Patent Publication Number: US-2023164939-A1

Title: Foldable display device

Description:
FIELD OF INVENTION 
     The present disclosure relates to a technical field of display, and particularly to a foldable display device. 
     BACKGROUND 
     Currently, foldable display devices have become a major development direction of display industry. In order to solve a problem that a surface size of a foldable display device does not match a size of a flexible screen before and after the foldable display device is folded, a support plate avoidance mechanism is usually disposed in a bending mechanism of an inwardly foldable display device. By avoiding a support plate, enough space is reserved for a folded flexible screen, and the flexible screen forms “a drop shape” in a bending area. In an outwardly foldable display device, it is necessary to make a surface of a bending mechanism contacting a flexible screen always match the flexible screen, so that the flexible screen is neither pulled nor squeezed. 
     Therefore, in the above designs, a housing is usually disposed to sliding relative to the bending mechanism, so as to accommodate an “extra” part of the flexible screen when the foldable display device is folded inside and outside. However, a change of a gap between the housing and the bending mechanism will make an edge of the flexible screen difficult to be encapsulated, so that impurities such as dust may enter the flexible screen from a side of the flexible screen, causing problems such as poor display of the flexible screen. 
     SUMMARY OF DISCLOSURE 
     The present disclosure provides a foldable display device to solve a technical problem that an edge of a flexible display panel is difficult to be encapsulated due to a change of a gap between a housing and a bending mechanism of a current foldable display device. 
     In order to solve the technical problem, the present disclosure provides a foldable display device comprising: 
     a housing comprising a first housing and a second housing; 
     a bending mechanism disposed in the housing, connected to the first housing and the second housing, and comprising:
         a bending portion;   a first support portion disposed on a side of the bending portion, corresponding to the first housing, and comprising a first support plate and a first movement mechanism, wherein the first support plate is rotatably connected to the side of the bending portion, an end of the first movement mechanism is slidably connected to the first support plate, and another end of the first movement mechanism is fixedly connected to the first housing; and   a second support portion disposed on an opposite side of the bending portion, corresponding to the second housing, and comprising a second support plate and a second movement mechanism, wherein the second support plate is rotatably connected to the opposite side of the bending portion, an end of the second movement mechanism is slidably connected to the second support plate, and another end of the second movement mechanism is fixedly connected to the second housing;       

     a flexible display panel disposed in the housing and on sides of the first housing, the second housing, and the bending mechanism, wherein when the flexible display panel is in a folded state, both the first housing and the second housing are away from or close to the bent portion; and 
     a front frame structure disposed on a side of the flexible display panel away from the housing, covering at least a part of a side surface of the flexible display panel, and comprising a first front frame portion connected to the first housing, a second front frame portion connected to the first support portion, a third front frame portion connected to the second support portion, and a fourth front frame portion connected to the second housing. 
     The present disclosure has the following beneficial effects. In the present disclosure, a foldable display device is configured to comprise a housing, a bending mechanism disposed in the housing, a flexible display panel disposed in the housing and on a side of the bending mechanism, and a front frame structure covering at least a part of a side surface of the flexible display panel. The housing comprises a first housing and a second housing. The bending mechanism comprises a bending portion, a first support portion, and a second support portion. The first support portion comprises a first support plate and a first movement mechanism. The first support plate is rotatably connected to the side of the bending portion. An end of the first movement mechanism is slidably connected to the first support plate, and another end of the first movement mechanism is fixedly connected to the first housing, thereby driving the first housing away from or close to the bending portion. The second support portion comprises a second support plate and a second movement mechanism. The second support plate is rotatably connected to the opposite side of the bending portion. An end of the second movement mechanism is slidably connected to the second support plate, and another end of the second movement mechanism is fixedly connected to the second housing, thereby driving the second housing away from or close to the bending portion. The front frame structure comprises a first front frame portion connected to the first housing, a second front frame portion connected to the first support portion, a third front frame portion connected to the second support portion, and a fourth front frame portion connected to the second housing. During bending of the folding display device, the first front frame portion moves away from or close to the bending portion along with the first housing, the second front frame portion is connected to the first support plate, the third front frame portion is connected to the second support plate, and the second front frame portion moves away from or close to the bending portion along with the second housing. Therefore, when the folding display device is folded at any angle, sides of the flexible display panel and a gap between the housing and the bending mechanism are encapsulated, thereby preventing the flexible display panel from being exposed and damaged. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Specific implementation of the present disclosure will be described in detail below in conjunction with accompanying drawings to make technical solutions and beneficial effects of the present disclosure obvious. 
         FIG.  1    is a schematic structural diagram of a foldable display device according to an embodiment of the present disclosure. 
         FIG.  2    is a schematic structural diagram of the foldable display device in an unfolded state according to an embodiment of the present disclosure. 
         FIG.  3    is an exploded view of the foldable display device according to an embodiment of the present disclosure. 
         FIG.  4    is a schematic structural diagram of a backside of a bending mechanism in the unfolded state according to an embodiment of the present disclosure. 
