Patent Publication Number: US-2023152625-A1

Title: Backlight module and display device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Chinese Patent Application No. 202111351328.4, filed on Nov. 15, 2021, the entire contents of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to the display technical field, in particular to a backlight module and a display device. 
     BACKGROUND 
     At present, the commonly used backlight module for liquid crystal display (LCD) is a side-in backlight module. In this structure, the light guide plate and the light source bar are provided on the same side of the backplane and close to each other. Limited by the thickness and width of the light emitting diode (LED) lamp beads on the light source bar, thinning the frame of the display module will be restricted. After the light guide plate is heated and expanded, the distance between the light guide plate and the LED lamp beads will be shortened, which is easy to squeeze or damage the light source. 
     SUMMARY 
     The main objective of the present disclosure is to provide a backlight module, by providing a light input end of the light guide plate and a light source on a lower side of the backplane, aiming to not only achieve a narrower frame and ensure a better light output effect, but also avoid damage to the light source after the expansion of the light guide plate. 
     In order to achieve the above objectives, the present disclosure provides a backlight module includes a backplane, a light guide plate and a light source. The backplane includes a first surface and a second surface opposite to the first surface. The light guide plate includes a light output portion provided on the first surface and a bending portion provided with a light input end on the second surface, and an end of the light output portion facing the second surface of the backplane is bent and extended to form the bending portion. The light source is provided on the second surface and corresponds to a light input end face of the light input end. 
     In an embodiment, the bending portion includes a curved section and a straight section. The curved section is connected to the light output portion and the straight section and the straight section is the light input end and includes a surface parallel to a surface of the light output portion and the light input end face perpendicular to the surface of the light output portion. 
     In an embodiment, a side of the curved section away from the backplane is an arc or a broken line on a longitudinal section of the backlight module and/or a surface facing the backplane and formed by an enclosure of the light output portion and the bending portion is a U-shaped surface. 
     In an embodiment, at least a portion of the surface of the bending portion away from the backplane is provided with a first reflector and/or a reflective piece is provided between the light output portion and the backplane. 
     In an embodiment, a thickness of the bending portion is less than a thickness of the light output portion and/or an end face of the backplane facing the bending portion is a curved surface and/or the end face of the backplane facing the bending portion is coated with a protective layer. 
     In an embodiment, the present disclosure further provides a display device including a display panel provided on a light output side of the light output portion and a backlight module as described above. 
     In an embodiment, the display device further includes a bracket. The bracket includes a fixation portion installed on the second surface and a shading portion provided at an end of the fixation portion, and the shading portion extends towards the light source and covers a side of the light source away from the backplane. 
     In an embodiment, the display device further includes a middle frame. The middle frame includes a bottom portion and a side portion connected to an edge of the bottom portion. The bottom portion is supported on a surface of the shading portion away from the light source, and the side portion is attached to a surface of the bending portion away from the backplane. 
     In an embodiment, the display device further includes a main control board. The bracket further includes an installation portion provided at an another end of the fixation portion, and the main control board is installed on each surface of the installation portion and the shading portion away from the light source and electrically connected to the display panel and the light source. 
     In an embodiment, a second reflector is provided on a surface of the shading portion facing the light source and/or the display panel includes an array substrate and a color filter substrate opposite to the array substrate. A portion of the array substrate beyond the color filter substrate is electrically connected to the main control board through a chip on film, the chip on film is attached to and extends along a surface of the middle frame away from the light guide plate, and the middle frame is provided with a receiving groove for holding chips of the chip on film. 
