and the sub hinge plates coupled to the central joint of the in-folding type hinge structure according to another embodiment of the invention start folding in a state in which they are fully unfolded. 
         FIG. 24  is a perspective view illustrating a state in which the main hinge plates and the sub hinge plates coupled to the central joint of the in-folding type hinge structure according to another embodiment of the invention are folded by about 90 degrees. 
         FIG. 25  is a perspective view illustrating a state in which the main hinge plates and the sub hinge plates coupled to a central joint of the in-folding type hinge structure according to another embodiment of the invention are fully folded. 
         FIG. 26  is a perspective view illustrating shapes of rotation guide grooves which are formed in a front surface of the central joint of the in-folding type hinge structure according to another embodiment of the invention. 
         FIG. 27  is a front view illustrating a state in which rotation guide protrusions of the main hinge plates are inserted into the rotation guide grooves formed in the front surface of the central joint in the state in which the main hinge plates is fully folded at the central joint in the in-folding type hinge structure according to another embodiment of the invention. 
         FIG. 28  is a front view illustrating a state in which the rotation guide protrusions of the main hinge plates move in the rotation guide grooves formed in the front surface of the central joint while the main hinge plates are being unfolded in the in-folding type hinge structure according to another embodiment of the invention. 
         FIG. 29  is a front view illustrating a state in which rotation supports connected to the central joint support the main hinge plates in the state in which the main hinge plates are fully folded at the central joint in the in-folding type hinge structure according to another embodiment of the invention. 
         FIG. 30  is a front view illustrating a state in which the rotation supports connected to the central joint move while the main hinge plates are being unfolded in the in-folding type hinge structure according to another embodiment of the invention. 
         FIG. 31  is a front view illustrating a state in which reinforcement supports connected to the central joint supports the main hinge plates such that the main hinge plates are symmetric in angle in the state in which the main hinge plates are fully folded at the central joint in the in-folding type hinge structure according to another embodiment of the invention. 
         FIG. 32  is a front view illustrating a state in which the reinforcement supports connected to the central joint supports the main hinge plates such that the main hinge plates are symmetric in angle while the main hinge plates are being unfolded in the in-folding type hinge structure according to another embodiment of the invention. 
         FIG. 33  is a perspective view illustrating a state in which a flexible display panel is installed on a top surface of the in-folding type hinge structure having the flexible display panel installed therein according to another embodiment of the invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 1  is an exploded perspective view of an in-folding type hinge structure having a flexible display panel installed therein according to the invention.  FIG. 2  is an exploded perspective view of a central joint illustrated in  FIG. 1 . 
     Referring to  FIGS. 1 and 2 , in an in-folding type hinge structure having a flexible display panel installed therein according to the invention, two body portions  10  and  12  opposing each other are provided, and a central joint  50  is provided between the body portions  10  and  12  and is rotatably connected to the two body portions  10  and  12 . 
     Sliding panels  20  are provided in the two body portions  10  and  12  in the invention such that the sliding panels  20  can slide in the respective body portions  10  and  12 . 
     A joint portion  40  in which a plurality of joints are connected to each other is provided on each of the opposing surfaces of the sliding panels  20 , and the joint portions  40  are rotatably connected to the central joint  50 . 
     Two rotation supports  52  are rotatably provided on each side of the central joint  50 , and a guide groove  53  into which a rivet  54  is inserted and moves is formed in each rotation support  52 . 
     The rotation supports  52  are rotatably coupled to the central joint  50 . 
     A gap providing portion  56  that forms a gap between the two body portions  10  and  12  when the body portions  10  and  12  are fully folded is formed at both ends of the central joint  50 . 
     A flexible display panel  70  according to the invention is attached to the surfaces of the two body portions  10  and  12  in a state in which the body portions  10  and  12  and the sliding panels  20  are all coupled to the central joint  50 . 
       FIG. 3  is an exploded perspective view of a rear side of the in-folding type hinge structure having a flexible display panel installed therein according to the invention illustrated in  FIG. 1 .  FIG. 4  is an exploded perspective view of the central joint illustrated in  FIG. 3 . 
     Referring to  FIGS. 3 and 4 , a guide protrusion  22  is formed on two opposing side surfaces of each sliding panel  20  according to the invention, and a guide groove  19  into which the corresponding guide protrusion  22  is inserted and moves is formed on the inner side surfaces of the two body portions  10  and  12 . 
     A rounded contact surface  15  is formed on the opposing surfaces of the two body portions  10  and  12 , and a rivet fixing portion  17  to which a rivet  54  inserted into the guide groove  53  of the rotation supports  52  is fixed is formed in the middle of the rounded contact surface  15 . 
     Both ends of each joint portion  40  are rotatably coupled to both ends of the central joint  50 . This coupling is indicated by an arrow. The other end of the joint portion  40  which is not indicated by an arrow is also rotatably coupled to the other end of the central joint  50 . 
     The central joint  50  is rotatably coupled to the two body portions  10  and  12  and is also rotatably coupled to fronts of the joint portions  40  of the two sliding panels  20 . 
     A stopping area having a slightly recessed shape in which ends of the rotation supports  52  according to the invention are received can be formed close to the contact surfaces  15  of the body portions  10  and  12 . The stopping area may be required or may not be required depending on the shapes of the rotation supports  52  and the contact surfaces  15 . 
       FIG. 5  is a plan view and a front view of the in-folding type hinge structure having a flexible display panel installed therein according to the invention. 
     Referring to  FIG. 5 , when the flexible display panel  70  is installed in the in-folding type hinge structure having a flexible display panel installed therein according to the invention, a width of a bezel  74  can be reduced. 
     In the in-folding type hinge structure having a flexible display panel installed therein according to the invention, since the central joint  50  and the rotation supports  52  rotatably coupled to the central joint  50  support the two body portions  10  and  12 , lateral areas of the body portions  10  and  12  do not need to be formed large and thus the width of the bezel  74  can be reduced. 
       FIG. 6  is a rear view and a side view of the in-folding type hinge structure having a flexible display panel installed therein according to the invention. 
     Referring to  FIG. 6 , the central joint  50  according to the invention is rotatably coupled to joints of the joint portion  40  that is connected to the two sliding panels  20 . 
     The guide protrusions  22  of the sliding panels  20  according to the invention are inserted into the guide grooves  19  in the body portions  10  and  12  so as to move therein. 
       FIG. 7  is a sectional view taken along line A-A′ in  FIG. 6  in a state in which the in-folding type hinge structure having a flexible display panel installed therein according to the invention is folded. 
     Referring to  FIG. 7 , in the state in which the two body portions  10  and  12  are fully folded, a gap with a predetermined length is formed in a folded part of the flexible display panel  70  due to the gap providing portion  56  formed in the central joint  50 . 
       FIG. 8  is a sectional view of a joint portion taken along line A-A′ in  FIG. 6  in a state in which the in-folding type hinge structure having a flexible display panel installed therein according to the invention is being unfolded. 
     Referring to  FIG. 8 , the central joint  50  is rotatably connected to the joint portions  40 , and the rotation supports  52  of the central joint  50  are rotated and supported along the guide grooves  53  of the rotation supports  52  by the rivet fixing portions  17  of the body portions  10  and  12  and the rivets  54 . 
     In the state in which the two body portions  10  and  12  are fully folded, the surfaces of the two body portions  10  and  12  are not in close contact with each other but forms a gap with a predetermined length due to the gap providing portion  56  according to the invention. 
       FIG. 9  is a sectional view of the joint portion taken along line A-A′ in  FIG. 6  in a state in which the in-folding type hinge structure having a flexible display panel installed therein according to the invention is fully unfolded. 
     Referring to  FIG. 9 , the rotation supports  52  of the central joint  50  rotate in contact with the rounded contact surfaces  15  and the two body portions  10  and  12  are unfolded. 
     In the state in which the two body portions  10  and  12  are fully unfolded, the rotation supports  52  are in contact with the inner surfaces of the body portions  10  and  12  such that the body portions  10  and  12  is strongly prevented from rotating over 180 degrees, whereby it is possible to prevent damage of the flexible display panel  70 . 
       FIG. 10  is a sectional view of a central joint and one body portion taken along line A-A′ in  FIG. 6  in a state in which the in-folding type hinge structure having a flexible display panel installed therein according to the invention is fully unfolded.  FIG. 11  is a partially enlarged sectional view of the central joint illustrated in  FIG. 10 . 
     Referring to  FIGS. 10 and 11 , the central joint  50  and the rotation supports  52  according to the invention prevent the two body portions  10  and  12  from rotating out of a predetermined range. 
