Abstract:
An electrode structure for a touchscreen is provided. The electrode structure includes a flexible substrate and a plurality of electrode lines, wherein the electrode line includes a first adhesive layer, a second adhesive layer, a conductive layer, a first resist layer and a second resist layer. Through the configuration above, the electrode structure of the present application adheres the flexible substrate strongly by the first adhesive layer, and the second adhesive layer strengthen the adhesion between the first adhesive layer and the conductive layer, so that the conductive layer may be firmly adhered to the flexible substrate, even change the shape of the substrate, the electrode lines are not easy to fall off. The present invention also provides an electrode structure for scattering the reflective metallic luster to make observer imperceptible and reduce the backlight interference.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The instant disclosure relates to an electrode structure for touchscreen; in particular, to an electrode structure for a flexible touch panel. 
         [0003]    2. Description of Related Art 
         [0004]    Conventional touch panel generally use indium tin oxide (ITO) to form the electrodes to make the electrodes imperceptible. However, with the gradual development to the large-size touch panel, some defects of ITO electrodes are emerged such as high resistance, slow response and etc. Therefore, the industry has been trying to use thin metal wires to form the electrodes. 
         [0005]    In general, the touch panel using metal conductor as the electrodes often occurs the electrodes peeling due to the bad adhesion between the metal conductor and the common substrate, thereby affecting the performance of the touch panel. If applied to the flexible touch panel, it will exacerbate the occurrence of electrode peeling because the substrate is frequently deformed by the change of the environmental conditions. 
         [0006]    In addition, the metal conductor is liable to produce metallic luster and be observed easily by the human eyes. Therefore, it is the goal of this industry must strive to develop a steady and invisible electrode structure for a flexible touch panel in conjunction with the imperceptibleness at the same time. 
       SUMMARY OF THE INVENTION 
       [0007]    The object of the instant disclosure is to provide an electrode structure for touchscreen which can be attached to flexible substrate firmly and reduce metallic luster at the same time. 
         [0008]    The instant disclosure is to provide an electrode structure for touchscreen comprising a flexible substrate and a plurality of electrode lines set on the flexible substrate, wherein the electrode lines includes a first adhesive layer set on the flexible substrate, a second adhesive layer set on the first adhesive layer, a conductive layer set on the second adhesive layer and a first resist layer set on the conductive layer. 
         [0009]    According to an embodiment of the instant disclosure, the electrode lines may further comprise a second resist layer which at least cover side of the conductive layer and also can cover the first resist layer, the conductive layer, the second adhesive layer and the first adhesive layer on the flexible substrate entirely. The second resist layer can reflect the light to different angles to make human eye not come into contact with reflected light, thereby achieve the antireflection effect. 
         [0010]    In the instant disclosure, the first adhesive layer is used to enhance the adhesion to the flexible substrate, and the second adhesive layer is used to enhance the adhesion between the conductive layer and the first adhesive layer. 
         [0011]    By the above configuration, the instant disclosure can produce a strong adhesion to the flexible substrate through the first adhesive layer, along with the enhance to the adhesion between the conductive layer and the first adhesive layer through the second adhesive layer, thereby the conductive layer can be firmly adhered to the flexible substrate even if the substrate shape changes, the electrodes are not easy to fall off. Furthermore, by controlling the etching rate of each layer to produce the electrode structure with a cascading surface, it can further scatter the light to reducing the visibility. 