     In the technical solution of the present disclosure, the backlight module includes the backplane, the light guide plate and the light source. The light guide plate includes the light output portion and the bending portion which an end of the light output portion bends and extends to form. The light output portion is provided on the first surface of the backplane, and the light source is provided on the second surface of the backplane. The bending portion is provided on a side face of the backplane, and the light input end is provided on the second surface of the backplane. The light emitted by the light source is received by the light input end face of the light input end on the second surface, then transmitted to the light output portion through total reflection and emitted from the light output side of the light output portion. The light guide plate provided with the bending portion and the light source provided on the second surface not only can reduce the restriction on the frame due to the size of the light source and can effectively realize a narrow frame, but also can make the distance between the light source and the light guide plate not too small when the light guide plate is heated and expanded. Thus, the light source is effectively protected from damage, and the extension space of the backplane is used to effectively reduce the thickness or the frame size. In addition, the bending portion is provided with the light input end provided on the second surface of the backplane. When the light source is directed to the light input end face, the light can smoothly enter the bending portion through the resistance of the light input end, which reduces the probability of direct reflection of the light directed to the bending arc and effectively ensure the light guide effect and the light output effect of the backlight module. Furthermore, the light input end also enables the light guide plate to be clamped on the edge of the backplane. Thus, the installation stability and relative positions of the light guide plate and the backplane are effectively ensured, and the structural stability of the backlight module is improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To illustrate the technical solutions according to the embodiments of the present disclosure or the related art more clearly, the accompanying drawings for describing the embodiments or the related art are introduced briefly in the following. Apparently, the accompanying drawings in the following description are only about some embodiments of the present disclosure, and persons of ordinary skill in the art can derive other drawings from the accompanying drawings without creative efforts. 
         FIG.  1    is a top view of a display device according to an embodiment of the present disclosure. 
         FIG.  2    is a cross-sectional view along line A-A of the display device shown in  FIG.  1   . 
         FIG.  3    is a cross-sectional view of a backlight module of the display device shown in  FIG.  2   . 
         FIG.  4    is a top view of a display device according to another embodiment of the present disclosure. 
         FIG.  5    is a cross-sectional view along line B-B of the display device shown in  FIG.  4   . 
         FIG.  6    is a top view of a display device according to yet another embodiment of the present disclosure. 
         FIG.  7    is a cross-sectional view along line C-C of the display device shown in  FIG.  6   . 
         FIG.  8    to  FIG.  10    are schematic views showing an assembly process of the display device shown in  FIG.  4   . 
     
    
    
     The realization of the objective, functional characteristics, and advantages of the present disclosure are further described with reference to the accompanying drawings. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The technical solutions of the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It is obvious that the embodiments described are only some rather than all of the embodiments of the present disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without creative efforts shall fall within the claimed scope of the present disclosure. 
     It should be noted that all the directional indications (such as up, down, left, right, front, rear . . . ) in the embodiments of the present disclosure are only used to explain the relative positional relationship, movement, or the like of the components in a certain posture (as shown in the drawings). If the specific posture changes, the directional indication will change accordingly. 
     In the present disclosure, unless otherwise clearly specified and limited, the terms “connected”, “fixed”, etc. should be interpreted broadly. For example, “fixed” can be a fixed connection, a detachable connection, or a whole; can be a mechanical connection or an electrical connection; may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication between two elements or the interaction relationship between two elements, unless specifically defined otherwise. For those of ordinary skill in the art, the specific meaning of the above-mentioned terms in the present disclosure can be understood according to specific circumstances. 
     Besides, the descriptions associated with, e.g., “first” and “second,” in the present disclosure are merely for descriptive purposes, and cannot be understood as indicating or suggesting relative importance or impliedly indicating the number of the indicated technical feature. Therefore, the feature associated with “first” or “second” can expressly or impliedly include at least one such feature. In addition, the technical solutions of the various embodiments can be combined with each other, but the combinations must be based on the realization of those skilled in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist, nor does it fall within the scope of the present disclosure. 
     The present disclosure provides a backlight module  100 . 