         FIG.  5    is a schematic diagram of the foldable display device in a first folded state according to an embodiment of the present disclosure. 
         FIG.  6    is a schematic diagram of the foldable display device in a second folded state according to an embodiment of the present disclosure. 
         FIG.  7    is a schematic structural diagram of a front frame structure according to an embodiment of the present disclosure when the foldable display device is in the unfolded state. 
         FIG.  8    is a schematic structural diagram of a first front frame portion, a fourth front frame portion, a dust plug, and a soft strip according to an embodiment of the present disclosure. 
         FIG.  9    is a schematic structural diagram of a second front frame portion and a third front frame portion according to an embodiment of the present disclosure. 
         FIG.  10    is a schematic structural diagram of a shielding mechanism according to an embodiment of the present disclosure when the foldable display device is in the unfolded state. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure provides a foldable display device. In order to make purposes, technical solutions, and effects of the present invention clearer and more definite, the present invention will be further described in detail below with reference to accompanying drawings and embodiments. It should be understood that specific embodiments described herein are only used to explain the present invention, not used to limit the present invention. 
     Please refer to  FIG.  1    to  FIG.  10   . The present disclosure provides a foldable display device. The foldable display device comprises a housing  10 , a bending mechanism  20  disposed in the housing  10 , a flexible display panel  30  disposed in the housing  10  and on a side of the bending mechanism  20 , and a front frame structure  40  covering at least a part of a side surface of the flexible display panel  30 . The housing  10  comprises a first housing  11  and a second housing  12 . The bending mechanism  20  comprises a bending portion  21 , a first support portion  22  disposed on a side of the bending portion  21  and corresponding to the first housing  11 , and a second support portion  23  disposed on an opposite side of the bending portion  21  and corresponding to the second housing  12 . A side of the first support portion  22  is rotatably connected to the side of the bending portion  21 , and an opposite side of the first support portion  22  is slidably connected to the first housing  11 . A side of the second support portion  23  is rotatably connected to the opposite side of the bending portion  21 , and an opposite side of the second support portion  23  is slidably connected to the second housing  12 . The front frame structure  40  comprises a first front frame portion  401  connected to the first housing  11 , a second front frame portion  402  connected to the first support portion  22 , a third front frame portion  403  connected to the second support portion  23 , and a fourth front frame portion  404  connected to the second housing  12 . When the folding display device is folded at any angle, sides of the flexible display panel  30  and a gap between the housing  10  and the bending mechanism  20  are encapsulated, thereby preventing the flexible display panel  30  from being exposed and damaged. 
     The present disclosure will be further described in detail below in combination with the accompanying drawings and the specific embodiments. 
     Please refer to  FIG.  1    to  FIG.  3   .  FIG.  1    is a schematic structural diagram of a foldable display device according to an embodiment of the present disclosure.  FIG.  2    is a schematic structural diagram of the foldable display device in an unfolded state according to an embodiment of the present disclosure.  FIG.  3    is an exploded view of the foldable display device according to an embodiment of the present disclosure. 
     The present disclosure provides a foldable display device. The foldable display device comprises a housing  10 , a bending mechanism  20  disposed in the housing  10 , a flexible display panel  30  disposed in the housing  10  and on a side of the bending mechanism  20 , and a front frame structure  40  covering at least a part of a side surface of the flexible display panel  30 . 
     The housing  10  comprises a first housing  11  and a second housing  12  disposed opposite to each other. The bending mechanism  20  is housed in the housing  10  and connected to the first housing  11  and the second housing  12 . Furthermore, when the foldable display device is in an unfolded state, a surface of the bending mechanism  20  facing the flexible display panel  30  and a surface of the housing  10  facing the flexible display panel  30  are coplanar to form a support surface for the flexible display panel  30 . 
     Specifically, please refer to  FIG.  3    and  FIG.  4   .  FIG.  4    is a schematic structural diagram of a backside of a bending mechanism in the unfolded state according to an embodiment of the present disclosure. 
     In this embodiment, the bending mechanism  20  comprises a bending portion  21 , a first support portion  22 , and a second support portion  23 . The first support portion  22  comprises a first support plate  221  and a first movement mechanism  222 . The first support plate  221  is rotatably connected to the side of the bending portion  21 . An end of the first movement mechanism  222  is slidably connected to the first support plate  221 , and another end of the first movement mechanism  222  is fixedly connected to the first housing  11 , thereby driving the first housing  11  away from or close to the bending portion  21 . The second support portion  23  comprises a second support plate  231  and a second movement mechanism  232 . The second support plate  231  is rotatably connected to the opposite side of the bending portion  21 . An end of the second movement mechanism  232  is slidably connected to the second support plate  231 , and another end of the second movement mechanism  232  is fixedly connected to the second housing  12 , thereby driving the second housing  12  away from or close to the bending portion  21 . 
     Specifically, the first movement mechanism  222  is rotatably connected to the side of the bending portion  21  along a first axis. The second movement mechanism  232  is disposed opposite to the first movement mechanism  222  and rotatably connected to the opposite side of the bending portion  21  along a second axis. When the flexible display panel  30  is in a folded state, both the first housing  11  and the second housing  12  are away from or close to the bent portion  21 . 
     In this embodiment, the first movement mechanism  222  is rotatably connected to the side of the bending portion  21  along the first axis. The second movement mechanism  232  is rotatably connected to the opposite side of the bending portion  21  along the second axis. The first movement mechanism  222  is disposed opposite to the second movement mechanism  232 . When the flexible display panel  30  is in the folded state, both the first housing  11  and the second housing  12  are away from or close to the bent portion  21 . This is beneficial for the first support portion  22  and the second support portion  23  to form a wedge shape when the bending mechanism  20  is folded inwardly, thereby leaving a larger accommodating space for the flexible display panel  30  in the folded state. Furthermore, when the bending mechanism  20  is folded outward, the first housing  11  and the second housing  12  are both close to the bending portion  21 , so that a size of the housing  10  and a size of the flexible display panel  30  are kept matched, thereby preventing the flexible display panel  30  from being exposed and damaged. 
     Moreover, in this embodiment, the bending portion  21  comprises a fixing bracket  211 . One end of the first movement mechanism  222  is rotatably connected to the fixing bracket  211 , and another one end of the first movement mechanism  222  is connected to the first support plate  221 . One end of the second movement mechanism  232  is rotatably connected to the fixing bracket  211 , and another one end of the second movement mechanism  232  is connected to the second support plate  231 . 
     The first movement mechanism  222  comprises a first transmission mechanism  2221  and a first sliding plate  2222 . The second movement mechanism  232  comprises a second transmission mechanism  2321  and a second sliding plate  2322 . The first transmission mechanism  2221  is rotatably connected to the bending portion  21  along the first axis. The first transmission mechanism  2221  is slidably connected to the first sliding plate  2222  to drive the first sliding plate  2222  away from or close to the bending portion  21 . The first sliding plate  2222  is fixedly connected to the first housing  11 . The second transmission mechanism  2321  is rotatably connected to the bending portion  21  along the second axis. The second transmission mechanism  2321  is slidably connected to the second sliding plate  2322  to drive the second sliding plate  2322  away from or close to the bending portion  21 . The second sliding plate  2322  is fixedly connected to the second housing  12 . 
     Specifically, the first transmission mechanism  2221  comprises a first transmission member  22211 , a first sliding block  22212 , and a first swing rod  22213 . The second transmission mechanism  2321  comprises a second transmission member  23211 , a second sliding block  23212 , and a second swing rod  23213 . 
     One end of the first transmission member  22211  is rotatably connected to the fixing bracket  211 , and another end of the first transmission member  22211  is rotatably connected to one end of the first sliding block  22212 . Another end of the first sliding block  22212  is movably connected to the first swing rod  22213 . One end of the first swing rod  22213  is rotatably connected to the first support plate  221 , and the other end of the first swing rod  22213  is movably connected to the first sliding plate  2222 . The first sliding plate  2222  is fixedly connected to the first housing  11 . 
     One end of the second transmission member  23211  is rotatably connected to the fixing bracket  211 , and another end of the second transmission member  23211  is rotatably connected to one end of the second sliding block  23212 . Another end of the second sliding block  23212  is movably connected to the second swing rod  23213 . One end of the second swing rod  23213  is rotatably connected to the second support plate  231 , and the other end of the second swing rod  23213  is movably connected to the second sliding plate  2322 . The second sliding plate  2322  is fixedly connected to the second housing  12 . 
     The first support plate  221  is rotatably connected to the bending portion  21  along a third axis. The first sliding plate  2222  is slidably disposed on the first support plate  221 . The second support plate  231  is rotatably connected to the bending portion  21  along a fourth axis. The second sliding plate  2322  is slidably disposed on the second support plate  231 . Specifically, the first support plate  221  is provided with a first sliding groove (not shown). The second support plate  231  is provided with a second sliding groove (not shown). The first sliding block  22212  is slidably disposed in the first sliding groove. The second sliding block  23212  is slidably disposed in the second sliding groove. 
     In this embodiment, the bending mechanism  20  further comprises a first rotating mechanism  24  rotatably connected to the bending portion  21  along a fifth axis, and a second rotating mechanism  25  rotatably connected to the bending portion  21  along a sixth axis. The first rotating mechanism  24  comprises a first rotating member  241 , a second rotating member  242 , a third transmission member  243 , and a first linkage fixing member  244 . The second rotating mechanism  25  comprises a third rotating member  251 , a fourth rotating member  252 , a fourth transmission member  253 , and a second linkage fixing member  254 . It can be understood that the first axis, the third axis, and the fifth axis are parallel to each other, and the second axis, the fourth axis, and the sixth axis are parallel to each other. 
