FIELD OF THE INVENTION 
       [0001]    The invention belongs to the field of display technology, and particularly relates to a position-limiting structure for a backlight module, a backlight module and a display device. 
       BACKGROUND OF THE INVENTION 
       [0002]    An existing backlight module generally includes a backplane, a light source (generally a LED lamp) arranged on an edge of the backplane, and a light-guiding plate arranged above the backplane, wherein the backplane and the light-guiding plate are fixed to each other by using double-sided adhesive tape at an edge of the backplane which is not provided with the LED lamp. 
         [0003]    The inventor found that there are at least the following problems existing in the prior art: when the backlight module is subjected to Aging (High temperature and high humidity test), the adhesive of the double-sided adhesive tape will experience thermal expansion and contraction, so the light-guiding plate is pulled, which will lead to a gap between the light-guiding plate and the LED lamp at a light-incoming side of the light-guiding plate, and accordingly result in an optical defect; in addition, it is difficult to meet higher alignment requirements by manual adherence of the double-sided adhesive tape. For example, when a distance between two LED lamps is increased, and the number of the LED lamps is decreased to save the cost, if there is an alignment error in the light-guiding plate, the Hot-spot phenomenon will occur, which will result in an image defect and an optical defect. 
       SUMMARY OF THE INVENTION 
       [0004]    In view of the problem in the prior art that an alignment error occurs in the light-guiding plate due to the fact that the double-sided adhesive tape is adhered to fix the backplane and the light-guiding plate, the invention provides a position-limiting structure for a backlight module, a backlight module and a display device. 
         [0005]    Technical solutions employed to solve the problem of the invention are as follows: 
         [0006]    A position-limiting structure for a backlight module is made of an elastic material, and is configured to be connected to a backplane; the position-limiting structure includes a position-limiting part, which is arranged outside an edge at at least one non light-incoming side of a light-guiding plate and is configured to fix the light-guiding plate to the backplane. 
         [0007]    Preferably, the position-limiting part fixes the light-guiding plate to the backplane by inserting into an opening in the backplane. 
         [0008]    Preferably, the position-limiting structure further includes a fixing part connected to the position-limiting part, and the fixing part is configured to be stuck at the outside of the opening in the backplane. 
         [0009]    Preferably, the position-limiting part is vertical to the fixing part. 
         [0010]    Preferably, the position-limiting structure is integrally formed. 
         [0011]    Preferably, a cross section of the position-limiting structure in the direction vertical to the backplane is shaped of a “T” letter, and the horizontal part of the “T” letter is the fixing part, and the vertical part of the “T” letter is the position-limiting part. 
         [0012]    Preferably, the position-limiting structure is made of silica gel or plastic. 
         [0013]    The invention further provides a backlight module, including a backplane, a light-guiding plate and the above position-limiting structure. 
         [0014]    Preferably, a bottom side of the light-guiding plate is a non light-incoming side, and the position-limiting structure fixes the light-guiding plate to the backplane at least via the bottom side. 
         [0015]    Preferably, a left side and a right side of the light-guiding plate are non light-incoming sides, and the position-limiting structure fixes the light-guiding plate to the backplane at least via the left side and the right side. 
         [0016]    Preferably, at least one opening is provided in the backplane at a position corresponding to the position-limiting structure, and in the direction vertical to the light-guiding plate, the position-limiting part of the position-limiting structure is inserted into the at least one opening from one side away from the light-guiding plate so as to fix the light-guiding plate to the backplane. 
         [0017]    The invention further provides a display device, including the above backlight module. 
         [0018]    The position-limiting structure for a backlight module of the invention is made of an elastic material, and includes the position-limiting part, which is arranged outside an edge at at least one non light-incoming side of the light-guiding plate and is configured to fix the light-guiding plate to the backplane. When the position-limiting structure is applied to a backlight module, the position-limiting part will reliably fix the light-guiding plate to the backplane and thus they are not easy to loose so that the position of the light-guiding plate can be precisely defined, and when a high temperature and high humidity test is performed, regardless heating or cooling, the position-limiting part can precisely define the position of the light-guiding plate, which will not result in an alignment error in the light-guiding plate, and accordingly will not result in the image defect, the optical defect or the like. The backlight module including the above position-limiting structure of the invention is applicable to various display devices. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a schematic view of a position-limiting structure according to a second embodiment of the invention; 
           [0020]      FIG. 2  is a schematic view of a backlight module according to a third embodiment of the invention; and 
           [0021]      FIG. 3  is a schematic view of the backlight module according to the third embodiment of the invention. 
