Abstract:
The invention discloses a light-guiding plate and a manufacturing method thereof. The light-guiding plate includes a light-guiding substrate, a first shielding layer, and a second shielding layer. The light-guiding substrate has a first surface and a second surface opposite to the first surface. The first shielding layer is disposed on the first surface and includes a first light-transmitting portion. The second shielding layer is disposed on the second surface and includes a second light-transmitting portion. Thereby, light emitted from a light source could pass through the first light-transmitting portion, the light-guiding substrate, and the second light-transmitting portion, so that a light-halo phenomenon does not occur on the light-guiding plate.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a light-guiding plate and a manufacturing method thereof and, more particularly, to a light-guiding plate and a manufacturing method capable of overcoming the light-halo phenomenon. 
         [0003]    2. Description of the Prior Art 
         [0004]    Please refer to  FIG. 1 .  FIG. 1  is a sectional view illustrating a light-guiding plate and a light source in prior art. According to the embodiment, the light-guiding plate  1  comprises a light-guiding substrate  12 , a light-color ink layer  14  and a dark-color ink layer  16 . The light-color ink layer  14  is coated on the light-guiding substrate  12 , and the dark-color layer  16  is further coated on the light-color ink layer  14 . There is a hollow region among the light-color ink layer  14  and the dark-color ink layer  16  to form a light-transmitting region  18 . When the light source  2  is disposed below the light-guiding plate  1 , a light emitted by the light source  2  may pass through the light-transmitting region  18  and the light-guiding substrate  12  (the pattern of the light is shown in an arrowed dash line). As light-guiding substrate usually has a considerable thickness, the light scatters while passing through the light-guiding substrate  12 . Therefore, when the light is projected out through the light-guiding substrate  12 , the projecting region (shown as the mark L in  FIG. 1 ) is obviously larger than the intersectional surface of the light-transmitting region  18  so that the light-halo phenomenon is induced. 
         [0005]    When there is a pattern with some intensive stripes (e.g. small-sized letters) displayed on the light-transmitting region  18 , the stripes of the pattern can not be revealed, and even the instructing function is lost because of the light-halo phenomenon. In the trend of minimization of the electronic appliances, the light-guiding plate for instructing function is tending to have a smaller size, so does the instructing pattern thereon, which makes the light-halo phenomenon more irretrievable. 
       SUMMARY OF THE INVENTION 
       [0006]    A scope of the invention is to provide a light-guiding plate capable of overcoming the light-halo phenomenon. 
         [0007]    Another scope of the invention is to provide a manufacturing method of a light-guiding plate capable of overcoming the light-halo phenomenon. 
         [0008]    According to an embodiment, the light-guiding plate comprises a light-guiding substrate, a first shielding layer and a second shielding layer. The light-guiding substrate has a first surface and a second surface opposite to the first surface. The first shielding layer is disposed on the first surface and comprises a first light-transmitting portion. The second shielding layer is disposed on the second surface and comprises a second light-transmitting portion. Accordingly, a light emitted from a light source is capable of passing through the first light-transmitting portion, the light-guiding substrate and the second light-transmitting portion, so that a light-halo does not occur on the light-guiding plate while the light is projected out through the light-guiding substrate. 
         [0009]    The manufacturing method of the light-guiding plate of the invention comprises steps of: preparing a light-guiding substrate with a first surface and a second surface opposite to the first surface; forming a first shielding layer on the first surface, and the first shielding layer comprising a first light-transmitting portion; and forming a second shielding layer on the second surface, and the second shielding layer comprising a second light-transmitting portion. Accordingly, the light-guiding plate of the invention is formed. 
         [0010]    The advantage and spirit of the invention may be understood by the following recitations together with the appended drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE APPENDED DRAWINGS 
         [0011]      FIG. 1  is a sectional diagram illustrating a light-guiding plate and a light source in prior art. 
           [0012]      FIG. 2  is a sectional diagram illustrating a light-guiding plate and a light source according to an embodiment of the invention. 
           [0013]      FIG. 3  is a flowchart of manufacturing the light-guiding plate  3  shown in  FIG. 2 . 
           [0014]      FIG. 4  is a flowchart of manufacturing a light-guiding plate according to another embodiment of the invention. 
           [0015]      FIG. 5  is a schematic diagram illustrating the light-guiding plate  5  manufactured in  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Please refer to  FIG. 2 .  FIG. 2  is a sectional diagram illustrating a light-guiding plate and a light source according to an embodiment of the invention. According to the embodiment, the light-guiding plate  3  comprises a light-guiding substrate  32 , a first shielding layer  34 , a second shielding layer  36 , a background layer  38 , a transparent protecting layer  40  and an adhering layer  42 . The light-guiding substrate  32  has a first surface  322  and a second surface  324  opposite to the first surface  322 . The first shielding layer  34  is disposed on the first surface  322 , and the first shielding layer  34  comprises a first light-transmitting portion  342 . In the embodiment, the first shielding layer  34  can be, for example, a dark-color ink layer, which can be formed on the first surface  322  in a way of coating (e.g. printing). The first light-transmitting portion  342  of the first shielding layer  34  exposes a part of the light-guiding substrate  32 . 
         [0017]    The second shielding layer  36  is disposed on the second surface  324  by way of the adhering layer  42 . The second shielding layer  36  comprises a second light-transmitting portion  362 . The background layer  38  is disposed on the second shielding layer  36 . To be exactly in the embodiment, the background layer  38  is disposed on one surface of the second shielding layer  36  distanced from the light-guiding substrate  32 . The background layer  38  further comprises a third light-transmitting portion  382 . The transparent protecting layer  40  is disposed on the second shielding layer  36 . To be exactly in the embodiment, the transparent protecting layer  40  is disposed on one surface of the background layer  38  distanced from the light-guiding substrate  32 ; in other words, the background layer  38  is disposed between the transparent protecting layer  40  and the second shielding layer  36 . In the embodiment, the transparent protecting layer  40  is a transparent plastic sheet. The background layer  38  can be, for example, a light-color ink layer, which can be formed in a way of coating onto one surface of the transparent protecting layer  40  which the surface faces the light-guiding substrate  32 . On the other hand, the region without light-color ink is the third light-transmitting portion  382 . 
         [0018]    In said structure, the second shielding layer  36  can be a dark-color ink layer as well, which can be, for example, formed in a way of coating onto one surface of the background layer  38  which the surface faces the light-guiding substrate  32 . The second light-transmitting portion  362  is adjacent to the third light-transmitting portion  382 . A projection of the second light-transmitting portion  362  upon the second surface  324  is identical to a projection of the first light-transmitting portion  342  upon the second surface  324 . In the embodiment, the first light-transmitting portion  342  and the adjacent second light-transmitting portion  362  are disposed on one side of the light-guiding substrate  32 , while the third light-transmitting portion  382  is disposed on the other side of the light-guiding substrate  32 . The statement of “A projection of the second light-transmitting portion  362  upon the second surface  324  is identical to a projection of the first light-transmitting portion  342  upon the second surface  324 ” is provided as an example. In other embodiment, the projections of the second light-transmitting portion  362  and the first light-transmitting portion  342  are not limited to be identical or mutually covered. The second light-transmitting portion  362  needs only to correspond the first light-transmitting portion  342 , for allowing the light to pass through the first light-transmitting portion  342  and the light-guiding substrate  32 , and then to be emitted from the second light-transmitting portion  362 . 
         [0019]    When the light source  2  is disposed below the first light-transmitting portion  342 , the light (the pattern of the light is shown in an arrowed dash line) emitted by the light source  2  can pass through the first light-transmitting portion  342 , the light-guiding substrate  32 , the adhering layer  42 , the second light-transmitting portion  362 , the third light-transmitting portion  382  and the transparent protecting layer  40 . The thickness of the light-guiding substrate  32  in the embodiment is around 0.30 mm to 0.40 mm, so that the light may have a chance to scatter while going through the light-guiding substrate  32 . However, with the shielding of the second shielding layer  36 , the light may pass only through the second light-transmitting portion  362 , so that it alleviates the considerate light-halo phenomenon in prior art. In addition, the transparent protecting layer  40  in the embodiment may also induce the scattering effect, which the scattering effect is limited to a certain degree because the thickness of the transparent protecting layer  40  is around 0.125 mm only. 
         [0020]    Additionally, the transparent protecting layer  40 , mainly used for protecting the second shielding layer  36  and the background layer  38 , is not a must in the invention. The background layer  38 , mainly used for generating a background color on the light-guiding plate  3 , is not a must in the invention either. The adhering layer  42  is mainly used for adhering the second shielding layer  36 , isolated from another object (transparent protecting layer  40  in the embodiment), to the second surface  324  of the light-guiding substrate  32 . That is to say, the adhering layer  42  may be omitted when the second shielding layer  36  is directly formed on the second surface  324 . In summary, whether to implant the adhering layer  42  or not depends on the manufacturing procedures. On the other hand, whether to implant the transparent protecting layer  40  and the background layer  38  or not depends on the demanding of the design. 
         [0021]    Please refer to  FIG. 3 .  FIG. 3  is a flowchart of manufacturing the light-guiding plate  3  shown in  FIG. 2 . Firstly, step S 12   a  is executed to prepare the light-guiding substrate  32 . Afterward, step S 12   b  is executed to form the first shielding layer  34  on the first surface  322  of the light-guiding substrate  32 . The first shielding layer  34  can be, for example, a dark-color ink layer, which can be formed on the first surface  322  in a way of coating (e.g. printing). However, the first shielding layer  34  of the invention is not limited to the embodiment, but the first shielding layer  34  may have several alternative forms. For example, the first shielding layer  34  can be an opaque plate attached on the first surface  322 , which the opaque plate is punched to form a hole served as the first light-transmitting portion  342 . In other case, the first shielding layer  34  can be an object (e.g. plastic membrane), which is printed with dark-color ink and attached on the first surface  322 . 
