Abstract:
A light deflection film is provided, which includes an incident surface including a plurality of first prism structures, and an emission surface including a plurality of second prism structures. The first prism structure includes a first surface and a second surface, a first angle between the first surface and an X-axis is 0 to 20 degree, a second angle between the second surface and a Y-axis is 5 to 60 degree. The second prism structure comprises a third surface and a fourth surface, a third angle between the third surface and the X-axis is 0 to 20 degree, a fourth angle between the fourth surface and the Y-axis is 5 to 60 degree. Thus, as implemented in windows, the light deflection film may guide partial sunlight to a ceiling to increase ambient brightness, reduce the usage quantity of illumination devices, and avoid glare.

Description:
CROSS-REFERENCE STATEMENT 
       [0001]    This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 101129620 filed in Taiwan, R.O.C. on Aug. 15, 2012, the entire contents of which are hereby incorporated by reference. 
       TECHNICAL FIELD 
       [0002]    The disclosure relates to an optical film, and more particularly to an optical film for deflecting light. 
       BACKGROUND 
       [0003]    With the development of technology and economic, life quality people request is getting higher, and that may cause crude oil is getting less. Over the years, various green energy technologies are developed because of higher environment protection sense, and energy conservation in the illumination art is one of the important targets thereof. It is necessary at night for illumination apparatus to provide light, so is it at daytime. Thus, indirect illumination technology is developed to guide outdoor sunlight to be indirect illumination light, so as to meet the request of energy conservation. 
         [0004]    In the present art, some skills, e.g. reflection film and prism structure element, are developed to carry out above indirect illumination purpose. Specifically, the reflection film is used to reflect outdoor sunlight to the indoor ceiling so as to provide indirect illumination for indoor space. However, such a reflection film may block outdoor scenery. 
         [0005]    The prism structure element is used to guide outdoor sunlight to indoor ceiling and has flat regions which outdoor scenery may not be blocked by. However, the partial sunlight guided by prism structure element may cause glare. Therefore, an optical film, which guides sunlight from outdoor space to indoor space and does not cause glare, is developed. 
       SUMMARY 
       [0006]    The disclosure provides one embodiment which relates to a light deflection film, which is adapted to receive light and comprises an incident surface and an emission surface. The incident surface comprises a plurality of first prism structures, the first prism structure comprises a first surface and a second surface, a first angle between the first surface and an X-axis is 0 to 20 degree, a second angle between the second surface and a Y-axis is 5 to 60 degree. The emission surface comprises a plurality of second prism structures, the second prism structure comprises a third surface and a fourth surface, a third angle between the third surface and the X-axis is 0 to 20 degree, and a fourth angle between the fourth surface and the Y-axis is 5 to 60 degree. Light is emitted out of the emission surface after penetrating into the light deflection film from the incident surface. 
         [0007]    The disclosure provides one embodiment which relates to a light deflection film, which is adapted to receive light and comprises a first light guiding plate, a second light guiding plate and an air layer. The first light guiding plate comprises an emission surface and a first structure surface comprising a plurality of first prism structures. The first prism structure comprises a first surface and a second surface, a first angle between the first surface and an X-axis is 0 to 15 degree, and a second angle between the second surface and a Y-axis is 5 to 45 degree. The second light guiding plate comprises an emission surface and a second structure surface comprising a plurality of second prism structures. The second prism structure comprises a third surface and a fourth surface, a third angle between the third surface and the X-axis is 0 to 15 degree, and a fourth angle between the fourth surface and the Y-axis is 5 to 45 degree. The air layer is disposed between the first structure surface and the second structure surface. Light penetrates into the light deflection film from the incident surface and emits out of the emission surface. 
         [0008]    For purposes of summarizing, some aspects, advantages and features of some embodiments of the disclosure have been described in this summary. Not necessarily all of (or any of) these summarized aspects, advantages or features will be embodied in any particular embodiment of the disclosure. Some of these summarized aspects, advantages and features and other aspects, advantages and features may become more fully apparent from the following detailed description and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the present disclosure, and wherein: 
           [0010]      FIG. 1  is a sectional schematic diagram of a profile structure of a light deflection film according to a first embodiment of the disclosure; 
           [0011]      FIG. 2A-FIG .  2 J are schematic diagrams of light distribution curve of the light deflection film of  FIG. 1  which light penetrates into by elevation angles of 5, 15, 25, 35, 45, 55, 65, 75, 80 and 85 degree respectively; 
           [0012]      FIG. 3  is a schematic diagram of power percentage curves of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction when light penetrates into the light deflection film of  FIG. 1  by elevation angles of 5 to 85 degree respectively; 
