Patent Publication Number: US-2015060254-A1

Title: Touch panel and manufacturing method thereof

Description:
This application claims the benefit of Taiwan application Serial No. 102131385, filed Aug. 30, 2013, the subject matter of which is incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The disclosure relates in general to a panel and a manufacturing method thereof, and more particularly to a touch panel and a manufacturing method thereof. 
     2. Description of the Related Art 
     As the development of the technology, varied inputting devices have been invented. For example, touch panels, handwriting panels, voice inputting devices, and gesture inputting devices are significantly developed on technology. 
     The touch panel can receive a touching signal from a finger or a stylus to generate a corresponding inputting signal. The touch panel can be configured to a display panel for a user to click or draw on patterns intuitively. Therefore, the touch panel has been widely used in varied electronic devices. 
     SUMMARY 
     The disclosure is directed to a touch panel and a manufacturing method thereof. Conductive electrodes and auxiliary electrodes are used for reducing the impedance of the touch panel and keeping the capacitance difference at a particular level, such that the touching efficiency can be improved. 
     According to a first aspect of the present disclosure, a touch panel is provided. The touch panel includes an insulating layer, a plurality of first conductive electrodes, a plurality of second conductive electrodes, a plurality of first auxiliary electrodes and a plurality of second auxiliary electrodes. The insulating layer has a first side, a second side opposite to the first side and a plurality of through holes. The first conductive electrodes are disposed on the first side of the insulating layer. The first conductive electrodes are arranged along a first direction and electrically connected with each other. The second conductive electrodes are disposed on the second side of the insulating layer. The second conductive electrodes are arranged along a second direction and electrically connected with each other. The first auxiliary electrodes are disposed on the second side of the insulating layer. The first auxiliary electrodes and the first conductive electrodes are electrically connected via part of the though holes. The second auxiliary electrodes are disposed on the first side of the insulating layer. The second auxiliary electrodes and the second conductive electrodes are electrically connected via another part of the though holes. 
     According to a second aspect of the present disclosure, a manufacturing method of a touch panel is provided. The manufacturing method of the touch panel includes the following steps. A plurality of first conductive electrodes and a plurality of second auxiliary electrodes are formed. The first conductive electrodes are arranged along a first direction and electrically connected with each other. An insulating layer is formed on the first conductive electrodes and the second auxiliary electrodes. The insulating layer has a plurality of through holes. A plurality of second conductive electrodes and a plurality of first auxiliary electrodes are formed on the insulating layer. The second conductive electrodes are arranged along a second direction and electrically connected with each other. The first auxiliary electrodes and the first conductive electrodes are electrically connected via part of the through holes. The second auxiliary electrodes and the second conductive electrodes are electrically connected via another part of the through holes. 
     The above and other aspects of the disclosure will become better understood with regard to the following detailed description of the non-limiting embodiment(s). The following description is made with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of a touch panel. 
         FIGS. 2A to 2C  illustrate a flow chart of a manufacturing method of the touch panel of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the touch panel of  FIG. 1  along a cutting line  3 - 3 . 
         FIG. 4  is a cross-sectional view of the touch panel of  FIG. 1  along a cutting line  4 - 4 . 
         FIGS. 5A to 5E  show several embodiments of a plurality of first connecters and a plurality of second connecters of  FIG. 1 . 
         FIGS. 6A to 11B  illustrate an experimental records of the impedance and the power loss according to different ratios of the cross-section of a plurality of connecters to that of the conductive electrodes. 
     
    
    
     DETAILED DESCRIPTION 
     Please referring to  FIGS. 1 and 2A  to  2 C,  FIG. 1  is a top view of a touch panel  100  and  FIGS. 2A to 2C  illustrate a flow chart of a manufacturing method of the touch panel  100  of  FIG. 1 . To simplify the description, the following description is focused on some elements of the touch panel  100  relating to the present invention, other elements, such as substrate and/or cover lens are not illustrated in the drawings. However, it should be understood that the substrate of the present invention includes a substrate separated from a display device or a substrate integrated within a display device, such as a color filter substrate of a liquid crystal display or an encapsulation plate of an organic light-emitting diodes display device. Moreover, the substrate or the cover lens can be covered with a patterned decoration layer having patterns, symbols or text. The touch panel  100  includes an insulating layer  110 , a plurality of first conductive electrodes  121 , a plurality of second conductive electrodes  122 , a plurality of first auxiliary electrodes  131 , a plurality of second auxiliary electrodes  132 , a plurality of first connecters  141  and a plurality of second connecters  142 . Due to the viewing angle,  FIG. 1  shows the second conductive electrodes  122 , the first auxiliary electrodes  131  and the insulating layer  110  by solid lines and shows the first connecters  141  and the second connecters  142  by dashed lines. The first conductive electrodes  121  and the second auxiliary electrodes  132  are hided and are not shown in the  FIG. 1 . 
     The first conductive electrodes  121  and the second auxiliary electrodes  132  are disposed on a first side  110   a  of the insulating layer  110 , such as the bottom surface of the insulating layer  110 . The second conductive electrodes  122  and the first auxiliary electrodes  131  are disposed on the second side  110   b  of the insulating layer  110 , such as the top surface of the insulating layer  110 . The insulating layer  110  has a plurality of through holes  110   c.  The first connecters  141  are disposed in part of the through holes  110   c  for electrically connecting the first conductive electrodes  121  and the first auxiliary electrodes  131 . The second connecters  142  are disposed in another part of the through holes  110   c  for electrically connecting the second conductive electrodes  122  and the second auxiliary electrodes  132 . 
     The stacking relationship among those elements can be illustrated via the manufacturing method of the touch panel  110 . Please referring to 
       FIG. 2A , firstly, a plurality of first conductive electrodes  121  and a plurality of second auxiliary electrodes  132  are formed on the substrate. The first conductive electrodes  121  are electrically connected and arranged along a first direction C1, such as Y axis, to form a plurality of strip structures. The second auxiliary electrodes  132  are arranged alone a second direction C2, such as X axis, and are separated. The first conductive electrodes  121  and the second auxiliary electrodes  132  are arranged in a matrix, and the first conductive electrodes  121  and the second auxiliary electrodes  132  are interlaced and are not located at the same row or the same column. 
     Then, please referring to  FIG. 2B , the insulating layer  110  is formed on the first conductive electrodes  121  and the second auxiliary electrodes  132 , and covers the substrate. Because the first conductive electrodes  121  and the second auxiliary electrodes  132  are covered by the insulating layer  110 , the first conductive electrodes  121  and the second auxiliary electrodes  132  are represented by dashed lines. Afterwards, the through holes  110   c  are formed on the insulating layer  110 . For example, an exposing and patterning process is performed on the locations of the insulating layer  110  corresponding to the first conductive electrodes  121  and the second auxiliary electrodes  132  to form the through holes  110   c.  The drawings are exemplified with two through holes  110   c  corresponding to each first conductive electrode  121  and each second auxiliary electrode  132 , but it is not limited thereto. 
