Abstract:
A touchscreen display device includes a display module and an electrically conductive and light transmissive layer provided over the display module to allow detection of touch input. The electrically conductive and light transmissive layer includes a transparent substrate and a transparent layer provided over the transparent substrate. The transparent layer has first and second surfaces, which are opposing surfaces, and the first surface faces the transparent substrate. The second surface includes a plurality of protrusions extending in different directions such that the plurality of first protrusions intersect to form recess regions on the second surface. The recess regions include a plurality of second protrusions, and the second protrusions have a height and a width less than the first protrusions. At least one metallic wiring layer is formed on the plurality of first protrusions including at locations where the first protrusions intersect.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a Continuation-In-Part application of U.S. application Ser. No. 14/358,701 having a 371(c) filing date of May 15, 2014, which is a U.S. National Stage application of International Application No. PCT/KR2012/010739 filed Dec. 11, 2012, claiming priority to Korean Application No. 10-2011-0137217 filed on Dec. 19, 2011, whose entire disclosures are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    The present disclosure relates to a transparent substrate having a nano pattern for use to a touchscreen of a display module. 
         [0004]    2. Related Art 
         [0005]    When manufacturing a semiconductor device, a word line, it is necessarily required to implement various fine patterns such as a digit line, a contact and the like. A lithograph technology has been generally applied to form these fine patterns. 
         [0006]    A contact lithograph method which has been traditionally and widely used enables the pattern to be formed throughout a wide area. However, due to a limit of the diffraction of light, it was problematic that a pitch of the fine pattern which can be formed is limited (1˜2 μm). 
         [0007]    Accordingly, to solve this problem, a stepper method, a scanner method, a holographic lithography method and the like were developed. However, these methods need complicated and sophisticated equipment and incur high expenses. Further, the methods have a limit in view of the fact that an area which can form a pattern is limited. That is, the conventional lithograph method is basically limited to implement nonoscale fine patterns due to the problems such as a limitation of equipment or a process property. More specifically, upon the use of the conventional lithography technology, it would be difficult to implement nanoscale patterns which are uniformly formed throughout a large area of more than 8 inch. 
         [0008]    According to the aforesaid problems, a method of forming a porous metal thin film using a porous template made of a metal material as disclosed in Korean Laid-Open Patent Publication No. 2011-0024892, and forming nano patterns using the porous metal thin film as a catalyst was suggested. The method was problematic in that because the porous template should be prepared in advance, it is inconvenient to use the method, and because a catalyst growth method is used, nano patterns can be formed at only desired regions. Moreover, it was problematic that the nano patterns cannot be formed on a transparent substrate. 
         [0009]    The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, wherein: 
           [0011]      FIG. 1  and  FIG. 2  are flow charts showing the order of a method of manufacturing a transparent substrate having a nano pattern according to the present disclosure. 
           [0012]      FIG. 3  through  FIG. 9  are the exemplary views of processes illustrating roughly the manufacturing processes of a transparent substrate having a nano pattern according to the present disclosure. 
           [0013]      FIG. 10  illustrates a touchscreen comprising the transparent substrate having a nano pattern of the present disclosure. 
           [0014]      FIGS. 11A-11C  illustrate the arrangement of the transparent substrate as a touch screen in various display module configurations. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]      FIG. 1  and  FIG. 2  are flow charts showing the order of a method of manufacturing a transparent substrate having a nano pattern according to the present disclosure. A method of manufacturing a transparent substrate having a nano pattern according to the present disclosure may include: forming a resin layer made of a transparent material on a transparent substrate (S 1 ); forming at least one or more unit pattern parts, which are composed of a first and a second pattern areas in which a plurality of grid patterns are formed, and a protrusion pattern formed between the first pattern area and the second pattern area, on the resin layer (S 3 ); and forming a nanoscale metal layer on the protrusion pattern (S 5 ). 
         [0016]    A material of the transparent substrate in used in step S 1  may be glass, quartz, a polymer made of a transparent material, for example, publicly known polymer materials such as PET (polyethylene terephthalate), PC (polycarbonate), PI (polyimide). In addition to this, various flexible substrates may be used. The material is not limited. 
