Abstract:
The present invention relates to an apparatus for molding a glass substrate, and more specifically, to an apparatus for molding a glass substrate capable of forming a glass substrate in a 3D shape and preventing the shape of a vacuum hole from transferring onto the surface of the substrate. To this end, the present invention provides the apparatus for molding a glass substrate comprising: a molding frame; a molding groove formed on one surface of the molding frame; at least one vacuum hole formed on the molding frame at the lower portion of the molding groove and is connected to an external vacuum device; and a pressure-reducing groove, which is formed between the molding groove and the vacuum hole and allows communication between the molding groove and the vacuum hole, for reducing vacuum pressure applied to the glass substrate positioned on the molding groove through the vacuum hole.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an apparatus for shaping a glass substrate, and more particularly, to an apparatus for shaping a glass substrate able to shape a glass substrate to have a three-dimensional (3D) shape while preventing the shape of a vacuum hole from being transferred to the surface of the glass substrate during vacuum shaping. 
         [0003]    2. Description of Related Art 
         [0004]    Glass products are used in a variety of fields. For example, mobile phones use a cover glass to protect a touchscreen glass. Recently, products, the design of which can be varied using cover glasses having unique shapes according to final makers, are gaining increasing interest. 
         [0005]    Cover glasses that have been used for mobile phones of the related art have a flat shape or curved corners. However, in response to the various functions and designs of mobile phones, curved glasses in which a pair of opposing edges from among the four edges is curved are currently being used for mobile phones. 
         [0006]    A method of fabricating such a cover glass includes: preparing a mold having a shaping recess with a plurality of shaping holes formed on the bottom of the shaping recess; disposing the mold on a heated glass substrate; and applying vacuum, i.e. a force of drawing the glass substrate to the plurality of shaping holes, to the glass substrate through the plurality of shaping holes, thereby shaping the glass substrate to have the shape of the shaping recess. However, in this case, a high-pressure vacuum causes the shape of the vacuum holes to be transferred onto the surface of the shaped glass substrate, thereby leaving marks thereon. 
       RELATED ART DOCUMENT 
       [0007]    Patent Document 1: Korean Patent No. 10-0701653 (Mar. 23, 2007) 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    Various aspects of the present invention provide an apparatus for shaping a glass substrate able to shape at least one edge portion of the four edges of a glass substrate to have a curved surface while preventing the shape of a vacuum hole from being transferred to the surface of the glass substrate during vacuum shaping. 
         [0009]    In an aspect of the present invention, provided is an apparatus for shaping a glass substrate that includes: a molding frame; a shaping recess disposed on one surface of the molding frame; at least one vacuum hole formed in the molding frame below the shaping recess, the at least one vacuum hole being connected to an external vacuum device; and at least one decompression recess defined between the shaping recess and the at least one vacuum hole such that the shaping recess communicates with the at least one vacuum hole. The decompression recess lessens vacuum pressure applied to the glass substrate disposed on the shaping recess through the at least one vacuum hole. 
         [0010]    According to an embodiment of the present invention, the width of the decompression recess may be greater than the width of the at least one vacuum hole. 
         [0011]    The apparatus may include a plurality of the vacuum holes and a plurality of the decompression recesses. Each decompression recess may correspond to each of the plurality of the vacuum holes. 
         [0012]    The apparatus may include a plurality of the vacuum holes. At least two vacuum holes of the plurality of the vacuum holes may be connected to one decompression recess of the at least decompression recess. 
         [0013]    Here, the at least two vacuum holes may be arranged in a row or column, and the apparatus may include a plurality of the decompression recesses, each of which extends along and is connected to the at least two vacuum holes in the row or column. 
         [0014]    In addition, each of the plurality of the decompression recesses may have a trench structure in which the at least two vacuum holes arranged in a row or column is exposed. 
         [0015]    At least one wall surface of the shaping recess may be a curved surface such that at least one edge portion of four edges of the glass substrate is shaped to have a curved surface. 
         [0016]    The vacuum hole may have a first path having one end adjoining to the decompression recess and a second path connected to the other end of the first path. The inner diameter of the second path may be greater than the inner diameter of the first path. 