           [0013]      FIG. 4A  is a sectional schematic diagram of a profile structure of a light deflection film according to a second embodiment of the disclosure; 
           [0014]      FIG. 4B  and  FIG. 4C  are schematic diagrams of power percentage curve of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction when light penetrates into the light deflection film of  FIG. 4A  by elevation angles of 5 to 85 degree respectively; 
           [0015]      FIG. 5  is a sectional schematic diagram of a profile structure of a light deflection film according to a third embodiment of the disclosure; 
           [0016]      FIG. 6A-FIG .  6 H are schematic diagrams of light distribution curve of the light deflection film of  FIG. 5  which light penetrates into by elevation angles of 10, 20, 30, 40, 50, 60, 70 and 80 degree respectively; 
           [0017]      FIG. 6I  is a schematic diagram of power percentage curves of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction when light penetrates into the light deflection film of  FIG. 5  by elevation angles of 5 to 85 degree respectively; 
           [0018]      FIG. 6J  is a schematic diagram of a simulate power percentage curve and a measured power percentage curve of the deflected light in a ceiling direction; 
           [0019]      FIG. 7A  is a sectional schematic diagram of a profile structure of a light deflection film according to a fourth embodiment of the disclosure; 
           [0020]      FIG. 7B  and  FIG. 7C  are schematic diagrams of power percentage curve of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction when light penetrates into the light deflection film of  FIG. 7A  by elevation angles of 5 to 85 degree respectively; 
           [0021]      FIG. 8  is a sectional schematic diagram of a profile structure of a light deflection film according to a fifth embodiment of the disclosure; 
           [0022]      FIG. 9  is a sectional schematic diagram of a profile structure of a light deflection film according to a sixth embodiment of the disclosure; 
           [0023]      FIG. 10A-FIG .  10 H are schematic diagrams of light distribution curve of the light deflection film of  FIG. 9  which light penetrates into by elevation angles of 10, 20, 30, 40, 50, 60, 70 and 80 degree respectively; 
           [0024]      FIG. 10I  is a schematic diagram of power percentage curves of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction when light penetrates into the light deflection film of  FIG. 9A  by different elevation angles respectively; 
           [0025]      FIG. 11  is a sectional schematic diagram of a profile structure of a light deflection film according to a seventh embodiment of the disclosure; 
           [0026]      FIG. 12A-FIG .  12 H are schematic diagrams of light distribution curve of the light deflection film of  FIG. 11  which light penetrates into by elevation angles of 10, 20, 30, 40, 50, 60, 70 and 80 degree respectively; 
           [0027]      FIG. 12I  is a schematic diagram of power percentage curves of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction when light penetrates into the light deflection film of  FIG. 11  by different elevation angles respectively; 
           [0028]      FIG. 13  is a sectional schematic diagram of a profile structure of a light deflection film according to an eighth embodiment of the disclosure; 
           [0029]      FIG. 14A-FIG .  14 H are schematic diagrams of light distribution curve of the light deflection film of  FIG. 13  which light penetrates into by elevation angles of 10, 20, 30, 40, 50, 60, 70 and 80 degree respectively; 
           [0030]      FIG. 14I  is a schematic diagram of power percentage curves of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction when light penetrates into the light deflection film of  FIG. 13  by different elevation angles respectively; and 
           [0031]      FIG. 15  is a sectional schematic diagram of a profile structure of a light deflection film according to a ninth embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    The detailed features and advantages of the disclosure are described below in great detail through the following embodiments, the content of which is sufficient for those of ordinary skill in the art to understand the technical content of the disclosure and to implement the disclosure accordingly. Based upon the content of the specification, the claims, and the drawings, those of ordinary skill in the art can easily understand the relevant objectives and advantages of the disclosure. 
         [0033]    For explanation of the disclosure, one embodiment of a light deflection film implemented in a window is taken for illustration hereinafter. 
         [0034]      FIG. 1  illustrates a sectional schematic diagram of a profile structure of a light deflection film according to a first embodiment of the disclosure. The light deflection film  10  includes an incident surface  11  and an emission surface  12 . Light  1  penetrates into the light deflection film  10  from the incident surface  11  by an elevation angle a. 
         [0035]    The incident surface  11  includes a plurality of first prism structures  13  arranged at the incident surface  11  along a Y-axis. The emission surface  12  includes a plurality of second prism structures  14  arranged at the emission surface  12  along the Y-axis. In this embodiment, only three first prism structures  13  and three second prism structures  14  are taken in  FIG. 1  for illustration purpose. 
