Abstract:
A micro-light emitting diode (micro-LED) display device includes a substrate and a micro-LED. The substrate has at least one first metal layer. The micro-LED includes a light emitting structure, at least one second metal layer, at least one reflective layer, and a dielectric layer with an opening. The second metal layer forms a eutectic system or soldering contact with the first metal layer. The reflective layer is disposed between the light emitting structure and the second metal layer, and a eutectic point of the eutectic system or soldering point is lower than a melting point of the reflective layer. The dielectric layer is disposed between the light emitting structure and the reflective layer

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This application claims priority to Chinese Application Serial Number 201510116749.7, filed Mar. 18, 2015, which is herein incorporated by reference. 
       FIELD OF INVENTION 
       [0002]    The present disclosure relates to a touch technology. More particularly, the present disclosure relates to a touch panel and a fabrication method thereof. 
       DESCRIPTION OF RELATED ART 
       [0003]    In the present market of various consumer products, touch panels have been widely applied in portable electronic products, such as smartwatches, smartphones, tablet personal computers, notebook personal computers, etc., as the human machine interface (HMI). In addition, since the present electronic products are designed to be light, thin, short, and small, the space accommodating the input device (e.g. button) on the product has become smaller and smaller. As a result, with the trend of perusing user-friendly design of the tablet personal computers, touch panels have become one of the critical components in the portable products. 
         [0004]    A touch panel may be substantially divided to a visible area and a non-visible area. The visible area is designed to have a touch function to sense touch inputs of users, and the non-visible area provides the position for accommodating the peripheral designed lines. The non-visible area is usually opaque for preventing users from seeing the line configurations of the touch panel. As a result, the non-visible area is usually designed to have a light-shielding structure, which is not necessary for the visible area. Therefore, due to the light-shielding structure, a boundary portion of the visible area and the non-visible area usually has a rise on the surface feature. In the procedure of the patterning process, the rise on the surface feature may cause the accumulation of resists, which may block the unpatterned sensing electrodes from being etched effectively, creating an electrical short circuit among the sensing electrodes, and reducing the fabrication yield of the touch panels. 
       SUMMARY OF THE INVENTION 
       [0005]    One technical aspect of the present disclosure provides a touch panel. 
         [0006]    According to one or more embodiments of the present disclosure, the touch panel includes cover plate, shielding layer, and a first sensing structure. The cover plate has a visible area and a non-visible area, in which the non-visible area surrounds the visible area. The shielding layer is configured to define the non-visible area. The first sensing structure includes plural first sensing electrodes, and the first sensing electrodes are disposed in the visible area and at least a part of the non-visible area. Any two adjacent first sensing electrodes in the visible area have a first pitch therebetween, and any two adjacent first sensing electrodes at a boundary portion of the visible area and the non-visible area have a second pitch therebetween, in which the second pitch is greater then the first pitch. 
         [0007]    Another technical aspect of the present disclosure provides a method for fabricating a touch panel. 
         [0008]    The method for fabricating a touch panel includes providing a cover plate; forming a shielding layer; and forming a patterned first sensing structure. The cover plate has a visible area and a non-visible area, in which the non-visible area surrounds the visible area. The shielding layer is formed in the non-visible area. The patterned first sensing structure is formed in the visible area and at least a part of the non-visible area, in which the first sensing structure includes plural first sensing electrodes. Any two adjacent first sensing electrodes in the visible area have a first pitch therebetween, and any two adjacent first sensing electrodes at a boundary portion of the visible area and the non-visible area have a second pitch therebetween, in which the second pitch is greater then the first pitch. 
         [0009]    A rise on the surface feature at the changing position (e.g. the boundary portion described above) may reduce the fabrication yield of the touch panel may. For example, in the procedure of forming a patterned sensing structure (including a first sensing structure and a second sensing structure), a problem of accumulation of resists may exist at the boundary portion of the visible area and the non-visible area, thereby blocking the sensing structure from being etched effectively. As a result, by designing the adjacent sensing electrodes (including a first sensing electrode and a second sensing electrode) at the boundary portion to have a larger pitch therebetween than those at the other positions, the electrical short circuit resulting from the imperfection in the etching of the sensing structure among the sensing electrodes can be prevented, thereby improving the fabrication yield rate of the touch panels. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The disclosure can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows: 
           [0011]      FIG. 1  is a top view of a touch panel according to an embodiment of the present disclosure. 