     Then, please referring to  FIG. 2C , the second conductive electrodes  122  and the first auxiliary electrodes  131  are formed on the insulating layer  110 . The second conductive electrodes  122  are arranged along the second direction C2 and electrically connected with each other. The first auxiliary electrodes  131  are arranged along the first direction C1 and are separated. The second conductive electrodes  122  and the first auxiliary electrodes  131  are arranged in a matrix, and the second conductive electrodes  122  and the first auxiliary electrodes  131  are interlaced and are not located at the same row or the same column. The second conductive electrodes  122  extend to part of the through holes  110   c  to form the second connecters  142  for electrically connecting the second auxiliary electrodes  132  (shown in  FIG. 2A ). 
     The first auxiliary electrodes  131  extend to the part of the through holes  110   c  to form the first connecters  141  for electrically connecting the first conductive electrodes  121  (shown in  FIG. 2A ). 
     Please referring to  FIG. 3 ,  FIG. 3  is a cross-sectional view of the touch panel  100  of  FIG. 1  along a cutting line  3 - 3 . The cutting line  3 - 3  is parallel to the second direction C2. The second conductive electrodes  122  are arranged alone the second direction C2, so the second conductive electrodes  122  is continuously connected in the cross-sectional view along the cutting line  3 - 3 . The first conductive electrodes  121  are arranged alone the first direction C1 and are not arranged alone the second direction C2, so the first conductive electrodes  121  are discontinuous in the cross-sectional view along the cutting line  3 - 3 . 
     Please referring to  FIG. 4 ,  FIG. 4  is a cross-sectional view of the touch panel  100  of  FIG. 1  along a cutting line  4 - 4 . The cutting line  4 - 4  is parallel to the first direction C1. The first conductive electrodes  121  are arranged along the first direction C1, so the first conductive electrodes  121  are continuously connected in the cross-sectional view along the cutting line  4 - 4 . The second conductive electrodes  122  are arranged along the second direction C2 and not arranged along the first direction C1, so the second conductive electrodes  122  are discontinuous in the cross-sectional view along the cutting line  4 - 4 . 
     As shown in  FIG. 2A , regarding the detail structure of the first conductive electrodes  121 , the first conductive electrodes  121  are composed of a plurality of first enlarging portions  121   a  and a plurality of first narrowing portions  121   b.  Each first narrowing portion  121   b  connects two adjacent first enlarging portions  121   a  to from a strip structure. 
     As shown in  FIG. 2C , regarding the detail structure of the first auxiliary electrodes  131 , the first auxiliary electrodes  131  are composed of a plurality of second enlarging portions  131   a.  The first enlarging portions  131   a  are separated and overlap with the first enlarging portions  121   a  of the first conductive electrodes  121  (shown in  FIG. 2A ). 
     As shown in  FIG. 2C , regarding to the detail structure of the second conductive electrodes  122 , the second conductive electrodes  122  are composed of a plurality of third enlarging portions  122   a  and a plurality of second narrowing portions  122   b.  Each second narrowing portion  122   b  connects two adjacent second enlarging portions  122   a  to from a strip structure. 
     As shown in  FIG. 2A , regarding to the detail structure of the second auxiliary electrodes  132 , the second auxiliary electrodes  132  are composed of a plurality of fourth enlarging portions  132   a.  The fourth enlarging portions  132   a  are separated and overlap with the third enlarging portions  122   a  of the second conductive electrodes  122  (shown in  FIG. 2C ). 
     As shown in  FIG. 2C , two second enlarging portions  131   a  of the first auxiliary electrodes  131  are located at two sides of one second narrowing portion  122   b  of the second conductive electrodes  122 . As shown in  FIG. 2A , two fourth enlarging portions  132   a  of the second auxiliary electrodes  132  are located at two sides of one first narrowing portion  121   b  of the first conductive electrodes  121 . 
     Moreover, please referring to table 1, a comparison between the capacitance of the touch panel 100 of the present embodiment and that of a touch panel whose two axis transparent sensing elements are disposed at the same side and crossed via bridge structures. As shown in table 1, the touch panel 100 of the present embodiment has low capacitance under touching or not touching, and the difference between the capacitance under touching and the capacitance under not touching is not conspicuously decreased and the detecting function can be kept. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 The comparison between the touch panels 
               
