Abstract:
A method of manufacturing a light refection film includes: preparing a precursor, the precursor includes white pigments and liquid UV (ultraviolet) curing material. The white pigments are evenly dispersed in the UV curing material, and a weight ratio of the white pigments and the UV curing material ranges from 20:80 to 38:62. Then the following step is providing a first base, and arranging a blocking part on the first base to limit a receiving area of the precursor. The precursor is thereafter dropped into the receiving area of the precursor. A second base is then brought to press the precursor, the precursor is cured by exposure UV to form the light reflection film, finally the first base, the second base, and the blocking part are removed to obtain the light reflection film. The present disclosure also provides a light reflection film obtained by the method.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The disclosure relates to a light reflection film, and also relates to a method of manufacturing the light reflection film. 
         [0003]    2. Discussion of Related Art 
         [0004]    Light reflection film is widely used in the field of light source and back light module. Generally, there are two ways to enhance a reflectivity of the light reflection film. In the first way, a special structure or an additional film may be formed on the light reflection film, which causes more costs. In the second way, the light reflection film is formed by plastic with white pigments mixed therein. The mixing of plastic and white pigments is treated by hot pressing and mould process and film-drawing process to form the light reflection film with a desired thickness. However, such method is complicated and time consuming. In addition, the lower content of the white pigments is benefit for the even distribution of the white pigments in the plastic, but is negative for the enhancement of the reflectivity of the light reflection film. For increasing a total content of the white pigments, the thickness of the light reflection film should be increased, which results in a high cost of raw materials and in contrary to the tendency of thinness. 
         [0005]    What is needed, therefore, is a light reflection film and a method of manufacturing the light reflection film, which can overcome the limitations described above. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present light reflection film and a method of manufacturing the light reflection film. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0007]      FIG. 1  is a cross-section view of a light reflection film in accordance with an exemplary embodiment of the present disclosure. 
           [0008]      FIG. 2  is a cross-section view of a first step of a method of manufacturing the light reflection film. 
           [0009]      FIG. 3  is a cross-section view of a second step of a method of manufacturing the light reflection film. 
           [0010]      FIG. 4  is a cross-section view of a third step of a method of manufacturing the light reflection film. 
           [0011]      FIG. 5  is a cross-section view of a fourth step of a method of manufacturing the light reflection film. 
           [0012]      FIG. 6  is a cross-section view of a fifth step of a method of manufacturing the light reflection film. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0013]    Referring to  FIG. 1 , a light reflection film  10  comprises UV (ultraviolet) curing material  101  and white pigments  102  contained in the UV curing material  101 . A thickness h of the light reflection film  10  is less than 0.2 mm, or is equal to 0.2 mm. 
         [0014]    The white pigments  102  are evenly dispersed in the UV curing material  101 . A weight ratio of the white pigments  102  and the UV curing material  101  ranges from 20:80 to 38:62. 
         [0015]    The UV curing material  101  is originally liquid without curing, and maintains solid after the UV curing material  101  absorbing enough ultraviolet. As shown in  FIG. 1 , the UV curing material  101  is solid. 
         [0016]    The UV curing material  101  includes a photoinitiator and a curable resin. After the UV curing material  101  absorbs ultraviolet, free radicals are generated from the photoinitiator, and a cross-linking reaction or a coplymerization is reacted between the free radicals and the curable resin, which results in the change of the UV curing material  101  from liquid to solid. 
         [0017]    The white pigments  101  are selected from a group consisting of ZnO (zinc oxide), ZnWO 4  (zinc tungstate), SiO 2  (silicon oxide), TiO 2  (titanium dioxide), CaCO 3  (calcium carbonate), CaSO 4  (calcium sulfate), BaSO 4  (barium sulfate) and Al 2 O 3  (aluminium oxide). An average particle diameter of the white pigments  102  ranges from about 0.1 μm to about 0.4 μm. 
         [0018]    In a preferred embodiment, the white pigments  102  are made of TiO 2 . The average particle diameter of the white pigments  102  is about 0.3 μm, and the weight ratio of the white pigments  102  and the UV curing material  101  is 35:65. 
         [0019]    In the present disclosure, a reflectivity of the light reflection film  10  is more than 98%, and the light reflection film  10  is as thin as no more than 0.2 mm. The light reflection film  10  is in conformity of a high reflectivity, a low thickness and a large content of the white pigments  102 . 
         [0020]    The present disclosure also provides a method of manufacturing the light reflection film  10 , and the method includes the following steps. 
         [0021]    Step 1 is, referring to  FIG. 2 , providing a precursor  10   a  ( FIG. 3 ) and providing a first base  31 , and arranging a blocking part  40  on a surface  311  of the first base  31  to construct a receiving area  50  for receiving the precursor  10   a  therein. The blocking part  40  is sticky, and arranged on the surface  311  of the first base  31 . The precursor  10   a  comprises UV curing material  101  and white pigments  102  mixed in the UV curing material  101 . The UV curing material  101  is liquid in the precursor  10   a . After the UV curing material  101  absorbs ultraviolet, the UV curing material  101  turns into solid and transparent. The white pigments  102  are evenly dispersed in the UV curing material  101 . 
         [0022]    In the process of mixing the white pigments  102  into the UV curing material  101 , ultrasonic wave or stirring can be used. A weight ratio of the white pigments  102  and the UV curing material  101  ranges from 20:80 to 38:62. The white pigments  102  can be selected from a group consisting of ZnO, ZnWO 4 , SiO 2 , TiO 2 , CaCO 3 , CaSO 4 , BaSO 4  and Al 2 O 3 . An average particle diameter of the white pigments  102  ranges from about 0.1 μm to about 0.4 μm. Some detailed embodiments of the precursor  10   a  are provided hereafter. 
         [0023]    A first exemplary embodiment: 
         [0024]    The weight ratio of the white pigments  102  and the UV curing material  101  is 20:80. The white pigments  102  are made of ZnO. The average particle diameter of the white pigments  102  is about 0.1 μm. 
         [0025]    A second exemplary embodiment: 
         [0026]    The weight ratio of the white pigments  102  and the UV curing material  101  is 28:72. The white pigments  102  are made of a mixture consisting of ZnO, ZnWO 4  and SiO 2 . A weight ratio of ZnO, ZnWO 4  and SiO 2  is 7:3:18. The average particle diameter of the white pigments  102  is about 0.2 μm. 
         [0027]    Before mixing the white pigments  102  and the UV curing material  101 , SiO 2  can be slivered or aluminized in surface treatment. 
         [0028]    A third exemplary embodiment: 
         [0029]    The weight ratio of the white pigments  102  and the UV curing material  101  is 30:70. The white pigments  102  are made of a mixture consisting of CaSO 4  and CaCO 3 . A weight ratio of CaSO 4  and CaCO 3  is 15:15. The average particle diameter of the white pigments  102  is about 0.4 μm. 
         [0030]    A fourth exemplary embodiment: 
         [0031]    The weight ratio of the white pigments  102  and the UV curing material  101  is 35:65. The white pigments  102  are made of TiO 2 . The average particle diameter of the white pigments  102  is about 0.3 μm. 
         [0032]    Preferably, the white pigments  102  consist of spherical TiO 2  particles. 
         [0033]    A fifth exemplary embodiment: 
         [0034]    The weight ratio of the white pigments  102  and the UV curing material  101  is 35:65. The white pigments  102  are made of a mixture consisting of TiO 2  and Al 2 O 3 . A weight ratio of TiO 2  and Al 2 O 3  is 30:5. The average particle diameter of the white pigments  102  is about 0.3 μm. 
         [0035]    A hardness of Al 2 O 3  is more than a hardness of TiO 2 . In this embodiment, before mixing the white pigments  102  and the UV curing material  101 , TiO 2  can be polished by Al 2 O 3  by a vibration polishing treatment to increase a surface evenness and smooth of TiO 2 , which is benefit for increasing a reflectivity of TiO 2 . 
         [0036]    A sixth exemplary embodiment: 
         [0037]    The weight ratio of the white pigments  102  and the UV curing material  101  is 38:62. The white pigments  102  are made of a mixture consisting of BaSO 4  and Al 2 O 3 . A weight ratio of BaSO 4  and Al 2 O 3  is 15:23. The average particle diameter of the white pigments  102  is about 0.2 μm. 
         [0038]    It is understood that the precursor  10   a  is not limited to the above embodiments. For example, the white pigments  102  can be made of organic material. 
         [0039]    Step 2 is, referring to  FIG. 3 , dropping the precursor  10   a  into the receiving area  50 . Since the UV curing material  101  includes resin, the precursor  10   a  comprising the UV curing material  101  and white pigments  102  has a certain viscosity and presents substantially a dome-shaped cross section after it has been dropped in the receiving area  50 . 
         [0040]    Step 3 is, referring to  FIG. 4 , providing a second base  32  to press the precursor  10   a  located on the first base  31  and to flatten the precursor  10   a . A distance between the first base  31  and the second base  32  depends on a pressure pressed on the first base  31  and the second base  32 . 
         [0041]    It is understood that the receiving area  50  is not fully closed (not shown). When pressing the second base  32  on the first base  31 , a redundant part of the precursor  10   a  can flow out of the receiving area  50 . 
         [0042]    Step 4 is, referring to  FIG. 5 , curing the precursor  10   a  to form the light reflection film  10 . It is understood that a thickness h of the light reflection film  10  is the distance between the first base  31  and the second base  32 . In this embodiment, the thickness h of the light reflection film  10  is less than or equal to 0.2 mm. 
         [0043]    The UV curing material  101  includes a photoinitiator and a curable resin. After the UV curing material  101  absorbs ultraviolet, free radicals are generated by the photoinitiator, and a cross-linking reaction or a coplymerization is reacted between the free radicals and the curable resin, resulting in the change of the UV curing material  101  from liquid to solid. 
         [0044]    It is understood that the first base  31  and the second base  32  are made of transparent material, and ultraviolet can pass through the first base  31  and the second base  32 . Further, in order to increase a curing efficiency, the first base  31  and the second base  32  are made of transparent glass, and the precursor  10   a  absorbs ultraviolet passing through the first base  31  and the second base  32  at the same time. 
         [0045]    Step 5 is, referring to  FIGS. 1 and 6 , removing the first base  31 , the second base  32 , and the blocking part  40 . It is understood that, in order to manufacture the light reflection film  10  with a proper size or a proper shape, a cutting step after the step 5, may be needed. 
         [0046]    Further, in order to easily remove the blocking part  40  from the first base  31  or the second base  32  in step 5, the blocking part  40  is preferably made of UV curing material. After absorbing ultraviolet, the blocking part  40  changes into solid and moves freely relative to the first and second bases  31 ,  32  and the light reflection film  10 . 
         [0047]    In the present disclosure, a reflectivity of the light reflection film  10  is more than 98%, and a thickness of the light reflection film  10  is less than or equal to 0.2 mm. The light reflection film  10  has a high content of the white pigments  102 , and the white pigments  102  are evenly dispersed in the light reflection film  10 . The light reflection film  10  is in conformity of a high reflectivity, a low thickness and a large content of the white pigments  102 . The method of manufacturing the light reflection film  10  avoids hot pressing and mould process and film-drawing process, thereby lowering the manufacturing cost.