       
    
    
     REFERENCE NUMERALS 
       [0022]      1 . position-limiting structure;  11 . position-limiting part;  12 . fixing part;  2 . light-guiding plate;  3 . backplane. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0023]    To make those skilled in the art better understand the technical solutions of the present invention, the invention will be described below in detail with reference to the accompanying drawings and the following embodiments. 
       First Embodiment 
       [0024]    The embodiment provides a position-limiting structure for a backlight module, and the position-limiting structure is made of an elastic material and is configured to be connected to a backplane; the position-limiting structure includes a position-limiting part, which is arranged outside an edge at at least one non light-incoming side of the light-guiding plate and is configured to fix the light-guiding plate to the backplane. 
         [0025]    The position-limiting structure for a backlight module of the invention is made of an elastic material, and includes the position-limiting part, which is arranged outside an edge at at least one non light-incoming side of the light-guiding plate and is configured to fix the light-guiding plate to the backplane, and when the position-limiting structure is applied to a backlight module, the position-limiting part will reliably fix the light-guiding plate to the backplane and thus they are not easy to loose so that the position of the light-guiding plate can be precisely defined, which will not result in the image defect, the optical defect or the like. The backlight module including the above position-limiting structure of the invention is applicable to various display devices. 
       Second Embodiment 
       [0026]    As shown in  FIGS. 1-3 , the embodiment provides a position-limiting structure  1  for a backlight module, which is made of an elastic material and is configured to be connected to a backplane  3 ; the position-limiting structure  1  includes a position-limiting part  11 , which is arranged outside an edge at at least one non light-incoming side of a light-guiding plate  2  and is configured to fix the light-guiding plate  2  to the backplane  3 . 
         [0027]    The position-limiting structure  1  of the embodiment is made of the elastic material, and includes the position-limiting part  11 , which is arranged outside the edge at the at least one non light-incoming side of the light-guiding plate  2  and is configured to fix the light-guiding plate  2  to the backplane  3 , and when the position-limiting structure  1  is applied to a backlight module, the position-limiting part  11  will precisely define the position of the light-guiding plate  2 , and reliably fix the light-guiding plate  2  to the backplane  3  and thus they are not easy to loose so that the light-guiding plate  2  is tightly fixed to the backlight  3 , and even after Aging is performed, the light-guiding plate  2  is not moved and thus the position of the light-guiding plate  2  can be precisely defined, which will not result in the image defect, the optical defect or the like. In addition, since the light-guiding plate  2  is tightly fixed, even when a distance between two LED lamps is increased, so the number of the LED lamps is decreased, the Hot-spot phenomenon will not occur, and an image defect and an optical defect will not occur. The backlight module including the above position-limiting structure of the invention is applicable to various display devices. 
         [0028]    Preferably, as shown in  FIG. 2 , the position-limiting part  11  fixes the light-guiding plate  2  to the backplane  3  by inserting into an opening in the backplane  3 . 
         [0029]    That is, the opening in the backplane  3  is used to define the position of the position-limiting part  11  so as to make the light-guiding plate  2  stuck and fix the light-guiding plate  2 . 
         [0030]    Preferably, as shown in  FIGS. 1-3 , the position-limiting structure  1  further includes a fixing part  12  connected to the position-limiting part  11 , and the fixing part  12  is configured to be stuck at the outside of the opening in the backplane  3  and cooperate with the position-limiting part  11  so as to make the light-guiding plate  2  fixed to the backplane  3 . 
         [0031]    That is, after the position-limiting part  11  is inserted into the opening in the backplane  3 , the fixing part  12  will be tightly stuck at the outside of the opening in the backplane  3  so as to reliably fix the light-guiding plate  2  to the backplane  3 . For example, as shown in  FIG. 2 , after the position-limiting part  11  is inserted into the opening in the backplane  3 , the fixing part  12  will be tightly stuck at the outside of the opening in the backplane  3  so that the light-guiding plate  2  can obtain a reliable support to be fixed to the backplane reliably. 
         [0032]    Preferably, as shown in  FIG. 1 , the position-limiting part  11  is vertical to the fixing part  12 . 
         [0033]    Preferably, the position-limiting structure  1  is integrally formed. 