           [0012]      FIG. 2  is a bottom view of the region A of  FIG. 1 . 
           [0013]      FIG. 3  is a cross-sectional view of the segment  3  of  FIG. 2 . 
           [0014]      FIG. 4  is an enlarged view of the region B of  FIG. 2 . 
           [0015]      FIG. 5  is a bottom view of the region A of another embodiment of  FIG. 1 . 
           [0016]      FIG. 6  is a bottom view of the region C of  FIG. 1 . 
           [0017]      FIG. 7  is a cross-sectional view of the segment  7  of  FIG. 6 . 
           [0018]      FIG. 8  is an enlarged view of the region D of  FIG. 6 . 
           [0019]      FIG. 9  is a cross-sectional view of a touch panel according to another embodiment of the present disclosure, and the profile position of  FIG. 9  is the same as that of  FIG. 3 . 
           [0020]      FIG. 10  to  FIG. 12  are continuous schematic views of patterning a first sensing structure according to one or more embodiments of the present embodiments. 
           [0021]      FIG. 13  is a schematic view of patterning a second sensing structure according to one or more embodiments of the present embodiments. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    The following embodiments are disclosed with accompanying diagrams for detailed description. For illustration clarity, many details of practice are explained in the following descriptions. However, it should be understood that these details of practice do not intend to limit the present disclosure. That is, these details of practice are not necessary in parts of embodiments of the present disclosure. Furthermore, for simplifying the drawings, some of the conventional structures and elements are shown with schematic illustrations. 
         [0023]      FIG. 1  is a top view of a touch panel  10  according to an embodiment of the present disclosure. As shown in  FIG. 1 , the touch panel  10  includes a cover plate  100 . The cover plate  100  has a visible area VA and a non-visible area NA. In the embodiment of  FIG. 1 , the non-visible area NA is disposed at the four sides of the visible area VA, and the non-visible area NA surrounds the visible area VA. To be specific, the touch panel  10  may include a shielding layer  130  formed on the cover plate  100 . The cover plate  100  can be made of transparent materials, such as glass, polyethyleneterephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PMMA), or other polymeric materials. The shielding layer  130  can be made of opaque materials, such as black photoresist, and is configured to define the non-visible area NA on the cover plate  100 . That is, the shielding layer  130  is disposed in the non-visible area NA, light can not pass through the shielding layer  130 , and therefore, the associated lines of the touch panel  10  can be disposed in the non-visible area NA, thereby the associated lines are prevented from being perceived by users and affecting the appearance of the displays. The edge of the shielding layer  130  can also be configured to define the non-visible area NA and the visible area VA. 
         [0024]      FIG. 2  is a bottom view of the region A of  FIG. 1 . As shown in figure, the touch panel  10  includes a first sensing structure  110  and at least a conductive line  170 . The conductive line  170  is disposed in the non-visible area NA. The first sensing structure  110  includes plural first sensing electrodes  111 , and the plural first sensing electrodes  111  are disposed in the visible area VA and at least a part of the non-visible area NA. To be specific, the first sensing electrodes  111  can be made of transparent conductive materials, and the visible area VA cab be covered by the first sensing electrodes  111  for detecting a touch input of the users. For example, in some embodiments, the plural first sensing electrodes  111  can be configured to receive a drive signal from the conductive line  170 , or to transmit a detected signal to the conductive line  170 . In some embodiments, the plural first sensing electrodes  111  can receive the drive signal from the conductive line  170  and then transmit the detected signal to the conductive line  170 . An end of one of the first sensing electrodes  111  arranged along the same axis is crossing the visible area VA and the non-visible area NA and is electrically connected to the conductive line  170 . As the embodiments shown by  FIG. 2 , among the first sensing electrodes  111  arranged along the same axis, an end of one of the first sensing electrodes  111  extends into the non-visible area NA and is electrically connected with the conductive line  170 . As a result, sensing signals detected by the plural first sensing electrodes  111  can be transmitted to processing units (not shown) by the conductive line  170  for calculating the touch position of users. 
         [0025]      FIG. 3  is a cross-sectional view of the segment  3  of  FIG. 2 , in which the profile position of the  FIG. 3  is crossing the visible area VA and the non-visible area NA. As shown in  FIG. 3 , the cover plate has a bottom surface  110 , and the shielding layer  130  covers the bottom surface  110  to form the non-visible area NA of the cover plate  110 . The first sensing electrodes  111  covers the bottom surface  101  of the cover plate  100  corresponding to the visible area VA, while the first sensing electrodes  111  extend to the non-visible area to cover a part of the shielding layer  130 . That is, the first sensing electrodes  111  is crossing the visible area VA and the non-visible area NA for ensuring a touch input of a user at the edge of the visible area VA can also be detected by the touch panel  10 . As a result, in the embodiment of  FIG. 3 , since the shielding layer  130  is disposed in the non-visible area NA and having a height H 1 , when the first sensing electrodes are crossing the visible area VA and the non-visible area NA, a rise on the surface feature is generated. In other words, there is a height difference ΔH 1  between a surface of the first sensing electrodes  111  in the visible area VA and a surface of the first sensing electrodes  111  in the non-visible area NA. The height difference ΔH 1  makes the fabrication yield of the touch panel  10  easily decreases. For example, in the procedure of the fabrication process of the touch panel  10 , it is necessary to perform a patterning process for forming plural first sensing electrodes  111 . In the procedure of the patterning process, resists are easily accumulated at the position of the height difference ΔH 1 , which blocks the unpatterned first sensing electrodes  111  from being etched effectively, resulting in a failure in the patterning process, and a reduction of the fabrication yield of touch panel  10 . 
         [0026]      FIG. 4  is an enlarged view of the region B of  FIG. 2 . As shown in figure, there is a boundary portion  120  between the visible area VA and the non-visible area NA. The boundary portion  120  is substantially the region from an area having no height difference ΔH 1  to an area having the height difference ΔH 1 , and also referred to the region where the rise on the surface feature of the first sensing electrodes  111  of is located. Viewing from the etching line (between the first sensing electrodes  111 ), the boundary portion  120  is substantially at the position of an edge L 1  of shielding layer  130 . In some embodiments, the edge L 1  of the shielding layer  130  is taken as a centerline, the boundary portion  120  includes a range extending a determined distance (e. g. 0.4, 0.5, or 0.6 millimeter) toward two opposite sides (toward the center of the cover plate  100  and the edge of the cover plate  110 , which are the X and −X direction in  FIG. 4 ) from the centerline.  FIG. 4  depicts plural first sensing electrodes  111  that have been patterned by the patterning process, in which any two adjacent first sensing electrodes  111  in the visible area VA have a first pitch D 1  therebetween, and any two adjacent first sensing electrodes  111  at a boundary portion  120  of the visible area VA and the non-visible area NA have a second pitch D 2  therebetween. In the embodiment of  FIG. 4 , wherein the second pitch D 2  is greater then the first pitch D 1 . Therefore, by designing the second pitch D 2  to be greater than the first pitch D 1 , in the procedure of patterning plural first sensing electrodes  111 , an incomplete etch can be prevented from occurring. 
         [0027]    More detail, at the position of the boundary portion  120 , the problem of the accumulation of resists is more serious at an edge of the second pitch D 2  adjoining the first sensing electrodes  111  than that at a center of the second pitch D 2 . As a result, in the procedure of patterning the plural first sensing electrodes  111 , if the second pitch D 2  is designed to be greater than the first pitch D 1 , the problems of incomplete etch at the edge of the second pitch D 2  adjoining the first sensing electrodes  111  can be prevented, and the resulting electrical short circuit between two adjacent first sensing electrodes  111  can be prevented from occurring. 