         [0017]    After the transparent substrate is prepared, a resin layer is formed by applying a resin made of a transparent material to the transparent substrate. At this time, the resin may use a thermosetting polymer or a photo curable polymer. Meanwhile, to improve a bonding ability between the resin layer and the transparent substrate, the resin layer may be also formed by coating the transparent substrate with an adhesive before applying the resin, and thereafter applying the resin to the transparent substrate. 
         [0018]    After step S 1 , at least one or more unit pattern parts, which are composed of a first pattern area and a second pattern area in which a plurality of grid patterns are formed, respectively, and a protrusion pattern formed between the first pattern area and the second pattern area, is formed on the resin layer (S 3 ). Specially, step S 3  may be performed as described below. 
         [0019]    First, a master mold is produced (S 31 ), the master mold having at least one or more unit mold pattern parts, which are composed of the first mold pattern area and the second mold pattern area in which a plurality of grid mold patterns are formed respectively, between the plurality of grid mold patterns there are formed with recesses, and a concave mold pattern formed between the first mold pattern area and the second mold pattern area. 
         [0020]    The plurality of nanoscale grid mold patterns are first formed on an original material of the master mold using a space lithography process, for example, “a method of manufacturing a nanoscale pattern having a large area” as described in Korean patent application No. 10-2010-0129255. The master mold of the present disclosure may be produced by forming a concave mold pattern to divide a first mold pattern area and a second mold pattern area and forming one or more unit mold pattern parts. At this time, specifically, the formation method of the concave mold pattern may be performed by an electron-beam lithography process. However, the present disclosure is not limited to this. 
         [0021]    Meanwhile, a width (A) of a recess between the gird mold patterns of the first mold pattern area or the second mold pattern area may be formed in a range of 50 to 100 nm. A width (B) of concave or squared recess mold pattern may be formed in a range of 200 to 1000 nm. The width (C) of the protrusions in the first mold pattern area or the second mold pattern area may be in a range of 50 to 100 nm. The master mold produced by this method is reusable until it is damaged. Furthermore, the master mold can continue to use at an imprinting process, causing economical advantages such as the reduction of a raw material charge and a production cost. 
         [0022]    Then, the master mold produced in step S 31  is arranged in an upper part of the resin layer, and one or more unit pattern parts corresponding to one or more unit mold pattern parts are formed on the resin layer through an imprinting process for pressurizing the resin layer (S 33 ). Here, the unit pattern parts mean a structure including the first pattern area corresponding to the first mold pattern area, the second pattern area corresponding to the second mold pattern area, and the protrusion pattern unit corresponding to the concave mold pattern. The plurality of grid patterns corresponding to recesses between the plurality of grid mold patterns are provided in the first pattern area and the second pattern. 
         [0023]    A process of hardening the resin layer is performed (S 35 ). At this time, in a case where the resin layer is made of a thermosetting polymer, the resin layer is hardened by applying heat thereto. In a case where the resin layer is a photo curable polymer, the resin layer is hardened by irradiating ultraviolet rays thereto. Thereafter, step S 3  of the present disclosure may be conducted by releasing the master mold from the resin layer (S 37 ). 
         [0024]    Then, in step S 5 , the nanoscale metal layer is formed on the protrusion pattern of the resin layer. A metallic layer is first deposited on the grid patterns and the protrusion pattern. At this time, the deposited metal may use any one of Al, Cr, Ag, Cu, Ni, Co and Mo or an alloy thereof. However, the present disclosure should not be limited to this, and other metals may be appropriately used as need. The deposition method of the metal may be at least one method of a sputtering method, a chemical vapor deposition method, and an evaporation method. However, this is only one example. In addition to the methods, all deposition methods, which have been developed and commercialized or can be embodied according to future technical development, may be used. 
         [0025]    Meanwhile, a height of depositing the metal may be formed to be more than a pitch value (See “P” of  FIG. 7 ) of the grid patterns, and the metal may be uniformly deposited on each grid pattern and the protrusion pattern. The pitch value being a distance between a center of a protrusion to a center of an adjacent protrusion. This pitch value may be in a range of 100 to 200 nm. This is intended to easily remove the metal formed on the grid patterns at an etching process later. 
