Patent Publication Number: US-11644866-B2

Title: Foldable display and portable electronic device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 109108024, filed on Mar. 11, 2020. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The disclosure relates to a foldable display and a portable electronic device. 
     2. Description of Related Art 
     With the progress of technology, a flexible display technology has gradually developed and matured and is considered to have strong development potential. Generally, the flexible display technology includes electronic paper, flexible OLEDs, and the like. In addition, the flexible display technology is widely applied to a portable electronic device according to the requirements of the portable electronic device for functions of bending, folding, stretching and the like on a display device. Meanwhile, along with the application of flexible materials in the field of electronic display, the electronic display device can not only display in a larger area when being stretched, but also be folded as needed to facilitate carrying. 
     However, corresponding to the stretching and folding of a device mechanism on the flexible display device, a flexible display panel on the flexible display device may also correspondingly vary in shape and size due to its flexible nature, e.g. due to different degrees of bending (flattening), it may be possible to increase or decrease a length relative to the device mechanism. If the electronic device is still designed according to the mechanism characteristics of an existing electronic device, inconvenience in use may be caused, the display panel may also deviate from an original position, and the situations of bulging, wrinkling or even falling off from the mechanism may be caused. Furthermore, an adaptation degree between the flexible display panel and the device mechanism needs to be further considered, so the flexible display panel in a bent or flattened state can be completely matched with and supported by the device mechanism, and damage to the flexible display panel caused by improper design of the device mechanism during operation is avoided. 
     Based on the above, there is a need in the art for improvements in mechanisms associated with the existing flexible display device to accommodate technology development trends and market demands. 
     SUMMARY OF THE DISCLOSURE 
     The disclosure provides a foldable display and an electronic device, which achieve better matching and supporting degree between a mechanism part and the foldable display. 
     A foldable display of the disclosure includes a first bracket, a second bracket, a rotating shaft connecting the first bracket and the second bracket, at least one third bracket screwed to the rotating shaft, a fourth bracket movably coupled to the second and the third brackets, a flexible display disposed on the first and the fourth brackets, and a flexible supporting member disposed on the flexible display to be bent or flattened along with the flexible display. The rotation of the rotating shaft drives the fourth bracket via the third bracket to move relative to the second bracket. The flexible supporting member is filled in a space composed of the fourth bracket, the second bracket, the first bracket, and the flexible display. 
     A foldable display of the disclosure includes a first bracket, a second bracket, a rotating shaft connecting the first bracket and the second bracket, at least one third bracket screwed to the rotating shaft, a fourth bracket movably coupled to the second and the third brackets, a flexible display disposed on the first and the fourth brackets, and a supporting member movably disposed on the second bracket and coupled to the third bracket. The first bracket and the second bracket relatively rotate by the rotating shaft to be unfolded and closed. The rotating shaft rotates to drive the third bracket to move along the rotating shaft. The rotation of the rotating shaft drives the fourth bracket and the supporting member via the third bracket to move relative to the second bracket respectively. 
     A portable electronic device of the disclosure includes a host, a first rotating shaft and a foldable display. The first rotating shaft is connected between the host and the foldable display. The foldable display rotates by the first rotating shaft relative to the host to be unfolded and closed. The first rotating shaft has a first gear. The foldable display includes a first bracket, at least one second bracket and at least one second rotating shaft. The second rotating shaft connects the first bracket and the second bracket. The first bracket and the second bracket relatively rotate by the second rotating shaft to be unfolded and closed. The second rotating shaft has a second gear engaged with the first gear. When the host and the foldable display relatively rotate by the first rotating shaft to be unfolded and closed, the first rotating shaft drives the second rotating shaft via the first gear and the second gear, so that the second bracket rotates relative to the first bracket to be unfolded and closed. 
     Based on the above, the foldable display connects the first bracket and the second bracket by the rotating shaft, and the third bracket is screwed to the rotating shaft and coupled to the fourth bracket, so that in a process that the first bracket and the second bracket rotate by the rotating shaft to be unfolded and closed, the rotation action of the rotating shaft drives the third bracket to move along the rotating shaft, and the third bracket further drives the fourth bracket to move on the second bracket. In this way, when the flexible display is disposed on the first and the fourth brackets, that is, part of the flexible display at the fourth bracket can move along with the fourth bracket, a size difference caused by conversion of the flexible display between a bent state and a flattened state can be compensated due to movement of the fourth bracket, so that the situations of wrinkling or even falling off in the conversion process of bending or flattening are avoided. 
     In addition, when the fourth bracket is driven by the third bracket to move back and forth on the second bracket, a space is left between the first bracket and the second bracket after the fourth bracket is far away from the rotating shaft, and the foldable display in the above-mentioned embodiment of the disclosure further fills and compensates for the space by the supporting member or the flexible supporting member, so that when the foldable display is converted from a folded state to the flattened state, the space caused by the fourth bracket being far away from the first bracket is overcome, and therefore the back surface of the flexible display is supported between the first and the fourth brackets by the supporting member or the flexible supporting member besides being fixed on the first and the fourth brackets, so that the possibility that the flexible display is easily damaged by pressing operation because the flexible display is not supported by a component is avoided. 
     Besides, the supporting member applied to the above-mentioned flexible display is completed by arranging a movable component on the second bracket, or disposing the flexible supporting member on the flexible display to move along with the flexible display. 
     On the other hand, according to the portable electronic device adopting the foldable display, the second rotating shaft of the foldable display is orthogonal to the first rotating shaft between the foldable display and the host, so when the foldable display is converted between the folded state and the flattened state relative to the host, the first gear on the first rotating shaft is engaged with the second gear on the second rotating shaft, and accordingly the foldable display rotates to be unfolded and closed correspondingly by itself. 
     Based on the above, the foldable display and the portable electronic device both use the fourth bracket moving away from or close to the rotating shaft (or the first bracket) so as to provide a size compensation effect for the flexible display when the flexible display is converted from being bent to being flattened, that is, the flexible display is not fixed at one place along with stretching and retracting movement of machine body components, so that the flexible display is prevented from being wrinkled or even falling off in the deformation process. In addition, the machine body components with stretching and retracting movement still further fill the space left after unfolding (flattening) by the supporting member, and the movable supporting member or the flexible supporting member can both smoothly make the device components adapt to the deformation process of the flexible display to facilitate operation, thereby providing a sufficient supporting effect for the flexible display. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of a foldable display according to one embodiment of the disclosure. 
         FIG.  2    is an exploded diagram of part of components of the foldable display in  FIG.  1   . 
         FIG.  3 A  is a schematic diagram of part of the components of the foldable display in  FIG.  1   . 
         FIG.  3 B  is a partial cross-sectional view of the foldable display in  FIG.  1   . 
         FIG.  4    is a schematic diagram of the foldable display in  FIG.  1    in another state. 
         FIG.  5 A  is a schematic diagram of a foldable display according to another embodiment of the disclosure. 
         FIG.  5 B  is a schematic diagram of part of components in  FIG.  5 A . 
         FIG.  6 A  and  FIG.  6 B  are partial cross-sectional views of a foldable display in different states according to another embodiment of the disclosure. 
         FIG.  7 A  is a schematic diagram of a portable electronic device according to one embodiment of the disclosure. 
         FIG.  7 B  is a schematic diagram of part of components of the portable electronic device in  FIG.  7 A . 