            
           
           
               
               
               
            
               
                   
                   
                 The touch panel whose two 
               
               
                   
                   
                 axis transparent sensing 
               
               
                   
                   
                 elements are disposed at the 
               
               
                   
                 The touch panel 100 of the 
                 same side and crossed via 
               
               
                   
                 present embodiment 
                 bridge structures 
               
            
           
           
               
               
               
               
               
            
               
                   
                 capacitance 
                 difference 
                 capacitance 
                 Difference 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Under not 
                 1.4962 
                 0.3237 
                 1.9736 
                 0.34 
               
               
                 touching 
                   
                   
                   
                   
               
               
                 Under 
                 1.1725 
                   
                 1.6263 
                   
               
               
                 touching 
               
               
                   
               
            
           
         
       
     
     As shown in  FIGS. 1 to 4 , the shape of the cross-section of the first connecters  141  and the second connecters  142  is exemplified as a circle. In other embodiment, the first connecters  141  and the second connecters  142  can be other shape. Please referring to  FIGS. 5A to 5E ,  FIGS. 5A to 5E  show several embodiments of the first connecters  141  and second connecters  142  of  FIG. 1 . In other embodiment, the shape of the cross-section of the first connecters  141  and the second connecters  142  can be designed as the shape of connecters  240  to  640 . As shown in  FIG. 5A , the cross-section of the connecter  240  is bar shaped. For example, the extending direction of all connecters  240  can be parallel to the first direction C1 or the second direction C2. Or, the extending direction of some of the connecters  240  can extend toward one direction, and the extending direction of others can extend another direction. 
     As shown in  FIG. 5B , the cross-section of the connecter  340  are cross shaped. For example, two extending directions of one connecter  340  can be parallel to the first direction C1 and the second direction C2 respectively. Or, an included angle between two extending directions of one connecter  340  can be 45 degrees. 
     As shown in  FIG. 5C , the cross-section of the connecter  440  is composed of three parallel bars and one connecting bar connected those parallel bars. For example, the extending direction of the parallel bars and the extending direction of the connecting bar can be parallel to the first direction C1 and the second direction C2 respectively. OR, an included angle between the extending direction of the parallel bars and the extending direction of the connecting bar can be 45 degrees. 
     As shown in  FIG. 5D , the cross-section of the connecter  540  is composed of three bars intersected at the same point. For example, three extending directions can be parallel to the first direction C1, parallel to the second direction C2 and inclined to the first direction C1 with 45 degrees respectively. 
     As shown in  FIG. 5E , the cross-section of the connecter  640  is similar to that of a conductive electrode  620 . For example, the connecter  640  and the conductive electrode  620  are rhombus shaped. The four edges of the connecter  640  can be parallel to that of the conductive electrode  620  respectively. 
     As shown in  FIG. 1 , the number of the first connecters  141  corresponding to one first conductive electrode  121  and one first auxiliary electrode  131  is two. In other embodiment, the number of the first connecters  141  corresponding to one first conductive electrode  121  and one first auxiliary electrode  131  can be one, two or more than two. Similarly, the number of the second connecters  142  corresponding to one second conductive electrode  122  and one second auxiliary electrode  132  is two. In other embodiment, the number of the second connecters  142  corresponding to one second conductive electrode  122  and one second auxiliary electrode  132  can be one, two or more than two. 
     The number of the first connecters  141  can be determined according to the ratio of the cross-section of the first connecters  141  to that of the first conductive electrodes  121 . Similarly, the number of the second connecters  142  can be determined according to the ratio of the cross-section of the second connecters  142  to that of the second conductive electrodes  122 . The power loss affected according to the ratio of the cross-section of the connecter  740  to that of the conductive electrodes  720  is analyzed as below. 
     Please referring to  FIGS. 6A to 11B ,  FIGS. 6A to 11B  illustrate an experimental records of the impedance and the power loss according to different ratios of the cross-section of the connecters to that of the conductive electrodes. As shown in  FIGS. 6A ,  7 A,  8 A,  9 A,  10 A and  11 A, the ratios of cross-section of the connecters  740  to that of the conductive electrodes  720  are 22%, 13%, 6%, 1.3%, 0.4% and 0.2% respectively. The numbers of the connecters  740  are gradually decreased.  FIGS. 6B ,  7 B,  8 B,  9 B,  10 B and  11 B illustrate the power loss in  FIGS. 6A ,  7 A,  8 A,  9 A,  10 A and  11 A. In  FIGS. 6B ,  7 B,  8 B,  9 B,  10 B and  11 B, each contour represents one level of the power loss. The innermost contour represents the highest power loss. If one contour is outer than another counter, then the level of the power loss of this contour is lower than that of the another counter. 
     As shown in  FIGS. 6B ,  7 B and  8 B, the distribution of the power loss is symmetrical and uniform, and the range of high power loss is small. As shown in  FIGS. 9B ,  10 B and  11 B, the distribution of the power loss is asymmetry, there are some significant ripples, and the range of high power loss is large. 
     Moreover, regarding the impedance, the impedances measured in  FIGS. 6A ,  7 A,  8 A,  9 A,  10 A and  11 A are 385.48, 386.11, 387.46, 389.41, 393.79 and 398.39 ohm which are gradually increased. 