     As shown in  FIG.  1    to  FIG.  3   , in an embodiment of the present disclosure, the backlight module  100  includes a backplane  10 , a light source  20  and a light guide plate  30 . The backplane  10  includes a first surface  11  and a second surface  12  opposite to the first surface  11 . The light guide plate  30  includes a light output portion  31  provided on the first surface  11  and a bending portion  32  provided with a light input end on the second surface  12 , and an end of the light output portion  31  facing the second surface  12  of the backplane  10  is bent and extended to form the bending portion  32 . The light source  20  is provided on the second surface  12  and corresponds to a light input end face  3221  of the light input end. 
     In this embodiment, the backlight module  100  is a side-in backlight module  100 , which includes the backplane  10 , the light source  20  and the light guide plate  30 . The backplane  10  is shaped in a plate, and generally, shaped in a rectangular parallelepiped plate. The light source  20  can be a light bar, or a strip-shaped illuminant composed of a plurality of lamp beads  21 , and is installed on the second surface  12  of the backplane  10 , namely, the rear surface. In an embodiment, the light source  20  includes a base body and a plurality of lamp beads  21  which are LED lamps with low cost and stable light output and are installed on the backplane  10  through an integrated substrate  22  to improve assembly efficiency. The base may be a flexible circuit board or a printed circuit board, which is not only for fixation, but also for realizing electrical connection and supplying power to the lamp beads  21 , to effectively reduce assembly components. It can be understood that, the light guide plate  30  includes the light output portion  31  and the bending portion  32 . The light output portion  31  provided with a light output side, is provided on the first surface  11 , namely, a front surface of the backplane  10 . The bending portion  32  is provided on an end face of the light output portion  31 , and is bent and extended towards the second surface  12  of the backplane  10 . The bending portion  32  is bent around an edge of the backplane  10 , thereby effectively reducing a gap between the bending portion  32  and the backplane  10  and reducing a frame size. Both the light source  20  and the light guide plate  30  can be fixed to the backplane  10  by bonding, which is simple and convenient. The adhesive material can be liquid glue, solid glue, or a fixing adhesive tape such as a single-sided adhesive or a double-sided adhesive or the like, to achieve stable installation, reduce the occupied space, and effectively decrease the thickness of the backlight module  100 . 
     To improve the utilization rate of light, the light source  20  is provided close to the edge of the backplane  10 , and the bending portion  32  is bent at least 180 degrees. Thus, when the bending portion  32  is bent 180 degrees, the light input end face  3221  is just opposite to the light source  20  and part of the light input end face  3221  is placed on the second surface  12  of the backplane  10 . That is, the bending portion  32  is provided with a surface parallel to the backplane  10  and extends towards the light source  20 . The light input end face  3221  of the light guide plate  30  faces the light output side of the light source  20 . The light emitted by the light source  20  enters the bending portion  32  and transmitted to the light output portion  31  through total reflection, then the light is emitted from an upper surface of the light output portion  31  to realize a surface light source  20 . In addition, the light source  20  and the light output portion  31  are separated by the backplane  10 , which can further reduce the heat radiation influence of the light source  20  on the light output portion  31 , thereby prolonging the service life of the light guide plate  30 . Furthermore, to further improve the safety, the lamp beads  21  are spaced apart from the bent portions by a certain safety distance. The safety distance can be independent of the frame size. Thus, the set value of the safety distance can be larger to effectively avoid the extrusion of the light guide plate  30  due to thermal expansion and improve the protection. 