         [0036]    Each first prism structure  13  includes a first surface  131  and a second surface  135 . The first surface  131  and the second surface  135  meet to form a first vertex  133 . A distance D 1  between two adjacent first vertexes  133  is from 1 micrometer to 20 millimeter. The first surface  131  and an X-axis meet to form a first angle θ1. The second surface  135  and the Y-axis meet to form a second angle θ2. The first angle θ1 may be, but not limit to, from 0 to 20 degree. In one embodiment, the first angle θ1 is from 0 to 15 degree. In another embodiment, the first angle θ1 is from 0 to 10 degree. The second angle θ2 may be, but not limit to, from 5 to 35 degree. In one embodiment, the second angle θ2 is from 15 to 30 degree. 
         [0037]    Each second prism structure  14  includes a third surface  141  and a fourth surface  145 . The third surface  141  and the fourth surface  145  meet to form a second vertex  143 . A distance D 2  between two adjacent second vertexes  143  is from 1 micrometer to 20 millimeter. The third surface  141  and the X-axis meet to form a third angle θ3. The fourth surface  145  and the Y-axis meet to form a fourth angle θ4. The third angle θ3 may be, but not limit to, from 0 to 20 degree. In one embodiment, the third angle θ3 is from 0 to 15 degree. In another embodiment, the third angle θ3 is from 0 to 10 degree. The fourth angle θ4 may be, but not limit to, from 20 to 60 degree. In one embodiment, the fourth angle θ4 is from 25 to 45 degree. 
         [0038]    Besides, the range of the second angle θ2 and the fourth angle θ4 may be exchanged. In other word, both the second angle θ2 and the fourth angle θ4 may be from 5 to 60 degree in accordance with application requests. 
         [0039]    One embodiment of the light deflection film  10  is provided shown as  FIG. 2A  to  FIG. 2J  and  FIG. 3 .  FIG. 2A  to  FIG. 2J  illustrate schematic diagrams of light distribution curve of the light deflection film of  FIG. 1  which light penetrates into by elevation angles of 5, 15, 25, 35, 45, 55, 65, 75, 80 and 85 degree respectively.  FIG. 3  illustrates a schematic diagram of power percentage curves of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction when light penetrates into the light deflection film of  FIG. 1  by elevation angles of 5 to 85 degree respectively. 
         [0040]    In this embodiment, the distances D 1  and D 2  are 50 micrometer. The first angle θ1 is 3 degree. The second angle θ2 is 27 degree. The third angle θ3 is 3 degree. The fourth angle θ4 is 28 degree. 
         [0041]    Center P indicates the position where Light  1  penetrates into the light deflection film  10 . Each concentric arc indicates the light intensity which light  1  penetrates the light deflection film  10  from the outdoor space WO to the indoor space WI. Each radial line indicates the angle between light and the normal line (line of 0 degree) while light  1  penetrates the light deflection film  10 , and a regular interval between two adjacent radial lines is 10 degree. The range from +90 degree through 0 degree to −90 degree indicates indoor space WI. The range from +90 degree through ±180 degree to −90 degree indicates outdoor space WO. The range from 0 degree to +90 degree indicates that light  1  is deflected toward the ceiling direction H (upper deflection) after penetrating the light deflection film  10 . The range from −90 degree to 0 degree indicates that light  1  is deflected toward the floor direction G (down deflection) after penetrating the light deflection film  10 . 
         [0042]    In  FIG. 3 , the solid line curve with squares indicates the power percentage of the light in the ceiling direction H accounting for light  1  penetrating the light deflection film  10 , the solid line curve with triangles indicates the power percentage of the light in the floor direction G accounting for light  1  penetrating the light deflection film  10 , and the dotted line curve with rhombuses indicates the transmittance of light  1  penetrating the light deflection film  10 . The sum of the power percentage of the light in the ceiling direction H and in the floor direction G is the power percentage of light  1  penetrating the light deflection film  10 . 
         [0043]    The elevation angle α larger than 55 degree occurs just about at noon, where it is not necessary to use any illumination device in the indoor space WI. Moreover, the power percentage of the light penetrating the light deflection film  10  may be not very large if the elevation angle α is larger than 55 degree. This may avoid increasing the temperature of the indoor space WI. Moreover, the power percentage of the light penetrating the light deflection film  10  is about 80 percent if the elevation angle α is 80 degree, and the position of the light shooting into the indoor space WI may be more closed to the light deflection film  10  as shown as  FIG. 21 . Thus, glare may be avoided. 
         [0044]    Referring to  FIG. 4A , the difference between the first and second embodiments is that the position of the first vertex  133  of the first prism structure  13  and the position of the second vertex  143  of the second prism structure  14  are at different levels at Y axis in the second embodiment. More particularly, as compared with the position of each first prism structure  13  at the Y-axis, the position of each second prism structure  14  is shifted by a distance D 3  at the emission surface  12  along Y axis. The distance D 3  is the minimum height difference between the first vertex  133  and the second vertex  143 . Other conditions of the second embodiment are equal to those of the first embodiment. Two embodiments of the light deflection film  10  of  FIG. 4A  are described in  FIG. 4B  and  FIG. 4C . 
         [0045]    In one embodiment, the first angle θ1 is 3 degree, the second angle θ2 is 27 degree, the third angle θ3 is 3 degree, the fourth angle θ4 is 28 degree, and the distance D 3  is 17 micrometer. When light  1  penetrates into such a light deflection film  10  of  FIG. 4A  by elevation angles of 5 to 85 degree, the power percentage curves of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction are shown in  FIG. 4B . 
         [0046]    In another embodiment, the first angle θ1 is 3 degree, the second angle θ2 is 27 degree, the third angle θ3 is 3 degree, the fourth angle θ4 is 28 degree, and the distance D 3  is 34 micrometer. When light  1  penetrates into such a light deflection film  10  of  FIG. 4A  by elevation angles of 5 to 85 degree respectively, the power percentage curves of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction are shown in  FIG. 4C . 
         [0047]    According to  FIG. 3 ,  FIG. 4B  and  FIG. 4C , if the shape and the angles of each first prism structure  13  and of each second prism structure  14  in  FIG. 1  are equal to those in  FIG. 4A , it may not affect the efficiency of the light deflection film  10  guiding light  1  into the ceiling in the indoor space WI too much that the emission surface  12  is shifted by the distances D 3  as compared with the incident surface  11 . 
         [0048]    Referring  FIG. 5 , the light deflection film  20  of the third embodiment includes a first light guiding plate  1 D, a second light guiding plate  2 D and a transparent plate ST. The first light guiding plate  1 D includes an incident surface  21  and a first flat surface  25 . The incident surface  21  is opposite to the first flat surface  25 . The second light guiding plate  2 D includes an emission surface  22  and a second flat surface  26 . The transparent plate ST is disposed between the first flat surface  25  and the second flat surface  26 . Light  1  penetrates into the light deflection film  20  from the incident surface  21  by an elevation angle α. 
         [0049]    The incident surface  21  includes a plurality of first prism structures  23  arranged at the incident surface  21  along a Y-axis. The emission surface  22  includes a plurality of second prism structures  24  arranged at the emission surface  22  along the Y-axis. 
         [0050]    Each first prism structure  23  includes a first surface  231  and a second surface  235 . The first surface  231  and the second surface  235  meet to form a first vertex  233 . A distance S 1  between two adjacent first vertexes  233  is from 1 micrometer to 20 millimeter. The first surface  231  and the X-axis meet to form a first angle θ1. The second surface  235  and the Y-axis meet to form a second angle θ2. The first angle θ1 may be, but not limit to, from 0 to 20 degree. In one embodiment, the first angle θ1 is from 0 to 15 degree. In another embodiment, the first angle θ1 is from 0 to 10 degree. The second angle θ2 may be, but not limit to, from 5 to 35 degree. In one embodiment, the second angle θ2 is from 15 to 30 degree. 
         [0051]    Each second prism structure  24  includes a third surface  241  and a fourth surface  245 . The third surface  241  and the fourth surface  245  meet to form a second vertex  243 . A distance S 2  between two adjacent second vertexes  243  is from 1 micrometer to 20 millimeter. The third surface  241  and the X-axis meet to form a third angle θ3. The fourth surface  245  and the Y-axis meet to form a fourth angle θ4. The third angle θ3 may be, but not limit to, from 0 to 20 degree. In one embodiment, the third angle θ3 is from 0 to 15 degree. In another embodiment, the third angle θ3 is from 0 to 10 degree. The fourth angle θ4 may be, but not limit to, from 20 to 60 degree. In one embodiment, the fourth angle θ4 is from 25 to 45 degree. 
         [0052]    Besides, the range of the second angle θ2 and the range of the fourth angle θ4 may be exchanged. In other word, both the second angle θ2 and the fourth angle θ4 may be from 5 to 60 degree in accordance with application requests. 
         [0053]    Moreover, the amount of the first prism structures  23 , and of the second prism structures  24  in  FIG. 5  are taken for illustration purpose and should not limit the scope of the disclosure. The first light guiding plate  1 D and the second light guiding plate  2 D may be made of UV glue. The transparent substrate ST may be made of polyethylene terephthalate (PET). The material of the first light guiding plate  1 D, of the second light guiding plate  2 D, and of the transparent substrate ST may be designed according to application requests and should not limit the scope of the disclosure. 
         [0054]    In one embodiment, a metal die (not shown) and the skill of roll forming are used to perform UV curing. The first prism structures  23  and the second prism structures  24  on the metal die are transferred to the transparent substrate ST. 
         [0055]    Referring to  FIG. 6A  to  FIG. 6J , one embodiment based on the light deflection film  20  of  FIG. 5  is provided. The distances S 1  and S 2  are 50 micrometer. The first angle θ1 is 2 degree. The second angle θ2 is 24 degree. The third angle θ3 is 2 degree. The fourth angle θ4 is 36 degree. The first light guiding plate  1 D and the second light guiding plate  2 D are made of UV glue. The transparent substrate ST is made of PET. 
         [0056]    While Light  1  penetrates into the light deflection film  20  by different elevation angles α, the power percentages of the reflected light, the power percentages of the penetrating light, the power percentages of the light in the ceiling direction H (Upper Deflection Rate), and the power percentages of the light in the floor direction G (Down Defection Rate) are shown in Table 1. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                 Upper 
                 Down 
               