         [0028]      FIG. 5  is a bottom view of the region A of another embodiment of  FIG. 1 .  FIG. 5  is similar to  FIG. 2 , but the difference is that in the non-visible area NA, the shielding layer  130  is disposed on the cover plate  100 , the conductive line  170  is disposed on the shielding layer  130 , and a insulating layer  171  is disposed on the shielding layer  130  in the area where the conductive line  170  is not disposed. The insulating layer  171  can be made of various nonconductive materials, such as polyimide (PI), silicon oxide (SiO 2 ), silicon nitride (SiN), silicon carbonitride (SiCN), silicon carbide (SiC). Therefore, when the sensing electrodes (such as the first sensing electrodes  111 ) are disposed, the insulating layer  171  is disposed between the shielding layer  130  and the first sensing electrodes  111 , and the insulating layer  171  is also disposed between a part of the conductive line  170  and the first sensing electrodes  111 , thereby preventing the sensing electrodes from being in direct contact with the conductive line  170  which the sensing electrodes is not corresponding to. In this embodiment, the boundary portion  120  includes a range from an edge of the shielding layer  130  to an edge of the insulating layer  170 . In some embodiments, the boundary portion  120  can be defined as a range extending a determined distance (e. g. 0.4, 0.5, or 0.6 millimeter) in a normal direction (such as the X direction toward the center of the cover plate  100  in  FIG. 5 ) of the edge L 1  of the shielding layer  130 , or extending a determined distance (e. g. 0.4, 0.5, or 0.6 millimeter) in a normal direction (such as the X direction toward the center of the cover plate  100  in  FIG. 5 ) of the edge L 2  of the insulating layer  171 . 
         [0029]    Next, referring back to  FIG. 1 . In the embodiment of  FIG. 1 , the shielding layer  130  can includes at least one hollow-out pattern  135 . As shown in figure, for example, the hollow-out pattern  135  can be a pattern of a return key or a pattern of home key. In this embodiment, there are also sensing electrodes at the position of the hollow-out pattern  135 . Therefore, the electronic devices utilizing the touch panel  10  of the present embodiment can totally get rid of the traditional physical button structure. 
         [0030]    To be specific, referring to  FIG. 6 , which is a bottom view of the region C of  FIG. 1 . As shown in figures, the touch panel  10  can further include a second sensing structure  140 . The second sensing structure  140  includes plural second sensing electrodes  141 . In the embodiment of  FIG. 6 , the second sensing electrodes  141  are made of transparent conductive materials, and the second sensing electrodes  141  are disposed in the non-visible area NA. The second sensing electrodes  141  at least partially cover the hollow-out pattern  135 . In this way, when users touch the hollow-out pattern  135  of  FIG. 1 , the second sensing electrodes  141  can detect a touch input of the users. 
         [0031]    More specifically, take the embodiment of  FIG. 6  as example, the plural second sensing electrodes  141  can divided into electrodes  141   a , electrodes  141   b , and electrodes  141   c , in which the electrodes  141   a  can receive a drive signal from the conductive line  170 , and the electrodes  141   b  can transmit a signal generated by the touching on the touch panel  10  to the conductive line  170 ; alternatively, the electrodes  141   b  can receive a drive signal from the conductive line  170 , and the electrodes  141   a  can transmit a signal generated by the touching on the touch panel  10  to the conductive line  170 . In some embodiments, the electrodes  141   a  and electrodes  141   b  can receive drive signals from the conductive line  170 , and then transmit signals generated by the touching on the touch panel  10  to the conductive line  170 . The electrodes  141   c  are void electrodes and configured to establish optical match between the electrodes  141   a  and the electrodes  141   b , so that the lines of the electrodes  141   a  and the electrodes  141   b  are uneasily perceived by the naked eye. In addition, the electrodes  141   c  are disposed between the electrodes  141   a  and the electrodes  141   b  for preventing the crosstalk between the electrodes  141   a  and the electrodes  141   b  from influencing the sensitivity. The electrodes  141   a  can be mutually electrically connected along the axis A through a bridging line  180   a , and the electrodes  141   b  can be mutually electrically connected along the axis B through a bridging line  180   b , in which the bridging line  180   a  and the bridging line  180   b  are mutually isolated. It should be understood that, the patterns of the second sensing electrodes  141  are merely used as an example. In other embodiments, the second sensing electrodes  141  can have a pattern or structure known by one with ordinary skill in the art. 
         [0032]      FIG. 7  is a cross-sectional view of the segment  7  of  FIG. 6 . Reference is now made to  FIG. 6  and  FIG. 7 . There is no shielding layer  130  at the position of the hollow-out pattern  135  since it is in the non-visible area VA. Therefore, in the non-visible area NA, there is a height difference ΔH 2  between a surface of the second sensing electrodes  141  in the hollow-out pattern  135  and a surface of the second sensing electrodes  141  out of the hollow-out pattern  135 . Similar to the height difference ΔH 1  in  FIG. 3  easily blocking the first sensing electrode  111  from being etched effectively, the height difference ΔH 2  also easily blocks the second sensing electrode  141  from being etched effectively, and thereby reducing the fabrication yield of the touch panel  10 . 
