Abstract:
A diffusion plate having a surface microstructure comprises a plate and at least one microstructure, wherein the plate is made of a light-transmitting polymer having a UV absorbent and several diffusion particles doped therein. The microstructure is formed on at least one surface of the plate. By the use of the above-mentioned structure, the present invention can promote the diffusion capability of the diffusion plate and improve the diffusion plate&#39;s ability to cover the lamps.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a diffusion plate having a surface microstructure, and more particularly to a diffusion plate that utilizes the microstructure formed on the surface to provide many advantages including high light transmission rate, promoted diffusion capability and uniform light beams. 
       BACKGROUND OF THE INVENTION 
       [0002]    The modern people generally pick and purchase the LCD monitors, which are light and thin and not occupy too much space. In addition, they always aspire after larger size screen and lower price. As a result, the direct backlight modules, which apply to the large-size LCD monitors, have an increase in quantity demand year by year. In addition, the technical requirement for the direct backlight modules is also increased gradually. At present, all backlight module manufactures are diligent in developing new technology to promote the market competitiveness in the highly developed and competitive photoelectric industry for increasing the efficiency and reducing the cost. 
         [0003]    However, the direct type backlight module must employ a critical component, namely, a diffusion plate. The conventional diffusion plate is flat and made of transparent polymer, for example, PMMA, PC, PS, or MS. In addition, the transparent polymer is doped with diffusion particles, and extruded into a diffusion substrate. Thereafter, the diffusion substrate is cut to obtain the required shape and size. 
         [0004]    By the use of the aforesaid technology, the diffusion plate is provided with ability to cover the lamps and distribute the light uniformly. But, with the decrease of lamps in the 32 inches LCD TV, for example, from sixteen lamps to twelve lamps, the diffusion plate relatively requires a more powerful ability to cover the lamps instead of utilizing the diffusion particles alone. Accordingly, the diffusion ability of the diffusion plate and its ability to cover the lamps are needed to be improved. 
       SUMMARY OF THE INVENTION 
       [0005]    It is a primary object of the present invention to provide a diffusion plate having a surface microstructure, wherein the plate has several diffusion particles doped therein and the microstructure is formed on the outer surface of the plate in such a way that the light beams inside the diffusion plate can be reflected, refracted and scattered many times to provide the diffusion plate with high light transmission rate and improved diffusion capability for uniforming the light beams. 
         [0006]    In order to achieve the above and other objects, a diffusion plate having a surface microstructure of the present invention is comprised of a plate and at least one microstructure, wherein the plate is made of a light-transmitting polymer, which has a UV absorbent and several diffusion particles doped therein. The microstructure is formed on at least one surface of the plate. 
         [0007]    By the use of the above-mentioned structure, the present invention can overcome the conventional drawbacks so as to provide many advantages including high light transmission rate, promoted diffusion capability and uniform light beams. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a side view showing an internal structure of a diffusion plate in accordance with a first preferred embodiment of the present invention. 
           [0009]      FIG. 2  is an elevational view showing a microstructure and another microstructure, which are perpendicular to each other on the diffusion plate of the present invention. 
           [0010]      FIG. 3  is an elevational view showing a microstructure and another microstructure, which are parallel to each other on the diffusion plate of the present invention. 
           [0011]      FIG. 4  is a side view showing a partial enlarged diagram of the microstructure formed on the diffusion plate in accordance with the first preferred embodiment of the present invention. 
           [0012]      FIG. 5  is a side view showing a partial enlarged diagram of the microstructure formed on the diffusion plate in accordance with a second preferred embodiment of the present invention. 
           [0013]      FIG. 6  is a side view showing a partial enlarged diagram of the microstructure formed on the diffusion plate in accordance with a third preferred embodiment of the present invention. 
           [0014]      FIG. 7  is a side view showing a partial enlarged diagram of the microstructure formed on the diffusion plate in accordance with a fourth preferred embodiment of the present invention. 
           [0015]      FIG. 8  is a side view showing a partial enlarged diagram of the microstructure formed on the diffusion plate in accordance with a fifth preferred embodiment of the present invention. 
           [0016]      FIG. 9  is a side view showing a partial enlarged diagram of the microstructure formed on the diffusion plate in accordance with a sixth preferred embodiment of the present invention. 
           [0017]      FIG. 10  is a side view showing a partial enlarged diagram of the microstructure formed on the diffusion plate in accordance with a seventh preferred embodiment of the present invention. 
           [0018]      FIG. 11  is a side view showing a partial enlarged diagram of the microstructure formed on the diffusion plate in accordance with an eighth preferred embodiment of the present invention. 