     If the ratio of the cross-section of the connecters  740  to that of the conductive electrodes  720  is high, then the distribution of the power loss is symmetrical and uniform, the range of high power loss is small and impedance is small. As shown in the experiment, if the ratio of the cross-section area of the connecters  740  to the area of the conductive electrodes  720  is greater than 6%, then the impedance is reduced to be a particular level and the power loss is improved. 
     That is to say, the ratio of the cross-section area of the first connecters  141  to the area of the first conductive electrodes  122  can be greater than 6% for reducing the impedance to be a particular level and improving the power loss. Similarly, the ratio of the cross-section area of the second connecters  142  to the area of the second conductive electrodes  122  can be greater than 6% for reducing the impedance to be a particular level and improving the power loss. 
     In the present embodiment, the area the first conductive electrodes  121  is substantially equal to that of the first auxiliary electrodes  131 . The area of the second conductive electrodes  122  is substantially equal to that of the second auxiliary electrodes  132 . The first conductive electrodes  121  and the first auxiliary electrodes  131  are fully overlapped. 
     In another embodiment, the first side  110   a  of the insulating layer  110  can be a touching side for a finger, the area of the first conductive electrodes  121  can be greater than that of the first auxiliary electrodes  131 , and the area of the second auxiliary electrodes  132  can be greater than that of the second conductive electrodes  122 . 
     In another embodiment, the first side  110   a  of the insulating layer  110  can be a touching side for a finger, the area of the second conductive electrodes  122  can be greater than that of the second auxiliary electrodes  132 , and the area of the first auxiliary electrodes  131  can be greater than that of the first conductive electrodes  121 . 
     Moreover, the shape of the first, second conductive electrodes  121 ,  122  and the shape of the first, second auxiliary electrodes  131 ,  132  can be different. For example, the first, second conductive electrodes  121 ,  122  can be rhombus, the first, second auxiliary electrodes  131 ,  132  can be rectangle, but it is not limited thereto. Further, if a particular shape of one side of the first, second conductive electrodes  121 ,  122  and the first, second auxiliary electrodes  131 ,  132  are irregular, then the shape of the another side of the first, second conductive electrodes  121 ,  122  and the first, second auxiliary electrodes  131 ,  132  can be complementary to that particular shape. For example, the shape of each side can be a rhombus having a plurality of protruding portions and a plurality of concave portions interlaced with each other, the protruding portions on one side correspond to the concave portions on another side, and the concave portions on one side correspond to the protruding portions on another side, such that the visual effects can be well. 
     Moreover, as shown in  FIG. 1 , the first connecters  141  are arranged along the first direction C1, the second connecters  142  are arranged along the second direction C2. That is to say, the first connecters  141  and the first conductive electrodes  121  are arranged along the same direction, and the second connecters  142  and the second conductive electrodes  122  are arranged along the same direction. As a result, the signal transmission capacity of the first conductive electrodes  121  in the first direction C1 can be improved, and the signal transmission capacity of the second conductive electrodes  122  in the second direction C2 can be improved. 
     In the present embodiment, the material of the first conductive electrodes  121 , the material of the second conductive electrodes  122 , the material of the first auxiliary electrodes  131 , the material of the second auxiliary electrodes  132 , the material of the first connecters  141  and the material of the second connecters  142  are the same. The material of the first conductive electrodes  121 , the material of the second conductive electrodes  122 , the material of first auxiliary electrodes  131 , the material of the second auxiliary electrodes  132 , the material of the first connecters  141  and the material of the second connecters  142  can be transparent conductive material, such as indium tin oxide (ITO), or carbon nanotubes. The material of the first connecters  141  and the material of the second connecters  142  can be non-transparent conductive material, such as metal or nano-silver wire. If the materials of those elements are the same, then the efficiency of the manufacturing process can be improved. Moreover, the first, second conductive electrodes  121 ,  122  and the first, second auxiliary electrodes  131 ,  132  are not limited to be continuous thin films, and they can be mesh, such as metal mesh. 
     In another embodiment, the material of the first conductive electrodes  121  and the material of the second conductive electrodes  122  can be different. For example, if the touch panel  100  is rectangle shaped instead of square, the material of the first conductive electrodes  121  and the material of the second conductive electrodes  122  can be different to adjust the impedance distribution of the touch panel  100 , such that the impedance of the long edge of the touch panel  100  and the impedance of the short edge of the touch panel  100  can be similar. 
     In another embodiment, the material of the first conductive electrodes  121  and the material of the first auxiliary electrodes  131  can be different, and the material of the second conductive electrodes  122  and the material of the second auxiliary electrodes  132  can be different. For example, the material of the first conductive electrodes  121  and the second conductive electrodes  122  can be a material having low impedance, and the material of the first auxiliary electrodes  131  and the second auxiliary electrodes  132  can be a material having high impedance. 
     OR, the material of the second conductive electrodes  122  and the first auxiliary electrodes  131  can be a material having low impedance, and the material of the second auxiliary electrodes  132  and the first conductive electrodes  121  can be a material having high impedance. 
     According to the touch panel  100  and the manufacturing method thereof, the first conductive electrodes  121 , the second conductive electrodes  122 , the first auxiliary electrodes  131  and the second auxiliary electrodes  132  are used for reducing the impedance of the touch panel  100  and the capacitance difference can be kept to improve the detecting efficiency. 
     While the disclosure has been described by way of example and in terms of the exemplary embodiment(s), it is to be understood that the disclosure is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.