         [0026]    After the metal is deposited, a wet etching process is performed thereon, so isotropic etching is performed at exposed three sides of the metal. Thus, the metal deposited on the grid patterns is etched, or a part bonded to the grid patterns is peeled off. Consequently, the metal deposited on the grid patterns is removed, and the metal on the protrusion pattern remain so as to form the metal layer. The reason why the metal deposited on the grid patterns is removed and the metal on the protrusion pattern remains so as to form the metal layer is because a contact area between the metal deposited on the grid patterns and an etching solution used during the wet etching process is more than the metal deposited on the protrusion pattern. Thus, the transparent substrate having the nano pattern of the present disclosure, including the nano pattern and nanoscale metal layer may be produced. 
         [0027]    As the wet etching process is used, the process can be performed even at room temperature, and as the manufacturing process of the master mold can be performed separately, flexible processes can be secured. Furthermore, the master mold is available until it is damaged, causing the reduction of a raw material charge and a production cost. 
         [0028]    The nano patterns may be uniformly implemented throughout the wide area of the transparent substrate, and the nanoscale metal layer may be also uniformly formed on the transparent substrate. Thus, it is advantageous that the transparent substrate having electrical conductivity equal to ITO can be provided at a low cost, and an Ag mesh which is emerging as a substitute for the ITO can be produced as a nanoscale pattern. Accordingly, the transparent substrate with nano patterns can be utilized in various fields such as a touch panel, a liquid crystal device, a solar cell and the like. 
         [0029]      FIG. 3  through  FIG. 9  are the exemplary views of processes illustrating roughly the manufacturing processes of a transparent substrate having a nano pattern according to the present disclosure. As illustrated in  FIG. 3 , a structure  10   a  in which the plurality of nanoscale grid mold patterns  11  on an upper surface thereof are formed is produced. At this time, the space lithograph process may be used as a method of forming the grid mold pattern  11 . This is the same as described in the explanation of  FIG. 2 . 
         [0030]    Thereafter, as illustrated in  FIG. 4  and  FIG. 5 , a master mold  10  having at least one or more unit mold pattern parts  10   b  are produced by patterning the structure  10   a  as illustrated in  FIG. 3  through an electron-beam lithography process. At this time, the unit mold pattern parts  10   b  are composed of a first mold pattern area  13 , a second mold pattern area  17 , and a concave or squared recessed mold pattern  15  formed between the first mold pattern area  13  and the second mold pattern area  17 . The mold pattern area  13  and the second mold pattern area  17  have a plurality of grid mold patterns  11  with recesses between them. The grid mold pattern  11  is shown as a series of protrusions, e.g., squared protrusions, but other shaped protrusion patterns are possible. 
         [0031]    Here, a width (B) of the concave mold pattern  15  is formed to be wider than a width (A) of the recess between the patterns of the first mold pattern area  13  or a width of the recess between the patterns of the second mold pattern area  17 . More specifically, the width (B) of the concave mold pattern  15  may be formed in the range of 200 to 1000 nm. The width (A) of the recess between the patterns of the first mold pattern area  13  or the width (A) of the recess between the patterns of the second mold pattern area  17  may be formed in the range of 50 to 100 nm. The width (C) of the protrusions may be in the range of 50 to 100 nm. However, the present disclosure is not limited to this. Also, a depressed depth of the concave mold pattern  15  may be formed to be deeper than a height of the grid mold pattern  11 . In an embodiment, the height of the pattern  15  is greater than the height of the pattern  11  and the height of the pattern  11  is less than the height of the pattern  15 . 
         [0032]    Then, as illustrated in  FIG. 6 , the imprinting process for pressurizing the resin layer  30  formed on the transparent substrate  20  using the master mold ( 10  of  FIG. 5 ), in which one or more unit mold pattern parts  10   b  are formed, is conducted. The detailed explanation on the transparent substrate  20  and the resin layer  30  is the same as described in the explanation of  FIG. 1  and  FIG. 2 , and thus is omitted. The master mold ( 10  of  FIG. 5 ) is released from the resin layer  30  after applying a photo curing process or a heat curing process, as illustrated in  FIG. 7 , so that one or more unit pattern parts  30   b  corresponding to the unit mold pattern parts ( 10   b  of  FIG. 5  and  FIG. 6 ) may be formed on the resin layer  30 . Here, the unit pattern parts  30   b  are composed of the first pattern area  33 , the second pattern area  37 , and the protrusion pattern  35  formed between the first pattern area  33  and the second pattern area  37 . The first pattern area  33 , and the second pattern area  37  have the plurality of grid patterns  31 , and the protrusion  35  have shapes and patterns that complements the shapes and patterns recesses of the first mold pattern area  13 , of the second mold pattern area  17 , and the recess  15 . 
         [0033]    Due to the imprint of the master mold on the resin layer  30 , the dimensions are substantially the same in a complementary manner. A width (E) of the protrusion pattern  35  may be formed to be wider than a width of the grid pattern of the first pattern area  33  or a width of the grid pattern of the second pattern area  37 . More specifically, the width (E) of the protrusion pattern  35  may be formed in a range of 200 to 1000 nm, i.e., width (E) equals width (B). The width (D) of the grid pattern  31  of the first pattern area  33  or the width of the grid pattern of the second pattern area  37  may be formed in a range of 50 to 100 nm, i.e., width (D) equals width (A). The width (F) of the recesses of the first pattern area  33  or the second grid pattern area  37  may be formed in a range of 50 to 100 nm, i.e, width (F) equals width (C). However, the present disclosure is not limited to this. Also, a height of the protrusion pattern  35  is formed to be higher than a height of the grid patterns  31 . 
         [0034]    Then, the metal is deposited on the grid patterns  31  and the protrusion pattern  35 , and the metal deposited on the grid patterns  31  is removed through the wet etching process, so that the nanoscale metal layer  40  may be formed on the protrusion pattern  35 , as illustrated in  FIG. 8 . The width of the metal may be the same or smaller than the width (E), and the height of the metal layer  40  may be greater than or equal to 100 nm. In the above disclosed embodiments, although the protrusion pattern  35  is illustrated as higher than grid patterns  31  formed in the first pattern area and the second pattern area, the present disclosure is not limited thereto. The protrusion pattern  35  may also be substituted with a wide pattern  35  that is equal in height to the grid patterns  31  (i.e., narrow patterns  31 ), but is wider than individual narrow patterns  31 . 
         [0035]    Thus, the transparent substrate having the nano pattern with a large area as illustrated in  FIG. 9  can be obtained, which illustrates a top view of transparent substrate, where  FIG. 8  is a section view of the area shown in dotted lines. As shown, the metal layer  40  are formed in X and Y directions on top of the protrusion pattern  35  to form a mesh of x and y signal lines x1-x4 and y1-y4 with a plurality of first and second pattern areas  33  and  37 . 
         [0036]      FIG. 10  illustrates a touchscreen  50  incorporating the transparent substrate having nano pattern, which is provided in area A. A black mask  51  is provided at the periphery of The touchscreen display device  50  to hide any circuitry or visible signal lines, e.g., x and y signal lines of the transparent substrate, which are connected to input and/or output lines  52 . 
         [0037]      FIG. 11A  illustrates a first implementation of the touchscreen  50  in a display device  60 . In this embodiment, the touchscreen  50  using a transparent film  32  with signal lines, e.g., x or y signal lines, is adhered using an adhesive  62  between an LCD module  64  and a window  66 . 
         [0038]      FIG. 11B  illustrates a second implementation of the touchscreen  50  in a display device  60 . In this embodiment, the touchscreen  50  using glass  34  as the transparent substrate with signal lines, e.g., x or y signal lines, is adhered using an adhesive  62  between an LCD module  64  and a window  66 . 
         [0039]      FIG. 11C  illustrates a third implementation of the touchscreen  50  in a display device  60 . In this embodiment, a window  66  having either a film or glass as a substrate with x or y signal lines serve as the touchscreen  50 . The touchscreen  50  is adhered to the LCD module  64  using an adhesive  62 . 
         [0040]    According to the present disclosure, it is advantageous that the nanoscale grid patterns can be uniformly formed throughout a wide area of the transparent substrate. 
         [0041]    Also, according to the present disclosure, it is advantageous that the nanoscale metal layer as well as the aforesaid grid patterns can be also uniformly formed on the transparent substrate, thereby enabling the transparent substrate having electrical conductivity equal to ITO to be provided at a low cost. 
         [0042]    In addition, the master mold used in the present disclosure is recyclable until it is damaged, causing economical advantages such as the reduction of a raw material charge and a production cost. 
         [0043]    Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
         [0044]    Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.