     The first rotating member  241  is rotatably connected to the bending portion  21  along the fifth axis. The third transmission member  243  is sleeved on the first rotating member  241 . The second rotating member  242  is rotatably connected to the third transmission member  243  along the third axis. The first linkage fixing member  244  is sleeved on the second rotating member  242  and fixed to the first support plate  221 . The third rotating member  251  is rotatably connected to the bending portion  21  along the sixth axis. The fourth transmission member  253  is sleeved on the third rotating member  251 . The fourth rotating member  252  is rotatably connected to the fourth transmission member  253  along the sixth axis. The second linkage fixing member  254  is sleeved on the fourth rotating member  252  and fixed to the second support plate  231 . Specifically, the third transmission member  243  is provided with a first gear portion (not shown). The fourth transmission member  253  is provided with a second gear portion (not shown). The first linkage fixing member  244  is provided with a third gear portion (not shown). The second linkage fixing member  254  is provided with a fourth gear portion (not shown). The first gear portion meshes with the second gear portion. The third gear portion meshes with the fourth gear portion. 
     The bending mechanism  20  further comprises a fixing block  26 . The first rotating member  241  and the third rotating member  251  are rotatably connected to the fixing block  26 . Each of opposite sides of the fixing block  26  is provided with a rack. The first linkage fixing member  244  is provided with a fifth gear portion (not shown). The second linkage fixing member  254  is provided with a sixth gear portion (not shown). The fifth gear portion and the sixth gear portion respectively mesh with the racks. 
     It is understandable that in this embodiment, the bending mechanism  20  may further comprise a third rotating mechanism and a fourth rotating mechanism that are disposed opposite to each other, and a fifth rotating mechanism and a sixth rotating mechanism that are disposed opposite to each other. Their structures and meshing relationships are same as those of the first rotating mechanism  24  and the second rotating mechanism  25 , which are not described in this embodiment. 
     Please refer to  FIG.  4    to  FIG.  6   .  FIG.  5    is a schematic diagram of the foldable display device in a first folded state according to an embodiment of the present disclosure.  FIG.  6    is a schematic diagram of the foldable display device in a second folded state according to an embodiment of the present disclosure. 
     In this embodiment, one of a first folded state and a second folded state is an inwardly folded state, and the other is an outwardly folded state. Furthermore, in this embodiment, the first folded state is the inwardly folded state, and the second folded state is the outwardly folded state as an example. It should be noted that when the foldable display device is in the inwardly folded state, the flexible display panel  30  is located between the first housing  11  and the second housing  12 . When the folding display device is in the outwardly folded state, the first housing  11  and the second housing  12  are both located inside the flexible display panel  30 . 
     In this embodiment, the first transmission mechanism  2221  further comprises a first fixing member  22214 . The second transmission mechanism  2321  further comprises a second fixing member  23214 . The first swing rod  22213  is provided with a third sliding groove (not shown). The second swing rod  23213  is provided with a fourth sliding groove (not shown). The first fixing member  22214  passes through the third sliding groove and is fixedly connected to the first sliding block  22212 . The second fixing member  23214  passes through the fifth sliding groove and is fixedly connected to the second sliding block  23212 . It should be noted that the first fixing member  22214  and the second fixing member  23214  may be, but are not limited to, axle pins. 
     The first transmission mechanism  2221  further comprises a third fixing member (not shown). The second transmission mechanism  2321  further comprises a fourth fixing member (not shown). The first sliding plate  2222  is provided with a fifth sliding groove (not shown). The second sliding plate  2322  is provided with a sixth sliding groove (not shown). The third fixing member passes through the fifth sliding groove and is fixedly connected to the first swing rod  22213 . The fourth fixing member passes through the sixth sliding groove and is fixedly connected to the second swing rod  23213 . It should be noted that the third fixing member and the fourth fixing member may be, but are not limited to, convex structures. 
     Specifically, the first rotating member  241  and the third rotating member  251  are rotatably connected to the fixing block  26 . The opposite sides of the fixing block  26  are respectively provided with two racks. The fifth gear portion and the sixth gear portion respectively mesh with the two racks. The first gear portion meshes with the second gear portion. The third gear portion meshes with the fourth gear portion. Therefore, when the flexible display panel  30  is in a folded state, the bending mechanism  20  rotates symmetrically. The first transmission member  22211  pushes the first sliding block  22212  to slide in the first sliding groove. The second transmission member  23211  pushes the second sliding block  23212  to slide in the second sliding groove. The first sliding block  22212  pushes the first swing rod  22213  to rotate by a first angle through the first fixing member  22214 . The second sliding block  23212  pushes the second swing rod  23213  to rotate by a second angle through the second fixing member  23214 . The first angle is same as the second angle. 
     Furthermore, the first swing rod  22213  pushes the first sliding plate  2222  to slide in the first support plate  221  through the third fixing member, so as to drive the first housing  11  away from or close to the bending portion  21 . The second swing rod  23213  pushes the second sliding plate  2322  to slide in the second support plate  231  through the fourth fixing member, so as to drive the second housing  12  away from or close to the bending portion  21 . Therefore, when the flexible display panel  30  is in the folded state, the size of the housing  10  and the size of the flexible display panel  30  are kept matched, so that the flexible display panel  30  will not be greatly pulled or squeezed during bending. 