       FIG. 12  is a sectional view of the central joint in a state in which one body portion is being folded according to the invention.  FIG. 13  is a sectional view of the central joint in a state in which one body portion is fully folded according to the invention. 
     Referring to  FIGS. 12 and 13 , while the two body portions  10  and  12  are rotating about the central joint  50 , the rivet fixing portions  17  having the rivets  54  coupled thereto and the body portions  10  and  12  rotate along the guide grooves  53  of the rotation supports  52 . 
       FIG. 14  is a first exploded perspective view of an in-folding type hinge structure having a flexible display panel installed therein according to another embodiment of the invention.  FIG. 15  is a second exploded perspective view of the in-folding type hinge structure having a flexible display panel installed therein according to another embodiment of the invention.  FIG. 16  is a third exploded perspective view of the in-folding type hinge structure having a flexible display panel installed therein according to another embodiment of the invention. 
     Referring to  FIGS. 14 to 16 , an in-folding type hinge structure having a flexible display panel installed therein according to another embodiment of the invention includes: a panel portion in which the flexible display panel is installed, a joint portion  141  including a plurality of joints are formed in a central part thereof, and panels  112  are installed on both sides of the joint portion  141 ; outer cases  110  in which the panels  112  of the panel portion are accommodated; and sliders  121  that are rotatably coupled to an intermediate part between the panels  112 . The sliders  121  are accommodated in slider accommodation portions  124  in the outer cases and slide while the panels  112  are being folded or unfolded. A central joint  150  which is completely assembled is installed at the center of a bottom surface of the panels  112  and is rotatably coupled to the sliders  121  by a connection pin  143 . 
       FIG. 17  is a perspective view illustrating a state in which the central joint portion of the in-folding type hinge structure according to another embodiment of the invention has been assembled.  FIG. 18  is a first exploded perspective view illustrating a state in which the central joint portion of the in-folding type hinge structure according to another embodiment of the invention has been disassembled.  FIG. 19  is a second exploded perspective view illustrating a state in which the central joint portion of the in-folding type hinge structure according to another embodiment of the invention has been disassembled.  FIG. 20  is a third exploded perspective view illustrating a state in which the central joint portion of the in-folding type hinge structure according to another embodiment of the invention has been disassembled.  FIG. 21  is an enlarged perspective view of the front part in  FIG. 20 . 
     Referring to  FIGS. 17 and 21 , rotation supports  52  and sub hinge plates  155  are rotatably connected to a rear part of the central joint  150  and a first extension mount  151  is installed in a front part thereof. The rotation supports  52  are connected to the first extension mount to be rotatable along with the main hinge plates  153 . Symmetric supports  162  are connected to front and rear surfaces of the rotation supports  52 . 
     According to the invention, the rotation supports  52  and the symmetric supports  162  include connecting intermediate portions which are gears engaging with each other and are configured to rotate simultaneously in opposite directions in rotation. 
     According to the invention, rotation guide grooves  164  are formed in a front part of the central joint  150 . Rotation guide protrusions  166  are formed in the main hinge plates  153  and the rotation guide protrusions  166  are inserted into the rotation guide grooves  164  such that the rotation guide protrusions  166  move along the rotation guide grooves  164 . A movement trajectory of the main hinge plates  153  is formed along the rotation guide grooves  164 . 
     According to the invention, rotation guide grooves  164  are also formed in a rear surface of a second extension support  152  and rotation guide protrusions  166  formed in a front part of the main hinge plates  153  are inserted into the rotation guide grooves  164  such that the rotation guide protrusions  166  move. 
     According to the invention, the rotation supports  52  connected to the sub hinge plates  155  include connecting portions which are gears engaging with each other such that the rotation supports  52  move in the opposite directions at the time of rotation. 
       FIG. 22  is a perspective view illustrating a state in which the main hinge plates and the sub hinge plates coupled to the central joint of the in-folding type hinge structure according to another embodiment of the invention are fully unfolded.  FIG. 23  is a perspective view illustrating a state in which the main hinge plates and the sub hinge plates coupled to the central joint of the in-folding type hinge structure according to another embodiment of the invention start folding in a state in which they are fully unfolded.  FIG. 24  is a perspective view illustrating a state in which the main hinge plates and the sub hinge plates coupled to the central joint of the in-folding type hinge structure according to another embodiment of the invention are folded by about 90 degrees.  FIG. 25  is a perspective view illustrating a state in which the main hinge plates and the sub hinge plates coupled to the central joint of the in-folding type hinge structure according to another embodiment of the invention are fully folded. 
     Referring to  FIGS. 22 to 25 , in the in-folding type hinge structure according to another embodiment of the invention, the central joint  150  are coupled to the main hinge plates  153  and the sub hinge plates  155 , and the main hinge plates  153  and the sub hinge plates  155  are coupled to the bottom surface of the panels  112 . When the panels perform a folding operation, the main hinge plates  153  and the sub hinge plates  155  are folded with respect to the central joint  150  in the order illustrated in  FIGS. 22 to 25 . 
       FIG. 26  is a perspective view illustrating the shapes of the rotation guide grooves which are formed in the front surface of the central joint of the in-folding type hinge structure according to another embodiment of the invention.  FIG. 27  is a front view illustrating a state in which the rotation guide protrusions of the main hinge plates are inserted into the rotation guide grooves formed in the front surface of the central joint in the state in which the main hinge plates are fully folded at the central joint in the in-folding type hinge structure according to another embodiment of the invention.  FIG. 28  is a front view illustrating a state in which the rotation guide protrusions of the main hinge plates move in the rotation guide grooves formed in the front surface of the central joint while the main hinge plates are being unfolded in the in-folding type hinge structure according to another embodiment of the invention. 
     Referring to  FIGS. 26 to 28 , according to the invention, the rotation guide protrusions  166  formed in the front part and the rear part of the main hinge plates  153  move along the rotation guide grooves  164  formed in the central joint  150  and the extension mount  152 , and the main hinge plates  153  rotate. 
       FIG. 29  is a front view illustrating a state in which the rotation supports connected to the central joint support the main hinge plates in the state in which the main hinge plates are fully folded at the central joint in the in-folding type hinge structure according to another embodiment of the invention.  FIG. 30  is a front view illustrating a state in which the rotation supports connected to the central joint move while the main hinge plates are being unfolded in the in-folding type hinge structure according to another embodiment of the invention. 
     Referring to  FIGS. 29 and 30 , the arc-shaped rotation supports  52  according to the invention rotate along semi-cylindrical contact surfaces  15  which are formed in the main hinge plates  153 . 
       FIG. 31  is a front view illustrating a state in which the symmetric supports connected to the central joint supports the main hinge plates such that the main hinge plates are symmetric in angle in the state in which the main hinge plates are fully folded at the central joint in the in-folding type hinge structure according to another embodiment of the invention.  FIG. 32  is a front view illustrating a state in which the symmetric supports connected to the central joint supports the main hinge plates such that the main hinge plates are symmetric in angle while the main hinge plates are being unfolded in the in-folding type hinge structure according to another embodiment of the invention. 
     Referring to  FIGS. 31 and 32 , a pair of symmetric supports  162  according to the invention support the panels  112  with the gears engaging with each other such that the panels  112  are folded and unfolded at the same angle when a folding or unfolding operation is performed. 
     When only the rotation supports  52  are provided, a phenomenon in which the panels coupled to the main hinge plates  153  and the sub hinge plates  155  delaminate may occur when the panels  112  are unfolded or folded. Accordingly, the symmetric supports  162  serve to match rotation angles of the panels  112  with each other such that such a phenomenon is prevented. 
       FIG. 33  is a perspective view illustrating a state in which a flexible display panel is installed on a top surface of the in-folding type hinge structure having the flexible display panel installed therein according to another embodiment of the invention. 
     Referring to  FIG. 33 , a flexible display panel  70  is attached to the top surface of the assembled panels  112  to finally complete an in-folding type smartphone. 
     INDUSTRIAL APPLICABILITY 
     While an exemplary embodiment of the invention has been described above using specific terms, such description is only for explanation and it is obvious that the embodiment can be modified in various forms without departing from the technical spirit and scope of the appended claims. Such modified embodiments should not be understood separately from the spirit and scope of the invention and should belong to the appended claims. 
     REFERENCE SIGNS LIST 
     
         
         
           
               10 ,  12 : Body portion 
               17 : Rivet fixing portion 
               19 : Guide groove 
               20 : Sliding panel 
               22 : Guide protrusion 
               40 : Polyarticular portion 
               50 : Central joint 
               52 : Rotation support 
               53 : Guide groove 
               54 : Rivet 
               56 : Gap providing portion 
               70 : Flexible display panel