           [0019]      FIG. 12  is a side view showing a partial enlarged diagram of the microstructure formed on the diffusion plate in accordance with a ninth preferred embodiment of the present invention. 
           [0020]      FIG. 13  is a side view showing an internal structure of a diffusion plate in accordance with a tenth preferred embodiment of the present invention. 
           [0021]      FIG. 14  is a side view showing an internal structure of a diffusion plate in accordance with a nineteenth preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    Before explaining the present invention in more detail, it deserves to be specially noted that identical or analogous parts in the following description are generally indicated by identical reference numerals. 
         [0023]    Referring to  FIGS. 1 through 4 , a diffusion plate having a surface microstructure in accordance with a first preferred embodiment of the present invention comprises a plate  1  and at least one microstructure  2 . 
         [0024]    The plate  1  is made of a light-transmitting polymer, which is polymethylmethacrylate (PMMA), polycarbonate (PC), methylmethacrylate/styrene copolymer (MS resin), or polystyrene (PS). In addition, the plate  1  has a UV absorbent  11  doped therein to prevent the direct UV light irradiation from causing the plate  1  to generate the phenomena of photoyellowing and cracking. In addition, the plate  1  has several diffusion particles  12  doped therein, wherein the diffusion particles  12  are polymethylmethacrylate (PMMA), polycarbonate (PC), titanium dioxide (TiO 2 ), or silicon dioxide (SiO 2 ). As a result, the phenomenon of optical diffusion occurs when the light passes through the diffusion particles  12 . 
         [0025]    The microstructure  2  is formed on at least one surface of the aforesaid plate  1 . In this preferred embodiment, this microstructure  2  and another microstructure  2  are arranged parallel (shown in  FIG. 2 ) or perpendicular (shown in  FIG. 3 ) to each other. Each of the microstructures comprises a plurality of parallel-arranged sine-wave bars  21 , and the depth D between the peak and the trough of every sine-wave bar  21  is ranged between 0.01 mm and 0.3 mm, preferably between 0.05 mm and 0.15 mm. The distance P between two adjacent sine-wave bars  21  is ranged between 0.05 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm. The angle α shown in the figure is ranged between 120 degrees and 180 degrees. The symbol R shown in the figure is ranged between 0.43×P and 0.5×P. 
         [0026]    Referring to  FIG. 5 , a diffusion plate of a second preferred embodiment of the present invention has a configuration similar to that of the first preferred embodiment. The difference is that the microstructure  2  of the second preferred embodiment has several parallel-arranged triangular bars  22 . The depth D between the peak and the trough of every triangular bar  22  is ranged between 0.01 mm and 0.3 mm, preferably between 0.05 mm and 0.15 mm. The distance P between two adjacent triangular bars  22  is ranged between 0.05 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm. The angle α shown in the figure is ranged between 90 degrees and 130 degrees. 
         [0027]    Referring to  FIG. 6 , a diffusion plate of a third preferred embodiment of the present invention has a configuration similar to that of the first preferred embodiment. The difference is that the microstructure  2  of the third preferred embodiment has several parallel-arranged semi-spherical bars  23 . The depth D between the peak and the trough of every semi-spherical bar  23  is ranged between 0.01 mm and 0.3 mm, preferably between 0.05 mm and 0.15 mm. The distance P between two adjacent semi-spherical bars  23  is ranged between 0.05 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm. The angle α shown in the figure is ranged between 120 degrees and 180 degrees. The symbol R shown in the figure is ranged between 0.43×P and 0.5×P. 
         [0028]    Referring to  FIG. 7 , a diffusion plate of a fourth preferred embodiment of the present invention has a configuration similar to that of the first preferred embodiment. The difference is that the microstructure  2  of the fourth preferred embodiment has several parallel-arranged polygonal bars  24 . The depth D between the highest point and the lowest point of every polygonal bar  24  is ranged between 0.01 mm and 0.3 mm, preferably between 0.05 mm and 0.15 mm. The distance P between the centers of two adjacent polygonal bars  24  is ranged between 0.05 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm. The angle α shown in the figure is ranged between 120 degrees and 180 degrees. The symbol R 1  shown in the figure is ranged between 0.43×P and 0.5×P. The symbol R 2  shown in the figure is ranged between 0.5×R 1  and R 1 . 
         [0029]    Referring to  FIG. 8 , a diffusion plate of a fifth preferred embodiment of the present invention has a configuration similar to that of the first preferred embodiment. The difference is that the microstructure  2  of the fifth preferred embodiment has several parallel-arranged bars  25  and several trenches  26 , wherein each trench  26  is formed between two adjacent bars  25 . The depth D between the highest point of the bar  25  and the lowest point of the trench  26  is ranged between 0.01 mm and 0.3 mm, preferably between 0.05 mm and 0.15 mm. The distance P between the centers of two adjacent bars  25  is ranged between 0.05 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm. The symbol R 1  shown in the figure is ranged between 0.43×P and 0.5×P. The symbol R 2  shown in the figure is ranged between 0.1×R 1  and 0.15×R 1 . 
         [0030]    Referring to  FIG. 9 , a diffusion plate of a sixth preferred embodiment of the present invention has a configuration similar to that of the first preferred embodiment. The difference is that the microstructure  2  of the sixth preferred embodiment has several parallel-arranged reflection bars  27  and several reflection trenches  28 , wherein every trench  28  is formed between two adjacent reflection bars  27 . The depth D between the highest point of the reflection bar  27  and the lowest point of the reflection trench  28  is ranged between 0.01 mm and 0.3 mm, preferably between 0.05 mm and 0.15 mm. The distance P between the centers of two adjacent reflection bars  27  is ranged between 0.05 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm. The symbol R 1  shown in the figure is ranged between 0.43×P and 0.5×P. The symbol R 2  shown in the figure is ranged between 0.5×R 1  and R 1 . 
         [0031]    Referring to  FIG. 10 , a diffusion plate of a seventh preferred embodiment of the present invention has a configuration similar to that of the first preferred embodiment. The difference is that the microstructure  2  of the seventh preferred embodiment has several parallel-arranged semi-waveform bars  29 . The depth D between the highest point and the lowest point of every semi-waveform bar  29  is ranged between 0.01 mm and 0.3 mm, preferably between 0.05 mm and 0.15 mm. The distance P between the centers of two adjacent semi-waveform bars  29  is ranged between 0.05 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm. The angle α shown in the figure is ranged between 90 degrees and 130 degrees. The symbol R shown in the figure is ranged between 0.1×P and 0.5×P. 
         [0032]    Referring to  FIG. 11 , a diffusion plate of an eighth preferred embodiment of the present invention has a configuration similar to that of the first preferred embodiment. The difference is that the microstructure  2  of the eighth preferred embodiment has several parallel-arranged polygonal semi-waveform bars  2   a . The depth D between the highest point and the lowest point of every polygonal semi-waveform bar  2   a  is ranged between 0.01 mm and 0.3 mm, preferably between 0.05 mm and 0.15 mm. The distance P between the centers of two adjacent polygonal semi-waveform bars  2   a  is ranged between 0.05 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm. The angles α 1  and α 2  shown in the figure are ranged between 90 degrees and 150 degrees. 
         [0033]    Referring to  FIG. 12 , a diffusion plate of a ninth preferred embodiment of the present invention has a configuration similar to that of the first preferred embodiment. The difference is that the microstructure  2  of the ninth preferred embodiment has several parallel-arranged irregular semi-wave bars  2   b . The depth D between the highest point and the lowest point of every irregular semi-wave bar  2   b  is ranged between 0.01 mm and 0.3 mm, preferably between 0.05 mm and 0.15 mm. The distance P between the centers of two adjacent irregular semi-wave bars  2   b  is ranged between 0.05 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm. The angle α shown in the figure is ranged between 120 degrees and 180 degrees. The symbol R 1  shown in the figure is ranged between 0.43×P and 0.5×P. The symbol R 2  shown in the figure is ranged between 0.5×R 1  and 0.8×R 1 . 
         [0034]    Referring to  FIGS. 4 and 13 , a diffusion plate having a surface microstructure in accordance with a tenth preferred embodiment of the present invention comprises a plate  1  and at least one microstructure  2 . 
         [0035]    The plate  1  is made of a light-transmitting polymer, which is polymethylmethacrylate (PMMA), polycarbonate (PC), methylmethacrylate/styrene copolymer (MS resin), or polystyrene (PS). The plate  1  comprises a core layer  13 , a first auxiliary layer  14  formed on the top of the core layer  13 , and a second auxiliary layer  15  formed on the bottom of the core layer  13 . A UV absorbent  11  is doped into the core layer  13  or one of the first auxiliary layer  14  and the second auxiliary layer  15  to prevent the direct UV light irradiation from causing the plate  1  to generate the phenomena of photoyellowing and cracking. Several diffusion particles  12  are doped into the other one, wherein the diffusion particles  12  are polymethylmethacrylate (PMMA), polycarbonate (PC), titanium dioxide (TiO 2 ), or silicon dioxide (SiO 2 ). As a result, the phenomenon of optical diffusion occurs when the light passes through the diffusion particles  12 . 
         [0036]    The microstructure  2  is formed on at least one of the core layer  13 , the first auxiliary layer  14 , and the second auxiliary layer  15  of the plate  1 . This microstructure  2  and another microstructure  2  are perpendicular (shown in  FIG. 2 ) to each other. Each of the microstructures comprises a plurality of parallel-arranged sine-wave bars  21 . The distance range of the sine-wave bar  21  is identical to that of the sine-wave bar  21  of the first preferred embodiment. 
         [0037]    Referring to  FIG. 5 , a diffusion plate of an eleventh preferred embodiment of the present invention has a configuration similar to that of the tenth preferred embodiment. The difference is that the microstructure  2  of the eleventh preferred embodiment has several parallel-arranged triangular bars  22 . The distance range of the microstructure  2  of the eleventh preferred embodiment is identical to that of the microstructure  2  of the second preferred embodiment. 
         [0038]    Referring to  FIG. 6 , a diffusion plate of a twelfth preferred embodiment of the present invention has a configuration similar to that of the tenth preferred embodiment. The difference is that the microstructure  2  of the twelfth preferred embodiment has several parallel-arranged semi-spherical bars  23 . The distance range of the microstructure  2  of the twelfth preferred embodiment is identical to that of the microstructure  2  of the third preferred embodiment. 
         [0039]    Referring to  FIG. 7 , a diffusion plate of a thirteenth preferred embodiment of the present invention has a configuration similar to that of the tenth preferred embodiment. The difference is that the microstructure  2  of the thirteenth preferred embodiment has several parallel-arranged polygonal bars  24 . The distance range of the microstructure  2  of the thirteenth preferred embodiment is identical to that of the microstructure  2  of the fourth preferred embodiment. 
         [0040]    Referring to  FIG. 8 , a diffusion plate of a fourteenth preferred embodiment of the present invention has a configuration similar to that of the tenth preferred embodiment. The difference is that the microstructure  2  of the fourteenth preferred embodiment has several parallel-arranged bars  25  and several trenches  26 , wherein each trench  26  is formed between two adjacent bars  25 . The distance range of the microstructure  2  of the fourteenth preferred embodiment is identical to that of the microstructure  2  of the fifth preferred embodiment. 
         [0041]    Referring to  FIG. 9 , a diffusion plate of a fifteenth preferred embodiment of the present invention has a configuration similar to that of the tenth preferred embodiment. The difference is that the microstructure  2  of the fifteenth preferred embodiment has several reflection bars  27  and several reflection trenches  28 , wherein each reflection trench  28  is formed between two adjacent reflection bars  27 . The distance range of the microstructure  2  of the fifteenth preferred embodiment is identical to that of the microstructure  2  of the sixth preferred embodiment. 
         [0042]    Referring to  FIG. 10 , a diffusion plate of a sixteenth preferred embodiment of the present invention has a configuration similar to that of the tenth preferred embodiment. The difference is that the microstructure  2  of the sixteenth preferred embodiment has several semi-waveform bars  29 . The distance range of the microstructure  2  of the sixteenth preferred embodiment is identical to that of the microstructure  2  of the seventh preferred embodiment. 
         [0043]    Referring to  FIG. 11 , a diffusion plate of a seventeenth preferred embodiment of the present invention has a configuration similar to that of the tenth preferred embodiment. The difference is that the microstructure  2  of the seventeenth preferred embodiment has several polygonal semi-waveform bars  2   a . The distance range of the microstructure  2  of the seventeenth preferred embodiment is identical to that of the microstructure  2  of the eighth preferred embodiment. 
         [0044]    Referring to  FIG. 12 , a diffusion plate of an eighteenth preferred embodiment of the present invention has a configuration similar to that of the tenth preferred embodiment. The difference is that the microstructure  2  of the eighteenth preferred embodiment has several irregular semi-waveform bars  2   b . The distance range of the microstructure  2  of the eighteenth preferred embodiment is identical to that of the microstructure  2  of the ninth preferred embodiment. 
         [0045]    Referring to  FIGS. 4 ,  5  and  14 , a diffusion plate of an nineteenth preferred embodiment of the present invention has a configuration similar to that of the tenth preferred embodiment. The difference is that a microstructure  2 , which has several parallel-arranged sine-wave bars  21 , is formed on the top of the first auxiliary layer  14  of the nineteenth preferred embodiment. In addition, another microstructure  2 , which has several parallel-arranged triangular bars  22 , is formed on the bottom of the second auxiliary layer  15 . As a result, the microstructure  2  of the tenth preferred embodiment and the microstructure  2  of the nineteenth preferred embodiment can be utilized together. In addition, the microstructures of the above-mentioned preferred embodiments may be utilized cooperatively so as to form varied microstructure  2  on the surface of the plate  1 .