Patent Document

BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a direct backlight module and in particular to a direct backlight module to overcome flexing of a diffuser and light sources.  
         [0003]     2. Description of the Related Art  
         [0004]      FIG. 1  is conventional direct backlight module  1  disclosed in Japanese Patent Publication No. 5-119703. The conventional backlight module  1  places a support  13  under an illumination tube  14  to overcome deformation thereof. Nevertheless, the size of the LCD panel (not shown) increases, the diffuser  11  must also be larger. The diffuser  11  is thus bent and deformed due to the heat from the illumination tube  14 , thereby impacting the optics of the direct backlight module  1 .  
         [0005]     Therefore, as shown in  FIG. 2 , in order to prevent flexing, several supports  23  are disposed between the reflecting plate  12  and the diffuser  11 . Thus, the optical character of the direct backlight module  1  is not affected and the illumination tubes  14  are not damaged by the flexed diffuser  11 . Nevertheless, as size of the LCD panel increases, the number of the supports  23  also increases. The supports  23  always partially obscure light affecting uniformity of the display.  
       SUMMARY OF THE INVENTION  
       [0006]     In order to address the disadvantages of the aforementioned backlight module, the present invention provides a direct backlight module utilizing a transparent support to prevent diffuser deformation.  
         [0007]     The direct backlight module of the present invention includes a diffuser, a reflecting plate, a plurality of light sources and at least one transparent support. The reflecting plate connects to the diffuser and forms a chamber therebetween, in which the light sources and transparent support are disposed. The transparent support supports the diffuser and the reflecting plate.  
         [0008]     The transparent support includes a retaining portion and connected supporting plate and is disposed between the diffuser and the reflecting plate.  
         [0009]     The supporting plate contacts the diffuser and the retaining portion connects to the reflecting plate.  
         [0010]     The retaining portion and the supporting plate are integrally formed.  
         [0011]     The transparent support is manufactured by injection molding.  
         [0012]     The supporting plate is a hollow frame.  
         [0013]     The plurality of light sources are lamps.  
         [0014]     The transparent support comprises a plurality of supporting units.  
         [0015]     The plurality of supporting units in the chamber are arranged in array.  
         [0016]     The plurality of supporting units in the chamber are arranged in concentric circles.  
         [0017]     Each supporting unit has a retaining portion and connected supporting plate and is disposed between the diffuser and the reflecting plate.  
         [0018]     The supporting plate contacts the diffuser and the retaining portion connects to the reflecting plate.  
         [0019]     The retaining portion and the supporting plate are integrally formed.  
         [0020]     The transparent support is manufactured by injection molding.  
         [0021]     The plurality of supporting units are hollow frames.  
         [0022]     The transparent support comprises a diffusion material.  
         [0023]     A diffusion material is coated on the at least one transparent support. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0024]     The present invention can be more fully understood by reading the subsequent detailed description in conjunction with the examples and references made to the accompanying drawings, wherein:  
         [0025]      FIG. 1  is a sectional view of a conventional direct backlight module;  
         [0026]      FIG. 2  is a sectional view of another conventional direct backlight module;  
         [0027]      FIG. 3  is a sectional view of a first embodiment in accordance with the present invention;  
         [0028]      FIGS. 4   a - 4   c  are top views of a first type transparent support in accordance with the first embodiment of the present invention;  
         [0029]      FIGS. 5   a - 5   b  are top views of a second type transparent support in accordance with the first embodiment of the present invention;  
         [0030]      FIGS. 6   a - 6   b  are top views of a second embodiment in accordance with the present invention;  
         [0031]      FIGS. 7   a - 7   b  are top views of a third embodiment in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0032]      FIG. 3  shows a sectional view of a first embodiment in accordance with the present invention, in which a direct backlight module  3  has a diffuser  31  connected to a reflecting plate  32 . A chamber  35  is formed between the diffuser  31  and the reflecting plate  32 . In the chamber  35 , a plurality of light sources  34  are disposed. In this embodiment, the plurality of light sources  34  are lamps. In order to overcome deformation of the diffuser  31  due to the size of the diffuser  31  and the heat from the light sources  34 , a transparent support  33  is disposed between the diffuser  31  and the reflecting plate.  
         [0033]     In the embodiment, the transparent support  33  is integrally formed by injection molding, comprising several retaining portions  331  connected to a supporting plate  332 . The flat supporting plate  332  fixes and retains the shape of the diffuser  31 . The retaining portions  331  are arranged between the light sources  34  according to diffusion requirements, supporting the supporting plate  332  and the diffuser  31 . The transparent supports  33  comprise transparent material to not affect the brightness of the backlight module. To further aid optical uniformity, the transparent supports  33  may also comprise diffusion material or such may be coated on the surface thereof.  
         [0034]     Furthermore, a first diffuser plate  36 , a prism  37  and a second diffuser plate  38  are disposed on the diffuser  31 . The first diffuser plate  36  is disposed on the diffuser  31 , the prism  37  is disposed on the first diffuser plate  36 , and the second diffuser plate  38  is disposed on the prism  37 , with amounts and sequences of disposition dictated by demand.  
         [0035]      FIGS. 4   a  to  4   c  show top views of a first type of transparent supports. The supporting plates  412 ,  422  and  432  of the transparent supports  41 ,  42  and  43  are respectively rectangular, circular and polygonal. The supporting plates  412 ,  422  and  432  are integrated with the retaining portions  411 ,  421  and  431  arranged thereunder. Shape of the supporting plates may be designed according to the diffuser used. The area of the transparent supports may be reduced to support the diffuser. Retaining portion numbers vary with demand. For example, the transparent support  42  with circular supporting plate  422 , as shown in  FIG. 4   b , has only one retaining portion disposed at the center of the supporting plate  422 .  
         [0036]      FIGS. 5   a  to  5   b  show top views of a second type of transparent supports.  FIGS. 5   a  to  5   b , the supporting plates  512  and  522  of the transparent supports  51  and  52  are, respectively, rectangular and circle hollow frames. The retaining portions  511  and  521  are arranged under the supporting plates  512  and  522 . Shape of the supporting plates can vary according to the diffuser. The design of the hollow frame can reduce the area of the transparent supports and decrease the overall weight of the direct backlight module while supporting the diffuser. A majority of light is directly emitted into the diffuser without passing through the supports, such that brightness of the direct backlight module is more uniform.  
         [0037]     In the present invention, the transparent supports are not limited to an integral type, and may be combined with several supporting units.  FIGS. 6   a  to  6   b  are top views of a second embodiment of a direct backlight module in accordance with the present invention. In  FIG. 6   a , the transparent support  60  of the direct backlight module  6  comprises two supporting units  61 . Each supporting unit  61  is formed by retaining portions  611  and a supporting plate  612 . The retaining portions  611  contact the reflecting plate (not shown), and the supporting plate  612  contacts the diffuser  62 . The supporting units  61  are arranged in array to support the diffuser.  FIG. 6   b  shows small-scale supporting units  63  arranged in array. The transparent support formed by the small-scale supporting units not only supports the diffuser but can also be conveniently transported. Further, the small-scale supporting units can vary with the size of the panel with the direct backlight module to reduce costs.  
         [0038]     In the present invention, the transparent supports are not limited to an integral type, and may be combined with several different sizes of supporting units.  FIGS. 7   a  to  7   b  are top views of a third embodiment of a direct backlight module in accordance with the present invention. In  FIG. 7   a , the transparent support  70  of the direct backlight module  7  comprises two supporting units  71  arranged in concentric circles. Each supporting unit  71  is formed by retaining portions  711  and a supporting plate  712 , a hollow frame. The retaining portions  711  contacts the reflecting plate (not shown), and the supporting plate  712  contacts the diffuser  72 . The supporting units  71  are arranged in concentric circles to support the diffuser. In  FIG. 7   b , the supporting units  73  constituting a transparent support  70  are arranged homocentrically. The transparent support  70  comprising the different sizes of supporting units  73  supports the diffuser and prevents deformation thereof. Further, the hollow design of the supporting plate not only reduces the area of the transparent supports but also weight of the direct backlight module  7 . A majority of light is directly emitted into the diffuser without passing through the supports, such that brightness of the direct backlight module is more uniform.  
         [0039]     According to the present invention, the transparent supports prevent the diffuser from deformation irrespective of the size thereof, affecting brightness.  
         [0040]     Finally, while the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.

Technology Category: 2