Abstract:
The present invention disclosed a backlight module comprising a light collection system, a light guide plate and a plurality of optical fibers, wherein all light incident ends of the plurality of optical fibers are connected to the light collection system for receiving sunlight; the backlight module further includes an optical fiber connector; the plurality of optical fibers are arranged in parallel on the surface of the light guide plate, with all their light emitting ends flush with the light incident end of the light guide plate; the optical fiber connector abuts against the light emitting end of the plurality of optical fibers and the light incident end of the light guide plate, respectively, used for guiding the sunlight emitting from the light emitting end of the plurality of optical fibers to enter the light guide plate from the light incident end of the light guide plate.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a backlight module, particularly to an optical-fiber type backlight module using sunlight as the backlight source. 
       BACKGROUND OF THE INVENTION 
       [0002]    The backlight source of an existing TFT-LCD display system, such as the common light-emitting diode or fluorescent tube, mostly uses power source devices such as city power or batteries as a drive unit, having high power consumption and not conducive to energy saving and environmental protection. 
         [0003]    In order to reduce energy consumption of the backlight source, there emerges on the market now a backlight module that can use sunlight as the energy source, which collects the sunlight including the visible band desired by the backlight source by using a light collection system and uses the fiber imported backlight module as the backlight source. However, during transportation of such a backlight module, in order to ensure that the optical fiber will not be damaged in the long-distance transportation, a thick film is usually packed at the outside of an optical cable composed of a plurality of bare optical fibers. While installing such a backlight module, in order to import a plurality of optical fibers into the backplane, the bare optical fibers in the optical cable need to be detached from the film and separated one by one, so as to attach to the light guide plate dispersedly, which greatly increases the amount of labor of transportation and assembly. Besides that, because the bare optical fiber used for transferring sunlight is made of quartz material that has poor flexibility, an extended backplane is usually needed, so as to carry and protect the bare optical fiber. However, this will greatly increase the length of the backplane, not only increasing weight of the backplane but also affecting the appearance; besides that, because of increase of area of the backplane, the ratio of the area of the display region of the liquid crystal display to the area of the panel may become less. 
       SUMMARY OF THE INVENTION 
       [0004]    The technical problem to be solved by the present invention is to provide a solar backlight module that is more convenient in transportation and assembly, simpler in structure, and conducive to miniaturization, so as to overcome the above defects of the solar backlight module in the prior art. 
         [0005]    The present invention adopts the following technical solution to solve its technical problem: a backlight module, comprising a light collection system, a light guide plate and a plurality of optical fibers, all light incident ends of the plurality of optical fibers are connected to the light collection system for receiving sunlight; the backlight module further includes an optical fiber connector; the plurality of optical fibers are arranged in parallel on a surface of the light guide plate, with all their light emitting ends flush with a light incident end of the light guide plate; the optical fiber connector abuts against the light emitting end of the plurality of optical fibers and the light incident end of the light guide plate, respectively, used for guiding the sunlight emitting from the light emitting end of the plurality of optical fibers to enter the light guide plate from the light incident end of the light guide plate. 
         [0006]    Preferably, the optical fiber connector is an isosceles right triangle, whose right angle is opposite to a mirror that abuts against the light emitting end of the plurality of optical fibers and the light incident end of the light guide plate. 
         [0007]    Preferably, a light emitting direction of the light emitting end of the plurality of optical fibers is perpendicular to the mirror to which the right angle of the isosceles right triangle prism is opposite. 
         [0008]    Preferably, the optical fiber connector is a half-cylindrical lens, whose flat mirror abuts against the light emitting end of the plurality of optical fibers and the light incident end of the light guide plate. 
         [0009]    Preferably, the light emitting direction of the light emitting end of the plurality of optical fibers is perpendicular to the flat mirror of the half-cylindrical lens. 
         [0010]    Preferably, the material of the optical fiber connector is selected from at least one of the group consisting of glass, polymethyl methacrylate or engineering plastics, and the refractive index of the optical fiber connector is in the range of 1.4-1.6. 
         [0011]    Preferably, the optical fiber connector includes two plane mirrors perpendicular to each other, one of the two plane mirrors abutting at its mirror face against the light emitting end of the plurality of optical fibers, the other mirror abutting at its mirror face against the light incident end of the light guide plate. 
         [0012]    Preferably, the light emitting direction of the light emitting end of the plurality of optical fibers forms an angle of 45° with the plane mirror. 
         [0013]    Preferably, the backlight module further includes an optical film, which is laminated on the other surface of the light guide plate opposite to the surface of the light guide plate on which the plurality of the optical fibers are arranged, so as to adjust brightness and visual angle of the backlight module. 
         [0014]    Preferably, the plurality of optical fibers are bonded to each other. 
         [0015]    With the backlight module of the present invention, the optical fiber can be arranged on the back of the light guide plate by increasing the number of the optical fiber connector, and the sunlight in the optical fiber can be directly imported into the light guide plate through the optical fiber connector, with the bare optical fibers in the optical fiber not necessary to be separated, thus neither the length of the backplane needing to be increased nor the ratio of the area of the display region being reduced. Meanwhile, the backlight module is allowed to be more convenient in transportation and assembly, simpler in structure, and more esthetic in appearance. 
     
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0016]    The present invention will further be explained below with reference to drawings and examples. In the drawings: 
           [0017]      FIG. 1  is a structural schematic diagram of the backlight module provided by example 1 of the present invention; 
           [0018]      FIG. 2  is a structural schematic diagram of the backlight module as shown in  FIG. 1  in another direction; 
           [0019]      FIG. 3  is a structural schematic diagram of the backlight module provided by example 2 of the present invention; and 
           [0020]      FIG. 4  is a structural schematic diagram of the backlight module provided by example 3 of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0021]    The backlight module of the present invention is directed to an improvement in the optical-fiber type backlight module using sunlight as the backlight source, and includes a light collection system, a light guide plate, an optical fiber connector, and a plurality of optical fibers, wherein the light collection system is used for converging sunlight into the optical fiber, the plurality of optical fibers are arranged horizontally in parallel below the light guide plate, and the optical fiber connector changes the transfer direction of the sunlight from the plurality of optical fibers by 180 degrees before importing it into the light guide plate. Thus, a backlight module with a narrow frame using sunlight as the light source can be obtained while saving energy; when the sunlight in the optical fiber is transferred to the light guide plate, all the bare optical fibers packed together are not necessary to be separated one by one before being connected to the light guide plate, and then the backplane carrying the light guide plate is not necessary to be extended for carrying and protecting the bare optical fiber. Further, using the backlight module of the present invention can reduce frame thickness and backplane length of the backlight module, reduce weight and cost of the backlight module, improve appearance of the backlight module, and reduce the transmission loss. 
         [0022]    In the preferred example of the present invention, a plurality of optical fibers can first be bonded together, and then fixed below the light guide plate, thus facilitating not only transportation but also assembly of the backlight module. 
         [0023]      FIGS. 1 and 2  show the backlight module  100  of the first embodiment of the present invention. As shown in the figures, the backlight module  100  of the present invention includes a light collection system (not shown in the diagram) used for collecting sunlight, a light guide plate  13 , an optical fiber connector  12 , and a plurality of optical fibers  11 . Wherein the plurality of optical fibers  11  are parallel to each other and coplanar and fixed side by side to the back of the light guide plate  13  (the lower surface of the light guide plate  13  as shown in the figures), and the light emitting end of each optical fiber  11  is parallel to and coplanar (flush) with the light incident end of the light guide plate  13  (the right end face of the light guide plate  13  as shown in the figures). The optical fiber connector  12  in this embodiment is an isosceles right triangle prism  12 , whose right angle is opposite to a mirror having an upper portion abutting against the light incident end of the light guide plate  13  and a lower portion abutting against the light emitting end of the optical fiber  11 , used for transferring the sunlight emitted from the light emitting end of the optical fiber  11  to the light guide plate  13  through the light incident end of the light guide plate  13 . 
         [0024]    In this embodiment, the light guide plate  13  is made of an acrylic sheet, on the undersurface of which are printed light guide spots by the UV screen printing technology. The materials used for printing have a very high reflectivity and zero absorbance. This acrylic sheet is used for absorbing the light emitting from the light source, making the light stop over on the surface of the acrylic sheet; when the light irradiates each of the light guide spots, the reflected light will be diffused to different directions, and undermine the reflection conditions before being emitted from the front of the light guide plate. Through a variety of light guide spots of different density and size, the light guide plate  13  can be made to emit light evenly. In addition, for further improving the visual angle and uniformity of brightness of the backlight module  100 , at least one optical film  14  can be fitted on the light emitting surface of the light guide plate  13  (the upper surface of the light guide plate  13  in the figures), with the optical film  14  laminated on the upper surface of the light guide plate  13 . 
         [0025]    In this embodiment, the isosceles right triangle prism  12  is made of glass, polymethyl methacrylate or engineering plastics having a high refractive index, and has a refractive index in the range of 1.4-1.6, enabling sunlight to be transferred efficiently to the light guide plate  13  based on the reflection principle; the isosceles right triangle prism  12  has an edge length greater than or equal to the width of the light guide plate  13 , so as to prevent leakage of light. 
         [0026]    In the specific implementation process, the light collection system converges and guides sunlight into the plurality of optical fibers  11 , which project the sunlight transferred by them approximately perpendicularly onto the right angle mirror of the isosceles right triangle prism  12  (the mirror opposite to the right angle); the isosceles right triangle prism  12  then reflects the incident sunlight twice before transferring it approximately perpendicularly to the light incident end of the light guide plate  13  that, by making use of the high light transmission rate of the light guide spots, makes the light source refracted into a surface light source that is to be presented to a customer, and then the optical film  14  is used for making the brightness of the backlight module  100  more uniform and the visual angle thereof more appropriate. 
         [0027]      FIG. 3  shows the backlight module  200  of the second embodiment of the present invention. As shown in the figure, the backlight module  200  of the present invention includes a light collection system, a light guide plate  23 , an optical fiber connector  22 , and a plurality of optical fibers  21 . Wherein the light collection system, the light guide plate  23  and the plurality of optical fibers  21  are completely the same with the light collection system, the light guide plate  13  and the plurality of optical fibers  11  of the backlight module  100  of the above first embodiment in features and assembly methods theirselves. The optical fiber connector  22  in this embodiment is a half-cylindrical lens  22 , whose flat mirror has an upper portion abutting against the light incident end of the light guide plate  23  and a lower portion abutting against the light emitting end of the optical fiber  21 , used for transferring the sunlight emitted from the light emitting end of the optical fiber  21  to the light guide plate  23  through the light incident end of the light guide plate  23 , so as to prevent leakage of light. 
         [0028]    In this embodiment, the specific structure of the light guide plate  23  is the same with the light guide plate  13  of the first embodiment; in addition, for further improving the visual angle and uniformity of brightness of the backlight module  200 , the light guide plate  23  can be provided on its light emitting surface (the upper surface) with at least one optical film  24  identical to the optical film  14  of the above first embodiment, with the optical film  24  laminated on the upper surface of the light guide plate  23 . 
         [0029]    In this embodiment, the half-cylindrical lens  22  is made of glass, polymethyl methacrylate or engineering plastics having a high refractive index, and has a refractive index in the range of 1.4-1.6, enabling sunlight to be transferred efficiently to the light guide plate  23  based on the reflection principle; the specific light path of light in the half-cylindrical lens  22  is as shown in  FIG. 3 , with the length of the half-cylindrical lens  22  greater than or equal to the width of the light guide plate  23 , so as to prevent leakage of light. 
         [0030]    In the specific implementation process, the light collection system converges sunlight into the plurality of optical fibers  21 , which project the sunlight transferred by them approximately perpendicularly onto the flat mirror of the half-cylindrical lens  22 , which then reflects the incident sunlight twice before transferring it approximately perpendicularly to the light incident end of the light guide plate  23  that, by making use of the high light transmission rate of the light guide spots, makes the light refracted into a surface light source that is to be presented to a customer, and then the optical film  24  is used for making the brightness of the backlight module  200  more uniform and the visual angle thereof more appropriate. 
         [0031]      FIG. 4  shows the backlight module  300  of the third embodiment of the present invention. As shown in the figure, the backlight module  300  of the present invention includes a light collection system, a light guide plate  33 , an optical fiber connector  32 , and a plurality of optical fibers  31 . Wherein the light collection system, the light guide plate  33  and the plurality of optical fibers  31  are completely the same with the light collection system, the light guide plate  13  and the plurality of optical fibers  11  of the backlight module  100  of the above first embodiment in features and assembly methods theirselves. The optical fiber connector  32  in this embodiment is a mirror group  32 , which includes a plane mirror  321  and a plane mirror  322  forming an angle of 90 degrees therebetween (perpendicular to each other), the plane mirror  321  abutting against the light emitting end of the optical fiber  31 , the plane mirror  322  abutting against the light incident end of the light guide plate  33 , with the direction of the received sunlight changed by 180 degrees after two reflections, used for reversely transferring the sunlight emitted from the light emitting end of the optical fiber  31  to the light guide plate  33  through the light incident end of the light guide plate  33 . 
         [0032]    In this embodiment, the specific structure of the light guide plate  33  is the same with the light guide plate  13  of the first embodiment; in addition, for further improving uniformity of the visual angle and brightness of the backlight module  300 , the light guide plate  33  can be provided on its light emitting surface (the upper surface) with at least one optical film  34  identical to the optical film  14  of the above first embodiment, with the optical film  34  laminated on the upper surface of the light guide plate  33 . 
         [0033]    In this embodiment, the plane mirrors  321  and  322  included in the mirror group  32  are hollow mirrors, and can totally reflect the light transferred to the mirror, with the length of the mirror group  32  greater than or equal to the width of the light guide plate  33 , so as to prevent leakage of light. 
         [0034]    In the specific implementation process, the light collection system converges sunlight into the plurality of optical fibers  31 , which project the sunlight transferred by them onto the plane mirror  321  at an angle of 45 degrees; then the plane mirror  321  reflects the light at an angle of 45 degrees onto the plane mirror  322 , which reflects the light at an angle of 45 degrees onto the light incident end of the light guide plate  33 , with the light reflected onto the light incident end of the light guide plate  33  approximately perpendicular to the end surface of this light incident end; the light guide plate  33 , by making use of the high light transmission rate of the light guide spots, makes the light source refracted into a surface light source that is to be presented to a customer, and then the optical film  34  is used for making the brightness of the backlight module  300  more uniform and the visual angle thereof more appropriate. 
         [0035]    All the above are only the preferred examples of the present invention, and do not limit the present invention. For those skilled in the art, the present invention can have a variety of amendment and change. Any amendment, equivalent replacement, improvement, etc. within the spirit and principle of the present invention shall fall within the protection scope of claims of the present invention.