Abstract:
An exemplary backlight module ( 2 ) includes a light guide plate ( 21 ) and a light source ( 23 ). The light guide plate includes a main body, a protrusion ( 217 ) extending from an end of the main body, a main light emitting surface ( 211 ), and a light incident surface ( 215 ) at the end of the main body. Wherein one side of the protrusion forms a part of the light emitting surface, another side ( 2171 ) of the protrusion is adjacent to the light incident surface. The protrusion and the light incident surface cooperatively form an accommodating space. The light source is substantially received in the accommodating space.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to backlight modules and liquid crystal display (LCD) devices; and particularly to a backlight module with a light guide plate having a protrusion, and an LCD device using the backlight module. 
       BACKGROUND 
       [0002]    LCD devices are commonly used as display devices for compact electronic apparatuses. This is because LCD devices not only provide good quality images, but also are very thin and consume little power. The liquid crystal in a liquid crystal display device is not capable of emitting light by itself. The liquid crystal has to be lit by a light source so as to clearly and sharply display text and images. Thus, a backlight module for an LCD is generally needed. 
         [0003]      FIG. 9  is an exploded, isometric view of a typical backlight module. The backlight module  1  includes a light guide plate (LGP)  11 , a light source  13 , and a set of optical films  15  disposed on the LGP  11 . The LGP  11  includes a top light emitting surface  111 , a bottom surface  113 , and a side light incident surface  115 . The light source  13  is located adjacent to the light incident surface  115 . The light source  13  includes a cold cathode fluorescence lamp (CCFL)  131 , a U-shaped reflector  133  partially enclosing the CCFL  131 , and two rubber blocks  135  engaged with two ends of the CCFL  131  respectively. 
         [0004]    In  FIG. 10 , an exploded, side view of the backlight module  1  is shown. The two parallel sidewalls of the U-shaped reflector  133  are engaged with end portions of the light emitting surface  111  and the bottom surface  113  respectively, in order to hold the U-shaped reflector  133  in place at an end of the LGP  11 . The two rubber blocks  135  are fittingly engaged in two ends of the U-shaped reflector  133 , and contact the light incident surface  115  of the LGP  11 . 
         [0005]    If the LGP  11  sustains shock or undergoes vibration, only the two rubber blocks  135  absorb mechanical force that transmits from the LGP  11  to the CCFL  131 . Thus, when the backlight module  1  experiences shock, the CCFL  131  is liable to be damaged. In addition, if the U-shaped reflector  133  becomes distorted, light beams emitted by the CCFL  131  may leak out from the backlight module  1 . This leads to a decrease in the light utilization efficiency of the backlight module  1 . Furthermore, because the set of optical films  15  is close to the light source  13 , during operation of the light source  13  the surrounding temperature of the light source  13  rises. This may result in the set of optical films  15  becoming too hot and distorting. 
         [0006]    What is needed is a backlight module and an LCD device with the backlight module which can overcome the above-described deficiencies. 
       SUMMARY 
       [0007]    An exemplary backlight module includes a light guide plate and a light source. The light guide plate includes a main body, a protrusion extending from an end of the main body, a main light emitting surface, and an light incident surface at the end of the main body. Wherein one side of the protrusion forms a part of the light emitting surface, another side of the protrusion is adjacent to the light incident surface, and the protrusion and the light incident surface cooperatively form an accommodating space. The light source is substantially received in the accommodating space. 
         [0008]    Another exemplary A backlight module includes a light guide plate, and a light source. Wherein an end of the light guide plate defines a channel which is bounded by two sides of the light guide plate. The light source is substantially accommodated in the channel, and light beams from the light source enter the light guide plate through one of said two sides. 
         [0009]    An exemplary LCD device includes a liquid crystal display panel and a backlight module for providing light beams to illuminate the liquid crystal display panel. The backlight module includes a light guide plate and a light source. The light guide plate includes a main body, a protrusion extending from an end of the main body, a main light emitting surface, and a light incident surface at the end of the main body. Wherein one side of the protrusion forms a part of the light emitting surface, another side of the protrusion is adjacent to the light incident surface, and the protrusion and the light incident surface cooperatively form an accommodating space. The light source is substantially received in the accommodating space. 
         [0010]    Other novel features and advantages will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, all the views are schematic. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an exploded, isometric view of a backlight module according to a first embodiment of the present invention. 
           [0012]      FIG. 2  is an exploded, side view of the backlight module of  FIG. 1 . 
           [0013]      FIG. 3  is an enlarged view of a circled portion III of  FIG. 2 . 
           [0014]      FIG. 4  is an exploded, side view of a liquid crystal display device, which has the backlight module of  FIG. 1  installed therein. 
           [0015]      FIG. 5  is an exploded, side view of a backlight module according to a second embodiment of the present invention. 
           [0016]      FIG. 6  is an exploded, side view of a backlight module according to a third embodiment of the present invention. 
           [0017]      FIG. 7  is an enlarged view of a circled portion VII of  FIG. 6 . 
           [0018]      FIG. 8  is an exploded, side view of a backlight module according to a fourth embodiment of the present invention. 
           [0019]      FIG. 9  is an exploded, isometric view of a conventional backlight module. 
           [0020]      FIG. 10  is an exploded, side view of the backlight module of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0021]    Referring to  FIG. 1 , an exploded, isometric view of a backlight module  2  according to a first embodiment of the present invention is shown. The backlight module  2  includes an LGP  21 , a light source  23  adjacent to the LGP  21 , and a set of optical films  25  disposed on the LGP  21 . 
         [0022]    Also referring to  FIG. 2 , the LGP  21  includes a light emitting surface  211 , and a bottom surface  213  on an opposite side of the LGP  21  to the light emitting surface  211 . A light incident surface  215  of the LGP  21  is located perpendicular to the light emitting surface  211 . A protrusion  217  extends from a main body of the LGP  21 . A top of the protrusion  217  forms a part of the light emitting surface  211 , and a bottom of the protrusion  217  adjoins the light incident surface  215 . The LGP  21  having the protrusion  217  can be made by means of injection molding or milling. The protrusion  217  includes a lower surface  2171  adjoining the light incident surface  215 . The lower surface  2171  and the light incident surface  215  cooperatively define an accommodating space (not labeled) therebetween to accommodate the light source  23 . The light source  23  includes a lamp  231 , a U-shaped reflector  233  partially enclosing the lamp  231 , and two rubber blocks  235  disposed around two ends of the lamp  231  respectively. The lamp  231  can be a CCFL. When the light source  23  is accommodated in the accommodating space, the lamp  231  is adjacent to the light incident surface  215 . 
         [0023]    Also referring to  FIG. 3 , the reflector  233  includes a first sidewall  2331 , a third sidewall  2333 , and a second sidewall  2332  vertically connecting with the first sidewall  2331  and the third sidewall  2333 . The first sidewall  2331  contacts the lower surface  2171  of the protrusion  217 . The third sidewall  2333  is longer than the first sidewall  2331 , and extends under part of the bottom surface  213  of the LGP  21 . The two rubber blocks  235  are fittingly engaged in two ends of the reflector  233 , and contact the light incident surface  215  of the LGP  21 . 
         [0024]    In assembly of the backlight module  2 , first, the light source  23  is set in position on an assembly table. The LGP  21  is placed so that the protrusion  217  covers the light source  23 . The first sidewall  2331  abuts the lower surface  2171 , the third sidewall  2333  partially overlaps the bottom surface  213 , and the rubber blocks  235  contact the light incident surface  215 . Finally, the set of optical films  25  are put on the light emitting surface  211  of the LGP  21 . 
         [0025]    A portion of the light beams emitted by the light source  23  directly enter the LGP  21  through the light incident surface  215 . Another portion of the light beams travel to the reflector  233 , are reflected by the reflector  233 , and then enter the LGP  21  through the light incident surface  215 . The LGP  21  guides the light beams and transforms them into so-called surface light, which emits from the light emitting surface  211 . The set of optical films  25  is used for enhancing and diffusing the surface light. 
         [0026]    With the above-described configurations, the light source  23  is held firmly in position. In addition, both the reflector  233  and the rubber blocks  235  can absorb force that transmits from the LGP  21  to the lamp  231 . Therefore the lamp  231  is effectively protected from being damaged by shock sustained by the LGP  21 . Furthermore, the first sidewall  2331  of the reflector  233  abuts the lower surface  2171  of the protrusion  217 , and the third sidewall  2333  abuts part of the bottom surface  213  of the LGP  21 . Thus the light source  23  and the LGP  21  are held closely together, in order to eliminate phenomena such as light leakage, bright lines, and the like. Moreover, because the protrusion  217  is between the light source  23  and the set of optical films  25 , when the light source  23  is working, the protrusion  217  can absorb part of thermal energy emitted from the light source  23 . This can prevent the thermal energy from reaching the set of optical films  25 . Therefore, the set of optical films  25  is protected from distortion due to overheating. 
         [0027]      FIG. 4  is a side view of an LCD device which has the backlight module  2  installed therein. The LCD device  6  includes an LCD panel  7 , and the backlight module  2  disposed under the LCD panel  7 . The backlight module  2  is used for providing light beams to illuminate the LCD panel  7 . 
         [0028]    Referring to  FIG. 5 , this is a backlight module  3  according to a second embodiment of the present invention. The backlight module  3  has a structure similar to that of the backlight module  2 . However, an LGP  31  includes two light incident surfaces  315  at two opposite sides thereof. Two protrusions  317  are located at the two opposite sides of the LGP  31 . A top of each protrusion  317  forms a part of a light emitting surface  311 , and a bottom of each protrusion  317  adjoins the corresponding light incident surface  315 . The two light sources  33  are arranged under the two protrusions  317  respectively. 
         [0029]    Referring to  FIG. 6  and  FIG. 7 , a backlight module  4  according to a third embodiment of the present invention has a structure similar to that of the backlight module  2 . However, the backlight module  4  includes an LGP  41  and an L-shaped reflector  433 . A reflective layer  4172  is attached to a lower surface  4171  of a protrusion  417  of the LGP  41 . The reflective layer  4172  can be a film made of reflective material. Such film can for example be a coating of metallic material. The metallic material can be silver, zinc, or another suitable metal or alloy. The reflector  433  includes a first sidewall  4331 , and a second sidewall  4333  extending from the first sidewall  4331 . A top end of the first sidewall  4331  abuts the reflective layer  4172 . The second sidewall  4333  extends under part of the bottom surface  413  of the LGP  41 . 
         [0030]    In the assembly of the backlight module  4 , first, the light source  43  is set in position on an assembly table. The LGP  41  is placed so that the protrusion  217  covers the light source  43 . The top end of the first sidewall  4331  abuts the reflective layer  4172 , the second sidewall  4333  is engaged with part of the bottom surface  413 , and the rubber blocks  435  contact the light incident surface  415 . Finally, a set of optical films  45  are put on a light emitting surface  411  of the LGP  41 . The set of optical films  45  is used for enhancing and diffusing light beams emitting from the light emitting surface  411 . 
         [0031]    Because the backlight module  4  has the reflective layer  4172  attached on the lower surface  4171  of the protrusion  417 , as well as the reflector  433 , the backlight module  4  has a light weight construction. In addition, the backlight module  4  can achieve a high level of light utilization efficiency. Furthermore, when the light source  43  is working, the protrusion  417  can absorb part of thermal energy emitted from the light source  43 . This can prevent the thermal energy from reaching the set of optical films  45 . Therefore, the set of optical films  45  is protected from distortion due to overheating. 
         [0032]      FIG. 8  is an exploded, side view of a backlight module according  5  to a fourth embodiment of the present invention. The backlight module  5  has a structure similar to that of the backlight module  4 . However, an LGP  51  includes two light incident surfaces  515  at two opposite sides thereof. Two protrusions  517  are located at the two opposite sides of the LGP  31 . A top of each protrusion  317  forms a part of a light emitting surface  511 , and a bottom of each protrusion  317  adjoins the corresponding light incident surface  515 . Two light sources  53  are arranged under the two protrusions  517  respectively. 
         [0033]    The above-described LCD device  6  includes the backlight module  2  by way of example. It is to be understood that in alternative embodiments, the LCD device  6  can instead include any one of the above-described backlight modules  3 ,  4  and  5 . 
         [0034]    It is to be further understood that even though numerous characteristics and advantages of the present embodiments have been set out in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be 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 the appended claims are expressed.