Patent Publication Number: US-2011069251-A1

Title: Liquid crystal display device, backlight module, and method of assembling a backlight module

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority of Taiwanese Application No. 098131912, filed on Sep. 22, 2009. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a liquid crystal display device, more particularly to a liquid crystal display device that is easy to assemble. 
     2. Description of the Related At 
     Referring to  FIG. 1 , a conventional liquid crystal display device  1  generally includes a backlight module  11 , a liquid crystal module  12 , a frame  13  and a bezel  14 . The liquid crystal module  12  is disposed on the backlight module  11 , and the frame  13  is disposed between the backlight module  11  and the liquid crystal module  12 . The bezel  14  is sleeved on the liquid crystal module  12  and is connected to the backlight module  11 . The backlight module  11  includes a back plate  111 , a reflector piece  112 , a light guide plate  113 , a pair of lamp tubes  114 , a pair of lampshades  115 , and a plurality of optical films  116 . The reflector piece  112 , the light guide plate  113  and the optical films  116  are stacked on the back plate  111  in sequence. The lamp tubes  114  and the lampshades  115  are installed adjacent to opposite sides of the light guide plate  113 . 
     Since the backlight module  11  of the liquid crystal display device  1  includes many components, an assembly procedure of the backlight module  11  is complex and time-consuming. Therefore, ways to improve the backlight module  11  to simplify the assembly procedure of the liquid crystal display device  1  are constantly sought by those in the industry. 
     SUMMARY OF THE INVENTION 
     Therefore, an object of the present invention is to provide a liquid crystal display device that can be assembled at lower costs. 
     The liquid crystal display device of the present invention includes a backlight module, a liquid crystal panel, and a bezel. The backlight module includes aback plate unit, a reflector unit, a light guide plate, and first and second light sources. The back plate unit includes first and second back plates. The first back plate has a first plate body with opposite first and second edge parts, and a first side part structure connected to the first edge part of the first plate body. The first side part structure defines a first receiving space for receiving the first light source, and the first receiving space opens toward the second edge part of the first plate body. The second back plate has a second plate body with opposite first and second edge parts, and a second side part structure connected to the first edge part of the second plate body. The second side part structure defines a second receiving space for receiving the second light source, and the second receiving space opens toward the second edge part of the second plate body. The second back plate is connected to the first back plate in a manner that the first and second side part structures are opposite to each other. The reflector unit is disposed on the first and second plate bodies, and has a portion and another portion extending respectively into the first and second receiving spaces. The light guide plate is disposed on the reflector unit and is disposed between the first and second side part structures. 
     The bezel includes a surrounding wall disposed to surround the back plate unit, and a press wall connected to a periphery of the surrounding wall. The press wall is disposed to press against the liquid crystal panel for coupling the liquid crystal panel to the backlight module. 
     Preferably, the second edge part of the second plate body is formed with a recessed surface, and the second edge part of the first plate body overlaps the recessed surface. 
     Preferably, the second edge part of the first plate body is formed with a plurality of first fastener holes, and the second edge part of the second plate body is formed with a plurality of second fastener holes corresponding to the first fastener holes. The backlight module further includes a plurality of fasteners passing through the first and second fastener holes and fastening together the first and second plate bodies. 
     Preferably, the portion of the reflector unit that extends into the first receiving space is disposed between the first side part structure and the first light source, and the portion of the reflector unit that extends into the second receiving space is disposed between the second side part structure and the second light source. 
     Preferably, the first plate body further has opposite third and fourth edge parts that extend between the first and second edge parts of the first plate body. The first back plate further has a pair of first side wall structures, each connected to a respective one of the third and fourth edge parts of the first plate body. Similarly, the second plate body further has opposite third and fourth edge parts that extend between the first and second edge parts of the second plate body. The second back plate further has a pair of second side wall structures, each connected to a respective one of the third and fourth edge parts of the second plate body. 
     Preferably, the first plate body has one side that confronts the light guide plate and that is formed with a first groove adjacent to the first side part structure. The second plate body has one side that confronts the light guide plate and that is formed with a second groove adjacent to the second side part structure. 
     Preferably, the first plate body has one side that is opposite to the light guide plate and that is formed with a plurality of first protrusions adjacent to the first side part structure. The second plate body has one side that is opposite to the light guide plate and that is formed with a plurality of second protrusions adjacent to the second side part structure. 
     Preferably, the first and second light sources are one of lamp tubes and light-emitting diode modules. 
     Preferably, the backlight module further includes an optical film that is disposed on the light guide plate. 
     Preferably, the liquid crystal display device further includes a spacer unit that is disposed between the backlight module and the liquid crystal panel, thereby separating the liquid crystal panel from the backlight module. 
     Another object of the present invention is to provide a backlight module that can be assembled with relative ease. 
     A method of assembling a backlight module of a liquid crystal display device according to this invention includes the steps of: 
     A) disposing the reflector unit on the first plate body and the second plate body; 
     B) disposing the light guide plate on the reflector unit; and 
     C) interconnecting the first plate body and the second plate body in a manner that the first receiving space and the second receiving space open toward each other, that the portions of the reflector unit respectively extend into the first and second receiving spaces, and that the light guide plate is disposed between the first and second side part structures. 
     Preferably, when the first and second light sources are lamp tubes, the method of assembling a backlight module further includes, before step A), the step of: 
     D) disposing each of the first and second light sources at a respective one of the portions of the reflector unit such that each of the first and second light sources is disposed in a respective one of the first and second receiving spaces when the first and second plate bodies are interconnected in step C). 
     Preferably, when the first and second light sources are light-emitting diode modules, the method of assembling a backlight module further includes, before step A), the step of: 
     D′) disposing each of the first and second light sources in a respective one of the first and second receiving spaces. 
     Preferably, step A) is conducted before step B), and step C) is conducted after step B). 
     Preferably, in step A), the reflector unit is disposed on the first plate body and the second plate body, with the second edge parts of the first and second plate bodies spaced apart from each other. 
     Preferably, in step C), the second edge parts of the first and second plate bodies are brought to overlap each other and are coupled together with the use of fasteners. 
     Preferably, the method of assembling a backlight module further includes, after step C), a step of: 
     E) disposing the optical film on the light guide plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which; 
         FIG. 1  is an exploded perspective view illustrating a conventional liquid crystal display device; 
         FIG. 2  is an exploded perspective view illustrating a liquid crystal display device of a first preferred embodiment of the present invention; 
         FIG. 3  is an exploded perspective view illustrating a backlight module of the liquid crystal display device of  FIG. 2 ; 
         FIG. 4  is a flowchart illustrating an assembly procedure of the backlight module of  FIG. 3 ; 
         FIG. 5  are cross-sectional schematic views showing the assembly procedure of the backlight module of FIG.  3 ; 
         FIG. 6  are partly cross-sectional schematic views showing the assembly procedure of a modified backlight module having light-emitting diode modules as light sources; 
         FIG. 7  is a partly cross-sectional schematic view along the direction of first side wall structures and second side wall structures to illustrate the structure of the liquid crystal display device of  FIG. 2 ; 
         FIG. 8  is a partly cross-sectional schematic view along the direction of a first side part structure to illustrate the structure of the liquid crystal display device of  FIG. 2 ; 
         FIG. 9  is a partly cross-sectional schematic view along the direction of a second side part structure to illustrate the structure of the liquid crystal display device of  FIG. 2 ; 
         FIG. 10  is a partly cross-sectional schematic view along the direction of the first side part structure to illustrate the structure of a first modification of a spacer unit; 
         FIG. 11  is a partly cross-sectional schematic view along the direction of the second side part structure to illustrate the structure of the first modification of the spacer unit; 
         FIG. 12  is a partly cross-sectional schematic view along the direction of the first and second side wall structures to illustrate the structures of a second modification and a third modification of the spacer unit; 
         FIG. 13  is a partly cross-sectional schematic view along the direction of the first side part structure to illustrate the structure of the second modification of the spacer unit; 
         FIG. 14  is a partly cross-sectional schematic view along the direction of the second side part structure to illustrate the structure of the second modification of the spacer unit; 
         FIG. 15  is a partly cross-sectional schematic view along the direction of the first side part structure to illustrate the structure of the third modification of the spacer unit; 
         FIG. 16  is a partly cross-sectional schematic view along the direction of the second side part structure to illustrate the structure of the third modification of the spacer unit; 
         FIG. 17  is a partly cross-sectional schematic view along the direction of the first and second side wall structures to illustrate the structure of a liquid crystal display device of a second embodiment of the present invention; 
         FIG. 18  is a flowchart illustrating an assembly procedure of a backlight module of the liquid crystal display device of  FIG. 17 ; 
         FIG. 19  are cross-sectional schematic views showing the assembly procedure of the backlight module of  FIG. 18 ; 
         FIG. 20  are partly cross-sectional schematic views showing the assembly procedure of a modified backlight module having light-emitting diode modules as light sources; 
         FIG. 21  is a cross-sectional schematic view showing a first groove of a first back plate and a second groove of a second back plate of another modified backlight module; 
         FIG. 22  is a cross-sectional schematic view showing a first protrusion of a first back plate and a second protrusion of a second back plate of yet another modified backlight module; and 
         FIG. 23  is a cross-sectional schematic view showing first and second protrusions on first and second back plates of still another modified backlight module. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Before the present invention is described in greater detail with reference to the preferred embodiments, it should be noted that the same reference numerals are used to denote the same elements throughout the following description. 
     Referring to  FIG. 2 , in a first preferred embodiment of a liquid crystal display (LCD) device  20  according to the present invention, the LCD device  201  includes a backlight module  21 , a liquid crystal panel  22 , a circuit board  23 , a spacer unit  24 , and a bezel  25 . The spacer unit  24  is disposed between the liquid crystal panel  22  and the backlight module  21  for separating the liquid crystal panel  22  from the backlight module  21  by a distance, and the liquid crystal panel  22  is fixed on the backlight module  21  by the bezel  25 . The circuit board  23  is connected to the liquid crystal panel  22 . 
     Referring to  FIGS. 3 and 5 , the backlight module  21  includes a back plate unit  3 , a reflector unit  4 , a light guide plate  51 , an optical film  52 , a first light source  61 , and a second light source  62 . The reflector unit  4  is disposed on the back plate unit  3 , and the light guide plate  51  and the optical film  52  are stacked on the reflector unit  4  in sequence. The first light source  61  and the second light source  62  are disposed adjacent to opposite sides of the light guide plate  51 , respectively, and are received in the back plate unit  3 . 
     The back plate unit  3  includes a first back plate  31  and a second back plate  32 . The first back plate  31  includes a rectangular first plate body  311 . The first plate body  311  has opposite first and second edge parts, and a first side part structure  312  is connected to the first edge part of the first plate body  311 . The second edge part of the first plate body  311  is formed with a first recessed surface  310  on a rear side of the first plate body  311 , and a plurality of first fastener holes  315  are formed in the second edge part of the first plate body  311 . The first plate body  311  further has opposite third and fourth edge parts that extend between the first and second edge parts of the first plate body  311 , and each of a pair of first side wall structures  314  is connected to a respective one of the third and fourth edge parts of the first plate body  311 . The first side part structure  312  includes a first surrounding wall  312   b  extending transversely from a front surface of the first plate body  311 , a first end wall  312   c  extending from a distal end of the first surrounding wall  312   b  at an angle toward the second edge part of the first plate body  311  and spaced apart from the first plate body  311 , and a pair of first side walls  312   a,  each extending from a respective one of two ends of the first surrounding wall  312   b  at an angle toward a respective one of the first side wall structures  314 . The first surrounding wall  312   b,  the first end wall  312   c  and the first side walls  312   a  cooperate to define a first receiving space  313 . In this embodiment, the first side part structure  312 , the first side wall structures  319  and the first plate body  311  are formed integrally. 
     The second back plate  32  includes a rectangular second plate body  321 . The second plate body  321  has opposite first and second edge parts, and a second side part structure  322  is connected to the first edge part of the second plate body  321 . The second edge part of the second plate body  321  is formed with a second recessed surface  320  on a front side of the second plate body  321 , and a plurality of second fastener holes  325  are formed in the second edge part of the second plate body  321 . The second plate body  321  further has opposite third and fourth edge parts that extend between the first and second edge parts of the second plate body  321 , and each of a pair of second side wall structures  324  is connected to a respective one of the third and fourth edge parts of the second plate body  321 . The second side part structure  322  includes a second surrounding wall  322   b  extending transversely from a front surface of the second plate body  321 , a second end wall  322   c  extending from a distal end of the second surrounding wall  322   b  at an angle toward the second edge part of the second plate body  321  and spaced apart from the second plate body  321 , and a pair of second side walls  322   a,  each extending from a respective one of two ends of the second surrounding wall  322   b  at an angle toward a respective one of the second side wall structures  329 . The second surrounding wall  322   b,  the second end wall  322   c  and the second side walls  322   a  cooperate to define a second receiving space  323 . In this embodiment, the second side part structure  322 , the second side wall structures  324  and the second plate body  321  are formed integrally. 
     The first plate body  311  and the second plate body  321  are interconnected with the second edge part of the first plate body  311  overlapping the second edge part of the second plate body  321  so as to form a receiving plane. The receiving plane, the first side part structure  312 , the second side part structure  322 , the first side wall structures  314 , and the second side wall structures  324  cooperate to define an accommodating space. 
     The reflector unit  4  is disposed on the receiving plane formed by the first and second plate bodies  311 ,  321 , and the reflector unit  4  has an end portion extending into the first receiving space  313  and an opposite end portion extending into the second receiving space  323 . In this embodiment, the end portion and the opposite end portion of the reflector unit  4  are substantially C-shaped to match the first and second side part structures  312 ,  322 . The reflector unit  4  has a light-reflecting function and can serve as a lampshade. Referring to  FIG. 3 , the reflector unit  4  may be a reflective plate or a reflective material coated on the inner wall faces of the first and second side part structures  312 ,  322 . 
     The light guide plate  51  is disposed on the reflector unit  4  and between the first side part structure  312  and the second side part structure  322 . The optical film  52  is disposed on the light guide plate  51 . The optical film  52  can be a brightness enhancing film, a prism sheet, a diffuser sheet, etc. One or more optical films  52  may be disposed on the light guide plate  51 . It is noted that the optical film  52  is optional and may be omitted in some embodiments of the invention. 
     The first light source  61  is received in the first receiving space  313  and is adjacent to an end portion of the light guide plate  51 . The second light source  62  is received in the second receiving space  323  and is adjacent to an opposite end portion of the light guide plate  51 . In this embodiment, the first and second light sources  61 ,  62  are cold cathode fluorescent lamps. 
     Referring to  FIG. 4  and  FIG. 5 , a method of assembling the backlight module  21  of the first preferred embodiment includes the steps of: 
       900 ) disposing the first and second light sources  61 ,  62  respectively adjacent to one of the end portion and the opposite end portion of the reflector unit  4 . The end portions of the reflector unit  4  are bent to be substantially C-shaped for receiving the first and second light sources  61 ,  62 . 
       902 ) disposing the reflector unit  4  on the first plate body  311  and the second plate body  321 . The first back plate  31  and the second back plate  32  are arranged in a manner that the first receiving space  313  opens toward the second receiving space  323  with the second edge parts of the first and second plate bodies  31 ,  32  spaced apart from each other. 
       904 ) disposing the light guide plate  51  on the reflector unit  4 . 
       906 ) interconnecting the first plate body  311  and the second plate body  321  in a manner that the first receiving space  313  opens toward the second receiving space  323  for receiving the end portion and the opposite end portion of the reflector unit  4  respectively into the first receiving space  313  and the second receiving space  323 . The light guide plate  51  is between the first side part structure  312  and the second side part structure  322  at this time. 
     More specifically, the first recessed surface  310  of the first plate body  311  overlaps the second recessed surface  320  of the second plate body  321 , i.e., the second edge part of the first plate body  311  overlaps the second edge part of the second plate body  321 . Screw fasteners  7  pass through the first fastener holes  315  and the second fastener holes  325  so as to fasten together the first back plate  31  and the second back plate  32 . The fastening mechanism between the first and second back plates  31 ,  32  is not limited in this preferred embodiment, and a locking device or other connecting structures may be employed instead of the first recessed surface  310  and the second recessed surface  320 . 