         [0022]    Besides, step S 14   a  is executed to prepare the transparent plastic sheet (i.e. transparent protecting layer  40 ). Afterward, step S 14   b  is executed to form the background layer  38  on the transparent plastic sheet layer. Afterward, step S 14   c  is executed to form the second shielding layer  36  on the background layer  38 . The background layer  38  can be, for example, a light-color ink layer, which can be formed in a way of coating onto the transparent plastic sheet, and the second shielding layer  36  can be a dark-color ink layer which is further printed on the light-color ink layer (i.e. background layer  38 ). However, the second shielding layer  36  and the background layer  38  of the invention are not limited to the embodiment, but have several alternative forms. For example, the background layer  38  and the second shielding layer  36  may respectively be formed by attaching an opaque plate onto a transparent plastic sheet. In other case, the second shielding layer  36  can be an opaque plate, where the light-color ink treated as the background layer  38  is further printed. At last, the background layer  38  is attached to the transparent plastic sheet for forming said structure. In addition, when the light-color ink is printed, the third light-transmitting portion  382  is formed at the same time (the region without ink). When the dark-color ink is printed, the second light-transmitting portion  362  is formed at the same time (the region without ink). 
         [0023]    Afterward, step S 16  is executed to form the adhering layer  42  on the second shielding layer  36  or the second surface  324  of the light-guiding substrate  32 . The adhering layer  42  is a gum formed by spreading adhesive or a double-sided tape. In addition, even though the adhesive is pervious to light in some degree, it can still form a hollow region corresponding to the second light-transmitting portion  362  while forming the adhering layer  42 , for a better light transmittance. Finally, step S 18  is executed to utilize the adhering layer  42  to adhere the second shielding layer  36  onto the second surface  324  of the light-guiding substrate  32 . Accordingly, the light-guiding plate  3  in  FIG. 2  is completed. 
         [0024]    Please refer to  FIG. 4  and  FIG. 5 .  FIG. 4  is a flowchart of manufacturing a light-guiding plate according to another embodiment of the invention.  FIG. 5  is a schematic diagram illustrating the light-guiding plate  5  manufactured in  FIG. 4 . Firstly, step S 32  is executed to prepare a light-guiding substrate  32 . Afterward, step S 34  is executed to form a first shielding layer  34  on a first surface  322  of the light-guiding substrate  32 . Afterward, step S 36  is executed to form a second shielding layer  36  on a second surface  324  of the light-guiding substrate  32 . Afterward, step S 38  is executed to form a background layer  38  on the second shielding layer  36 . Finally, step S 40  is executed to form a transparent protecting layer  40 ′ on the background layer  38 . Accordingly, the light-guiding plate  5  in  FIG. 5  is completed. 
         [0025]    The difference between the light-guiding plate  5  in  FIG. 5  and the light-guiding plate  3  in  FIG. 2  is that the light-guiding plate  5  does not need the adhering layer  42  for adhering the second shielding layer  36  and the light-guiding substrate  32 . Besides, the transparent protecting layer  40 ′ of the light-guiding plate  5  can be formed on the second shielding layer  36  in a way of coating, not limited to a firm sheet (e.g. the transparent plastic sheet of the light-guiding plate  3 ). Said corresponding descriptions about the light-guiding substrate  32 , the first shielding layer  34 , the second shielding layer  36 , the background layer  38  and the transparent protecting layer  40  in the light-guiding plate  3  may be suitable in the light-guiding plate  5 , and are not mentioned repeatedly. 
         [0026]    In addition, the light-transmitting portions in said embodiments are not limited to be transparent, and not necessary to be entirely hollow. For example, the second shielding layer  36  can be produced in a way of coating the dark-color ink on a transparent thin sheet according to a pattern. At the same time, the second light-transmitting portion  362  is the region without coating the dark-color ink on the transparent thin sheet. Otherwise, the light-color ink layer (background layer  38 ) usually has a transmittance at certain degree. Therefore, the background layer  38  of the light-guiding plate  3  in  FIG. 3  may be coated onto the transparent protecting layer  40  entirely, and the region upon the background layer  38  corresponding to the second light-transmitting portion  362  of the second shielding layer  36  is defined as the third light-transmitting portion  382 . 
         [0027]    In summary, the light-guiding of the invention utilizes the first shielding layer and the second shielding layer to shield the light emitted by the light source layer by layer. It prevents the light-scattering effect caused by the light-guiding substrate, and further allows the light-transmitting portion being designed to have a more detailed pattern, so as to boost the instructing function. 
         [0028]    With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.