         [0012]    In order to further understand the instant disclosure, the following embodiments and illustrations are provided. However, the detailed description and drawings are merely illustrative of the disclosure, rather than limiting the scope being defined by the appended claims and equivalents thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a sectional drawing of an electrode structure in accordance with first embodiment of the instant disclosure; 
           [0014]      FIG. 2  is a sectional drawing of an electrode structure in accordance with second embodiment of the instant disclosure; 
           [0015]      FIG. 3  is a sectional drawing of an electrode structure in accordance with third embodiment of the instant disclosure; 
           [0016]      FIG. 4  is a sectional drawing of an electrode structure in accordance with fourth embodiment of the instant disclosure; 
           [0017]      FIG. 5  is a sectional drawing of an electrode structure in accordance with fifth embodiment of the instant disclosure; and 
           [0018]      FIG. 6  is a schematic diagram illustrating the electrode structure of the instant disclosure being applied on a touch panel. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    An electrode structure of the instant disclosure will be explained below through the embodiments. It has to be mentioned, the embodiments of the present invention are not intended to limit the present invention implementing in any specific environment, applications, or particular manner as described below. Therefore, the description of the embodiments only explains the purpose of the invention, not to limit the present invention. 
         [0020]    Please refer to  FIG. 1  as a sectional drawing of an electrode structure in accordance with first embodiment of the instant disclosure. In this embodiment, the electrode structure of the instant disclosure comprises a flexible substrate  11  and a plurality of electrode lines  19  (only one line illustrated in  FIG. 1 ), and in practice, the electrode lines  19  can be set on the flexible substrate  11  in parallel. Wherein the electrode lines  19  includes a first adhesive layer  12  set on the flexible substrate  11 , a second adhesive layer  13  set on the first adhesive layer  12 , a conductive layer  14  set on the second adhesive layer  13  and a first resist layer  15  set on the conductive layer  14 . 
         [0021]    In detail, the first adhesive layer  12  covers on the flexible substrate  11  to improve the adhesion to the flexible substrate  11  and with the effect of anti-reflective, anti-interference, anti-rainbow pattern, anti-abrasion, anti-scratch and enhance the comfort to human eyes. The second adhesive layer  13  covers on the first adhesive layer  12  to improve the adhesion between the conductive layer  14  and the first adhesive layer  12  and maintains the total conductivity of the electrode lines  19 . The conductive layer  14  covers on the second adhesive layer  13  to keep conduct. The first resist layer  15  which has better corrosion resistance than the conductive layer  14  covers on the conductive layer  14  to prevent the conductive layer  14  from lateral etching severely thereby the electrode lines  19  can retain a normal width. 
         [0022]    As a whole, the first adhesive layer  12  can form a strong adhesion with the flexible substrate  11  along with enhance of the adhesion between the conductive layer  14  and the first adhesive layer  12  by the second adhesive layer  13 . By this double-layer structure, the conductive layer  14  can be firmly adhered to the flexible substrate  11  with not easy falling off and have the effect of anti-reflective, anti-interference, anti-rainbow pattern, anti-abrasion, anti-scratch and improve the comfort to human eyes. The first resist layer  15  can postpone the oxidation or corrosion to the metal electrode. 
         [0023]    To achieve the above effect, the material to form the flexible substrate  11  may comprise one of the groups consisting of PET, PEI, PPSU, PI and its complex. 
         [0024]    Furthermore, the material to form the first adhesive layer  12  may comprise one of the groups consisting of polymer, oxide, metal and its complex, in detail, the polymer is used for improving the adhesion between the first adhesive layer  12  and the flexible substrate  11 ; the oxide is used for the anti-reflective, anti-interference, anti-rainbow pattern, anti-abrasion and anti-scratch; the metal is used for improving the adhesion between the first adhesive layer  12  and the second adhesive layer  13 . The polymer may comprise one of the groups consisting of acrylic, PET, PEI, PPSU, PI, PEDOT, polyaniline, polypyrrole and its complex; the oxide could be amorphous or polycrystalline oxide film or powder which may comprise one of the groups consisting of titanium oxide, tantalum oxide, silicon oxide, aluminum oxide and its complex; the metal may comprise copper, silver, aluminum, molybdenum, nickel, chromium, tungsten, titanium, silicon, tin, zinc, iron and its alloys. It should be emphasized, the above polymer, oxide and metal all can use individually or be mixed in two/three material to form complex, for example: a complex with polymer and oxide, a complex with polymer and metal, a complex with oxide and metal, a complex with polymer, oxide and metal. If the complex is used, the ratio range of polymer is between 10-90%, of oxide is between 10-90% and of metal is between 10-90%. The oxide also could be a poly-layer complex, in an embodiment, titanium oxide with 900 nm in thickness and silicon oxide with 100 nm in thickness can be chosen. Additionally, as a whole, the thickness of the first adhesive layer  12  is preferred to between 0.001 μm and 1 μm; the reflectivity of the first adhesive layer  12  is between 1% and 50% and is preferred under 30%. 
         [0025]    In the instant disclosure, the material to form the second adhesive layer  13  may comprise one of the groups consisting of copper, silver, molybdenum, nickel, chromium, tungsten, titanium, tin, zinc, aluminum, iron and its alloys, and the thickness of the second adhesive layer  13  is preferred between 0.001 μm and 1 μm. The reflectivity of the second adhesive layer  13  is between 1% and 50% and is preferred under 30%. Additionally, as a whole, the total reflectivity of the first adhesive layer  12  and the second adhesive layer  13  is preferred under 30%. 
         [0026]    In the instant disclosure, the material to form the conductive layer  14  may comprise one of the groups consisting of copper, gold, silver, aluminum, tungsten, iron, nickel, chromium, titanium, molybdenum, tin, zinc and its alloys, and the thickness of the conductive layer  14  is preferred between 0.001 μm and 5 μm. 
         [0027]    To achieve the optimizing of adhesion and conductivity, if the conductive layer  14  is formed with pure metal, the material of the second adhesive layer  13  contains the pure metal over than 50% and the material of the first adhesive layer  12  contains the pure metal less than 50%. In an embodiment, the conductive layer  14  could be straight copper wires, the first adhesive layer  12  could be a nickel-copper-chromium-iron alloy with the composition ratio of 60:30:10:0 or 80:10:5:5 or a nickel-tungsten alloy with the composition ratio of 50:50, and the first adhesive layer  12  also could contain other trace elements such as silicon, phosphorous and etc; the second adhesive layer  13  could be a copper-nickel-chromium alloy with the composition ratio of 60:30:10 or a copper-nickel-tungsten alloy with the composition ratio of 60:20:20, and the second adhesive layer  13  also could contain other trace elements such as silicon, phosphorous and etc. 
         [0028]    In the instant disclosure, the material to form the first resist layer  15  may comprise one of the groups consisting of copper, silver, aluminum, molybdenum, nickel, chromium, tungsten, titanium, silicon, tin, zinc, iron, and its alloys, and the thickness of the first resist layer  15  is preferred between 0.001 μm and 1 μm in an embodiment. The reflectivity of the first resist layer  15  is between 1% and 50% and is preferred under 30%. 
         [0029]    During the process to manufacturing the electrode structure of the instant disclosure, a cascading surface (as shown in  FIG. 1 ) can be formed with the first adhesive layer  12 , the second adhesive layer  13 , the conductive layer  14  and the first resist layer  15  on the flexible substrate  11  through controlling the etching proportion of the individual layer, and the cascading surface is an irregular surface so when the light reflected from the electrode, the reflective light will be scattered to different angles to make the electrode structure imperceptible for human eyes. 
         [0030]      FIG. 2  is a sectional drawing of an electrode structure in accordance with second embodiment of the instant disclosure. In the instant disclosure, the electrode lines  19  may further comprise a second resist layer  26  set on the first resist layer  15  and at least cover the side of the conductive layer  14 , if need be, the electrode lines  19  can entirely cover the first resist layer  15 , the conductive layer  14 , the second adhesive layer  13  and the first adhesive layer  12  on the flexible substrate  11 . The second resist layer  26  covers the first resist layer  15  to improve the corrosion resistance of the conductive layer  14 , to reduce the chance of foreign body rubbing metal electrodes to damage and lower the front and side reflective of metal electrodes. 