               
                 α 
                 Reflectance 
                 Transmittance 
                 Deflection 
                 Deflection 
               
               
                 (deg.) 
                 (%) 
                 (%) 
                 Rate (%) 
                 Rate (%) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 33.44 
                 66.56 
                 48.31 
                 18.25 
               
               
                 20 
                 23.87 
                 76.13 
                 58.46 
                 17.67 
               
               
                 30 
                 28.74 
                 71.26 
                 53.57 
                 17.69 
               
               
                 40 
                 40.27 
                 59.73 
                 42.73 
                 17 
               
               
                 50 
                 58.34 
                 41.66 
                 2.285 
                 39.375 
               
               
                 60 
                 58.85 
                 41.15 
                 3.65 
                 37.5 
               
               
                 70 
                 88.03 
                 11.97 
                 4.977 
                 6.993 
               
               
                 80 
                 80.71 
                 19.29 
                 9.343 
                 9.947 
               
               
                   
               
             
          
         
       
     
         [0057]    In this embodiment, the schematic diagrams of light distribution curve based on the elevation angles of 10, 20, 30, 40, 50, 60, 70 and 80 degree are respectively shown in  FIG. 6A  to  FIG. 6H , and the power percentages of the light in the ceiling direction H and in the floor direction G are shown in  FIG. 6I . If the elevation angle α is 50 degree, the light entering in to the indoor space WI is almost emitted out of the second light guiding plate  2 D horizontally. If the elevation angle α is 85 degree, the light in the indoor space WI is almost deflected toward the floor near the window. The measure and simulation results of the power percentages of the light in the ceiling direction H are shown in  FIG. 6J . 
         [0058]    Referring to  FIG. 7A , the difference between the third and fourth embodiments is that the position of the first vertex  233  of the first prism structure and the position of the second vertex  243  of the second prism structure are at different levels at Y axis in the fourth embodiment. More particularly, as compared with the position of each first prism structure at the Y-axis, the position of each second prism structure is shifted by a distance S 3  at the emission surface  22  along Y axis. The distance S 3  is the minimum height difference between the first vertex  233  and the second vertex  243 . Other conditions of the fourth embodiment are equal to those of the third embodiment. The first light guiding plate  1 D and the second light guiding plate  2 D are made of UV glue. The transparent substrate ST is made of PET. Two embodiments of the light deflection film  20  of  FIG. 7A  are described in  FIG. 7B  and  FIG. 7C . 
         [0059]    In one embodiment, the first angle θ1 is 2 degree, the second angle θ2 is 24 degree, the third angle θ3 is 2 degree, the fourth angle θ4 is 36 degree, and the distance S 3  is 17 micrometer. When light  1  penetrates into such a light deflection film  20  of  FIG. 7A  by an elevation angle α of 5 to 85 degree respectively, the power percentage curves of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction are shown in  FIG. 7B . 
         [0060]    In another embodiment, the first angle θ1 is 2 degree, the second angle θ2 is 24 degree, the third angle θ3 is 2 degree, the fourth angle θ4 is 36 degree, and the distance S 3  is 34 micrometer. When light  1  penetrates into such a light deflection film  20  of FIG.  7 A by elevation angles of 5 to 85 degree respectively, the power percentage curves of the complete emitted light, of the deflected light in a ceiling direction, and of the deflected light in a floor direction are shown in  FIG. 7C . 
         [0061]    According to  FIG. 6I ,  FIG. 7B  and  FIG. 7C , if the shapes and the angles of each first prism structure  23  and of each second prism structure  24  in  FIG. 5  are equal to those in  FIG. 7A , it may not affect the efficiency of the light deflection film  20  guiding light  1  into the ceiling in the indoor space WI too much that the emission surface  22  is shifted by various distances S 3  as compared with the incident surface  21 . 
         [0062]      FIG. 8  illustrates a sectional schematic diagram of a profile structure of a light deflection film according to a fifth embodiment of the disclosure. In this embodiment, beside the light deflection film  10 , the light deflection film  30  further includes a first protection layer  31  and a second protection layer  32 . The incident surface  11  is disposed between the emission surface  12  and the first protection layer  31 , and the emission surface  12  is disposed between the incident surface  11  and the second protection layer  32 . Thus, the abrasion between the first prism structures and the second prism structures may be avoided, and the dusts accumulating on the light deflection film  30  may be cleaned more easily. The first protection layer  31  and the second protection layer  32  may be made of glass or other transparent material with great wear-resisting. 
         [0063]      FIG. 9  illustrates a sectional schematic diagram of a profile structure of a light deflection film according to a sixth embodiment of the disclosure. The differences between the first and sixth embodiments are that a first arc angle R 1  is formed at each first vertex  433  and that a second arc angle R 2  is formed at each second vertex  443 . A distance D 1  is formed between two adjacent first vertexes  433 . A distance D 2  is formed between two adjacent second vertexes  443 . The radius of the first arc angle R 1  and the radius of the second arc angle R 2  are equal to or larger than 0 micrometer and are less than or equal to 15 millimeter. Light  1  penetrates into the light deflection film  40  from the incident surface  41  and is emitted out of the emission surface  42 . The definition of the angles of each prism structure is equal to that of the light deflection film  10  of the first embodiment. 
         [0064]    In one embodiment based on  FIG. 9 , the distances D 1  and D 2  are 50 micrometer, the first angle θ1 is 0 degree, the second angle θ2 is 25 degree, the third angle θ3 is 0 degree, the fourth angle θ4 is 40 degree, the radius of the first arc angle R 1  is 11 micrometer, the radius of the second arc angle R 2  is 15 millimeter. 
         [0065]    While Light  1  penetrates into the light deflection film  40  by different elevation angles α, the power percentages of the reflected light, the power percentages of the penetrating light, the power percentages of the light in the ceiling direction H (Upper Deflection Rate), and the power percentages of the light in the floor direction G (Down Defection Rate) are shown in Table 2. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                   
                 Upper 
                 Down 
               