     In the technical solution of the present disclosure, the backlight module  100  includes the backplane  10 , the light guide plate  30  and the light source  20 . The light guide plate  30  includes the light output portion  31  and the bending portion  32  formed by the end of the light output portion  31  bending and extending. The light output portion  31  is provided on the first surface  11  of the backplane  10 , and the light source  20  is provided on the second surface  12  of the backplane  10 . The bending portion  32  is provided on a side face of the backplane  10 , and the light input end is provided on the second surface  12  of the backplane  10 . The light emitted by the light source  20  is received by the light input end face  3221  of the light input end. The light guide plate  30  provided with the bending portion  32  and the light source  20  provided on the second surface  12  can not only reduce the restriction on the frame due to the size of the light source  20  and effectively realize a narrow frame, but also make the distance between the light source  20  and the light guide plate  30  not too small when the light guide plate  30  is heated and expanded. Thus, the light source  20  is effectively protected from damage, and the extension space of the backplane  10  is used to effectively reduce the thickness or the frame size. In addition, the bending portion  32  is provided with the light input end placed on the second surface  12  of the backplane  10 . When the light source  20  is directed to the light input end face  3221 , the light can smoothly enter the bending portion  32  through the resistance of the light input end, which reduces the probability of direct reflection of the light directed to the bending arc and effectively ensures the light guide effect and the light output effect of the backlight module  100 . Furthermore, the light input end also enables the light guide plate  30  to be clamped on the edge of the backplane  10 . Thus, the installation stability and relative positions of the light guide plate  30  and the backplane  10  are effectively ensured, and the structural stability of the backlight module  100  is improved. 
     As shown in  FIG.  3   , in an embodiment, the bending portion  32  includes a curved section  321  and a straight section  322 . The curved section  321  is connected to the light output portion  31  and the straight section  322 . The straight section  322  is the light input end and includes a surface parallel to a surface of the light output portion  31  and the light input end face  3221  perpendicular to the surface of the light output portion  31 . 
     In this embodiment, the bending portion  32  includes the curved section  321  and the straight section  322 . The curved section  321  is provided on the side face of the backplane  10  and is configured to transitionally connect the light output portion  31  and the straight section  322 . The straight section  322  provided on the second surface  12 , namely, a lower surface of the backplane  10 , is the light input end and includes the surface parallel to the light output portion  31  and the light input end face  3221  perpendicular to the surface of the light output portion  31 , that is, the straight section  322  is a rectangle. In this way, the light emitted by the light source  20  can be received by the straight section  322  as much as possible, which makes the amount of light received by the straight section  322  close to that received by the current light guide plate  30  shaped in a plate. Thus, on the basis of reducing the frame size, a light guide amount and a light guide effect of the light guide plate  30  are not affected. 
     As shown in  FIG.  4    to  FIG.  7   , in an embodiment, a side of the curved section  321  away from the backplane  10  is an arc or a broken line on a longitudinal section of the backlight module  100 , and/or a surface facing the backplane  10  and formed by an enclosure of the light output portion  31  and the bending portion  32  is a U-shaped surface. 
     The light output portion  31  is bent and extended to form the bending portion  32 , and the shape of the bending portion  32  is not limited. In an embodiment, on the longitudinal section of the backlight module  100 , the side of the curved section  321  away from the backplane  10  may be an arc, such as a circular arc, to make the curved section  321  provided with a smooth arc surface which is convenient for processing and assembly. Or the side of the curved section  321  away from the backplane  10  is a broken line, for example, the broken line is composed of two straight lines which are connected to each other. Therefore, a tapered surface is provided on the curved section  321  and the material of the curved section  321  is reduced. Or the broken line is composed of multiple straight lines connected end to end, and the curved section  321  is provided with multiple planes connected to each other. The size can be designed according to the actual situation, to facilitate the assembly and improve the installation stability. 
     On the basis that the surface of the curved section  321  away from the backplane  10  is an arc surface or a tapered surface, since the bending portion  32  is bent at least 180 degrees, the surface facing the backplane  10  and formed by the enclosure of the light output portion  31  and the bending portion  32  is configured to be U-shaped to better match the peripheral edge of the backplane  10 , and the accuracy and stability of the installation are further improved. 
     As shown in  FIG.  3   , in an embodiment, at least a portion of the surface of the bending portion  32  away from the backplane  10  is provided with a first reflector  40 , and/or a reflective piece  50  is provided between the light output portion  31  and the backplane  10 . 