         FIG.  7 C  is a schematic diagram of the portable electronic device in  FIG.  7 A  in another state. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
       FIG.  1    is a schematic diagram of a foldable display according to one embodiment of the disclosure.  FIG.  2    is an exploded diagram of part of components of the foldable display in  FIG.  1   . Rectangular coordinates X-Y-Z are provided herein in the component description. Referring to  FIG.  1    and  FIG.  2    at the same time, in the present embodiment, the foldable display  100  includes a first bracket  110 , a second bracket  120 , a rotating shaft  150 , a third bracket  130 , a fourth bracket  140 , a flexible display  160 , and a flexible supporting member  170 , and the rotating shaft  150  connects the first bracket  110  and the second bracket  120 , so that the first bracket  110  and the second bracket  120  relatively rotate by the rotating shaft  150  to be unfolded and closed. The third bracket  130  is screwed to the rotating shaft  150 , and the rotating shaft  150  rotates to drive the third bracket  130  to move along the rotating shaft  150 . The fourth bracket  140  is movably coupled to the second bracket  120  and the third bracket  130 . Rotation of the rotating shaft  150  drives the fourth bracket  140  via the third bracket  130  to move relative to the second bracket  120 . The flexible display  160  is disposed on the first bracket  110  and the fourth bracket  140 . The flexible supporting member  170  is disposed on the flexible display  160  to be bent or flattened along with the flexible display  160 . 
       FIG.  3 A  is a schematic diagram of part of the components of the foldable display in  FIG.  1   .  FIG.  3 B  is a partial cross-sectional view of the foldable display in  FIG.  1   .  FIG.  4    is a schematic diagram of the foldable display in  FIG.  1    in another state. Referring first to  FIG.  2   ,  FIG.  3 A  and  FIG.  4   , in detail, the rotating shaft  150  has an external thread  151 , and the third bracket  130  is located in a groove  122  of the second bracket  120  and has an internal threaded hole  131  adapting to the external thread  151 , so that when the rotating shaft  150  rotates along an X axis, the third bracket  130  is driven to move in the groove  122  along the X axis. Further, the third bracket  130  has guide posts  132 , and in addition to the fourth bracket  140  being coupled to guide parts  121  of the second bracket  120  via guide parts  142  to facilitate movement on the second bracket  120  along a Y axis, the fourth bracket  140  has guide grooves  141 , so that the guide posts  132  of the third bracket  130  are movably coupled to the guide grooves  141 . 
     The guide grooves  141  are inclined relative to a movement axial direction (i.e. the X axis) of the third bracket  130  (also equivalent to being inclined relative to the rotating shaft  150 ) herein, and the guide grooves  141  are also inclined relative to a movement axial direction (i.e. the Y axis) of the fourth bracket  140  at the same time. Thus, a movement pattern in which the third bracket  130  moves along the X axis is converted into a movement pattern in which the fourth bracket  140  moves along the Y axis by the adapting and guiding relationship of the guide posts  132  and the guide grooves  141 , that is, the movement axial direction of the third bracket  130  and the movement axial direction of the fourth bracket  140  are orthogonal to each other and are converted by the guide grooves  141  and the guide posts  132 . 
     Based on the above, when the rotating shaft  150  rotates along the X axis, the fourth bracket  140  is driven to move along the second bracket  120  via the third bracket  130 , for example, the guide post  132  moves from an end E 1  of the guide groove  141  shown in  FIG.  3 A  to an end E 2  of the guide groove  141  shown in  FIG.  4   . In other words, the first bracket  110  and the second bracket  120  relatively rotating by the rotating shaft  150  to be unfolded and closed can cause linear movement of the fourth bracket  140  relative to the second bracket  120  (and along the Y axis). 
     Accordingly, referring to  FIG.  1   ,  FIG.  3 A  and  FIG.  4    at the same time,  FIG.  1    and  FIG.  3 A  show the foldable display  100  in a folded state in which the second bracket  120  and the first bracket  110  are folded together, the fourth bracket  140  is completely overlapped with the second bracket  120 , and the flexible display  160  is in a bent state. In contrast, when the first bracket  110  and the second bracket  120  relatively rotate by the rotating shaft  150  to be unfolded, the first bracket  110  is not overlapped with the second bracket  120  and flattens the flexible display  160 , and the fourth bracket  140  moves relative to the second bracket  120  and partially protrudes from the second bracket  120  as described above, so that the fourth bracket and the second bracket are not completely overlapped. On the contrary, when the foldable display  100  makes the flexible display  160  change from the flattened state to the bent state, the fourth bracket  140  is restored from the state shown in  FIG.  4    to the state shown in  FIG.  3 A . 
     The third bracket  130  and the fourth bracket  140  relatively move because there is a size difference when the flexible display  160  changes to the flattened state due to the influence of the inner diameter and the outer diameter of a bent portion in the bent state, so the fourth bracket  140  needs to move away from the rotating shaft  150  (also equivalent to moving away from the first bracket  110 ) relatively to protrude from the second bracket  120  so as to compensate for the above size difference, and the flexible display  160  is prevented from being wrinkled or even falling off from the components when being converted from the bent state to the flattened state due to a conventional fixed structure. In other words, if the flexible display  160  is disposed on the first bracket  110  and the second bracket  120 , since there is no relative displacement between the first bracket and the second bracket in the process of rotating to be unfolded and closed, the flexible display  160  will wrinkle between the first bracket  110  and the second bracket  120  when being converted from the bent state to the flattened state, and the flexible display  160  even falls off. 
     It should be noted that the coupling form of the third bracket  130  and the fourth bracket  140  is not limited thereto, and in another embodiment not shown, the third bracket may have guide grooves instead, and the fourth bracket may have guide posts instead. 
     In addition, it should be noted that the present embodiment provides the flexible supporting member  170  as a compensation structure in order to structurally adapt to a space left between the fourth bracket  140  and the first bracket  110  since the fourth bracket is far away from the rotating shaft when the flexible display  160  is in the flattened state due to the relative movement of the third bracket  130  and the fourth bracket  140  as described above. 
     Further, referring to  FIG.  3 B  and  FIG.  4    at the same time, the flexible supporting member  170  is disposed on the back surface of the flexible display  160  and moves therewith, so that the foldable display  100  is in the folded state shown in  FIG.  3 B , in which the fourth bracket  140  moves close to the rotating shaft  150 , the flexible supporting member  170  is bent along with the flexible display  160  to partially surround the rotating shaft  150 , and the flexible supporting member  170  is substantially filled in a U-shaped space SP 1  composed of the fourth bracket  140 , the second bracket  120 , the first bracket  110 , and the flexible display  160 , so a surface S 1  of the first bracket  110 , a surface S 2  of the fourth bracket  140  and a surface S 3  of the flexible supporting member  170  form a same surface, which is a U-shaped surface in this state. 
     In contrast, when the foldable display  100  is converted to an unfolded state shown in  FIG.  4   , the flexible supporting member  170  is flattened as the flexible display  160  is unfolded, and since the fourth bracket  140  relatively moves away from the rotating shaft  150  and the first bracket  110 , the flexible supporting member  170  is also pulled to a positive Y-axis direction ( FIG.  4   ) by the fourth bracket  140  along with the flexible display  160 . The position of the flexible supporting member after being pulled is right between the first bracket  110  and the fourth bracket  140 , that is, it is equivalent to filling a space SP 2  left by the fourth bracket  140  moving away from the rotating shaft  150 , and thus it can also be regarded as filling the space composed of the fourth bracket  140 , the second bracket  120 , the first bracket  110 , and the flexible display  160  at this time. The surface S 1  of the first bracket  110 , the surface S 2  of the fourth bracket  140  and the surface S 3  of the flexible supporting member  170  form a same plane, and in the state shown in  FIG.  4   , the plane is parallel to an X-Y plane. 
     In the present embodiment, the flexible supporting member  170  may be made of an elastic and flexible material such as foam, Teflon, silica gel, and rubber, or may be made of a soft magnet to be easily accommodated in the space SP 1  as the flexible display  160  is converted between the bent state and the flattened state, and also be easily filled in the space SP 2  in the flattened state to serve as a supporting structure for the flexible display  160 . In addition, the flexible supporting member  170  of the present embodiment may also be an integrated structure with the flexible display  160 , that is, the flexible supporting member  170  may be attached to the flexible display  160  through a thin film structure, or may also share a flexible substrate with the flexible display  160 , or may be fabricated together with the flexible substrate. 
       FIG.  5 A  is a schematic diagram of a foldable display according to another embodiment of the disclosure.  FIG.  5 B  is a schematic diagram of part of components in  FIG.  5 A . Referring to  FIG.  5 A  and  FIG.  5 B  at the same time, in the present embodiment, the foldable display  200  includes a first bracket  210 , a second bracket  220 , third brackets  230 A and  230 B, a fourth bracket  240 , a rotating shaft  250 , a flexible display  160  and a flexible supporting member  170 . The flexible display  160  and the flexible supporting member  170  are identical to those of the above-mentioned embodiment, and the first bracket  210  and the second bracket  220  are similar to the first bracket  110  and the second bracket  120  described above and the descriptions thereof are omitted herein. Unlike the above-mentioned embodiment, the present embodiment finishes the same action pattern as the above-mentioned embodiment by matching one pair of third brackets  230 A and  230 B with the rotating shaft  250  and the fourth bracket  240 . 
     Further, the rotating shaft  250  of the present embodiment has external threads  251 A and  251 B that are opposite to each other in the spiral direction to correspond to an internal threaded hole  231 A of the third bracket  230 A and an internal threaded hole  231 B of the third bracket  230 B respectively. Meanwhile, the fourth bracket  240  has guide grooves  241 A and  241 B having opposite inclination directions. Guide posts of the third bracket  230 A are coupled to the guide grooves  241 A, and guide posts of the third bracket  230 B are coupled to the guide grooves  241 B. Accordingly, as shown in  FIG.  5 B , when the rotating shaft  250  rotates along an X axis, the third brackets  230 A and  230 B can be driven to move relative to each other to move close to or away from each other, and are matched with the guide grooves  241 A and  241 B in different directions at the same time, so that the fourth bracket  240  can achieve the same movement pattern as the above-mentioned embodiment. It can be seen from the above-described embodiment that the number and the movement pattern of the third brackets may be appropriately adjusted according to requirements, and accordingly the inclination state of the guide grooves is correspondingly adjusted, so that the fourth bracket reaches the same movement pattern. 
       FIG.  6 A  and  FIG.  6 B  are partial cross-sectional views of a foldable display in different states according to another embodiment of the disclosure. Referring to  FIG.  6 A  and  FIG.  6 B  at the same time, it should be noted first that the present embodiment is similar to the above-mentioned embodiment shown in  FIG.  5 A  and  FIG.  5 B , one pair of third brackets  330 A and  330 B corresponds to one pair of guide grooves  341  with different inclination angles of a fourth bracket  340  (one pair of guide posts  332  is correspondingly coupled to the guide grooves  341 ), so that the kinematic relationship between a first bracket  310 , a second bracket  320 , the third brackets  330 A and  330 B and the fourth bracket  340  can be known from the above-mentioned embodiments in  FIG.  5 A ,  FIG.  5 B , and even  FIG.  1    to  FIG.  4   , and the descriptions thereof are omitted herein. 
     The difference from the above-mentioned embodiments is that the present embodiment replaces the above-mentioned flexible supporting member  170  with a supporting member  350 . The supporting member  350  is movably disposed on the second bracket  320  and coupled to the third brackets  330 A and  330 B, the part that the rotation of a rotating shaft drives the fourth bracket  340  via the third brackets  330 A and  330 B can be known from the embodiment shown in  FIG.  5 A  and  FIG.  5 B , but the difference is that the third brackets  330 A and  330 B of the present embodiment can further drive the supporting member  350  to move relative to the second bracket  320 . 
     Further, the supporting member  350  has guide grooves RL. Part of the guide grooves RL is inclined relative to a movement axial direction of the third brackets  330 A and  330 B. The third brackets  330 A and  330 B have guide posts  331  movably coupled to the guide grooves RL. In the present embodiment, the supporting member  350  has a plurality of guide grooves RL. Each of these guide grooves RL has a first section  351  and a second section  352 , and the first section  351  is parallel to the movement axial direction of the third brackets  330 A and  330 B and the second section  352  is inclined relative to the movement axial direction of the third brackets  330 A and  330 B, so that the third brackets  330 A and  330 B can drive the supporting member  350  to move relative to the second bracket  320  when the guide posts  331  move along the second sections  352 . In a folded state shown in  FIG.  6 A , the guide posts  331  are located in the first sections  351 , and in an unfolded state shown in  FIG.  6 B , the guide posts  331  have been moved to the second sections  352 . Further, a movement path of the supporting member  350  on the second bracket  320  and a movement path of the fourth bracket  340  on the second bracket  320  are different from each other but are intersected. 
     As can be seen by comparing the folded state shown in  FIG.  6 A  with the unfolded (flattened) state shown in  FIG.  6 B , during the conversion from  FIG.  6 A  to  FIG.  6 B , the rotation of the rotating shaft causes the third brackets  330 A and  330 B to move away from each other, thereby driving the fourth bracket  340  to move away from the rotating shaft, which is shown in  FIG.  5 A  and  FIG.  5 B  and omitted herein. While the third brackets  330 A and  330 B move to make the fourth bracket  340  to move away, the second guide posts  331  will thus move from the first sections  351  to the second sections  352 . Accordingly, in the process that the first bracket  310  and the second bracket  320  rotate relatively to be unfolded, the fourth bracket  340  moves away from the rotating shaft to create a space so as to expose the supporting member  350 . Next, the guide posts  331  move from the first sections  351  to the second sections  352 , so that the third brackets  330 A and  330 B drive the supporting member  350  to ascend and move to the space left when the fourth bracket  340  moves away. In contrast, when the first bracket  310  and the second bracket  320  rotate relatively to be closed (converted from  FIG.  6 B  to  FIG.  6 A ), the guide posts  331  move from the second sections  352  to the first sections  351 , so that the third brackets  330 A and  330 B drive the supporting member  350  to descend and move away from the space, and then the fourth bracket  340  can move close to the rotating shaft and cover (shield) the supporting member  350 . 
     Based on the above, in the present embodiment, the movable supporting member is used instead, is movably disposed on the second bracket  320 , and successfully achieves the effect that the third brackets  330 A and  330 B can simultaneously drive the fourth bracket  340  and the supporting member  350  by the sectional design (the first sections  351  and the second sections  352 ) with different slopes of the guide grooves RL, so that the movement paths of the fourth bracket  340  and the supporting member  350  on the second bracket  320  respectively are different from each other, are orthogonal but are intersected, and the intersection is the space left after the fourth bracket  340  moves away from the rotating shaft, and the supporting member  350  filled in the space can form a same plane with the fourth bracket  340  and the first bracket  310  so as to meet the requirement of supporting a flexible display. 
     Based on the above, the flexible supporting members and the supporting member shown in  FIG.  1    to  FIG.  6 B  are all configured to be filled in the space between the fourth bracket, the second bracket, the first bracket, and the flexible display, thereby adapting to the space left after the fourth bracket moves away and supporting the flexible display. 
       FIG.  7 A  is a schematic diagram of a portable electronic device according to one embodiment of the disclosure.  FIG.  7 B  is a schematic diagram of part of components of the portable electronic device in  FIG.  7 A .  FIG.  7 C  is a schematic diagram of the portable electronic device in  FIG.  7 A  in another state. Referring to  FIG.  7 A  to  FIG.  7 C  at the same time, in the present embodiment, the portable electronic device  400  includes a host  410 , a foldable display  430  and first rotating shafts  420 . The first rotating shafts  420  are connected between the host  410  and the foldable display  430 . The foldable display  430  rotates by the first rotating shafts  420  relative to the host  410  to be unfolded and closed, and the first rotating shafts  420  have first gear  421 . The foldable display  430  is similar to the above-mentioned foldable display  100  or  200  and includes a first bracket  431 , second brackets  432 , third brackets  433 , fourth brackets  434 , second rotating shafts  435 , and flexible displays  436 . The second rotating shafts  435  connect the first bracket  431  and the second brackets  432 . The first bracket  431  and the second brackets  432  relatively rotate by the second rotating shafts  435  to be unfolded and closed. The second rotating shaft  435  has a second gear  435   a  engaged with the first gear  421 , and the first gear  421  is orthogonal to the second gear  435   a , that is, the first gear  421  is coaxially arranged with the first rotating shaft  420  (both taking an axis L 1  as the rotating center thereof), and the second gear  435   a  is coaxially arranged with the second rotating shaft  435  (both taking an axis L 2  as the rotating center thereof). 
     Accordingly, the host  410  and the foldable display  430  can relatively rotate by the first rotating shafts  420  to be unfolded and closed, and the first rotating shafts  420  drive the second rotating shafts  435  via the first gear  421  and the second gear  435   a , so that the second brackets  432  rotate relative to the first bracket  431  to be unfolded and closed, thereby enabling the unfolding and closing of the foldable display  430  to be in a linkage relationship with the unfolding and closing of the foldable display relative to the host  410 . One pair of the second brackets  432 , one pair of the third brackets  433 , one pair of fourth brackets  434  and one pair of the second rotating shafts  435  are disposed on two opposite sides of the first bracket  431  herein, and the flexible displays  436  are disposed on the first bracket  431  and the two fourth brackets  434 , so that a pair of parts of the flexible displays  436  are folded and received in two opposite recesses  431   a  on the back side of the first bracket  431  along with the second brackets  432 , the third brackets  433  and the fourth brackets  434  in a folded state shown in  FIG.  7 A . Then the foldable display  430  rotates by the first rotating shafts  420  relative to the host  410  to be unfolded as shown in  FIG.  7 C  when a user applies force on the first bracket  431 , and the pair of fourth brackets  434  and the first bracket  431  are coplanar and the flexible displays  436  are unfolded and flattened. Of course, in another embodiment not shown, only a first bracket  431  and a second bracket  432 , a third bracket  433  and a fourth bracket  434  on one side thereof may be present, while a flexible display is disposed on the first bracket  431  and the fourth bracket  434  on one side. 
     It should be noted that the present embodiment does not detail the supporting member  350  or the flexible supporting member  170  of the above-mentioned embodiments because the foldable display  430  of the present embodiment operates in a manner that the fourth brackets  434  are allowed to move away from the second rotating shafts  435  to provide a size compensation effect for the flexible displays  436  during the conversion from the folded state to an unfolded state as the above-mentioned embodiments. Therefore, the flexible supporting members  170  shown in  FIG.  1    to  FIG.  5 B , or the supporting member  350  shown in  FIG.  6 A  and  FIG.  6 B , which can be filled in the space left after the fourth brackets  434  move away, may be actually applied based on demand, so that the flexible displays  436  are completely supported by the structural members (the first bracket  431 , the fourth brackets  434  and the supporting members). 
     Based on the above, in the above-mentioned embodiments of the disclosure, the foldable display and the portable electronic device both use the fourth bracket to moving away from or close to the rotating shaft (or the first bracket) so as to provide a size compensation effect for the flexible display when the flexible display is converted from being bent to being flattened, that is, the flexible display is not fixed at one place along with stretching and retracting movement of machine body components, so that the flexible display is prevented from being wrinkled or even falling off in the deformation process. In addition, the machine body components with stretching and retracting movement still further fill the space left after unfolding (flattening) by the supporting member, and the movable supporting member or the flexible supporting member can both smoothly make the device components adapt to the deformation process of the flexible display to facilitate operation, thereby providing a sufficient supporting effect for the flexible display. 
     In addition, the rotating shaft of the foldable display is matched with another rotating shaft corresponding to the host, that is, the two rotating shafts are engaged with each other through the gears which are orthogonal to each other, so that the foldable display has the effect of correspondingly rotating to be unfolded and closed in the process of being unfolded and closed relative to the host, a display surface with a larger range is further provided for the portable electronic device, and the display view field of the portable electronic device is developed favourably.