               
                 α 
                 Reflectance 
                 Transmittance 
                 Deflection 
                 Deflection 
               
               
                 (deg.) 
                 (%) 
                 (%) 
                 Rate (%) 
                 Rate (%) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 28.6 
                 71.4 
                 30.82 
                 40.58 
               
               
                 20 
                 21.95 
                 78.05 
                 32.26 
                 45.79 
               
               
                 30 
                 14.67 
                 85.33 
                 23.76 
                 61.57 
               
               
                 40 
                 22.75 
                 77.25 
                 33.63 
                 43.62 
               
               
                 50 
                 40.35 
                 59.65 
                 8.948 
                 50.702 
               
               
                 60 
                 51.05 
                 48.95 
                 5.292 
                 43.658 
               
               
                 70 
                 54.46 
                 45.54 
                 4.347 
                 41.193 
               
               
                 80 
                 73.55 
                 26.45 
                 2.485 
                 23.965 
               
               
                   
               
             
          
         
       
     
         [0066]    In this embodiment, the schematic diagrams of light distribution curve based on the elevation angles of 10, 20, 30, 40, 50, 60, 70 and 80 degree are respectively shown in  FIG. 10A  to  FIG. 10H , and the power percentages of the light in the ceiling direction H and in the floor direction G are shown in  FIG. 10I . If the elevation angle α is 80 degree, the light in the indoor space WI is almost deflected toward the floor near the window. 
         [0067]    In another embodiment based on  FIG. 9 , the surfaces of at least one of each first prism structure  43  and each second prism structure  44  may satisfy the condition of a polynomial curve, or of an aspheric curve. 
         [0068]      FIG. 11  illustrates a sectional schematic diagram of a profile structure of a light deflection film according to a seventh embodiment of the disclosure. The differences between the first and seventh embodiments are that a third arc angle R 3  is formed at a first junction point  437  formed by two adjacent first prism structures meeting, and that a fourth arc angle R 4  is formed at a second junction point  447  formed by two adjacent second prism structures meeting. The radius of the third arc angle R 3  and the radius of the fourth arc angle R 4  are larger than or equal to 0 micrometer and are less than or equal to 15 millimeter. A distance D 1  is formed between two adjacent first vertexes  533 . A distance D 2  is formed between two adjacent second vertexes  543 . The angles of each prism structure are equal to those of the light deflection film  10  of the first embodiment. 
         [0069]    Referring to  FIG. 12A  to  FIG. 12I , one embodiment based on the light deflection film  50  of  FIG. 11  is provided. The distances D 1  and D 2  are 50 micrometer. The first angle θ1 is 0 degree. The second angle θ2 is 25 degree. The third angle θ3 is 0 degree. The fourth angle θ4 is 40 degree. The radius of the third arc angle R 3  is 0 micrometer. The radius of the fourth arc angle R 4  is 15 millimeter. 
         [0070]    While Light  1  penetrates into the light deflection film  50  by different elevation angles α, the power percentages of the reflected light, the power percentages of the penetrating light, the power percentages of the light in the ceiling direction H (Upper Deflection Rate), and the power percentages of the light in the floor direction G (Down Defection Rate) are shown in Table 3. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                   
                 Upper 
                 Lower 
               
               
                 α 
                 Reflectance 
                 Transmittance 
                 Deflection 
                 Deflection 
               
               
                 (deg.) 
                 (%) 
                 (%) 
                 Rate (%) 
                 Rate (%) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 48.95 
                 51.05 
                 23.5 
                 27.55 
               
               
                 20 
                 20.05 
                 79.95 
                 38.64 
                 41.31 
               
               
                 30 
                 21.01 
                 78.99 
                 35.36 
                 43.63 
               
               
                 40 
                 32.35 
                 67.65 
                 32.95 
                 34.7 
               
               
                 50 
                 45.86 
                 54.14 
                 15.29 
                 38.85 
               
               
                 60 
                 35.93 
                 64.07 
                 8.405 
                 55.665 
               
               
                 70 
                 68.82 
                 31.18 
                 7.394 
                 23.786 
               
               
                 80 
                 10.95 
                 89.05 
                 3.547 
                 85.503 
               
               
                   
               
             
          
         
       
     
         [0071]    In this embodiment, the schematic diagrams of light distribution curve based on the elevation angles of 10, 20, 30, 40, 50, 60, 70 and 80 degree are respectively shown in  FIG. 12A  to  FIG. 12H , and the power percentages of the light in the ceiling direction H and in the floor direction G are shown in  FIG. 12I . If the elevation angle α is 80 degree, the light in the indoor space WI is almost deflected toward the floor near the window. 
         [0072]      FIG. 13  illustrates a sectional schematic diagram of a profile structure of a light deflection film according to an eighth embodiment of the disclosure. The incident surface  61  includes a plurality of first prism structures  63  arranged at the incident surface  61  along Y-axis. The emission surface  62  includes a plurality of second prism structures  64  arranged at the emission surface  62  along Y-axis. Three first prism structures  63  and three second prism structures  64  are taken in  FIG. 13  for illustration purpose hereinafter. 
         [0073]    Each first prism structure  63  includes a first surface  631  and a second surface  635 . The first surface  631  and the second surface  635  meet to form a first vertex  633 . A distance W 1  between two adjacent first vertexes  633  is from 1 micrometer to 20 millimeter. Each second prism structure  64  includes a third surface  641  and a fourth surface  645 . The third surface  641  and the fourth surface  645  meet to form a second vertex  643 . A distance W 2  between two adjacent second vertexes  643  is from 1 micrometer to 20 millimeter. The angles of each prism structure are equal to the light deflection film  10  of the first embodiment. 
         [0074]    Besides, the incident surface  61  further includes fifth surfaces  632 , and the emission surface  62  further includes sixth surfaces  642 . The fifth surface  632  is disposed between two adjacent first prism structures  63 . The fifth surface  632  respectively connects to the first surface  631  of one of the two adjacent first prism structures  63  and the second surface  635  of another one of the two adjacent first prism structures  63 . The length Q 1  of the fifth surface  632  is less than or equal to a half of the distance W 1 . The sixth surface  642  is disposed between two adjacent second prism structures  64 . The sixth surface  642  respectively connects to the third surface  641  of one of the two adjacent second prism structures  64  and the fourth surface  645  of another one of the two adjacent second prism structures  64 . The length Q 2  of the sixth surface  642  is less than or equal to a half of the distance W 2 . The penetrability of the light deflection film  60  is increased as the percentage of the length Q 1  in the distance W 1  and the percentage of the length Q 2  in the distance W 2  are higher. 
         [0075]    Referring to  FIG. 14A  to  FIG. 14I , one embodiment based on the light deflection film  60  of  FIG. 13  is provided. The distances W 1  and W 2  are 70 micrometer. The lengths Q 1  and Q 2  are 25 micrometer. The first angle θ1 is 0 degree. The second angle θ2 is 25 degree. The third angle θ3 is 0 degree. The fourth angle θ4 is 40 degree. 
         [0076]    While Light  1  penetrates into the light deflection film  60  by different elevation angles α, the power percentages of the reflected light, the power percentages of the penetrating light, the power percentages of the light in the ceiling direction H (Upper Deflection Rate), and the power percentages of the light in the floor direction G (Down Defection Rate) are shown in Table 4. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
               
