Patent Publication Number: US-2023141223-A1

Title: Camera lifting structure and display device

Description:
RELATED APPLICATIONS 
     This application claims priority to Taiwanese Application Serial Number 110141572 filed Nov. 8, 2021, which is herein incorporated by reference. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to camera lifting structures and display devices disposed with one of these camera lifting structures. 
     Description of Related Art 
     With the advancement of display technology, the current display devices are gradually developed to designs of borderless or narrow bezels and thinner bodies. Thus, only very limited space is left inside the display device for accommodating various components. Therefore, the components that take up more space inside the conventional display device, such as lifting cameras, have gradually failed to meet the needs of the thin display devices nowadays. Apart from being easy to interfere with internal circuit components during assembly, the conventional lifting cameras may also cause electromagnetic interference or poor heat dissipation due to the close distance to the internal circuit components. 
     As a result, how to design a new camera lifting structure to make the internal structure of the thin display device achieve a better space utilization is undoubtedly an important issue that the industry highly concerns. 
     SUMMARY 
     A technical aspect of the present disclosure is to provide a camera lifting structure, which can effectively reduce the dimension to be installed inside a display device, such that the inner space for usage of the display device can be effectively saved when the camera lifting structure is installed to the display device. 
     According to an embodiment of the present disclosure, a camera lifting structure includes a rail bracket, two fixing portions, two elastic elements, two sliding portions, two main connecting rods and a camera module. The rail bracket extends along a first direction and is configured to connect with a display device. The fixing portions are disposed on two opposite ends of the rail bracket along the first direction. The elastic elements are located between the fixing portions and extend along the first direction. Each of the elastic elements has a first end and a second end opposite to the first end. Each of the first ends connects with the corresponding fixing portion. The sliding portions are respectively connected with the corresponding second end and are configured to slide along the first direction relative to the rail bracket. Each of the main connecting rods has a third end and a fourth end opposite to the third end. Each of the third ends is pivotally connected with the corresponding sliding portion. The camera module is pivotally connected with the fourth ends and is configured to move along a second direction relative to the rail bracket. The second direction is perpendicular to the first direction. 
     In one or more embodiments of the present disclosure, the camera lifting structure further includes a guiding rod. The guiding rod is connected between the fixing portions along the first direction and penetrates through the elastic elements and the sliding portions. 
     In one or more embodiments of the present disclosure, the camera lifting structure further includes two protruding portions, a damping module and two auxiliary connecting rods. The protruding portions are respectively disposed on the corresponding main connecting rod and are located between the corresponding third end and the corresponding fourth end. The damping module includes a casing, two shafts, a cover and a plurality of protruding ridges. The casing is connected with the rail bracket and has two spaces therein. Each of the shafts includes a first shaft portion and a second shaft portion. Each of the first shaft portions and the corresponding second shaft portion extend along an axis. Each of the first shaft portions is located inside the corresponding space. The second shaft portions protrude outside the casing. The cover is connected with the casing to seal up the spaces. The protruding ridges are disposed on the first shaft portions and respectively extend along the corresponding axis. The protruding ridges are separated from each other. Each of the auxiliary connecting rods has a fifth end and a sixth end opposite to the fifth end. Each of the fifth ends is connected with the corresponding second shaft portion. Each of the auxiliary connecting rods has a slot extending between the corresponding fifth end and the corresponding sixth end. Each of the protruding portions is at least partially located inside the corresponding slot. 
     In one or more embodiments of the present disclosure, the damping module further includes two first limiting portions and two pairs of second limiting portions. The first limiting portions are respectively located on the corresponding first shaft portion. The two pairs of the second limiting portions are connected with the cover. Each pair of the second limiting portions is located inside the corresponding space. Each of the first limiting portions is limited between the corresponding pair of the second limiting portions. 
     In one or more embodiments of the present disclosure, the camera lifting structure further includes two buffering pads and a central portion. The buffering pads are located between the sliding portions and are respectively disposed on the corresponding sliding portion. The central portion is disposed on the rail bracket and is at least partially located between the buffering pads. The casing is at least partially located inside the central portion. 
     In one or more embodiments of the present disclosure, the camera lifting structure further includes a first buckling portion, a torsion spring and a second buckling portion. The first buckling portion is pivotally connected with the camera module. The torsion spring is elastically connected between the camera module and the first buckling portion. The second buckling portion is disposed on the central portion and is configured to mutually buckle with the first buckling portion. 