     In this embodiment, to avoid light leakage, the first reflector  40  is provided on the surface of the bending portion  32  away from the backplane  10 . The first reflector  40  can be a reflective coating layer or the reflective piece  50 , which is attached to a surface of the bending portion  32  and can further reflect the light transmitted from the bending portion  32  to make the light back to the light guide plate  30 . Not only a light output amount is improved, but also an efficiency of the light source  20  is improved. The first reflector  40  may be provided on a whole surface of the bending portion  32  away from the backplane  10 , such as each surface of the curved section  321  and the straight section  322  away from the backplane  10 . Therefore, the light output amount can be increased to the greatest extent. Of course, the first reflector  40  may also be provided in a partial area of the bending portion  32 , for example, only on the surface of the curved section  321  away from the backplane  10 . 
     It can be understood that, after passing through the light input end face  3221  and entering the curved section  321 , the light will be totally reflected, or partially transmitted and reflected. Then the light enters into the light output portion  31 , and is reflected and transmitted on an upper surface and a lower surface of the light output portion  31 . To ensure that the light is all reflected and emitted from a light output side of the upper surface, the reflective piece  50  is provided between the light guide plate  30  and the backplane  10 . The material of the reflective piece  50  is generally a composite material of PET and TiO, which performs a good reflection effect, prevents the light from being emitted from the lower surface of the light output portion  31  and effectively increases the light output amount. Of course, in another embodiment, the material of the reflective piece  50  may also have a metal reflection structure or the like. 
     As shown in  FIG.  2    and  FIG.  3   , in an embodiment, a thickness of the bending portion  32  is less than a thickness of the light output portion  31 , and/or an end face of the backplane  10  facing the bending portion  32  is a curved surface, and/or the end face of the backplane  10  facing the bending portion  32  is coated with a protective layer  60 . 
     To further facilitate bending, the thickness of the light guide plate  30  is non-uniform, that is, the thickness of the bending portion  32  is less than the thickness of the light output portion  31 . Reducing the thickness of the bending portion  32  can facilitate bending and processing the bending portion  32 , which ensures a bending effect and improves a structural stability of the bending portion  32 . Of course, to further improve the bending effect, the thickness of the bending portion  32  is gradually decreased along a direction from an end close to the light output portion  31  to the light input end face  3221 . Thus stress-concentrated areas and dead corners can be avoided, and a structural strength and a light guiding effect of the bending portion  32  can be ensured. In addition, a restriction on a design of the narrow frame from the bending portion  32  can be further reduced, and the frame size can be reduced. Of course, in another embodiment, the thickness of the bending portion  32  can also be reduced in a stepped or irregular manner. 
     Since the bending portion  32  bypasses an edge of the backplane  10  and forms the light input end face  3221  facing the light source  20 , an end face of the backplane  10  facing the bending portion  32  is configured to be a curved surface to prevent a surface of the light guide plate  30  from being scratched or damaged by the corners of the backplane  10 . For example, the corners of the backplane  10  are provided with chamfers, or end faces of the backplane  10  are provided with arc surfaces or the like. Therefore, the backplane  10  is provided with a smooth contact surface, which not only effectively improves the protection for the bending portion  32 , but also improves the product yield. Of course, in another embodiment, a protective layer  60  may be coated on the end face of the backplane  10 , and the protective layer  60  may be an anti-scratch film layer or a wear-resistant layer or the like. Moreover, the friction damage between the backplane  10  and the light guide plate  30  can also be reduced, to improve the product performance. In an embodiment, when the reflective piece  50  is provided between the light output portion  31  and the backplane  10 , the protective layer  60  can be extended towards the first surface  11  to abut against the reflective piece  50  and towards the second surface  12  to abut against the light source  20  to achieve a protection on the largest area. 
     Of course, in another embodiment, the end face of the backplane  10  may be a curved surface coated with a protective layer  60  to obtain a better protective effect. 