         [0033]      FIG. 8  is an enlarged view of the region D of  FIG. 6 . In  FIG. 8 , plural second sensing electrodes  141  that have been patterned by the patterning process are depicted. As shown in figures, the hollow-out pattern  135  has an edge portion  190 . The edge portion  190  of the hollow-out pattern  135  is substantially the region in  FIG. 7  from an area having no height difference ΔH 2  to an area having the height difference ΔH 2 , and also referred to the region where the rise on the surface feature of the second sensing electrodes  141  of is located. To be specific, the edge L 1  of the shielding layer  130  is taken as a centerline, the edge portion  190  includes a range extending a determined distance (e. g. 0.4, 0.5, or 0.6 millimeter) toward two opposite sides (toward the center of the cover plate  100  and the edge of the cover plate  110 , which are the X and −X direction in  FIG. 8 ) from the centerline. In the embodiment of  FIG. 8 , out of the hollow-out pattern  135 , any two adjacent second sensing electrodes  141  have a third pitch D 3  therebetween. At the edge portion  190  of the hollow-out pattern, any two adjacent second sensing electrodes  141  have a fourth pitch D 4  therebetween, wherein the fourth pitch D 4  is greater then the third pitch D 3 . As a result, by designing the fourth pitch D 4  to be greater then the third pitch D 3 , in the procedure of patterning plural second sensing electrodes  141 , the incomplete etch can be prevented from occurring. 
         [0034]    More detail, at the position of the edge portion  190 , the problem of the accumulation of resists is more serious at the edge of the fourth pitch D 4  adjoining the second sensing electrodes  141  than that at the center of the fourth pitch D 4 . As a result, in the procedure of patterning the plural second sensing electrodes  141 , if the fourth pitch D 4  is designed to be greater than the third pitch D 3 , the problems of incomplete etch at the edge of the fourth pitch D 4  adjoining the second sensing electrodes  141  can be prevented, and the resulting electrical short circuit between two adjacent second sensing electrodes  141  can be prevented from occurring. 
         [0035]    Referring to  FIG. 8 , in the hollow-out pattern  135 , any two adjacent second sensing electrodes  141  have a fifth pitch D 5  therebetween. In the embodiments of the present disclosure, the second sensing electrodes  141  in the hollow-out pattern  135  have less rise on the surface feature, the possibility of perceiving the etch line can be reduced when the fifth pith D 5  is smaller than the fourth pitch D 4 , and the possibility of electrical short circuits among the electrodes can be reduced when the fifth pith D 5  is greater than the third pitch D 3 , so the fifth pith D 5  in the hollow-out pattern  135  can be designed to be greater than or equivalent to the third pitch D 3 , or to be equivalent to or less than the fourth pitch D 4 , and the patterning result of the second sensing electrodes  141  would not be influenced. 
         [0036]    In some embodiments, a ink layer can be disposed on the second sensing structure  140  (between the second sensing structure  140  and the backlight module), and the ink layer can have colors and transmittance, so that the hollow-out pattern  135  can show corresponding colors. 
         [0037]      FIG. 9  is a cross-sectional view of a touch panel  20  according to another embodiment of the present disclosure, and the profile position of  FIG. 9  is the same as that of  FIG. 3 . As shown in figure, the difference between the present embodiment and the embodiment of  FIG. 3  is that, in the embodiment of  FIG. 3 , the first sensing electrodes  111  and the shielding layer  130  are all disposed on the cover plate  100 , but in the present embodiment, the first sensing electrodes  111  and the shielding layer  130  are disposed separately from the cover plate  100 . To be specific, for example, in the embodiment of  FIG. 3 , the touch panel  10  can be one-glass solution (OGS) touch panel, and in the embodiment of  FIG. 9 , the touch panel  10  can be the touch panel  20  with two layer of glass. 