     Specifically, as shown in  FIG.  5   , when the flexible display panel is in the first folded state, the first housing and the second housing are both located away from the bending portion. As shown in  FIG.  6   , when the flexible display panel is in the second folded state, the first housing and the second housing are both located close to the bending portion. 
     Please refer to  FIG.  3    and  FIG.  7   .  FIG.  7    is a schematic structural diagram of a front frame structure according to an embodiment of the present disclosure when the foldable display device is in the unfolded state. 
     In this embodiment, the front frame structure  40  is disposed on a side of the flexible display panel  30  away from the housing  10  and covers at least a part of the side surface of the flexible display panel  30 . The front frame structure  40  comprises a first front frame portion  401  connected to the first housing  11 , a second front frame portion  402  connected to the first support portion  22 , a second front frame portion  402  connected to the second support portion  23 , and a third front frame portion  403  connected to the second housing  12 . 
     It can be understood that in this embodiment, the front frame structure  40  is configured as four independent parts, that is, the first front frame portion  401  connected to the first housing  11 , the second front frame portion  402  connected to the first support portion  22 , the third front frame portion  403  connected to the second support portion  23 , and the fourth front frame portion  404  connected to the second housing  12 . The first housing  11  is separated from the first front frame portion  401  by a fixed distance. The first support plate  221  is separated from the second front frame portion  402  by a fixed distance. The second support plate  231  is separated from the third front frame portion  403  by a fixed distance. The second housing  12  is separated from the fourth front frame portion  404  by a fixed distance. This prevents impurities from easily entering the foldable display device due to an increase in a distance between the front frame structure  40  and the flexible display panel  30  during bending of the foldable display device, thereby effectively reducing a risk of impurities entering the foldable display device. 
     Please refer to  FIG.  3   ,  FIG.  8   , and  FIG.  9   .  FIG.  8    is a schematic structural diagram of a first front frame portion, a fourth front frame portion, a dust plug, and a soft strip according to an embodiment of the present disclosure.  FIG.  9    is a schematic structural diagram of a second front frame portion and a third front frame portion according to an embodiment of the present disclosure. 
     In this embodiment, the first front frame portion  401  is provided with a first buckle  4011  on its side close to the first housing  11 . The first housing  11  is provided with a first slot  111  corresponding to the first buckle  4011 . The first buckle  4011  is fixedly connected to the first slot  111  to fixedly connect the first front frame portion  401  and the first housing  11 . It can be understood that when the foldable display device is bent from the unfolded state to the first folded state or the second folded state, the first housing  11  moves close to or away from the bending portion  21 , and the first front frame moves close to or away from the bending portion  21  along with the first housing  11  through the first buckle  4011 . 
     The fourth front frame portion  404  is provided with a second buckle  4041  on its side close to the second housing  12 . The second housing  12  is provided with a second slot  122  corresponding to the second buckle  4041 . The second buckle  4041  is fixedly connected to the second slot  122  to fixedly connect the second front frame portion  402  and the second housing  12 . It can be understood that when the foldable display device is bent from the unfolded state to the first folded state or the second folded state, the second housing  12  moves close to or away from the bending portion  21 , and the second front frame moves close to or away from the bending portion  21  along with the second housing  12  through the second buckle  4041 . 
     The second front frame portion  402  comprises a first package body  4021  and a first extension portion  4022  disposed on the first package body  4021 . The second front frame portion  402  is connected to the first support plate  221  through the first extension portion  4022 . The third front frame portion  403  comprises a second package body  4031  and a second extension portion  4032  disposed on the second package body  4031 . The third front frame portion  403  is connected to the second support plate  231  through the second extension portion  4032 . It is understandable that the first extension portion  4022  may be a pin-shaped structure or a hook-shaped structure, and the first support plate  221  is provided with a hole-like structure corresponding to the first extension portion  4022 , so as to realize a connection between the first extension portion  4022  and the first support plate  221 . The second extension portion  4032  may be a pin-shaped structure or a hook-shaped structure, and the second support plate  231  is provided with a hole-like structure corresponding to the second extension portion  4032 , so as to realize a connection between the second extension portion  4032  and the second support plate  231 . 
     Specifically, the first package body  4021  comprises a first front end  40211  and a first side end  40212 . The first front end  40211  is disposed corresponding to a light-emitting surface of the flexible display panel  30 . The first side end  40212  is disposed corresponding to the side surface of the flexible display panel  30 . The first side end  40212  comprises the first extension portion  4022 . The second package body  4031  comprises a second front end  40311  and a second side end  40312 . The second front end  40311  is disposed corresponding to the light-emitting surface of the flexible display panel  30 . The second side end  40312  is disposed corresponding to the side surface of the flexible display panel  30 . The second side end  40312  comprises the second extension portion  4032 . It is understandable that the first front end  40211  and the first side end  40212  may be integrally formed, and the second front end  40311  and the second side end  40312  may be integrally formed. 