         [0031]    In the instant disclosure, the material to form the second resist layer  26  may comprise one of the groups consisting of oxide, polymer, carbon and its complex. The oxide may comprise silicon oxide, titanium oxide, aluminum oxide and its complex; the polymer may comprise PEDOT, polyaniline, polypyrrole and its complex. If the complex is utilized, the ratio of the polymer is 10-90% and the oxide is 10-90%. Additionally, as a whole, the thickness of the second resist layer  26  is preferred between 0.001 μm and 1 μm. The reflectivity of the second resist layer  26  is between 1%-50% and is preferred under 30%. Additionally, as a whole, the total reflectivity of the first resist layer  15  and the second resist layer  26  is preferred under 30%. 
         [0032]      FIG. 3  is a sectional drawing of an electrode structure in accordance with third embodiment of the instant disclosure.  FIG. 4  is a sectional drawing of an electrode structure in accordance with fourth embodiment of the instant disclosure. The different between  FIG. 3 ,  FIG. 4  and  FIG. 2  is that the second resist layer  36  is a thin layer with a cascading surface in  FIG. 3 ; the second resist layer  46  includes a granular surface and the diameter of the granule thereon is less than 900 nm and is preferred between 300 nm and 800 nm in  FIG. 4 ; the second resist layer  26  is a thin layer with curved surface in  FIG. 2 . In addition to the second resist layer  26 ,  36 ,  46  prevent corrosion of the electrodes, but also have the effect to reduce reflective of metal electrodes.  FIG. 5  is a sectional drawing of an electrode structure in accordance with fifth embodiment of the instant disclosure. Compared to  FIG. 5  and  FIG. 2 , the second resist layer  26 ,  56  both include curved thin layer in electrode structure but the different to  FIG. 5  and  FIG. 2  is that the first adhesive layer  52 , the second adhesive layer  53 , the conductive layer  54 , the first resist layer  55  all have irregular and rough surfaces, so that the reflective effect of metal electrodes can further be reduced. 
         [0033]    It should be mentioned that the materials and the preferred thickness described in the above components are only to detail the effect of each component and the achievement to reach, not to limit the instant disclosure, as long as the same effect can be achieved, the materials and thickness are not be limited here. 
         [0034]    Next refer to  FIG. 6 , is a schematic diagram illustrating the electrode structure of the instant disclosure being applied on a touch panel. The general situation in practical application to the flexible substrate  11  and the plurality of electrode lines  19  as shown in the drawing, the electrode lines  19  on the two surfaces of the flexible substrate  11  are insulated overlapping to each other, and the capacitor value is detecting when the electrode lines  19  is conduction. It should be emphasized, the electrode lines  19  protrude over the flexible substrate  11  as shown in Fig. is for convenience descriptions and are not actual situation. 
         [0035]    In summary, the instant disclosure provides a electrode structure for touchscreen which produces a strong adhesion to the flexible substrate  11  through the first adhesive layer  12 , along with the enhance to the adhesion between the first adhesive layer  12  and the conductive layer  14  through the second adhesive layer  13 , thereby the electrode lines  19  can be firmly adhered to the flexible substrate  11 . Furthermore, the first resist layer  15  postpones the oxidation or corrosion to the conductive layer  14 , the second resist layer  26 ,  36 ,  46 ,  56  at least cover the side of the conductive layer  14 , this two protection mechanisms can effectively prevent the electrode contacts form oxidation or corrosion and prolong the durability. by controlling the etching rate of each layer to produce the electrode structure with a cascading surface, it can further scatter the light to reducing the visibility. Due to a cascading surface included in the electrode structure of the instant disclosure, the reflective of the metal electrodes will be reduced, superadded forming the second adhesive layer  13  and the second resist layer  26 ,  36 ,  46 ,  56  further having the effect of anti-reflective, anti-interference, anti-rainbow pattern, to reach vision comfortable. 
         [0036]    The figures and descriptions supra set forth illustrated the preferred embodiments of the instant disclosure; however, the characteristics of the instant disclosure are by no means restricted thereto. All changes, alternations, combinations or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the instant disclosure delineated by the following claims.