     Moreover, the first and second light sources  61 ,  62  have been disposed adjacent to a respective one of the end portion and the opposite end portion of the reflector unit  4 . Thus, the first, and second light sources  61 ,  62  are received in the respective one of the first and second receiving spaces  313 ,  323  when the first back plate  31  is connected to the second back plate  32 . 
       908 ) disposing the optical film  52  on the light guide plate  51 . Because the optical film  52  is flexible, it can be flexed for fitting in the accommodating space. 
     Furthermore, referring to  FIG. 6 , the first light source  61  and the second light source  62  may be light-emitting diode (LED) modules in other embodiments of the invention. Each of the LED modules has a LED component  63  and a circuit base  64 . When LED modules are used, a step  900 ′) may be used instead of step  900 ) in the method of assembling the backlight module  21 , with the other steps unchanged. 
       900 ′) disposing the first light source  61  and the second light source  62  respectively in the first receiving space  313  and the second receiving space  323 . More specifically, each circuit base  64  is mounted on a respective one of the inner wall faces of the first surrounding wall  312   b  of the first side part structure  312  and the second surrounding wall  322   b  of the second side part structure  322  by means of heat conductive glue. Thus, the heat generated by the LED components  63  may be dissipated effectively through the first back plate  31  and the second back plate  32 . Because the circuit bases  64  are mounted on the inner wall faces of the first and second surrounding walls  312   b,    322   b,  the reflector unit  4  has a planar shape in  FIG. 6 . Preferably, in step  902 ), a pair of reflector components  41  with small dimensions are mounted on the inner wall faces of the first end wall  312   c  and the second end wall  322   c  for enhancing the reflecting effect. 
     Referring to  FIG. 7 ,  FIG. 8  and  FIG. 9 , the spacer unit  24  is disposed on the backlight module  21 . The spacer unit  24  includes a first support flange  811  extending from the first side part structure  312 , a pair of first liners  812  each extending from a respective one of the first side wall structures  314 , a second support flange  821  extending from the second side part structure  322 , and a pair of second liners  822  each extending from a respective one of the second side wall structures  324 . The first support flange  811  and the first liners  812  are formed integrally with the first back plate  31 . The second support flange  821  and the second liners  822  are formed integrally with the second back plate  32 . 
     The liquid crystal panel  22  is disposed on the first support flange  811 , the second support flange  821 , the first liners  812  and the second liners  822 , and is thus separated from the backlight module  21 . In this way, the liquid crystal panel  22  will not be scratched or damaged due to contact with the backlight module  21 . 
     In this embodiment, the spacer unit  24  may have other configurations for spacing the liquid crystal panel  22  apart from the backlight module  21 . Referring to FIG.  7 ,  FIG. 10  and  FIG. 11  according to a first modification of the spacer unit  24 , each of a pair of first liners  831  is disposed between the light guide plate  51  and a respective one of the first side wall structures  314 , and each of a pair of second liners  832  is disposed between the light guide plate  51  and a respective one of the second side wall structures  324 . The spacer unit  24  further includes a first support flange  811  extending from the first side part structure  312 , and a second support flange  821  extending from the second side part structure  322 . The structures of the first and second support flanges  811 ,  812  are the same as those mentioned above. Each of the first and second liners  831 ,  832  has a portions extending over the optical film  52 . In this way, the liquid crystal panel  22  is disposed on the extending portion of the first and second liners  831 ,  832 , the first support flange  811  and the second support flange  821 . 
     Referring to  FIG. 12 ,  FIG. 13  and  FIG. 14 , according to a second modification of the spacer unit  24 , each of a pair of first spacer strips  841  is disposed on a respective one of the first support flange  811  and the second support flange  821 , each of four second spacer strips  841 ′ is disposed on the extending portion of a respective one of the first and second liners  831 ,  832 . In this way, the liquid crystal panel  22  is disposed on the first spacer strips  841  and the second spacer strips  841 ′, and is spaced farther apart from the backlight module  21  compared to the first modification of the spacer unit  24 . 
     Referring to  FIG. 12 ,  FIG. 15  and  FIG. 16 , according to a third modification of the spacer unit  24 , a first support flange  811  extends from the first side part structure  312 , a second support flange  821  extending from the second side part structure  322 , each of a pair of first spacer strips  841  is disposed on a respective one of the first and second support flanges  811 ,  821 , and each of four second spacer strips  842  is disposed on the optical film  52 . The second spacer strips  892  are used to replace the first and second liners  831 ,  832  and the second spacer strips  841 ′ in the second modification of the spacer unit  24 . In this way, the liquid crystal panel  22  is disposed on the first spacer strips  841  and the second spacer strips  842 . 
     The structure of the spacer unit  24  described above are non-limiting examples of the present invention. Those skilled in the art may readily appreciate other suitable forms of the spacer unit  24  for spacing the liquid crystal panel  22  apart from the backlight module  21 . 
     Referring again to  FIG. 7 , the circuit board  23  is connected to the liquid crystal panel  22  through a flexible cable  85 . The circuit board  23  is disposed on the rear side of the second plate body  321  and adjacent to the second side part structure  322 . The flexible cable  85  is arranged between the bezel  25  and the second side part structure  322  of the second back plate  32 . However, depending on the structure of the liquid crystal panel  22 , the circuit board  32  may be disposed on the rear side of the first plate body  311  and adjacent to the first side part structure  312 , and the flexible cable  85  may be arranged between the bezel  25  and the first side part structure  312  of the first back plate  31 . 
     The bezel  25  includes a surrounding wall  253  and a press wall  251  connected to a periphery of the surrounding wall  253  and defining an opening  252  for exposing the liquid crystal panel  22 . The bezel  25  couples the liquid crystal panel  22  to the backlight module  21  in a manner that the surrounding wall  253  surrounds the back plate unit  3 , and the press wall  251  presses against the liquid crystal panel  22  so that the entire structure of the LCD device  201  is made stronger. 
     Referring to  FIG. 17 , a second preferred embodiment of the LCD device  202  of the present invention includes a backlight module  21 ′, a liquid crystal panel  22 , a circuit board  23 , a spacer unit  24 , and a bezel  25 . The main difference between the second embodiment and the first embodiment resides in the backlight module  21 ′. The backlight module  21 ′ of the LCD device  202  includes only one light source  61 ′, and the second side part structure  322 ′ of the second back plate  32 ′ only includes a second surrounding wall  322   b ′. Only one end portion of a reflector unit  4 ′ is substantially C-shaped. Furthermore, in order to match the single light source design, the structures of the reflector unit  4 ′, the light guide plate  51 ′, the first back plate  31 ′ and the second back plate  32 ′ are all altered as compared with the first preferred embodiment. Since the alterations may be readily appreciated by those skilled in the art from the drawing, further details of the same are omitted herein for the sake of brevity. The structures and functions of other parts of the LCD device  202  are the same as those of the first preferred embodiment, and a description thereof will not be repeated herein. 
     Referring to  FIG. 18  and  FIG. 19 , a method of assembling the backlight module  21 ′ of the second preferred embodiment includes the steps of: 
       901 ) disposing the first light source  61 ′ adjacent to the end portion of the reflector unit  4 ′. 
       903 ) disposing the reflector unit  4 ′ on the first plate body  311 ′ and the second plate body  312 ′ similar to step  902 ) of the first preferred embodiment. 
       905 ) disposing the light guide plate  51 ′ on the reflector unit  4 ′. 
       907 ) interconnecting the first plate body  311 ′ and the second plate body  321 ′ in a manner that the first receiving space  313 ′ opens toward the second side part structure  322 ′ for receiving the end portion of the reflector unit  4 ′ into the first receiving space  313 ′. The light guide plate  51 ′ is between the first side part structure  312 ′ and the second side part structure  322 ′ at this time. The manner of interconnecting the first back plate  31 ′ and the second back plate  32 ′ is the same as that mentioned in step  906 ) of the method of the first preferred embodiment. 
       909 ) disposing the optical film  52 ′ on the light guide plate  51 ′. 
     Moreover, referring to  FIG. 20 , the first light source  61 ′ may be a LED module. The LED module has a LED component  63 ′ and a circuit base  64 ′. When the LED module is used, a step  901 ′) may be used instead of step  901 ) in the method of assembling the backlight module  21 ′, with the other steps unchanged. 
       901 ′) disposing the first light source  61 ′ in the first receiving space  313 ′. More specifically, the circuit base  64 ′ is mounted on the inner wall face of the first surrounding wall  312   b ′ of the first side part structure  312 ′ by means of heat conductive glue. Thus, the heat generated by the LED component  63 ′ may be dissipated effectively through the first back plate  31 ′. Because the circuit base  64 ′ is mounted on the inner wall face of the first surrounding wall  312   b ′, the reflector unit  4 ′ has a planar shape in  FIG. 20 . Preferably, in step  903 ), a reflector component  41 ′ with small dimensions is mounted on the inner wall face of the first end wall  312   c ′ for enhancing the reflecting effect. 
     Additionally, referring to  FIG. 21 , the first plate body  311 ′ of the first back plate  31 ′ of the backlight module of the LCD device  202  of the present invention 
     May be configured to have one side that confronts the light guide plate  51 ′ (see  FIG. 17 ) and that is formed with a first groove  316  adjacent to the first side part structure  312 ′. The second plate body  321 ′ of the second back plate  32 ′ of the backlight module of the LCD device  202  of the present invention may be configured to have one side that confronts the light guide plate  51 ′ (see  FIG. 17 ) and that is formed with a second groove  326  adjacent to the second side part structure  322 ′. When there are wires or cables (not shown) arranged in the backlight module  21 ′, the wires or the cables may be received in the first groove  316  and the second groove  326 . Thus, containers or other receiving objects attached to the backlight module  21 ′ may be omitted to save cost and space, and the wires or the cables may be prevented from being undesirably pulled or caught. The back plate unit  3  of the LCD device  201  of the first preferred embodiment may be provided with the same design. 
     Furthermore, referring to  FIG. 22  and  FIG. 23 , the first plate body  311 ′ of the first back plate  31 ′ of the backlight module of the LCD device  202  of the present invention may be configured to have one side that is opposite to the light guide plate  51 ′ (see  FIG. 17 ) and that is formed with a plurality of first protrusions  331  adjacent to the first side part structure  312 ′, and the second plate body  321 ′ of the second back plate  32 ′ of the LCD device  202  of the present invention has one side that is opposite to said light guide plate  51 ′ and that is formed with a plurality of second protrusions  332  adjacent to the second side part structure  322 ′. The circuit board  23  (see  FIG. 17 ) and a power source (not shown) may be attached to the first plate body  311 ′ and the second plate body  321 ′ at the first protrusions  331  and the second protrusions  332 , such that additional supports for fixing the circuit board  23  and the power source may be omitted, and the cost of the LCD device  202  may be further reduced. The first and second protrusions  331 ,  332  may be formed through molding or riveting techniques. The back plate unit  3  of the LCD device  201  of the first preferred embodiment may be provided with the same design. 
     In summary, lampshades may be omitted and costs may be reduced by virtue of the design of the back plate units  3 ,  3 ′ and the structures of the first side part structures  312 ,  312 ′, the second side part structures  322 ,  322 ′ and the reflector units  4 ,  4 ′ of the backlight modules  21 ,  21 ′ of the LCD devices  201 ,  202  of the present invention. In assembling the backlight modules  21 ,  21 ′, the reflector units  4 ,  4 ′, the light guide plates  51 ,  51 ′, the first light sources  61 ,  61 ′, and the second light source  62  are disposed and assembled more conveniently since the first back plate  31 ,  31 ′ and the second back plate  32 ,  32 ′ are initially arranged apart from each other. Thus, time and manpower for assembling the backlight modules  21 ,  21 ′ can be saved and costs maybe reduced. Besides, by providing the first grooves  316 , the second grooves  326 , the first protrusions  331  and the second protrusions  332 , costs may be further reduced. 
     While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.