Abstract:
An exemplary backlight module ( 20 ) includes a back frame ( 25 ) including a bottom plate ( 251 ) and light sources ( 24 ) each including a base ( 241 ). The bottom plate includes fixing structures ( 254 ) that are configured for fixing the light sources to the bottom plate such that the bases of the light sources contact the bottom plate. A liquid crystal display device ( 2 ) using the backlight module is also provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is related to, and claims the benefit of, a foreign priority application filed in China as Serial No. 200720121063.8 on Jun. 22, 2007. The related application is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a backlight module that has a fixing structure and a liquid crystal display (LCD) device implementing the backlight module. 
     BACKGROUND 
     LCD devices are commonly used as displays for compact electronic apparatuses, because they provide good quality images with little power consumption and are very thin. The liquid crystal material in an LCD device does not emit light. The liquid crystal material must be lit by a light source to clearly and sharply display text and images. Thus, a backlight module is generally needed for an LCD device. 
     Referring to  FIG. 13 , a typical LCD device  1  includes a display panel  19  and a backlight module  10  opposite to the display panel  19 . The backlight module  10  is a direct type backlight module, and includes a metal back frame  15 , a plurality of light sources  14 , a diffuser  11 , and a brightness enhancement film (BEF)  12 . The plurality of light sources  14 , the diffuser  11 , and the BEF  12  are accommodated in the metal back frame  15  in that order from bottom to top. 
     Each light source  14  is a light bar, which includes a base  141  and a plurality of light emitting elements  142  disposed on the base  141 . Some circuits (not shown) disposed on the base  141  are used for electrically connecting an external power supply (not shown) to the light emitting elements  142 . The external power supply provides power to the light emitting elements  142 , enabling the light emitting elements  142  to emit light beams. The light beams emitted from the light emitting elements  142  are provided to the display panel  19  via the diffuser  11  and the BEF  12 . 
     The metal back frame  15  includes a bottom plate  151  and side walls  150  extending perpendicularly from the edges of the bottom plate  151 . The bottom plate  151  and the side walls  150  define an accommodating space (not labeled). The plurality of light sources  14 , the diffuser  11 , and the BEF  12  are received in the accommodating space. 
     When the backlight module  10  is assembled, the light sources  14  are placed on the bottom plate  151  of the back frame  15  and arranged in an array. Two ends (not labeled) of each light source  14  are affixed to the bottom plate  151  using screws (not labeled). An additional screw (not labeled) can be used to fasten the middle part (not labeled) of the light source  14  to the bottom plate  151 . 
     Thus, the backlight module  10  needs plural screws to affix the light sources  14  to the bottom plate  151  of the back frame  15 . The larger the size of the backlight module  10 , the more screws that will be needed. Screws make assembling and disassembling the light sources  14  unduly inconvenient and inefficient. Furthermore, the base  141  of the light source  14  needs to be thin for better thermal conductivity. But the base  141  is liable to warp and lose contact with the bottom plate  151  if it is too thin. Thus conduction of heat away from the light source  14  decreases when the base  141  becomes thinner. 
     Therefore, an improved backlight module is desired to overcome the above-described deficiencies. 
     SUMMARY 
     An aspect of the invention relates to a backlight module including a back frame including a bottom plate and a plurality of light sources each including a base. The bottom plate includes a plurality of fixing structures that are configured for fixing the light sources to the bottom plate such that the bases of the light sources contact the bottom plate. 
     Other novel features and advantages will become more apparent from the following detailed description and when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of at least one embodiment of the present invention. In the drawings, like reference numerals designate corresponding parts throughout the various views. 
         FIG. 1  is an exploded, isometric view of an LCD device according to a first embodiment of the present invention. 
         FIG. 2  is an enlarged view of a circled portion II of  FIG. 1 . 
         FIG. 3  is an exploded, isometric view of a backlight module of an LCD device according to a second embodiment of the present invention. 
         FIG. 4  is an enlarged view of a circled portion IV of  FIG. 3 . 
         FIG. 5  is an exploded, isometric view of a backlight module of an LCD device according to a third embodiment of the present invention. 
         FIG. 6  is an exploded, isometric view of a backlight module of an LCD device according to a fourth embodiment of the present invention. 
         FIG. 7  is an enlarged view of a circled portion VII of  FIG. 6 . 
         FIG. 8  is an exploded, isometric view of a backlight module of an LCD device according to a fifth embodiment of the present invention. 
         FIG. 9  is an enlarged view of a circled portion IX of  FIG. 8 . 
         FIG. 10  is an exploded, isometric view of a backlight module of an LCD device according to a sixth embodiment of the present invention. 
         FIG. 11  is an inverted view of the backlight module of  FIG. 10  when assembled. 
         FIG. 12  is an enlarged view of a circled portion XII of  FIG. 11 . 
         FIG. 13  is an exploded, isometric view of a conventional LCD device. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Reference will now be made to the drawings to describe preferred embodiments of the present invention in detail. 
     Referring to  FIG. 1 , an LCD device  2  according to a first embodiment of the present invention is shown. The LCD device  2  includes a display panel  29  and a backlight module  20  opposite to the display panel  29 . The backlight module  20  is a direct type backlight module, and includes a metal back frame  25 , a plurality of light sources  24 , a diffuser  21 , and a BEF  22 . The plurality of light sources  24 , the diffuser  21 , and the BEF  22  are accommodated in the metal back frame  25  in that order from bottom to top. 
     Each light source  24  is a light bar, and includes a base  241  and a plurality of light emitting elements  242  disposed on the base  241 . Some circuits (not shown) disposed on the base  241  are used for electrically connecting an external power (not shown) to the light emitting elements  242 . The external power supply provides power to the light emitting elements  242 , enabling the light emitting elements  242  to emit light beams. 
     The metal back frame  25  includes a bottom plate  251  and side walls  250  extending perpendicularly from the edges of the bottom plate  251 . The bottom plate  251  and the side walls  250  define an accommodating space (not labeled). The plurality of light sources  24 , the diffuser  21 , and the BEF  22  are received in the accommodating space. A plurality of protuberant strips  252  is arranged on the bottom plate  251  in an array. Each protuberant strip  252  has the same shape as the base  241  of the light source  24  and matches to a corresponding light source  24 . An upper surface of each protuberant strip  252  is a bandy surface. 
     Referring also to  FIG. 2 , two fixture portions  254  are disposed on the bottom plate  251  and at two ends (not labeled) of each protuberant strip  252 . Each fixture portion  254  includes a groove (not labeled) for receiving the corresponding end of the base  241 . 
     The distance between the two fixture portions  254  is slightly less than the length of the base  241  of the light source  24 , causing the base  241  to bow slightly and match with the corresponding protuberant strip  252  when the two ends of the base  241  of each light source  24  are inserted into the grooves of the corresponding fixture portions  254 . Then the light source  24  becomes fixed on the bottom plate  251  of the metal back frame  25 . The light source  24  can be detached from the bottom plate  251  by removing the ends of the base  241  from the grooves of the corresponding fixture portions  254 . 
     In summary, the light sources  24  are fixed on the bottom plate  251  of the metal back frame  25  with the bases  241  held in contact with the bandy surfaces of the protuberant strips  252  by inserting the ends of the bases  241  into the grooves of the fixture portions  254 . Assembling the light sources  24  does not require external fasteners such as screws, making assembling and disassembling the light sources  24  convenient and efficient. Furthermore, the base  241  is forced into contact with the bandy cambered surface of the corresponding protuberant strip  252 , increasing thermal conductivity and making it difficult for the base  241  to warp. 
     In an alternative embodiment, the plurality of light sources  24  disposed on the bottom plate  251  is not limited to an array having two columns according to the above-described embodiment. For example, the number of the columns of the array can vary according to needs. Furthermore, a screw (not labeled) can be added to affix the middle part of each light source  24  for added security. 
     Referring now to  FIG. 3  and  FIG. 4 , aspects of a backlight module  30  according to a second embodiment of the present invention are shown. Two first openings  343  are disposed near an end (not labeled) of a base  341  of each light source  34  at two opposite longer edges (not labeled) of the base  341 . The two first openings  343  each have the shape of a circular arc. A second opening  344  with a rectangular (e.g., square) shape is disposed near an opposite end (not labeled) of the base  341 . A metal back frame  35  includes a bottom plate  351  and two opposite side flanges (not labeled). For each light source  34 , two first fixture blocks  353  corresponding to the two first openings  343  are disposed on the bottom plate  351 . A second fixture block  354  corresponding to the second opening  344  is also disposed on the bottom plate  351 . The second fixture block  354  has a substantially L-shaped cross-section, and can be formed by punching the bottom plate  351 . The second fixture block  354  includes a supporting portion (not labeled) and a buckling portion (not labeled). The supporting portion is connected to the bottom plate  351 , and an extending direction of the buckling portion is in a direction away from the first fixture blocks  353 . In the illustrated embodiment, an angle between the supporting portion and the buckling portion is less than 90°. 
     The backlight module  30  is assembled by attaching the light sources  34  one by one. Each light source  34  is maneuvered so that the corresponding second fixture block  354  is received through the second opening  344 . Then the base  341  slid toward the first fixture blocks  353  and is affixed to the bottom plate  351  by buckling the neck between the first openings  343  and the first fixture blocks  353 . Thus the base  341  fully abuts the bottom plate  351  and can contact the bottom plate  351  along a length thereof. 
     Referring to  FIG. 5  this shows a backlight module  40  according to a third embodiment of the present invention. The backlight module  40  is similar to the backlight module  30  in  FIG. 3 . However, two openings  443  are disposed near opposite ends (not labeled) of a base  441  of each light source  44  at two opposite longer edges (not labeled) of the base  441 . Two fixture blocks  453  corresponding to the two openings  443  are disposed on a bottom plate  451  of a metal back frame  45 . The fixture blocks  453  each have a substantially L-shaped cross-section, and can be formed by punching the bottom plate  451 . The two fixture blocks  453  each include a supporting portion (not labeled) and a buckling portion (not labeled). The supporting portions are connected to the bottom plate  451 , and extending directions of the buckling portions are in opposite directions. In the illustrated embodiment, the angle between the supporting portion and the buckling portion of each fixture block  453  is less than 90°. 
     The backlight module  40  is assembled by attaching the light sources  44  one by one. The base  441  of each light source  44  is placed on the bottom plate  451  with the two openings  443  facing the two corresponding fixture blocks  453 . Next, the base  441  is rotated until the ends of the base  441  at the openings  443  buckle to the fixture blocks  453  of the bottom plate  451 . 
     Referring to  FIG. 6  and  FIG. 7  aspects of a backlight module  50  according to a fourth embodiment of the present invention are shown. The backlight module  50  is similar to the backlight module  40  in  FIG. 5 . However, two openings  543  are disposed near two ends (not labeled) of a base  541  of each light source  54 . The two openings  543  each have a rectangular (e.g., square) shape. Two fixture blocks  553  corresponding to the two openings  543  are disposed on a bottom plate  551  of a metal back frame  55 . The fixture blocks  553  can be formed by punching the bottom plate  551  and creating angles with the bottom plate  551 . The extending directions of the two fixture blocks  553  are toward each other. In the illustrated embodiment, the fixture blocks  553  are gently curved or arced. The angle between each fixture block  553  and the bottom plate  551  is less than 90°. 
     The backlight module  50  is assembled by attaching the light sources  54  one by one. The base  541  of each light source  54  is slightly bent until the corresponding fixture blocks  553  of the bottom plate  551  are inserted into the openings  543  and buckle the base  541  at the openings  543  when the base  541  rebounds. Thus the base  541  abuts the bottom plate  551 , and the light source  54  is fixed to the bottom plate  551 . 
     Referring to  FIG. 8  and  FIG. 9 , aspects of a backlight module  60  according to a fifth embodiment of the present invention are shown. The backlight module  60  is similar to the backlight module  50  in  FIG. 6 . However, fixture blocks  653  are disposed on a bottom plate  651  of a metal back frame  65 . Each fixture block  653  includes a supporting portion  654 , a connection portion  655 , and a buckling portion  656  that are connected. The supporting portion  654  is connected to the bottom plate  651 . The buckling portion  656  includes a downwardly curved part (not labeled). Typically, the buckling portion  656  is resiliently deformable. The fixture blocks  653  are arranged in pairs, with the fixture blocks  653  in each pair pointing in the same direction. The two fixture blocks  653  correspond to two openings  643  of a base  641  of a respective light source  64 . 
     The backlight module  60  is assembled by attaching the light sources  64  one by one. Each pair of fixture blocks  653  are inserted into the two openings  643  of the base  641  of the corresponding light source  64 . Then the base  641  is moved along the opposite direction to the pointing direction of the fixture blocks  653  until the buckling portions  656  press against the base  641 . Thus, the base  641  abuts the bottom plate  651 , and the light source  64  is fixed to the bottom plate  651 . 
     Referring to  FIGS. 10-12 , aspects of a backlight module  70  according to a sixth embodiment of the present invention are shown. The backlight module  70  is similar to the backlight module  20  in  FIG. 1 . However, a bottom plate  751  of a metal back frame  75  of the backlight module  70  includes a plurality of recesses  752 . The recesses  752  are stripe shaped and can be formed by punching the bottom plate  751 . The number of the recesses  752  matches the number of light sources  74  and the size and shape of each recess  752  match the corresponding light source  74 . Each recess  752  includes four side walls (not labeled). Two through holes (not labeled) are disposed on the two side walls at opposite ends (not labeled) of the recess  752 . A fixture block  753  is disposed at the center part of one of the two longer opposite side walls of the recess  752 . An opening  743  corresponding to the fixture block  753  is disposed on a base  741  of the corresponding light source  74 . The base  741  is longer than the recess  752 . 
     The backlight module  70  is assembled by attaching the light sources  74  one by one. The base  741  of each light source  74  is slightly bent until the two ends of the base  741  are inserted into the two through holes disposed on the two side walls at the two opposite ends (not labeled) of the recess  752 . Then the base  741  rebounds and abuts the bottom plate  751 , with the fixture block  753  fitting into the opening  743  thereby fixing the base  741  on the bottom plate  751 . 
     It is to be understood that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes made in detail, especially in matters of shape, size, and arrangement of parts, within the principles of the invention, to the full extent indicated by the broad general meaning of the terms in which appended claims are expressed.