     In one or more embodiments of the present disclosure, the rail bracket includes a first subsidiary rail bracket and a second subsidiary rail bracket. The first subsidiary rail bracket has a first groove extending along the first direction. The second subsidiary rail bracket has a second groove extending along the first direction. The sliding portions are located between the first subsidiary rail bracket and the second subsidiary rail bracket. Each of the sliding portions includes a main body, a plurality of first rolling balls and a plurality of second rolling balls. The main body is connected with the corresponding second end. The first rolling balls are rotatably disposed on the main body and are configured to roll at the first groove. The second rolling balls are rotatably disposed on the main body and are configured to roll at the second groove. 
     In one or more embodiments of the present disclosure, a material of the main body is polyoxymethylene. 
     In one or more embodiments of the present disclosure, the camera module further includes a camera and an annular structure. The annular structure is connected with the camera along the second direction. The camera lifting structure further includes at least one cable. The cable is connected between the camera and the display device and passes through the annular structure. 
     In one or more embodiments of the present disclosure, the camera lifting structure further includes at least one washer. The washer is connected between the corresponding fixing portion and the corresponding elastic element. 
     A technical aspect of the present disclosure is to provide a display device, which can effectively reduce the dimension to of a camera lifting structure to be installed within its display housing, such that the inner space for usage of the display device can be effectively saved when the camera lifting structure is installed to the display device. 
     According to an embodiment of the present disclosure, a display device includes a display housing and a camera lifting structure. The display housing has an opening. The camera lifting structure is at least partially disposed within the display housing. The camera lifting structure includes a rail bracket, two fixing portions, two elastic elements, two sliding portions, two main connecting rods and a camera module. The rail bracket extends along a first direction. The fixing portions are disposed on two opposite ends of the rail bracket along the first direction. The elastic elements are located between the fixing portions and extending along the first direction. Each of the elastic elements has a first end and a second end opposite to the first end. Each of the first ends is connected with the corresponding fixing portion. The sliding portions are respectively connected with the corresponding second end and are configured to slide along the first direction relative to the rail bracket. Each of the main connecting rods has a third end and a fourth end opposite to the third end. Each of the third ends is pivotally connected with the corresponding sliding portion. The camera module is pivotally connected with the fourth ends and is configured to move along a second direction relative to the rail bracket to protrude outside the display housing through the opening. The second direction is perpendicular to the first direction. 
     In one or more embodiments of the present disclosure, the rail bracket connects with the display housing along the first direction. 
     In one or more embodiments of the present disclosure, the camera module is configured to move toward the rail bracket and pass through the opening until the camera module is fully accommodated within the display housing. 
     In one or more embodiments of the present disclosure, the camera lifting structure further includes two protruding portions, a damping module and two auxiliary connecting rods. The protruding portions are respectively disposed on the corresponding main connecting rod and are located between the corresponding third end and the corresponding fourth end. The damping module includes a casing, two shafts, a cover and a plurality of protruding ridges. The casing is connected with the rail bracket and has two spaces therein. Each of the shafts includes a first shaft portion and a second shaft portion. Each of the first shaft portions and the corresponding second shaft portion extend along an axis. Each of the first shaft portions is located inside the corresponding space. The second shaft portions protrude outside the casing. The cover is connected with the casing to seal up the spaces. The protruding ridges are disposed on the first shaft portions and respectively extend along the corresponding axis. The protruding ridges are separated from each other. Each of the auxiliary connecting rods has a fifth end and a sixth end opposite to the fifth end. Each of the fifth ends is connected with the corresponding second shaft portion. Each of the auxiliary connecting rods has a slot extending between the corresponding fifth end and the corresponding sixth end. Each of the protruding portions is at least partially located inside the corresponding slot. 
     In one or more embodiments of the present disclosure, the camera lifting structure further includes two first limiting portions and two pairs of second limiting portions. The first limiting portions are respectively located on the corresponding first shaft portion. The two pairs of the second limiting portions are connected with the cover. Each pair of the second limiting portions is located inside the corresponding space. Each of the first limiting portions is limited between the corresponding pair of the second limiting portions. 