         [0038]    More specifically, in the embodiment of  FIG. 9 , the touch panel can further include a substrate  150 . The substrate  150  can be made of transparent or opaque materials, such as glass, polyethyleneterephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PMMA), or other polymeric materials. The substrate  150  can have a loading surface  151  facing a bottom surface  101  of the cover plate  100 . The shielding layer  130  is disposed on at part of the loading surface  151  to form a non-visible area NA of the cover plate  100 . The first sensing electrodes  111  of the first sensing structure  110  cover a part of the shielding layer  130  and the loading surface  151  corresponding to the visible area. Since the first sensing structure  110  is crossing the visible area VA and the non-visible area NA, the first sensing structure  110  have a rise on the surface feature at the boundary portion of the visible area VA and the non-visible area NA. In view of this, similar to those shown in  FIG. 3 , by designing the second pitch D 2  greater than the first pitch D 1 , in the procedure of patterning plural first sensing electrodes  111 , an incomplete etch can be prevented from occurring. 
         [0039]    Similarly, in the structure of the touch panel  20  of  FIG. 2 , the second electrodes  141  are also formed on the loading surface  151  (not shown) of the substrate  150 . Likewise, if the second sensing electrodes  141  have a rise on the surface feature, which may result in the incomplete etch, as the structure of  FIG. 8 , the distance between the adjacent second sensing electrodes  141  can be designed to be greater than that at a flat portion (out of the hollow-out pattern  135  of  FIG. 8 ), thereby preventing the rise on the surface feature from affecting the fabrication yield of the touch panel  20 . 
         [0040]    For better understanding, following embodiments provides a method for fabricating a touch panel, and the method includes following steps:
       S 1 : providing a cover plate;   S 2 : forming a shielding layer; and   S 3 : forming a patterned first sensing structure.       
 
         [0044]    Referring to  FIG. 1 , at step S 1 , the cover plate has and defines a visible area VA and a non-visible area NA, in which the non-visible area NA surrounds the visible area VA. Next, at step S 2 , the shielding layer  130  is formed in the non-visible area NA. As shown in  FIG. 3 , if the touch panel  10  is a structure of one-glass solution, the shielding layer  130  can be formed on the bottom surface  101  of the cover plate  100 , and the first sensing structure  110  is formed on a part of the shielding layer  130  and the bottom surface  101  of the cover plate  100  corresponding to the visible area VA. As shown in  FIG. 9 , if the touch panel  20  is a structure of two layer of glass, the method for fabricating the touch panel  20  further includes providing a substrate  150 . In addition, the step of forming the shielding layer  130  can further include forming the shielding layer  130  on the loading surface  151  of the substrate  150 , and the first sensing structure  110  can be formed on a part of the shielding layer  130  and the loading surface  151  of the substrate  150  corresponding to the visible area VA. 
         [0045]    In some embodiments, for example, the cover plate  100  can be transparent glass material, but it should not limit the present disclosure. The shielding layer  130  can be made of opaque materials, such as black resist, and the shielding layer  130  can be formed in the non-visible area NA by imprinting or coating, but it should not limit the present disclosure. 
         [0046]    Referring to  FIG. 2 , at step S 3 , a patterned first sensing structure  110  can be formed in the visible area VA and at least the part of the non-visible area NA. To be specific, reference is made to  FIG. 10  to  FIG. 12 , which depict continuous schematic views of patterning the first sensing structure, in which the position depicted by  FIG. 10  to  FIG. 12  is similar to the position of  FIG. 3  to  FIG. 4  in the fabrication process. As shown in figures, the step of patterning the first sensing structure  110  can further include:
       S 3 . 1 : forming a first sensing electrode layer  111   a  in the visible area VA and at least the part of the non-visible area NA;   S 3 . 2 : coating a resist layer  160  on the first sensing electrode layer  111   a;      S 3 . 3 : forming plural first sensing electrode patterns  160   a  of the resist layer  160  on the first sensing electrode layer  111   a ; and   S 3 . 4 : etching the first sensing electrode layer  111   a  by utilizing the first sensing electrode patterns  160   a.          
 
         [0051]    As shown in  FIG. 10 , at step S 3 . 1 , the first sensing electrode layer  111   a  covers a surface (which is the bottom surface  101  of  FIG. 3 ) of the cover plate  100  corresponding to the visible area VA, and at least partially covers the shielding layer  130 . The first sensing electrode layer  111   a  can be made of transparent conductive materials, such as Indium Tin Oxide (ITO) and Indium Zinc Oxide (IZO). 