         [0017]    According to the present invention as set forth above, the decompression hole for reducing a vacuum pressure applied to a glass substrate through the vacuum holes is formed at one side of the vacuum holes that face the glass substrate. With this configuration, a uniform pressure can be applied to one area of the glass substrate that faces the vacuum holes and the other area of the glass substrate, thereby preventing the shape of the vacuum holes from being transferred to the surface of the glass substrate that would otherwise leave marks on the surface of the glass substrate. 
         [0018]    In addition, at least one wall surface of the shaping recess is formed as a curved surface, with which at least one edge portion of the four edges of the glass substrate can be shaped to have a curved surface, i.e. the glass substrate can be shaped to have a three-dimensional (3D) shape. 
         [0019]    Furthermore, the diameter of one portion of each vacuum hole connected to the vacuum device is formed greater than the diameter of the opposite portion of each vacuum hole. This can consequently maximize the vacuum pressure applied to the glass substrate and ensure reproducibility in the shaping of the glass substrate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a partial perspective view illustrating an apparatus for shaping a glass substrate according to a first exemplary embodiment of the present invention; 
           [0021]      FIG. 2  is a cross-sectional view taken along line A-A in  FIG. 1 ; 
           [0022]      FIG. 3  is a partial perspective view illustrating an apparatus for shaping a glass substrate according to a second exemplary embodiment of the present invention; 
           [0023]      FIG. 4  is a cross-sectional view taken along line B-B in  FIG. 3 ; 
           [0024]      FIG. 5  is a cross-sectional view taken along line C-C in FIG.  3 ; 
           [0025]      FIG. 6  is a partial perspective view illustrating an apparatus for shaping a glass substrate according to a third exemplary embodiment of the present invention; and 
           [0026]      FIG. 7  is an enlarged cross-sectional view of an area “D” in  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Reference will now be made in detail to an apparatus for shaping a glass substrate according to the present invention, embodiments of which are illustrated in the accompanying drawings and described below, so that a person skilled in the art to which the present invention relates could easily put the present invention into practice. 
         [0028]    Throughout this document, reference should be made to the drawings, in which the same reference numerals and signs are used throughout the different drawings to designate the same or similar components. In the following description of the present invention, detailed descriptions of known functions and components incorporated herein will be omitted in the case that the subject matter of the present invention is rendered unclear. 
         [0029]    Reference will now be made to an apparatus for shaping a glass substrate according to a first exemplary embodiment of the present invention in conjunction with  FIG. 1  and  FIG. 2 . 
         [0030]      FIG. 1  is a partial perspective view illustrating the apparatus for shaping a glass substrate  100  according to the first embodiment, and  FIG. 2  is a cross-sectional view taken along line A-A in  FIG. 1 . 
         [0031]    As illustrated in  FIG. 1  and  FIG. 2 , the apparatus for shaping a glass substrate  100  according the first embodiment is a shaping mold that can shape a glass substrate to have a three-dimensional (3D) shape, i.e. shape at least one edge portion of the four edges of the glass substrate to have a curved surface, using a vacuum. Herein, the shaping process using vacuum, i.e. the vacuum shaping, is a method of shaping a glass substrate (not shown) by heating the glass substrate (not shown) to a preset temperature, bringing the heated glass substrate (not shown) into contact with the shaping mold, and pressing the glass substrate (not shown) against the shaping mold using vacuum pressure. That is, the apparatus for shaping a glass substrate  100  according this embodiment is a shaping mold that shapes the glass substrate (not shown) having the shape of a two-dimensional (2D) flat glass to a 3D curved glass by vacuum shaping. 
         [0032]    For this, the apparatus for shaping a glass substrate  100  according this embodiment includes a molding frame  110 , a shaping recess  120 , vacuum holes  130  and decompression recesses  140 . 
         [0033]    The molding frame  110  forms the outer shape of the apparatus for shaping a glass substrate  100 . For example, the molding frame  110  may have an overall box-shaped structure. The molding frame  110  may be made of a material having superior resistance to abrasion, impacts and heat, such as carbon steel, alloy steel or stainless steel. 
         [0034]    The molding recess  120  is formed inward from one surface of the molding frame  110 , more particularly, one surface of the molding frame  110  that is to face the glass substrate (not shown). Here, since the apparatus for shaping a glass substrate  100  according this embodiment is an apparatus that shapes the glass substrate (not shown) such that the glass substrate (not shown) has a 3D shape, i.e. at least one edge portion of the four edges of the glass substrate (not shown) has a curved surface, at least one wall surface of the shaping recess  120  that determines the shape of the glass substrate (not shown) is formed as a curved surface. In addition, the width of the shaping recess  120  is smaller than that of the glass substrate (not shown) in order to impart the curved surface to the glass substrate (not shown). 
         [0035]    The vacuum holes  130  provide paths through which vacuum pressure generated from an external vacuum device (not shown) is transferred to the glass substrate (not shown) aligned on the shaping recess  120 . When the glass substrate (not shown) is being shaped, vacuum, i.e. a force of drawing the glass substrate (not shown) toward the shaping recess  120 , is applied to the glass substrate (not shown) through the vacuum holes  130 , thereby shaping the glass substrate (not shown) to have the shape of the shaping recess  120 . The vacuum holes  130  are formed in the molding frame  110  below the shaping recess  120 . The vacuum holes  130  may be in the shape of cylinders. In addition, as illustrated in  FIG. 1  and  FIG. 2 , a plurality of vacuum holes  130  may be provided. The plurality of vacuum holes  130  may be arranged as being aligned in columns and rows in order to cause vacuum pressure to be uniformly applied over the entire surface of the glass substrate (not shown). The plurality of vacuum holes  130  is connected to a vacuum device (not shown) such as a vacuum pump that is disposed outside. For the sake of efficiency, the plurality of vacuum holes  130  may be connected, at one end thereof, to a common path (not shown) through which the plurality of vacuum holes  130  communicates with each other, and the vacuum device (not shown) may be connected to the common path (not shown) in a one-to-one relationship. That is, the plurality of vacuum holes  130  may be connected to the vacuum device (not shown) via the common path (not shown), and vacuum pressure applied from the vacuum device (not shown) may be connected uniformly distributed before being applied to the glass substrate (not shown) via each of the plurality of vacuum holes  130 . 
         [0036]    The decompression recesses  140  are defined between the shaping recess  120  and the vacuum holes  130  such that the vacuum holes  130  communicate with the shaping recess  120 , thereby allowing vacuum pressure applied through the vacuum holes  130  to be transferred to the shaping recess  120 . The decompression recesses  140  are configured to lessen vacuum pressure applied to the glass substrate (not shown) disposed or aligned on the vacuum recess  120  through the vacuum holes  130 . For this, the width of each of the decompression recesses  140  may be greater than the width of each of the vacuum holes  130 . As illustrated in  FIG. 1  and  FIG. 2 , the decompression recesses  140  may be in the shape of cylinders like the vacuum holes  130 . In addition, the decompression recesses  140  may correspond to the vacuum holes  130  in a one-to-one relationship. When viewed on a plane, one vacuum hole  130  defining a circle is located inside a greater circle defined by one decompression recess  140 . Accordingly, when vacuum pressure is transferred to the glass substrate (not shown) through the narrow vacuum holes  130 , it is lowered through the wider decompression holes  140  before being applied to the glass substrate (not shown). 
         [0037]    As in the related art, when the vacuum holes are in direct contact with the glass substrate (not shown), the shape of the vacuum holes may be transferred to the surface of the glass substrate (not shown) due to high pressure, thereby leaving marks on the surface of the glass substrate (not shown). However, as described above, when the vacuum pressure applied to the glass substrate (not shown) through the vacuum holes  130  is lessened by the decompression recesses  140 , it is possible to reduce the difference between the pressure applied to one area of the glass substrate (not shown) that faces the vacuum holes  130  and the pressure applied to the other area of the glass substrate (not shown) or make uniform pressure be applied to both areas of the glass substrate, thereby preventing the shape of the vacuum holes  130  from being transferred to the surface of the glass substrate (not shown) that would otherwise leave marks on the surface of the glass substrate (not shown). 
         [0038]    Reference will now be made to an apparatus for shaping a glass substrate according to a second exemplary embodiment of the present invention in conjunction with  FIG. 3  to  FIG. 5 . 
         [0039]      FIG. 3  is a partial perspective view illustrating the apparatus for shaping a glass substrate  200  according to the second embodiment,  FIG. 4  is a cross-sectional view taken along line B-B in  FIG. 3 , and  FIG. 5  is a cross-sectional view taken along line C-C in  FIG. 3 . 
         [0040]    As illustrated in  FIG. 3  to  FIG. 5 , the apparatus for shaping a glass substrate  200  according to the second embodiment includes a molding frame  110 , a shaping recess  120 , vacuum holes  130  and decompression recesses  240 . 
         [0041]    Since the second embodiment is substantially identical to the first embodiment except for the structure of the decompression recesses, like reference numerals will be used to designate the same or like elements, descriptions of which are omitted. 
         [0042]    As illustrated in  FIG. 3  to  FIG. 5 , according to the second embodiment, a plurality of vacuum holes  130  and a plurality of decompression recesses  240  are provided. Here, at least two vacuum holes  130  are connected to each decompression recess  240 . Specifically, according to this embodiment, each decompression recess  240  extends along a row or column of the plurality of vacuum holes  130 , and a group of vacuum holes  130  of the plurality of vacuum holes  130  arranged in a row or column is connected to each decompression recess  240  and is exposed toward the shaping recess  120 . For example, each decompression recess  240  has a trench structure, with which the corresponding group of vacuum holes  130  is exposed toward the shaping recess  120 . In this case, like the decompression recesses ( 140  in  FIG. 2 ) according to the first embodiment of the present invention, the width of each decompression recess  240  is greater than the width of each vacuum hole  130 . Since this structure expands the space, a high-vacuum pressure passing through the plurality of vacuum holes  130  can be lessened, thereby preventing the shape of the vacuum holes  130  from being transferred to the surface of the glass substrate (not shown) that would otherwise leave marks the glass surface. 
         [0043]    Reference will now be made to an apparatus for shaping a glass substrate according to a third exemplary embodiment of the present invention in conjunction with  FIG. 6  and  FIG. 7 . 
         [0044]      FIG. 6  is a partial perspective view illustrating the apparatus for shaping a glass substrate  300  according to the third embodiment, and  FIG. 7  is an enlarged cross-sectional view of an area “D” in  FIG. 7 . 
         [0045]    As illustrated in  FIG. 6  and  FIG. 7 , the apparatus for shaping a glass substrate  300  according to the third embodiment includes a molding frame  110 , a shaping recess  120 , vacuum holes  330  and decompression recesses  140 . 
         [0046]    Since this embodiment is substantially identical to the first embodiment except for the structure of the vacuum holes, like reference numerals will be used to designate the same or like elements, descriptions of which are omitted. 
         [0047]    Each of the vacuum holes  330  according to this embodiment has a two-section structure that includes two sections having different diameters. As illustrated in  FIG. 6  and  FIG. 7 , each vacuum hole  330  includes a first path  331  having one end adjoining to a corresponding decompression recess  140  and a second path  332  connected to the other end of the first path  331 . The inner diameter of the second path  332  may be greater than the inner diameter of the first path  331 . With this configuration, a vacuum pressure, i.e. a drawing force, applied from a vacuum device (not shown) can be enhanced when it is transferred from the greater space of the second path  332  to the smaller space of the first path  331 , thereby maximizing the vacuum pressure applied to a glass substrate (not shown). This can consequently ensure reproducibility in the shaping of the glass substrate (not shown). 
         [0048]    The foregoing descriptions of specific exemplary embodiments of the present invention have been presented with respect to the drawings. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible for a person having ordinary skill in the art in light of the above teachings. 
         [0049]    It is intended therefore that the scope of the present invention not be limited to the foregoing embodiments, but be defined by the Claims appended hereto and their equivalents.