     In one or more embodiments of the present disclosure, the camera lifting structure further includes two buffering pads and a central portion. The buffering pads are located between the sliding portions and are respectively disposed on the corresponding sliding portion. The central portion is disposed on the rail bracket and is at least partially located between the buffering pads. The casing is at least partially located inside the central portion. 
     In one or more embodiments of the present disclosure, the camera lifting structure further includes a first buckling portion, a torsion spring and a second buckling portion. The first buckling portion is pivotally connected with the camera module. The torsion spring is elastically connected between the camera module and the first buckling portion. The second buckling portion is disposed on the central portion and is configured to mutually buckle with the first buckling portion. 
     In one or more embodiments of the present disclosure, the rail bracket includes a first subsidiary rail bracket and a second subsidiary rail bracket. The first subsidiary rail bracket has a first groove extending along the first direction. The second subsidiary rail bracket has a second groove extending along the first direction. The sliding portions are located between the first subsidiary rail bracket and the second subsidiary rail bracket. 
     In one or more embodiments of the present disclosure, each of the sliding portions includes a main body, a plurality of first rolling balls and a plurality of second rolling balls. The main body is connected with the corresponding second end. The first rolling balls are rotatably disposed on the main body and are configured to roll at the first groove. The second rolling balls rotatably disposed on the main body and are configured to roll at the second groove. 
     In one or more embodiments of the present disclosure, the camera module further includes a camera and an annular structure. The annular structure is connected with the camera along the second direction. The display device further includes at least one cable. The cable is connected with the camera and passes through the annular structure. 
     The above-mentioned embodiments of the present disclosure have at least the following advantages: 
     (1) Since the movement of camera module towards or away from the rail bracket along the second direction to switch between the accommodated state and the operation state, corresponds to the sliding of the sliding portions along the first direction and the compression and extension of the elastic elements along the first direction, the dimension of the camera lifting structure disposed within the display housing of the display device along the second direction can be effectively reduced. As a result, when the camera lifting structure is installed within the display housing of the display device, the inner space for usage of the display device can be effectively saved. Moreover, damage of the camera lifting structure due to contact with other internal components can be avoided. 
     (2) When the main connecting rods rotate relative to the camera module and the sliding portions, the protruding portions at least partially located inside the slots of the auxiliary connecting rods are also moved inside the slots of the auxiliary connecting rods with respect to the rotation of the main connecting rods, such that the auxiliary connecting rods also rotate relative to the damping module. Since the damping module provides damping to the rotation of the auxiliary connecting rods, the rotation of the main connecting rods relative to the camera module and the sliding portions is also influenced by the damping effect. In this way, the speed at which the sliding portions slide towards each other or towards the fixing portions along the first direction and the speed at which the camera module moves towards or away from the rail bracket along the second direction are under control, and the movement of the camera module towards or away from the rail bracket along the second direction also becomes more stable. 
     (3) Since the cables pass through the annular structure and are protected by the annular structure, when the camera module moves along the second direction relative to the rail bracket, the cables connected between the camera and the display device will not entangle with or tug on other components of the display device or the camera lifting structure. Thus, damage or even fracture of the cables can be avoided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure can be more fully understood by reading the following detailed description of the embodiments, with reference made to the accompanying drawings as follows: 
         FIG.  1    is a schematic front view of a camera lifting structure according to an embodiment of the present disclosure; 
         FIG.  2    is a schematic back view of the camera lifting structure of  FIG.  1   ; 
         FIG.  3    is an exploded view of the camera lifting structure of  FIG.  1   ; 
         FIG.  4    is a front view of the camera lifting structure of  FIG.  1   , in which the camera module at least partially protrudes outside the display device; 
         FIG.  5    is a front view of the camera lifting structure of  FIG.  1   , in which the camera module is fully accommodated in the display device; 
         FIG.  6    is an enlarged schematic view of the damping module of  FIG.  4   ; 
         FIG.  7    is an exploded view of the damping module of  FIG.  6   ; 
         FIG.  8    is a cross-sectional view along the sectional line A-A of  FIG.  6   ; 
         FIG.  9    is a cross-sectional view along the sectional line B-B of  FIG.  6   ; 
         FIG.  10    is a cross-sectional view along the sectional line C-C of  FIG.  5   ; 
         FIG.  11    is an exploded view of the sliding portion of  FIG.  10   ; 
         FIG.  12    is a side view of the camera lifting structure of  FIG.  1   ; 
         FIG.  13    is a locally enlarged perspective view of area M of  FIG.  12   , in which the first buckling portion is mutually buckled with the second buckling portion; 
         FIG.  14    is a locally enlarged perspective view of area M of  FIG.  12   , in which the first buckling portion is already detached from the second buckling portion; and 
         FIG.  15    is a comparative schematic view of a display device according to an embodiment of the present disclosure and a conventional display device. 
     
    
    
     DETAILED DESCRIPTION 
     Drawings will be used below to disclose embodiments of the present disclosure. For the sake of clear illustration, many practical details will be explained together in the description below. However, it is appreciated that the practical details should not be used to limit the claimed scope. In other words, in some embodiments of the present disclosure, the practical details are not essential. Moreover, for the sake of drawing simplification, some customary structures and elements in the drawings will be schematically shown in a simplified way. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Reference is made to  FIGS.  1 - 3   .  FIG.  1    is a schematic front view of a camera lifting structure  100  according to an embodiment of the present disclosure.  FIG.  2    is a schematic back view of the camera lifting structure  100  of  FIG.  1   .  FIG.  3    is an exploded view of the camera lifting structure  100  of  FIG.  1   . In this embodiment, as shown in  FIGS.  1 - 3   , a camera lifting structure  100  includes a rail bracket  110 , two fixing portions  115 , two elastic elements  120 , two sliding portions  130 , two main connecting rods  140  and a camera module  150 . The rail bracket  110  extends along a first direction D1 and is configured to connect with a display device  200  (please see  FIGS.  4 - 5  and  15   ). The fixing portions  115  are disposed on two opposite ends of the rail bracket  110  along the first direction D1. The elastic elements  120  are located between the fixing portions  115  and extend along the first direction D1. To be specific, each of the elastic elements  120  can be a spring. However, this does not intend to limit the present disclosure. Moreover, each of the elastic elements  120  has a first end  120   a  and a second end  120   b  opposite to the first end  120   a.  The first end  120   a  of each of the elastic elements  120  is connected with the corresponding fixing portion  115 . The sliding portions  130  are respectively connected with the corresponding second end  120   b  of each of the elastic elements  120  and are configured to slide along the first direction D1 relative to the rail bracket  110  with the elasticity of the elastic elements  120 . In some embodiments, the rail bracket  110  forms the guiding rail and the sliding portions  130  are movable along the guiding rail. Each of the main connecting rods  140  has a third end  140   a  and a fourth end  140   b  opposite to the third end  140   a . The third end  140   a  of each of the main connecting rods  140  is pivotally connected with the corresponding sliding portion  130 . The camera module  150  is pivotally connected with the fourth ends  140   b  of the main connecting rods  140  and is configured to move along a second direction D2 relative to the rail bracket  110  under the action of the main connecting rods  140 . The second direction D2 is perpendicular to the first direction D1. 
     Structurally speaking, as shown in  FIG.  3   , the camera lifting structure  100  further includes a guiding rod  155 . The guiding rod  155  is connected between the fixing portions  115  along the first direction D1 and penetrates through the elastic elements  120  and the sliding portions  130 . Therefore, the sliding portions  130  slides relative to the rail bracket  110  along the guiding rod  155 . In this way, the sliding portions  130  and the elastic elements  120  will not detach from the rail bracket  110 . 
     In addition, in this embodiment, the camera lifting structure  100  further includes at least one washer  195 . As shown in  FIGS.  1  and  3   , the washer  195  is connected between the corresponding fixing portion  115  and the corresponding elastic element  120 . By modifying the size, quantity or material of the washers  195 , the elastic potential energy of the elastic elements  120  can be adjusted according to the actual situations. 
     Furthermore, in this embodiment, as shown in  FIGS.  1 - 3   , the camera module  150  further includes a camera  151  and an annular structure  152 . The camera  151  is configured to capture images. The annular structure  152  is connected with the camera  151  along the second direction D2. In addition, the camera lifting structure  100  further includes at least one cable  190 . The cable  190  passes through the annular structure  152  and is connected between the camera  151  and the display device  200  (please see  FIGS.  4 - 5  and  15   ). For example, the cable  190  is connected with a mainboard (not shown) of the display device  200 . Moreover, for example, as shown in  FIGS.  1 - 3   , the camera lifting structure  100  includes two cables  190 . In practice, the two cables  190  can be respectively an electric cable or a flexible flat cable (FFC). However, this does not intend to limit the present disclosure. 
     The cables  190  pass through the annular structure  152  and are protected by the annular structure  152 . Therefore, when the camera module  150  moves along the second direction D2 relative to the rail bracket  110 , the cables  190  connected between the camera  151  and the display device  200  will not entangle with or tug on other components of the display device  200  or the camera lifting structure  100  and damages or even fractures on the cables  190  can be avoided. Moreover, the annular structure  152  can be of a complete ring or a partial ring. However, this does not intend to limit the present disclosure. 
     In this embodiment, as shown in  FIGS.  1 - 3   , the camera lifting structure  100  further includes two buffering pads  135  and a central portion  175 . The buffering pads  135  are located between the sliding portions  130  and are respectively disposed on the corresponding sliding portion  130 . The central portion  175  is disposed on the rail bracket  110  and is at least partially located between the buffering pads  135 . Thus, when the sliding portions  130  slide towards each other relative to the rail bracket  110  and reach the central portion  175 , the buffering pads  135  disposed on the sliding portions  130  will abut against the central portion  175  and act as a buffer against the impact to the central portion  175  by the sliding portions  130 . In this way, when the movements of the sliding portions  130  are stopped by the central portion  175 , the buffering pads  135  of the sliding portions  130  abut against the central portion  175  and absorb the impact therebetween, therefore the sound of impact due to the collision of the sliding portions  130  to the central portion  175  can be effectively avoided by the buffering pads  135 . 
     Reference is made to  FIGS.  4 - 5   .  FIG.  4    is a front view of the camera lifting structure  100  of  FIG.  1   , in which the camera module  150  at least partially protrudes outside the display device  200 .  FIG.  5    is a front view of the camera lifting structure  100  of  FIG.  1   , in which the camera module  150  is fully accommodated in the display device  200 . For the sake of drawing simplification, in  FIGS.  4 - 5   , the shape of the camera module  150  is only presented in hidden lines, and the cables  190  are not shown. In this embodiment, as shown in  FIGS.  4 - 5   , the display device  200  includes the camera lifting structure  100  and a display housing  210 . The display housing  210  has an opening OP. The camera lifting structure  100  is at least partially disposed within the display housing  210  of the display device  200 . To be specific, the rail bracket  110  of the camera lifting structure  100  is connected with the display housing  210  while the rail bracket  110  extends along the first direction D1. Moreover, the camera lifting structure  100  can be switched between an operation state and an accommodated state. As shown in  FIG.  4   , the camera module  150  is in the operation state that the camera  151  of the camera module  150  at least partially protrudes outside the display housing  210  of the display device  200  through the opening OP of the display housing  210  and can operate to take images. As shown in  FIG.  5   , the camera module  150  is in the accommodated state that the camera module  150  is fully accommodated in the display device  200  when it is no longer required to take images. 
     To be specific, as shown in  FIGS.  1 - 5   , the camera lifting structure  100  further includes two protruding portions  145 , a damping module  160  and two auxiliary connecting rods  170 . The protruding portions  145  are respectively disposed on the corresponding main connecting rod  140  and are located between the corresponding third end  140   a  and the corresponding fourth end  140   b.  Each of the auxiliary connecting rods  170  has a fifth end  170   a  and a sixth end  170   b  opposite to the fifth end  170   a.  The fifth end  170   a  of each of the auxiliary connecting rods  170  is connected with the damping module  160 . The damping module  160  provides damping to the rotation of the auxiliary connecting rods  170 . It is worth to note that, each of the auxiliary connecting rods  170  has a slot SL extending between the corresponding fifth end  170   a  and the corresponding sixth end  170   b.  Each of the protruding portions  145  is at least partially located inside the corresponding slot SL. 
     When the camera lifting structure  100  is switched from the operation state (as shown in  FIG.  4   ) to the accommodated state (as shown in  FIG.  5   ), the camera module  150  is pressed by the user, such that the camera module  150  moves downwardly toward the rail bracket  110  along the second direction D2. When the camera module  150  moves towards the rail bracket  110  along the second direction D2, the main connecting rods  140  rotate relative to the camera module  150  and the sliding portions  130  as the third end  140   a  and the fourth end  140   b  of each of the main connecting rods  140  are respectively and pivotally connected with the corresponding sliding portion  130  and the camera module  150 , such that the sliding portions  130  are pushed to slide towards the fixing portions  115  along the first direction D1. In this way, the elastic elements  120  are compressed and the amount of elastic potential energy stored in the elastic elements  120  is increased until the camera lifting structure  100  is completely switched to the accommodated state. 