         [0052]    Next, as shown in  FIG. 11 , at step S 3 . 2 , the resist layer  160  can has a height H 2  at a flat portion of the visible area VA or the non-visible area NA. The resist layer  160  can has a height H 3  at the boundary portion  120  of the visible area VA and the non-visible area NA. Since the resist layer  160  is accumulated at the boundary portion  120  where a rise on the surface feature is located, the height H 3  at the boundary portion  120  is greater than the height H 2  at the flat portion, and therefore, in the following developing procedure, the resist layer  160  at boundary portion  120  is developed with an imperfection, and the underlying first sensing layer  111   a  is etched with an imperfection. 
         [0053]    Next, as shown in  FIG. 12 , at step S 3 . 3 , plural first sensing electrode patterns  160   a  are formed by patterning the resist layer  160 , such as the exposing and developing procedure. As shown in the figure, at the boundary portion  120 , the first sensing electrode patterns  160   a  have a first etch compensation pitch E 1  therebetween. To be specific, the value of the first etch compensation pitch E 1  is a sum of the value of the second pitch D 2  of  FIG. 4  and a first compensation value. As a region E shown in  FIG. 12 , since there may be a remaining resist layer  160  that is not completely developed (particularly, between at the edge portion of the first etch compensation pitch E 1  adjoining the first sensing electrode patterns  160   a ) at the boundary portion  120  between two adjacent first sensing electrode patterns  160   a , therefore, the etching effect at the boundary portion  120  of the first sensing electrode layer  111   a  is worse. Therefore, in the embodiment of  FIG. 12 , by enlarging the distance between two adjacent first sensing electrode patterns  160   a , in the subsequently etching the first sensing layer  111   a , it can be prevented that the electrical short circuit is produced between two adjacent first sensing electrodes  111  due to the imperfection in the etch process. 
         [0054]    In some embodiments, at the boundary portion  120 , an edge of the shielding layer  130  can have a slope. The first compensation value is proportional to the slope of the edge of the shielding layer  130 . To be specific, the shielding layer  130  refers to an incline of the shielding layer  130  close to the visible area VA, and the slope of the edge of the shielding layer  130  is the degree of the incline. That is, the greater the slope, the more serious the accumulation of the resist layer  160  at the edge of the shielding layer  130 , and the greater the value of the first compensation value. In practical applications, the first etch compensation pitch E 1  can be about 34 micrometers, in which the value of the second pitch can be about 30 micrometers, and the first compensation value can be about 4 micrometers, but it should not limit the scope of the present disclosure. 
         [0055]    Next, reference is made to  FIG. 3  and  FIG. 12 . At step S 3 . 4 , the plural patterned first sensing electrodes  111  can be formed by the first sensing electrode patterns  160   a  on the resist layer  160 . From  FIG. 12  and  FIG. 4 , it is known that due to the accumulation of the resist layer  160  at the boundary portion  120 , at the boundary portion  120 , the second pitch D 2  between the two adjacent first sensing electrodes  111  would be smaller than the first etch compensation pitch E 1 . 
         [0056]    In some embodiments, as shown in  FIG. 5 , in the non-visible area NA, an insulating layer is formed between the first sensing structure  110  and the shielding layer  130 , in which the boundary portion  120  includes a range from an edge L 1  of the shielding layer  130  to an edge L 2  of the insulating layer. 
         [0057]    Referring to  FIG. 1 , the step of forming a shielding layer  130  includes forming a hollow-out pattern  135 . As shown in  FIG. 1 , the hollow-out pattern  135  can be a pattern of a return key or a pattern of home key. In some embodiments, the hollow-out pattern  135  can be formed by lithography process, but it should not limit the present disclosure. 
         [0058]    Next, referring to  FIG. 6 . As shown in figure, in some embodiments, the method for fabricating the touch panel  10  can further include:
       S 4 : forming a patterned second sensing electrode structure  140 .       
 
         [0060]    To be specific, referring to  FIG. 13 , which depicts a schematic view of patterning a second sensing structure  140 . As shown in the figure, the step of patterning the second sensing structure  140  can further includes:
       S  4 . 1 : forming a second sensing electrode layer  140   a  in the non-visible area NA;   S  4 . 2 : coating a resist layer  160 ′ on the second sensing electrode layer  140   a;      S  4 . 3 : forming plural second sensing electrode patterns  160   a ′ of the resist layer  160 ′ on the second sensing electrode layer  140   a ; and   S  4 . 4 : etching the second sensing electrode layer  140   a  by utilizing the plural second sensing electrode patterns  160   a′.          
 
         [0065]    As shown in  FIG. 13 , at step S  4 . 1 , the second sensing electrode layer  140  at least partially covers the hollow-out pattern  135 . In some embodiments, the second sensing electrode layer  140   a  can be made of transparent conductive materials, such as Indium Tin Oxide (ITO) and Indium Zinc Oxide (IZO), and the second sensing electrode layer  140   a  and the first sensing electrode layer  111   a  can be formed by the same process. 
         [0066]    At step S 4 . 2 , the resist layer  160 ′ of  FIG. 13  and the resist layer  160  of  FIG. 11  can be formed by the same process. As shown in  FIG. 13 , the resist layer  160 ′ has a height H 4  at a flat portion in the hollow-out pattern  135  or out of the hollow-out pattern  135 . The resist layer  160 ′ can have a height H 5  at the edge portion  190  of the hollow-out pattern  135 . Since the resist layer  160 ′ is accumulated at the edge portion  190  where a rise on the surface feature is located, the height H 5  at the edge portion  190  is greater than the height H 4  at the flat portion. Therefore, in the follow developing procedure, the resist layer  160 ′ at the edge portion  190  is developed with an imperfection, and therefore the underlying second sensing layer  141   a  is etched with an imperfection. 
         [0067]    As a result, as the step S  4 . 3 , the second sensing electrode patterns  160   a ′ can have a second compensation pitch E 2  therebetween. To be specific, the value of the second etch compensation pitch E 2  is a sum of the value of the fourth pitch D 4  of  FIG. 8  and the second compensation value. As shown in the region F in  FIG. 13 , at the etch portion  190 , between two adjacent second sensing electrode patterns  160   a ′, since there may be a remaining resist layer  160  that is not completely developed (particularly, between at the edge portion of the second etch compensation pitch E 2  adjoining the second sensing electrode patterns  160   a ′), therefore, the etching effect of the second sensing electrode layer  140   a  is worse. As a result, in the embodiment of  FIG. 13 , by enlarging the distance between two adjacent second sensing electrode patterns  160   a ′, it can be prevented that the electrical short circuit is produced between two adjacent second sensing electrodes  141  due to the imperfection in the subsequent etch process. 
         [0068]    In some embodiments, at the etch portion  190 , an edge of the shielding layer  130  can have a slope. The second compensation value is proportional to the slope of the edge of the shielding layer  130 . In the practical applications, the second etch compensation pitch E 2  can be about 34 micrometers, in which the value of the fourth pitch D 4  can be about 30 micrometers, and the second compensation value can be about 4 micrometers, but it should not limit the scope of the present disclosure. 
         [0069]    Next, at step S 4 . 4 , the plural patterned second sensing electrodes  141  can be formed by the corresponding second sensing electrode patterns  160   a ′ of the resist layer  160 ′. From  FIG. 13  and  FIG. 8 , it is known that due to the accumulation of the resist layer  160 ′ at the etch portion  190 , at the etch portion  190 , the fourth pitch D 4  between the two adjacent second sensing electrodes  141  would be smaller than the second etch compensation pitch E 2 . 
         [0070]    In conclusion, the resist may accumulate at the changing position (such as the boundary portion and the edge portion) where the rise on the surface feature is located. As a result, in one or more embodiments of the present disclosure, at the changing position where the rise on the surface feature is located, the distance between two adjacent sensing electrodes (such as the first sensing electrodes and the second sensing electrode) is required to be greater than that at the flat portion, thereby reducing the possibility of electrical short circuits resulted from an imperfection in the etch process among the sensing electrodes (such as the first sensing electrodes and the second sensing electrodes), and increasing the fabrication yield of the touch panels. 
         [0071]    Although the present disclosure has been described in considerable detail with reference to certain embodiments thereof, it should not limit the present disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims.