Abstract:
A mold which is made of a porous heat-resistant material comprises a first surface and a second surface opposite to the first surface. A plurality of light guide spots are formed on the first surface. The light guide spots are light guide spots. The first surface is a smooth polished surface, the mold enables direct manufacture of light guide plates for less heat expended.

Description:
FIELD 
       [0001]    The present disclosure relates to light guide plates, particularly to a mold, a method of manufacturing a glass light guide plate, and the light guide plate manufactured by the mold. 
       BACKGROUND 
       [0002]    Traditional light guide plate is made of polymethylmethacrylate (PMMA) and other materials. Yellowing and color bias will appear in the light absorption process of PMMA, which affects the energy-saving and durability of the light guide plate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    Implementations of the present technology will now be described, by way of example only, with reference to the attached figures, wherein: 
           [0004]      FIG. 1  is a schematic view of a substrate of a first embodiment of the present disclosure. 
           [0005]      FIG. 2  is a schematic view of a mold that is manufactured from the substrate of  FIG. 1 . 
           [0006]      FIG. 3  is a top plan view of a first surface of the mold of  FIG. 2 . 
           [0007]      FIG. 4  is a schematic view of a glass substrate placed on the mold in a method of manufacturing a glass light guide plate. 
           [0008]      FIG. 5  is a schematic view of a light guide plate using the manufacturing method of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure. 
         [0010]    One definition that applies throughout this disclosure will now be presented. 
         [0011]    The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like. 
         [0012]      FIG. 1  and  FIG. 2  illustrate a manufacturing method for a mold for manufacturing a light guide plate. 
         [0013]      FIG. 1  illustrates a substrate  10 . In the illustrated embodiment, the substrate  10  is a cubic. The substrate  10  includes a first surface  12  and a second surface  14 . In other embodiments, the substrate  10  can be any other shape, provided that the substrate  10  has two parallel and opposite smooth surfaces. 
         [0014]    The substrate  10  is made of porous heat-resistant material. The porous heat-resistant material is selected from one or several combinations of Hexagonal Boron Nitride (HBN), silica (SiO2) and alumina (Al2O3), and hexagonal carbon (C). The porous heat-resistant material should have high mechanical strength. The density (D) of the porous heat-resistant material range is from about 2.4 grams per cubic centimeter (g/cm3) to about 6.4 grams per cubic centimeter (g/cm3). The porous heat-resistant material should withstand temperatures of between about 500° C. and about 1500° C. The porous heat-resistant material should maintain its shape at these temperatures for a long time. Holes  16  are formed in the porous heat-resistant material, the holes  16  are distributed evenly and are interconnected. The size of aperture (d) of the holes  16  is from about 0.1 nanometers (nm) to about 2.1 microns (μm). Thus, the whole substrate  10  is permeable to air. 
         [0015]      FIG. 2  illustrates a mold  20 . The mold  20  is manufactured using the substrate  10 . 
         [0016]    In detail, the substrate  10  is processed. Light guide spots  22  are formed in the first surface  12 .  FIG. 3  illustrates that the light guide spots  22  are distributed on the first surface  12 . A surface processing method can be any of mechanical drilling, laser drilling, chemical etching, physical vapor deposition (PVD), and chemical vapor deposition (CVD). 
         [0017]    Each light guide spot  22  has a same shape and size. In the illustrated embodiment, the plurality of light guide spots  22  is spread on the first surface  12  according to the desired optical design. The light guide spots  22  are substantially hemispherical recesses. Each of the plurality of light guide spots  22  have a diameter ranging from 30 microns to 400 microns in a direction parallel to first surface  12 . The plurality of light guide spots  22  have a depth ranging from 30 microns to 400 microns in a direction perpendicular to the first surface  12 . 
         [0018]    Due to a roughness requirement of the light guide plate surface, the mold  20  is polished to obtain a smooth first surface  12  (molding surface) after the formation of light guide spots  22 . 
         [0019]      FIG. 4  illustrates the mold  20  and a glass substrate  30 . The glass substrate  30  is cubic. The shape and size of glass substrate  30  are substantially equal to those of the mold  20 . However, the glass substrate  30  can have any thickness. In the illustrated embodiment, the thickness of the glass substrate  30  is far smaller than the thickness of the mold  20 . The glass substrate  30  includes an upper surface  32  and a lower surface  34 . The upper surface of  32  and the lower surface  34  are on opposite sides of the glass substrate  30 . 
         [0020]    The glass substrate  30  is manufactured into a light guide plate  100  by the following steps. The mold  20  is heated to the glass transition temperature Tg of the glass substrate  30  (temperature of transforming polymer from high elastic state into glass state). The glass transition temperature Tg of the glass substrate  30  is less than about 1500° C. The mold  20  is kept at this temperature, and the lower surface  34  of the glass substrate  30  is placed on the first surface  12 . During the molding operation, air is exhausted from the mold  20  to generate suction (negative pressure) and the glass substrate  30  is absorbed onto the first surface  12 . The glass substrate  30  is softened by heat conduction, the softened glass filling the plurality of light guide spots  22  on the first surface  12 . Heating is removed from the mold  20 , the temperature of the mold  20  is reduced below the glass transition temperature Tg and gradually cooled to room temperature. The mold  20  is removed, and the glass light guide plate  100  is thereby obtained. 
         [0021]      FIG. 5  illustrates the glass light guide plate  100 . The glass light guide plate  100  includes an upper surface  32  and a lower surface  34 . The upper surface  32  and the lower surface  34  are located at the opposite sides of the glass light guide plate  100 . A plurality of protrusions  340  are formed on the lower surface  34 . The plurality of protrusions  340  are spread on the lower surface according to the desired optical design. The number and positions of the plurality of protrusions  340  correspond to the number and positions of the light guide spots  22 . Each of the plurality of protrusions  340  is substantially the same size and shape. The protrusions  340  are arc-shaped protrusions. The plurality of protrusions  340  have a diameter range from 30 microns to 400 microns in a direction parallel to the lower surface  34 . The depth of the protrusions  340  ranges from 30 microns to 400 microns in a direction perpendicular to the lower surface  34 . 
         [0022]    The mold  20  is made of a porous heat-resistant material, the porosity contributing to the generation of suction during molding of the plate  100  (air is removed through the pores), thereby the softened glass material molding is absorbed on the forming surface after heating to the glass transition temperature. 
         [0023]    The glass light guide plate  100  can be polished to form a smooth surface depending on the circumstances after molding. 
         [0024]    The plurality of light guides  22  can be selected from different desired optical designs based on different refractive indexes of the glass substrate  30 . 
         [0025]    The glass substrate  30  can be post-processed by physical vapor deposition for example, or chemical vapor deposition, or surface treatment. 
         [0026]    The manufacturing method of the glass light guide plate of the present disclosure provides a glass molding technology, microstructures of light guide plate being directly formed on the glass surface. The glass light guide plate  100  has a better light guide plate penetration than traditional PMMA, and is more durable and energy-efficient. Yellowing and color biasing in the glass production process of the light guide plate are much reduced. 
         [0027]    The embodiments shown and described above are only examples. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, including in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims.