Patent Publication Number: US-2015077977-A1

Title: Backlight module and lcd

Description:
FIELD OF THE INVENTION 
     The present invention relates to a liquid crystal display (LCD) technology, and especially to a backlight module and an LCD. 
     BACKGROUND OF THE INVENTION 
     With a growing development in LCD production techniques, there are high demands for the production efficiency of the LCD. 
     Referring to  FIG. 1 ,  FIG. 1  is a schematic drawing illustrating a light-emitting diode (LED) backlight module in prior art. The backlight module herein includes an LED  11 , a printed circuit board (PCB)  12 , a conductive layer  13 , and pins  14 . The LED  11  has a light output surface  111 . 
     The LED  11  herein is disposed on the PCB  12 , and the conductive layer  13  is disposed on the inside of the PCB  12 . The LED  11  is coupled to the conductive layer  13  via the pins  14 . 
     When light emitted from the light output surface  111  of the LED  11  passes through optical films (not shown), a part of the light is reflected from the optical films. In order to effectively use the reflected light, a reflecting layer  15  is usually disposed on the conductive layer  13 . The reflecting layer  15  can further reflect the reflected light back to the optical films, so as to increase utilization rate of the light. 
     However, there is a reflecting region  16  between a surface where the light output surface  111  is located and the reflecting layer  15 . The reflecting region  16  has a reflecting height H1, which is a distance between the surface where the light output surface  111  of the LED  11  is located and the reflecting layer  15 . Due to the existence of the reflecting region  16 , the light reflected from the optical films largely dissipates in passing through the reflecting region  16 , such that the utilization rate of the light reflected from the optical films decreases. 
     Moreover, the pins  14  extend for a length H2 toward the LED  11  in a lengthwise direction A of the PCB  12 , and the reflecting layer  15  can not be disposed on the pins  14 . Thus, the reflecting layer  15  can not extend to a region where the pins  14  is located, such that the region can not reflect the reflected light, hence the utilization rate of the reflected light further decreases. 
     To solve the above-mentioned problem, a support bracket  17  is generally disposed between the reflecting layer  15  and the conductive layer  13 , as shown in  FIG. 2 . 
     In the backlight module shown in  FIG. 2 , the support brackets  17  support the reflecting layer  15 , so that the reflecting layer  15  is flush with the surface where the light output surface  111  of the LED  11  is located. This manner can prevent the light from dissipating due to the existence of the reflecting region  16 . 
     However, because plenty of space still exists between the light output surface  111  of the LED  11  and the optical films, the light dissipation still exists; thus, the light reflected from the optical films still can not be effectively utilized in this manner. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide an backlight module which can solve the drawback that the light reflected from the optical films can not be effectively utilized due to the plenty of space existing between the light output surface of the LED and the optical films in the backlight module of the prior art. 
     To achieve the foregoing objective, a backlight module constructed in the present invention includes a light source and a PCB. The light source is disposed on an inside of the PCB. The light source includes a light output surface, and the light output surface is parallel to the PCB with a light source distance therebetween. The backlight module further includes a reflector. A support bracket is disposed between the reflector and the PCB, and the support bracket is utilized to support and fix the reflector. 
     The reflector herein is disposed beside the light source, and the reflector has a reflecting layer. The reflecting layer herein has a curved surface, and the reflecting layer is outward curved in an opposite direction of the PCB. There is a maximum distance between the reflecting layer and the PCB, and the maximum distance is larger than the light source distance. 
     In the backlight module of the present invention, the reflector has a bottom, and there is a supporting distance between the bottom and the PCB. The supporting distance is less than the light source distance. 
     In the backlight module of the present invention, the curved surface is formed by a plurality of flat surfaces coupling each other. 
     In the backlight module of the present invention, the curved surface is an arced surface. 
     Another objective of the present invention is to provide an backlight module which can solve the drawback that the light reflected from the optical films can not be effectively utilized due to the plenty of space existing between the light output surface of the LED and the optical films in the backlight module of the prior art. 
     To achieve the foregoing objective, a backlight module constructed in the present invention includes a light source and a PCB. in which the light source is disposed on an inside of the PCB. The light source includes a light output surface, and the light output surface is parallel to the PCB with a light source distance therebetween. The backlight module further includes a reflector. 
     The reflector is disposed beside the light source, and the reflector has a reflecting layer. The reflecting layer is outward curved in an opposite direction of the PCB. There is a maximum distance between the reflecting layer and the PCB, and the maximum distance is larger than the light source distance. 
     In the backlight module the present invention, a support bracket is disposed between the reflector and the PCB, and the support bracket is utilized to support and fix the reflector. 
     In the backlight module the present invention, the reflector has a bottom. There is a supporting distance between the bottom and the PCB, and the supporting distance is less than the light source distance. 
     In the backlight module the present invention, the reflecting layer has a curved surface. 
     In the backlight module the present invention, the curved surface is formed by a plurality of flat surfaces coupling each other. 
     In the backlight module the present invention, the curved surface is an arced surface. 
     Yet another objective of the present invention is to provide an LCD which can solve the drawback that the light reflected from the optical films can not be effectively utilized due to the plenty of space existing between the light output surface of the LED and the optical films in the backlight module of the prior art. 
     To achieve the foregoing objective, an LCD constructed in the present invention includes a backlight module. The backlight module includes a light source and a PCB, in which the light source is disposed on an inside of the PCB. The light source includes a light output surface, and the light output surface is parallel to the PCB with a light source distance therebetween. The backlight module further includes a reflector. 
     The reflector is disposed beside the light source, and the reflector has a reflecting layer. The reflecting layer is outward curved in an opposite direction of the PCB. There is a maximum distance between the reflecting layer and the PCB, and the maximum distance is larger than the light source distance. 
     In the LCD of the present invention, a support bracket is disposed between the reflector and the PCB, and the support bracket is utilized to support and fix the reflector. 
     In the LCD of the present invention, the reflector has a bottom, and there is a supporting distance between the bottom and the PCB. The supporting distance is less than the light source distance. 
     In the LCD of the present invention, the reflecting layer has a curved surface. 
     In the LCD of the present invention, the curved surface is formed by a plurality of flat surfaces coupling each other. 
     In the LCD of the present invention, the curved surface is an arced surface. 
     In comparison with the prior art, the reflecting layer of the reflector is configured to be arranged in the curved surface according to the present invention, and the maximum distance between the reflecting layer and the PCB is larger than the distance between the light source light output surface and the PCB. As a result, paths that the light reflected from the optical films reaches the reflector are reduced, so that the light dissipation resulting from the reflected light with long paths can be avoided. Thus, the utilization rate of the light reflected from the optical films is increased, thereby increasing luminous efficiency of the backlight module. 
     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic drawing illustrating a backlight module in prior art; 
         FIG. 2  is a schematic drawing illustrating another backlight module in prior art; 
         FIG. 3  a schematic drawing illustrating a backlight module according to a first preferred embodiment of the present invention; 
         FIG. 4  is a schematic drawing illustrating a light source, pins, and a conductive layer in  FIG. 3 ; 
         FIG. 5  is a schematic sectional view illustrating a reflector in  FIG. 3 ; 
         FIG. 6  is a schematic drawing illustrating a reflecting layer of the reflector in  FIG. 3 ; 
         FIG. 7  is a schematic drawing illustrating a backlight module according to a second preferred embodiment of the present invention; and 
         FIG. 8  is a schematic drawing illustrating a backlight module according to a third preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Descriptions of the following embodiments refer to attached drawings which are utilized to exemplify specific embodiments. Directional terms mentioned in the present invention, such as “top” and “down” “front”, “rear”, “left”, “right”, “inside”, “outside”, “side” and so on are only directions with respect to the attached drawings. Therefore, the used directional terms are utilized to explain and understand the present invention but not to limit the present invention. In different drawings, the same reference numerals refer to like parts throughout the drawings. 
       FIG. 3  is a schematic drawing illustrating a backlight module according to a first preferred embodiment of the present invention. 
     The backlight module includes a light source  31 , a PCB  32 , a conductive layer  33 , pins  34 , reflectors  35 , and support brackets  36 . The light source  31  includes a light output surface  311 , and the backlight module further includes optical film  40 . 
     The light source  31  herein is disposed on the PCB  32 , and the light output surface  311  of the light source  31  is parallel to the PCB  32 . The conductive layer  33  is disposed on an inside of the PCB  32 . Referring to  FIG. 4  with  FIG. 3 , the conductive layer  33  includes a first conductive layer  331 and a second conductive layer  332 . The first conductive layer  331  and the second conductive layer  332  are respectively disposed on both sides of the light source  31 . 
     The pins  34  include a first pin  341  and a second pin  342 . The light source  31  is coupled to the first conductive layer  331  via the first pin  341 , and coupled to the second conductive layer  332  via the second pin  342 . 
     Referring to  FIG. 4  again, using the first pin  341  as an example, the first pin  341  is a bending structure which includes a first bending port  3411  and a second bending part  3412 . The first bending port  3411  abuts on a side  312  of the light source  31 , and the second bending port  3412  abuts on a bottom side  313  of the light source  31 . Furthermore, the second bending part  3412  is simultaneously coupled to the first conductive layer  331  for realizing signal transmission between the PCB  32  and the light source  31 . The second pin  342  has the same structure and function as the first pins  341 , so no further detail will be provided herein. 
     The pins  34  of the present invention are designed to be the bending structures, which respectively abut the side and the bottom side of the light source  31 , for coupling to the bottom side of the light source  31  and simultaneously coupling to the conductive layer  33 . It does not need too much space, and it is a disadvantage to the arrangement of other components within the backlight module. For example, the support bracket  36  can be flexibly disposed beside the light source  31 . 