     As shown in  FIG.  3   , in addition, to improve a light output efficiency and a light output effect, the backlight module  100  further includes an optical control component  70 , namely, an optical film, which is provided on the light output portion  31  to form an output light with better effect. The optical control component  70  may be a prism sheet, a brightening sheet and a diffusion plate or the like. The prism sheet can improve a light uniformity, and the brightening sheet can increase a brightness of the output light, and the diffusion plate can increase an output angle of the output light to ensure that an edge of the light output portion  31  can also receive enough light. Therefore, the brightness of the edge is improved and a more uniform and stable light source  20  is provided. Of course, a plurality of optical control components  70  stacked in sequence can also be provided to further improve the uniformity and stability of the output light of the backlight module  100 . 
     As shown in  FIG.  4    to  FIG.  7   , the present disclosure provides a display device  900  including the backlight module  100  as described above and a display panel  800  provided on a light output side of the light output portion  31 . Since the backlight module  100  of the display device  900  in the present disclosure applies the backlight module  100  of any of the above embodiments, the beneficial effects brought by the above embodiments will not be repeated here. 
     As shown in  FIG.  2    and  FIG.  5   , in an embodiment, the display device  900  further includes a bracket  91 , which includes a fixation portion  911  installed on the second surface  12  and a shading portion  912  provided at an end of the fixation portion  911 . The shading portion  912  extends towards the light source  20  and covers a side of the light source  20  away from the backplane  10 . 
     In this embodiment, since the light source  20  is provided on the second surface  12 , namely, hangs upside down on the backplane  10 , the light emitted by the light source  20  will direct along a direction where is away from the backplane  10  and the bracket  91  is fixed to the backplane  10 . The bracket  91  is provided with the shading portion  912  which can cover the side of the light source  20  away from the backplane  10 . That is, the fixation portion  911  fixed on the second surface  12  of the backplane  10  and a substrate  22  of the light source  20  are set at intervals. One end of the shading portion  912  shaped in a sheet or a plate is connected to a surface of the fixation portion  911  away from the backplane  10 , and another end extending towards the light source  20  is provided on a lower surface of the light source  20 , which can completely cover the light source  20  to achieve a shading effect and prevent the light source  20  from leaking from the back of the backlight module  100 . The fixation portion  911  may be fixed to the backplane  10  by bonding or welding, or may be connected to the backplane  10  by a removable way such as clamping or plugging. The bracket  91  can be made of metal to enable the bracket  91  to have a better shading effect and facilitate the heat dissipation of the light source  20 . 
     Of course, in an embodiment, the shading portion  912  can also be abutted against the light source  20 , namely, abutted against the lamp beads  21 , to provide a certain supporting force for the light source  20  and further ensure the structural stability of the backlight module  100 . 
     In an embodiment, a second reflector  914  is provided on a surface of the shading portion  912  facing the light source  20 . Under a condition that a light emitted by the light source  20  towards the back of the backplane  10  is effectively covered, to effectively utilize the light, the second reflector  914  is provided between the shading portion  912  and the light source  20  to reflect the light, and increase a probability that the light enters the light guide plate  30  and a utilization rate of the light source  20 . 
     As shown in  FIG.  2    and  FIG.  5   , in an embodiment, the display device  900  further includes a middle frame  92 . The middle frame  92  includes a bottom portion  921  and a side portion  922  connected to an edge of the bottom portion  921 . The bottom portion  921  is supported on a surface of the shading portion  912  away from the light source  20 , and the side portion  922  is attached to a surface of the bending portion  32  away from the backplane  10 . 
     Of course, to make the installation of the light source  20  and the light guide plate  30  more stable, the display device  900  also includes the middle frame  92 . The middle frame  92  includes the bottom portion  921  and the side portion  922 , both of which are provided at an angle. The side portion  922  provided at a side of the bending portion  32  away from the backplane  10  can laterally limit the bending portion  32 . Therefore, an inner surface of the side portion  922  matches an outer surface of the bending portion  32 , and an installation stability of the first reflector  40  is ensured. The side portion  922  can also support the display panel  800 , so that a certain light output distance is reserved between the light guide plate  30  and the display panel  800 . Specifically, the bottom portion  921  is perpendicular to the side portion  922  and extends towards a side where the light source  20  is provided, which can limit the bending portion  32  and the light source  20  in the longitudinal direction. In an embodiment, the bottom portion  921  can abut against and support the shading portion  912  to further improve the compactness and stability of the structure. 
     Both the side portion  922  and the bottom portion  921  can be made of plastic or metal. When the material is plastic, the side portion  922  and the bottom portion  921  can be integrated by injection molding, and when the material is metal, the side portion  922  and the bottom portion  921  can be punched and then bent, which not only provides the structure with good strength and good stability, but also plays a better support and protection role. Of course, in an embodiment, the light source  20  can be provided on the middle frame  92 , that is, installed on a surface of the bottom portion  921  facing the light guide plate  30 , thus the material of the bracket  91  can be saved. Then the second reflector  914  can be provided on the surface of the bottom facing the light source  20  to improve the utilization rate of the light. 
     As shown in  FIG.  5    and  FIG.  7   , the display device  900  further includes a main control board  93 . In an embodiment, the bracket  91  further includes an installation portion  913  provided at another end of the fixation portion  911 , and the main control board  93  is installed on each surface of the installation portion  913  and the shading portion  912  away from the light source  20  and electrically connected to the display panel  800  and the light source  20 . 
     It can be understood that the display device  900  further includes the main control board  93  to provide the display panel  800  with display screen data and scanning voltages. The main control board  93  is installed on a lower surface of the backplane  10 . The bracket  91  further includes the installation portion  913  which is also shaped in a plate and provided at an end of the fixation portion  911  away from the shading portion  912 . The main control board  93  is installed on each surface of the installation portion  913  and the shading portion  912  away from the light source  20 , and is set at an interval from the middle frame  92 , which can simplify and integrate a structure for covering the light source  20  with a structure for fixing the main control board  93  to improve the integration degree of the display device  900 . In addition, the shading portion  912  and the installation portion  913  are integrated to install the main control board  93 , which can improve the structural stability and reduce an area occupied by the bracket  91 . 
     The shading portion  912  and the installation portion  913  both extend for a certain length in opposite directions towards a side away from the backplane  10 . Therefore, an avoidance cavity is formed by an enclosure of the shading portion  912 , the installation portion  913  and the backplane  10 . When being installed on the installation portion  913  and the shading portion  912 , part of the main control board  93  faces the avoidance cavity, which can effectively improve a heat dissipation effect. Furthermore, the installation portion  913  and the shading portion  912  are integrated, and a material of the integration is a metal sheet, which can be produced by bending easily and conveniently. The material can not only effectively improve a processing efficiency, but also further improve the heat dissipation effect. In addition, the metal bracket  91  can be connected to each ground signal of the main control board  93  and the backplane  10 , which is beneficial to connecting to ground. 
     Of course, in another embodiment, the main control board  93  can also be installed on a surface of the shading portion  912  away from the light source  20 , or only installed on a surface of the installation portion  913  away from the backplane  10 . 
     As shown in  FIG.  2    and  FIG.  5   , in an embodiment, the display device  900  includes an array substrate  801  and a color filter substrate  802  opposite to the array substrate  801 . A portion of the array substrate  801  beyond the color filter substrate  802  is electrically connected to the main control board  93  through a chip on film  94 , and the chip on film  94  is attached to and extends along a surface of the middle frame  92  away from the light guide plate  30 . The middle frame  92  is provided with a receiving groove  9221  for holding chips of the chip on film  94 . 
     It can be understood that the array substrate  801  is provided with a thin film transistor that controls each pixel to be turned on, thereby an edge of the array substrate  801  is provided with a fan-out structure to make the array substrate  801  electrically connected to the main control board  93  through the chip on film  94 . The chip on film  94  includes a film base  941  and a wafer  942  provided thereon. To further reduce the width of the frame, the receiving groove  9221  is provided on the surface of the middle frame  92  away from the light guide plate  30 , and the film base  941  is attached to and extends along the surface of the middle frame  92 . Furthermore, the wafer  942  is hold by the receiving groove  9221 . Therefore, a lateral width occupied by the chip on film  94  can be minimized and a narrower frame is further realized. 