                   
                   
                   
                 Upper 
                 Lower 
               
               
                 α 
                 Reflectance 
                 Transmittance 
                 Deflection 
                 Deflection 
               
               
                 (deg.) 
                 (%) 
                 (%) 
                 Rate (%) 
                 Rate (%) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 32.71 
                 67.29 
                 55.25 
                 12.04 
               
               
                 20 
                 22.08 
                 77.92 
                 39.83 
                 38.09 
               
               
                 30 
                 24.47 
                 75.53 
                 19.6 
                 55.93 
               
               
                 40 
                 31.44 
                 68.56 
                 29.83 
                 38.73 
               
               
                 50 
                 41.26 
                 58.74 
                 17.74 
                 41 
               
               
                 60 
                 37.3 
                 62.7 
                 3.885 
                 58.815 
               
               
                 70 
                 55.38 
                 44.62 
                 5.187 
                 39.433 
               
               
                 80 
                 59.36 
                 40.64 
                 5.767 
                 34.873 
               
               
                   
               
             
          
         
       
     
         [0077]    In this embodiment, the schematic diagrams of light distribution curve based on the elevation angles of 10, 20, 30, 40, 50, 60, 70 and 80 degree are respectively shown in  FIG. 14A  to  FIG. 14H , and the power percentages of the light in the ceiling direction H and in the floor direction G are shown in  FIG. 14I . If the elevation angle α is 80 degree, the light in the indoor space WI is almost deflected toward the floor near the window. 
         [0078]      FIG. 15  illustrates a sectional schematic diagram of a profile structure of a light deflection film according to a ninth embodiment of the disclosure. The light deflection film  70  includes a first light guiding plate  3 D and a second light guiding plate  4 D. An air layer AR fills the space between the first light guiding plate  3 D and the second light guiding plate  4 D so as to avoid which the dusts covering on the prism structures effects the guiding efficient. 
         [0079]    The first light guiding plate  3 D includes an incident surface  71  and a first structure surface  75 . The first light guiding plate  3 D includes a plurality of first prism structures. The second light guiding plate  4 D includes a second structure surface  76  and an emission surface  72 . The second structure surface  76  includes a plurality of second prism structures. The first structure surface  75  and the second structure surface  76  are opposite. Light  1 , in order, penetrates into the first light guiding plate  3 D from the incident surface  71 , is emitted out of the first structure surface  75 , penetrates the air layer AR, penetrates into the second light guiding plate  4 D from the second structure surface  76 , and is emitted out of the emission surface  72 . 
         [0080]    The definition of angles of prism structures is equal to the light deflection film  10  of the first embodiment. The ranges of the first angle θ5 to the fourth angle θ8 may differ from the ranges of the first angle θ1 to the fourth angle θ4 of the light deflection film 10 of the first embodiment. The first angle θ5 may be, but not limit to, from 0 to 15 degree. In one embodiment, the first angle θ5 is from 0 to 10 degree. The second angle θ6 may be, but not limit to, from 15 to 45 degree. In one embodiment, the second angle θ6 is from 25 to 35 degree. The third angle θ7 may be, but not limit to, from 0 to 15 degree. In one embodiment, the third angle is from 0 to 10 degree. The fourth angle θ8 may be, but not limit to, from 5 to 30 degree. In one embodiment, the fourth angle θ8 is from 15 to 25 degree. 
         [0081]    Besides, the ranges of the second angle θ6 and the fourth angle θ8 may be exchanged. In other word, the ranges of the second angle θ6 and the fourth angle θ8 are from 5 to 45 degree. 
         [0082]    By arranging the distance between two adjacent first vertexes, the distance between two adjacent second vertexes, the first angle, the second angle, the third angle and the fourth angle, incident light with an elevation angle larger than 55 degree is almost reflected by the light deflection film of the disclosure, and incident light with an elevation angle of from 0 to 45 degree is almost deflected upward by the light deflection film of the disclosure. By adding the first protection layer and the second protection layer, the first prism structures and the second prism structures may not be abraded, and the dusts on the light deflection film may be clean easily. Through the fifth surface and the sixth surface, outdoor scenery may be more observable. By forming the first arc angle and the second arc angle or forming third arc angle and the fourth arc angle, light is deflected upward the ceiling direction more uniformly. 
         [0083]    Thus, by designing the incident surface and the emission surface, the light deflection film selectively reflects light or deflected light upward, the sunlight guided into indoor space may become an indirect illumination and not become glare to human eyes, and the light deflection film may carry out the purpose of illumination energy conservation. 
         [0084]    The disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and region of equivalency of the claims are to be embraced within their scope.