     Furthermore, the first front end  40211  is disposed on the light-emitting surface of the flexible display panel  30 , the first side end  40212  is disposed on the side surface of the flexible display panel  30 , thereby forming a covering structure for an edge of the flexible display panel  30 . The second front end  40311  is disposed on the light-emitting surface of the flexible display panel  30 , the second side end  40312  is disposed on the side surface of the flexible display panel  30 , thereby forming another covering structure for the edge of the flexible display panel  30 . 
     It can be understood that in this embodiment, when the foldable display device is bent from the unfolded state to the first folded state or the second folded state, the distance between the front frame structure  40  and the flexible display panel  30  is always kept constant. The first front frame portion  401  is fixedly connected to the first housing  11 , which restricts the first front frame portion  401  from moving synchronously with the first housing  11 . The fourth front frame portion  404  is fixedly connected to the second housing  12 , which restricts the fourth front frame portion  404  from moving synchronously with the second housing  12 . This avoids an increase in a distance between the front frame structure  40  and the housing  10  during the bending of the foldable display device. Furthermore, the second front frame portion  402  is connected to the first support plate  221 , which restricts the second front frame portion  402  from moving synchronously with the first support plate  221 . The third front frame portion  403  is connected to the second support plate  231 , which restricts the third front frame portion  403  from moving synchronously with the second support plate  231 . This avoids the increase in the distance between the front frame structure  40  and the flexible display panel  30  during the bending. 
     Moreover, in this embodiment, the foldable display device further comprises a soft strip  60  disposed on a side of the light-emitting surface of the flexible display panel  30 . The soft strip  60  is disposed between the front frame structure  40  and the flexible display panel  30 , and opposite ends of the soft strip  60  are respectively connected to the first front frame portion  401  and the fourth front frame portion  404 . It is understandable that the soft strip  60  is made of a flexible material. During the bending of the foldable display device, the soft strip  60  is bent along with the flexible display panel  30 , thereby further preventing external impurities from entering the foldable display device. 
     Furthermore, the opposite ends of the soft strip  60  are respectively provided with a first opening  61  and a second opening  62 . An end of the first front frame portion  401  close to the second front frame portion  402  is provided with a first hook  4012 . An end of the fourth front frame portion  404  close to the third front frame portion  403  is provided with a second hook  4042 . The first hook  4012  is connected to one end of the soft strip  60  through the first opening  61 , and the second hook  4042  is connected to the other end of the soft strip  60  through the second opening  62 , so that the soft strip  60  is connected between the first front frame portion  401  and the fourth front frame portion  404 . 
     The soft strip  60  is covered by the second front frame portion  402  and the third front frame portion  403 , and is constrained by the second front frame portion  402  and the third front frame portion  403  to be located on the light-emitting surface of the flexible display panel  30 . Specifically, the second front frame portion  402  is provided with a first sliding rail  4023  on its side close to the soft strip  60 . The flexible strip  60  is at least partially disposed in the first sliding rail  4023 . The soft strip  60  is slidably connected with the second front frame portion  402 . The third front frame portion  403  is provided with a second sliding rail  4033  on its side close to the soft strip  60 . The soft strip  60  is at least partially disposed in the second sliding rail  4033 . The soft strip  60  is slidably connected with the third front frame portion  403 . 
     Moreover, the first front end  40211  is located on a side of the soft strip  60  away from the flexible display panel  30 , and the first side end  40212  is located on a side surface of the soft strip  60 , thereby forming the first sliding rail  4023  covering an edge of the soft strip  60 . The second front end  40311  is located on the side of the soft strip  60  away from the flexible display panel  30 , and the second side end  40312  is located on the side surface of the soft strip  60 , thereby forming the second sliding rail  4033  covering the edge of the soft strip  60 . The soft strip  60  slides in the first sliding rail  4023  and the second sliding rail  4033 , and the soft strip  60  is fixed between the front frame structure  40  and the flexible display panel  30 . 
     It can be understood that the first front frame portion  401 , the second front frame portion  402 , the third front frame portion  403 , and the fourth front frame portion  404  are respectively connected to the first housing  11 , the first support plate  221 , the second support plate  231 , and the second housing  12 , so as to fix the flexible display panel  30  and the soft strip  60  in the folded state on the bending mechanism  20 . 
     As shown in  FIG.  5   , when the bending mechanism  20  is in the first folded state, the first front frame portion  401 , the second front frame portion  402 , the third front frame portion  403 , the fourth front frame portion  404 , the soft strip  60  and the flexible display panel  30  are all located between the first housing  11  and the second housing  12 , the first front frame portion  401  and the second front frame portion  402  are both close to the bending portion  21 , and the soft strip  60  is in a compressed state. As shown in  FIG.  6   , when the bending mechanism  20  is in the second folded state, the first front frame portion  401  and the second front frame portion  402  are both located on a side of the flexible display panel  30  away from the first housing  11 , the third front frame portion  403  and the fourth front frame  404  are both located on a side of the flexible display panel  30  away from the second housing  12 , the soft strip  60  is located on the side of the flexible display panel  30  away from the housing  10 , the first front frame portion  401  and the second front frame portion  402  are both away from the bending portion  21 , and the soft strip  60  is in a stretched state. Accordingly, when the flexible display panel  30  is in the folded state, the flexible strip  60  is always located between the front frame structure  40  and the flexible display panel  30 . 
     In this embodiment, the foldable display device further comprises a dust plug  50  disposed on the side surface of the flexible display panel  30  and corresponding to the bending portion  21 . The dust plug  50  comprises a third sliding rail  501 . The soft strip  60  is at least partially disposed in the third sliding rail  501  and is slidably connected with the dust plug  50 . 
     specifically, the dust plug  50  comprises a body part  51  and a hook part  52 . The body part  51  is disposed corresponding to the side surface of the flexible display panel  30 . The hook part  52  is disposed on the side of the soft strip  60  away from the flexible display panel  30 . The third sliding rail  501  is provided at a junction of the body part  51  and the hook part  52 . 
     Furthermore, the foldable display device further comprises a rear cover  27  disposed corresponding to the bending portion  21 . The rear cover  27  is connected to the bending portion  21 . The rear cover  27  is located on a side of the bending mechanism  20  away from the flexible display panel  30 . The body part  51  of the dust plug  50  is connected with the rear cover  27 . 
     Specifically, the body part  51  is fixedly connected to the rear cover  27  through an opening in the rear cover  27 . The hook part  52  squeezes and fixes the soft strip  60  to the flexible display panel  30 . It is understandable that the dust plug  50  is used to further fix the soft strip  60  on the flexible display panel  30  to improve dustproof effect of the soft strip  60 . Furthermore, the dust plug  50  itself can block a part of external impurities from entering the foldable display device. 
     Please refer to  FIG.  3    and  FIG.  10   .  FIG.  10    is a schematic structural diagram of a shielding mechanism according to an embodiment of the present disclosure when the foldable display device is in the unfolded state. 
     In this embodiment, the foldable display device further comprises a shielding mechanism  70 . The shielding mechanism  70  is disposed on a side of the bending mechanism  20  away from the flexible display panel  30  and covers the flexible display panel  30 . It can be understood that the shielding mechanism  70  is configured to shield and protect the bending mechanism  20  when the foldable display device is in the folded state. 
     The shielding mechanism  70  comprises an elastic shielding member  71  covering the bending mechanism  20 , a first shielding member  72  disposed on a side of the elastic shielding member  71  and fixedly connected to the first housing  11 , and a second shielding member  73  disposed on an opposite side of the elastic shielding member  71  and fixedly connected to the second housing  12 . The elastic shielding member  71  is connected to the bending mechanism  20 . A surface of the first shielding member  72  facing the flexible display panel  30  and a surface of the second shielding member  73  facing the flexible display panel  30  are coplanar to form a support surface for the flexible display panel  30 . 
     In this embodiment, sides of the first shielding member  72  close to the first housing  11  are provided with one or more third buckles  721 . The first housing  11  is further provided with one or more third slots (not shown) corresponding to the third buckles  721 . The third buckles  721  are fixedly connected to the third slots, so that the first shielding member  72  is fixedly connected to the first housing  11 . It can be understood that when the foldable display device is bent from the unfolded state to the first folded state or the second folded state, the first housing  11  moves close to or away from the bending portion  21 , and the first shielding member  72  moves close to or away from the bending portion  21  along with the first housing  11  through the third buckles  721   
     Sides of the second shielding member  73  close to the second housing  12  are provided with one or more fourth buckles  731 . The second housing  12  is further provided with one or more fourth slots (not shown) corresponding to the fourth buckles  731 . The fourth buckles  731  are fixedly connected to the fourth slots. It can be understood that when the foldable display device is bent from the unfolded state to the first folded state or the second folded state, the second housing  12  moves close to or away from the bending portion  21 , and the second shielding member  73  moves close to or away from the bending portion  21  along with the second housing  12  through the fourth buckles  731 . 
     Optionally, the first shielding member  72  comprises a first side, a second side, a third side, and a fourth side. The first side is parallel to the second side. The third side is parallel to the fourth side. The third side is close to the elastic shielding member  71 . The third buckles  721  are disposed on the first side, the second side, and the fourth side. The first housing  11  is provided with the third slots corresponding to the third buckles  721 . The third buckles  721  are fixedly connected to the third slots. The second shielding member  73  comprises a fifth side, a sixth side, a seventh side, and an eighth side. The fifth side is parallel to the sixth side. The seventh side is parallel to the eighth side. The seventh side is close to the elastic shielding member  71 . The fourth buckles  731  are disposed on the fifth side, the sixth side, and the eighth side. The second housing  12  is provided with the fourth slots corresponding to the fourth buckles  731 . The fourth buckles  731  are fixedly connected to the fourth slots. 
     The elastic shielding member  71  comprises a first hard part  711  located at its middle part, and a second hard part  712  and a third hard part  713  that are located at its opposite sides. The first hard part  711  is fixedly connected to the bending portion  21 . The second hard part  712  is fixedly connected to the first support portion  22 . The third hard part  713  is fixedly connected to the second support portion  23 . 
     Specifically, the second hard part  712  is fixedly connected to a side of the first support plate  221  away from the bending portion  21 . The first hard part  711  is fixedly connected to an axis of the bending portion  21 . The third hard part  713  is fixedly connected to a side of the second support plate  231  away from the bending portion  21 . A first soft part  714  is disposed between the second hard part  712  and the first hard part  711 . A second soft part  715  is disposed between the first hard part  711  and the third hard part  713 . It is understandable that the second hard part  712  may be fixed on the first support plate  221  by screws, the first hard part  711  may be fixed on the bending portion  21  by screws, and the third hard part  713  may be fixed on the second support plate  231  by screws, which are not specifically limited in this embodiment. 
     Furthermore, the first shielding member  72  covers at least a part of the first soft part  714 . The second shielding member  73  covers at least a part of the second soft part  715 . The first shielding member  72  is separated from the first soft part  714  by a fixed distance. The second shielding member  73  is separated from the second soft part  715  by a fixed distance. Therefore, during the bending of the foldable display device, the first shielding member  72  and the second shielding member  73  can drive the elastic shielding member  71  to be pulled up or compressed. 
     Moreover, as shown in  FIG.  4   , when the bending mechanism  20  is in the first folded state, the shielding mechanism  70  is located on a side of the housing  10  away from the flexible display panel  30 , and the first soft part  714  and the second soft part  715  both are in a stretched state. As shown in  FIG.  5   , when the bending mechanism  20  is in the second folded state, the elastic shielding member  71  is located between the first housing  11  and the second housing  12 , and the first soft part  714  and the second soft part  715  both are in a compressed state. 
     It can be understood that in this embodiment, when the foldable display device is bent from the unfolded state to the first folded state or the second folded state, a distance between the shielding mechanism  70  and the flexible display panel  30  is always kept constant. The first shielding member  72  is fixedly connected to the first housing  11 , which restricts the first shielding member  72  from moving synchronously with the first housing  11 . The second shielding member  73  is fixedly connected to the second housing  12 , which restricts the second shielding member  73  from moving synchronously with the second housing  12 . This avoids an increase in a distance between the shielding mechanism  70  and the housing  10  during the bending of the foldable display device. Furthermore, the second hard part  712  is fixedly connected to the side of the first support plate  221  away from the bending portion  21 , which restricts the second hard part  712  from moving synchronously with the first support plate  221 . The third hard part  713  is fixedly connected to the side of the second support plate  231  away from the bending portion  21 , which restricts the third hard part  713  from moving synchronously with the second support plate  231 . This avoids an increase in a distance between the elastic shielding member  71  and the housing  10  during the bending of the foldable display device. Therefore, during the bending of the foldable display device, the shielding mechanism  70  always supports and shields the flexible display panel  30 . 
     Furthermore, in this embodiment, the foldable display device may further comprise a touch pen  80 . The touch pen  80  can be used to click and touch the flexible display panel  30 . The second housing  12  is provided with a pen slot  121 . When the touch pen  80  is not in use, the touch pen  80  may be accommodated in the pen slot  121 . When the touch pen  80  needs to be used, the touch pen  80  may be taken out of the pen slot  121 . 
     In the above, the present disclosure provides a foldable display device. The foldable display device comprises a housing, a bending mechanism disposed in the housing, a flexible display panel disposed in the housing and on a side of the bending mechanism, and a front frame structure covering at least a part of a side surface of the flexible display panel. The housing comprises a first housing and a second housing. The bending mechanism comprises a bending portion, a first support portion, and a second support portion. The first support portion comprises a first support plate and a first movement mechanism. The first support plate is rotatably connected to the side of the bending portion. An end of the first movement mechanism is slidably connected to the first support plate, and another end of the first movement mechanism is fixedly connected to the first housing, thereby driving the first housing away from or close to the bending portion. The second support portion comprises a second support plate and a second movement mechanism. The second support plate is rotatably connected to the opposite side of the bending portion. An end of the second movement mechanism is slidably connected to the second support plate, and another end of the second movement mechanism is fixedly connected to the second housing, thereby driving the second housing away from or close to the bending portion. The front frame structure comprises a first front frame portion connected to the first housing, a second front frame portion connected to the first support portion, a third front frame portion connected to the second support portion, and a fourth front frame portion connected to the second housing. When the folding display device is folded at any angle, sides of the flexible display panel and a gap between the housing and the bending mechanism are encapsulated, thereby preventing the flexible display panel from being exposed and damaged. 
     It should be understood that those skilled in the art may make equivalent replacements or changes based on the technical solutions and inventive concepts of the present application, and all such changes or replacements shall fall within the scope of the claims of the present application.