     Furthermore, as mentioned above, the protruding portions  145  disposed on the main connecting rods  140  are at least partially located inside the slots SL of the auxiliary connecting rods  170 . Therefore, when the main connecting rods  140  rotate relative to the camera module  150  and the sliding portions  130 , the protruding portions  145  also move along the inside of the slots SL of the auxiliary connecting rods  170  with respect to the rotation of the main connecting rods  140 , such that the auxiliary connecting rods  170  also rotate relative to the damping module  160 . Since the damping module  160  provides damping to the rotation of the auxiliary connecting rods  170 , the rotation of the main connecting rods  140  relative to the camera module  150  and the sliding portions  130  is also influenced by the damping effect. In this way, both of the speed at which the sliding portions  130  slide towards the fixing portions  115  along the first direction D1 and the speed at which the camera module  150  moves towards the rail bracket  110  along the second direction D2 are varied in a controlled manner, and the movement of the camera module  150  towards the rail bracket  110  along the second direction D2 also becomes more stable. 
     When the camera lifting structure  100  is switched from the accommodated state (as shown in  FIG.  5   ) to the operation state (as shown in  FIG.  4   ), the elastic potential energy stored in the elastic elements  120  is released, such that the elastic elements  120  extend elastically, which makes the sliding portions  130  slide towards each other relative to the rail bracket  110 . Since the third end  140   a  and the fourth end  140   b  of each of the main connecting rods  140  are respectively and pivotally connected with the corresponding sliding portion  130  and the camera module  150 , the main connecting rods  140  rotate relative to the camera module  150  and the sliding portions  130 , and the camera module  150  is pushed to move upwardly away from the rail bracket  110  along the second direction D2, until the camera lifting structure  100  is completely switched to the operation state. 
     Furthermore, as mentioned above, the protruding portions  145  disposed on the main connecting rods  140  are at least partially located inside the slots SL of the auxiliary connecting rods  170 . Therefore, when the main connecting rods  140  rotate relative to the camera module  150  and the sliding portions  130 , the protruding portions  145  are also moved along the inside of the slots SL of the auxiliary connecting rods  170  with respect to the rotation of the main connecting rods  140 , such that the auxiliary connecting rods  170  also rotate relative to the damping module  160 . Since the damping module  160  provides damping to the rotation of the auxiliary connecting rods  170 , the rotation of the main connecting rods  140  relative to the camera module  150  and the sliding portions  130  is also influenced by the damping effect. In this way, both of the speed at which the sliding portions  130  slide towards each other and the speed at which the camera module  150  moves away from the rail bracket  110  along the second direction D2 are varied in a controlled manner, and the movement of the camera module  150  away from the rail bracket  110  along the second direction D2 also becomes more stable. 
     Reference is made to  FIGS.  6 - 8   .  FIG.  6    is an enlarged schematic view of the damping module  160  of  FIG.  4   .  FIG.  7    is an exploded view of the damping module  160  of  FIG.  6   .  FIG.  8    is a cross-sectional view along the sectional line A-A of  FIG.  6   . In this embodiment, as shown in  FIGS.  6 - 8   , the damping module  160  includes a casing  161 , two shafts  162  and a plurality of protruding ridges  163 . The casing  161  is connected with the rail bracket  110  and is at least partially located inside the central portion  175 . The casing  161  has two spaces SP therein. Each of the shafts  162  includes a first shaft portion  1621  and a second shaft portion  1622 . Each of the first shaft portions  1621  and the corresponding second shaft portion  1622  extend along an axis XL. Each of the first shaft portions  1621  is located inside the corresponding space SP. The second shaft portions  1622  protrude outside the casing  161 . The fifth end  170   a  of each of the auxiliary connecting rods  170  is connected with the corresponding second shaft portion  1622 . Thus, the shafts  162  can rotate relative to the casing  161  with respect to the rotation of the auxiliary connecting rods  170 . The protruding ridges  163  are disposed on the first shaft portions  1621  and respectively extend along the corresponding axis XL. The protruding ridges  163  are separated from each other. Therefore, when the spaces SP of the casing  161  are filled up with oil or other damping fluid, the viscosity of the oil in the spaces SP causes resistance to the protruding ridges  163  during rotation, which provides damping to the rotations of the shafts  162 . In this embodiment, the damping module  160  further includes a cover  166 . The cover  166  is connected with the casing  161  to seal up the spaces SP. 
     Reference is made to  FIG.  9   .  FIG.  9    is a cross-sectional view along the sectional line B-B of  FIG.  6   . In this embodiment, as shown in  FIG.  9   , the damping module  160  further includes two first limiting portions  164  and two pairs of second limiting portions  165 . The first limiting portions  164  are respectively located on the corresponding first shaft portion  1621 . As shown in  FIG.  9   , each pair of the second limiting portions  165  is located inside the corresponding space SP, and is connected with the cover  166  as shown in  FIG.  7   . In this embodiment, each of the first limiting portions  164  is limited between the corresponding pair of the second limiting portions  165 . In other words, the rotation of the shafts  162  relative to the casing  161  is limited by being stopped by the second limiting portions  165 . 
     Reference is made to  FIGS.  10 - 11   .  FIG.  10    is a cross-sectional view along the sectional line C-C of  FIG.  5   .  FIG.  11    is an exploded view of the sliding portion  130  of  FIG.  10   . In this embodiment, as shown in  FIGS.  10 - 11   , the rail bracket  110  includes a first subsidiary rail bracket  1101  and a second subsidiary rail bracket  1102 . The first subsidiary rail bracket  1101  has a first groove G 1  extending along the first direction D1. The second subsidiary rail bracket  1102  has a second groove G 2  extending along the first direction D1. The sliding portions  130  are located between the first subsidiary rail bracket  1101  and the second subsidiary rail bracket  1102 . Each of the sliding portions  130  includes a main body  131 , a plurality of first rolling balls  132  and a plurality of second rolling balls  133 . The main body  131  is connected with the corresponding second end  120   b.  The first rolling balls  132  are rotatably disposed on the main body  131  and are configured to roll at the first groove G 1 . The second rolling balls  133  are rotatably disposed on the main body  131  and are configured to roll at the second groove G 2 . In the embodiments, as shown in exemplary  FIG.  11   , the first rolling balls  132  and the second rolling balls  133  can be disposed in the holes of the plates  134  on both sides of the main body  131 . However, this does not intend to limit the present disclosure. 
     In practical applications, a material of the main body  131  can be chosen to have a stable dimension and be resistant to wearing, such as polyoxymethylene (POM). However, this does not intend to limit the present disclosure. 
     Reference is made to  FIGS.  12 - 13   .  FIG.  12    is a side view of the camera lifting structure  100  of  FIG.  1   .  FIG.  13    is a locally enlarged perspective view of area M of  FIG.  12   , in which the first buckling portion  181  is mutually buckled with the second buckling portion  185 . In this embodiment, as shown in  FIGS.  12 - 13   , the camera lifting structure  100  further includes a first buckling portion  181 , a torsion spring  183  and a second buckling portion  185 . The first buckling portion  181  is pivotally connected with the camera module  150 . The torsion spring  183  is elastically connected between the camera module  150  and the first buckling portion  181 . The second buckling portion  185  is disposed on the central portion  175  and is configured to mutually buckle with the first buckling portion  181 . When the first buckling portion  181  is mutually buckled with the second buckling portion  185 , the camera module  150  cannot move upwardly or downwardly relative to the rail bracket  110 , and the camera lifting structure  100  is fully accommodated inside the display device  200 , such that the camera lifting structure  100  is in the accommodated state. 
     Reference is made to  FIG.  14   .  FIG.  14    is a locally enlarged perspective view of area M of  FIG.  12   , in which the first buckling portion  181  is already detached from the second buckling portion  185 . When the camera lifting structure  100  is in the accommodated state (as shown in  FIG.  5   ), the camera lifting structure  100  switches to the operation state (as shown in  FIG.  4   ) after the user presses the camera module  150  towards the rail bracket  110 . In this embodiment, as shown in  FIG.  14   , the camera module  150  is pressed towards the rail bracket  110  and part of the first buckling portion  181  abuts against the second buckling portion  185 , which makes the first buckling portion  181  elastically rotate relative to the camera module  150 , such that the first buckling portion  181  is detached from the second buckling portion  185 . At this point, the elastic potential energy stored in the elastic elements  120  is released, such that the elastic elements  120  extend elastically, which make the sliding portions  130  slide towards each other relative to the rail bracket  110 . The sliding portions  130  are then stopped by the central portion  175  and the buffering pads  135  of the sliding portions  130  abut against the central portion  175 . The movements of the sliding portions  130  make the camera  151  at least partially protrude outside the display housing  210  of the display device  200  through the opening OP of the display housing  210 . The camera lifting structure  100  completely switches to the operation state that the camera  151  can take images. 
     On the contrary, when the camera lifting structure  100  is in the operation state (as shown in  FIG.  4   ), the camera lifting structure  100  switches to the accommodated state (as shown in  FIG.  5   ) after the user presses on the camera module  150  towards the rail bracket  110  along the second direction D2 through the opening OP of the display housing  210 . The camera module  150  moves downwardly until the first buckling portion  181  is mutually buckled with the second buckling portion  185 , and the camera lifting structure  100  is fully accommodated inside the display device  200 . At this point, the camera lifting structure  100  is in the accommodated state. 
     Reference is made to  FIG.  15   .  FIG.  15    is a comparative schematic view of a display device  200  according to an embodiment of the present disclosure and a conventional display device  300 . The display device  200  with the camera lifting structure  100  of the present disclosure is illustrated at right side in  FIG.  15    while the conventional display device  300  is illustrated at left side. It is worth to note that, in the present disclosure, the sliding portions  130  slide along the first direction D1 and the elastic elements  120  compress and extend along the first direction D1, which makes the camera module  150  move towards or away from the rail bracket  110  along the second direction D2, and the camera lifting structure  100  switches between the accommodated state and the operation state correspondingly. In comparison, the conventional camera lifting structure  310  of the conventional display device  300  extend and retract the camera vertically with elastic elements compress and extend along the same direction. The dimension of the camera lifting structure  100  occupied within the display housing  210  of the display device  200  along the second direction D2 can be effectively reduced. To be specific, as shown in  FIG.  15   , the length LN occupied by the camera lifting structure  100  inside the display device  200  is apparently shorter than the length LO occupied by the conventional camera lifting structure  310  inside the display device  300 . Therefore, the display device  200  with the camera lifting structure  100  of the present disclosure installed has more inner space saved, which improves the flexibility in design and parts selection of the display device  200 . Moreover, damages caused by the camera lifting structure  100  conflicting with other internal parts during assembly and installation process can be avoided. 
     In conclusion, the aforementioned embodiments of the present disclosure have at least the following advantages: 
     (1) Since the movement of camera module towards or away from the rail bracket along the second direction to switch between the accommodated state and the operation state, corresponds to the sliding of the sliding portions along the first direction and the compression and extension of the elastic elements along the first direction, the dimension of the camera lifting structure disposed within the display housing of the display device along the second direction can be effectively reduced. As a result, when the camera lifting structure is installed within the display housing of the display device, the inner space for usage of the display device can be effectively saved. Moreover, damage of the camera lifting structure due to contact with other internal components can be avoided. 
     (2) When the main connecting rods rotate relative to the camera module and the sliding portions, the protruding portions at least partially located inside the slots of the auxiliary connecting rods are also moved inside the slots of the auxiliary connecting rods with respect to the rotation of the main connecting rods, such that the auxiliary connecting rods also rotate relative to the damping module. Since the damping module provides damping to the rotation of the auxiliary connecting rods, the rotation of the main connecting rods relative to the camera module and the sliding portions is also influenced by the damping effect. In this way, the speed at which the sliding portions slide towards each other or towards the fixing portions along the first direction and the speed at which the camera module moves towards or away from the rail bracket along the second direction are under control, and the movement of the camera module towards or away from the rail bracket along the second direction also becomes more stable. 
     (3) Since the cables pass through the annular structure and are protected by the annular structure, when the camera module moves along the second direction relative to the rail bracket, the cables connected between the camera and the display device will not entangle with or tug on other components of the display device or the camera lifting structure. Thus, damage or even fracture of the cables can be avoided. 
     Although the present disclosure has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. 
     It will be apparent to the person having ordinary skill in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the present disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of the present disclosure provided they fall within the scope of the following claims.