     Referring back to  FIG. 3 , the support bracket  36  is disposed between the PCB  32  and the reflector  35 . More specifically, it is disposed between the conductive layer  33  and the reflector  35 . In the embodiment, the support bracket  36  is utilized to support and fix the reflector  35 . 
     Referring to  FIG. 5  with the foregoing drawings, the reflector  35  includes a reflector body  351 , and includes a bottom  352  and a reflecting layer  353  located at a surface layer of the reflector body  351 . The bottom  352  herein is parallel to the PCB  32 , so that the support bracket  36  can stably support the reflector  35 . 
     Referring back to  FIG. 3 , there is a supporting distance L1 between the bottom  352  and the PCB  32 ; there is a light source distance L2 between the light output surface  311  of the light source  31  and the PCB  32 ; and there is a maximum distance L3 between the reflecting layer  353  and the PCB  32 , in which L1≦L2, and L2&lt;L3. The condition of L1≦L2 in the present invention can ensure that the light emitted from the light source  31  can not be incident on the bottom  352  of the reflector  35 . The condition of L2&lt;L3 in the present invention can reduce the paths that the light reflected from the optical film  40  reaches the reflector  35 , so as to increase the utilization rate of the light. 
     Moreover, he supporting distance L1 and the light source distance L2 are within a predetermined range, such as 1.0 mm to 5.0 mm, thereby ensuring that the light reflected from the optical film  40  can be utilized effectively. 
     In the present invention, the reflecting layer  353  is a curved surface reflecting layer. For instance, the reflecting layer  353  can have a curved surface structure formed by a plurality of flat surfaces being coupled with each other and bent. In the first preferred embodiment, the flat surfaces are bent to form a triangle structure, such as the reflecting layer  353  shown in  FIG. 6 . 
     The operating principle of the backlight module of the first preferred embodiment shown in  FIG. 3  to  FIG. 6  is as follows. 
     In working processes of the backlight module, after the light emitted from the light source  31  reaches the optical film  40 , most of the light passes through the optical film  40 , but a part of the light still&#39;is reflected from the optical film  40 . 
     The above-mentioned light reflected from the optical film  40  is incident on the reflector  35 , and then goes back to and passes through the optical film  40  after being reflected by the reflecting layer  353  of the reflector  35 . 
     Because of the support of the support bracket  36 , the support bracket  36  is closer to the optical film. Moreover, the reflecting layer  353  of the reflector  35  is configured to bend in the curved surface, and the maximum distance L3 between the reflecting layer  353  and the PCB  32  is larger than the light source distance L2 between the light output surface  311  of the light source  31  and the PCB  32 , so that the reflecting layer  353  is more closer to the optical film  40  for extremely reducing the distance that the light reflected from the optical film  40  reaches the reflector  35 . Thus, the light dissipation due to the excessive distance can be avoided, and the light reflected from the optical film  40  can be effectively utilized, so as to increase the luminous efficiency of the backlight module. 
       FIG. 7  is a schematic drawing illustrating a backlight module according to a second preferred embodiment of the present invention. The difference between the second embodiment and the first embodiment shown in  FIG. 3  is that the reflecting layer  354  of the reflector  35  in the second embodiment as shown in  FIG. 7  has a curved surface structure formed by the plurality of flat surfaces being bent, and the flat surfaces are bent to form a trapezoid structure. 
     The structure and operating principle with regard to the second preferred embodiment as shown in  FIG. 7  please refer to the description for the first preferred embodiment as shown in  FIG. 3 , so no further detail will be provided herein. 
       FIG. 8  is a schematic drawing illustrating a backlight module according to a third preferred embodiment of the present invention. The difference between the third embodiment and the first embodiment shown in  FIG. 3  is that the reflecting layer  355  of the reflector  35  in the third embodiment as shown in  FIG. 8  is an arced surface reflecting layer. 
     The structure and operating principle with regard to the third preferred embodiment as shown in  FIG. 8  please refer to the description for the first preferred embodiment as shown in  FIG. 3 , so no further detail will be provided herein. 
     An LCD is further provided in the present invention. The LCD includes the backlight module which is provided in the present invention. Whereas the backlight module has been described in detail mentioned above, no further detail will be provided herein. 
     In comparison with the prior art, the reflecting layer of the reflector is configured to be arranged in the curved surface according to the present invention, and the maximum distance between the reflecting layer and the PCB is larger than the distance between the light source light output surface and the PCB. As a result, paths that the light reflected from the optical films reaches the reflector are reduced, so that the light dissipation resulting from the reflected light with long paths can be avoided. Thus, the utilization rate of the light reflected from the optical films is increased, thereby increasing luminous efficiency of the backlight module. 
     While the preferred embodiments of the present invention have been illustrated and described in detail, various modifications and alterations can be made by persons skilled in this art. The embodiment of the present invention is therefore described in an illustrative but not restrictive sense. It is intended that the present invention should not be limited to the particular forms as illustrated, and that all modifications and alterations which maintain the spirit and realm of the present invention are within the scope as defined in the appended claims.