         [0034]    Preferably, the cross section of the position-limiting structure  1  in the direction vertical to the backplane  3  is shaped of a “T” letter, wherein the horizontal part of the “T” letter is the fixing part  12 , and the vertical part of the “T” letter is the position-limiting part  11 . 
         [0035]    That is, as shown in  FIG. 1 , as for the “T” shaped position-limiting structure  1 , the “I” shaped position-limiting part  11  is configured to be inserted into the opening in the backplane  3 , and the “         ” shaped fixing part  12  is stuck at the outside of the opening in the backplane  3 , so that the light-guiding plate  2  is reliably fixed to the backplane  3 . 
         [0036]    Preferably, the position-limiting structure  1  is made of silica gel or plastic. 
         [0037]    That is, the position-limiting structure  1  is made of silica gel or plastic, and in this case, when the backlight module is subjected to Aging, even the position-limiting structure  1  experiences slight deformation, an unrecoverable deformation due to the stress accumulation can be avoided after cooling. 
       Third Embodiment 
       [0038]    The embodiment provides a backlight module, including a backplane  3 , a light-guiding plate  2  and the position-limiting structure  1  in the second embodiment. 
         [0039]    Preferably, as shown in  FIG. 2 , the bottom side of the light-guiding plate  2  is a non light-incoming side, and the position-limiting structure  1  supports the light-guiding plate  2  at least via the bottom side so that the light-guiding plate  2  is fixed to the backplane  3 . 
         [0040]    That is, the position-limiting structure  1  is in contact with the bottom side of the light-guiding plate  2 , a backlight source such as a LED lamp is arranged at the top side of the light-guiding plate  2 , and thus the position-limiting structure  1  can hold up the light-guiding plate  2  so as to make it fixed to the backplane  3 . Alternatively, a backlight source such as a LED lamp is arranged at the top side of the light-guiding plate  2 , and the position-limiting structure  1  is in contact with the left side and the right side of the light-guiding plate  2  to make the light-guiding plate  2  stuck so that the light-guiding plate  2  is fixed to the backplane  3 . 
         [0041]    Preferably, an opening is provided in the backplane  3  at a position corresponding to the position-limiting structure  1 , and in the direction vertical to the light-guiding plate  2 , the position-limiting part  11  of the position-limiting structure  1  is inserted into the opening from one side away from the light-guiding plate  2  to fix the light-guiding plate  2 . 
         [0042]    That is, as shown in  FIG. 3 , after the position-limiting structure  1  is inserted into the opening so that the light-guiding plate  2  is fixed to the backplane  3 , from one side of the backplane  3  away from the light-guiding plate  2 , only the fixing part  12  can be seen, and the position-limiting part  11  is inserted into the opening from outside to inside so that the light-guiding plate  2  is fixed to the backplane  3 . 
         [0043]    Obviously, various modifications may be made to the above embodiments, for example, the length of the position-limiting structure  1  in the direction parallel to the light-guiding plate  2  can be changed according to different requirements; a plurality of openings can be provided in the backplane  3  at corresponding positions, and a plurality of position-limiting structures  1  are respectively inserted into the plurality of openings so that the light-guiding plate  2  is fixed to the backplane  3 . 
       Fourth Embodiment 
       [0044]    The embodiment provides a display device, which includes any one of the above backlight modules. The display device may be any product or component with display function such as a liquid crystal display panel, electronic paper, a mobile phone, a tablet computer, a TV, a display, a notebook computer, a digital image frame and a navigator. 
         [0045]    It should be understood that, the above embodiments are only exemplary embodiments used to explain the principle of the present invention and the protection scope of the present invention is not limited thereto. The person skilled in the art can make various variations and modifications without departing from the spirit and scope of the present invention, and these variations and modifications should be considered to belong to the protection scope of the invention.
The invention provides a position-limiting structure for a backlight module, a backlight module and a display device, belongs to the field of display technology, and can solve the problem in the prior art that an alignment error occurs in the light-guiding plate due to the fact that the double-sided adhesive tape is adhered to fix the backplane and the light-guiding plate. The position-limiting structure for a backlight module of the invention is made of an elastic material, and is configured to be connected to the backplane; the position-limiting structure includes the position-limiting part, which is arranged outside an edge at least one non light-incoming side of the light-guiding plate and is configured to fix the light-guiding plate to the backplane.