     Specifically, assembling the display device  900  includes the following steps. 
     As shown in  FIG.  8   , the light guide plate  30  and the light source  20  are installed firstly. The light guide plate  30  is installed on the backplane  10 , and the middle frame  92  is correspondingly installed on one side of the bending portion  32 . The light source  20  is installed on the second surface  12  of the backplane  10  and corresponds to the light input end face  3221  of the bending portion  32 . This way can ensure that after the light guide plate  30  is installed stably, the light source  20  is installed in a targeted manner, thereby the accuracy of the installation position of the light source  20  is improved, and the safety distance between the light source  20  and the light guide plate  30  can be reasonably designed to reduce the damage probability. In addition, when installing the reflective piece  50  and the optical film, the reflective piece  50  is firstly bonded, then the light guide plate  30  is secondly bonded, and finally the optical film is installed over the light guide plate  30 . When installing the first reflector  40  and the protective layer  60 , the protective layer  60  is provided on the backplane  10  before installing the light guide plate  30 , to reduce the damage to the light guide plate  30  and improve the protection. Then the first reflection piece is clamped between the bending portion  32  and the middle frame  92 . 
     As shown in  FIG.  9   , the bracket  91  is installed secondly. The fixation portion  911  is adhered to the second surface  12  of the backplane  10 , and the shading portion  912  is placed below the light source  20 . Of course, the fixation portion  911  can also be fixed to the backplane  10  through thread. According to the position of the light source  20 , the fixed position of the fixation portion  911  is determined, which can ensure that the shading portion  912  completely covers the light source  20  and improve the shading effect. When installing a second reflector  914 , the second reflector  914  is first attached to an upper surface of the shading portion  912 , and then the fixation portion  911  is installed. In this way, not only the convenience can be improved, but also the convenient installation of the bracket  91  can be prevented from being interfered by the shade between the shading portion  912  and the light source  20 . 
     As shown in  FIG.  10   , the display panel  800  is installed to the backlight module  100  thirdly. The array substrate  801  and the color filter substrate  802  are pressed against each other. An end of the chip on film  94  is connected to the edge of the array substrate  801 , and another end is connected to the main control board  93 . Then, the edge of the array substrate  801  is overlapped to an upper surface of the middle frame  92 , and the color filter substrate  802  is provided on the array substrate  801 . The chip on film  94  is attached to and extended along the outer surface of the middle frame  92 . Finally the main control board  93  is placed under the bracket  91  and fixed by bonding or welding. In this way, the electrical connection can be finished in advance under the condition of convenient placement, and then the chip on film  94  can be attached to the middle frame  92 , thereby further improving the convenience of assembly, and the occupation space and the influence of the display panel  800  on other components can be reduced. 
     Finally, a front frame  96  and a rear frame  95  are installed. The display panel  800  further includes the front frame  96  and the rear frame connected to each other. To form a stable installation structure and realize a narrow frame structure of the display device  900 , the front frame  96  covers an edge of the display panel  800 , and the rear frame  95  covers the main control board  93 , the middle frame  92  and the back of the backplane  10 . 
     As shown in  FIG.  5    and  FIG.  7   , in addition, when the color filter substrate  802  is provided towards a side of the light guide plate  30 , the array substrate  801  overlaps the upper surface of the middle frame  92 , and the front frame  96  may not cover the edge of the array substrate  801 , thereby realizing a borderless structure of the display device  900 . 
     The above are only preferred embodiments of the present disclosure and are not to limit the scope of the present disclosure. Under the concept of the present disclosure, any equivalent structural transformations made by using the contents of the description and drawings of the present disclosure, or any direct or indirect application to other related technical fields is included in the scope of the claims.